Environmental assessment of sawdust blends with glycerol burning

Abstract

Biodiesel production is limited by the development of the relatively high cost of the product. To reduce the cost it is reasonable to maximize the use of rape methyl ester (RME) production by-products – cake and glycerol fraction. Rapeseed cake is widely used for animal feed, this cake economically is best to use as a vitamin and protein additive product for cattle, pigs and poultry. In production of 1000 kg of RME about 101 kg of green glycerol is obtained, in which there is 87-92 % of pure glycerol. At the low RME output the most economical way of glycerol use is to use it as an additive for fuel briquettes production. In the experimental basis of the Aleksandras Stulginskis University, Institute of Agricultural Engineering the investigations in the sawdust and green glycerol mixture combustion process and environmental assessment are carried out. The tests showed that the calorific value of glycerol was 22-23 MJ·kg-1, also it is suitable as a binder by pressing sawdust briquette production. There were investigated wood sawdust mixes with 30, 50 and 80 % glycerol. It was determined that after insertion of 80 % green glycerol in wood sawdust mixture of 8 % moisture content, the calorific value increased from 16.28 MJ·kg-1 to 23.7 MJ·kg-1. As well as experimentally the mixture combustion temperature dependence on the supplied air was determined. The investigations in wood chip and glycerol mixture combustion showed that the NOx content in the smoke did not exceed the permissible limit of 650 mg·m-3, SO2 content in the smoke was found only as the traces and the ash content increases slightly with increasing of the glycerol content in the mixture.