我国煤炭的单位热值碳含量研究

针对我国目前不同煤种的单位热值碳含量底数不清,相关国家标准仅给了一个缺省值,单位热值碳含量指标参数过于宽泛的问题,调研了我国12家大型煤炭企业集团的碳含量数据,分析了全国各煤种的单位热值碳含量,对比研究了原煤和商品煤之间单位热值碳含量变化规律。结果表明,我国各煤种原煤的单位热值碳含量范围在24.0×10^-3~27.8×10^-3kg/GJ,商品煤为23.4×10-3~27.5×10-3 kg/GJ;原煤经过洗选后,除贫瘦煤、瘦煤和无烟煤外,其他煤炭的单位热值碳含量稍有减小;单位热值碳含量随着煤化程度的升高,先减小后增大。     

以煤为原料的合成氨工艺选择

对我国合成氨资源分析后 ,认为以煤为原料的氨厂仍有发展前景。提出了煤基合成氨工艺的选择原则 :烟煤型采用水煤浆气化 ,无烟煤或焦炭采用常压气化。重点介绍了常压气化主要工艺的选型 :有廉价氧气源的选择富氧造气 ,一般情况下采用常压间歇造气 ;尽可能采用全低变 ;有蒸汽来源的采用化学吸附脱碳 ,否则应选择物理吸附法 ,慎用变压吸附法 ;合成工段应从压力、塔结构及热回收方式等方面综合考虑。     

Enhancement of combustion efficiency with mixing ratio during fluidized bed combustion of anthracite and bituminous blended coal

In order to investigate the effect of mixing ratio of bituminous coal to blended coal on the enhancement of combustion efficiency, combustion experiments of blended coal with anthracite and bituminous are done in a laboratory scale fluidized bed combustor (10.8 cm ID and 170 cm height). The gross heating values of anthracite and bituminous coal used in this study are 2,810 cal/g and 6,572 cal/g, respectively. Experimental parameters are fuel feed rate, superficial gas velocity and mixing ratio of bituminous coal to blended coal. The combustion efficiency increases with the mixing ratio of bituminous coal due to the lower unburned carbon losses and higher burning velocity of bituminous coal. The rate of combustion in the combustor was increased with mixing ratio resulted from a higher burning velocity of bituminous coal. The measured combustion efficiency experimentally is about 3.5-12.4% higher than that of the calculated value based on the individual combustion of anthracite and bituminous coal under the same operating conditions. The optimum mixing ratio (MR) of bituminous coal determined is around 0.75 in this study. This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University.     

Carbon molecular sieves for gas separation processes

The development and commercialization of carbon molecular sieves (CMS) are closely connected with the development of pressure swing adsorption (PSA) processes for the separation of gases. It was already known in the 1960s that certain carbonaceous materials have a molecular sieving effect similar to that of the well known zeolitic molecular sieves. The effect was observed during basic research on anthracite and bituminous coal which are both known to be porous. However, the separation effect, e.g. for oxygen/nitrogen, was very small. It was not until the 1970s that large-scale production of uniform quality CMS suitable for commercial application in PSA processes was established. Nowadays, different types of CMS are successfully used in PSA plants, e.g. for the generation of nitrogen from air, for the production of methane from biogases, and for the recovery of hydrogen from coke oven and steam reforming gases^1–4.     

烘焙稻壳与不同煤化程度的煤共热解特性

稻壳在250 ℃/30 min条件下烘焙后,与无烟煤、烟煤和褐煤3种不同煤化程度煤进行不同比例的混合,混合物分别进行热重分析和高温共热解特性研究。结果表明：热重分析中,添加烘焙稻壳有利于提高无烟煤和烟煤的转化率,其提高率低于5%,但是不利于提高褐煤的转化率;高温共热解实验中,随着烘焙稻壳添加比例的提高,无烟煤和烟煤与烘焙稻壳共热解固体产物减少,气体产物增加,而褐煤与烘焙稻壳共热解固体产量增加,气体产量略有下降;烘焙稻壳的添加有利于共热解产气中H2组分的增加和CO2组分的减少,通过改变烘焙稻壳在混合物中的比例可以对共热解气体组分进行调节。     

生物质型焦生产工艺的研究

用生物质做粘结剂以干法冷压成型生产生物质型煤,再经炭化制得生物质型焦．研究了生物质（玉米秸、稻杆）配入量、成型压力、烟煤种类（气煤、气肥煤、肥煤、焦煤）及配入量对型煤和型焦的抗压强度的影响．实验结果表明,烟煤配入量和成型压力对型焦的抗压强度有显著影响,适宜的工艺条件为生物质配入量１８％,肥煤与无烟煤配比１：２,成型压力４６０ｋＮ．此外,分析了型焦和热解挥发物的组成和性质．     

变压吸附气体分离用煤基炭分子筛的制备研究进展

阐述了国内外应用于变压吸附分离气体的煤基炭分子筛吸附剂制备研究进展,总结了以褐煤、烟煤、无烟煤为原料,制备炭分子筛所采用的不同工艺方法及其特点;详细讨论了主要的制备工艺条件对煤基炭分子筛结构和分离性能的影响。     

无烟煤粉煤的利用问题

我国无烟煤产量近２．５亿吨，据无烟煤生产现状和煤质特性，主要问题是灰分高的无烟粉煤大量积压。利用无烟粉煤的优化顺序：作高炉喷吹燃料，工业型煤，炼焦配料，煤基活性炭和炭其它高附加值的产品原料等。     

调控炭化过程优化煤基硬炭负极储钠性能

我国煤炭资源丰富多样、价格低廉、分布广泛,将煤转化为新材料,是提高其附加价值和技术含量的有效途径。煤含碳量高、芳环结构丰富,热解炭化可制备钠离子电池硬炭负极材料。以新疆烟煤为碳源,采用低温热解复合高温炭化的两步过程,并调控相应工艺条件,研究了烟煤中间相的发展过程对硬炭结构及其储钠行为的影响。经研究发现,改变低温热解的温度区间、载气流速和升温速率,可以调节胶质体生成阶段内的分解和解聚反应,调节挥发分生成和逸出以及胶质体固化等过程进行的程度,从而调控硬炭的比表面积和石墨化程度等。在温度区间为350~550℃、载气流速为60 ml·min^-1、升温速率为1℃·min^-1条件下,炭化得到的硬炭负极可逆比容量和首周库仑效率最佳,在0.02 A·g^-1的电流密度下分别达到314.3 mA·h·g^-1和82.8%,良好的性能归因于煤基硬炭材料中有序结构和缺陷结构的协调和平衡。     

Preparation of SiC from acid‐leached coal gangue by carbothermal reduction

For the comprehensive utilization of coal gangue, acid‐leached coal gangue was used as silicon source and part of carbon source, low ash anthracite and degreasing cotton were added respectively as supplementary carbon source, SiC and SiC fiber were prepared by carbothermal reduction method accordingly. The results show that the main components in leached coal gangue are amorphous SiO₂ and carbon, which are suitable for the synthesis of SiC as raw materials. The synthesis temperature and holding time have important influence on the synthesis of SiC, and the optimum synthesis parameters for SiC are at 1550°C for 4 hours; under this condition, the yield of SiC is 78.27%, and the specific surface area is 6750 cm²/g. The results show that the resulting products are essentially composed of β‐SiC with a minor amount of α‐SiC. Besides, based on the carbon fiber transformation method, SiC fiber was prepared by using leached coal gangue and degreasing cotton as raw materials. Therefore, it can be concluded that leached coal gangue is a very effective and inexpensive source for preparing SiC, and more importantly, this work has important economic and social significance to realize waste recycling and control pollution.     

The effect of additive chemicals on the viscosity of coal-petroleum coke-water slurry fuel for a gasification process

As a preliminary study for the gasification of an anthracite and petroleum coke mixture, viscosity was measured at various temperatures (20–50 °C), slurry concentrations (60–70 wt%) and additive amounts (0–0.8 wt%) by using an LV-II type viscometer. In addition, four types of different additives, sodium naphthalene sulfonate, poly(methyl methacrylate), polypropylene and a polypropylene glycol based additive, were applied to Korean anthracite, petroleum coke and mixtures of these materials, and the viscosity data were compared. Viscosity dependency values for coal, anthracite, bituminous and sub-bituminous coal, were compared, and it was found that a high content of moisture and particularly ash increases CWS viscosity. The four types of additives tested in this research can effectively diminish the viscosity of coal and especially petroleum coke-water slurry by more than 70% to 95%, respectively. Moreover, the sodium naphthalene sulfonate-based additive reduced the viscosity of coal and petroleum coke-water slurry best, especially at concentrations in excess of 65 wt%. Based on these results, highly loaded slurry created by mixing anthracite and petroleum coke with additives was achieved.     

Coal and carbon nanotube production

Strong expectations exist for future use of carbon nanotubes as composite materials in a large number of industries. Production cost and control of the purity and properties of such materials will influence the impacts nanotubes on the chemical, computer and construction industries. As a source material, coal is cheap and abundant, and has unique chemical structure, therefore, may be utilised in the nanotube synthesis. In the present paper, the synthesis of carbon nanotubes using coal as source material has been reviewed. Current nanotubes production largely followed the way of the production for fullerenes, most relying on plasma arcing methods. Non-arcing methods were also explored by a number of researchers. Catalytic synthesis is highlighted which has significant potential in the future nanotubes production directly from coal. Mechanism of the nanotube formation from coal is different from that using carbon graphite. Coal properties in this case are important. Weak bonds and mineral matter in the coal play an important role in the formation of the nanotubes.     

烟煤和白煤结构表征及煤净洁添加剂的研制

运用远红外傅立叶变换光谱、超导核磁、光栅发射光谱、元素分析、X射线荧光光谱等分析测试手段,对烟煤和白煤的基本结构单元进行了表征。研究表明,白煤骨架中的芳环聚合度比烟煤大,碳支链较烟煤少;而且在白煤骨架中部分三维碳骨架中可能存在C—O—Si—O—C化学键。研制出了型煤净洁剂,将其与白煤粉、烟煤粉进行拌合,冷压后制成的型煤着火点降低,燃烧速度加快,不仅燃煤效率提高了20%,而且消烟除尘效果已达排放标准,有害气体二氧化硫降低了48%。     

典型煤炭燃料在民用解耦炉中的燃烧实验研究

实验对比研究了烟煤块状半焦及烟煤型煤等煤炭燃料在民用解耦炉中燃烧时的污染物排放特性和炊事能力,并基于解耦测试炉对烟煤型煤的特征尺寸进行优化,验证了解耦炉具对不同种类民用煤炭燃料的适应性。结果表明,民用解耦燃煤炉具特有的结构特征和通风方式有利于NOx和CO的同时减排。若在解耦炉中燃烧烟煤洁净型煤,可进一步实现对SO2和颗粒物(PM)的有效控制。型煤尺寸对炉具污染物排放影响显著,尺寸优化后的烟煤洁净型煤在解耦炉中稳定燃烧时NO, SO2, CO和PM的平均排放浓度按基准氧含量9vol%折算后,分别低于190, 300, 380和30 mg/m3,炊事功率可达1.65 kW。     

民用燃煤颗粒物及多环芳烃排放特性

民用煤的不完全燃烧是大气中颗粒物及其多环芳烃的主要排放源之一,对大气环境和人体健康均造成了严重危害。为了评价不同“煤炉匹配”方式对16种优先控制的高毒性多环芳烃（PAHs）排放的影响,研究了烟煤块煤、烟煤型煤、无烟煤型煤和兰炭4种不同燃料在代表性的3种民用炉具（正烧炉、反烧炉和解耦燃烧炉）中的颗粒物（PM）及其PAHs的排放特性。根据实验结果进一步计算了毒性当量,并与有关文献报道数据进行了对比。在解耦燃烧炉中,烟煤型煤PM和PAHs的排放因子（EF_PM 和EF_PAHs）（0.50 g/kg、403.2 μg/kg）分别是烟煤块煤（3.65 g/kg、989.6 μg/kg）、兰炭（1.08 g/kg、622.3 μg/kg）、无烟煤型煤（2.10 g/kg、148.3 μg/kg）的13.7%、46.3%、23.8%和42.3%、67.3%、282.3%,除了EF_PAHs高于无烟煤型煤之外,EF_PM 和EF_PAHs均明显低于其他煤种;以烟煤块煤为原料,在解耦炉中燃烧的EF_PM 和EF_PAHs（3.65 g/kg、989.6 μg/kg）分别是正烧炉（46.58 g/kg,16182.3 μg/kg）和反烧炉（6.00 g/kg,11749.4 μg/kg）的7.8%、60.8%和6.1%、8.4%,说明炉具燃烧形式对EF_PM和EF_PAHs的影响大于燃料种类;三种“煤炉匹配“方式（解耦炉+烟煤型煤、正烧炉+兰炭、正烧炉+无烟煤型煤）的EF_PM和EF_PAHs（0.50 g/kg、1.62 g/kg、1.32 g/kg和403.2 μg/kg、1196.5 μg/kg、66.5 μg/kg）均低于传统正烧炉+烟煤块煤（46.58 g/kg,16182.3 μg/kg）以及近年来大部分文献报道的数据（0.68~24.3 g/kg,680~137700 μg/kg）。结果表明,炉具燃烧形式和煤质特性均是影响EF_PM和EF_PAHs的主要因素,但高效的燃烧方式能够大幅降低煤质特性对污染物排放造成的影响,通过对炉具的不断改进以及采用合适的“煤炉匹配”技术,能够对我国储量巨大的烟煤资源合理、有效和清洁地利用。     

Solubilization of coals by reductive alkylation

Anthracite, bituminous and subbituminous coal when treated with naphthalene anion in tetrahydrofuran added negative charges to form the corresponding coal anions. Alkylation of bituminous and subbituminous coal anion with ethyl iodide resulted in the addition of 16 and 14 ethyl groups per 100 carbon atoms. The alkylated coals were 88 and 45% soluble in benzene. The molecular weights of the benzene-soluble portions of the bituminous and subbituminous coal were respectively 2000 and 700. An attempt to add alkyl groups to anthracite anion was not successful.     

配煤制备油气回收活性炭的研究

以太西无烟煤和大同烟煤为主要原料,通过改变原料煤配比和工艺条件制备油气回收活性炭。对制备的活性炭进行各项指标检测,并利用N2低温吸附法测定其孔隙参数。采用丁烷工作容量表征活性炭的油气吸附能力。结果表明,配煤法制备的活性炭BWC值较高,可达到11．1g／100mL;原料煤的配比对BWC值影响较小;活化时间较长有利于BWC值的提高;在高比表面积和较大的孔容条件下,活性炭的中孔数量对油气回收活性炭的制备尤为重要。     

Absorption of iodine by coal and lignite

The vapor pressure of iodine over mixtures of iodine and various coals has been measured at temperatures of 65–95°C. Lignite and bituminous coals exhibit similar behavior in their absorption of iodine whereas the behavior of anthracite coal is different. A region of constant vapor pressure occurs in the reaction between iodine and the bituminous coals and lignite. Complex formation between the iodine and coal is postulated.     

半焦-烟煤混燃特性及动力学分析

掺烧烟煤是解决低挥发分热解半焦着火难、燃尽差的一种有效方法。采用热重实验研究了半焦、无烟煤与烟煤混燃特性的差别,分析了混燃过程中的交互作用和反应动力学。结果表明：陕煤半焦的燃烧过程分为可燃质的燃烧和CaCO₃的分解两个阶段。半焦-烟煤混烧的主失重峰靠近燃料比接近的单燃料的DTG峰。半焦-烟煤混合燃料较无烟煤-烟煤混合燃料的综合燃烧特性更优。掺混烟煤比例越高,混燃的表观活化能越低,可燃性和综合燃烧特性越好。烟煤与半焦或无烟煤混燃过程中存在一定的交互作用,且无烟煤-烟煤的交互作用较半焦-烟煤更显著。可燃性指数和综合燃烧指数与燃料比呈负线性相关性,表观活化能E与燃料比呈正线性相关性。     

Simultaneous measurement of weight loss by DTG combustion and SO2-formation for different coals

Burning profiles and SO₂-formation profiles were measured simultaneously for four different coals by slowly heating coal samples in a flow of air in a thermobalance. The profiles of weight loss and SO₂ formation have the same shape with anthracite combustion. The SO₂-formation profiles of bituminous coals usually display two peaks that approximately correspond to the release of volatile matter and combustion of char in the burning profiles. No correlations could be found between either the types of sulphur present in the raw coals or the ratio of volatile matter to fixed carbon and the shape of the SO₂-formation profiles for the bituminous coals.