两种褐煤无粘结剂成型特性的对比研究

实验研究了呼伦贝尔褐煤和印尼褐煤的成型特性,分析了成型压强、粒径配比、水分、氧化、褐煤煤种等因素对型煤强度的影响,型煤强度随成型压强的增大而增大,不同煤种最佳粒径配比不同,最佳水分范围为12%¹5%,氧化煤制型煤的强度高于原煤。     

2种改善型煤种的配煤炼焦试验研究

对柳林高硫焦煤和俄罗斯肥煤2种改善型煤种煤质进行分析,并分别对比同类常用炼焦煤,结果表明,柳林高硫焦煤和俄罗斯肥煤均为单一煤种,属于优质炼焦煤,具有较高的G值、Y值,可以作为配煤炼焦的基础煤种。20 kg小焦炉炼焦试验结果表明,2种改善型煤种单种煤所得焦炭质量较好,与其他煤种均有较好的配伍性。工业单独配用后焦炭质量的对比表明,2种改善型煤种可改善焦炭质量,降低企业配煤成本。     

循环流化床锅炉灰渣中残碳高原因分析及预防

0前言 河南金大地化工有限责任公司（以下简称金大地公司）的循环流化床（CFB）锅炉产生的高压蒸汽供汽轮机发电后,全部进入公司0．4MPa和3．5MPa蒸汽管网,供化工系统生产使用。锅炉设计煤种为平顶山烟煤,实际主要为平顶山烟煤和合成氨造气炉渣混烧,锅炉灰渣残碳量基本能够达到设计值。期间,由于煤种由平顶山烟煤改为洛阳无烟煤,使炉渣中残碳量由原2％（质量分数,下同）上升到5％～7％,飞灰残碳量由原6％上升到15％～20％。为此,结合实际运行工况,分析灰渣中残碳量过高的原因,提出了合理控制与调整燃烧的办法,降低了灰渣中的残碳含量。     

劣质煤+石灰石在水煤浆气化中的应用探索

分析了Texaco煤气化工艺对煤种的适应性选择,介绍了陕西神木化学工业有限公司气化系统使用劣质煤加石灰石的试烧情况。结果表明,汇森煤(劣质煤)添加少量石灰石(1%左右)可以满足公司Texaco水煤浆气化用煤的要求,在为公司带来一定效益的同时,也可为其他采用水煤浆气化工艺的企业提供一些参考。     

配合煤塑性体流动性与其黏结指数的关联性研究

对炼焦煤黏结指数(G)和基氏流动度等指标进行分析测定,研究配合煤G值和基氏流动度特征指标的变化规律.结果 表明,相同煤种间配合煤的G值和最大流动度具有良好的加和性,不同煤种间加和性差;增加低流动度煤种的配入比例,会导致配合煤软化温度升高,软固区间变窄;配合煤样的G值与lgMF呈线性关系和二次曲线关系的加成.     

食谱化配煤在煤化工企业的应用探索

通过对各产地煤种在鲁奇气化炉上的运行分析,探索多煤种混和在鲁奇气化炉上使用的配比原则,分析了不同负荷结构、不同产地煤种的配煤要求,制定不同配比模式下气化炉的操作调整手册,最终达到多煤种混和条件下的气化炉的安全稳定和经济运行,拓宽气化炉的原料煤源,减轻采购压力。     

全无烟煤煅烧的生产实践与体会

<正>我公司2 500t/d生产线一直使用烟煤煅烧,由于地处海拔1 982m的云南西部滇缅边境腾冲县,交通道路崎岖曲折,给原燃材料运输带来不便,致使北方优质烟煤的到厂价格较高。云南境内无烟煤储量丰富,与烟煤的发热量相差不多,并时有价格差异,同时厂区周边还蕴藏废弃不用的褐煤。为节约成本,我公司开展了不同煤种混烧及全无烟煤煅烧的生产实践。1不同煤种的混烧实践2013年10~11月曾尝试烟煤+无烟煤煅烧,生产     

用于混煤燃烧控制砷排放模型研究

混煤掺烧是控制燃煤砷排放的有效方式,但由于缺乏相关的配煤模型,限制了该技术的应用。根据燃煤过程中砷的挥发释放机制,提出一种采用砷的释放指数P表征煤燃烧过程砷的释放特性的配煤模型。该模型综合考虑煤的灰分、灰中主要矿物元素含量、各矿物元素对砷的固定系数以及煤中砷含量等因素。研究结果表明,随着煤灰固定系数由23.12增至50.90,煤灰的气相砷吸附量由3.39 mg/g增至6.14 mg/g;随着释放指数P增大,砷的固定率减小,且随着温度升高,两者相关性由900℃的0.67增至1 300℃的0.86。根据P值筛选煤种进行掺烧,当掺混煤种P值差异较大时,掺烧低P值煤种不仅可降低混煤中的砷含量,还能促进高P值煤的砷在灰中富集,促进率达77.14%;掺混煤种P值差异较小时,掺烧低P值煤种会促进砷的释放。本模型可较好地筛选煤种,为混煤掺烧控制砷等痕量元素的排放提供了新的思路。     

恩德粉煤气化炉灰渣再利用分析

恩德粉煤气化炉采用循环流化床气化技术制气，为了避免结渣，流化床底部在900～950℃条件下进行氧化和气化，在这种条件下，要求原煤的活性和灰熔点高，褐煤和长焰煤是最合适的原料。我公司恩德粉煤气化炉设计时是以内蒙免渡河长焰煤为原煤，设计灰分含量15．59％，但由于铁路运输及设计煤种煤矿储藏和开采能力等影响，现实际使用的原煤大多为内蒙古褐煤，煤质较差，灰含量高达30％～50％，     

电化学氧化煤浆特性研究

采用伏安法对六种煤浆的电解氧化特性进行研究,考察了煤种、铁离子溶液催化剂、温度和搅拌速度对氧化电流密度的影响。结果表明,温度、电压和转速的增加可以提高其氧化电流密度,在室温下加入5 mmol Fe3+,可以使神木煤浆的氧化电流密度提高至18.4 m A/cm2。通过XRD分析可知,电解破坏煤的大分子结构。     

炼焦精煤氧化性质的研究

测试了5种露天堆放的炼焦煤在不同时间的各指标变化情况,结果表明：高挥发分高粘结性的炼焦煤在氧化初期结焦性略有上升,然后逐步下降;中等及低挥发分的炼焦煤随着煤质的氧化其结焦性越来越差;煤的挥发分随堆放时间延长而下降,灰分则略有上升。     

Effect of oxidation on the chemical nature and distribution of low-temperature pyrolysis products from bituminous coal

Two bituminous coals, a high volatile Eastern Canadian and a medium volatile Western Canadian, were used to investigate the effect of oxidation on yields and chemical composition of gases, liquids and chars produced during coal pyrolysis. Pyrolysis experiments were performed at 500 °C using the Fischer assay method. Mild oxidation of coals resulted in a decrease of liquid hydrocarbon yields. Further coal oxidation increased the proportion of aromatic carbon in liquid products as determined by n.m.r., and also increased the content of oxygen in liquid products. The content of oxygen in chars was markedly lower than in corresponding coals. An attempt is made to explain reactions occurring during oxidation and subsequent pyrolysis of coal on the basis of differences in chemical composition of gases, liquids and chars.     

Influence of coal forced oxidation on technological properties of cokes produced at laboratory scale

The effect of coal oxidation in air at 140 °C on the technological properties of cokes obtained at laboratory scale from two medium volatile bituminous coals has been studied. The proximate and ultimate analyses do not show important changes with coal oxidation time. However oxidation clearly has a strong effect on the plastic properties of the coals in view of the fact that the Gieseler fluidity eventually disappears. From this point variations in plastic properties can still be detected by FSI. Other changes, such as a shortening of the length of the saturated fragments of the aliphatic chains, a decrease in the aliphatic hydrogen content and an increase in the oxygen-containing groups are detected by PA-FTIR. It was also found that the main coke quality indices (mechanical strength and reactivity to CO₂) of both coke series are impaired with coal oxidation. A close relationship between reactivity to CO₂ and the micropore specific surface area of the cokes has been corroborated.     

煤的溶胀处理对药用腐植酸提取的影响研究

以气煤、肥煤、焦煤、瘦煤为样煤,进行了样煤的粉碎、有机溶剂溶胀和硝酸氧化处理,考察了处理后煤样中的药用腐植酸得率。结果表明,吡啶和N,N-二甲基吡咯烷酮是溶胀较好的溶剂;样煤粉碎后,随着粒度的减小,煤的溶胀率增加;粒度粉碎至200目的气、肥煤经吡啶溶胀和硝酸氧化后,煤样的药用腐植酸得率可达到73.0%和71.4%,而经甲醇溶胀和硝酸氧化的200目气煤药用腐植酸得率为56.4%和58.4%。实验结果表明,煤样经过溶胀和硝酸氧化处理,对药用腐植酸的提取有促进作用。     

Influence of coal forced oxidation on technological properties of cokes produced at laboratory scale

The effect of coal oxidation in air at 140 °C on the technological properties of cokes obtained at laboratory scale from two medium volatile bituminous coals has been studied. The proximate and ultimate analyses do not show important changes with coal oxidation time. However oxidation clearly has a strong effect on the plastic properties of the coals in view of the fact that the Gieseler fluidity eventually disappears. From this point variations in plastic properties can still be detected by FSI. Other changes, such as a shortening of the length of the saturated fragments of the aliphatic chains, a decrease in the aliphatic hydrogen content and an increase in the oxygen-containing groups are detected by PA-FTIR. It was also found that the main coke quality indices (mechanical strength and reactivity to CO₂) of both coke series are impaired with coal oxidation. A close relationship between reactivity to CO₂ and the micropore specific surface area of the cokes has been corroborated.     

Investigation of an iron-based additive on coal pyrolysis and char oxidation at high heating rates

Iron-based catalysts have been shown to enhance coal pyrolysis and char oxidation at low to moderate temperatures and heating rates (< 1250 K and 1–1000 K/s). Such catalytic activity has not been demonstrated at high heating rates and temperatures approaching pulverized coal combustion applications. The effect of an iron-based additive on coal pyrolysis and char combustion was studied in a flat-flame burner system at high particle heating rates using a Kentucky bituminous coal. Pyrolysis and char reactivity of two treated coals with different catalyst loadings were studied and compared with the untreated coal. The total volatiles yield for the treated coals increased between 14 and 18% (absolute) on a dry ash-free basis compared to the untreated coal in experiments conducted at 1300 K. A first-order char oxidation model was used to compare the apparent char reactivities of the treated and untreated coals measured at 1500 and 1700 K. An increase in apparent char reactivity was observed for both treated samples.     

Diffuse reflectance infrared spectrometry of powdered coals

Diffuse reflectance Fourier Transform infrared spectrometry has been shown to allow spectra of powdered coal samples to be measured at high sensitivity. Quantitative precision is good, so that the rank of individual coals and the composition of coal blends can be determined in <15 min. The degree of oxidation of coals, both for natural oxidation in the seam and for laboratory oxidation, can be determined from diffuse reflectance spectra of coals and from the second derivative of these spectra. Second-derivative spectra allow quantitative estimates of oxidation to be obtained without the application of spectral subtraction routines, which require standard reference samples that are not always available. The potential for using diffuse reflectance infrared spectrometry for monitoring reactions of powdered coals in-situ has been demonstrated.     

Electrochemical oxidation of coals: Voltammetry and mass spectrometry

The anodic oxidation of sulphuric acid slurries of lignite, bituminous, and anthracite coals; a high-yield extract of coal; and carbon black, has been investigated voltammetrically and with simultaneous m.s. monitoring of evolved gases. The previously reported evolution of carbon dioxide at very low voltages was shown to be chemically released from minerals. The low rank coals and the asphaltite did show considerable electrochemical activity near to 1.0–1.2 V, mainly from the conversion of leached ferrous ion to the ferric form. Further activity near 1.4–1.5 V arose from the oxidation to CO₂ of leached organic matter. For well-washed low rank coals, the coal extract and the anthracite, CO₂ release was only observed at high (>2.8V) anode voltages, with simultaneous release of oxygen. Electrochemical gasification of coal via anodic oxidation of macromolecules at low voltages did not occur.     

Dry beneficiation of Slovakian coal

The dry beneficiation of three types of Slovakian brown coal, namely Ci'gel, Handlova', and Nova'ky coal was conducted via triboelectrostatic separation. Three different types of separators—parallel plate, cylindrical and louvered plate—were used for this study. It was found that a parallel plate separator could reduce the ash contents of Ci'gel and Handlova' coals. The poor quality of separation for the Nova'ky coal studied is probably due to the particle–particle interactions and surface oxidation states of the coal.     

Low-temperature oxidation of single and blended coals

The oxidation of different types of coal under self-heating conditions is considered using the crossing point method performed in a cubical wire-mesh basket. This study investigates the effect of particle size and the physical structure of coals (including pore size and surface area) on the self-heating character of high and low rank Indonesian coals and their blends. The results confirm that both particle size and surface area give considerably different effects on critical ambient temperature, the activation energy and the product of exothermicity and the pre-exponential factor of low and high rank coals. It was found that the self-heating characteristics of high rank coals were strongly dependent upon the particle size of the coals. For low rank coals, the dependence was weaker. A coal bed with mixed sizes is thus more vulnerable than one with segregated sizes. This means that one must carefully consider the particle size distribution to judge the spontaneous ignition behaviour of coal. It is suggested that the potential for spontaneous combustion of blended coal is greater following the increased percentage of more reactive coal.