镍基、钴基添加剂对高硫焦煤热解过程中硫迁移行为的影响

发布时间：2018-08-01 08:59

【摘要】：随着煤炭资源的大幅度开采利用,优质炼焦煤资源日益短缺,高硫煤等非优质煤资源储量相对较大,但硫含量高的特点在一定程度上限制了其利用。为了缓解当前优质炼焦煤资源紧缺的问题,在保证焦炭质量的前提下,利用现有的高硫炼焦煤资源,合理调控高硫煤在炼焦过程中硫分的分布行为,有效降低焦中硫的比例,既能扩大炼焦用煤种类,又能有效降低焦炭生产成本。煤中硫主要分为无机硫和有机硫,无机硫可以通过浮选等传统物理方法脱除,而有机硫比较难脱除。基于此,本文选取一种富含有机硫的高硫焦煤,期望通过加压浸渍的负载方法向煤中引入镍基添加剂和钴基添加剂,以达到合理调控煤中有机硫的热变迁。在固定床上进行原煤及负载添加剂煤样的程序升温热解实验,重点考察无机添加剂对煤中硫迁移转化过程的影响,得到的主要结果表现在以下几个方面:(1)镍基添加剂对高硫煤热解过程中硫变迁行为的影响:镍基添加剂对煤热解过程中硫变迁行为的作用受负载压力和金属盐浓度的共同影响。当金属盐浓度为0.1%时,镍对煤样0.1-0.5-Ni(镍基金属盐浓度为0.1%,负载压力为0.5 MPa制得的煤样)热解时含硫气体的释放有抑制作用,对其他负载煤样则表现为促进作用;当金属盐浓度较高时,镍对煤热解过程中含硫气体释放有促进作用;但是当负载压力为1MPa时,镍在煤热解过程中有一定的固硫作用,致使焦中硫含量增加。当负载压力一定,金属盐浓度不同,镍对煤热解过程中硫在气、固相分配的影响不同。当负载压力为0.1 MPa时,镍对煤样热解过程中含硫气体的释放只有促进作用,而与金属盐浓度大小无关,此时焦中硫含量均降低;当负载压力为0.5 MPa,金属盐浓度低时,镍对煤热解过程中含硫气体的释放表现出抑制作用,而金属盐浓度较高时,则表现出促进作用;负载压力为1 MPa时,镍对煤热解过程中含硫气体的释放只表现为促进作用,且随着金属盐浓度的增大,促进作用先增强后减弱。(2)钴基添加剂对高硫煤热解过程中硫变迁行为的影响:钴基添加剂对煤热解过程中硫变迁行为的作用与镍基额添加剂一样,同样受负载压力和金属盐浓度的共同影响。钴对煤热解过程中含硫气体释放表现为促进作用,与负载压力无关。当金属盐浓度为0.1%时,随着负载压力的升高,配钴基添加剂煤样热解过程中含硫气体的释放量先增加后减少,焦中硫含量则先降低后增加。而金属盐浓度为2%时,焦中硫含量均降低,但降低程度不同。负载压力一定,金属盐浓度不同时,除1-1-Co煤样外,其他所有煤样热解焦中的硫含量均不同程度降低。当负载压力为1 MPa,金属盐浓度为1%时,煤热解过程中含硫气体的释放量有所减少,且焦中硫含量也最低,说明该煤样热解过程中有更多硫迁移至焦油中。(3)两种无机添加剂对煤热解焦中硫含量影响的差异性分析。低金属盐浓度和高金属盐浓度下,两种添加剂对煤热解焦中硫含量的影响完全相反。当金属盐浓度为0.1%时,随着负载压力的升高,负载Ni基和Co基添加剂的煤焦中硫含量都呈现出先降低后升高的趋势,但Co添加剂比Ni添加剂的作用更显著。当金属盐浓度为2%时,虽然Ni基添加剂和Co基添加剂的煤焦中硫含量随着负载压力的升高,也表现出同增同减的趋势,但是Co添加剂降低煤焦中硫含量的效果却比Ni添加剂差。
[Abstract]:With the large mining and utilization of coal resources, high quality coking coal resources are scarce and the reserves of high sulfur coal and other non quality coal resources are relatively large, but the high sulfur content has limited its utilization to a certain extent. In order to alleviate the shortage of high quality coking coal resources at present, the existing high sulfur content is used to ensure the quality of coke, and the existing high sulfur is used. Coking coal resources can be used to rationally regulate the distribution of sulfur in coking process, effectively reduce the proportion of sulfur in coke, which can not only expand the type of coking coal, but also effectively reduce the cost of coke production. The sulfur in coal is mainly divided into inorganic and organic sulfur, and the inorganic sulfur can be removed by the traditional physical methods, such as flotation, and the organic sulfur is difficult to remove. In addition, based on this, this paper selects a high sulfur coking coal rich in organic sulfur, and expects to introduce nickel based additives and cobalt based additives into coal by pressure impregnation method, so as to achieve the reasonable regulation of the thermal change of organic sulfur in coal. The effects of additives on the sulfur migration and transformation in coal are mainly shown in the following aspects: (1) the effect of nickel based additives on the sulfur change behavior during the pyrolysis of high sulfur coal: the effect of nickel based additives on the sulfur change behavior in the process of coal pyrolysis is affected by the load pressure and the concentration of metal salt. When the concentration of metal salt is 0 At.1%, nickel has an inhibitory effect on the release of sulfur containing gas when the coal sample 0.1-0.5-Ni (the concentration of nickel base metal salt is 0.1%, and the load pressure is 0.5 MPa), and is promoted to other loaded coal samples. When the concentration of metal salt is high, nickel can promote the release of sulfur containing gas in the coal pyrolysis process; but when the load pressure is at the load pressure, In the process of 1MPa, nickel has a certain sulfur fixation process in the process of coal pyrolysis, resulting in an increase in sulfur content in the coke. When the load pressure is certain, the concentration of metal salt is different, the influence of nickel on gas and solid phase distribution is different in the process of coal pyrolysis. When the load pressure is 0.1 MPa, the nickel can only promote the release of sulfur containing gas in the coal sample pyrolysis process, but with the metal. The concentration of salt is irrelevant, and the sulfur content in the coke is reduced at this time. When the load pressure is 0.5 MPa and the concentration of metal salt is low, nickel inhibits the release of sulfur gas in the coal pyrolysis process, while the metal salt concentration is higher, while the load pressure is 1 MPa, the release of sulphur containing gas in the coal pyrolysis process is only shown. In order to promote the effect, and with the increase of metal salt concentration, the promotion effect first strengthened and then weakened. (2) the effect of cobalt base additive on the sulfur change behavior during the pyrolysis of high sulfur coal: the effect of cobalt base additive on the sulfur change behavior in the process of coal pyrolysis is the same as the nickel base additive, the same effect of the load pressure and the concentration of metal salt. The release of sulfur containing gas in the process of coal pyrolysis is not related to the load pressure. When the metal salt concentration is 0.1%, with the increase of the load pressure, the release amount of sulfur containing gas is increased first and then decreased with the increase of the load pressure. The sulfur content in the coke is reduced first and then increases. While the concentration of metal salt is 2%, the sulfur content in the coke is contained. When the load pressure is different, the load pressure is certain, the concentration of metal salt is not at the same time. Except 1-1-Co coal sample, the sulfur content in all kinds of coal sample pyrolysis coke is reduced in varying degrees. When the load pressure is 1 MPa and the concentration of metal salt is 1%, the release amount of sulfur containing gas is reduced in the process of coal pyrolysis, and the sulfur content in the coke is also the lowest. In the process of coal pyrolysis, more sulfur is migrated to tar. (3) the difference analysis of the influence of two inorganic additives on the Jiao Zhongliu content of coal pyrolysis. Under the concentration of low metal salt and the concentration of high metal salt, the effect of the two additives on the sulfur content in coal pyrolysis coke is completely opposite. When the concentration of metal salt is 0.1%, it is negative with the increase of load pressure. The sulfur content in coal char with Ni and Co based additives shows a tendency to decrease first and then increase, but the effect of Co additive is more significant than that of Ni additive. When the concentration of metal salt is 2%, the sulfur content in char with Ni base additive and Co based additive increases with the increase of load pressure, but it also shows the same increase and decrease, but Co additive. The effect of reducing sulfur content in coal char is worse than that of Ni additive.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ530.2

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