煤中易挥发有毒痕量元素及其在燃烧过程中的行为

本文综述了煤中易挥发有毒痕量元素汞、砷、硒在煤中的赋存形式 ,在燃烧过程中的蒸发和化学反应等行为 ,指出了在目前研究燃煤过程中有毒痕量元素所存在的问题和需要努力加强的研究方向     

煤炭在燃烧过程中的污染和发展煤的深加工利用技术

煤炭在燃烧过程中,污染严重。加大煤炭的深加工,发展煤的转化利用技术,提高煤炭的燃烧率,是解决大气污染的必经途径。     

煤及其灰渣中的汞

研究了东北、内蒙古东部煤炭中汞的含量分布以及煤中汞向燃烧产物中迁移的规律。煤中汞含量高于土壤,并和煤中全硫分及灰分呈显著正相关。煤中汞在锅炉飞灰中被富集,在底灰中被分散。飞灰粒径越小汞含量越高,显示表面富集特征;飞灰中90％以上的汞存在于＜0.125mm粒子上。飞灰中汞占煤中汞总量23.1％～26.9％,从烟囱排出的汞占56.3％～69.7％,燃煤排放的汞是大气中汞的重要来源     

煤中微量有害元素的挥发性

利用3 种热解反应装置(密闭模拟下落床、流动气氛模拟下落床和固定床)研究了 6种煤中 As、Pb、Cr、Cd 和 Mn等微量有害元素的挥发性随温度(300～1000℃)的变化规律,同时考察了热解装置的影响.结果表明,这 5 种元素的挥发性均随热解温度的升高而升高;6 种煤中 As、Pb、Cd均表现出与Cr 和 Mn相比具有较强的挥发性,但它们的挥发温度不同,其中 As 的挥发主要发生在 300～700℃,Cd 主要在 500℃以上挥发,Pb 主要在 800℃以上挥发.热解过程中,微量元素在半焦孔道内扩散时产生的反应是影响元素析出的重要因素之一.     

Market opportunities for coal gasification in China

Coal gasification is a technology that has been around for 200 yr. With the recent technology advances in the past 20 yr, it has become an option for the clean production of power and other energy forms. China will continue to be the largest user of coal in the world. Coal is the source of energy in almost every area of everyday life in China. This paper is an overview of the prospects of coal gasification in China. It discusses the opening of Chinese markets to more private sector participation. In particular the paper focuses on the energy sector and coal as the both an economic development variable and a factor in climate change. Clean coal technologies can be apart of the production cycle in China and hence can impact the Chinese economy in a positive manner as well as lower the current high levels of atmospheric pollution. Proven integrated gasification combined cycle (IGCC) technologies in new production methods and applications can provide China with its rising energy needs and reduce the SOX, NOX and particulates in the atmosphere. The results of IGCC can support the Chinese economy as it moves into the future.     

煤炭及其灰渣中的有机汞

采用8mol/L HCl浸提,巯基棉分离法测定了煤炭及其灰渣中的有机汞并探讨了它在燃烧过程中的迁移.15个省、市、自治区煤炭中有机汞含量的平均值为0.037mg/kg,占煤中总汞的18.8%.燃煤飞灰中有机汞平均值达0.045 mg/kg,占总汞28.1%.煤炭中的有机汞在燃烧过程中部分迁移到灰渣中,并明显富集,存在着排入大气的可能性.     

Microorganisms desulfurization of coal

A culture of Thiobacillus ferrooxidans strain T-4, isolated from Song Zao Coal Mining, China, is able to use pyrite from coal as a source of energy. The bacterial culture solution with 108 -109 cells/ml, pH 1.55 - 1.70 was employed in the nine coal samples with -200 mesh have been studied at initial pH 1.7.30℃ , 20-30% coal pulp density. The bacterial removal sulfur from coal in samples 3, 4, 6 and 7 were reduced to 1.05 - 1.33% and 86.11% of pyritic sulfur can be removed in 4-24 hours.     

Analysis of organic compounds in coal gasification wastewater

A procedure for analysis of organic pollutants in coal gasification wastewater was developed, including a series extraction steps at different pH, followed by LC separation or resin adsorption, then analyzed by GC or GC/MS. More than 200 organic pollutants in 22 categories were determined. CH2CL2 extraction at NaHCO3 presence was used to separate carboxylic acids with phenolic compounds in aqueous. Derivatization with acetic anhydride was used for analyses of mono-, di-, poly-hydroxyl phenolic compounds. 21 mono-hydroxyl phenols and 13 di-hydroxyl phenols were determined from the coai gasification wastewater samples. Derivatization with BF3-CH3OH was used for analysis of carboxylic acid. 17 mono-carboxyl, 4 di-carboxyl acids and 6 aromatic acids were determined from coal gasification wastewater samples.     

Wastewater and stormwater minimisation in a coal mine

This paper presents a case study on the application of cleaner production principles in the mining industry. The water balance prepared for the case study showed that less than 20% of the wastewater generated by the colliery is discharged off-site. The remaining 80% of the wastewater is recycled back into the colliery. Modeling of the stormwater system showed that 75% of the clean runoff becomes contaminated through poor management practices. It was also found that the present system of stormwater management causes the process wastewater management system to fail in wet weather. Improved process and stormwater management systems are proposed. Relatively simple alterations to the operation of the coal wash filtration dams are expected to reduce the periods of inefficient operation of these dams by 95% and the pumping cost by 30%. The use of stormwater diversion channels and retention basins reduces the overflow volumes of the process wastewater treatment dams in 5 year average recurrence interval (ARI) storms by 100%. The paper also includes several recommendations for reducing the production of process wastewater at source and off-site disposal of wastewater.     

Environmental problems in a coal mining area affected by coal fires --A case study in Ruqigou Coalfield, Ningxia, China

Ruqigou Coalfield, being one of the most important coal mining areas in China, has suffered coal fire problems for more than one hundred years. Due to coal fires, about 4.513 million tons coal resources has been lost each year, and apart from a large volume of CO2 delivered into air, environmental problems such as land degradation, land pollution and air pollution are also produced. Air pollution, as one related to coal fires, is the most dangerous problems for local people and has already led to vegetation pollution in this area. Land degradation is mainly induced with occurrence of land subsidence, fissures with due to coal mining/coal fires, and debris slide/flow. With development of opencast coal mining, a large volume of waste was produced, which is the major source of land pollution. All these environmental problems are associated with coal mining or coal fires and their comprehensive effects are deterioration of environment.     

煤炭生产的水足迹评价研究

水足迹是水资源占用的综合评价指标,能够量化人类活动对水资源和水环境的影响,为水资源的高效利用与可持续管理提供科学参考.本文在WFN水足迹评价方法和国际标准水足迹评价方法的基础上,提出了基于生命周期的包含蓝水足迹、灰水足迹和间接水足迹的能源系统水足迹评价模型.将此模型应用到煤炭生产,计算了我国单位煤炭生产的水足迹.研究结果表明,我国1 GJ煤炭生产的水足迹为0.19 m~3,水足迹的80%来源于采掘过程,从水足迹类型来看,灰水足迹占到了87%的比例.本研究为能源系统水足迹评价提供了方法理论,并可为以煤炭为原料或燃料的下游产品水足迹评价提供数据支撑.     

国内民用燃煤烟气中多环芳烃排放因子研究

模拟国内民用燃煤过程.确定燃煤排放烟气中PAHs的排放因子、PAHs在烟气气相与颗粒相之间的分配、特征排放谱以及不同燃烧方式的影响.结果表明:以15种母体PAHs加和计,燃煤排放因子的变化范围为71～882 mg·k8-1,排放因子和有毒PAHs组份排放量由高至低依次为烟煤、蜂窝煤和无烟煤,主要毒性成份存在于颗粒相中.PAH组份的气-固相分配比例与其饱和蒸汽压存在显著的正相关关系.燃煤类型和燃煤中挥发组份对烟气PAHs排放因子、气-固相分配以及排放谱分布具有决定性作用.另外,不同燃烧方式对燃煤排放因子也有一定影响,缺氧条件会导致排放系数升高.     

煤粉粒度对煤粉燃烧NOx排放的影响

通过数值模拟和试验研究，探讨了煤粉在一维热态试验炉内燃烧时，煤粉粒度对NOx排放特性的影响规律．研究结果表明：NOx的排放浓度与煤粉粒度的关系中，存在一个煤粉粒度临界值．当煤粉粒度小于临界值时，随煤粉粒度的减小，NOx的排放浓度减小；当煤粉粒度大于临界值时，随煤粉粒度的减小，NOx的排放浓度增大；无论在氧化性气氛中，还是在还原性气氛中，煤粉超细化后NOx的释放浓度均减小；煤粉高度细化后，褐煤NOx的排放浓度明显减少，无烟煤则变化不大模拟计算与试验结果较为吻合．     

Bow-tie分析在水煤浆气化工艺中的应用

水煤浆气化工艺开发到现在已经有30多年的历史。由于该工艺是在高温高压操作条件下,在炉内发生激烈的氧化还原反应,生成的水煤气属于易燃、易爆的气体,具有极高的危险性。近年来,我国连续发生了多起水煤浆气化工艺生产事故,如2006年8月21日,某公司水煤浆气化炉入口煤浆管线闪爆起火事故;2008年2月13日,某公司水煤浆气化装置煤浆管道爆炸事故。因此,如何保证水煤浆气化工艺的安全平稳运行成为一个迫在眉睫的问题。     

采煤塌陷地复垦的环境经济分析——以开滦煤矿为例

将环境经济学引入复垦活动的分析和评价，着重考虑了复垦的生态社会效益，复垦土地资源的价值、市场价格变化对复垦经济收益的影响和复垦效益对时间的依赖性，以期为复垦项目的选择和相关政策的制定提供经济方面的依赖和指导。     

2005年度中国燃煤大气硒排放清单

采用基于燃料消耗的排放因子法,按照经济部门、燃料类型、燃烧方式和除尘设施等将排放源进行分类,根据各省、市、自治区不同排放源类型的煤炭消耗量及其平均硒含量,建立了2005年中国燃煤大气硒排放清单.结果表明,2005年中国燃煤大气硒排放总量为1331.14t,排放量从大到小依次为山东(175.90t)、河北(111.79t)、河南(105.36t)、江苏(97.32t)、山西(84.66t)等,说明硒排放主要集中在中东部地区.大部分排放来自工业(576.60t)和电力(543.82t)部门,分别占排放总量的43.32%和40.85%,原煤燃烧排放占燃煤大气硒排放总量的90.07%.     

2005年中国燃煤大气锑排放清单

采用基于燃料消耗的排放因子法,按照经济部门(电力、工业、生活消费及其他)、燃料类型(原煤、洗煤、焦炭、型煤)、燃烧方式(层燃炉、煤粉炉、流化床锅炉等)和除尘脱硫设施(机械式除尘器、湿式除尘器、电除尘器、袋式除尘器等)等将燃煤排放源进行分类,根据各省、市、自治区不同排放源类型的煤炭消耗量及平均锑含量,建立了2005年中国燃煤大气锑排放清单.结果表明,2005年中国燃煤导致的大气锑排放总量约为530.86t,排放量超过30t的省份依次为贵州(49.28t)、湖南(45.96t)、河北(37.36t)、山东(35.12t)、安徽(30.92t),表明中国燃煤大气锑排放主要集中在中东部地区.大部分排放来自工业和电力部门,分别占排放总量的47.2%和39.9%.     

Environmental benefits of underground coal gasification

ＩｎｔｒｏｄｕｃｔｉｏｎＣｏａｌｉｓｔｈｅｍａｉｎｅｎｅｒｇｙｒｅｓｏｕｒｃｅｉｎＣｈｉｎａａｎｄｔａｋｅｓｍｏｒｅｔｈａｎ 70 %ｏｆｔｈｅｐｒｉｍａｒｙｅｎｅｒｇｙｒｅｓｏｕｒｃｅｃｏｍｐｏｓｉｔｉｏｎ.Ｂｕｔｔｈｅｅｎｖｉｒｏｎｍｅｎｔａｌｐｏｌｌｕｔｉｏｎａｒｉｓｅｎｆｒｏｍｃｏａｌｍｉｎｉｎｇ ,ｔｒａｎｓｐｏｒｔａｔｉｏｎ ,ａｎｄｂｕｒｎｉｎｇｉｓｂｅｃｏｍｉｎｇｍｏｒｅａｎｄｍｏｒｅｓｅｒｉｏｕｓ .Ｔｈｅｒｅｆｏｒｅ ,ｉｎｏｒｄｅｒｔｏａｃｃｅｌｅｒａｔｅｔｈｅｃｏｏｒｄｉｎａｔｅｄｄｅ…