Food waste is a kind of available resources of biomass energy.
Kitchen waste, collected from restaurant, school, government offices, works' canteen, hospitals, etc., and fruit&vegetable waste can be mixed together. Big solids eg. bones,chopsticks in mixture are removed through mechanical sorting system; Then by press machine, the separated oil can be recycled as industrial grease eg. bio-diesel, while the sorting of metal occurs before crushing of separated solids, which then are conveyed to be mixed with liquid out of mixture of oil&water, to be fermented in anaerobic reactor for biogas production.
General Flow-chart of biogas plant based on food waste:
1. Sorting of food waste
In addition to a large amount of organic matter, there is also small amount of components in the food waste that can not be biodegradable, such as bones,plastic,glass,stone,metals,shells,wood and silk,etc., should be sorted out to ensure the performances of the follow-up process.
2, Press treatment
Separation of solids and liquid is implemented by press system; The liquid is a mixture of water and oil, the segregation of them is done by centrifugal; The separated oil can be utilized for bio-diesel production, while the separated water would be mixed with solids in the following process.
3, Separation of metal
The water content is 40~50% in the waste after press. The metal in the waste must be removed by technical means,eg. magnetic separation, to avoid physical damage to the subsequent equipment. This also plays the role of resource recovery.
4, Crushing and primary treatment
The waste would be crushed to be in fine dimensions, then to be mixed with separated water from above #2 step, to be processed in pulp condition. The water content of mixture is regulated to be in the range of 10±2%.
5, Anaerobic Digestion
Feedstock is pumped into reactor by progressive cavity pumps. The proper reactor is CSTR(Continuous Stirring Tank Reactor), equipped with agitator and temp. monitoring. It can be all-in-one solution, a combination of biogas production and storage, with gas holder mounted on top of reactor when its single volume is not big.
){kind=link}