脱硫菌磁化培育及生物浸出脱除煤中黄铁矿硫的研究

将磁化技术用于煤炭脱硫菌种的培育，研究了磁化培育下的中国煤系与非煤系氧化亚铁硫杆菌对煤中黄铁矿硫的脱除效果。研究表明，磁化环境对矿质化学营养脱硫菌氧化亚铁硫杆菌的生长具有促进作用，一定磁化培育条件下的煤系氧化亚铁硫杆菌对小于0．075mm的煤样浸出24d的最大脱硫率（86．16％）高于非煤系氧化亚铁硫杆菌的最大脱硫率（82．56％），磁化培育下的煤系氧化亚铁硫杆菌具有更好的脱除煤中黄铁矿硫的效果。     

国外煤炭燃前脱硫综述

<正> 一、微生物脱硫能够应用于煤脱硫领域的微生物种类很多,目前广泛采用的是硫杆菌属的氧化亚铁硫杆菌和氧化硫硫杆菌。Brierly 于70年代末期从酸性热温泉和富硫土壤中分离出了嗜热铁氧化菌。80年代末,美国大西洋研究公司成功地从自然生物种群中分离出了 CB1和CB2,这两种微生物对脱除煤中的噻吩硫等有机硫有特效。国外微生物脱除煤中无机硫的研究十分     

高硫煤全氯乙烯脱硫新工艺

本文介绍了美国全氯乙烯脱煤中有机硫及黄铁矿与矿物质新工艺的开发状况和主要结果。用全氯乙烯萃取煤中有机硫,可脱除煤中30～70%的有机硫,全氯乙烯同时还用作重介质,浮选煤中黄铁矿和矿物质,可脱除90%以上的黄铁矿。该过程热值回收率在86.3～96.5%之间。由于脱除了煤中的矿物质和水分,洁净煤的热值比原煤高40～50%。全氯乙烯脱硫工艺具有操作条件温和、效率高、能量回收率高和选择性好的优点。该工艺除了可得到低硫低灰的洁净煤外,硫可以以硫磺的形式回收:经过多级全氯乙烯浮选,黄铁矿可浓缩到80%以上;全氯乙烯全部循环使用,因而不会对环境造成新的污染。     

用氧化铁硫杆菌和煤中存在的混合嗜酸细菌脱除煤里的硫

用氧化铁硫杆菌菌种处理三个煤样,已有效地除去了黄铁矿硫。同时发现煤里的嗜酸细菌有效地从煤里浸提出黄铁矿。添加必需的细菌营养品和表面活化剂,并脱除煤里的方解石,有利于该浸提过程。通过这个过程,除了黄铁矿硫以外,大量的硫酸盐硫和少量的有机硫也被脱除。     

酸性条件下电解脱硫对煤质的影响

为研究HCl电解质体系中电化学脱硫对煤质的影响,利用扫描电镜(SEM)、X射线荧光光谱(XRF)、X-射线衍射(XRD)、红外光谱(FT-IR)等分析方法对原煤和脱硫后煤样进行成分分析,研究煤中矿物化学成分、矿物元素含量、黄铁矿分布形态、煤表面官能团变化等。结果表明,在电解质为HCl,电流密度0.044 A/cm2,煤浆质量浓度0.02 g/m L,电解质浓度0.75 mol/L,煤粒度小于0.5 mm的条件下,电化学脱硫法可有效脱除煤中硫,全硫脱除率为76.32%,其中有机硫、无机硫脱除率分别为62.32%和82.80%,基本实现无机硫和有机硫的同步脱除;煤中灰分较脱硫前降低了9.38%,精煤发热量增加了0.70 MJ/kg,表明电化学脱硫法基本不破坏煤的原有结构,有助于改善煤质。     

煤的电化学脱硫机理研究

本文在研究煤的电化学脱硫基础上 ,利用 X-射线衍射和红外光谱等现代测试手段研究了煤中无机硫和煤系黄铁矿硫的电化学脱硫机理。研究表明煤中无机硫和煤系黄铁矿硫的脱硫机理有相似之处。首先在电极表面产生活性氧或高价离子 ,活性氧氧化煤或煤系黄铁矿中无机硫为单质硫或硫酸盐硫。其中煤中硫氧化为硫酸盐硫 ,煤系黄铁矿硫氧化为硫或硫酸盐硫。     

煤的生物加工

借助计算机对国际上关于煤及有关的有机化合物的微生物转化方面的文献进行了调研和述评,以便确定可能应用于煤生物加工的候选微生物和生物技术。关于煤生物加工的大多数文献都是论及通过脱除黄铁矿来脱硫,并提出了一些生物加工流程。最近还发表了脱除煤中有机硫和金属的几篇报告。到目前为止,还没有评述脱除煤中其他元素(如氧和氮)的文献。然而,用微生物降解了类似煤中某些重要含氧和合氮官能团的模型基质。这些微生物可能有希望用于煤的生物加工。     

用重力——化学法使煤脱硫

Meyers法是一种工艺,它借助于温和的氧化处理,使煤中所有黄铁矿硫基本上得到化学脱除。痕量元素铅、镉及砷这些重要的污染物也可同时被脱除。已经得知:这一方法对于给工业锅炉和较小型的电厂提供合格煤,以及对于在采煤和洗煤操作中所弃去的粉煤的回收和脱硫,都特别经济有效。它是氧化脱硫(用氧气或空气处理煤和水形成的浆液,化学脱除煤中的硫)新技术中最先进的一类。为适应对这一工艺进行判明的需要,     

应用XPS研究煤中有机硫在脱硫时的存在形态

应用Ｘ－射线光电能谱（ＸＰＳ）研究了几种煤中有机硫在脱硫过程中的存在形态。通过模型化合物（ｍｏｄｅｌｃｏｍｐｏｕｎｄｓ）中硫的２Ｐ层电子的ＸＰＳ结合能，可用来估算煤中硫的归属，如硫醇，硫醚及噻吩类硫，南桐东林煤中有机硫以噻吩型硫为主，亦存在少量硫醇以醚型硫，兖州北宿１６层煤则以噻粉硫硫氧化合物的为主，用乙醇超临界抽提及高能辐射处理２种煤样，均能脱除一定量的有机硫，初步认为乙醇超临界提法能脱除煤中硫     

高硫炼焦煤中硫元素在热解过程中的迁移规律研究

为探索炼焦煤中硫元素在洗选和热解过程中的迁移规律,选择3种典型炼焦煤,首先研究洗选过程中硫元素的迁移规律,然后在得到洗精煤的基础上,利用1 kg热解试验装置,研究热解过程中炼焦精煤的全硫、黄铁矿硫、硫酸盐硫和有机硫的迁移规律。结果表明,煤炭洗选过程中主要脱除原煤中的黄铁矿硫,在热解过程中,700℃以前,黄铁矿硫脱除较为明显,700℃以后,有机硫脱除更加突出。此外,在高温区域还存在黄铁矿硫、脂肪类硫化物等向噻吩类硫转化的现象。     

Removal of sulphur from coal by Thiobacillus ferroxidans and by mixed acidophilic bacteria present in coal

Pyritic sulphur has effectively been removed from three coal samples by treating with a strain of Thiobacillus ferrooxidans. The acidophilic bacteria present in coals have also been found to efficiently leach pyrite from coal. Addition of an essential bacterial nutrient and a surfactant together with the removal of calcite from coal, favoured the leaching process. Besides pyritic sulphur, significant amount of sulphate sulphur, and a small amount of organic sulphur were removed by the process.     

Elemental sulphur in microbiologically desulphurized coals

Aerobic, acidophilic mixed cultures containing predominantly chemolithoautotrophic Thiobacillus ferrooxidans oxidized 90% of pyritic sulphur from a German bituminous coal when incubated in an airlift reactor at pH values from 2.6 to 1.8 for 12–28 days with pulp densities from 2–30%. The complete sulphur balance measured by elemental analysis of the coal indicates that the total amount of sulphur removed (35–40%) does not correspond to the amount of pyrite oxidized. This is due to an increase in the amount of insoluble sulphate sulphur, analysed as the basic mineral jarosite. At pH values below 1.9 the formation of jarosite was prevented, but the difference between sulphate plus pyrite and the total amount of sulphur, usually claimed to be ‘organic’ sulphur, increased under these conditions. This previously indirectly determined sulphur fraction proved to consist of elemental sulphur and unchanged organic sulphur. The elemental sulphur accumulates during the chemical oxidation of pyrite by ferric ions. The formation of considerable amounts of elemental sulphur was observed with only one out of four coals analysed.     

Biodepyritisation of coal

This review provides a detailed summary of the recent and past research activities in the area of biodesulfurisation of coal. It provides information about microorganisms important for biodesulfurisation of coal, with the emphasis on Thiobacillus ferrooxidans. The review presents an insight into various methods of desulfurisation of coal combining physical and biological methods. Also, there are discussions on coal structure, distribution, mechanism and kinetics of pyrite oxidation and jarosite precipitation. Finally, areas requiring further research are identified. Copyright © 2003 Society of Chemical Industry     

黄铁矿脱硫菌生长和代谢的影响因素研究

研究了氧化亚铁硫杆菌（简称T．f．菌）对几种氮源、能源的利用，以及空气中氧化不同时间的黄铁矿吸附菌的代谢活性。结果表明：在选择的3种氮源中，尿素经过诱导可被T．f．菌较好地利用，说明该菌可产生诱导性脲酶。在选择的能源中，Fe^2＋是T．f．菌容易利用的能源基质。添加接种培养过的残留单质硫粉可提高菌体氧化单质硫的速率。在空气中氧化20d的黄铁矿对T．f．菌的吸附量增大，而且吸附菌体的亚铁氧化过程提前进行。     

Sulphur distribution in Illinois no. 6 coal subjected to different oxidation pre-treatments

The effect of different oxidation pre-treatments on the sulphur distribution in Illinois No. 6 coal (IBC-101) was studied using Atmospheric Pressure-Temperature Programmed Reduction (AP-TPR). Oxidation pre-treatments were carried out on demineralized coal with peroxyacetic acid (PAA) as a function of reaction time. For the longest reaction time the effect of PAA on the coal was compared to the effect of several other oxidants. AP-TPR results also show a clear effect of LiAlH₄ on the coal. Not only is pyrite removed, but there is also a decrease in other sulphur forms. Subsequent PAA oxidation causes an overall decrease of the AP-TPR signal, signifying the attack on organic as well as inorganic sulphur forms. With other oxidants, under the same conditions, only minor differences could be found after different treatments.     

X-ray photoelectron spectroscopic investigation of coal

X-ray photoelectron spectroscopy (XPS) has been used to study the carbon, oxygen and sulphur content of several coking coals, a series of sink—float fractions from a high-volatile coking coal, and several inorganic minerals that are commonly found in coals. Single carbon and oxygen peaks were obtained that corresponded to carbon 1s orbital and oxygen 1s orbital electron binding energies which are expressed in units of electron volts (eV). Two sulphur 2p (S 2p) peaks were found. The 169–171 eV S 2p peak corresponded to the sulphates resulting from the oxidation of pyrite (FeS₂), while the 163–164 eV S 2p peak was assigned to the iron sulphide compounds such as pyrite or marcasite. No separate organic sulphur peaks were found for coal, because the majority of the organic sulphur peaks are probably overlapped by the inorganic sulphide line at 163–164 eV. The total carbon and sulphur determined using the XPS peak height correlated with the chemical analysis, although the accuracy of the XPS determinations seems to be lower. A possible direct quantitative method for determining the organic sulphur in coal by XPS is discussed.     

Removal of sulfur from Assam coal by bacterial conditioning and froth flotation

Reduction of sulfur by bacterial leaching from a high sulfur‐bearing coal sample from Assam was attempted. Flotation of the sample with light diesel oil could not depress the pyrite and also the Thiobacillus ferrooxidans was found to be ineffective in leaching the sulfur from the flotation concentrate. Conditioning of the same coal sample with Thiobacillus ferrooxidans was found to assist in selectively depressing the pyrite, thereby reducing nearly 60% of the pyritic sulfur present in the sample. © 1999 Society of Chemical Industry     

Automated determination of organic sulphur in coal: Use of scanning electron microscopy and energy-dispersive X-ray microanalysis

Scanning electron microscopy combined with energy-dispersive X-ray microanalysis in fully automated form was used for the determination of organic sulphur in coal. The values found by this technique are in good agreement with those found by the usual classical methods, provided the coal has a low content of pyrite. For coals high in pyrite, however, SEM/XRMA gives considerably lower values of organic sulphur. The discrepancy is probably due to the incomplete extraction of pyrite inclusions in the wet analysis leading to a low value for the pyrite content, and consequently, a high value for organic sulphur. Apart from primarily being a method for the determination of organic sulphur, the method presented affords additional information; for example, it may enable a differentiation to be made between a single coal sample and a blend of several types of coal.     

Mild oxidations of coal: 1. Hydrogen peroxide oxidation

Mild oxidation of Pittsburgh bed coal was carried out to investigate the removal of organic sulphur. It was postulated that the organic sulphur in coal might first be oxidized to sulphonic acids and then removed through known desulphonation methods. The coal was oxidized with hydrogen peroxide or mixtures of hydrogen peroxide and acid. After oxidation, the coal was treated with water or phosphoric acid at reflux. Under the mild conditions used, coal oxidation led to slight changes in the organic sulphur content. The ensuing treatment of the oxidized coal with water or phosphoric acid again affected the organic sulphur content, generally decreasing the organic sulphur level. Pyritic sulphur removal varied considerably depending upon the reagent system and reaction conditions.     

An XPS study of the oxidation of pyrite and pyrites in coal

X-ray Photoelectron Spectroscopy (XPS) was used to study mineral, synthetic and coal-associated pyrites, oxidized for various time intervals at low temperatures with humid air or oxygen. This was done to find out if XPS could detect, monitor and clarify pyrite surface-oxidative changes that influence surface-dependent coal-cleaning methods such as froth flotation, and could provide a means of directly analysing coal sulphur, by determining if oxidizing conditions existed which would effectively eliminate the surface pyrite whose XPS peak may occur at the same energy as the organic sulphur peak of coal. The conditions of study were as follows: a mineral and two coals containing pyrite were exposed to air at 24 ± 3 ° C and 33 ± 8% relative humidity up to 600 h; two mineral pyrites were exposed to oxygen at 100% relative humidity and 35 ° C for up to 200 h; and the two mineral and a synthetic pyrite were exposed to oxygen at 100% relative humidity and 55 ° C for up to 300 h and at 72°C for 25 h. The results indicated that the XPS S2p pyrite peak at ≈169 eV and the surface-oxidation-product(s) peak(s) at ≈163 eV could be detected and followed with XPS, although no conclusions could be made about the oxidation mechanism. The pyrite XPS peak became small compared to that of its oxidation products when the synthetic and mineral pyrites were exposed to 55 ° C oxygen at 100% relative humidity for 300 h. These conditions may prove useful in trying to determine directly the organic sulphur in coal.