APPLICATION OF ALTERING PRESSURE IMPULSES FOR DELIGNIFICATION OF WHEAT STRAW

Abstract

Based on the growth of global energy demand, the limitation of fossil energy sources, and the growth of greenhouse gas emissions due to the use of fuels based on them, there is a need for wider use of renewable energy sources in particular biomass. The main purpose of the stage of pretreatment of lignocellulosic raw materials for hydrolysis in the second-generation fuel ethanol production technology is to destroy the heterogeneous matrix, increase the surface area and porosity of the cellulosic material, and release carbohydrates from the lignin bond, thereby improving enzymatic digestibility. The aim of the study is to compare the effect of alternating impulses of pressure and autoclaving on lignin removal during the pretreatment of wheat straw for enzymatic hydrolysis in the technology of fuel ethanol production. It was determined that increasing the alkali concentration from 0.5 to 4 % wt. reduces the lignin content in the sample from 51.0 to 24.5 % of the initial content for autoclaving at 90 °С, at 121 °С the content of lignin decreases from 40.6 to 17.5 %. Processing at a temperature of 90 °С reduces the lignin content from 43.0 to 18.5 %. The minimum lignin content in the sample was 18.5 % of the initial content for autoclaving at 90 °C for 60 min process, at 121 °С the minimum content of lignin in the sample and the amount of released lignin was observed for 60 min and amounted to 17.5 %. Processing leads to the lignin content in the sample up to 17.5 % for 120 min. The minimum content of lignin in the sample for autoclaving was 17.5 % at 121 °С. For processing, the maximum value of removed lignin was 18.5 % at 90 °С. It was determined that the addition of alternating pressure pulses allows, at atmospheric pressure and a temperature lower than 100 °С, to obtain a degree of lignin removal comparable to the degree of lignin removal in an autoclave at a temperature of 121 °С, which is usually the basis for the process of pretreatment of plant raw materials for hydrolysis in the technology of obtaining fuel ethanol. Bibl. 16, Fig. 5.