导　　师： 马晓迅

学科专业： 081701

授予学位： 硕士

作　　者： ;

机构地区： 西北大学

摘　　要： 以煤热解为基础的多联产技术,作为煤洁净利用的重要方向之一,对煤碳的高效利用有重要意义。陕北低变质烟煤储量丰富,针对其低硫、低灰、低磷和高挥发分的特点,本课题组提出了煤热解-半焦气化耦合工艺。该工艺以煤热解为基础,对所得半焦再气化,并循环利用气化过程产生的气体及气体显热,提供给热解过程,得到合成气及高附加值的焦油产品,从而实现煤的分级利用及经济效益的最大化。本文以该工艺为中心,对陕北低变质烟煤府谷煤进行热解,并对热解半焦进行了气化研究。研究结果主要包括： 1.在粉-粒流化床中对府谷煤进行了快速热解实验。随着热解温度的提高,热解产品中,半焦产率从80.45/%/(ad/)降到59.34/%,煤气产率单调增加,焦油产率先增后减,在650℃时有最大焦油产率12.09/%/(daf/)；H2气氛下热解焦油产率达到16.67/%/(daf/),并促进了其向轻质化发展,C02气氛下明显降低了焦油的产率,但提高了煤气中CO的产率； 2.用自动吸附仪研究了热解半焦的孔隙结构,并用粉-粒流化床研究了热解所得半焦的CO2气化活性。不同热解温度所得半焦比表面积和孔容都明显低于原煤；不同热解温度所得半焦中,650℃热解半焦有最大比表面积,且气化活性最大,850℃热解半焦也有较大比表面积,但气化活性较低；H2气氛下热解半焦比表面积和气化活性较其它气氛都要大； 3.用粉-粒流化床考察了操作条件对半焦气化的影响。半焦水蒸气气化过程中,气化温度的提高和水蒸气流量的提高都有利于煤气产率的提高,但当水焦比达到0.3mL//g时煤气产率已经增幅很小；当氧焦比为200mL//g时有着最佳煤气热值及最大CO和H2产率；C02的添加有利于CO和H2产率的提高,并可调配CO和H2的比例,当CO2//char大于500m L//g之后气体产率增幅已不明显。 As one of the important research directions on clean coal technology, coal pyrolysis poly-generation technology is significant in highly utilization of energy. It has an abundant reserve of sub-bituminous coal in north of Shanxi, so according to its characteristics of low-sulfur, low-phosphorus, low-ash and high-volatiles, the coupling technology of coal pyrolysis and char gasification was considered. In this process, the coal powder is first pyrolyzed, and then the char that obtained from coal pyrolysis gasified in the reactor, meanwhile the gas and gas sensible heat obtained from gasification be provided to the pyrolysis process, and synthesis gas and high value-added tar can be get. By such a coupling technology, coal can be grading used, and economic benefits can be maximized. Treating this process as a center, a series of experiment research of FG coal were studied, such as pyrolysis process, products analysis, char gasification, etc. Here is the mainly research results: According to the fast pyrolysis of FG coal experiments in powder-particle fluidized bed, the results show that:With the increasing of pyrolysis temperature, the products have some varying patterns as followings:the yield of char decreases from80.45/%to59.34/%/(ad/). Gas production rate monotone increases. The yield of tar increases first and then decreases, and reaches the maximum value of12.09/%/(daf/) at650℃. Besides, in H2atmosphere, tar yield reaches16.67/%/(daf/), which promotes the conversion to light fraction of tar, while in CO2atmosphere, the yield of tar is obviously increased, but CO yield increases. The AUTOSORRB-1C and powder-particle fluidized bed were used to study the surface structure and gasification reactivity of CO2on char that produced in pyrolysis. The results show that:At different pyrolysis temperatures, the specific surface area and pore size of char are significantly smaller than raw coal, and at650℃, pyrolysis char possess the biggest specific surface area, the char also can obtain the highest gasification reactivity. When at850℃, the char has a larger specific surface area, but gasification reactivity is lower. Besides, in the atmosphere of H2, char activity is higher than others. Powder-particle fluidized bed was used to research the effects of operating conditions on char gasification. In the process of char-gasification with steam, the results show that:the increasing of gasification temperature and steam amounts benefit the rise of the yield of gas. However, when H2O//Char reaches0.3mL//g, the amplitude of char conversation was low. Besides, when O2//Char is0.2L//g, gas calorific values optimal, and CO and H2get the maximum yield rate. Moreover, the addition of CO2not only contributions to the increase of CO and H2yields, also adjust the proportion of CO and H2. When CO2//char is over500m L//g, the increase of gas yield has been modest.

关 键 词： 粉 粒流化床 热解 半焦活性 气化

分 类 号： [TQ530.2]

领　　域： [化学工程]