【作者】 曹丽琼；

【导师】 程芳琴；

【作者基本信息】 山西大学 ， 环境科学， 2011， 硕士

【摘要】 中国是产煤大国,煤炭在储存和运输过程中由于风力作用引起煤尘飞扬,每年煤尘损失约3000万吨左右,相当于经济损失十几亿元,并且造成严重的环境空气污染。山西省的煤炭产量占全国的四分之一左右,产量位居全国首位,煤尘污染加重了山西的环境问题。在煤炭开采、储运等过程,可引发肺矽病等,给人们的身体健康带来了威胁。现有抑尘技术主要有洒水、挡风抑尘网、遮篷布等物理法抑尘和喷洒具有粘结性和润湿性试剂的化学法抑尘。目前物理抑尘效率低。化学抑尘剂因成本高、可产生二次污染等还基本没有推广应用。现有化学抑尘剂成分主要有粘结性物质羧甲基纤维素(CMC)、聚乙烯醇、聚丙烯酰胺等和润湿性物质乙二醇、十二烷基苯磺酸钠、丙三醇等化学原料。它们大都由棉花、原油等原材料合成,原料成本高、合成工艺要求苛刻,难以工业化实施。本论文试图以废纸和废可乐瓶等废弃物为原料,通过改性或者降解得到常用的煤尘抑制剂原料乙二醇和羧甲基纤维素等,再加工煤尘抑制剂；并对产品的润湿性、粘结性、抗风吹等性能进行了测试和应用试验验证；降低原料成本实现“以废治废”。具体为：(1)以废纸为原料经过碱化、醚化改性制得煤尘抑制剂初级产品羧甲基纤维素。通过实验考察产品的pH和洗涤次数对产品性能的影响。用红外分析生成的产物,并用显微镜观察反应过程中纤维素结构的变化和羧甲基纤维素与煤尘结合的方式。结果表明,PH=7,用85%的乙醇洗涤2次时,产品性能较好。通过对产品进行红外测试,反应生成了CH-O-CH2,证明生成了羧甲基纤维素。通过性能测试,废纸制得的羧甲基纤维素的粘结性能和抗压强度良好；温度在-18℃—50℃时,不影响其使用；保水性良好；加入到煤样后对煤的燃烧热值、硫分无明显影响；取代度大于0.6,满足要求。(2)以废可乐瓶为原料通过破碎、脆化、碱性水解、加酸过滤得到初级产品乙二醇。并测定了不同氢氧化钠质量分数、固液比和反应时间间等情况下废可乐瓶的分解率。通过实验证明：用乙二醇熏蒸脆化后的废旧可乐瓶的分解率大大提高,脆化后比未脆化的样品碱性水解所需的碱的用量大大降低。当氢氧化钠质量分数为5%,固液比为1:8-1:14,反应时间为60min时,废可乐瓶的分解率最高。此时,PET的分解率可达到90%。实现了常压水解废旧可乐瓶。对可乐瓶进行脆化、碱性水解、加酸过滤,可得到比较纯的对苯二甲酸固体和乙二醇溶液。乙二醇溶液作为煤尘抑制剂具有较好的保水性、抗冻性,且不影响煤燃烧的热值。(3)对两种产品进行了喷洒试验、成膜试验等应用试验。结果表明：①乙二醇溶液与CMC溶液相比,前者润湿性和渗透能力好,成膜时间短,后者粘结性好。喷洒后者的煤尘颗粒粒径大于喷洒前者的煤尘颗粒粒径。实际使用中,可以先喷表面活性剂乙二醇,再喷粘结剂CMC,增强抑尘效果。②对于小于15天的短期储煤抑尘,CMC溶液浓度在0.5%-1%之间即可,但是如果储煤时间比较长,CMC溶液的浓度要大于1%。③通过改良配方,在CMC和乙二醇的混合溶液中加入少量聚乙烯醇溶液,可以增强结壳韧性,增强抑尘效果。在气温较低的情况下,可以添加0.5%-1%的硼砂来缩短固化时间。通过储煤场和运输车上的应用试验证明混合抑尘剂效果良好。本论文以廉价的废纸、废旧可乐瓶等为原料得到可作为煤尘抑制剂的物质CMC和乙二醇,提出了废可乐瓶、废纸再利用的新途径,解决的抑尘剂原材料昂贵的问题,实现了以废治污的双重目的。更多还原

【Abstract】 China is one of the largest coal-producing countries. The flying coal dust caused by wind action during the storage and transportation process is about 30 million tons in one year, which will cause the economic loss up to dozen billions yuan. In addition, coal dust can also cause air pollution. The coal production of Shanxi province accounts for about a quarter of the country, ranking first in the country. But Shanxi has suffered more serious environmental cost because of the coal mining. The coal dust during the storage and transportation process, can lead pulmonary diseases such as silicosis, to threat people’s health.Now, dust suppression methods mainly include the chemical and physical methods. The physical methods mainly include the watering, using wind dust network and covering tarpaulin which are all in low efficiency. While the chemical method has achieved very little practical application for the high-cost and the secondary pollution. The main reason of high-cost is that the chemical dust suppressants generally compounded with valuable crude oil, cotton etc. At present, the chemical dust suppressants generally consists of bonding materials such as CMC, PVA, Polyacrylamidede and wetting materials such as Ethylene glycol, SDBS, Glycerol, etc.The paper tried to reduce the cost of raw materials by enlarging the source of raw materials and producting useful material as dust inhibitor with cheap waste resources. Through access to information, waste coke bottles and waste paper are used as raw materials, through the modification or degradation of materials, the CMC and ethylene that commonly used as the raw material of the dust suppressants materials can be got and then they would be reprocessed as the dust inhibitor. And the procucts’performance such as the wettability, the bonding and performance of anti-wind has also been put into the test and applied verification. The results are as follows:(1) CMC was prepared by alkalization and etherficayion reaction in the presence of wastepaper as raw material. Then the influence of the ph value and the wahshing times to the products could be found through the experimental. Also, the structure of the product is analyzed with infrared spectrometer. The changes of the structure of cellulose in reacting and the way of combination of CMC and coal dust is observed with microscope. It has been proved that the performance of the product is best when the PH=7 and wahsed twice by the 85% ethanol. The product is CMC by analysising with Infrared spectrometer. The test has proved that the viscosity and the compressive strength of the CMC get from the waste paper is much better and it can be adapt to a temperature range of -18℃—50℃environment; dust suppressant is still good in water; when it added to the coal samples, increasing the heat of combustion of coal, and have no effect to combustion of coal ash, volatile matter, sulfur; DS>0.6, meet the national standards.(2)With the wast coke bottles as the raw material, through breaking, brittling, alkaline hydrolysis, the primary products of acid ethylene glycol can obtained by filtration. The degradation rate of waste coke bottle under the different sodium hydroxide concentration, solid-liquid ratio and reactin time was also tested. The experiment proved that the degradation rate of the waste coke bottles has improved greatly after fumigation embrittlement. After the embrittlement, the needs of the alkaline in the alkaline hydrolysis will decresde greatly. When the sodium hydroxide concentration is 5%, the solid-liquid ratio is 1:8-1:14 and the reaction time is 60min, the degradation rate of the waste coke bottle is highest. At this time, the PET degradation rate reached 90%. It achieved the hydrolysis of Coke bottles at atmospheric pressure. After embrittlement, alkaline hydrolysis, acid and filter, coke bottles would become relatively pure solid terephthalic acid and ethylene glycol solution. As coal dust Inhibitor, ethylene glycol solution has good water retention, frost resistance, and does not affect the calorific value of coal combustion.(3) The spray test, film test, anti-wind experiment, flammability tests and application tests, etc. have been used to the two products. The experiment has proved that①the wetting and penetration of the ehylene glycol solution is better than that of the Carboxymethyl cellulose solution but less bonding. The diameter of the coal dust sprayed by the carboxymethyl cellulose solution is bigger than that of the coal dust sprayed by the ethylene glycol solution. In practice, the surface active agent ethylene glycol could be sprayed first and the binder could be sprayed later.②As for the dust spression to the short-term storage coal, the concentration of the Carboxymethyl cellulose solution between 0.5%-1% is proper, but if the coal will be stored in a long time, the concentration must beyond 1%.③Through improving the formula, adding little alcohol polyethylene solution into the mixed solution of the carboxymethyl cellulose and ethylene glycol, the crust will become much tough and enhance the effect of dust suppression. Under the environment of the low temprature, the 0.5%-1% borax could be added to shorten the curing time. The experiment of adapting the mixed dust inhibitor in the coal yard and the transport lossies has achieved good results.So the main objective of this work reported that flying coal dust have been prevented by coal dust depressor which was reclaimed from the wast paper and coke bottles as the raw materials. Then the new ways of recycling the waste coke bottles and papers by putted forward and the dual purpose of controling the pollution with the waste materials was achieved. Because of the low cost materials, the cost of the inhibitor decressed greatly and the experiments has proved its effect.更多还原