Oxidation Behaviours Of Low Rank Coal By H₂O₂

The coal resources of Xinjiang province are abundant and centralized.According to exploration and prediction,the total amount of coal resources is about 2.19 trillion tons,about 40.6% of the national total.Coal resources are better on overall,mainly in long flame coal,noncaking coal and weakly caking coal and low rank coal.Currently,low rank coal is mainly used for power generation,gasification,semi-coke production and some coal chemical industry.Therefore,we should process and utilize the low rank coal on local,and produce the high valueadded,easy storage and transportation of the products,which has a very good market prospects and development space.With the Ha Mi lignite and Shihezi bituminous coal from Xinjiang as the research object,this paper investigated the oxidation reaction between coal and H₂O₂,and extract the products of the water-soluble and the alkali soluble.In order to improve the efficiency and effectiveness of the oxidation,we added Fe²⁺ to the oxidation system to form Fenton reagents and generate ?OH free radicals for enhancing oxidation.We investigated the key factors on the oxidation process like the amount of H₂O₂ and catalysts,reaction time,reaction temperature,pH value.We researched the most optimization conditions of reaction to increase products yield and reduce the loss of organic matter in the coal by analyzing the water-soluble yield,the alkali-soluble yield,residue rate and volume of gas.Meanwhile,the CS2/NMP extract and residue of Shihezi bituminous coal were oxidized at 40?,60? and 80? to explore the oxidation process of coal and H₂O₂.By the yield under various conditions,the results are as follows:?1?In direct oxidation process between Ha Mi lignite and H₂O₂,with the amount of the oxidizer increased,the oxidation of coal residue reduced and the oxidation products decreased also.The water-soluble yield reached a maximum 15.12% in the ratio of 1/15 of coal to 30% H₂O₂ and then rapid decrease.The higher the reaction temperature,the more vigorous of oxidation reaction.And at 80 ?,the residue yield was only 2.50% and volume of gas was 1369 m L/g coal.With the oxidation time increasing,the products were gradually oxidized.The watersoluble increased initially and then decreased,and reaching 18.19% at 24 h.?2?The catalyst of Fe²⁺ was introduced at the oxidation reaction of Ha Mi lignite to H₂O₂.With the reaction temperature increased,the oxidation products increased and the decomposition of oxidation increased also.The highest yield of water-soluble was 27.73% at 80?,and the alkali-soluble was 9.25% at 40?.With the value of pH increased,the yield of products presented a trend of increasing initially and then decreasing.In the value pH of 4.5,the water-soluble and the alkali-soluble reached a maximum 28.33% and 13.13%,respectively.With the amount of catalyst increased,the water-soluble and the alkali yield showed a trend of reducing first and then increasing.At the ratio of 1/10,there were a maximum yield 25.70% and 19.14%,respectively.With reaction time extended and the reaction processing,oxidation residue and the water-soluble reduced.And the water-soluble yield was 28.48% at 3h;the alkali increased first and then decreased,and yield was 23.04% at 9h.?3?When the reagent ratio was low at the oxidation reaction of Shi Hezi bituminous coal and Fenton reagents,the water-soluble yield did not change significantly,and increases initially and then decreases with the reaction temperature increased.The maximum yield of the watersoluble was 46.32% and the lowest yield of residue was 88.60% at a ratio of 1/10.The maximum yield of the water-soluble at a value pH of 1.5;the lowest yield of residue was 84.17% at a value pH of 3.The water-soluble yield did not increase with the reaction time extended.There was a maximum yield 45.53% and then declined at 2h.Compared to coal,the extracts and residue have a higher reactivity after extraction,and the residue increased the amount of pore structure.They are more readily oxidized and the water-soluble yield reached the highest 68.15% and 50.34% at 40?,respectively.Through the above research had shown that H₂O₂ is a good oxidizer.After Fe²⁺ added,the water-soluble and the alkali-soluble were increased with the oxidizing depolymerization of coal,and the loss of the organic matter in coal reduced.The extracts and residue have a higher reactivity and easily oxidized...