Research On Large Biogas Plant Associated Ground Source Heat Pump Heating System In Cold Area

In northeast cold regions,because of the low air temperature and the low ground temperature in winter,without warming to the biogas fermentation rector,there are many problems about industrial production of biogas.For example the rates of producing and fermentation temperature are low.Whether the biogas industrial production can spread in cold regions depends how to solve the continuous production of biogas and reduce the heat lose loading.It presents a new thought about using ground-source heat pump and boiler to warm the biogas fermentation system in accordance with these problems in the paper.The water in the circulatory system is warmed by the ground-source heat pump and boiler,and the fermentation solution is warmed by the hot water via steel pipe heat exchanger in the biogas fermentation rector.Then the solution temperature maintains at above 20?,and the biogas is fermented all the year.The difficult of no biogas in winter is solved in the cold region.First of all,physical properties of fermentation solution are measured systematically.For example,density,viscosity,heat capacity and thermal conductivity.With the determination of physical properties,it makes the foundation of research on heat transfer,design of warming system,calculation of fermentation reactor heat lose and building the model of fermentation reactor heat lose.Secondly,In this dissertation,it describes how to design the warming-up system of the biogas plant.Including heat loading of feeding fermentation solution,heat lose loading of fermentation reactor,heat lose loading of pipe,heating load of heat source.With the calculation of heat loading,the heat source and cycle pump are chose correctly.At last,it forms a set of warming-up system which is suitable for the 700m3 anaerobic fermentation reactor.And then,a monitoring system which is based on force control is set up to monitor the warming-up system of biogas plant in Lan ling,Jixi.The monitoring system can collect the operating date at any moment.After the analysis of the collected date,the heat lose load of fermentation reactor and the heating load of heat source are come into conclusion.The low of fermentation temperature change with air temperature and the minimums gas production that guarantee the positive energy output are summed up.At last,the heat lose model of fermentation reactor is established.The monitoring date during heating period is analyzed systematically using Degree-day method,which verified the feasibility of the heat lose model.It can forecast the whole heat lose of fermentation reactor with the heat lose model,which can provide reference for the design and calculations of large biogas plant in the future.