城市生活垃圾生物干化工艺优化设计研究

发布时间：2018-06-13 03:46

本文选题：城市生活垃圾 + 生物干化　；参考：《武汉理工大学》2015年硕士论文

【摘要】：随着我国经济与社会的快速发展,城市生活垃圾及其引发的环境污染已成为当前城市建设与发展中迫切需要解决的重大问题之一。利用水泥窑特有的高温、长流程与碱性环境特点协同处置城市生活垃圾,不仅处置的无害化环保效果好,而且处置后的残留物可全部成为水泥生产原燃料,是当今世界水泥技术和城市生活垃圾处置技术发展的重要方向。生物干化技术作为水泥窑协同处置城市生活垃圾的核心技术之一,不仅能够去除垃圾中的吸附水和自由水,还能够有效的去除生物结合水,极大的降低垃圾的含水率,提高干化效率和产物RDF(Refuse Derived Fuel,简称RDF)的热值。但是生物干化技术的影响因素较多,工艺不成熟,导致该技术产业化应用过程中出现干化稳定性较差,易生成二次污染物等问题。针对这些问题,本论文以城市生活垃圾为研究对象,研究了初始堆积参数、外加碳源、微生物菌剂对城市生活垃圾生物干化的影响,设计了一套城市生活垃圾生物干化工艺优化方法并研究了这种方法的优化效果。研究结果表明:在生物干化初期,通过调整垃圾堆体的初始堆积参数能够有效改善堆体的气体循环效率和通过速率,进而提高垃圾堆体的温度和微生物活跃程度。研究结果表明,当堆积率为75%、堆积密度为0.51×103kg/m3时,垃圾的温度最高提升到67℃,微生物含量提升到1.25×108cfu/g。与未经过优化堆积参数制备的垃圾干化产物相比,优化后产物RDF的含水率降至33%,热值提高了130%达到12000 kJ/kg。在生物干化初期,通过添加外源菌种能有效解决生物干化前期菌种生长和繁殖速率较低,数量较少的问题。研究结果表明,当外源菌种与渗滤液的体积比为3:1时,获得的微生物菌剂菌种含量最高达到2.4×108cfu/g,对垃圾堆体的水分去除率最大达到49.3%;添加外源菌剂后,堆体干化中期菌种的数量提升46%达到1.5×108cfu/g。干化结束时,与空白组相比,试验产物RDF的含水率降至32.5%,热值提高了105.3%达到11800 kJ/kg。在生物干化中期,通过添加碳源可以解决城市生活垃圾生物干化中后期可分解有机物不足的问题。研究结果表明,木屑更利于微生物分解补充碳源,对城市生活垃圾生物干化后期的促进作用较大;添加木屑后,堆体干化后期温度不降反升,最高达到34℃,而且微生物的活跃程度提高,菌种数量最高达到1.3×108cfu/g。干化结束时,与空白组相比,试验产物RDF的含水率降至34%,热值提高了100.2%达到11500kJ/kg。根据生物干化不同时期的特点,采用不同的优化方法,能够起到优化生物干化工艺,提高垃圾生物干化效率的目的。研究结果表明,采取初期调整堆积参数,添加外源微生物菌剂,中期添加碳源这种协同优化工艺能够显著提升垃圾温度累积效果,累积温度最高可达387.8℃·d;并且高温持续时间较长达到9天;大幅度提升微生物的活跃程度,在干化中期,菌种数量提升56.2%达到1.6×108cfu/g。干化结束时,与空白组相比,RDF含水率降至31%,热值提高了146.1%达到热值提高到12800 kJ/kg,领先于国外RDF热值的平均值。本文研究结果可为城市生活垃圾生物干化技术工艺的优化和应用提供科学依据。
[Abstract]:With the rapid development of China's economy and society, municipal solid waste and its environmental pollution have become one of the most urgent problems to be solved in the construction and development of the city. Moreover, the residue can all become the raw fuel for cement production, and it is an important direction for the development of the world cement technology and municipal solid waste disposal technology. As one of the core technologies of the municipal solid waste disposal, the biological drying technology can not only remove the adsorptive water and free water in the garbage, but also be effective. Removal of biological combined water, greatly reducing the water content of waste, and improving the drying efficiency and the calorific value of the product RDF (Refuse Derived Fuel, RDF). However, there are many factors affecting the biological drying technology, and the technology is not mature, which leads to the problems of poor drying stability and easy generation of two pollutants in the application process of the technology. In this paper, taking urban domestic waste as the research object, the effect of initial accumulation parameters, external carbon source and microbial inoculant on the biological drying of municipal solid waste is studied. A set of optimization methods for the biological drying process of municipal solid waste is designed and the optimization effect of this method is studied. By adjusting the initial accumulation parameters of the garbage dump, the gas cycle efficiency and passing rate can be effectively improved, and then the temperature of the garbage heap and the microbial activity are improved. The results show that when the accumulation rate is 75% and the accumulation density is 0.51 x 103kg/m3, the maximum temperature of the garbage is raised to 67, and the microbial content is raised to the soil. The moisture content of the optimized product RDF decreased to 33%, and the calorific value increased by 130% to 12000 kJ/kg. at the early stage of biological drying. The problem of low growth rate and low number of reproduction in the early stage of biological drying could be effectively solved by adding 1.25 * 108cfu/g. to the waste dry products without optimized accumulation parameters. The results showed that when the volume ratio of the exogenous bacteria and leachate was 3:1, the highest microbial inoculant content reached 2.4 x 108cfu/g and the maximum water removal rate to the garbage dump reached 49.3%. After adding the exogenous bacteria, the number of mid-term strains increased by 46% to the end of 1.5 x 108cfu/g. drying, compared with the blank group. The moisture content of RDF was reduced to 32.5%, and the calorific value increased by 105.3% to 11800 kJ/kg. at the middle of biological drying. By adding carbon source, the problem of decomposable organic matter in the middle and late stages of municipal solid waste could be solved. After the addition of wood chips, the later temperature of the heap drying did not descend, up to 34 degrees, and the activity of microbes increased and the number of bacteria was up to 1.3 x 108cfu/g. drying. Compared with the blank group, the moisture content of the test product RDF decreased to 34%, and the calorific value increased by 100.2% to 11500kJ/kg. according to the biological drying. According to the characteristics of different periods, different optimization methods can be used to optimize the biological drying process and improve the efficiency of dry biomass drying. The results show that the cumulative effect of garbage temperature can be significantly enhanced by the initial adjustment of accumulation parameters, the addition of exogenous microbial agents and the medium of carbon source in the medium term. The highest degree of temperature is up to 387.8. D, and the duration of high temperature is up to 9 days. When the active degree of microorganism is increased, the water content of RDF is reduced to 31%, the calorific value is up to 12800 kJ/kg, and the heat value is up to 12800 kJ/kg compared with that of the blank group at the middle stage of drying, and the heat value is up to 12800 kJ/kg, leading to the foreign RDF heat. The results of this study can provide a scientific basis for the optimization and application of municipal solid waste biological drying technology.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X799.3

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