【作者】 郭欧燕；

【导师】 杨改河；

【作者基本信息】 西北农林科技大学 ， 生态学， 2009， 硕士

【摘要】 我国农村人口众多、能源短缺,大力发展沼气技术,既为人们提供了生物质能源,又利用了农业(这里指大农业,包括畜牧业)废弃物,同时还为农户提供了有机肥料,具有显著的能源、经济、生态和环保效益,在农作物和人畜粪便等废弃物的无害化处理及资源化利用中已得到广泛应用。厌氧发酵是指各种有机物在厌氧条件下被各类发酵微生物分解转化,最终生成沼气的过程。由于厌氧消化过程受原料的组成、环境条件和大量的细菌、真菌等因素的调控,其反应机理非常复杂。其中,温度是影响厌氧消化的主要因素之一。温度的适宜与否直接决定了厌氧消化的成败。目前为止,温度对厌氧消化产气量和对原料发酵时间长短的影响没有确定的数据和记录。理论上,10～60℃的范围内,沼气均能正常发酵产气。在实际操作中,很多地区根据理论值指导生产,却没有收到显著的成效,结果造成人力、物力和财力的浪费。因此,研究和探索厌氧消化过程中,不同发酵温度对厌氧消化产气量、产气速率的变化规律,并寻求最优的发酵温度很有必要。本研究旨为实现沼气发酵的可控化及我国沼气发酵适宜区的评价提供科学依据,同时也为解决农业废弃物不合理利用而造成的环境污染问题和农业环境污染源头治理对策制定提供理论依据和技术支撑。本试验通过自行研究设计的可控性恒温发酵装置,以鸡粪分别与水稻秸秆、小麦秸秆和玉米秸秆干物质量比分别为1:1、2:1和3:1的混合原料为发酵原料,以常温厌氧发酵池的底物为接种物,在总固体TS(Total Solid)质量分数为8%的条件下进行批量试验。研究了它们在11个恒定发酵温度10℃、15℃、20℃、25℃、30℃、35℃、40℃、45℃、50℃、55℃和60℃下的产气情况,并用SAS软件对试验结果进行多元回归方程,建立最优回归方程,得出不同发酵原料的最优发酵温度、相应的消化时间和最大干物质累积产气量。得出以下主要结论:(1)本试验所用的混合原料在11个恒定温度组下均能正常产气,但在10℃和15℃的温度下,混合原料需要经过一段停滞时期才能正常产气,且产气速率变化不大,没有出现明显的产气高峰期。其它温度组里,鸡粪:稻秆1:1、鸡粪:稻秆2:1、鸡粪:稻秆3:1、鸡粪:麦秆1:1、鸡粪:麦秆2:1、鸡粪:麦秆3:1、鸡粪:玉米秆1:1、鸡粪:玉米秆2:1和鸡粪:玉米秆3:1分别在7～43d、7～42d、13～41d、7～39d、11～39d、10～41d、5～43d、9～43d和6～40d左右达到产气高峰,并分别在厌氧发酵后的31～45d、35～46d、30～46d、34～48d、36～46d、36～45d、35～46d、35～46d和35～46d左右,累积产气量达到总累积产气量的90%,表明发酵完成。(2)由相关性分析结果得出,本试验所用的混合原料的发酵温度与最大产气速率均呈正相关,即厌氧发酵最大产气速率在10～60℃范围内,基本上随着温度的升高而升高;与累积产气量均呈正相关,即在10～60℃范围内随着温度的升高,反应进行的越彻底。发酵温度与到达最大产气速率的时间和厌氧发酵时间均呈负相关,即在10～60℃范围内,厌氧发酵最大产气速率的最大峰值出现时间和厌氧发酵时间,基本上均随着温度的升高而缩短。(3)用SAS软件对试验数据进行多元回归分析得出:鸡粪:稻秆1:1的最佳温度为48℃,最佳发酵时间为53d,对应的最大干物质累积产气量为299.54mL/g;鸡粪:稻秆2:1的最佳温度为52℃,最佳发酵时间为50d,对应的最大干物质累积产气量为296.02mL/g;鸡粪:稻秆3:1的最佳温度为42℃,最佳发酵时间为50d,对应的最大干物质累积产气量为295.70mL/g;鸡粪:麦秆1:1的最佳温度为53℃,最佳发酵时间为47d,对应的最大干物质累积产气量为271.78mL/g;鸡粪:麦秆2:1的最佳温度为47℃,最佳发酵时间为47d,对应的最大干物质累积产气量为265.80mL/g;鸡粪:麦秆3:1的最佳温度为50℃,最佳发酵时间为56d,对应的最大干物质累积产气量为306.59mL/g;鸡粪:玉米秆1:1的最佳温度为57℃,最佳发酵时间为45d,对应的最大干物质累积产气量为274.66mL/g;鸡粪:玉米秆2:1的最佳温度为48℃,最佳发酵时间为49d,对应的最大干物质累积产气量为296.18mL/g;鸡粪:玉米秆3:1的最佳温度为48℃,最佳发酵时间为53d,对应的最大干物质累积产气量为299.54mL/g。更多还原

【Abstract】 There are large population and energy shortage in the rural areas of China, promoting the innovation development of biogas technology can not only provide a source of biomass energy, but also make use of the agriculture and livestock waste, as well as provide organic fertilizer for farmers, so biogas technology has significant energy, economic, ecological and environmental benefits, and has been applied abroad on the innocuity dealing with castoff and resource utilization, for example, crop straw, the dejecta of human or livestock and so on. Anaerobic fermentation is the process that various types of organic waste are decomposed to generate biogas by microbial in anaerobic conditions. It is used in waste treating of animals and vegetable,widely.Anaerobic digestion processing is influenced by bacteria, protozoan and epiphyte etc. Its reactive mechanism is complex. Temperature is one of the main factors. Whether the temperature is proper that decided the success or fail of the anaerobic digestion directly. Up to now, temperature was the only one which had no assured data and record on the influence of producing biogas capacity through anaerobic digestion and the material fermented time. Firedamp could fermented and produced gas at the 10～60℃in theory. A lot of region coached base on the theory value in practice operation, but received little effect, and wasted the manpower, material resources and financial. The study is to explore on the rule that the influence of ferment temperature to the producing gas capacity through anaerobic digestion and biogas producing speed in the process of anaerobic digestion, seeking optimal ferment temperature, the purpose of realizing the controlling the firedamp ferment and providing the scientific according as estimate in order region of China, offering theory and technology support on settling the problem of environments pollution in the using inconsequence the agriculture castoff and the father countermeasure on the headstream of the agriculture pollution.This experiment carried through batch test using ferment equipment of constant temperature could be controlling and designed by ourselves, the proportioning materials of TS ratio (1:1, 2:1, 3:1) of chicken feces respectively with rice straw, wheat straw and corn straw as raw materials, and the fundus-thing of normal temperature oxygen-detested digesting pool served as the inoculate substance, with the condition of the total solid mass fraction is 8%. Chose 10℃, 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃and 60℃as constant temperature. Through research, and analyzed the method of excessive factor regress by SAS software, and the best excellent regress equation was found, the most proper ferment temperature of different ferment material was educed and the correspond digest time and the most tolerance produced by the substance cumulate were found at the same time.The main conclusions were drawn as following:1. The mixed materials can producted biogas under 11 constant temperature group normally. But mixed materials need to be after a period of stagnation at 10℃and 15℃, and the biogas production rate change not change significantly. 1:1 mixture of chicken feces and rice straw, 2:1 mixture of chicken feces and rice straw, 3:1 mixture of chicken feces and rice straw, 1:1 mixture of chicken feces and wheat straw, 2:1 mixture of chicken feces and wheat straw, 3:1 mixture of chicken feces and wheat straw, 1:1 mixture of chicken feces and corn straw, 2:1 mixture of chicken feces and corn straw and 3:1 mixture of chicken feces and corn straw reached the max biogas production in 7～43d, 7～42d, 13～41d, 7～39d, 11～39d, 10～41d, 5～43d, 9～43d and 6～40d., and percentage the cumulative biogas production above 90% in 31～45d, 35～46d, 30～46d, 34～48d, 36～46d, 36～45d, 35～46d, 35～46d and 35～46d. The fermentation completied.2. By the results of correlation analysis, the fermentation temperature of the mixture materials positively correlated the maximum biogas production rate, and also correlated the cumulative biogas production. It means that the maximum daily biogas production and cumulative biogas production increased as the temperature increased. The the fermentation temperature of the mixture materials negatively correlated the day of max biogas production and aerobic digestion time. It means that the higher of temperature, the earlier of the day attained maximum daily biogas production appeared, and the overall length of the fermentation period was shortened as temperature increased within a certain range.3. The experimentation results were analyzed with the method of excessive factor regress by SAS software. The corresponding biogas production per unit dry matter of 1:1 mixture of chicken feces and rice straw which ferment at 48℃for 53d was 299.54mL/g. The corresponding biogas production per unit dry matter of 2:1 mixture of chicken feces and rice straw which ferment at 52℃for 52d was 296.02mL/g. The corresponding biogas production per unit dry matter of 3:1 mixture of chicken feces and rice straw which ferment at 42℃for 50d was 295.70mL/g. The corresponding biogas production per unit dry matter of 1:1 mixture of chicken feces and wheat straw which ferment at 53℃for 47d was 271.78mL/g. The corresponding biogas production per unit dry matter of 2:1 mixture of chicken feces and wheat straw which ferment at 47℃for 47d was 265.80mL/g. The corresponding biogas production per unit dry matter of 3:1 mixture of chicken feces and wheat straw which ferment at 50℃for 56d was 306.59mL/g. The corresponding biogas production per unit dry matter of 1:1 mixture of chicken feces and corn straw which ferment at 57℃for 45d was 274.66mL/g. The corresponding biogas production per unit dry matter of 2:1 mixture of chicken feces and corn straw which ferment at 48℃for 49d was 296.18mL/g. The corresponding biogas production per unit dry matter of 3:1 mixture of chicken feces and corn straw which ferment at 48℃for 53d was 299.54mL/g.更多还原