稻秸甲烷乙醇联合发酵技术研究

发布时间：2018-06-20 10:17

本文选题：稻秸 + 酸碱预处理　；参考：《华中农业大学》2016年博士论文

【摘要】：由于秸秆沼气工程的沼渣中仍残留较高的纤维和有机物含量,对这部分残余有机碳进行回收利用,可大幅度提高原料利用率和能量转化效率。针对目前较为成熟的厌氧发酵技术和纤维乙醇技术,利用稻秸进行沼气和乙醇联产以解决厌氧发酵工程中大量沼渣难以利用问题,及纤维乙醇过程中的原料成本问题,在联产生物能源的同时,可实现生物质全效降解。以酸碱浓度、温度和时间为主要考察因素,研究了酸碱预处理条件对稻秸的降解和糖化产率的影响。结果表明碱浓度和温度越高,半纤维素和木质素去除率越高,半纤维素和木质素的最高去除率分别为89.45%和88.92%;而酸预处理主要针对稻秸中的半纤维素,最高的半纤维素降解率为75.58%。从葡萄糖产率和有机物浓度来看,碱预处理的葡萄糖产率和有机物浓度明显高于酸预处理,最优的水解条件为2%浓度的NaOH,60℃和60h,在此条件下,葡萄糖产率为55.5%。另外,对于臭氧和氨水联合预处理,随着臭氧用量的增加,葡萄糖浓度先增加后降低,0.75g/g臭氧用量时葡萄糖浓度和还原糖浓度最高;与未处理组相比,氨水预处理4h的还原糖浓度提高了82.06%,而氨水预处理6h和8h的还原糖浓度无明显提高,故适宜的臭氧氨水联合预处理参数为臭氧用量0.75g/g和氨水预处理时间6h。采用厌氧消化和乙醇发酵联合技术降解稻秸,提高生物能源产率,通过比较直接厌氧发酵、“乙醇甲烷”联产、乙醇甲烷连续发酵和“甲烷乙醇”联产四种工艺的沼气产量、甲烷产量和乙醇产量,并根据木质纤维素和单糖组成研究各工艺的木质纤维素降解过程,结果表明乙醇甲烷联合发酵模式具有一定优势,乙醇甲烷联产和连续发酵的能量输出比直接厌氧发酵分别提高17.12%和49.36%。基于对沼渣生产乙醇技术的探索,选择了甲烷乙醇联合发酵模式,研究酸碱和臭氧氨水预处理对沼渣酶解糖化效率的影响,优化甲烷乙醇联产工艺中的厌氧发酵条件和预处理参数。采用酸碱预处理对甲烷乙醇联产工艺中厌氧消化条件及纤维乙醇转化的预处理参数进行了研究,结果表明中温低浓度的厌氧消化对稻秸纤维素结果破坏明显,而且预处理过程纤维素损失较低,葡萄糖得率较高,所以中温低浓度获得的厌氧消化纤维产乙醇效果较好;酸碱预处理条件的对比表明在温和温度条件下碱预处理对厌氧消化纤维产乙醇更具优势。适宜的碱预处理条件为60℃,3%浓度NaOH和6h,纤维素回收率高达80%以上,葡萄糖得率较高,为58.66%;中温低浓度的厌氧消化纤维的乙醇产量达87g/kg,有效地提高了厌氧消化纤维产乙醇的效率。在甲烷乙醇联产工艺中,臭氧和氨水联合预处理可有效利用沼渣中有机碳,臭氧和氨水联合预处理对高温厌氧消化后的沼渣的水解糖化效率较高。甲烷乙醇联产工艺质量能量平衡分析表明采用55℃和17%发酵浓度厌氧发酵24天的沼渣进行生产乙醇,具有最高的净能量产出,为6416kJ,在此条件下每千克稻秸的甲烷产量和乙醇产量分别为142.8g和65.2g,证明了厌氧消化联合乙醇发酵生产甲烷和乙醇是一种有效的生物炼制过程,可实现有机碳的联合和连续利用。
[Abstract]:Due to the still high content of fiber and organic matter remaining in the biogas residue of straw biogas engineering, the recovery and utilization of this part of residual organic carbon can greatly improve the utilization rate of raw materials and energy conversion efficiency. A large amount of biogas residue in oxygen fermentation engineering is difficult to use, and the cost of raw materials in the process of fiber ethanol. The total biodegradation of biomass can be realized while the biological energy is produced. The effects of acid base concentration, temperature and time on the degradation and saccharification yield of rice straw are studied. The higher the concentration and temperature, the higher the removal rate of hemicellulose and lignin, the highest removal rate of hemicellulose and lignin was 89.45% and 88.92%, while the acid pretreatment mainly aimed at the hemicellulose in the rice straw, and the highest hemicellulose degradation rate was 75.58%. from the glucose yield and the concentration of the machine. The concentration of organic matter is obviously higher than that of acid pretreatment. The optimum hydrolysis condition is 2% concentration of NaOH, 60 C and 60H. Under this condition, the yield of glucose is 55.5%.. With the combination of ozone and ammonia water, the glucose concentration increases first and then decreases with the increase of ozone dosage. The glucose concentration and reducing sugar concentration are the highest when the amount of 0.75g/g ozone is used. Compared with the untreated group, the reducing sugar concentration of the ammonia pretreatment 4H increased by 82.06%, while the reducing sugar concentration of the ammonia water pretreatment 6h and 8h was not obviously improved. Therefore, the optimum parameters of the combined pretreatment of ozone and ammonia water were the combination of anaerobic digestion and ethanol fermentation by the combined technology of anaerobic digestion and ethanol fermentation to improve the biodegradation of the rice. The production of methane, methane production, methane production and methane ethanol production, methane production and ethanol production were compared by comparing direct anaerobic fermentation, methane ethanol production, methane ethanol production and ethanol production in four processes. The degradation process of lignocellulose and monosaccharide composition was studied on the basis of lignocellulose and monosaccharide composition. The results showed that the combined fermentation of methane ethanol was combined with methane fermentation. The model has some advantages. The energy output of ethanol methane co production and continuous fermentation is increased by 17.12% and 49.36%., respectively, based on the exploration of ethanol production by biogas residue. The combined fermentation mode of methane ethanol is selected to study the effect of acid base and ozone ammonia water pretreatment on the enzymatic hydrolysis of Biogas residue and optimize the methane ethanol combination. Anaerobic digestion conditions and pretreatment parameters of cellulose ethanol conversion in the process of methane ethanol production were studied by acid base pretreatment. The results showed that low medium temperature and low concentration of anaerobic digestion showed obvious damage to the results of rice straw cellulose, and the loss of cellulose was lower in the pretreatment process. The yield of glucose was higher, so the effect of anaerobic digestion fiber obtained by medium temperature and low concentration was better, and the comparison of acid base pretreatment conditions showed that under mild temperature conditions, alkali pretreatment was more advantageous to anaerobic digestion fiber. The suitable alkali pretreatment conditions were 60 degrees C, 3% concentration NaOH and 6H, and cellulose recovery rate up to 80%, Portuguese. The yield of glucose is 58.66%, the yield of ethanol in anaerobic digestion fiber with low medium temperature and low concentration is 87g/kg, which can effectively improve the efficiency of ethanol production by anaerobic digestion fiber. In the process of methane ethanol production, the combined pretreatment of ozone and ammonia water can effectively use organic carbon in the biogas sludge and the combined pretreatment of anaerobic and ammonia water to the anaerobic digestion of high temperature. The efficiency of hydrolysis and saccharification of biogas residue is high. The analysis of quality and energy balance of the process of methane ethanol production shows that the methane production with the highest net energy output, which is 6416kJ, is 6416kJ. The methane yield and the ethanol yield per kilogram of rice straw are 142.8g and 65.2g respectively. The production of methane and ethanol by oxygen digestion combined with ethanol fermentation is an effective biorefinery process, which can achieve the combined and continuous utilization of organic carbon.
【学位授予单位】：华中农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S216

【参考文献】