干化污泥型煤抗压强度的实验研究

利用微波干燥脱水污泥制备型煤粘结剂,与粉煤混合压制成型煤。通过正交试验考察成型压力、干化污泥含水率及添加比例对型煤抗压强度的影响。结果表明：微波干化的污泥型煤较粘土型煤的抗压强度大;成型压力、干化污泥含水率及添加比例均为型煤抗压强度的显著因素,各因素优化范围：成型压力为25～30MPa,干化污泥水分为40％左右,干化污泥添加比例为20％～30％。     

冶金炉窑用高强型煤黏结剂优配的实验研究

以湖南金竹山无烟煤为原料，采用正交实验法对冶金炉窑用型煤复合黏结剂各组分的配比及型煤成型的主要工艺参数进行了实验研究．结果表明，镁基黏结剂和成型压力对型煤的抗碎性能影响显著．型煤黏结剂各组分相对于原料煤粉的最优配比为：镁基黏结剂取4％，生物质纤维取1％，固化剂取0．6％，减水剂取0．12％．型煤成型的最佳工艺参数为：成型压力20kN，成型水分17％，烟煤掺量10%，煤料粒度组成：3mm～2mm颗粒为8％，2mm～1mm为12％，1mm～0．5mm为10％，0．5mm以下为70％．评估了该复合型煤黏结剂的成本，分析了其作用机理．     

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。     

Evaluation of biomass residue: 1. Briquetting waste paper and wheat straw mixtures

Studies have demonstrated that waste paper and wheat straw or their mixtures can be compressed to a relative density greater than unity, and stabilized at that density without binder material. A reduction in the volume of the material also provides a technological benefit, so the material could be transported and stored more economically than is possible at present. The effects of the briquetting pressure on the density, moisture content, and bending and compressive strengths of the briquettes were determined at six different pressures of 300, 400, 500, 600, 700 and 800 MPa. The optimum moisture contents and compressive strengths were found to be respectively 18.0% and 38.2 MPa for waste paper, 22.0% and 22.4 MPa for wheat straw, and 18.0% and 32.0 MPa for a 20.0% by weight of waste paper and straw mixture. The effect of the temperature and time on the briquette density of wheat straw was examined.     

粉煤成型机理研究进展

阐述了无黏结剂成型机理和粉煤有黏结剂冷压成型机理,说明无黏结剂成型机理主要包括沥青质假说、腐植酸假说、毛细管假说、胶体假说以及分子黏合假说;粉煤有黏结剂冷压成型时,黏结剂与粉煤的作用力主要有固体桥联联结力、静电吸引力、液体桥联联结力;两种机理均无法全面解释型煤成型机理和指导型煤生产实践。在此基础上,提出粉煤成型机理研究新方法,可从了解型煤微观结构入手,研究型煤硬度、弹性、塑性和表面物理化学性质等原煤自身性质以及粒度、水分、烘干温度和成型压力等工艺参数与不同黏结剂作用时型煤微观结构形态及变化规律,建立型煤制备过程/工艺-微观结构-宏观性质之间的关系来探寻粉煤成型机理。     

Factors affecting the strength of formed coke made from lignite char

Char made from narrow size fractions of lignite in a fluidized bed was briquetted at 140 MPa with various binder tars produced from the lignite. The raw briquettes were cured in air at 200 °C and then carbonized, usually at 925 °C. The tensile strength of the resulting formed coke could be as much as three times that of the best metallurgical coke, or as low as 2–3 MPa, depending on the type of binder used, or even a factor of ten lower than this if the curing stage was omitted. Curing is thus a crucial stage. Distinct optima of binder percentage and char particle size were found, giving maximum briquette strengths (≈ 13 MPa). A corresponding ‘strength surface’ suggested four factors associated with weakness of a briquette. Binders produced by air-blowing rather than nitrogen-blowing gave stronger briquettes. Fluidized bed tar was greatly ‘improved’ in this way, but Gray-King tar only slightly so, probably because the former contained more generally reactive species. Cured-only briquettes were usually surprisingly strong and carbonization increased this strength ≈ 1.5 times. Curing is considered to ‘fix’ the binder; carbonization changes the chemical nature of the ‘cement’ between the char surfaces but does not appreciably alter its spatial distribution. The carbonized briquette thus has substantially the same structural flaws as were present in the cured state and so has a strength closely correlated with that achieved merely by curing.     

粉煤成型及干燥工艺条件研究

考察了成型压力、原料粒度、粘结剂和外加水分等成型工艺条件对型煤抗压强度的影响,同时比较了两种干燥条件对其抗压强度的影响。结果表明：成型压力25 MPa,煤料破碎至〈3 mm,沥青加入2%,腐植酸钠添加5%,外加水为16%,并在100℃下干燥4 h所获得型煤的抗压强度最高,达到737 N/cm2。     

煤与牛粪生物质混合成型的研究

为了解决牛粪的利用问题,利用牛粪自有的木质素、纤维素、半纤维素等的黏结作用,将牛粪与煤经过中低压型煤成型机压制成型。研究了黏结剂与原料性质对生物质型煤强度的影响。结果表明:随着黏结剂添加量的增加,型煤强度逐渐增加,当黏结剂添加量超过10%时,型煤强度增加幅度逐渐变缓,黏结剂添加量不宜超过15%;随着无机黏结剂配比的增加,型煤强度先快速增大后缓慢降低,当黏结剂配比为5%有机黏结剂+6%无机黏结剂时,型煤强度最高;随着煤样粒度的减小,牛粪湿度的增加,型煤强度逐渐增加。最后分析了牛粪添加量对型煤燃烧性能的影响,说明生物质添加量越多,型煤初期燃烧速度越快,生物质添加量由20%增加到80%时,型煤燃烧速度变化不大。     

An Experimental Study on Binderless Briquetting of Low‐Rank Coals

The potential of binderless briquetting as a means of transforming low‐rank coals into low moisture high grade solid fuel products has been studied. Using two dried low‐rank coals, binderless briquettes with high mechanical strength have been successfully produced through mechanical compression. An increase in heating value was achieved as a result of moisture reduction in the briquettes compared to as‐received coals. The residue moisture content in the briquettes had a predominant effect on briquetting characteristics and there existed an optimum moisture content for the maximum briquettes strength. The chemical structure and wettability of binderless briquettes were analyzed using FTIR and contact angle measurement. The results showed that hydrophobicity and chemical structure significantly affected the briquette properties.     

型煤技术基础理论总结与探讨

总结了型煤技术基础理论中煤的粘结机理、几种成型假说;分析了成型过程从加料、加压、成型、压溃到反弹各阶段型煤的受力情况;并对影响成型的五个主要因素(煤料的成型特性,成型压力,煤料的水分,粒度及组成,粘结剂用量)进行了总结与探讨。     

The effect of different treatment conditions on biomass binder preparation for lignite briquette

The tests of treating rice straw with sodium hydroxide, lime and sulfuric acid were individually done and the possibility of using a binding agent based on rice straw as lignite briquette binder was studied. In this study, the lignite from Pingzhuang coal basin was selected as the coal for briquetting. It was found that the type of chemical agents and their concentration were the main factors influencing preparation of a binding agent based on rice straw. The binding mechanisms of a rice straw-based binder containing sodium hydroxide were quite different from that made with lime. The experiment showed that the rice straw treated with sulfuric acid could not be used as a briquette binding agent. Additionally, it made clear that comprehensive binders, which were prepared by adding bentonite, coal tar and/or polypropylene amide into rice straw-based binder, would have waterproof property and would benefit the quality of briquettes.     

影响泥炭土型煤机械强度因素分析

本文分析了孔隙率、含水量、制棒压强、加碱量等因素对泥炭土型煤机械强度的影响。     

Briquetting of Afşin-Elbistan Lignite

In this study, low-quality Afşin-Elbistan lignite was mixed with a high-quality Siberian bituminous coal and optimum briquetting conditions were investigated for blends with and without binder materials. The blends of lignite and bituminous coal were prepared to contain 30, 40, and 50% bituminous coal and briquetted under pressures of 566 MPa and 708 MPa. The blends of lignite and bituminous coal were also briquetted using sunflower shell, sawdust and molasses as additives. In these experiments, the percentage of the lignite in the blends was fixed at 50%, so that the sum of the percentages of the bituminous coal and binder additive was always 50%. In this way, the low-grade lignite and high-quality bituminous coal dust are converted into a compact and stable fuel which has a higher quality.     

NaOH改性生物质做为型煤粘结剂的成型研究

探讨了NaOH溶液改性生物质秸秆作为型煤粘结剂的可行性。实验研究了NaOH溶液浓度以及生物质种类对型煤机械强度的影响,并采用显微镜、SEN和能谱分析了生物质型煤的成型机理。微观结构分析表明改性生物质具有粘结作用;碱液浓度与纤维的降解程度成正比;生物质纤维的降解程度直接影响其制得型煤的机械强度。结果表明,1％NaOH溶液改性的稻草秸秆具有较好的粘结性,所制备的型煤机械强度较好。     

Physicochemical properties of fuel shales

Current economic conditions call for innovative products such as coke for the electrode industry, graphite, and fullerenes. To that end, the physicochemical properties of fuel shales must be determined. Attention focuses on shales from the Pribaltiisk Basin (Leningrad field). The goals of the experiment are to determine the physical properties of the shales (moisture content, ash content, actual and apparent density, porosity), the optimal briquetting conditions, and the calorific value of the briquets. The influence of the fractional composition and moisture content on briquet strength is studied. The influence of the heating conditions on the physicochemical properties in the shales is considered. The briquets are heated in pipe furnaces with uncontrolled and controlled atmospheres, in the temperature range 200–1000°C. It is found that the increasing the briquetting pressure (from 10 to 15 MPa) and moisture content (from 11.6 to 37%) improves the briquet strength, while adding coal fines (4 wt %) and reducing the moisture content (to 23%) improves the calorific value of the briquets. Semicoking begins at 400°C. Further heating increases the yield of gases and reduces the yield of semicoke. After pressing, the shale fines may expediently be processed by heat treatment to obtain a graphite material.     

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。     

Densification of water hyacinth — basic data

The briquette-forming ability of water hyacinth (WH), a plant with prolific growth, to produce a fuel wood substitute or for further processing has been investigated. Compared to straw and sawdust, WH can undergo binderless briquetting. Pressure, water content and temperature have a strong influence on the briquette-forming ability of WH. Laboratory trials showed that optimal conditions are achieved between compaction pressures of 80 and 200 MPa, temperatures between 70 and 80 °C and water contents between 8 and 12 wt%. Die ram-extrusion and pellet-mill briquetting presses allow the compaction of WH with acceptable throughputs and with a specific energy consumption of 180 MJ t^?1. The produced briquettes, with a density of 1400kg m^?3 and a compression rate of 1:14, proved to be abrasive-resistant and showed an acceptable compressive strength. The re-expansion behaviour of the briquettes was moderate. The extractable matter of WH does not contribute to the briquette strength. No experimental indication of lignin softening could be found.     

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。     

活化污泥基黏结剂制备型煤型焦试验研究

为实现粉煤的综合利用,以城市污泥为黏结剂的基础组分,采用化学方法活化,利用粉煤成型技术制备型煤,对工艺条件进行研究,考查了成型压力、污泥含量、干燥时间对型煤冷压强度和湿压强度的影响,确定了最佳工艺条件。结果表明,污泥含量为12%、成型压力12 MPa、干燥时间8 h时,制得型煤的冷压强度为1 522.5 N,落下强度为97.7%,型煤600℃干馏2 h制得型焦的强度、灰分、挥发分、发热量等主要指标均达到《陕西省地方洁净型煤技术标准》。利用活化污泥可制备出适用于工业生产的洁净型煤。