For co-digestion and co-gasification or waste treatment processes
Crude glycerol can also be used as raw material for co-digestion in anaerobic digestion tank to improve biogas production. ROBRA added 6% glycerol to biogas degrading tank, which could increase methane yield by about 80%. Crude glycerol can also be used as a co-matrix of industrial waste to increase the production of hydrogen and methane during waste treatment. The feasibility of syngas production by co-gasification of crude glycerol and hardwood chips was investigated by WEI. The reaction was carried out in a pilot scale fixed-bed suction gasifier. The main components of syngas were CO, CO 2, H2, CH4 and N2. The reactor could better complete the co-gasification of crude glycerol and hardwood chips and was stable.FOUNTOULAKIS investigated the effect of crude glycerol on the performance of municipal solid waste treatment in an anaerobic reactor. Without crude glycerol, the daily production of methane was 1400 mL. After adding crude glycerol, the production of methane could reach 2094 mL. At the same time, the addition of crude glycerol in the feed would also increase the production of hydrogen. BODIK studied the denitrification process of municipal wastewater treatment plant using biodiesel by-product as organic carbon source. The experiment was initially carried out in the laboratory, and was extended to the wastewater treatment plant after obtaining good results. It was found that the denitrification efficiency of the process could be increased. The application of crude glycerol in co-digestion or waste treatment process is the simplest and extensive treatment of crude glycerol. The added value of the product is not high, and its utilization value is not high. It is not a long-term road for crude glycerol application.
Used as animal feed
Crude glycerol, a byproduct of biodiesel, can be directly used as animal feed after simple treatment. DonKIN studied the feasibility of replacing part of corn with crude glycerol as feed for dairy cows. It was found that 15% crude glycerol had no effect on milk yield and composition, and alleviated the shortage of corn. Using crude glycerol, a byproduct of biodiesel, as animal feed is also economical. Reducing the cost of animal feed may also reduce the price of meat. At the same time, it can provide an additional source of product income for biodiesel refineries. But it is also a kind of crude glycerol treatment method with low added value. At the same time, it is necessary to consider whether the residual metal catalyst in crude glycerol will do harm to animal health and food safety.
