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**MEMORANDUM**

**TO:** Melanie King, Environmental Protection Agency

**DATE:** April 9, 2010

**RE:** Extended Intervals and Consistency for Spark Ignite d RICE

Management Practices

**SPARK IGNITED ENGINE EXTENDED AND CONSISTENT INTERV AL JUSTIFICATION** 

This memorandum was prepared to support the collect ive comments of Exterran, JW Power and CSI ("EJC Coalition") previously submitted on June 3, 2009 and advocates for longer intervals and consistency when applying management practices to S park Ignited Reciprocating Internal Combustion Engines ("SI RICE") at area sources. On March 3, 2010, EPA issued the National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; Final Rule (“diesel rule”), for diesel-fueled Compression Ign ited ("CI") RICE. EPA included bifurcated management practices for diesel engines located at area sources of hazardous air pollutant (“HAP”) emissions. An interval period of 1,000 hours was established to inspect the oil and air filter. A second interval period of 50 0 hours was established to inspect the belts and hoses. Based upon the cleaner-burning combustion p roperties of SI RICE and the practicalities of inspecting rural, unmanned engines, EPA should e stablish a single, consistent management practice intervals for all SI RICE management pract ices based up engine type, e.g. , 1,440 hour interval period for rich burn SI RICE and 4,320 hou rs for lean burn SI RICE.

Further information supporting the longer, consist ent intervals is provided below. For the sake of efficiency, this addendum supplements b ut does no repeat the SI RICE management practice recommendations submitted to EPA on Januar y 27, 2010.

**SI RICE Extended Intervals**

The longer inspection intervals for SI RICE are ju stified because of the cleaner-burning characteristics of natural gas. For example, liqui d fuels such as diesel and gasoline contain significant proportions of carbon, sulphur, and nit rogen. When diesel enters the combustion chamber the liquid fuels wash the lubricant from th e cylinder walls causing dilution and carbon particles or soot is formed. The carbon deposits/p articles deplete the engine oil additives thus shortening the oil life. The combination and accum ulation of these oil contaminants (unburned2

fuel, ash, and acids) accounts for the potential br eakdown of the lubricant thus potentially accelerating the engine oil contamination and decre asing the effectiveness of the oil lubrication.

Natural gas is a cleaner-burning gaseous fuel free from the liquid hydrocarbons that can potentially cause the accelerated oil contamination discussed above. Due to the cleaner burning, gaseous nature of natural gas, the by-prod ucts of combustion (carbon particulates and ash) are significantly reduced which slows the rate in which contaminants are released into the engine oil. As a result, it is reasonable to expec t an increased oil change/analysis interval of 1,440 hours for rich-burn SI RICE located at area s ources of HAP emissions.

As discussed in the January 27th Management Practi ce submittal, the engine configuration of the Ajax 2-stroke lean burn (2SLB) RICE allows for an even greater extended inspection interval for both spark plugs and oil in spections. Ajax 2SLB RICE have an extended inspection interval because the power cylinder is s eparated from the crankcase and uses a sealed piston rod for the mechanical connection. D ue to this engine configuration, no combustion blow-by products get into the crank case to contaminate the oil. Ajax 2SLB are also slow speed, lower combustion engines, which means t hat the spark plug fires less than and at a lower temperature than a typical 4SRB or 4SLB engin e, thus allowing extended intervals for the spark plugs.

**Interval Consistency**

Finally, we request that any SI RICE Management Pr actice intervals be consistent across all inspections. Bifurcated inspection intervals w ill create excessive trips to remote area sources which increase costs and vehicle emissions but do not provide a corresponding environmental benefit. Creating a consistent inspe ction interval for all management practices eliminates the unnecessary trips.

In lieu of belts and hose inspection, the SI RICE M anagement Practice recommendations submitted on January 29, 2010 included proposed int ervals for spark plug inspections and replacements

**.** Visual inspection of the firing ends of each cylind er's spark plug can suggest a variety of possible engine conditions. For example , a visual inspection of a spark-plug firing end may identify oil or carbon fouling which indicates an engine component is experiencing high temperature or excessive wear. If the spark plug i s fouled it can be cleaned, regapped and returned to service. If the spark plug is worn, cr acked or otherwise damaged then replacement is necessary.

Although preventative maintenance standards requir e that belts and hoses be inspected, c urrent maintenance and operating practices do not i ndicate that an increased frequency of belt or hose inspections reduce emissi ons. In fact, should a faulty belt or hose fail,3

the engine will shut down, therefore preventing in creased emissions.

Any inspection interval for spark plugs (or belts and hoses) should be consistent with other inspection interval periods on SI RICE. As s ubmitted in the June 8, 2009 comments to EPA on the SI RICE, a majority of the SI RICE are locat ed at rural, remote, unmanned locations. This is particularly true for area sources. Management practice intervals should be consistent to prevent excessive staffing, vehicle trips, and cost s which do not improve engine performance or reduce emissions.