A research team led by O Hyon Chol, a section head at the Faculty of Heat Engineering, has established a system of providing electricity for stock farms and fuel for cooking in all seasons by producing methane gas from manure and domestic sewage.
The methane gas production system consists of raw material supply system, a residue discharge system, a system for maintaining the temperature of raw material, an agitation system, a filtration system, a power generation system, a waste heat recovery system, a gas supply system for cooking. All these are placed within a greenhouse by solar heat.
They analyzed the defects revealed during methane gas production at the existing production plants in operation, and conducted a calculation of heat to maintain temperature in winter. On the basis of this, they reinforced the fermentation tank to minimize heat loss and established a system which recovers waste heat from the engine for heating raw material to keep the fermentation temperature at 30℃ to 35℃. It is the waste heat exchanger that recovers waste heat from a methane gas engine. It provides heat necessary for the fermentation tank but has no influence on normal operation of the engine.
Thus, they managed to provide methane gas of 80 to 100m3 in a 100m3 tank, which produced 30~45kWh of power and fuel for cooking every day.
As all the processes in the system such as supply and discharge of raw material, stirring of raw material, cleaning of gas and power generation needs only one person, it is simple in operation and has little operation cost and failure. It is very useful because methane gas can be produced without additional investment as long as there are domestic animals.
The system can satisfy power demands at stock farms and provide heat for cooking without burning any coal. Besides, it can prevent environmental pollution from manure and produce good organic fertilizer to contribute to agricultural production.
© 2021 KumChaek University of Technology