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Study on the Preparation and Applications of Inhibitor for Coal Dust

Author: CaoLiQiong
Tutor: ChengFangQin
School: Shanxi University
Course: Environmental Science
Keywords: Inhibitor of coal dust Wastepaper Waste coke bottle CMC Ethylene glycol
CLC: TD714
Type: Master's thesis
Year: 2011
Downloads: 120
Quote: 0
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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.

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