Tire pyrolysis gas contains useful energy, but it is not ready to enter a gas engine as soon as it leaves the reactor. The raw gas can be hot and may carry oil vapor, tar, moisture, sulfur compounds and fine particles. Its pressure and composition may also change during the pyrolysis cycle.
Without suitable treatment, these contaminants can collect in pipes, restrict valves, interfere with combustion and increase engine wear. Even when the gas continues to burn, the generator may produce less power, require more maintenance or stop unexpectedly.
Effective tire pyrolysis gas treatment is therefore the connection between the pyrolysis reactor and reliable power generation. The treatment system should cool and clean the gas while maintaining enough pressure and fuel value for the generator. Its design must be based on the actual gas rather than on a standard equipment list copied from another plant.
Why Raw Tire Pyrolysis Gas Cannot Enter the Engine Directly
Tire pyrolysis takes place in an oxygen-limited reactor where rubber is heated and broken into gas, oil, recovered carbon material and steel. The gas leaving this process is not comparable to clean pipeline natural gas.
Part of the vapor stream becomes pyrolysis oil when it cools. Other heavy compounds may remain as tar or fine droplets. Water vapor can condense inside the piping, while dust and carbon particles may travel with the gas. Depending on the feedstock and process, sulfur compounds can also be present.
If raw gas enters the engine, tar may deposit on valves, fuel-system parts, turbochargers and combustion surfaces. Moisture can encourage corrosion and disturb combustion. Particles can increase wear or contaminate lubricating oil. Sulfur compounds may damage components and make exhaust control more difficult.
These problems do not always cause an immediate shutdown. A plant may first experience unstable output, rising exhaust temperature, higher gas consumption or shorter maintenance intervals. This is why gas cleaning should be treated as part of the power system rather than as an optional accessory.
KLY’s tire pyrolysis gas generator set range is intended for industrial projects that recover combustible gas from waste-tire pyrolysis. Before a generator can be selected, the raw gas condition and the treatment required to protect the engine must be understood.
Start With a Complete Gas Analysis
There is no single treatment line that suits every tire pyrolysis plant. Reactor design, operating temperature, tire composition and condensation efficiency all affect the gas reaching the generator area.
A laboratory analysis should identify both the combustible components and the contaminants. Methane, hydrogen, carbon monoxide and light hydrocarbons influence heating value and combustion behavior. Carbon dioxide, nitrogen and other non-combustible components dilute the fuel. Tar, particles, sulfur and moisture determine the cleaning process.
One sample taken during the strongest gas-production period is not enough. The supplier should also understand how the gas changes during startup, normal production and shutdown. This is especially important for batch plants, where gas flow and calorific value may vary through the cycle.
Gas data | Why it is needed |
Lower heating value | Helps estimate gas demand and available electrical output |
Gas composition | Determines combustion behavior and engine settings |
Hourly flow range | Shows whether the fuel supply can support continuous generation |
Temperature and pressure | Influence cooling, piping and gas-train design |
Tar content | Determines the required condensation and tar-removal process |
Moisture level | Defines cooling, separation and drainage requirements |
Sulfur compounds | Determine whether desulfurization is needed |
Particle content | Helps specify filtration stages |
Variation during operation | Supports buffer sizing and control-system design |
A good gas analysis does more than confirm that the gas is combustible. It gives the treatment-system designer the information needed to produce fuel that the engine can use consistently.
The Main Stages of Tire Pyrolysis Gas Treatment
A typical tire pyrolysis gas purification system may include several stages, but their order and capacity depend on the raw gas. The objective is to remove harmful material without losing excessive fuel energy or creating a large pressure drop.
Gas Cooling and Condensation
The gas leaving the pyrolysis process is normally too hot for direct use in an engine. Controlled cooling lowers its temperature and condenses oil vapor, water vapor and some heavy hydrocarbons.
This stage must be designed carefully. Insufficient cooling allows excessive condensable material to remain in the gas. Poorly controlled cooling can also create liquid accumulation in pipelines or cause valuable gas components to condense unnecessarily.
Heat exchangers, condensers and cooling-water systems should be sized for the maximum gas flow and the local climate. Drain points and liquid collection equipment must be placed where condensed oil and water can be removed safely.
Cooling also needs to remain stable throughout operation. If the outlet temperature changes widely, the amount of moisture and oil carried into the next treatment stage will also change.
Liquid Separation
After cooling, the condensed liquid must be separated from the gas stream. A separator or knockout vessel allows droplets to fall out before the gas continues downstream.
The drainage system is just as important as the vessel itself. If liquid is allowed to collect, it can be carried forward during a pressure change or high-flow period. Automatic level monitoring and reliable drainage can reduce this risk.
The separated liquid may contain both water and hydrocarbons, so it should be handled according to the plant’s waste and product recovery plan. It should not be allowed to return uncontrolled to the gas piping.
Particle Filtration
Fine carbon material, rust and other solid particles can travel through the gas system. Filtration helps prevent these particles from reaching valves, pressure regulators and engine components.
A single fine filter placed at the end of the line is not always the best solution. If the raw gas carries a high particle load, the filter may block quickly and create a pressure drop. A staged system can remove larger particles first and use finer filtration closer to the generator.
Pressure readings before and after the filter help operators identify when cleaning or replacement is required. Without this information, a blocked filter may appear to be a generator fuel problem.
Tar Removal
Tar is one of the most important concerns in pyrolysis gas treatment for power generation. It can remain as vapor at high temperature and then condense as the gas cools further inside piping or engine components.
Tar removal may involve controlled condensation, separation, scrubbing or another process selected according to the tar concentration and composition. The correct method depends on whether the material is mainly heavy oil droplets, vapor-phase compounds or a mixture of both.
The target should be based on the engine supplier’s allowable gas specification. An arbitrary “tar-free” claim is less useful than a measured outlet concentration obtained under normal operating conditions.
Desulfurization
Waste-tire feedstock contains sulfur-bearing materials, so the resulting gas may require desulfurization before entering the engine. The concentration and form of the sulfur compounds determine the suitable treatment method.
A desulfurization system must be sized for both average and peak sulfur loading. If it is designed only around an average sample, sudden increases may allow untreated gas to pass through. On the other hand, an unnecessarily complex system can increase capital cost, pressure loss and operating demand.
Buyers should ask for the expected inlet concentration, outlet target, treatment capacity, consumable requirements and method used to monitor breakthrough.
Final Filtration and Gas Conditioning
After the main contaminants have been removed, the gas normally passes through a final filtration and conditioning stage. This helps capture remaining droplets or particles and prepares the fuel for the gas train.
At this point, temperature, pressure and flow should be within the required operating range. The system may also include flame arresters, shutoff valves, leak detection and instruments that prevent unsuitable gas from entering the engine.
The final result should not simply be “cleaner gas.” It should be gas that meets measurable engine inlet requirements.
Why Gas Storage and Pressure Control Matter
Gas cleaning alone cannot correct every fuel problem. A pyrolysis reactor and a generator set may not consume gas at the same rate.
During periods of strong gas production, supply may exceed engine demand. At another point in the cycle, the gas flow may fall below the amount needed to maintain output. Starting and stopping the generator each time the flow changes can reduce availability and increase mechanical stress.
A properly designed buffer or gas-storage arrangement can smooth short-term differences between production and consumption. Pressure regulation then supplies the generator within its required inlet range.
The storage volume should not be selected by guesswork. It depends on the hourly gas-production profile, generator consumption, allowed pressure range and acceptable operating time during a supply dip.
The complete design must also include gas detection, overpressure protection, safe venting or alternative gas use, and emergency isolation. Gas storage should never be viewed only as a way to improve efficiency; it is also a major safety component.
How Treatment Design Affects Power Generation Efficiency
A stronger purification system does not automatically produce a more efficient plant. Every blower, pump, cooler and scrubber consumes energy. Filters, vessels and long pipelines also create pressure loss.
If the treatment system removes contaminants but delivers gas at insufficient pressure, the engine may still fail to reach the required load. If cooling equipment consumes excessive power, gross generator output may appear satisfactory while net plant output remains low.
An efficient design balances three objectives:
Protect the engine from contaminants.
Deliver stable gas within the required pressure and temperature range.
Keep auxiliary power demand and fuel loss under control.
The most useful calculation is the net power available after the energy used by the pyrolysis line, gas-treatment equipment, cooling system and other plant auxiliaries has been deducted.
This whole-system view prevents buyers from comparing treatment equipment only by purchase price or comparing generators only by rated efficiency.
Matching Treated Gas to the Generator Set
Treatment targets should come from the generator’s fuel requirements. The engine supplier needs to define acceptable limits for calorific value, pressure, temperature, moisture, particles, sulfur and tar.
The importance of gas quality is clear in KLY’s 16V190G Gas Generator Set. Its published rated-power range is 750–1250kW, and the available output is specified according to gas quality. This means the nameplate range cannot be separated from the fuel supplied to the engine.
KLY’s 12V190G Gas Generator Set covers a published power range of 500–1000kW. The product information lists a defined gas inlet pressure and notes adaptability to biogas and low-concentration industrial gases in addition to natural gas.
These products provide useful reference points for understanding industrial gas-engine requirements, but neither model should be assumed to accept untreated tire pyrolysis gas. Compatibility and available output must be confirmed from the project’s gas composition, purification results and operating conditions.
A treatment system should therefore be designed together with the generator fuel system. Designing the purifier first and selecting an engine later can leave a gap between the gas delivered and the gas the engine requires.
Safety and Monitoring Requirements
Tire pyrolysis gas contains flammable components and may also contain carbon monoxide. Leaks can create fire, explosion and poisoning risks, especially in enclosed spaces.
The gas line should include suitable detection, ventilation, isolation and emergency shutdown measures. Depending on the project, instruments may monitor pressure, temperature, flow, gas composition and contaminant levels.
Online monitoring does not replace laboratory testing, but it helps operators recognize a change before it becomes an engine problem. For example, a pressure drop across a filter may signal blockage, while a sudden temperature change after the condenser may indicate a cooling-system problem.
Alarm and shutdown values should be coordinated across the pyrolysis system, gas-treatment line and generator. If each system operates independently, one part of the plant may continue feeding gas after another part has stopped.
What Buyers Should Provide Before System Design
A supplier cannot design reliable tire pyrolysis gas treatment from the desired generator capacity alone. Buyers should provide representative gas data, the process flow and site operating requirements.
The technical enquiry should state:
Pyrolysis reactor type and processing capacity
Batch, semi-continuous or continuous operation
Gas composition and lower heating value
Average, minimum and maximum gas flow
Gas temperature and pressure
Tar, moisture, sulfur and particulate levels
Number of operating hours per day
Desired electrical output
Site altitude and ambient temperature
Required voltage and frequency
Local emission and safety requirements
Existing cooling-water and utility conditions
When raw gas data are incomplete, sampling and testing should take place before final equipment selection. Estimates may be useful during early planning, but they should not become the basis of the final performance guarantee.
KLY’s one-stop gas power services cover the wider project process, allowing gas treatment, generator selection and system integration to be considered together.
Frequently Asked Questions
What is the most important treatment for tire pyrolysis gas?
There is no single most important stage for every project. Tar, moisture, sulfur and particles can all cause problems. The gas analysis and engine inlet specification should determine which treatment stages are required.
Does tire pyrolysis gas always need desulfurization?
It depends on the sulfur concentration in the raw gas and the limits of the selected engine and emission system. Because tire materials can contain sulfur, testing is necessary before deciding whether desulfurization is required and how large the system should be.
Why must pyrolysis gas be cooled before entering a generator?
Cooling lowers the gas temperature and helps condense oil vapor, water and heavy hydrocarbons. These liquids can then be separated instead of entering the engine or condensing later in the piping.
Can filtration alone remove tar?
A particle filter is not always sufficient because part of the tar may remain as vapor or fine liquid droplets. Tar control often requires cooling, condensation or another treatment stage before final filtration.
How clean should tire pyrolysis gas be?
The required outlet quality depends on the selected generator. Buyers should request measurable limits for tar, particles, moisture, sulfur, gas temperature and inlet pressure from the engine supplier.
Can treated pyrolysis gas be used in a standard natural gas generator?
Not automatically. Even after purification, the gas may differ from natural gas in composition, calorific value and combustion behavior. The engine and control system must be evaluated and configured for the treated fuel.
Conclusion
Successful tire pyrolysis power generation depends on more than producing combustible gas. The gas must reach the generator at a suitable temperature, pressure and quality while remaining stable enough for controlled combustion.
A complete tire pyrolysis gas treatment system may include cooling, condensation, liquid separation, filtration, tar removal, desulfurization, final polishing and pressure regulation. The correct combination depends on laboratory gas data, the pyrolysis process and the selected engine.
The treatment line and generator should therefore be designed as one system. When gas analysis, purification targets, storage, engine requirements and monitoring are coordinated from the beginning, the plant has a stronger foundation for stable output, lower maintenance demand and long-term industrial operation.
