粉煤成型技术研究进展

综述了国内外型煤技术研究现状,针对我国煤炭机械化开采过程中的粉煤利用难问题,提出了粉煤成型利用的必要性。总结了粉煤成型影响因素、型煤粘结剂及粉煤成型机理研究进展,研究表明:粉煤的性质、成型水分、煤料粒度、成型工艺、成型压力、粘结剂性质及添加量等对粉煤成型有很大影响;提出了粉煤无粘结剂成型过程假说和粉煤有粘结剂成型理论,为粉煤成型利用技术开发提供了理论基础。     

粉煤成型机理研究进展

综述了粉煤成型机理研究进展。褐煤无粘结剂成型机理有沥青、腐植酸、毛细孔等多种假说,这些假说都认为,煤“自身粘结剂”的丰厚 成型的重要基础;粉煤在粘结剂成型过程中,煤与粘结剂间相互润湿是成型的前提条件,进而依靠内聚力和粘附力使粉煤成型。本项研究将为开发粘结剂及成型新工艺提供理论依据。     

以聚乙烯醇为粘结剂制备成型活性炭的研究

以粉末活性炭为原料、聚乙烯醇(PVA)为粘结剂制备了成型活性炭,考察了粘结剂的比例,后处理时间,成型压力等对吸附性能和抗压强度的影响。结果表明,影响碘吸附性能的因素依次为:粘结剂的比例>后处理时间>成型压力>后处理温度;影响抗压强度的因素依次为:粘结剂的比例>后处理温度>后处理时间>成型压力;最佳制备条件为:粘结剂的比例为15%,成型压力为80MPa,后处理温度为200℃,后处理时间为30m in。     

原料煤粒度对型煤性能的影响

阐述了采用不同成型工艺和使用不同变质程度煤成型时,原料煤粒度对型煤强度的影响。无粘结剂高压成型时,随着煤的粒度的减小,型煤强度增大;有粘结剂低压成型时,无烟煤和烟煤的粒度可适当偏大,褐煤要保持较小的成型粒度。粒度分布对于型煤强度的影响较大。     

天然气储存用多孔炭的研究 Ⅱ.粉状多孔炭的成型及其二次活化

以酚醛树脂、煤焦油沥青为粘结剂对由大庆石油焦制得的粉状多孔炭进行成型实验,并对成型后的多孔炭用水蒸气进行二次活化,结果表明:粘结剂为煤焦油沥青,粘结剂与粉状炭质量比为1:2,成型温度为150℃时成型效果较好;水蒸气用量为7.0 mL/min,活化温度为800℃,活化时间为1 h的条件下,二次活化效果较好。     

陶瓷注射成型中水萃取脱脂粘结剂体系的相容性研究

提出了陶瓷注射成型水萃取脱脂粘结剂组分相容性的三大判断方法:溶解度参数法、热力学计算法、扫描电子显微镜法,以评判水基注射料的相容性,为陶瓷注射成型水萃取脱脂粘结剂的相容性提供了理论依据以及评判标准。并以聚乙二醇(PEG)/聚乙烯醇缩丁醛(PVB)以及聚乙二醇(PEG)/聚甲基丙烯酸甲酯(PMMA)两个水基粘结剂体系为例进行说明,讨论了陶瓷注射成型粘结剂的相容性对注射料流动性及水萃取脱脂速率的影响。     

型煤粘结剂概述

型煤粘结剂是成型技术的核心部分，对型煤质量，生产成本等起着举足轻重的作用，多年来通过深入研究，多种型煤粘结剂被开发，有利地促进了成型技术的发展，概述了国内外型煤粘结剂开发利用现状。     

晋城高强度防水气化型煤的研究

研究出ＭＪ１０粘结剂及ＭＪ１０－ＭＪ１１复合粘结剂,并用于晋城粉煤及其他几种粉煤,制出了高强度防水型煤,革制备工艺简便,不需要烘干工序,ＭＪ１０－ＭＪ１１复合粘结剂用于晋城粉煤成型,已取得了性成型和气化试验的成功,为发展可长途运输的气化型煤提供了技术途径。     

羟基磷灰石的制备、X-ray衍射表征和成型工艺探讨

以沉淀法合成羟基磷灰石（简称HAP）粉末，对生坯进行单向干压成型，设计正交实验，探讨了各主要因素（烧结温度、烧结保温时间和粘结剂）对成型过程的影响。实验结果可知HAP粉末成型的最佳条件为：烧结温度1100℃．烧结保温时间3小时，粘结剂为聚乙烯醇。     

生物质热解炭成型特性研究

通过将核桃壳热解转化为生物质热解炭并确定最佳制备温度,随后将生物质热解炭压缩成型,分析成型过程影响因素及成型品质。结果表明,600℃时产生的生物质热解炭与原料相比,挥发分含量降低70.21%,固定碳含量增加68.83%,热值达到29.16 MJ/kg;随着水分和成型压力的增加,成型炭的抗压强度先增大后减小;粘结剂种类影响成型炭的品质特性,采用复合粘结剂可保证成型炭冷热态强度,控制灰分含量;成型可改善热解炭燃烧特性,成型炭燃烧温度区间广,活性高且燃烧较为均匀,是一种更为理想的生物燃料。     

甲烷在成型前后活性炭上吸附的初步试验

通过对比试验,分析成型对活性炭储存甲烷特性的影响。首先,应用丙烯酸甲酯乳胶黏合剂对活性炭SAC-02成型,在温度区间268.15～338.15 K、压力范围0～15 MPa测试甲烷的吸附等温线;通过确定吸附量和等量吸附热,比较甲烷在成型前后活性炭上的吸附平衡。其次,测试储罐吸附床中心在室温、4个压力（6.5 MPa、5.5 MPa、4.5 MPa和3.5 MPa）下快速充放气过程的温度变化,分析成型对吸附过程热效应的影响。结果表明,成型活性炭的密度增大、比表面积减小、单位质量吸附剂上的甲烷吸附量减小;甲烷在成型前后活性炭上的等量吸附热均处于13～20.5kJ·mol^-1;成型活性炭吸附床中心温度在充放气过程中的变化幅度和变化速率均增大。比较试验结果时发现,选用黏合剂成型须综合考虑其对吸附床热导率、传质阻力及吸附剂微观结构的影响。     

活性炭吸附甲烷和甲苯的分子模拟研究

以石墨片微元构建的多孔碳材料作为活性炭的结构模型,采用巨正则蒙特卡罗方法(GCMC)和分子动力学方法(MD),从分子层面研究甲烷和甲苯在活性炭中的吸附和扩散特性. 结果表明,石墨片微元大小对多孔碳材料吸附甲烷和甲苯有一定影响,37个碳环构成的多孔碳材料是最佳的吸附结构;甲烷气体在活性炭材料中扩散较快,甲苯在活性炭中扩散较慢,随碳环碳原子数增加,气体在多孔碳材料中的自扩散系数逐渐增大;引入基团会使最优密度向高密度方向偏移,用不同基团表面改性的吸附量顺序为羟基>氨基>羧基>未改性,基团引入会改善材料的孔结构,有利于吸附量的增加.     

煤矿瓦斯气中低浓度CH4吸附富集研究

煤矿通风口处瓦斯气的CH₄浓度太低无法回收利用，只能排往大气中，既浪费能源，又污染环境。在活性炭吸附存储CH₄的基础上，对活性炭选择性吸附富集CH₄进行了初步研究。考察了多种吸附材料在常温和常压下对瓦斯气中低浓度CH₄的选择吸附能力，并关联了吸附材料结构参数和吸附性能之间的关系。实验结果表明，活性炭对低浓度CH₄有较强的吸附性能，孔径是决定活性炭能否选择性吸附CH₄的主导因素，而微孔比表面积及微孔孔容是次要因素。氧化改性不利于活性炭对CH₄的吸附，高温处理过程是获得高吸附性能活性炭的有效手段。     

Activated carbon monoliths for methane storage: influence of binder

In the present work, the agglomeration of a high adsorption capacity powdered activated carbon suitable for methane storage has been studied. Activated carbon monoliths have been prepared using the starting activated carbon and six different binders. Porous texture characterization of all the monoliths has been carried out by physical adsorption and helium density. Experimental methane adsorption capacity and delivery values have been obtained for all the samples. The results show that the adsorption capacities of the activated carbon monoliths are reduced with respect to the starting activated carbon. In addition to the adsorption capacity and delivery, the monolith density is also a crucial parameter for methane storage applications. This parameter has been obtained for all the samples. Moreover, the evaluation of the mechanical properties of the monoliths has been carried out with compression tests. According to our results, among all the binders studied, the one which produces monoliths with the best equilibrium between adsorption capacity and piece density has a methane delivery of 126 V/V. The important effect of the percentage of this binder in piece density and mechanical properties has been shown. Finally, a preliminary kinetic study of methane adsorption up to 4 MPa for the monoliths has shown that activated carbon monoliths do not present diffusional problems for adsorption of methane.     

炭化温度对兰炭基成型活性炭性能的影响

兰炭末加入黏结剂混合成型,经炭化和活化制得成型活性炭.利用TG-DTG对热解过程中成型料的炭化行为进行探讨;测试不同炭化温度的成型活性炭的收率、抗压强度和碘吸附值,采用N2吸附法和红外光谱对450℃炭化成型活性炭的孔结构及表面化学性质进行表征.结果表明,炭化温度越高,成型活性炭的收率越小,抗压强度越小,碘吸附值越大.经450℃炭化、800℃水蒸气活化60 min制得的活性炭表面具有大量的羟基、羰基和烃羟基等活性基团,比表面积为384.53 m2/g,属于中孔隙发达的活性炭.     

Adsorption of methane on corn cobs based activated carbon

Activated carbon was prepared with corn cobs and potassium hydroxide under optimized variables. Due to their botanical origin, corn cobs can be an excellent starting material to produce nanoporous carbon for natural gas storage. Samples with different BET surface areas were chosen to perform methane adsorption experiments. Methane adsorptions on corn cob based activated carbon were studied at four different pressures (500, 1000, 1500 and 2000 psi) and two different temperatures (298 K and 323 K) in a volumetric adsorption apparatus. The volume based methane adsorption results specified an ‘increase in the methane adsorption capacities of activated carbon with increasing surface area and showed that adsorption capacity of methane depends on pressure and temperature. The highest methane storage capacity was found to be 160 (v/v) at 298 K and 1500 psi. The applications include use in the transportation of natural gas, natural gas based vehicles, and adsorption of gas from landfills.     

天然气吸附剂研究进展

概述了国内外天然气吸附剂成型活性炭的开发情况和发展动态。介绍了粉体活性炭的制备方法:物理活化法和化学活化法,并比较了两种方法的优缺点。归纳了成型压力、胶黏剂添加量、后处理温度、后处理时间等工艺条件对吸附剂性能的影响。总结得出成型的关键在于对胶黏剂的选择及成型工艺条件。评述了成型活性炭的孔结构是影响甲烷吸附储存量的主要因素。     

Advances in the study of methane storage in porous carbonaceous materials

This paper presents an overview of the results of our research group in methane storage, in which the behaviour of different carbon materials in methane storage has been studied. These materials include physically activated carbon fibres (ACFs), chemically activated carbons (ACs) and activated carbon monoliths (ACMs), all of them prepared in our laboratories. These results have been compared with those corresponding to commercial ACFs, commercial activated carbon cloths and felts, and a commercial activated carbon.An in depth analysis (different raw materials, activating agent and preparation variables) has been done in order to obtain the carbon material with the best methane adsorption capacity by unit volume of adsorbent. The important effect of the micropore volume, micropore size distribution (MPSD) and packing density of the carbon materials in the methane adsorption capacity and delivery has been analysed. After this study, activated carbons with volumetric methane uptake as high as 166 v/v and delivery of 145 v/v have been prepared. In addition, ACM with methane uptake of 140 v/v and a delivery of 126 v/v has also been obtained.Moreover, the results corresponding to preliminary in situ small angle neutron scattering (SANS) study of CD₄ adsorption under pressure in different porous carbons and a zeolite are also included. These experiments have established SANS as a viable technique to investigate high-pressure methane adsorption. CD₄ adsorption at supercritical conditions produces changes in the SANS curves. The changes observed are in agreement with theoretical speculations that the density of the adsorbed phase depends upon the pore size.     

Determination of pore size distribution and adsorption of methane and CCl4 on activated carbon by molecular simulation

A combined method of grand canonical Monte Carlo (GCMC) simulation and statistics integral equation (SIE) for the determination of pore size distribution (PSD) is developed based on the experimental adsorption data of methane on activated carbon at ambient temperature, T=299 K. In the GCMC simulation, methane is modeled as a Lennord-Jones spherical molecule, and the activated carbon pore is described as slit-shaped with the PSD. The well-known Steele’s 10-4-3 potential is used to represent the interaction between the fluid molecule and the solid wall. Covering the range of pore sizes of the activated carbon, a series of adsorption isotherms of methane in several uniform pores were obtained from GCMC. In order to improve the agreement between the experimental data and simulation results, the PSD is calculated by means of an adaptable procedure of deconvolution of the SIE method. Based on the simulated results, we use the activated carbon with the PSD as the prototype of adsorbent to investigate adsorption. The adsorption isotherms of methane and CCl₄ at 299 K in the activated carbon with the PSD are obtained. The adsorption amount of CCl₄ reaches 20 mmol/g at ambient temperature and pressure. The results indicate that the combined method of GCMC and SIE proposed here is a powerful technique for calculating the PSD of activated carbons and predicting adsorption on activated carbons.     

甲烷在石墨烯和活性炭上的吸附

以研制新型吸附式天然气(ANG)吸附剂为目的,比较了甲烷在石墨烯和活性炭上的吸附平衡。首先,在温度区间273~293 K、压力范围0~8 MPa,测试甲烷在比表面积分别为300和2074 m²·g^-1石墨烯和活性炭上的吸附平衡数据。其次,应用格子理论导出的通用吸附等温方程,通过吸附平衡态能量分析及10-4-3相互作用势函数求解,确定甲烷分子在石墨烯平面和活性炭上的最大面密度、受到的壁面吸附作用势及其在吸附层内的作用能。结果表明,在相同温度下,吸附甲烷分子在石墨烯上吸附层内的相互作用能较其在活性炭上的大,甲烷分子在石墨烯平面上的集聚更为密集。提高石墨烯的比表面积将有效提高甲烷在其上的吸附容量。