Rich-burn or lean-burn stationary gas engines can comply with the most stringent air pollution limits when equipped with Johnson Matthey catalytic emission control systems.
Stationary gas engines are most often used when fuels such as pipeline natural gas, syngas, biogas and LPG are economically attractive. Gas-powered stationary engines are ideal for prime power generation, combined heat and power plants, oilfield power applications such as drilling and enhanced oil recovery, gas compression and liquid pumping stations. Utilization of biogas from farms, landfills and water treatment plants requires gas or diesel engines that have been converted to operate on gaseous fuels.
Rich-burn engines
Rich-burn gas engines operate at or near the stoichiometric air to fuel ratio (AFR) and have exhaust oxygen concentrations < 0.7%. The three-way catalyst (TWC) is used to prevent air pollution from rich-burn engines. Johnson Matthey's three-way catalysts and three-way catalytic converters offer the ultimate in both flexibility and durability. The three-way catalyst is contained in a single, durable catalyst housing, and is available either as a ready to install module or customized.
Lean-burn engines
Lean-burn gas engines operate with a higher AFR, therefore, the oxygen concentration in the exhaust is much higher. To control air pollution from lean-burn engines, selective catalytic reduction (SCR) catalyst is used for NOx reduction and oxidation catalysts are used to reduce hydrocarbon and carbon monoxide emissions. When the SCR catalyst is coupled with our unique, highly selective Ammonia Slip Catalyst (ASC), NOx reduction is enhanced and ammonia, hydrocarbon, formaldehyde and carbon monoxide emissions are reduced as well. For lean-burn gas engines that are factory compliant with applicable NOx standards but need CO and hydrocarbon emission control, oxidation catalysts are utilized. The Johnson Matthey oxidation catalyst is supplied in a single robust housing that is ready to install or available for customization if needed.
Typical emission and noise reductions achievable for gas engines equipped with converter and silencer.
| Engine Type | NOx | CO | HC | Noise |
| Rich Burn | 80%-99% | 80%-99% | 80%-99% | 25-35 db(A) |
| Lean Burn | 80%-95% | 70%-98% | 70%-95% | 25-35 db(A) |
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