水煤浆制浆技术的研究进展

制取性能稳定的水浆是水煤浆燃料技术开发的关键，介绍了国内外在水煤浆制浆用添加剂、粒度分布和制浆工艺方面的研究进展，并就目前水煤浆制浆技术存在的问题和发展趋势进行了探讨。     

矿物质在煤粉中的分布规律

对不同粒度煤粉中的矿物质分布特征研究表明,矿物质含量随煤粉粒度的增大而增多,单体矿物颗粒含量则正好相反,这一关系可以用mi=k(di)^D-D1来描述,其中,D为煤粉的粒度分布分形维数,D1为煤粉中矿物质的粒度分布分形维数。这一关系式表明,可以根据煤粉及矿物质的粒度分布特征预计不同粒度煤粉中的矿物质含量。     

不同煤化程度煤的可磨性指数变化和破碎特性

可磨性是煤加工利用过程中的一个重要指标，可磨性指数与煤的破碎机理、煤粒破碎后的粒度分布均有关系。运用哈氏可磨性指数测定仪和马尔文激光粒度仪对几种不同煤化程度的单煤进行了可磨性指数测定和激光粒度分析试验，分析了煤种的破碎过程以及破碎后的粒度分布规律。试验结果表明，经过哈氏可磨性测定仪后，各煤种的工业分析都发生了不同程度的变化，而煤粉破碎后的粒度分布取决于煤种的煤化程度，而与煤种的可磨性指数相关性较小。     

水能使煤成为更好的燃料

固体的煤不是很有吸引力的燃料。把煤磨成颗粒直径小于250微米的粉末状,然后再与水混合使用,这样煤的不受欢迎的形象就改变了。虽然把煤粒悬浮在某种液体内作为燃料的这种概纪并不是新的,但是用水和煤混合来燃烧的想法只是大约在7年以前才开始的。现在科学家们正积极热情地研究水煤浆来代替石油,水煤浆将在发电站,工业锅炉,高炉甚至在汽车的发动机中燃烧。     

水煤浆水分对锅炉燃烧的影响

在水煤浆和原煤的燃料特性对比的基础上,分析了水煤浆中水分对着火燃烧的影响、烟气中水蒸气的来源及水蒸气对传热的影响,可得出结论:在保证水煤浆粘度和粒度的前提下,应该尽量使用高浓度水煤浆.     

乙醇/柴油混合燃料喷雾粒度分布特性研究

采用激光粒度分析仪对乙醇/柴油混合燃料稳态自由喷雾粒度分布进行了试验研究,并就不同喷油压力、喷孔直径对乙醇、柴油及乙醇/柴油混合燃料稳态自由喷雾粒度分布的影响进行了对比研究。试验结果表明:各种燃料喷雾索特平均直径(SMD)的空间分布沿喷雾轴线均呈逐渐减小的趋势,其中柴油喷雾的SMD在20～40μm范围内变化,乙醇喷雾较柴油喷雾具有更小的SMD,且其空间分布较为均匀;随着乙醇含量的增加,乙醇/柴油混合燃料喷雾的SMD不断减小,其SMD大小和空间分布均匀性介于柴油喷雾和乙醇喷雾之间。     

生物柴油燃料对柴油机不同负荷工况微粒粒度分布的影响

利用TS13090 EEPS微粒粒度测试系统,试验研究了生物柴油、石化柴油燃料微粒稳态工况下的粒度分布特征.研究结果表明,高压共轨柴油机微粒排放粒径绝大部分在300 nm以下,生物柴油、石化柴油燃料微粒粒度分布均呈双峰结构,核态蜂值区域在10 nm附近,积聚态峰值区域在60 nm附近.生物柴油燃料微粒排放以小粒径核态微...     

60T/H 燃油工业锅炉应用水煤浆工业性试验

前言水煤浆是七十年代发展起来的新型低污染液体代油燃料,这种新型燃料的出现得到了美国、日本、瑞典、意大利、加拿大、苏联等许多国家的重视,纷纷开展了基础研究和工业性试验,先后在工业锅炉、电站锅炉、炼铁高炉和加热炉上取得了成功,并已达到了商业应用的水平。水煤浆成为一种新型的常规燃料品种,改变了煤炭的运输方式和电厂的燃料供应系统,使水煤浆应用前景更为宽阔。1988年“水煤浆制备与燃烧技术”列为“七、五”攻关项目,北京造纸一厂50T/H 燃油锅炉应用水煤浆代油燃烧技术以及水煤浆工业性示范试验,在华煤水煤浆技术联合中心的组织下,在攻关组全体同志的努力下,设计安     

浮选尾煤制备水煤浆及制浆工艺

通过对浮选尾煤水煤浆流变特性的研究及制浆工艺的探讨，得出了浮选尾煤是制备水煤浆的理想原料并具有广泛应用前景的结论。     

我国研制出高浓度水煤浆添加剂

高浓度水煤浆是近20年发展起来的一种煤基流体燃料，将具有一定粒径分布的煤粉均匀分布在水中形成高度分散的煤水混合物。通过泵送、雾化后可以稳定地燃烧，也可以管道输送，并长期贮存。水煤浆在取代油、气及干煤燃烧方面具有环保、节能等综合效益。     

浅议水煤浆锅炉的技术特点及其应用

本文从节约能源、减少污染物排放的角度出发,阐述说明水煤浆锅炉在节能环保方面的优越性。文章详细介绍了水煤浆燃料的特点;结合工程实例着重说明水煤浆锅炉燃烧系统、除尘、除硫、烟气排放的工艺流程;水煤浆锅炉在燃料消耗、污染物排放2方面与燃煤锅炉的技术经济比较分析,以及水煤浆锅炉的环保效益。     

35t/h流化悬浮燃烧水煤浆锅炉的设计与应用

水煤浆作为煤炭深加工的产品,是一种低污染、高效能的新型洁净燃料。针对水煤浆的燃料特点,分析了当前水煤浆锅炉设计与运行中存在的问题,并以35 t/h锅炉为例,着重介绍了流化悬浮燃烧水煤浆锅炉的结构特点及其技术优势,详细分析了流化悬浮燃烧锅炉如何解决水煤浆在小空间燃烧易结焦、燃烧不稳定这一难题,从而真正实现了水煤浆的低温、高效洁净燃烧,对工业锅炉洁净煤技术的发展将产生深远的影响。     

2_8MW热水链条锅炉改烧水煤浆燃烧试验分析

水煤浆是新型洁净燃料,有着很好的应用前景。在山东新汶矿业集团中心医院2．8MW热水锅炉改烧水煤浆的工业应用中,锅炉燃烧稳定,燃烧效率高,低负荷稳燃能力良好。本文对水煤浆在炉内燃烧过程,火焰中心,火炬长度,结渣特性等进行了分析。     

竖直弯管内水煤浆局部阻力特性的研究

在中试试验台上对水煤浆流经竖直弯管的局部阻力特性进行了研究,分析了水煤浆在竖直弯管内流动的最佳弯径比,并利用多种阻力特性分析方法对试验结果进行了处理.结果表明:水煤浆流经竖直弯管时存在最佳弯径比;竖直弯管内的流动有效长度和摩擦阻力损失比存在较明显的变化趋势,且受弯径比影响较大;利用经验公式对竖直弯管内的局部阻力损失系数与雷诺数的关系进行拟合,尽管存在弯径比的影响,但拟合误差较小,能满足工程实际应用;将De改进为De′,对摩擦阻力损失与De′的关系进行拟合,可以很好地消除弯径比的影响,得出拟合误差更小、能更好地指导工程实际应用的经验公式.     

Characterization and performance analysis of silicon carbide electrolyte matrix of phosphoric acid fuel cell prepared by ball-milling method

The effect of ball milling in making a silicon carbide slurry for the electrolyte matrix of a phosphoric acid fuel cell (PAFC) was studied by measuring the zeta potential and the particle-size distribution, and by analyzing cell performance. The ball-milled slurry gives a better particle distribution than the conventional mechanical-stirring method, and the particle distribution of the slurry depends on balling time and pH, which is confirmed by zeta potential. A single cell with a ball-milled electrolyte matrix also displays high performance. It is concluded that the ball-milling method is preferable to the mechanical-stirring procedure for preparing silicon carbide slurries.     

The effect of sludge from coal to oil process on the stability of coal/sludge water slurries

Sludge produced from coal to oil process contains larger content of tar, phenols, ammonia components, and ashes. It cannot be treated by using traditional disposal methods as landfill or incineration. A promising solution is to blend sludge with coal for preparation of sludge/coal-water slurries. The new slurry fuels could be used in commercial gasifiers for syngas generation. In this process, the first goal is to form a stable slurry. In the research project, the addition of sludge on the stability of coal-water slurries was investigated. Results show that the addition of sludge can improve the static stability for slurries prepared by lean coal, coking coal, and lignite. The effect on stability of coking coal-water slurry is the most significant. The proportion of sludge to lean coal added in the slurry can be maintained at 10% to 15%.     

Hydrothermal preparation of low-rank coal-water fuel slurries

Lignite and sub-bituminous coals are by nature high in inherent moisture and oxygen content and low in calorific heating value. As-mined low-rank coals when mixed with water generally produce slurries with low solids content and with heating values generally less than 11.6 MJ/kg. These same slurries are usually unstable and form hard-pack sediments quickly, unless chemical additives or constant agitation are added. The low heating value and poor storage and flow characteristics of these coal-water mixtures discourage the use of raw lignite and subbituminous coals for preparation of slurries for fuel purposes.Hydrothermal conditioning, in a water slurry at temperatures above 230 °C and pressures above 552 MPa, is one method that can significantly aid in the preparation of low-rank coal-water fuels. High-pressure hot-water thermal conditioning of lignites and sub-bituminous coals has been found not only to change both the chemical and physical characteristics of the coal but also to alter the coal slurry's rheological properties. These changes are controlled by process variables (i.e. temperature, residence time, particle size, and mode of processing) and result because of decarboxylation, mild pyrolysis, extraction, dehydration, and surface modification; all of which occur during hydrothermal treatment. Using the hydrothermal process, concentrated low-rank coal-water slurries with heating values approaching or exceeding the heating value of the as-mined coal have been achieved with pseudoplastic flow behavior and stability towards settling, without the use of additives.Pilot-scale studies using a 90-kg/hr process development unit (PDU) are currently under way to produce hydrothermally treated low-rank coal fuel slurries for combustion tests in a pilot-scale, slurry-fed test furnace.     

A comparison of coal-water slurry pipeline systems

Coal-water slurry pipeline systems are in various stages of development and exhibit many similarities, but they also have several unique characteristics. Existing and proposed systems range from conventional coarse- and fine-coal slurry pipeline media to the stabilized flow and coal-water mixture slurries that are under development. The roles planned for the coal being burned and the coal slurry pipeline, combined with the advantages and disadvantages of the alternative systems, tend to determine which system is most applicable for a particular use. Principal selection criteria include transport distance, water requirements, cost, and end use. Conventional coarse-coal slurries are best suited to very short-distance applications, where low water use is possible through closed-loop operation. Conventional fine-coal slurries generally require greater preparation and dewatering costs but can be transported great distances. These two systems offer excellent opportunities for rapid implementation because they have been tested on a full-scale basis. Use of the stabilized-flow system offers opportunities for domestic combustion and export because it is cheaper than coal-water mixtures. Coal-water mixtures provide the unique capability to displace oil use in oil-fired boilers. The coal-water pipeline systems for stabilized-flow and coal-water mixtures have not yet been tested on a large-scale basis.     

新建670 t/h超高压水煤浆锅炉的设计与调试

南海发电一厂新建的超高压670t/h水煤浆锅炉在国内属首创产品.为了对锅炉的设计、制造及安装质量进行检验,并为制定运行规程及今后同类型水煤浆锅炉和配套工程的设计提供试验依据,进行了燃烧调整试验.结果证明锅炉燃料适应性能好,烧油、烧浆和油浆混烧均能满足设计要求,全烧浆时燃烧效率在99.6%以上.它的成功投运具有显著的经济和社会效益.图5表3参4     

粒度级配、添加剂种类对宁东煤成浆性影响的实验研究

总结了宁东煤的特点,认为期内水质量分数高,难以制备高质量分数的水煤浆。通过实验,研究了添加剂种类、煤粉级配对低变质宁东煤成浆性的影响。结果表明,采用双峰级配可配制高性能的水煤浆。