【作者】 吴幼青；

【导师】 高晋生；

【作者基本信息】 华东理工大学 ， 化学工艺， 2011， 博士

【摘要】 由于不同的形成过程,不同热解过程产物炭的理化性质不同,导致其气化反应特性也应该有所区别。为此,研究不同热解过程产物炭的理化性质及气化反应性,不仅可加深对它们的基本性质及碳的气化反应机理的认识,而且对进一步丰富炭素学科理论具有重要的现实意义。此外,我国石油焦的产量与日俱增,其合理有效利用成为急需解决的重要问题。为此,开展石油焦/水蒸气催化气化特性的研究,不仅可以丰富碳/水蒸气催化气化反应规律的认识,而且可以为石油焦用作气化原料提供基础数据和理论参考。本文的主要研究内容和结果如下：(1)在气相、液相和固相热解温度分别为1000～1200℃、350-500℃和1000-1600℃条件下,以各种气相、液相和固相含碳物料为原料制备了三种不同种类炭,使用SEM、XRD、FTIR、GC/MS和孔结构及比表面积测试仪等分析手段,对它们的理化性质进行了分析,并采用等温热重法对其C02气化反应性进行了研究,取得了一些新的认识：①气相炭和液相炭都含有一定量的可溶有机质,其中液相炭含有的可溶有机质相当多,这也是导致其气化活性低的最主要因素；②气相炭、液相炭和固相炭的碳微晶结构有序化程度都不高,但总体上三者之间有如下的顺序,即液相炭>气相炭>固相炭；③这三种炭的气化活性顺序总体上为气相炭>液相炭>固相炭。(2)在慢速升温及高温热解(950-1400℃)和快速升温和加压(0.1～3 MP)热解条件下,以工业延迟焦(石油焦和沥青焦)和煤(神华煤和兖州煤)为原料,分别采用高温马弗炉和自制的快速加压热解装置制备了各种慢速高温热解焦和快速加压热解焦,使用SEM、XRD和孔结构及比表面积测试仪等分析手段对各种焦的理化性质进行了分析,并采用等温热重法考察了各种热解焦的C02气化反应特性,结果发现：①煤焦和工业延迟焦在热解过程中比表面积的变化呈现相反的趋势；②高温热解总体上有利于提高工业延迟焦的气化反应性；③热解压力增加导致煤焦的气化活性增加,而导致工业延迟焦的气化活性下降；④工业延迟焦的气化活性远低于煤焦的气化活性,甚至低于天然石墨的气化活性。(3)以三种典型的农作物秸秆(稻草、麦草和棉花)灰为研究对象,采用XRF、XRD和SEM/EDS等分析手段对它们的理化性质进行了分析,并在自建的固定床气化反应装置上考察了这三种秸秆灰及K金属盐对石油焦/水蒸气气化的催化作用,结果发现：①高温下矿物质之间相互作用形成低共熔体,导致秸秆灰中具有催化作用的金属元素失去活性；②本文提出的计算CO和C02气化选择性的方法,可用于了解碳/水蒸气气化行为；③在各种钾盐和各种秸秆灰中,催化活性最好的分别是K2CO3和棉花秸秆灰,但其添加量几乎不影响气化产物的分布及CO和CO2的选择性。更多还原

【Abstract】 Due to their different formation processes, carbons from different pyrolysis processes possess of different pysyco-chemical properties, which results in some differences of their gasification characteristics. Therefore, It’s imperative for us to investigate physico-chemical properties and gasification reactivity of carbons produced in different pyrolysis processes, thus it can not only strengthen our understanding of their essential properties and the gasification mechanism of carbons, but also enrich the theory of carbon science.Furthermore, due to the increasing output of petroleum coke in our country, it is very imperative to utilize it in an efficient and reasonable way. Therefore, investigating the catalytic steam gasification of petroleum coke not only can enrich the understandings of catalytic steam gasification characteristics of petroleum coke, but also provide basic data and theoretic references for petroleum coke when it is used as the raw material of gasifiers. The main contents and achievements of this study were summarized as follows.(1) Three different carbons were separately prepared from gas-phase, liquid-phase and solid-phase carbonaceous materials at the corresponding pyrolysis temperatures of 1000～1200℃(gas-phase pyrolysis),350～500℃(liquid-phase pyrolysis) and 1000～1600℃(solid-phase pyrolysis). Physico-chemical properties of the three carbons were investigated by SEM, XRD, FTIR, GC/MS, a surface area and porosity analyzer, etc. and their CO2 gasification reactivity was also investigated by an isothermal thermo-gravimetry. Some new cognitions were obtained as follows.①Gas-phase and liquid-phase carbons contained a certain amount of solvent-soluble organic matters. The solvent-soluble organic matters in liquid-phase carbons were of great aboundance, which mainly resulted in a low gasification acitivity of liquid-phase carbons.②The ordered degree of carbon crystalline structure of gas-phase, liquid-phase and solid-phase carbons were low, and the ordering of carbon crystalline structure among the three carbons was as follows:liquid-phase carbon> gas-phase carbon> solid-phase carbon.③The ordering of gasification acitivities of the three carbons was as follows:gas-phase carbon> liquid-phase carbon> solid-phase carbon.(2) Various slow and rapid pyrolysis chars were prepared separately from industrial delayed cokes (petroleum coke and pitch coke) and coals (Shenhua and Yanzhou coals) at the corresponding pyrolysis conditions of high temperatures (950～1400℃) and high pressures (0.1～3 MP), respectively using a high-temperature muffle and a pressurized pyrolysis set-up. Physico-chemical properties of various resultant chars were investigated using SEM, XRD and a surface area and porosity analyzer so on, and their CO2 gasification reactivity was also investigated by an isothermal thermo-gravimetry. The following results were obtained.①Effects of pyrolysis condition on BET surface areas of coal chars are opposite to those on BET surface areas of industrial delayed cokes.②High pyrolysis temperatures, as a whole, were favorable to elevate the gasification acitivity of industrial delayed cokes.③Increasing pyrolysis pressures resulted in the increase of the gasification acitivity of coal chars and the decrease of that of industrial delayed cokes.④The gasification acitivity of industrial delayed cokes was far lower than that of coals and even lower than that of natural graphite.(3) Physico-chemical properties of the ashes from three typical crop straws (rice straw, wheat straw and cotton straw) were investigated by XRF, XRD and SEM/EDS, etc. and the catalytic steam gasification characteristics of petroleum coke, which were catalyzed by various K salts and the three ashes, was investigated using a fixed-bed gasification set-up. The following results were obtained.①At high temperatures, various minerals reacted each other to form amorphous compounds, resulting in the deactivity of metals from straw ashes.②A proposed method for calculating the selectivity towards CO and CO2 could be used to understand the steam gasification behaviours of carbons.③Among various K salts and straw ashes, K2CO3 and the ash from cotton straws respectively had the highest catalytic activity. There were no effects of their contents on the distribution of gas products and the selectivity towars CO and CO2.更多还原