PARAMETRIC EMISSION MONITORING SYSTEMS AS AN ALTERNATIVE TO CONTINUOUS EMISSION MONITORING SYSTEMS ON LANDFILL GAS-FIRED ENGINES

摘要

An increasing number of landfill gas-to-energy projects are being required by local and state air permitting agencies to install continuous emissions monitoring systems (CEMS) for NO_x emissions. An alternative to CEMS that is allowable in many jurisdictions is a parametric emissions monitoring system (PEMS). A PEMS uses measurements of physical parameters such as air/fuel ratio, load, cylinder pressure and temperature to calculate NO_x emissions. In most cases, a PEMS can be installed and operated more economically than a CEMS. Additionally, a PEMS typically does not require the instrumentation skills necessary to operate and maintain a CEMS. This is important for landfill gas-to-energy facilities where there are typically small on-site staffs. This paper provides a general overview of PEMS, a review of regulatory issues, and specifically focuses on the potential for Caterpillar's G3600 engine series control system to serve as a PEMS for landfill gas-to-energy facilities. Information on US EPA policies and regulations regarding PEMS as well as policies from selected state and local agencies is included. Basic information is provided regarding the air-fuel ratio control system on the G3520C and G3616 engine-generator set. Combustion and operating controls on these engines are designed specifically to meet target NO_x emission levels, and the feasibility of using this information for a PEMS is discussed. Data from the Los Angeles County Sanitation Districts' engine facility at the Puente Hills Landfill is presented. This plant, scheduled to start up in January 2006, has three Caterpillar G3616 engine-generator sets installed with certified CEMS. NO_x data generated by the Caterpillar engine control system will be compared to CEMS data to help evaluate the feasibility of using this system as a PEMS.