Study On Utilization Of Corn Stover Enzymatic Hydrolysis Residue

With the growth of the global economy, the contradiction between the growing demand for energy and the scarcity of traditional energy supply increases. Due to the environment concern, bio-ethanol attacts much attention in the world as a green enegey. In China, straw materials, especially the agricuture residues, are one of the richest resourse available for bio-ethanol production. At present, great progress has been obtained in preparation of bio-ethanol from crop stalk. In general, 1.0t bio-ethanol can be obtained from 6.5t corn stalk, and 1t residue is produced in the same time. So far, this residue has not been used effectively. Usually, it is discarded as garbage or burned directly for heat. It not only sabotages the environment, but also wastes resource.In this investigation, corncob and cornstalk residue from enzymatic hydrolysis of producing bio-ethanol was modified and separated by the process of alkaline sulfite pulping (ASP) and the lignosulfonate product obtained in this process was used as concrete plasticizer. The residue which produced in the process of ASP(secondary residue) was used to enzymatic hydrolysis and used to produce fiberboard. The main results were listed as fellows:1). For the corncob residue from enzymatic hydrolysis to produce bio-ethanol, the optimum reaction conditions of ASP were: alkali dosage 14%(Na2O), degree of sulfitation 75~85%, temperature 155℃,time 3~3.5h.Under these conditions, the performance of lignosulfonate was as follows: yield 51.39%, fluidity of cement paste 112mm, surface tension 46.4mN/m, content of sulfonate group 1.89mmol/g.2). For the cornstalk residue from enzymatic hydrolysis to produce bio-ethanol, the optimum reaction conditions of ASP were: alkali dosage 16%(Na2O), degree of sulfitation 85%, temperature 165℃, time 2~3h. Under these conditions, the performance of lignosulfonate was as follows: yield 63.38%, fluidity of cement paste 105mm, surface tension 45.5mN/m, content of sulfonate group 1.75mmol/g.3). The optimum reaction conditions of enzymatic hydrolysis of the secondary residue were: enzyme concentration 40FPU/g, time 48h, temperature 50℃. Under these conditions, the yield of reducing sugar was 69.6%, and the residue in this process was 28.5%4). The fiberboard was made of 20% the secondary residue and 80% pine fiber. The performance of fiberboard was as follows: IB 0.58 MPa, MOR 23.2 MPa, MOE 2871 MPa, TS 8.37%.5). For the cornstalk residue from enzymatic hydrolysis to produce bio-ethanol, after ASP and enzymatic hydrolysis treatments, the finally residue yield was 9.81%. In this residue, ash content was 47.63%, SiO2 content was 42.06%.