Vibroacoustical selective agglomeration of coal slimes

Coal slimes from coking coal with an average ash content of about 45% and difficult separation characteristics have been studied. Investigations have also been carried out on two artificial mixtures of gangue and coal of low ash content. Two kinds of agitation have been tested: mechanical—rotational (with an impeller mixer) and vibroacoustical (with vibrating band) at a frequency of 50 Hz and an amplitude of 1 – 2 mm. Vibroacoustical agitation was much more efficient than mechanical-rotational. Second-degree orthogonal-central-compositional planning was used for studying slimes of appropriate size (−0.063 mm). In the most successful test with natural slimes, an efficiency of separation of 34.41% was obtained with the following technological parameters: yield of concentrate 27.93%, ash content of concentrate 22.00%, yield of refuse 72.07%, ash content of refuse 54.30%, the ash content of the run-of-mine coal being 45.28%. These results are close to the best ones obtained with the same slimes by fractional analysis in a liquid of density 1500 kg/m³. In this case, an efficiency of separation of 39.18% was obtained with yield of concentrate 35.04%, ash content of concentrate 24.01%, yield of refuse 64.96%, and ash content of refuse 56.01%.

The experiments on selective agglomeration have been carried out using kerosene at 14.8% consumption with respect to solids. The investigations are of a preliminary character.     

Determination of total fluorine in coal by the combustion-hydrolysis/fluoride-ion selective electrode method

A rapid analytical method has been developed for the determination of fluorine in coal. Coal is mixed with quartz sand, then burnt and hydrolysed in steam and oxygen at 1100 °C, whereupon the different forms of fluoride in coal become solubilized. The fluorine is determined with a fluoride-ion selective electrode. The method proposed is not affected by the ash content of the coal. The obtained solution has a simple ion composition and a low blank value giving the method potential as a fluorine determination technique. A series of typical coals have been tested and the agreement between the proposed method and the ASTM method and alkali-fusion method is satisfactory. Two sedimentary rock standards have been analysed and the results are within permissible limits of error. The method is considered to be accurate and reliable, and is first compared with the half-fusion method.     

煤的适应性对水煤浆加压气化工艺的影响

从煤的适应性角度分析原料煤的发热量、原料煤的灰分含量及灰熔点、原料煤的元素组成、煤浆浓度和煤粉粒度分布以及煤的挥发分对水煤浆加压气化工艺的影响。通过国家一级标准水煤浆与以原料煤制成的水煤浆特性的对比,表明红柳林煤矿的烟煤是合适的水煤浆加压气化工艺用煤。     

Identification of clay minerals in coal by selective cation saturation

The accurate identification of clay minerals in coal is important because of their high relative abudance and because they give an indication of the environment of coal deposition. In addition, there is evidence that clay minerals may act catalytically in several coal liquefaction processes. Current methods used for identification of clay minerals in coal are shown to be subject to errors because the method of separation of the clay fraction leaves the clay partially or totally saturated with sodium. The sodium-saturated clay makes identification of smectite, vermiculite, and interstratified clay minerals very difficult, especially where one or more co-exist in the clay fraction. A method based upon selective cation saturation with potassium and magnesium is shown to allow identification of several additional clay species in the low-temperature ash of coal not detectable using the sodium-saturated clay.     

The enrichment of fine particles of coal by aggregation part II. The use of the selective aggreagation method

Tests on aggregation enrichement of fine particles of coal are presented. The selective aggregation process, named ‘shear flocculation’ by Warren [7, 8], was conducted in a cylindrical beaker. The aggregation of the coal grains results from the action of shear forces while the feed is mixing with the collector (diesel oil). The aggregates formed were then separated from gangue by aeration in a flotation machine. This allows for almost complete recovery of coal. Preliminary aggregation of coal grains made it possible to eliminate the frothing agents usually needed in such a process.     

Associations and parageneses of microelements in coal

Microelements present in coal may be chemically bound with organic matter or with mineral impurities (clastic and authigenic minerals). Analytical data present the total (gross) content of microelements in coal. Such microelements are generally present in associations. In addition, some chemical elements accumulate in the coal on account of their content in organic matter; they constitute a paragenesis. In predicting the content of rare metals in coal deposits and in their extraction from the coal, it is important to establish the parageneses of the microelements—in other words, to distinguish the parageneses from associations of microelements. Such microelements may create anomalous concentrations in the coal. The present work establishes the characteristics of associations and parageneses of microelements in coal and proposes a statistical method for distinguishing parageneses from associations. The method is illustrated for data regarding Baikal coal deposits; it proves very effective.     

FCSMC-3000旋流—静态微泡浮选柱运行实践

兴华焦化厂采用静态微泡浮选柱技术回收煤泥中的精煤,当入料矿浆浓度为８０ｇ／Ｌ,灰分为１１％～１４％时,精煤回收率可达８０％,精煤灰分稳定在６％左右;回收的精煤掺入炼焦精煤中,生产的焦炭仍能达到出口焦炭质量标准。     

Solid/solid separation by selective agglomeration with agglomerant recovery by thermal desorption

In this study, selective agglomeration is used as a simple physical technique to reduce the ash content of coal tailings, in order to reduce environmental pollution and to increase the value of these materials for combustion and energy recovery. A pilot plant based upon this separation method was constructed, permitting the de-ashing of the tailings to a high level and the recycling of the agglomerant used for these operations by thermal desorption from the agglomerates. The effects of many operating variables have been examined for two different tailings and the efficiency of the process for cleaning tailings and agglomerant recovery has been demonstrated. Moreover, a tailings de-ashing efficiency of 90% was achieved for this process, and a recovery and re-cycling efficiency for the agglomerant of 82% was also realised.     

补气料仓中宽筛分粒煤的下料特性

在自行设计的有机玻璃补气料仓系统上对宽筛分粒煤下料特性进行了实验研究,结果表明,料仓出口直径、粒煤粒径和外水分对宽筛分粒煤在补气料仓中的下料特性有显著影响.宽筛分粒煤的下料流率随料仓出口直径的增大而增加,但增加量随着补气量的增加而减小.增加宽筛分粒煤的平均粒径使料仓出口有效尺寸减小,导致物料下料流率减小.增加宽筛分粒煤...     

Evaluation of gas content of coalbed methane reservoirs with the aid of geophysical logging technology

The geophysical logging technology has been employed in connection with field and laboratory tests for coal reservoir evaluation in Huainan and Huaibei coalfields, China. The relationships between coalbed gas content of coal reservoir and characteristics of geophysical logs have been investigated by means of the combined analyses of experimental and geophysical logging data. Coalbed gas content of drilling core samples from coal seams was determined experimentally. The results, together with the log data obtained from geophysical logging technology, have been analyzed by using geological statistics, permitting correlation of the coalbed gas content to the log responses. The correlation developed in this study provides better understanding of the coal reservoir for coalbed methane exploration in given coalfields by an improved prediction of the coalbed gas content.     

Optimal preparation of oxidized coal

The oxidation index is an important characteristic of coal and coal batch, indicating the change in coking properties on oxidation. The coke obtained from coal batch containing poorly clinkering oxidized coal has a higher content of isotropic carbon and a lower content of anisotropic carbon. That explains its increased reactivity and impaired mechanical and postreactive strength. The oxidation on storage is greatest for small coal classes (<0.5 mm). Preliminary removal of <0.5 mm oxidized coal markedly improves the reactivity and also the mechanical and postreactive strength. A method of preparing oxidized coal for coking is proposed: finer grinding (until the content of the ≤1 mm class is 100%). That considerably reduces the influence of the oxidized coal on the quality of the coke produced.     

担水沟煤矿瓦斯地质规律研究

为了加深对煤矿瓦斯地质规律的研究,通过收集、整理担水沟煤矿大量的瓦斯地质资料,分析研究了影响井田煤层瓦斯赋存的主要地质因素,阐述了煤层瓦斯赋存特征及分布规律,研究表明：井田整体上瓦斯含量较小,煤层瓦斯含量具有随煤层埋藏深度增加而增大的趋势。     

平顶山高灰熔融性温度煤的气化反应性研究

介绍了平顶山地区有代表性的7种煤样在800℃～1 200℃下,其脱灰煤焦-CO2气化反应活性的实验,主要考察了煤种、灰含量及粒径对煤焦反应性的影响,实验结果表明:煤种对煤焦-CO2气化反应有明显影响;煤中灰分对煤焦气化反应的影响主要表现在两个方面,一是灰成分对煤焦气化反应的催化作用,二是灰熔融性影响煤焦气化排渣行为。脱灰既可以除去煤焦中具有催化作用的矿物质,又可以增大煤焦的内表面积。     

配煤对煤灰熔点的影响及灰熔点预测模型研究

针对皖北刘桥二矿煤（A）属于高灰熔点煤,无法满足Shell气化炉液态排渣的需要。考察了采用配煤技术降低煤A的灰熔点的效果,结果表明,配煤可以显著的降低煤A的高灰熔融性。使其能够满足Shell气化炉液态排渣工艺的要求。并采用最小二乘法对灰熔点与煤灰灰成分之间建立并回归了预测模型,预测模型方程表明,若能增加配煤煤灰中MgO的含量可显著降低煤灰熔点,增加配煤煤灰中CaO的含量可使煤灰熔点降低,在煤灰中SiO2和Al2O3总含量一定的条件下,高硅低铝的配煤煤灰可进一步降低煤灰熔点。同时该模型能较好地预测三种原煤配煤的灰熔点。     

COAL PROPERTY EFFECTS ON N2O AND NOx FORMATION FROM CIRCULATING FLUIDIZED BED COMBUSTION OF COAL

The effects of coal properties on N₂O and NO_x formation from circulating fluidized bed combustion of coal was examined through burning nine typical coals and a coal shale, widely used in China over a wide range of coal ranks, in a bench-scale circulating fluidized bed. It was found that N₂O and NO_x formation had similar dependence on coal rank. Fixed carbon content and nitrogen content were the most important coal properties to influence N₂O and NO_x emissions from circulating fluidized bed combustion of coal. A coal with high fixed carbon content had high conversion ratio of fuel-N into N₂O and NO_x. The conversion ratio of fuel-N into N₂O or NO_x increased with nitrogen content of coal, whereas it decreased with O/N ratio. No significant correlation between conversion ratio of fuel-N into N₂O or NO_x and C/N ratio was identified. To clarify the coal property effect, investigation of a wide range of coal rank, is important.     

浮选对煤热解过程中NH_3生成的影响

介绍了采用固定床反应器对神东、新疆和小龙潭原煤及其浮选后所得精煤和尾煤在873K～1 173K温度、420mL/min Ar气氛下热解NH_3生成的实验研究。结果表明,浮选得到的精煤和尾煤在热解过程中释放的NH_3量与原煤释放的NH_3量相比不同,且随煤的变质程度的变化而变化;浮选改变了NH_3的生成率,但没有改变其随温度的变化趋势。精煤、尾煤与原煤一样,在快速热解过程中,NH_3的生成由进样阶段决定。煤氮生成NH_3的转化率均随着温度的升高而增大,但高于1 173K时,NH_3的生成率变化不大;精煤在程序升温热解和快速升温热解过程中,生成的NH_3均比原煤少,尾煤在两种热解条件下表现不同。实验证明,浮选改变了NH_3的生成率,而且NH_3的生成率和煤中所含的S及矿物质有关。     

Comparison of chars in slag and fly ash as formed in pf boilers from B?dzin Power Station (Poland)

The amount of unburned organic matter in solid residues from coal combustion process is one of the indicators of the process and may influence their usage as by products. During the examination of slag and fly ash from B?dzin Power Station (Poland) the following forms of unburned coal were distinguished: crassispheres, tenuispheres, isotropic and anisotropic networks, tenuinetworks, honeycombs, inertinite and detritus. Slag characterises higher crassispheres and networks contents while high detritus contents are typical of fly ash. Spheres content in both slag and fly ash is always lower than vitrinite content in the feed coal. Fusinite content in the feed coal is lower than inertinite content in the solid residues. Other inertinite macerals probably participated in the formation of honeycombs.     

内构件固定床反应器中不同水分煤的热解特性

通过在有无内构件(传热板和中心集气管)固定床反应器中研究不同水分含量煤的热解特性,考察了两反应器中煤料的升温特性、热解产物分布、焦油品质以及气体产物组成和半焦热值。结果表明,内构件可以强化传热和调节热解产物在反应器内的流动,相对无内构件反应器,有内构件反应器的反应时间缩短近一半。在有内构件反应器中,当煤水分增加,导致煤热解反应要求的时间延长,焦油中轻质组分(沸点低于360℃)含量明显升高,焦油收率先增加后降低,热解水和热解气产率升高,而无内构件反应器的热解产物无明显差异。当加热温度900℃时,煤水分从0.41%(本文中无特殊说明的均为质量分数) 增加至11.68%,焦油产率从9.21%增长到10.74%;当煤水分增加到15.93%,焦油产量下降到10.26%。两反应器气体平均组成随水分增加的变化趋势相似,气体热值均随水分增加呈下降趋势。     

中国煤中氮含量的分布研究

系统地研究了中国煤中氮含量的分布。结果表明不同地区、不同时代、不同煤类煤中的氮含量均有显著的差异,早、中侏罗世煤的氮含量最低,第三纪煤的氮含量最高。随着变质程度的增加,煤中氮含量降低,肥煤阶段以后,煤中氮含量随变质程度增高而明显降低。     

焦炭气化反应性对抚顺气煤容惰能力的评价

气煤是储量最丰富的炼焦煤,科学地评价其容惰能力对于提高气煤在配煤炼焦中的使用及降低配煤成本具有重要意义。本文将抚顺气煤的镜质组富集纯化后配入惰性组分（标准无烟煤）炼焦,以焦炭的气化反应特性评价抚顺气煤镜质组的容惰能力,并提出综合气化特性指数（G）、气化起始指数（G_s）、气化终止指数（G_d）3个指数考察焦炭的气化反应特性。研究结果表明,G、G_s、G_d随惰性组分的增加呈减小的趋势,且惰性组分质量分数为40%时,G、G_s、G_d出现骤降。运用Ozawa积分法计算气化活化能表明惰性组分配入量在20%~60%时,40%惰性组分的活化能相对较大。XRD和SEM分析也表明,惰性组分质量分数为40%时,所得焦炭基质致密均匀,芳香度大,晶格缺陷少。所以,抚顺气煤镜质组配入惰性组分的极限值是40%。