Integrated Utility Improvement Project Gas-to-Energy Plant
HR Green provided design, equipment procurement, construction management support and facility commissioning services for a 3.2 MW power plant for the City of Midland, Michigan. The project consists of a Compressor Building located at the City’s mixed municipal solid waste landfill, and an Engine Generating Plant nearly 3 miles away co-located with the City’s Wastewater Treatment Facility.
Landfill gas is compressed and chilled to drop out moisture prior to conveyance through a 3 mile pipeline to the Engine Generator Building. There, it is combined with digester gas from the wastewater treatment facilities anaerobic digesters. The comingled gas which contains approximately 56% methane is combusted in two Caterpillar 3520 low btu engine generators that produce 1.6 megawatts each. The power is then exported through a switchyard to the local electric utility through a substation and power distribution line adjacent to the facility.
In addition to the electric power generation, HR Green designed a waste heat recovery system. The Heat Recovery System recovers waste heat from the engine’s water jacket and from the engine’s exhaust. The waste heat from the jacket water is piped through a liquid to liquid plate and frame heat exchanger that is in series with a gas to liquid Exhaust Heat Recovery Silencer. The two heat exchangers are located at the Energy Building and are tied into the City’s Wastewater Treatment Facility existing boiler system water heating loop to provide heat to the anaerobic digesters and Wastewater Treatment Facility buildings. Future expansion of the Heat Recovery system includes directing the waste heat to process the wastewater facilities digested sludge into a Class A biosolids product.