FAQ
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- Chemical Industry
- CHP and Biogas
- Food Industry
- General
- Industrial Painting and Curing
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- Regulations and Emission Limits
- Retrofit and Replacement Elements
- Service and Maintenance
- Technology and Processes
- Wood Firing and Biomass
- Woodworking and Wood-Based Panels
In many cases, yes. Whether and how a retrofit is possible depends mainly on three factors: the space available in the flue gas path, the temperature at the intended installation point and the dust load. If the temperature downstream of the dust filter is too low, a heat exchanger or auxiliary heating may be required. A storage and dosing system for the reducing agent, usually urea solution, is also needed, together with a control system that adjusts the dosing rate to the load. In heating plants with strongly fluctuating heat demand, this load behaviour is a central aspect of the design. Existing components such as filters, induced draught fan and stack are included in the planning and reused wherever possible. For an initial assessment, a layout drawing or photos of the flue gas path, details of the thermal output and fuel, and the latest emission measurement report are helpful. With these documents, we can check which retrofit option is technically appropriate for your plant.
Yes, in many cases professional cleaning and regeneration is possible and makes economic sense. Deposits of ash, dust or light oil residues block the active sites of the catalyst. Special chemical washing processes can remove these deposits and largely restore the original catalytic activity. This extends the service life of the catalyst considerably and is usually much less expensive than a replacement.
Yes, substances such as silicones, heavy metals, sulphur or halogen compounds can affect catalysts. Pure Air therefore carries out detailed gas analyses in advance and uses targeted pre-filters, guard beds or catalyst types with resistant doping.
That depends on the moisture and pollutant profiles. Exhaust air streams are often thermally preconditioned or captured separately so that the catalyst operates within its optimum range.
Yes, many systems can be retrofitted or optimized with catalytic systems. A precise analysis of the exhaust air flows is crucial in order to integrate the right solution.
Yes, retrofits are a typical application, especially to adapt existing press and dryer lines to tightened emission limits.
In principle, yes, but this type of exhaust air places special demands on the system. Chlorinated or fluorinated hydrocarbons can be oxidised on suitable catalysts. In addition to carbon dioxide and water, this produces acid gases such as hydrogen chloride or hydrogen fluoride. This has three consequences for planning. First, the catalyst type and support material must be resistant to halogens, as standard coatings can be deactivated by them. Second, materials for the housing and pipework must be selected to withstand the acidic reaction products, particularly where the temperature may fall below the dew point. Third, a scrubber is usually required downstream of the catalyst to remove the acid gases. It must also be checked whether undesirable by-products can form under the operating conditions. A reliable design therefore requires detailed knowledge of the exhaust air composition. Provide us with substance lists, concentration ranges and process descriptions so that we can assess whether a catalytic process is suitable.
Yes, this is often possible and is considered during the design phase. In catalytic oxidation, organic substances in the exhaust air are converted into carbon dioxide and water vapour. This releases reaction heat, and the cleaned gas leaves the catalyst at a higher temperature. This heat can be used via a heat exchanger, for example to preheat the exhaust air to be treated, to produce hot water or thermal oil, or to support drying and roasting processes. How much heat can usefully be recovered depends on the pollutant concentration, the flow rate, the operating hours and whether there is a suitable heat consumer on site. In plants with frequent downtimes or frequently changing recipes, the balance looks different from that of continuous operation. If you provide us with your exhaust air data and your heat demand, we will check whether heat recovery makes technical and economic sense for your process.
Yes, that is one of our core competencies. We analyze your existing system and integrate state-of-the-art catalyst technology into existing housings to reduce investment costs.
Yes, the performance of a catalytic converter can be impaired by ageing or impurities (e.g. sulphur, siloxanes). Regular monitoring and maintenance are therefore crucial for a permanently high separation efficiency.
As a rule, yes. Exhaust air from frying, roasting and smoking equipment contains not only gaseous odour compounds but also fat and oil droplets and soot particles. If these reach the catalyst unfiltered, they clog the surface, can carbonise and noticeably reduce the cleaning performance. For this reason, pre-separation is usually planned upstream of the catalyst, for example with grease filters, aerosol separators or thermal pretreatment. The right solution depends on the fat load, the exhaust air temperature and the cleaning effort you can manage in day-to-day operation. Maintenance access to the filters should also be considered from the outset so that filter changes and cleaning can be carried out without major effort. If a catalyst is already coated with fat or oil residues, chemical cleaning can often restore its activity. Describe your process, production hours and existing exhaust air ducting to us, and we will check which pre-separation suits your plant.
Yes. Contaminated catalysts (e.g. due to ash or oil) can often be regenerated using our special washing processes, which significantly extends their service life.
Absolutely. We manufacture or source high-performance components that can be seamlessly integrated into enclosures from other manufacturers, often with better performance than the original.
Yes, our SCR systems and oxidation catalytic converters are specially designed to safely and permanently comply with the strict limits of the 44th BImSchV for nitrogen oxides (NOx), formaldehyde and carbon monoxide.
Replacing catalyst elements does not require replacing the entire housing. After the existing system has been measured and analysed, precisely fitting replacement catalysts, for example in honeycomb or plate form, are produced. These elements are matched to the existing support frames of the third-party housing and exchanged on site. In many cases, this even allows the cleaning performance to be improved within the same installation space.
A declining catalyst usually shows itself gradually. The clearest sign is rising emission values in the periodic measurement or in your own check measurements, for example for CO, formaldehyde or NOx, although the engine or process is running unchanged. A second indicator is the differential pressure across the catalyst: if it rises, this points to deposits narrowing the channels. With oxidation catalysts, the temperature difference between inlet and outlet is also informative, because an active catalyst heats the exhaust gas through the reaction heat. In SCR systems, an increasing reducing agent demand or ammonia slip can indicate declining activity. Visible deposits, discolouration or mechanical damage found during inspection complete the picture. Not every loss of performance means replacement: fouling can often be remedied by cleaning or regeneration, whereas poisoning usually cannot. Send us current measured values, differential pressure trends and photos of the elements, and we will assess the condition of your catalyst.
Roasting, baking, frying and smoking processes in the food industry release strongly smelling organic compounds and fat aerosols. Catalytic exhaust air treatment breaks down and oxidises these odour-intensive hydrocarbons at low temperatures. The result is process exhaust air that is largely odour-neutral and compliant with regulations, which helps to avoid conflicts with neighbours and authorities.
Catalysts specifically reduce critical pollutants such as VOCs, CO and formaldehyde. This ensures that emission limits are reliably complied with – even under varying operating conditions.
With careful engineering and preheating sections, catalytic systems can respond flexibly to peak loads and load changes without loss of efficiency or thermal overload.
In catalytic oxidation, volatile organic compounds (VOCs) and solvent vapours are converted into harmless substances such as carbon dioxide and water vapour at comparatively low temperatures, usually between 250 and 400 degrees Celsius. Thermal oxidation, by contrast, requires temperatures well above 700 degrees Celsius. The catalytic process therefore saves a significant amount of energy and operating cost, as little or no additional fossil fuel is needed.
SCR catalysts (Selective Catalytic Reduction) are the established technology for reducing nitrogen oxides (NOx) in continuous industrial operation. A reducing agent such as urea solution or AdBlue is injected into the exhaust gas stream, and the nitrogen oxides are selectively converted into elemental nitrogen and water vapour on the catalyst. The reduction that can be achieved in a specific plant depends on the exhaust gas temperature, the dosing and the design of the catalyst, which is why it is determined during engineering.
As an agile company, you will usually receive initial feedback within 24 hours and a technical concept promptly.
Flue gas from wood and biomass combustion contains fly ash that can block channels and cover active surfaces. Wood ash also contains alkali metals such as potassium, which gradually deactivate SCR catalysts. The most important protection is effective dust removal upstream of the catalyst. In addition, catalysts with a larger cell pitch or plate-type elements are used, as they are less prone to clogging, and cleaning devices such as soot blowers or compressed air pulses are installed. The position in the flue gas path also matters: placing the catalyst downstream of the dust filter relieves it but may require the flue gas to be reheated. During operation, a rising differential pressure is an early sign that deposits are forming. In many cases, fouled elements can be cleaned or regenerated before replacement becomes necessary. Send us details of the fuel, the filter technology and the flue gas temperatures, and we will assess which protective measures make sense for your plant.
In printing presses, solvents are released at several points: at inking units, dryers, laminating units and into the hall air. Targeted capture at the sources is important for economical catalytic treatment, because the higher the solvent concentration in the exhaust air, the less additional energy the catalyst requires. A common approach is recirculation in the dryers, where part of the dryer air is returned and the concentration increases as a result. For large flow rates with low concentrations, upstream concentration, for example with an adsorption wheel, can make sense. For safety reasons, the concentration must always remain well below the lower explosive limit, which is monitored by measuring equipment. Changing print jobs and downtime at individual presses also influence the design. Send us the number and type of presses, the solvents used and any existing exhaust air measurements, and we will check how your exhaust air can be captured and treated effectively.
Formaldehyde-based binders are used in the production of particleboard, MDF and OSB. In the press and while the boards cool, formaldehyde and other organic compounds enter the exhaust air, often together with wood dust, resin aerosols and a high moisture content. For catalytic oxidation of this exhaust air, pretreatment comes first: dust and sticky aerosols must be removed to the extent that they cannot clog the catalyst. The exhaust air is then brought to the required reaction temperature, often supported by heat exchangers that recover energy from the cleaned gas. Because press exhaust air has large flow rates at comparatively low concentrations, the energy balance is an essential part of the design. The temperature profile must also be chosen so that no condensate forms in the system. If you send us the flow rate, exhaust air temperature, measured values for formaldehyde and total carbon and details of the dust removal, we will check a suitable concept for your press.
It is not possible to give a general figure, because the duration depends on several factors. Preparation has the greatest influence: if the dimensions, design and support frames of the existing housing are known, the replacement elements can be manufactured or sourced in advance, and the actual exchange on site is limited to removal, installation and testing. For housings from other manufacturers without complete documentation, the housing first has to be measured. On site, the accessibility of the housing, the cooling time of the plant, the size and weight of the elements, the lifting equipment required and the condition of seals and frames all play a role. In SCR systems, work on the dosing equipment may also be needed. To keep downtime short, it is advisable to combine the replacement with maintenance work already planned on the engine or process plant. Send us the type plate, a housing drawing or photos and details of accessibility, and we will plan the replacement together with you.
The maintenance interval depends heavily on the mode of operation and the composition of the exhaust gas. With clean exhaust gas, for example from a natural gas CHP unit, an annual inspection is often sufficient. For demanding processes with dust or potential catalyst poisons, such as biogas or industrial process exhaust air, a check every six months is advisable. Regular measurement of the differential pressure and the conversion rate helps to detect fouling early, before emission limits are exceeded.
That depends on your permit, the regulation that applies to your plant and the type of change. Replacing catalyst elements with equivalent ones as part of maintenance is assessed differently from a modification in which the design, construction or cleaning process changes. In the latter case, notification of or consultation with the authority may be required, often combined with a measurement that demonstrates compliance with the emission requirements. Even where no measurement is mandatory, a check measurement can be useful to document the effect of the new elements and provide a baseline for later comparisons. It is best to clarify the requirements early with your authority or your measuring body so that the replacement and the measurement date can be coordinated. Technical documentation on the installed catalyst elements is helpful for this coordination. Let us know which evidence your authority requires, and we will align the documentation for the replacement accordingly.
Catalytic processes operate at much lower temperatures (often 250 to 450 °C compared with more than 800 °C for an RTO). This saves a considerable amount of fuel, reduces the carbon footprint and requires less installation space.
Catalytic systems deliver consistent cleaning performance regardless of weather, microbial load or biological activity, and they require no water or sludge treatment.
Catalytic systems enable the oxidation of pollutants at significantly lower temperatures. This reduces energy consumption, lowers operating costs, and allows for a more compact system design.
Regenerating SCR catalysts restores their full denitrification performance (NOx reduction) when the catalyst is blocked by deposits such as ammonium sulphate or dust. Special thermal or chemical processes remove these blockages. Regeneration conserves resources, avoids the purchase of expensive new modules and ensures that the plant once again operates with low ammonia or AdBlue consumption and at its intended efficiency.
The cost of a retrofit depends largely on the size of the plant, the exhaust gas flow rate and the emission limits to be met. In general, modernising an existing system is considerably more cost-effective than a complete new installation. Because existing housings, pipework and infrastructure continue to be used, both the hardware investment and the production downtime during the conversion are reduced.
The 44th BImSchV sets stricter emission limits for existing and new medium combustion plants, gas turbines and combustion engines (CHP). For existing plants, staggered transition periods apply depending on rated output and fuel type before the new limits for nitrogen oxides (NOx), carbon monoxide (CO) and formaldehyde must be met. Operators often have to retrofit their plants with SCR systems or oxidation catalysts in order to reliably achieve the required values and avoid losing their operating permit.
As catalytic oxidation takes place at lower temperatures, less energy is required for exhaust air purification. This can significantly reduce operating costs and improve the overall energy efficiency of the system.
In addition to CO₂ and water vapor, nitrogen oxides (NOₓ), carbon monoxide (CO) and unburned hydrocarbons – in particular VOCs and formaldehyde – are also produced during operation. The level of emissions depends heavily on the gas quality and combustion efficiency.
The 31st BImSchV regulates emissions of volatile organic compounds from installations that use solvents, for example in printing, painting or packaging production. Operators covered by the regulation must document their solvent flows in a solvent management plan, also known as a solvent balance. It compares the solvents fed into the installation with where they end up: in the product, in waste, in the captured and treated exhaust air or as fugitive emissions via room air and windows. The authority uses this balance as evidence that the requirements of the regulation are being met. Catalytic exhaust air treatment has a direct effect on this balance, as it reduces the share of captured solvents that actually reach the environment. The better the capture at the machines, the lower the fugitive share. If you provide your current solvent management plan and details of your exhaust air ducting, we can assess the contribution that exhaust air treatment can make.
Ammonia slip refers to ammonia that passes through the SCR catalyst unused and is released into the environment with the exhaust gas. It occurs when more reducing agent is dosed than can react with nitrogen oxides on the catalyst. Causes include overdosing, uneven distribution of the reducing agent across the exhaust gas cross-section, exhaust gas temperatures that are too low, rapid load changes or a catalyst whose activity has declined. Ammonia slip is undesirable for several reasons: ammonia is itself an air pollutant, it can form deposits in combination with sulphur compounds, and it means unnecessary consumption of urea solution. It can be avoided with load-dependent dosing control, a sufficient mixing section upstream of the catalyst, an appropriate catalyst design and regular checks of the dosing equipment. In addition, a downstream oxidation catalyst can convert remaining ammonia. If your measurement reports show ammonia or your urea consumption is rising, send us the data so that we can assess the dosing and catalyst condition together with you.
Catalyst poisoning occurs when certain chemical elements bind irreversibly to the active surface of the catalyst and permanently impair its function. Typical catalyst poisons in industry and in biogas plants are sulphur, silicon (siloxanes), phosphorus, lead and other heavy metals. While ordinary fouling can be washed off, genuine catalyst poisoning usually means that the affected catalyst elements have to be replaced.
Conventional oxidation catalysts use precious metals such as platinum or palladium as the active layer. Perovskite catalysts, on the other hand, are based on a specific crystalline structure of mixed metal oxides. They offer good thermal stability and are effective at oxidising carbon monoxide and hydrocarbons. They are often less sensitive to certain contaminants and, particularly when precious metal prices rise, are an economically attractive alternative.
An oxidation catalytic converter reduces carbon monoxide (CO) and formaldehyde through oxidation. An SCR catalytic converter (Selective Catalytic Reduction) minimizes nitrogen oxides (NOx) by adding a reducing agent (urea/AdBlue). We often combine both technologies.
The current TA Luft (Technical Instructions on Air Quality Control) has significantly tightened the requirements for formaldehyde emissions. The value that applies to a specific industrial plant or biogas CHP unit depends on the plant type and the individual permit, and in some permitting procedures the authority requires even lower values under the minimisation requirement. Oxidation catalysts are used to comply with these values reliably, as they convert formaldehyde in the exhaust gas into carbon dioxide and water vapour.
After long shutdowns, for example due to seasonal operation, overhauls or production breaks, moisture can condense in the catalyst and the exhaust gas path. Together with deposits from operation, this can form acids or salts that affect the catalyst. When restarting, the system should therefore be heated up as evenly as possible so that condensate can evaporate and no thermal stresses develop in the elements. In SCR systems, reducing agent dosing should only be enabled once the minimum temperature at the catalyst has been reached, as deposits can otherwise form. Before start-up, it is worth checking seals, measuring points and dosing lines, especially if the plant was shut down over the winter. Monitor the differential pressure and temperatures during the first hours of operation to detect anomalies early. If you regularly have long shutdowns, start-up and preservation steps can be set out in an operating instruction. Contact us if you would like support in assessing your plant.
First, evaluate the measurement report carefully: which component exceeded the limit, under which load condition and by how much? Also inform the competent authority if your permit or the applicable regulation requires this, and clarify the next steps and the deadline for a repeat measurement with them. On the technical side, it is worth looking at the causes systematically. Common reasons include an aged or fouled catalyst, incorrect engine or burner settings, faulty reducing agent dosing in SCR systems or a catalyst that is undersized for the operating conditions. Differential pressure, temperatures upstream and downstream of the catalyst and operating hours provide important clues. Depending on the findings, cleaning or regeneration may be sufficient; in other cases, the elements need to be replaced or the design adjusted. Send us the measurement report and the key plant data via our page for urgent cases. You will usually receive initial feedback within 24 hours.
We scale flexibly. From compact CHP units (from approx. 100 kW) to large industrial plants or waste incineration in the megawatt range, we develop suitable concepts.
Catalytic converters are particularly efficient at medium VOC concentrations and constant exhaust air flows. They offer advantages when the focus is on energy efficiency and operating costs.
Catalytic converters are usually installed in the exhaust tract downstream of the engine. Depending on the system, oxidation catalytic converters or combined solutions are used, which are specially adapted to the composition of biogas.
Two types of catalyst are mainly used in biogas CHP units: oxidation catalysts to reduce formaldehyde and carbon monoxide (CO), and SCR catalysts where a substantial reduction of nitrogen oxides (NOx) is required. As biogas often contains traces of hydrogen sulphide and siloxanes, the catalysts must either be designed to be particularly robust or be protected upstream by suitable gas cleaning systems such as activated carbon filters.
For a reliable design, we need information on the exhaust gas or exhaust air, the plant and the requirements. Important factors are the flow rate, the temperature at the intended installation point, the gas composition with the relevant pollutant concentrations and details of moisture, dust and possible catalyst poisons such as sulphur, siloxanes or silicones. We also need information on the plant itself: engine or combustion type, output, fuel, process description and mode of operation, i.e. continuous operation, part load or batch operation. On the requirements side, we need the permit or the emission values to be met and, if available, recent measurement reports. For retrofits or replacement elements, drawings, photos and dimensions of the existing housing are helpful, as are details of the available space and the permissible pressure drop. Not all data has to be complete to get started, as missing values can often be determined together. Send us the documents you have, and you will usually receive initial feedback within 24 hours.
In addition to catalytic systems, thermal post-combustion (RTO), adsorption (e.g. activated carbon) or combinations of these processes are also used. The choice depends on the volume flow, VOC concentration and process conditions.
Catalytic exhaust air treatment is required or economically sensible in all industries that release volatile organic compounds (VOCs). These include industrial painting and coating lines, the chemical industry, printing and packaging companies (flexographic and gravure printing), woodworking (gluing and drying) and the plastics processing industry. Treating the exhaust air protects the environment and prevents odour nuisance in the neighbourhood.
Limits for carbon monoxide (CO) vary depending on the type of plant, the fuel used and the relevant legal basis, for example TA Luft or the 44th BImSchV. For many industrial combustion engines and combustion plants, CO limits have been tightened considerably by more recent regulations. The value that applies to your plant is set out in the regulation and in your permit. Oxidation catalysts are an effective way of keeping CO emissions reliably below these limits.
Burning wood, wood chips, pellets or residues produces dust and, above all, nitrogen oxides (NOx), carbon monoxide (CO) and unburnt organic compounds. Nitrogen oxides can be reduced with an SCR catalyst and a reducing agent, while CO and organic components are treated with an oxidation catalyst. Dust itself is not removed catalytically but separated by cyclones, fabric filters or electrostatic precipitators. Which combination makes sense depends on the fuel, the combustion technology, the load profile and the requirements in your permit. The temperature window and dust removal are often the deciding factors in the design, because the catalyst must be located at a point in the flue gas path where the temperature is suitable and the dust load is manageable. If you send us the fuel type, the thermal output and a recent emission measurement report, we will assess which catalyst technology is suitable for your plant.
The highest VOC emissions typically occur during paint application, flash-off and thermal curing. Continuous exhaust air flows from drying ovens are particularly critical.
Biogas is not a fuel with a constant composition. Fluctuations in methane content or impurities can lead to incomplete combustion – and thus to increased VOC emissions. These must be treated in a targeted manner in order to comply with limit values.
Paints often contain solvents that are released as VOCs when they evaporate. These are harmful to the environment and health and are subject to strict legal requirements, which makes effective exhaust air purification absolutely essential.
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General 9
Yes, that is one of our core competencies. We analyze your existing system and integrate state-of-the-art catalyst technology into existing housings to reduce investment costs.
Yes. Contaminated catalysts (e.g. due to ash or oil) can often be regenerated using our special washing processes, which significantly extends their service life.
Absolutely. We manufacture or source high-performance components that can be seamlessly integrated into enclosures from other manufacturers, often with better performance than the original.
Yes, our SCR systems and oxidation catalytic converters are specially designed to safely and permanently comply with the strict limits of the 44th BImSchV for nitrogen oxides (NOx), formaldehyde and carbon monoxide.
As an agile company, you will usually receive initial feedback within 24 hours and a technical concept promptly.
An oxidation catalytic converter reduces carbon monoxide (CO) and formaldehyde through oxidation. An SCR catalytic converter (Selective Catalytic Reduction) minimizes nitrogen oxides (NOx) by adding a reducing agent (urea/AdBlue). We often combine both technologies.
We scale flexibly. From compact CHP units (from approx. 100 kW) to large industrial plants or waste incineration in the megawatt range, we develop suitable concepts.
For a reliable design, we need information on the exhaust gas or exhaust air, the plant and the requirements. Important factors are the flow rate, the temperature at the intended installation point, the gas composition with the relevant pollutant concentrations and details of moisture, dust and possible catalyst poisons such as sulphur, siloxanes or silicones. We also need information on the plant itself: engine or combustion type, output, fuel, process description and mode of operation, i.e. continuous operation, part load or batch operation. On the requirements side, we need the permit or the emission values to be met and, if available, recent measurement reports. For retrofits or replacement elements, drawings, photos and dimensions of the existing housing are helpful, as are details of the available space and the permissible pressure drop. Not all data has to be complete to get started, as missing values can often be determined together. Send us the documents you have, and you will usually receive initial feedback within 24 hours.
Catalytic exhaust air treatment is required or economically sensible in all industries that release volatile organic compounds (VOCs). These include industrial painting and coating lines, the chemical industry, printing and packaging companies (flexographic and gravure printing), woodworking (gluing and drying) and the plastics processing industry. Treating the exhaust air protects the environment and prevents odour nuisance in the neighbourhood.
Technology and Processes 20
In principle, yes, but this type of exhaust air places special demands on the system. Chlorinated or fluorinated hydrocarbons can be oxidised on suitable catalysts. In addition to carbon dioxide and water, this produces acid gases such as hydrogen chloride or hydrogen fluoride. This has three consequences for planning. First, the catalyst type and support material must be resistant to halogens, as standard coatings can be deactivated by them. Second, materials for the housing and pipework must be selected to withstand the acidic reaction products, particularly where the temperature may fall below the dew point. Third, a scrubber is usually required downstream of the catalyst to remove the acid gases. It must also be checked whether undesirable by-products can form under the operating conditions. A reliable design therefore requires detailed knowledge of the exhaust air composition. Provide us with substance lists, concentration ranges and process descriptions so that we can assess whether a catalytic process is suitable.
Yes, this is often possible and is considered during the design phase. In catalytic oxidation, organic substances in the exhaust air are converted into carbon dioxide and water vapour. This releases reaction heat, and the cleaned gas leaves the catalyst at a higher temperature. This heat can be used via a heat exchanger, for example to preheat the exhaust air to be treated, to produce hot water or thermal oil, or to support drying and roasting processes. How much heat can usefully be recovered depends on the pollutant concentration, the flow rate, the operating hours and whether there is a suitable heat consumer on site. In plants with frequent downtimes or frequently changing recipes, the balance looks different from that of continuous operation. If you provide us with your exhaust air data and your heat demand, we will check whether heat recovery makes technical and economic sense for your process.
As a rule, yes. Exhaust air from frying, roasting and smoking equipment contains not only gaseous odour compounds but also fat and oil droplets and soot particles. If these reach the catalyst unfiltered, they clog the surface, can carbonise and noticeably reduce the cleaning performance. For this reason, pre-separation is usually planned upstream of the catalyst, for example with grease filters, aerosol separators or thermal pretreatment. The right solution depends on the fat load, the exhaust air temperature and the cleaning effort you can manage in day-to-day operation. Maintenance access to the filters should also be considered from the outset so that filter changes and cleaning can be carried out without major effort. If a catalyst is already coated with fat or oil residues, chemical cleaning can often restore its activity. Describe your process, production hours and existing exhaust air ducting to us, and we will check which pre-separation suits your plant.
In catalytic oxidation, volatile organic compounds (VOCs) and solvent vapours are converted into harmless substances such as carbon dioxide and water vapour at comparatively low temperatures, usually between 250 and 400 degrees Celsius. Thermal oxidation, by contrast, requires temperatures well above 700 degrees Celsius. The catalytic process therefore saves a significant amount of energy and operating cost, as little or no additional fossil fuel is needed.
SCR catalysts (Selective Catalytic Reduction) are the established technology for reducing nitrogen oxides (NOx) in continuous industrial operation. A reducing agent such as urea solution or AdBlue is injected into the exhaust gas stream, and the nitrogen oxides are selectively converted into elemental nitrogen and water vapour on the catalyst. The reduction that can be achieved in a specific plant depends on the exhaust gas temperature, the dosing and the design of the catalyst, which is why it is determined during engineering.
Flue gas from wood and biomass combustion contains fly ash that can block channels and cover active surfaces. Wood ash also contains alkali metals such as potassium, which gradually deactivate SCR catalysts. The most important protection is effective dust removal upstream of the catalyst. In addition, catalysts with a larger cell pitch or plate-type elements are used, as they are less prone to clogging, and cleaning devices such as soot blowers or compressed air pulses are installed. The position in the flue gas path also matters: placing the catalyst downstream of the dust filter relieves it but may require the flue gas to be reheated. During operation, a rising differential pressure is an early sign that deposits are forming. In many cases, fouled elements can be cleaned or regenerated before replacement becomes necessary. Send us details of the fuel, the filter technology and the flue gas temperatures, and we will assess which protective measures make sense for your plant.
In printing presses, solvents are released at several points: at inking units, dryers, laminating units and into the hall air. Targeted capture at the sources is important for economical catalytic treatment, because the higher the solvent concentration in the exhaust air, the less additional energy the catalyst requires. A common approach is recirculation in the dryers, where part of the dryer air is returned and the concentration increases as a result. For large flow rates with low concentrations, upstream concentration, for example with an adsorption wheel, can make sense. For safety reasons, the concentration must always remain well below the lower explosive limit, which is monitored by measuring equipment. Changing print jobs and downtime at individual presses also influence the design. Send us the number and type of presses, the solvents used and any existing exhaust air measurements, and we will check how your exhaust air can be captured and treated effectively.
Formaldehyde-based binders are used in the production of particleboard, MDF and OSB. In the press and while the boards cool, formaldehyde and other organic compounds enter the exhaust air, often together with wood dust, resin aerosols and a high moisture content. For catalytic oxidation of this exhaust air, pretreatment comes first: dust and sticky aerosols must be removed to the extent that they cannot clog the catalyst. The exhaust air is then brought to the required reaction temperature, often supported by heat exchangers that recover energy from the cleaned gas. Because press exhaust air has large flow rates at comparatively low concentrations, the energy balance is an essential part of the design. The temperature profile must also be chosen so that no condensate forms in the system. If you send us the flow rate, exhaust air temperature, measured values for formaldehyde and total carbon and details of the dust removal, we will check a suitable concept for your press.
Catalytic processes operate at much lower temperatures (often 250 to 450 °C compared with more than 800 °C for an RTO). This saves a considerable amount of fuel, reduces the carbon footprint and requires less installation space.
Catalytic systems deliver consistent cleaning performance regardless of weather, microbial load or biological activity, and they require no water or sludge treatment.
Catalytic systems enable the oxidation of pollutants at significantly lower temperatures. This reduces energy consumption, lowers operating costs, and allows for a more compact system design.
Ammonia slip refers to ammonia that passes through the SCR catalyst unused and is released into the environment with the exhaust gas. It occurs when more reducing agent is dosed than can react with nitrogen oxides on the catalyst. Causes include overdosing, uneven distribution of the reducing agent across the exhaust gas cross-section, exhaust gas temperatures that are too low, rapid load changes or a catalyst whose activity has declined. Ammonia slip is undesirable for several reasons: ammonia is itself an air pollutant, it can form deposits in combination with sulphur compounds, and it means unnecessary consumption of urea solution. It can be avoided with load-dependent dosing control, a sufficient mixing section upstream of the catalyst, an appropriate catalyst design and regular checks of the dosing equipment. In addition, a downstream oxidation catalyst can convert remaining ammonia. If your measurement reports show ammonia or your urea consumption is rising, send us the data so that we can assess the dosing and catalyst condition together with you.
Catalyst poisoning occurs when certain chemical elements bind irreversibly to the active surface of the catalyst and permanently impair its function. Typical catalyst poisons in industry and in biogas plants are sulphur, silicon (siloxanes), phosphorus, lead and other heavy metals. While ordinary fouling can be washed off, genuine catalyst poisoning usually means that the affected catalyst elements have to be replaced.
Conventional oxidation catalysts use precious metals such as platinum or palladium as the active layer. Perovskite catalysts, on the other hand, are based on a specific crystalline structure of mixed metal oxides. They offer good thermal stability and are effective at oxidising carbon monoxide and hydrocarbons. They are often less sensitive to certain contaminants and, particularly when precious metal prices rise, are an economically attractive alternative.
An oxidation catalytic converter reduces carbon monoxide (CO) and formaldehyde through oxidation. An SCR catalytic converter (Selective Catalytic Reduction) minimizes nitrogen oxides (NOx) by adding a reducing agent (urea/AdBlue). We often combine both technologies.
After long shutdowns, for example due to seasonal operation, overhauls or production breaks, moisture can condense in the catalyst and the exhaust gas path. Together with deposits from operation, this can form acids or salts that affect the catalyst. When restarting, the system should therefore be heated up as evenly as possible so that condensate can evaporate and no thermal stresses develop in the elements. In SCR systems, reducing agent dosing should only be enabled once the minimum temperature at the catalyst has been reached, as deposits can otherwise form. Before start-up, it is worth checking seals, measuring points and dosing lines, especially if the plant was shut down over the winter. Monitor the differential pressure and temperatures during the first hours of operation to detect anomalies early. If you regularly have long shutdowns, start-up and preservation steps can be set out in an operating instruction. Contact us if you would like support in assessing your plant.
Catalytic converters are usually installed in the exhaust tract downstream of the engine. Depending on the system, oxidation catalytic converters or combined solutions are used, which are specially adapted to the composition of biogas.
For a reliable design, we need information on the exhaust gas or exhaust air, the plant and the requirements. Important factors are the flow rate, the temperature at the intended installation point, the gas composition with the relevant pollutant concentrations and details of moisture, dust and possible catalyst poisons such as sulphur, siloxanes or silicones. We also need information on the plant itself: engine or combustion type, output, fuel, process description and mode of operation, i.e. continuous operation, part load or batch operation. On the requirements side, we need the permit or the emission values to be met and, if available, recent measurement reports. For retrofits or replacement elements, drawings, photos and dimensions of the existing housing are helpful, as are details of the available space and the permissible pressure drop. Not all data has to be complete to get started, as missing values can often be determined together. Send us the documents you have, and you will usually receive initial feedback within 24 hours.
In addition to catalytic systems, thermal post-combustion (RTO), adsorption (e.g. activated carbon) or combinations of these processes are also used. The choice depends on the volume flow, VOC concentration and process conditions.
Burning wood, wood chips, pellets or residues produces dust and, above all, nitrogen oxides (NOx), carbon monoxide (CO) and unburnt organic compounds. Nitrogen oxides can be reduced with an SCR catalyst and a reducing agent, while CO and organic components are treated with an oxidation catalyst. Dust itself is not removed catalytically but separated by cyclones, fabric filters or electrostatic precipitators. Which combination makes sense depends on the fuel, the combustion technology, the load profile and the requirements in your permit. The temperature window and dust removal are often the deciding factors in the design, because the catalyst must be located at a point in the flue gas path where the temperature is suitable and the dust load is manageable. If you send us the fuel type, the thermal output and a recent emission measurement report, we will assess which catalyst technology is suitable for your plant.
Regulations and Emission Limits 8
Yes, our SCR systems and oxidation catalytic converters are specially designed to safely and permanently comply with the strict limits of the 44th BImSchV for nitrogen oxides (NOx), formaldehyde and carbon monoxide.
Catalysts specifically reduce critical pollutants such as VOCs, CO and formaldehyde. This ensures that emission limits are reliably complied with – even under varying operating conditions.
That depends on your permit, the regulation that applies to your plant and the type of change. Replacing catalyst elements with equivalent ones as part of maintenance is assessed differently from a modification in which the design, construction or cleaning process changes. In the latter case, notification of or consultation with the authority may be required, often combined with a measurement that demonstrates compliance with the emission requirements. Even where no measurement is mandatory, a check measurement can be useful to document the effect of the new elements and provide a baseline for later comparisons. It is best to clarify the requirements early with your authority or your measuring body so that the replacement and the measurement date can be coordinated. Technical documentation on the installed catalyst elements is helpful for this coordination. Let us know which evidence your authority requires, and we will align the documentation for the replacement accordingly.
The 44th BImSchV sets stricter emission limits for existing and new medium combustion plants, gas turbines and combustion engines (CHP). For existing plants, staggered transition periods apply depending on rated output and fuel type before the new limits for nitrogen oxides (NOx), carbon monoxide (CO) and formaldehyde must be met. Operators often have to retrofit their plants with SCR systems or oxidation catalysts in order to reliably achieve the required values and avoid losing their operating permit.
The 31st BImSchV regulates emissions of volatile organic compounds from installations that use solvents, for example in printing, painting or packaging production. Operators covered by the regulation must document their solvent flows in a solvent management plan, also known as a solvent balance. It compares the solvents fed into the installation with where they end up: in the product, in waste, in the captured and treated exhaust air or as fugitive emissions via room air and windows. The authority uses this balance as evidence that the requirements of the regulation are being met. Catalytic exhaust air treatment has a direct effect on this balance, as it reduces the share of captured solvents that actually reach the environment. The better the capture at the machines, the lower the fugitive share. If you provide your current solvent management plan and details of your exhaust air ducting, we can assess the contribution that exhaust air treatment can make.
The current TA Luft (Technical Instructions on Air Quality Control) has significantly tightened the requirements for formaldehyde emissions. The value that applies to a specific industrial plant or biogas CHP unit depends on the plant type and the individual permit, and in some permitting procedures the authority requires even lower values under the minimisation requirement. Oxidation catalysts are used to comply with these values reliably, as they convert formaldehyde in the exhaust gas into carbon dioxide and water vapour.
First, evaluate the measurement report carefully: which component exceeded the limit, under which load condition and by how much? Also inform the competent authority if your permit or the applicable regulation requires this, and clarify the next steps and the deadline for a repeat measurement with them. On the technical side, it is worth looking at the causes systematically. Common reasons include an aged or fouled catalyst, incorrect engine or burner settings, faulty reducing agent dosing in SCR systems or a catalyst that is undersized for the operating conditions. Differential pressure, temperatures upstream and downstream of the catalyst and operating hours provide important clues. Depending on the findings, cleaning or regeneration may be sufficient; in other cases, the elements need to be replaced or the design adjusted. Send us the measurement report and the key plant data via our page for urgent cases. You will usually receive initial feedback within 24 hours.
Limits for carbon monoxide (CO) vary depending on the type of plant, the fuel used and the relevant legal basis, for example TA Luft or the 44th BImSchV. For many industrial combustion engines and combustion plants, CO limits have been tightened considerably by more recent regulations. The value that applies to your plant is set out in the regulation and in your permit. Oxidation catalysts are an effective way of keeping CO emissions reliably below these limits.
Service and Maintenance 12
Yes, in many cases professional cleaning and regeneration is possible and makes economic sense. Deposits of ash, dust or light oil residues block the active sites of the catalyst. Special chemical washing processes can remove these deposits and largely restore the original catalytic activity. This extends the service life of the catalyst considerably and is usually much less expensive than a replacement.
Yes, the performance of a catalytic converter can be impaired by ageing or impurities (e.g. sulphur, siloxanes). Regular monitoring and maintenance are therefore crucial for a permanently high separation efficiency.
Yes. Contaminated catalysts (e.g. due to ash or oil) can often be regenerated using our special washing processes, which significantly extends their service life.
Replacing catalyst elements does not require replacing the entire housing. After the existing system has been measured and analysed, precisely fitting replacement catalysts, for example in honeycomb or plate form, are produced. These elements are matched to the existing support frames of the third-party housing and exchanged on site. In many cases, this even allows the cleaning performance to be improved within the same installation space.
A declining catalyst usually shows itself gradually. The clearest sign is rising emission values in the periodic measurement or in your own check measurements, for example for CO, formaldehyde or NOx, although the engine or process is running unchanged. A second indicator is the differential pressure across the catalyst: if it rises, this points to deposits narrowing the channels. With oxidation catalysts, the temperature difference between inlet and outlet is also informative, because an active catalyst heats the exhaust gas through the reaction heat. In SCR systems, an increasing reducing agent demand or ammonia slip can indicate declining activity. Visible deposits, discolouration or mechanical damage found during inspection complete the picture. Not every loss of performance means replacement: fouling can often be remedied by cleaning or regeneration, whereas poisoning usually cannot. Send us current measured values, differential pressure trends and photos of the elements, and we will assess the condition of your catalyst.
It is not possible to give a general figure, because the duration depends on several factors. Preparation has the greatest influence: if the dimensions, design and support frames of the existing housing are known, the replacement elements can be manufactured or sourced in advance, and the actual exchange on site is limited to removal, installation and testing. For housings from other manufacturers without complete documentation, the housing first has to be measured. On site, the accessibility of the housing, the cooling time of the plant, the size and weight of the elements, the lifting equipment required and the condition of seals and frames all play a role. In SCR systems, work on the dosing equipment may also be needed. To keep downtime short, it is advisable to combine the replacement with maintenance work already planned on the engine or process plant. Send us the type plate, a housing drawing or photos and details of accessibility, and we will plan the replacement together with you.
The maintenance interval depends heavily on the mode of operation and the composition of the exhaust gas. With clean exhaust gas, for example from a natural gas CHP unit, an annual inspection is often sufficient. For demanding processes with dust or potential catalyst poisons, such as biogas or industrial process exhaust air, a check every six months is advisable. Regular measurement of the differential pressure and the conversion rate helps to detect fouling early, before emission limits are exceeded.
That depends on your permit, the regulation that applies to your plant and the type of change. Replacing catalyst elements with equivalent ones as part of maintenance is assessed differently from a modification in which the design, construction or cleaning process changes. In the latter case, notification of or consultation with the authority may be required, often combined with a measurement that demonstrates compliance with the emission requirements. Even where no measurement is mandatory, a check measurement can be useful to document the effect of the new elements and provide a baseline for later comparisons. It is best to clarify the requirements early with your authority or your measuring body so that the replacement and the measurement date can be coordinated. Technical documentation on the installed catalyst elements is helpful for this coordination. Let us know which evidence your authority requires, and we will align the documentation for the replacement accordingly.
Regenerating SCR catalysts restores their full denitrification performance (NOx reduction) when the catalyst is blocked by deposits such as ammonium sulphate or dust. Special thermal or chemical processes remove these blockages. Regeneration conserves resources, avoids the purchase of expensive new modules and ensures that the plant once again operates with low ammonia or AdBlue consumption and at its intended efficiency.
Catalyst poisoning occurs when certain chemical elements bind irreversibly to the active surface of the catalyst and permanently impair its function. Typical catalyst poisons in industry and in biogas plants are sulphur, silicon (siloxanes), phosphorus, lead and other heavy metals. While ordinary fouling can be washed off, genuine catalyst poisoning usually means that the affected catalyst elements have to be replaced.
After long shutdowns, for example due to seasonal operation, overhauls or production breaks, moisture can condense in the catalyst and the exhaust gas path. Together with deposits from operation, this can form acids or salts that affect the catalyst. When restarting, the system should therefore be heated up as evenly as possible so that condensate can evaporate and no thermal stresses develop in the elements. In SCR systems, reducing agent dosing should only be enabled once the minimum temperature at the catalyst has been reached, as deposits can otherwise form. Before start-up, it is worth checking seals, measuring points and dosing lines, especially if the plant was shut down over the winter. Monitor the differential pressure and temperatures during the first hours of operation to detect anomalies early. If you regularly have long shutdowns, start-up and preservation steps can be set out in an operating instruction. Contact us if you would like support in assessing your plant.
First, evaluate the measurement report carefully: which component exceeded the limit, under which load condition and by how much? Also inform the competent authority if your permit or the applicable regulation requires this, and clarify the next steps and the deadline for a repeat measurement with them. On the technical side, it is worth looking at the causes systematically. Common reasons include an aged or fouled catalyst, incorrect engine or burner settings, faulty reducing agent dosing in SCR systems or a catalyst that is undersized for the operating conditions. Differential pressure, temperatures upstream and downstream of the catalyst and operating hours provide important clues. Depending on the findings, cleaning or regeneration may be sufficient; in other cases, the elements need to be replaced or the design adjusted. Send us the measurement report and the key plant data via our page for urgent cases. You will usually receive initial feedback within 24 hours.
Retrofit and Replacement Elements 8
In many cases, yes. Whether and how a retrofit is possible depends mainly on three factors: the space available in the flue gas path, the temperature at the intended installation point and the dust load. If the temperature downstream of the dust filter is too low, a heat exchanger or auxiliary heating may be required. A storage and dosing system for the reducing agent, usually urea solution, is also needed, together with a control system that adjusts the dosing rate to the load. In heating plants with strongly fluctuating heat demand, this load behaviour is a central aspect of the design. Existing components such as filters, induced draught fan and stack are included in the planning and reused wherever possible. For an initial assessment, a layout drawing or photos of the flue gas path, details of the thermal output and fuel, and the latest emission measurement report are helpful. With these documents, we can check which retrofit option is technically appropriate for your plant.
Yes, many systems can be retrofitted or optimized with catalytic systems. A precise analysis of the exhaust air flows is crucial in order to integrate the right solution.
Yes, retrofits are a typical application, especially to adapt existing press and dryer lines to tightened emission limits.
Yes, that is one of our core competencies. We analyze your existing system and integrate state-of-the-art catalyst technology into existing housings to reduce investment costs.
Absolutely. We manufacture or source high-performance components that can be seamlessly integrated into enclosures from other manufacturers, often with better performance than the original.
Replacing catalyst elements does not require replacing the entire housing. After the existing system has been measured and analysed, precisely fitting replacement catalysts, for example in honeycomb or plate form, are produced. These elements are matched to the existing support frames of the third-party housing and exchanged on site. In many cases, this even allows the cleaning performance to be improved within the same installation space.
It is not possible to give a general figure, because the duration depends on several factors. Preparation has the greatest influence: if the dimensions, design and support frames of the existing housing are known, the replacement elements can be manufactured or sourced in advance, and the actual exchange on site is limited to removal, installation and testing. For housings from other manufacturers without complete documentation, the housing first has to be measured. On site, the accessibility of the housing, the cooling time of the plant, the size and weight of the elements, the lifting equipment required and the condition of seals and frames all play a role. In SCR systems, work on the dosing equipment may also be needed. To keep downtime short, it is advisable to combine the replacement with maintenance work already planned on the engine or process plant. Send us the type plate, a housing drawing or photos and details of accessibility, and we will plan the replacement together with you.
The cost of a retrofit depends largely on the size of the plant, the exhaust gas flow rate and the emission limits to be met. In general, modernising an existing system is considerably more cost-effective than a complete new installation. Because existing housings, pipework and infrastructure continue to be used, both the hardware investment and the production downtime during the conversion are reduced.
CHP and Biogas 9
Yes, the performance of a catalytic converter can be impaired by ageing or impurities (e.g. sulphur, siloxanes). Regular monitoring and maintenance are therefore crucial for a permanently high separation efficiency.
Catalysts specifically reduce critical pollutants such as VOCs, CO and formaldehyde. This ensures that emission limits are reliably complied with – even under varying operating conditions.
Catalytic systems enable the oxidation of pollutants at significantly lower temperatures. This reduces energy consumption, lowers operating costs, and allows for a more compact system design.
The 44th BImSchV sets stricter emission limits for existing and new medium combustion plants, gas turbines and combustion engines (CHP). For existing plants, staggered transition periods apply depending on rated output and fuel type before the new limits for nitrogen oxides (NOx), carbon monoxide (CO) and formaldehyde must be met. Operators often have to retrofit their plants with SCR systems or oxidation catalysts in order to reliably achieve the required values and avoid losing their operating permit.
In addition to CO₂ and water vapor, nitrogen oxides (NOₓ), carbon monoxide (CO) and unburned hydrocarbons – in particular VOCs and formaldehyde – are also produced during operation. The level of emissions depends heavily on the gas quality and combustion efficiency.
Ammonia slip refers to ammonia that passes through the SCR catalyst unused and is released into the environment with the exhaust gas. It occurs when more reducing agent is dosed than can react with nitrogen oxides on the catalyst. Causes include overdosing, uneven distribution of the reducing agent across the exhaust gas cross-section, exhaust gas temperatures that are too low, rapid load changes or a catalyst whose activity has declined. Ammonia slip is undesirable for several reasons: ammonia is itself an air pollutant, it can form deposits in combination with sulphur compounds, and it means unnecessary consumption of urea solution. It can be avoided with load-dependent dosing control, a sufficient mixing section upstream of the catalyst, an appropriate catalyst design and regular checks of the dosing equipment. In addition, a downstream oxidation catalyst can convert remaining ammonia. If your measurement reports show ammonia or your urea consumption is rising, send us the data so that we can assess the dosing and catalyst condition together with you.
Catalytic converters are usually installed in the exhaust tract downstream of the engine. Depending on the system, oxidation catalytic converters or combined solutions are used, which are specially adapted to the composition of biogas.
Two types of catalyst are mainly used in biogas CHP units: oxidation catalysts to reduce formaldehyde and carbon monoxide (CO), and SCR catalysts where a substantial reduction of nitrogen oxides (NOx) is required. As biogas often contains traces of hydrogen sulphide and siloxanes, the catalysts must either be designed to be particularly robust or be protected upstream by suitable gas cleaning systems such as activated carbon filters.
Biogas is not a fuel with a constant composition. Fluctuations in methane content or impurities can lead to incomplete combustion – and thus to increased VOC emissions. These must be treated in a targeted manner in order to comply with limit values.
Industrial Painting and Curing 6
Yes, many systems can be retrofitted or optimized with catalytic systems. A precise analysis of the exhaust air flows is crucial in order to integrate the right solution.
As catalytic oxidation takes place at lower temperatures, less energy is required for exhaust air purification. This can significantly reduce operating costs and improve the overall energy efficiency of the system.
Catalytic converters are particularly efficient at medium VOC concentrations and constant exhaust air flows. They offer advantages when the focus is on energy efficiency and operating costs.
In addition to catalytic systems, thermal post-combustion (RTO), adsorption (e.g. activated carbon) or combinations of these processes are also used. The choice depends on the volume flow, VOC concentration and process conditions.
The highest VOC emissions typically occur during paint application, flash-off and thermal curing. Continuous exhaust air flows from drying ovens are particularly critical.
Paints often contain solvents that are released as VOCs when they evaporate. These are harmful to the environment and health and are subject to strict legal requirements, which makes effective exhaust air purification absolutely essential.
Chemical Industry 5
Yes, substances such as silicones, heavy metals, sulphur or halogen compounds can affect catalysts. Pure Air therefore carries out detailed gas analyses in advance and uses targeted pre-filters, guard beds or catalyst types with resistant doping.
In principle, yes, but this type of exhaust air places special demands on the system. Chlorinated or fluorinated hydrocarbons can be oxidised on suitable catalysts. In addition to carbon dioxide and water, this produces acid gases such as hydrogen chloride or hydrogen fluoride. This has three consequences for planning. First, the catalyst type and support material must be resistant to halogens, as standard coatings can be deactivated by them. Second, materials for the housing and pipework must be selected to withstand the acidic reaction products, particularly where the temperature may fall below the dew point. Third, a scrubber is usually required downstream of the catalyst to remove the acid gases. It must also be checked whether undesirable by-products can form under the operating conditions. A reliable design therefore requires detailed knowledge of the exhaust air composition. Provide us with substance lists, concentration ranges and process descriptions so that we can assess whether a catalytic process is suitable.
With careful engineering and preheating sections, catalytic systems can respond flexibly to peak loads and load changes without loss of efficiency or thermal overload.
Catalytic processes operate at much lower temperatures (often 250 to 450 °C compared with more than 800 °C for an RTO). This saves a considerable amount of fuel, reduces the carbon footprint and requires less installation space.
Catalytic systems deliver consistent cleaning performance regardless of weather, microbial load or biological activity, and they require no water or sludge treatment.
Printing and Packaging 3
In printing presses, solvents are released at several points: at inking units, dryers, laminating units and into the hall air. Targeted capture at the sources is important for economical catalytic treatment, because the higher the solvent concentration in the exhaust air, the less additional energy the catalyst requires. A common approach is recirculation in the dryers, where part of the dryer air is returned and the concentration increases as a result. For large flow rates with low concentrations, upstream concentration, for example with an adsorption wheel, can make sense. For safety reasons, the concentration must always remain well below the lower explosive limit, which is monitored by measuring equipment. Changing print jobs and downtime at individual presses also influence the design. Send us the number and type of presses, the solvents used and any existing exhaust air measurements, and we will check how your exhaust air can be captured and treated effectively.
The 31st BImSchV regulates emissions of volatile organic compounds from installations that use solvents, for example in printing, painting or packaging production. Operators covered by the regulation must document their solvent flows in a solvent management plan, also known as a solvent balance. It compares the solvents fed into the installation with where they end up: in the product, in waste, in the captured and treated exhaust air or as fugitive emissions via room air and windows. The authority uses this balance as evidence that the requirements of the regulation are being met. Catalytic exhaust air treatment has a direct effect on this balance, as it reduces the share of captured solvents that actually reach the environment. The better the capture at the machines, the lower the fugitive share. If you provide your current solvent management plan and details of your exhaust air ducting, we can assess the contribution that exhaust air treatment can make.
Catalytic exhaust air treatment is required or economically sensible in all industries that release volatile organic compounds (VOCs). These include industrial painting and coating lines, the chemical industry, printing and packaging companies (flexographic and gravure printing), woodworking (gluing and drying) and the plastics processing industry. Treating the exhaust air protects the environment and prevents odour nuisance in the neighbourhood.
Wood Firing and Biomass 3
In many cases, yes. Whether and how a retrofit is possible depends mainly on three factors: the space available in the flue gas path, the temperature at the intended installation point and the dust load. If the temperature downstream of the dust filter is too low, a heat exchanger or auxiliary heating may be required. A storage and dosing system for the reducing agent, usually urea solution, is also needed, together with a control system that adjusts the dosing rate to the load. In heating plants with strongly fluctuating heat demand, this load behaviour is a central aspect of the design. Existing components such as filters, induced draught fan and stack are included in the planning and reused wherever possible. For an initial assessment, a layout drawing or photos of the flue gas path, details of the thermal output and fuel, and the latest emission measurement report are helpful. With these documents, we can check which retrofit option is technically appropriate for your plant.
Flue gas from wood and biomass combustion contains fly ash that can block channels and cover active surfaces. Wood ash also contains alkali metals such as potassium, which gradually deactivate SCR catalysts. The most important protection is effective dust removal upstream of the catalyst. In addition, catalysts with a larger cell pitch or plate-type elements are used, as they are less prone to clogging, and cleaning devices such as soot blowers or compressed air pulses are installed. The position in the flue gas path also matters: placing the catalyst downstream of the dust filter relieves it but may require the flue gas to be reheated. During operation, a rising differential pressure is an early sign that deposits are forming. In many cases, fouled elements can be cleaned or regenerated before replacement becomes necessary. Send us details of the fuel, the filter technology and the flue gas temperatures, and we will assess which protective measures make sense for your plant.
Burning wood, wood chips, pellets or residues produces dust and, above all, nitrogen oxides (NOx), carbon monoxide (CO) and unburnt organic compounds. Nitrogen oxides can be reduced with an SCR catalyst and a reducing agent, while CO and organic components are treated with an oxidation catalyst. Dust itself is not removed catalytically but separated by cyclones, fabric filters or electrostatic precipitators. Which combination makes sense depends on the fuel, the combustion technology, the load profile and the requirements in your permit. The temperature window and dust removal are often the deciding factors in the design, because the catalyst must be located at a point in the flue gas path where the temperature is suitable and the dust load is manageable. If you send us the fuel type, the thermal output and a recent emission measurement report, we will assess which catalyst technology is suitable for your plant.
Woodworking and Wood-Based Panels 3
That depends on the moisture and pollutant profiles. Exhaust air streams are often thermally preconditioned or captured separately so that the catalyst operates within its optimum range.
Yes, retrofits are a typical application, especially to adapt existing press and dryer lines to tightened emission limits.
Formaldehyde-based binders are used in the production of particleboard, MDF and OSB. In the press and while the boards cool, formaldehyde and other organic compounds enter the exhaust air, often together with wood dust, resin aerosols and a high moisture content. For catalytic oxidation of this exhaust air, pretreatment comes first: dust and sticky aerosols must be removed to the extent that they cannot clog the catalyst. The exhaust air is then brought to the required reaction temperature, often supported by heat exchangers that recover energy from the cleaned gas. Because press exhaust air has large flow rates at comparatively low concentrations, the energy balance is an essential part of the design. The temperature profile must also be chosen so that no condensate forms in the system. If you send us the flow rate, exhaust air temperature, measured values for formaldehyde and total carbon and details of the dust removal, we will check a suitable concept for your press.
Food Industry 3
Yes, this is often possible and is considered during the design phase. In catalytic oxidation, organic substances in the exhaust air are converted into carbon dioxide and water vapour. This releases reaction heat, and the cleaned gas leaves the catalyst at a higher temperature. This heat can be used via a heat exchanger, for example to preheat the exhaust air to be treated, to produce hot water or thermal oil, or to support drying and roasting processes. How much heat can usefully be recovered depends on the pollutant concentration, the flow rate, the operating hours and whether there is a suitable heat consumer on site. In plants with frequent downtimes or frequently changing recipes, the balance looks different from that of continuous operation. If you provide us with your exhaust air data and your heat demand, we will check whether heat recovery makes technical and economic sense for your process.
As a rule, yes. Exhaust air from frying, roasting and smoking equipment contains not only gaseous odour compounds but also fat and oil droplets and soot particles. If these reach the catalyst unfiltered, they clog the surface, can carbonise and noticeably reduce the cleaning performance. For this reason, pre-separation is usually planned upstream of the catalyst, for example with grease filters, aerosol separators or thermal pretreatment. The right solution depends on the fat load, the exhaust air temperature and the cleaning effort you can manage in day-to-day operation. Maintenance access to the filters should also be considered from the outset so that filter changes and cleaning can be carried out without major effort. If a catalyst is already coated with fat or oil residues, chemical cleaning can often restore its activity. Describe your process, production hours and existing exhaust air ducting to us, and we will check which pre-separation suits your plant.
Roasting, baking, frying and smoking processes in the food industry release strongly smelling organic compounds and fat aerosols. Catalytic exhaust air treatment breaks down and oxidises these odour-intensive hydrocarbons at low temperatures. The result is process exhaust air that is largely odour-neutral and compliant with regulations, which helps to avoid conflicts with neighbours and authorities.
