云南褐煤成型工艺条件的研究与优化

运用有粘结剂冷压成型技术对云南褐煤压制成型,主要考察煤粒的粒级大小,粘结剂含量和成型温度对型煤的抗压强度和跌落强度的影响,并通过响应曲面法对褐煤成型的工艺条件进行了研究.研究结果表明,实验值和检测值相近,可以用拟合模型对型煤的跌落强度和抗压强度进行分析和预测,以确定最佳的成型工艺条件,为工业型煤的生产提供依据.     

内蒙古霍林河褐煤热力初步改质研究

针对褐煤水分高、易风化破碎、氧化自燃、利用率低等问题,采用热力脱水方法对内蒙古霍林河褐煤进行了实验室改质研究,分析了改质温度、停留时间、原煤粒径对褐煤改质效果的影响。结果表明:改质温度、停留时间对褐煤改质效果影响显著,原煤粒径对褐煤改质影响不明显,当处理温度为300℃,停留时间为20 min时,褐煤改质效果最好;此时,褐煤Mad降低了79.75%,H含量增加了153%,O含量降低了62.47%,C含量提高了72.46%,N含量增加了26.09%,Qgr,ad增加了108.50%,Qnet,M增加了161.86%;褐煤改质过程明显降低了煤中Mad和O含量,并使C含量和发热量大幅提高,改质效果明显,这将为褐煤热力改质的应用奠定基础。     

热水干燥技术处理舒兰褐煤的研究

介绍了热水干燥褐煤的方法及机理,在高压釜内加热干燥褐煤,可永久改变低阶煤的物理和化学性质,褐煤的最高内在水分显著下降,发热量提高,表面疏水性增强;利用干燥后的褐煤制备水煤浆,具有良好的成浆特性、流变特性及稳定性。     

国内外低阶煤(褐煤)干燥成型机应用及发展

阐述了国内外低阶煤(褐煤)干燥成型机的应用及其研究进展,对热压成型(HPU)技术、洛阳双勇无粘结剂热压成型技术、郑州鼎力无粘结剂褐煤成型技术等国内低阶煤成型技术和冲压成型工艺、冷干工艺、澳大利亚无粘结剂成型BCB技术、德国泽玛克辊压成型工艺等国外低阶煤成型技术作了介绍,分析了目前褐煤成型技术存在的主要问题。     

提高印尼褐煤成浆性的试验研究

采用流化床干燥的工艺方法对印尼褐煤进行干燥热处理改质试验,以改善褐煤的成浆性;试验结果表明,褐煤经过干燥后,吸水性显著降低,成浆性显著提高,褐煤浆浓度由改质前的48%提高到60%左右。     

褐煤干燥提质和无粘结剂成型技术的研究现状及进展

论述了褐煤中水分的存在形式,即褐煤中的水分主要由外在水分、内在水分和结晶水组成,其中外在水分较易脱除。介绍了国内外褐煤干燥提质技术、针对高水分褐煤干燥研发的新技术及与褐煤干燥相关的其他提质技术的研究进展,其中,新研发的褐煤干燥技术中,过热蒸汽流化床褐煤干燥技术(WTA)具有效率高、能耗低、安全等特点,在单位能耗方面具有明显优势。通过对褐煤无粘结剂型煤的成型工艺及型煤耐水性能的试验研究,说明褐煤无粘结剂成型技术制备的型煤样品质量良好,吸收水分的速率大大降低,热解与燃烧活性也有所下降。最后分析了褐煤无粘结剂成型机理,即主要有沥青假说、腐植酸假说、毛细孔假说、胶体假说和分子粘合假说5种。     

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。     

无烟煤粉的气流干燥操作小结

在水玻璃粘土煤球生产过程中,为了稳定粘结剂配比,控制好成型水份,和均匀捏合以制得高强度煤球,提高立式干燥炉的生产能力,必须将煤粉干燥到含水低于2％。     

褐煤干燥脱水提质技术现状及发展方向

为实现褐煤合理、高效利用,减轻褐煤利用中的环境污染,阐述了国内外褐煤干燥脱水提质技术现状,论述了国内褐煤干燥脱水提质技术工业化示范项目的进展情况,说明褐煤经干燥脱水提质处理后,可脱除褐煤中大部分水分,发热量显著提高,提质后的褐煤具有较高的附加值,便于运输、贮存及综合利用。针对褐煤干燥脱水提质过程中存在的烟尘排放量大、能耗高、余热难以回收利用、干燥褐煤成型率低、型煤易爆裂产生碎块等问题,从加强褐煤性质和干燥脱水基础理论研究、加强干燥工艺及其配套干燥设备的研发、加强褐煤干燥后产品利用技术研究3方面提出了褐煤干燥脱水提质技术的发展方向。     

褐煤干燥成型工艺技术综述

褐煤干燥成型技术是将成本低廉的富含水分的褐煤在一定温度下经脱水后转化成为具有类似烟煤性质的提质煤。提质后的褐煤更有利于综合利用、运输和贮存,且具有可观的经济价值。介绍了国外7种褐煤干燥工艺技术和褐煤热压成型技术;着重论述了管式间接干燥工艺和高压热压成型工艺的干燥过程、成型过程、工艺特点及优缺点;通过工艺设计数据、物料衡算基准和关键设备配置,例举了褐煤干燥成型工艺设计应用实例;分析和论证了褐煤成型过程的性能保证和安全性保障。对褐煤干燥成型生产装置进行了技术经济评价,结果表明：建设1套百万吨级的褐煤干燥成型工厂,其建设投资约为3.8亿元,型煤加工成本约为60元/t。     

宝日希勒褐煤的热压提质试验研究

介绍了气流干燥技术的优点,并利用HPU试验线对宝日希勒褐煤进行了热压提质研究。煤样热重分析表明宝日希勒褐煤适宜的干燥温度为105～371℃。通过分析干燥温度、给料频率对提质煤粉水分的影响及提质煤粉水分对型煤质量的影响,说明提质煤粉水分随干燥温度的升高而降低,随给料频率的增加而增大,宝日希勒褐煤适宜的干燥温度为220～320℃,给料频率为30～50 Hz;提质煤粉较适宜的水分范围为5%～13%,最佳水分为5%～8%,此时,型煤抗压强度可达900 N/个以上,落下强度超过80%。因此,以高温烟气为干燥介质,采用气流干燥技术对宝日希勒褐煤进行脱水干燥提质是可行的。试验结果为拓展宝日希勒褐煤的加工利用途径提供了依据,也为其他地区的褐煤提质提供参考。     

Experimental study on the effects of drying methods on the stabilities of lignite

The drying processes are always applied prior to the transportation or utilization of lignite, and result in notable changes in the stabilities of lignite. In this paper, the study on the effects of nitrogen and MTE drying process on the physico-chemical properties and stabilities of Zhaotong lignite was carried out. The briquettes produced by MTE drying in this study were 150 mm in dimension, and so had a much larger particle size than nitrogendried samples. Nitrogen adsorption, mercury intrusion porosimetry and scanning electron microscopy all suggested that drying was accompanied by the transformation of larger pores into smaller ones. Compared to nitrogen drying, the pore structures could be stabilized by the MTE process. The soluble salts were removed during MTE drying which resulted in the decrease in ash and the concentrations of some of the major metals.The removal of water enhanced the hydrophilicity of nitrogen dried samples, but did not affect the hydrophilicity of MTE dried samples. The moisture holding capacity of MTE dried samples reduced faster than nitrogen dried samples with the decrease of residual moisture content. Themoisture readsorption processes of MTE dried sampleswere strongly inhibited due to themuch larger particle size of sample produced byMTE drying than nitrogen drying. The susceptibility to spontaneous combustion, indicated by cross point temperature and self-heating tests, of nitrogen and MTE dried samples increased with the decrease of residual moisture content. The MTE dried samples are more liable to spontaneous combustion than nitrogen dried samples with the same residual moisture and particle size. However, the larger particle size of the MTE product made it more stable with respect to spontaneous combustion and also moisture readsorption.     

高硅灰酒糟基粉状活性炭成型及性能

以粉状白酒糟物理活化炭为原料,以羧甲基纤维素(CMC)、煤焦油和酒糟活性炭灰分碱处理溶出液为粘结剂,研究了高含Si灰生物质粉末活性炭的成型方法. 结果表明,单独以CMC和煤焦油作为粘结剂,在4.0 MPa成型压力下所制成型活性炭的侧压强度达120 N/cm,但其碘吸附能力低于400 mg/g. 利用酒糟基活性炭灰碱处理溶出液,仅添加少量CMC成型的活性炭达到相同侧压强度,吸附能力达600 mg/g以上,明显高于仅添加CMC或煤焦油成型的活性炭,以及原活性炭粉. 对成型活性炭进行了红外光谱、XRD及SEM表征,分析了其粘结机理.     

Conditioning of coal-enrichment waste with high moisture and ash content

The processing of coal-enrichment waste with high moisture and ash content is considered. Existing methods—filtration and thermal drying—are very complex and energy-intensive and have considerable environmental impact. An alternative is adsorption on lignite coke produced in the Krasnoyarsk region by thermal oxidation. Termokoks-KS lignite coke, which is low in ash and sulfur, resembles activated charcoal in its absorption properties. Experiments show that, when mixed with coal wastes, it produces a fuel blend characterized by lower ash content, satisfactory friability, and high energy yields. An industrial technology for such conditioning of coal wastes is described.     

Cast (Self-Flow) Ceramic Castables. 4. Spreadability of Molding Systems and Some Properties of Mullite – Silicon Carbide Ceramic Castables

The rheological properties of molding systems are shown to depend on the spreadability of the mixture under the action of its own mass; some of the factors influencing the self-flow are determined, namely, the moisture content, the content of the filler, and the temperature of the mixture. The described self-flow castables based on a mullite HCBS and a SiC filler have a porosity of 18% after drying and 16 – 16.5% after heat treatment. Their ultimate bending strength is 45 MPa and the ultimate compressive strength is 110 MPa, which is higher than those of the known refractories of similar compositions. The temperature of 4% deformation of mullite – silicon carbide refractory heat treated at 1350°C and having C _Vf = 0.4 is 1710 – 1720°C, which is 70 – 80°C higher than that of a similar material molded by pressing and heat treated at 1500°C.     

Experimental study of thermal fragmentation of lignite in drying process

Abstract

This paper investigated the thermal fragmentation of three lignite samples with temperature of 100?°C–200?°C and drying time of 0–90?min using the fixed bed reactor. The effects of a variety of factors such as temperature and drying time on fragmentation ratio were studied. The results showed that fragmentation ratio was positively related to temperature and drying time, and the degree of fragmentation was different for different lignite samples. Additionally, it was demonstrated that the point load strength remarkably decreased with the increase of temperature and drying time. The fragmentation ratio as a function of point load strength represented that lignite with higher strength had a lower fragmentation ratio, and the possibility of secondary fragmentation of dried lignite decreased with the increase of point load strength. Fragmentation ratio decreased with the increase of lignite density. The mineral matters of lignite significantly had influence on fragmentation. The mass inhomogeneity degree was given to depict the mineral element compositions. A fragmentation prediction equation was established based on mass inhomogeneity degree, which was associated with moisture content and ash content.     

蒙东褐煤热解技术工业应用进展

蒙东褐煤占我国褐煤储量的83%,是蒙东地区的主要能源。低温热解技术条件温和、产品用途广、经济效益高,是加工蒙东褐煤的主要途径之一。但由于褐煤块煤率低、含水量高、热碎严重等特性以及现行环保产业政策持续趋紧,使褐煤低温热解工业化项目存在原料利用率低、生产连续性差、环保不达标等问题。本文介绍了目前蒙东地区应用的热解技术包括低阶煤转化技术（LCC）、连续干馏热解定位提质技术（LCP）、带式炉低温干馏技术、GF-1型褐煤提质技术、SJ低温干馏方炉热解技术和气-固错流热解技术,分析了各项技术的运行情况、优势和不足。通过对比各项技术在原料要求、传热方式、熄焦方式、能量利用率和产品性质等方面的特点,明确了各项热解技术的炉型选择、原料煤粒度和热解产品利用等方向,提出了蒙东褐煤热解技术在工业化应用过程中需实现原料优化、能量优化、产品多元化和废弃物资源化的发展要求。     

CONTRACTION CHARAClFRlSTlCS OF MOLDED CERAMICS DURING DRYING

ABSTRACT

The characteristics of drvine and contraction (shrinkage) of molded ceramics were expenmentally studied to clarify the effects of drying conditions on contraction behaviors or deformation during drying processes. Mikawa-Shanshu clay molded into spheres or slabs was used as a sample which underwent convective drying by hot air.

Three periods of preheating, constanl rate and falling rate existed, and the contraction was observed mainly in the preheating and constanl rate periods for all samples. It is also observed that the behavior of ihe contraction of molded clay is inflienced significantly by drying conditions. The higher drying rate makes the contraction of clay more remarkable in the preheating and constant rate periods. This behavior could not be explained from the difference of the moisture content distribution among runs. However, it is suggested that the inside parts of molded ceramics may be subjected to the strong compressional stresses and the strain-stress in the sample would Influence the contraction behavior when he gradient of moisture content distribution becomes steeper with increase in the drying rate.     

CONTRACTION CHARAClFRlSTlCS OF MOLDED CERAMICS DURING DRYING

The characteristics of drvine and contraction (shrinkage) of molded ceramics were expenmentally studied to clarify the effects of drying conditions on contraction behaviors or deformation during drying processes. Mikawa-Shanshu clay molded into spheres or slabs was used as a sample which underwent convective drying by hot air.

Three periods of preheating, constanl rate and falling rate existed, and the contraction was observed mainly in the preheating and constanl rate periods for all samples. It is also observed that the behavior of ihe contraction of molded clay is inflienced significantly by drying conditions. The higher drying rate makes the contraction of clay more remarkable in the preheating and constant rate periods. This behavior could not be explained from the difference of the moisture content distribution among runs. However, it is suggested that the inside parts of molded ceramics may be subjected to the strong compressional stresses and the strain-stress in the sample would Influence the contraction behavior when he gradient of moisture content distribution becomes steeper with increase in the drying rate.     

Experimental study and energy analysis on microwave-assisted lignite drying

For value-added utilization of high-humidity lignite, an investigation on its drying behavior was carried out, using a method of Microwave Thermogravimetric Analysis (MTGA). The characteristic of heat and mass transfer during drying process was studied. The effects of initial lignite mass on its drying process and energy consumption were also addressed. In addition, changes of lignite pore structure, sulfur content, and calorific value were tested after drying experiment. The results indicated that lignite microwave drying was divided into three stages: incubation stage, high-efficient dehydration stage, and deep dehydration stage. It was in agreement with the variation of temperature inside the sample. High-efficient dehydration stage and deep dehydration stage were separated at a critical moisture content. Microwave power and initial mass could be properly matched, which was effective to increase dehydration rate and decrease energy consumption. It was further noted that the best power for achieving the least energy consumption was in advance to that for achieving the greatest dehydration rate, especially for initial mass of 20?g and 25?g. The optimum power for initial mass of 20?g and 25?g was found to be 385?W and 539?W, respectively. Pore structure of dried lignite was basically deteriorated. Meanwhile, lignite microwave drying at 231?W for 6?min could lead to an increase of calorific value by 8.1% and a decrease of sulfur content by 68.6%.