To reclaim and utilize biogas produced during sludge treatment process in sewage treatment plants

the schemes and flow processes for utilizing the biogas were studied.A direct-fired heat pump heating system based on biogas from sewage treatment plant was structured

and the configuration and economic analysis of the system were also made.Results indicated that compared with coal-fired boiler

gas-fired boiler and electricity driven heat pump

a biogas direct-fired heat pump system of 600 kW input power

which was assumed to operate in heating mode for 300 days annually

could save 510 t of standard coal or 3.25?105 m3 of natural gas or 7.72?105 kW穐 of electricity.The initial cost of the system could be paid back in no more than 2.6 years.Therefore

this heating system was featured by good economic

energy saving and emission reduction properties

and the economic and environmental interests produced by the system should be significant.