Experimental studies on gas-phase mercury oxidation removal and denitration of coal combustion with NH_4 Br addition

In order to remove gas-phase mercury and NOx from flue gas, experimental studies on flue gas mercury oxidation removal and denitration of Guizhou anthracite combustion with NH4Br addition were carried out. The influence of NH4Br addition on the ignition temperature and combustion characteristics was studied using a thermogravimetric analyzer. The effects of the NHaBr addition amount on gas-phase mercury oxidation and removal were investigated in a bench scale of 6 kW fluidized bed combustor （FBC）. Mercury concentrations in flue gas were determined by the Ontario hydro method （OHM） and the mercury mass balance was obtained. Results show that the NH4Br addition has little influence on the ignition temperature of Guizhou anthracite. With the mercury mass balance of 95.47%, the proportion of particulate mercury Hg^p, gaseous mercury Hg^0 and Hg^2＋ are 75.28%, 11.60% and 13. 12%, respectively, as raw coal combustion. The high particulate mercury Hg^p in flue gas is caused by the high unburned carbon content in fly ash. When the NH4Br addition amount increases from 0 to 0. 3%, the concentration of gaseous Hg^0 and Hg^2＋ in flue gas decreases continuously, leading to the Hg^p increase accordingly. The oxidation rate of Hg^0 is positively correlated to the Br addition amount. It demonstrates that coal combustion with NH4Br addition can promote Hg^0 oxidation and removal. NOx concentration in flue gas exhibits a descending trend with the NHaBr addition and the removal rate reaches 17.31% with the addition amount of 0.3%. Adding NH4Br to coal also plays a synergistic role in denitration.

Additivity of pore structural parameters of granular activated carbons derived from different coals and their blends

A series of granular activated carbons （GACs） were prepared by briquetting method from Chinese coals of different ranks and their blends, with coal pitch as the binder. Pore structural parameters including BET specific surface area （SBEr）, total pore volume （Vr） and average pore diameter （da） were measured and cal- culated as well as process parameters such as yield of char （CY） and burn-off （B）. The relationship between the pore structural parameters of the GAC from coal blend （BC-GAC） and the ones of the GACs from corresponding single coals （SC-GACs） was analyzed, in which an index, the relative error （δ）, was presented to define the bias between fitted values and experimental values of these parameters of the BC-GACs. The results show that the BC-GAC keeps qualitatively the pore structural features of the SC-GACs; as concerned as the quantitative relationship, the pore structural parameters of the BC-GAC from coal blend consisting of non-caking coals can be obtained by adding proportionally the pore structural parameters of the SC-GACs with a less than 10%. Meanwhile, for the BC-GAC from coal blend containing weak caking bituminous coal, the δ increases up to 25% and the experimental pore size distribution differs greatly from the fitted one.

Coal-derived humic acid for application in acid mine drainage(AMD)water treatment and electrochemical devices

In this research work,isolation of humic acid from coal of Northeastern region of India is reported.The study is also targeted for application of the coal-derived humic acid in acid mine drainage(AMD)water treatment and electrochemical devices.All the obtained results are compared with the standard humic acid and examined the formation of humic acid from the coal.The isolated coal-derived humic acid is found to be high degree of humifications and relatively stable up to about 200℃.The FTIR study indicates the formation of metal-humic acid complexes.On treatment with acidic water(AMD),the coal-derived humic acid was found to have the ability to remove toxic metal such as(in order)Pb>Cu>Zn>Cd.In addition,the preliminary electrochemical properties of the isolated humic acid are also discussed in the paper.The specific capacitance of the isolated coal-derived humic acid via cyclic voltammetry and charge-discharge analysis is found to be 7 mF/g at scan rate 10 mV/s and 22 mF/g within the potential window 0.4 V,respectively.The charge-discharge cycles are stable for more than 1000 cycles within the potential window 0.4 V.This study will create a new pathway for the further research in this field.

煤层气利用清洁发展机制项目实例研究

本文详细论述了"淮南潘三矿煤层气利用清洁发展机制项目",并对煤层气清洁发展机制项目开发的关键部分——项目设计文件进行了深入分析和研究,为其他煤层气清洁发展机制项目的开发提供了有价值的参考。

过载补汽技术在大型汽轮机中的应用

介绍了过载补汽阀的结构及技术特点,以某600MW机组为例,定量分析了过载补汽结构对机组性能的影响。结果表明:采用补汽阀后,机组电功率增加38.949MW,提高约6.40%;但机组热耗率增加约59.2kJ/(kW·h),经济性降低约0.78%;汽轮机高压缸效率下降约1.96%。因此,在夏季或其他用电高峰期,采用补汽阀牺牲微量经济性,以保证机组出力是安全可行的。