碱预处理对埃塞俄比亚画眉草厌氧消化产气性能的影响

发布时间：2018-04-09 22:32

本文选题：画眉草　切入点：厌氧消化　出处：《北京化工大学》2015年博士论文

【摘要】：厌氧消化技术可将生物质废弃物转化为可再生的生物能源。每年在世界不同地区会生产大量的农业废弃物。在非洲,画眉草是主要生产粮食作物,美国和一些欧洲国家也都有大量的画眉草产生。画眉草已成为一种新的木质纤维素生物质的潜在来源,可通过厌氧消化技术转化为生物甲烷。然而,画眉草中大量木质纤维素化合物使微生物的水解受到限制,从而降低了生物甲烷的厌氧消化速度。在厌氧消化过程之前,对木质纤维素生物质的进行预处理,可以提高秸秆类生物质的水解速率和生物甲烷的转化率。在本研究中,采用NaOH和KOH对画眉草秸秆进行预处理,以破坏画眉草的纤维结构,促进厌氧消化的转化速率。本研究的目的包括：(1) NaOH预处理后画眉草的生物甲烷潜力分析；(2)对画眉草的NaOH预处理条件进行探讨,主要包括：预处理时间,NaOH浓度和固体浓度；(3)研究不同浓度KOH预处理条件下,不同有机负荷时画眉草的厌氧消化性能；(4)分析了碱预处理前后画眉草的主要成分和结构的变化；(5)分析在厌氧消化的末端,厌氧消化出料的肥料价值。确定了NaOH预处理后画眉草的沼气产量和甲烷产量(NaOH浓度分别为1%,2%,4%和6%,有机负荷为50 g/L,65g/L,80g/L和95 g/L)。结果表明,在有机负荷为80g/L时,采用4%的NaOH预处理,累积产气量和生物甲烷产量比未处理画眉草秸秆分别高出40.1%和48.2%。变化主要化学组成和物理微结构的分析结果表明,有4.2-22.3%三天后预处理用NaOH总木质纤维素组合物的去除。因此,氢氧化钠预处理画眉草稻草后,可以提高沼气产量和生物甲烷量,同时与未经处理的样品相比,提高了生物降解能力。采用KOH预处理画眉草的时间为4天,结果表明,在有机负荷为65g/L时,采用2%的KOH进行预处理式,与未处理相比,沼气产量和甲烷产量分别提高了51.4%和68.8%。未预处理的画眉草TS、VS去除率分别为52.4-62.3和50.4-61.4%,预处理后的TS、VS去除率达到59.9-70.7和61.6-72.2%。这主要是由于经过氢氧化钾的预处理后,画眉草的纤维素,半纤维素和木质素受到破坏,已经通过傅里叶变换红外光谱(FTIR)对画眉草预处理前后的内部结构和组成的变化进行了分析。这些结果证实,KOH预处理技术可以破坏画眉草的内部纤维结构,显著改善画眉草的生物甲烷产量,提高画眉草的可生物降解性。
[Abstract]:Anaerobic digestion technology can convert biomass waste into renewable bioenergy.Large quantities of agricultural waste are produced in different parts of the world every year.In Africa, thrush grass is the main food crop, the United States and some European countries have a large number of thrush grass.Trifolium vulgaris has become a new potential source of lignocellulosic biomass, which can be converted to biomethane by anaerobic digestion.However, a large number of lignocellulosic compounds in Thrushcross have limited microbial hydrolysis, thus reducing the anaerobic digestion rate of biomethane.Pretreatment of lignocellulosic biomass before anaerobic digestion can improve the hydrolysis rate of straw biomass and the conversion of methane.In this study, NaOH and KOH were used to pretreat the straw in order to destroy the fiber structure and promote the transformation rate of anaerobic digestion.The purpose of this study was to analyze the potential of biomethane after pretreatment with NaOH. (2) to study the pretreatment conditions of NaOH, including: pretreatment time, concentration of NaOH and concentration of solid, etc. (3) the pretreatment conditions of different concentrations of KOH were studied.Under different organic loading, the anaerobic digestibility of Thrushcross was analyzed. (5) the fertilizer value of the anaerobic digested material was analyzed at the end of anaerobic digestion by analyzing the changes of the main composition and structure before and after alkali pretreatment.The concentration of methane and methane after NaOH pretreatment was determined to be 1% and 2%, respectively, and the organic load was 50 g / L ~ 65 g / L ~ (80) g / L and 95 g / L ~ (-1) 路L ~ (-1) ~ (-1).The results showed that when the organic load was 80g/L, the cumulative gas production and the biomass methane yield were 40.1% and 48.2% higher than those of untreated straw respectively with 4% NaOH pretreatment.The analysis of the main chemical composition and physical microstructure showed that there were 4.2-22.3% NaOH total lignocellulose compositions removed after 3 days pretreatment.Therefore, pretreatment with sodium hydroxide can increase biogas production and biomethane production, and increase biodegradability compared with untreated samples.The time of pretreatment with KOH was 4 days. The results showed that the biogas production and methane yield increased by 51.4% and 68.8% respectively when the organic load was 65g/L and 2% KOH was used as pretreatment formula.The removal rates of TSV S were 52.4-62.3 and 50.4-61.4, respectively. After pretreatment, the removal rates of TSV S were 59.9-70.7 and 61.6-72.2, respectively.This is mainly due to the destruction of cellulose, hemicellulose and lignin of Thrushcross grass after pretreatment with potassium hydroxide.Fourier transform infrared spectroscopy (FTIR) has been used to analyze the changes of internal structure and composition before and after pretreatment.These results showed that Koh pretreatment technology could destroy the internal fiber structure, improve the biomass methane production, and enhance the biodegradability of Thrushcross.
【学位授予单位】：北京化工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X712;S216.4

【相似文献】