【作者】 孙晓慧；

【导师】 方梦祥； 邱坤赞；

【作者基本信息】 浙江大学 ， 动力工程及工程热物理， 2023， 硕士

【摘要】 煤气化技术是洁净煤技术中的重要应用方向,为了高效利用煤炭资源,近年来,煤转气、煤转油等多元化开发利用技术快速发展。煤气化过程中,煤中含有的无机矿物质在高温条件下转变为煤渣,我国每年气化工艺产生了大量气化粗渣和气化细渣,煤气化渣的综合利用一直是许多煤炭企业和社会各界高度关注、急需解决的问题。为此,本论文提出将煤气化细渣用做燃料进行利用的方法,重点对气化细渣的燃烧特性进行研究。本文首先对气化细渣的燃烧动力学进行研究。通过热重实验研究气化细渣与煤、稻壳不同比例混燃的燃烧特性,根据热重实验结果计算着火点、燃尽温度等燃烧特性参数,并使用Coats-Redfern方法计算活化能、频率因子等动力学参数。通过计算发现,气化细渣和煤的比例为3:7时,综合燃烧特性指数较高;气化细渣和稻壳掺烧时,燃烧着火点显著降低,燃烧特性指数显著提高,气化细渣和稻壳的比例为3:7时,燃烧所需活化能较低。其次,为探究气化细渣燃烧产生的污染物排放特性,在固定床恒温燃烧实验系统上,研究了不同燃烧温度（800℃、1000℃）、不同掺烧比（30%、50%、70%）和不同掺烧物质（煤、稻壳）对燃烧生成NO_x、SO₂的影响。结果表明,升高温度会导致NO、SO₂的排放量增加。煤和气化细渣掺烧,气化细渣比例增大,燃烧污染物中NO_x、SO₂的排放量明显降低;稻壳和气化细渣燃烧,稻壳比例增大,可以有效降低SO₂的排放量,并提高气化细渣的燃烧性能。最后,在浙江大学青山湖能源基地2MW循环流化床燃烧实验系统上进行燃烧实验,分析不同实验工况下气化细渣的燃烧实验结果,形成气化细渣循环流化床独立稳定燃烧方案,为工业上大规模处理利用气化灰渣提供技术支持。更多还原

【Abstract】 Coal gasification technology is an important application of clean coal technology.In order to utilize coal resources efficiently,diversified development and utilization technologies of coal such as coal to gas and coal to oil technology have been greatly enhanced in recent years.In the process of coal gasification,inorganic minerals contained in coal are transformed into slag under high temperature conditions.In China,gasification process produces a large amount of gasification coarse slag and fine slag every year.The comprehensive utilization of coal gasification slag has always been a problem that many coal enterprises and the whole society pay close attention to and urgently need to solve.Therefore,this thesis proposes a method to utilize coal gasification slag as fuel and focus on the combustion characteristics of it.In this paper,the combustion kinetics of gasification fine slag is firstly investigated.The combustion characteristics of gasification slag mixed with coal and rice husk in different proportions are studied by thermogravimetric experiments.Combustion characteristics parameters such as ignition point and burnout temperature are calculated according to the results of thermogravimetric experiments,and kinetic parameters such as activation energy and frequency factor are calculated using Coats-Redfern method.It was found that the higher comprehensive combustion characteristics index was achieved when the ratio of gasification slag and coal was 3:7.When gasification slag and rice husk were co-firing,the combustion ignition point was greatly reduced and the combustion characteristics index was greatly improved.The lower activation energy was achieved when the ratio of gasification slag and rice husk was 3:7.Secondly,to investigate the pollutants emission generated by the combustion of gasification fine slag,the experiment was carried out in a fixed-bed constant temperature combustion system.The effects of different combustion temperature（800℃,1000℃）,different blending ratio（30%,50%,70%）and different blending materials（coal,rice husk）on the emission of NO_x and SO2 were studied.The results show that the increase of temperature leads to the increase of NO and SO₂ emissions.When coal and gasification fine slag are co-firing,the proportion of gasification fine slag increases,which can significantly reduce the emission of NO_x and SO₂.When rice husk and gasification fine slag are co-burning,the proportion of rice husk increases,which can effectively reduce SO₂ emissions and improve the combustion performance of gasification fine slag.Finally,combustion experiments were conducted on the 2MW circulating fluidized bed combustion experimental system at the Qingshanhu Energy Research Center of Zhejiang University.The combustion experimental results of burning gasification fine slag under different experimental conditions was analyzed.The scheme is proposed,which the gasification fine slag can be independently and stably burned in the circulating fluidized bed.This work can provide technical support for large-scale treatment and utilization of gasification ash in industry.更多还原