Combined Heat and Power (CHP) Cogeneration System
The Cogeneration Facility at the BCUA's Little Ferry Water Pollution Control Facility (WPCF) was placed into service during May 2008. Equipment is housed in 2 masonry structures. The system includes required underground utility lines used to transport the biogas to fuel the facility. This combined heating and power facility (CHPH) generates electricity combined with a heat recovery boiler (HRB) to produce hot water. The electricity is used on-site to power the WPCF and the hot water is used to preheat the anaerobic sludge digester process and for building heating during the winter. The CHPF has the capacity to supply 85% of the average electrical demand from the WPCF.
The CHPF contains three (3) Jenbacher 3500 hp each, engines, 1400 kW generator sets and all of the auxiliary heat production equipment in the form of HRBs, carbon filters, radiator, gas blower skid, high voltage electrical distribution and switchgear equipment, controls, and interconnection piping and wiring.
These engines nominally generate 4.2 megawatts (MW) (gross) of electricity of which 4.03 MW are made available for consumption on the BCUA site. Hot water is produced as a by-product of electrical generation and achieved through the use of the engine exhaust HRB and jacket water and lube oil heat recovery using a plate and frame heat exchanger. The hot water is utilized to heat the anaerobic sludge digester process and piped to the interconnection point in the existing hot water process piping. Electrical power distribution to the network is via an underground system. Tie-ins to the electrical systems are located inside BCUA's existing electrical substation.
The engines are capable to run on either biogas at 650 Btu HHV, natural gas at 1030 Btu HHV, or a combination thereof. The biogas is obtained from BCUA's five anaerobic sludge digesters. A blower and filtering skid is installed and located in the ground floor of digester building #2. This skid is provided with two 100% capacity blowers. Each blower is capable of supplying gas for all engines. Gas is pretreated for moisture control with a refrigeration/condensing system and siloxane removal using a carbon filtration system.
The natural gas supply line from PSE&G is provided from the natural gas distribution main located in the roadway in front of the CHPF. There are 2 skids used to compress biogas. One skid has 2 compressors and the second skid has 1 compressor. Each skid is rated to generate 800 SCFM of biogas. Biogas is pretreated for siloxane and H2S removal.
Engine control is provided by the Jenbacher Diane.net control system. This system monitors various engine parameters and makes adjustments as necessary to maintain output to meet energy demand, provide communication for control operation, status, and maintenance of energy infrastructure originating from the CHPF, as well as the required interfaces with the building automation management and life safety systems are also provided.