Effect of chopping straw on the intensity of biogas output

Abstract

Straw has a high energy capacity, but it is not ideal for the operation of biogas plants, since it contains a large amount of nitrogen-free substances, and only 4-6% nitrogen and mineral salts, but if it is properly pretreated, it is possible to reduce the fermentation time and increase the biogas yield. The positive results of pretreatment of biological raw materials are a high degree of grinding and homogenization of raw materials; reduction of the biomass fermentation period; the release of natural enzymes that are biological catalysts for the fermentation of biomass; stabilization of biological processes, which leads to the absence of foam and floating crust in the upper part of the bioreactor; the percentage of methane in biogas increases to 70-75 %. The aim of the study is to determine the intensity of methane fermentation of crushed buckwheat, rapeseed, soybean straw and corn stalks, depending on the size of crushed particles and the method of grinding. The article discusses the issue of determining the dynamics of biogas output depending on the method and geometric dimensions of grinding buckwheat straw, soybeans, rapeseed and corn chaff in a mesophilic mode of fermentation. The following devices were used to prepare the straw: shears, hammer mill, feed chopper and extruder. Additionally, soaking was carried out in water at a certain temperature. The prepared biomass together with the seed in a ratio of 1: 4 was put into laboratory fermenter bags and a thermostat. The biogas yield was measured for 42 days using special methods, which are patented in Ukraine. Based on the measurement results, graphs were built that characterize the dynamics of biogas output.

Retraction Note: Prospects of improving biogas technologies by increasing productivity of the methane generation process due to complex processing of organic waste

“…In [30] it is noted that, despite its high energy capacity, straw as a raw material is not ideal for the operation of biogas plants, since it contains a large amount of non-nitrogenous substances, in particular 33-35 % of cellulose, 21-22 % of hemicellulose, 18-22% of lignin, 3-5 % of proteins and only 4-6 % of nitrogen and mineral salts, but if it is prepared in advance, it is possible to reduce fermentation time and increase the production of biogas. The authors suggest grinding the raw substrate (buckwheat, rapeseed, soybean straw and corn stalks) to increase the intensity of methane fermentation.…”