【作者】 袁中山；

【导师】 王树东；

【作者基本信息】 中国科学院研究生院（大连化学物理研究所） ， 化学工程， 2005， 硕士

【摘要】 本文对燃煤催化固硫及催化燃烧一体化技术的核心—一体化添加剂的配方设计及其催化固硫与催化燃烧机理进行了理论分析与实验研究,在此基础上开发出一种廉价易得的天然矿物一体化燃煤添加剂并进行了工业示范应用。理论推导了锅炉加钙固硫后热效率的修正计算式,分析了一体化燃煤添加剂在链条炉、粉煤炉和流化床锅炉等三种典型炉型中的燃烧固硫反应行为对锅炉热效率的影响,奠定了本技术应用的理论基础。进行了一体化添加剂的配方设计,以热重和高温燃烧固硫等实验手段考察了单组分金属化合物助剂Na2CO3、MgO和Fe2O3对CaO固硫的催化作用规律,发现多组分金属化合物助剂对CaO固硫具有协同催化作用,针对不同煤种及炉型提出了不同种金属化合物助剂的催化固硫方案。以粒子模型计算了催化燃烧固硫反应动力学参数,结合分析表征,提出了一体化添加剂中金属组分助剂Fe2O3对CaO固硫的催化作用机理:助剂Fe2O3催化了SO2转变为SO3这一过程,使固硫组分CaO的硫酸盐化反应表面化学反应速度常数k和有效扩散系数D增大;在固硫反应的产物层扩散控制阶段,Fe2O3的存在使得CaO晶粒团之间相互粘连的几率减小,减轻了固硫产物CaSO4的团聚,弱化了扩散作用的影响,从而减轻了CaO固硫反应的孔窒息效应。以热重法实验研究了一体化添加剂对三个煤种的催化燃烧作用并进行了民用蜂窝型煤实验验证,采用非等温燃烧反应模型计算了加入一体化添加剂前后煤的燃烧反应动力学参数,结果表明一体化添加剂的加入可提高煤的燃烧反应速率,归因于外加金属离子通过电荷迁移使碳表面的棱、角、缺陷等活性部位增加,加快了氧气的吸附速度,使反应活化能和频率因子降低。燃煤电厂130吨/小时粉煤锅炉的工业性脱硫试验结果表明,硫含量为1%左右的煤种使用一体化燃煤添加剂进行燃烧脱硫,其烟气出口SO2排放可下降67-74%,总固硫率为76-83%。热工测试结果表明,固硫后飞灰和炉渣中的含碳量均略有降低,机械未完全燃烧热损失减小,锅炉热效率下降值均在0.3%以内,体现了燃煤一体化添加剂催化固硫及催化燃烧的双重作用。更多还原

【Abstract】 In this paper, a series of integrated additives that have bifunction of catalysis and sulfur retention during coal combustion was developed and the mechanisms of integrated catalysis for sulfur retention and coal combustion were discussed. Based on the obtained results, a novel integrated additive composed of crude minerals and industrial wastes was developed and commercialized on a 130 ton/hr pulverised coal boiler in a power plant.The formulations for calculation of slag, flue gas compositions and heat efficiency of coal boiler in the presence of sulfur sorbents were modified. The influences on heat efficiency of boiler using integrated additives of catalysis and sulfur retention were discussed in detail regarding three different kinds of boilers of chain-grate stocker, pulverized boiler and fluidized bed boiler. And these results composed the foundation of the utilization of integrated catalysis for sulfur retention and coal combustion.The influences on sulfation reaction of CaO of promoters Na2CO3, MgO and Fe2O3 in integrated additives were investigated by the experiments of thermogravimetry analysis and high temperature combustion sulfation. Synergistic effect of multi-component promoters was put forward and the catalytic sulfation of different metallic compound promoters for different boilers was discussed. The kinetic parameters of CaO sulfation reaction with and without additives doped were calculated using the Particle Model. The results show that the catalytic promoter Fe2O3 in additive catalyzes the reaction of SO2 to SO3 and accelerates the sulfation reaction rate of CaO both for chemical reaction control region and diffusion control region. And in the diffusion control region of CaO sulfation reaction, the existing of Fe2O3 alleviates the aggregation of CaSO4 so that weaken the pore closure effect of CaO sulfation reaction.更多还原