This work presents a model of ash deposition growth in the ash hopper of utility boilers when the nozzles are tilted downwards. The model consists a comprehensive combustion code to predict the flow field, temperature field, the gas and solid combustion and the deposition growth behavior. The results show that burner tilting has a significant effect on the deposition in the ash hopper. The work indicates that the numerical model can be used to optimize the design and operation of pulverized coal-burning boiler equipped with tilting burner systems.

煤粉浓淡分离燃烧技术在低负荷稳燃、降低燃烧污染物排放等方面具有良好性能，得到广泛应用。由于四角切圆燃烧锅炉粉管布置要求，燃烧器前往往布置有弯头，弯头出口存在煤粉空气混合物速度和煤粉浓度分布的不均。该文采用试验和数值模拟方法，对一次风煤粉空气混合物流经弯头后形成的气、粉分布不均对浓淡分离器的工作特性的影响进行分析。试验和模拟结果表明，弯头结构和布置形式对煤粉浓淡分离器的分离效果、浓淡侧速度分布不均等都有重要影响。文中同时提出了具有前置弯头的浓淡分离器获得高分离效果及浓淡侧速度均衡的途径，为浓淡分离器的设计和运行提供参考。

在一台小型沉降炉上进行了氨水喷射还原烟气中NOX的SMCR（Selective Non-Catalytic Reduction）实验研究， 同时结合化学反应动力学模型研究了NH3还原NO过程中的关键影响因素，结果发现，过高的温度引起氨水的氧化， 过低的温度不利于NO 的还原，存在一个单一的温度区间，在该试验台上最佳的氨水喷射温度范围为850℃～1100℃，最高达到了82%的NO还原率；采用均相反应模型与试验结果进行了对比，在高温区吻合情况较好；当温度高于950℃时，NH3残留量可以忽略；NH2的两类支链反应对于整个反应起重要作用。

A novel particulate trajectory model (PTM) is developed to predict axial transport and dispersion of municipal solid wastes (MSW), based on the vector analysis on particle's gravity-induced axial displacement in a single excursion. Three parts of work are extended with respect to this PTM. First, the simplified formulas about mean residence time (MRT) and material volumetric flow (MVF) are derived by incorporating statistic-averaged analysis on all repeated excursions of solids within kiln into PTM. The correctional factors-et for MRT and ef for MVF-are introduced to improve the model's validity under such practical cases, i.e. irregular MSW existence or internal-structure presence. Reasonable agreement is obtained between the empirical formulas and experiments with correlation factor in excess of 90% for all runs. Second, a stochastic PTM is extended to predict the residence time distribution (RTD) curves of segregated MSW by considering the probability of the rolling distance of individual particle. As for MSW, the main cause of axial dispersion is the egregation of rolling distance of solids, due to variation of MSW components, shapes and sizes. Finally, the optimization model for geometry design of a laboratory-scale rotary kiln pyrolyser of MSW is presented and the corresponding optimum solutions are provided.

This paper focuses on sulfur removal technologies in industrial grate furnaces (IGF) and pulverized coal fired boilers (PCFB) with high flame temperature of 1200-1600 ℃. The SO2 reduction without sorbents during coal combustion, thermal stabilities of sulfation products, kinetics of sulfur retention reactions of sorbents, desulfurization processes, and sulfur removal under unconventional atmospheres at high temperature are reviewed. It is proposed that some powdered minerals or industrial wastes with effective metal components may be used as sorbents for sulfur removal to promote cost effectiveness. Because the main reason that results in low desulfurization efficiencies in IGF and PCFB is the thermal decomposition of the conventional sulfation product CaSO4 above 1200 8C, it is key to explore new sulfation products that are thermally stable at high temperatures. It is also necessary to study the kinetic catalysis of alkali and transitional metal compounds on sulfation reactions under the combustion conditions of IGF and PCFB. The two-stage desulfurization process, in which SO2 is captured by sorbents both in the coal bed and the combustion gas, is promising for IGF, especially with the humidification of flue gas in a water-film dust catcher. The staged desulfurization process combined with air-staged combustion, in which sorbents are injected into the primary air field and upper furnace to capture SO2 under reducing and oxidizing atmospheres, is promising for PCFB. Flue gas recirculation is also an effective desulfurization process under O2/CO2 conditions and can give a high desulfurization efficiency of about 80% in furnaces.