Extracting vanadium from stone-coal by oxygen pressure acid leaching and solvent extraction

Vanadium extraction from stone-coal was investigated by oxygen pressure acid leaching and solvent extraction.The mineralogy of the stone-coal from Tongren City of Guizhou Province,China,was investigated by various determination methods. The effects of leaching time,leaching temperature,leaching agent concentration,leaching L/S ratio,granularity of material,additive consumption were investigated based on the mineralogy.The results show that under the conditions of leaching time of 3-4 h, temperature of 150℃,sulfuric acid consumption of 25%?30%,ratio of liquid to solid of 1.2:1,the granularity less than 0.074 mm, additive consumption of 3%-5%,and oxygen pressure of 1.2 MPa,and the vanadium leaching rate can be more than 92%by the method of two-step pressurized acid leaching.The powdery V2O5 product with 99.52%in V2O5 content is obtained by the flowsheet of acid recovery,removing iron by reduction process,solvent extraction,precipitating vanadium with ammonium water,and pyrolysis from the stone-coal oxygen pressure acid-leaching solution.The total recovery efficiency of vanadium is above 85%,which is more than 20%higher than that obtained in the conventional process.Furthermore,the new process does not cause air pollution since no HCl or Cl2 is released by calcination of the raw material.

The mechanism and products for co-thermal extraction of biomass and low-rank coal with NMP

The high-value utilization of low-rank coal would allow for expanding energy sources,improving energy efficiencies,and alleviating environmental issues.In order to use low-rank coal effectively,the hypercoals(HPCs)were co-extracted from two types of low-rank coal and biomass via N-methyl-2-purrolidinone(NMP)under mild conditions.The structures of the HPCs and residues were characterized by proximate and ultimate analysis,Raman spectra,and Fourier transform infrared(FT-IR)spectra.The carbon structure changes within the raw coals and HPCs were discussed.The individual thermal dissolution of Xibu(XB)coal,Guandi(GD)coal,and the biomass demonstrated that the biomass provided the lowest thermal dissolution yield Y1 and the highest thermal soluble yield Y2 at 280℃,and the ash content of three HPCs decreased as the extraction temperature rose.Co-thermal extractions in NMP at various coal/biomass mass ratios were performed,demonstrating a positive synergic effect for Y2 in the whole coal/biomass mass ratios.The maximum value of Y2 was 52.25wt% for XB coal obtained with a XB coal/biomass of 50wt% biomass.The maximum value of Y2 was 50.77wt% for GD coal obtained with a GD coal/biomass of 1:4.The difference for the optimal coal/biomass mass ratios between XB and GD coals could be attributed to the different co-extraction mechanisms for this two type coals.

Degradative solvent extraction of low-rank coal:Role of water on pyrolysis mechanism of low-rank coal in a highly-dispersed medium

A degradative solvent extraction(DSE)method was proposed to upgrade low-rank coals(LRC)for their cascaded utilizations in a highly-dispersed medium.The derived products exhibited well improved properties in comparison to the raw LRCs.Previously,the LRCs were pre-dried to eliminate the potential impact of the varied water content of raw LRCs,but in light of the abundant water in fresh coals,the hydrolyzing effect of water on coals under heating,and the energy cost to pre-dry the LRCs,it is consequently essential to clarify the effect of water so as to verify the necessity of pre-drying process.In this study,the roles of inherent water and extra-added water were respectively investigated,using dried,raw and wet coals from two typical LRCs.The results show that increasing the moisture content of raw LRCs contributed to the extraction ability of DSE method without noticeably changing the elemental composition,chemical structure and thermal decomposition behavior of extractable products,thus pre-drying of LRCs before DSE treatment was proven unnecessary.Additionally,the roles of the inherent water were concluded as:1)leading to the formation of stable covalent bond during drying process;and 2)acting as H donor to promote extraction ability,while the added water can only function as H donor.Since excessive water will increase the pressure during DSE treatment and lead to the waste water treatment,the LRCs with a water content between 10%and 30%were consequently recommended for the practical application of DSE treatment.

CS_2 extraction and FTIR & GC/MS analysis of a Chinese brown coal

The abundance of low-rank coals in China, such as bituminous and brown coals, makes studies of their composition and structure of great significance to both coal chemistry research and for efficient utilization of the coal. We describe how a Chinese brown coal was ultrasonically extracted with carbon disulfide （CS2） and the raw and extracted coals were characterized by Fourier Transform Infrared Spectroscopy （FTIR）. The corresponding extract was analyzed with a coupled gas chromatograph mass spectrometer （GC/MS）. The FTIR analysis shows a great abundance of amidocyanogen, carbonyl, aromatic and hetero aromatic rings and single carbon-beteroatom bonds. This suggests the possible occurrence of compounds like alcohols, phenols, amines, esters, carboxylic acids, ethers, aromatics or heteroaromatics. The GC/MS analysis of the CS2 extract detected 62 compounds, among which the non-polar ones were of lower abundance while the polar ones were in higher abundance and were structurally diverse. This demonstrates the compositional and structural complexity of Shengli coal.

Study of Constituents of Fractionated Extraction from Datong Coal

Datong coal was extracted with CS2, n-hexane, benzene, methanol, acetone, tetrahydro-furan（THF） and THF/methanol（1：3,v/v） mixed solvent sequentially. The extracts were analyzed with GC/MS. It is presented that group seperation of soluble organic compounds in the coal can be achieved by fractionated extraction using different solvents. The results show that CS2 was effective for extracting arenes from the coal sample, n-Hexane extractable fraction from Datong coal mainly consists of n-alkanes. A great variety of oxygen-containing compounds are dominant in the components of methanol-soluble fraction. Acyclic isoprenoids, pentecyclic triterpanes and a series of cyclohexanes with long-chain alkyl-substitutes are detected in acetone-soluble fraction. Dicyclic aramatic hydrocarbons are identified in benzene-soluble fraction and 4-6 cyclic condensed aramatic hydrocarbons are identified in THF-soluble fraction. The molecular structures detection of 1,2-dichlorobenzene, 2,4-dibromophnol, 2,4,6-tribromophenol and 4-chlorobenzophenone firstly provide information for existence form of bromine and chlorine in coal.

Carbon monoxide adsorptive capability of low rank coal's maceral

The centrifugal separation with gravity experiment was made for getting every pure macerals like inertinite and vitrinite,and the isothermal adsorption tests of pure mac- eral are carried out at 30,40,50,55,60,65℃,respectively,after analyzing the proximate element and maceral of coal samples,which was aimed to study the CO adsorptive capa- bility of every maceral of low rank coal at difference temperature and pressure.The results show that the adsorption isotherm of CO can be described by Langmuir equation because it belongs to the Type I adsorption isotherm at low temperature(T≤50℃),and the tem- perature effect on coal adsorption is greater than of pressure in lower temperature and pressure area;what's more,the relationship is linear between the coal adsorption quantity of CO and the pressure at high temperature(T>50℃),it can be described by Henry equation(Q=KP),which increases with pressure.Both temperature and pressure has great influence on CO adsorptive capability of low rank coals,especially the temperature's effect is so very complex that the mechanism need to study further.At the same time,the volatile matter,inertinite,oxygen-function groups and negative functional groups are high popu- larly in low rank coal samples,especially,the content of hydroxide(-OH) has great influ- ence on CO adsorption in that the inertinite has stronger effect than vitrinite on adsorptive capability of low rank coal samples,the result is same to the research on CH4 adsorption.

Degradative solvent extraction of subbituminous coal with deep eutectic solvent and effect of reaction conditions on products

A degradative solvent extraction method for upgrading low-rank coal was performed at 200-350◦C for 90 min to obtain a substance dissolved in the solvent at room temperature(Soluble).Because the resulting mixture exhibited a high carbon content without ash,it could be readily used as a fuel.Furthermore,deep eutectic solvents(DESs)have attracted attention for improving the Soluble yield and decreasing the oxygen content in Soluble.DES is known to cleave oxygen-containing functional groups in biomass and is considered effective for deoxidizing low-rank coal.Herein,DES was prepared by mixing choline chloride,FeCl3⋅6H2O,and Adaro subbituminous coal(AD)and then added to 1-methylnaphthalene(1-MN)in a non-polar solvent,followed by degradative solvent extraction in the range of 200-350◦C.The effects of reaction temperature and added DES amount on the product yield and the composition were evaluated.As the reaction temperature and amount of DES added increased,the Soluble yield and carbon content increased.It was also found that the thermal decomposition temperature and oxygen content decreased with the increasing DES amounts.This decrease indicates that DES promotes the deoxygenation and decomposition of AD and increases the soluble yield of the fuel source.

A new process of extracting vanadium from stone coal

A new process of extracting vanadium from the stone coal vanadium ore in Fangshankou, Dtmhuang area of Gansu Province, China was introduced. Various leaching experiments were carried out, and the results show that the vanadium ore in Fangshankou is difficult to process due to its high consumption of acid and the high leaching rate of impurities. However, the leaching rate can be up to 80% and the content of V2O5 in the residue can be between 0.22%-0.25% in the process of ore fme grinding→oxidation roasting→mixing and ripening→aqueous leaching→P2O4 solvent extraction→sulfuric acid stripping→oxidation and precipitation→decomposition by heat. Also, the quality of flaky V205 produced by this process can meet the requirements of GB3283--87. The total leaching rate of vanadium is 70%. Also, three types of wastes are easy to treat. The vanadium extraction process is better in relation to the aspect of environmental protection than the sodium method.

Non-covalent associative structure of coal

The recent progress of non-covalent associative structure of coal, and the mechanisms of the CS2/NMP (1:1 by volume) mixed solvent and the additive addition enhancing the extraction yield of coals were reviewed, and the aggregation behavior of coal in solid and solution states were presented, and the aggregation behavior of coal in solid and solution states were introduced in this paper. Coal extraction and swelling in organic solvents at room temperature were the most useful methods to understand the associative structure of coal. CS2/NMP (1:1 by volume) is a unique solvent to give high extraction yields for some bituminous coals. Some additives can dissociate the stronger interactions among coal molecules and enhance the extraction yields of coal in the mixed solvent.

Fractionation of coal through organo-separative refining for enhancing its potential for the CO2-gasification

Coal gasification has already been extensively studied earlier under varying conditions of steam,CO2,O2,inert conditions.Belbaid coal and its e,N and NMP-DETA SCC products recovered through organo-refining under milder ambient pressure conditions were subjected to CO2-gasification in a fixed bed reactor under varying conditions.CO2 being an inert gas becomes the most challenging to be utilized during the gasification process.The SCCs showed better CO2-gasification reactivity than the raw Belbaid coal at 900°C.The use of the catalyst K2CO3 tremendously increased the gasification reactivity for both raw coal and the SCCs.The use of sugarcane bagasse for CO2-gasification along with raw coal as well as with residual coal was also studied.Gasification under CO2 atmosphere conditions was used to structurally understand the coals as the coal structure gets loosened after extraction.

中国HyperCoal清洁高值化应用研究现状与展望

作为一个煤炭大国,煤炭在我国的能源结构中占据重要地位.然而,煤炭的过度使用不可避免的造成了环境污染和温室效应等问题.因此发展洁净煤技术是解决煤炭利用问题的重要方式,对于我国经济的可持续发展至关重要.HyperCoal(HPC)是通过溶剂萃取技术得到的一种煤衍生物,由于具有低灰、低水、高热值、高反应性、良好热塑性、环境友好等特性,在洁净煤技术中有着重要的应用.基于此,本文指出了目前我国对HPC的应用研究现状,并详细阐述了本研究团队在配煤炼焦和制备石墨电极领域的突破性研究进展.然而,目前HPC在推广和应用过程中还存在一些问题.在未来,还亟需解决HPC的规模化生产问题,并对HPC的萃取机理和作用机制开展更加深入的研究.

A comparative study on demineralization of coals by acid-washing and solvent-extraction methods for low temperature catalytic coal gasification application

Catalytic coal gasification is an efficient way to achieve high conversion rates at low temperatures.Catalyst loss due to the reaction between the inherent mineral matter in the coal and the catalyst is a major hurdle for its practical application.The problem may be overcome by removing the mineral matter from the coal before use.Two demineralizing approaches,acid-washing and solvent-extraction methods are investigated for demineralizing the coals.Elemental analysis,XRD analysis,NMR analysis,and N_(2)adsorption analysis were made to compare the demineralization efficiency,crystallographic carbon microstructure,chemical structure,and micro-porosity,respectively.Solvent-extraction method was found be more efficient for demineralization.Difference was observed in the chemical structure and micro-porosity while crystallographic carbon-microstructure was found to be similar.Non-catalytic and catalytic gasification reactivity of the chars obtained by the two methods was compared.Gas composition and gas evolution profiles were also obtained and found to be influenced by the degree of demineralization.

低阶煤热溶萃取物的配煤炼焦性能

目前,使用黏结性添加物进行配煤炼焦,降低焦/肥煤的使用比例,是焦化行业降本增效的重要途径。国内外学者已经在实验室阶段初步证明了低阶煤热溶萃取物替代焦/肥煤炼焦的可行性,工业化应用需要开展大规模的萃取物炼焦实际验证。基于此,本文搭建了低阶煤热溶萃取装置,并与多家焦化厂展开合作,完成了萃取物替代焦/肥煤的小焦炉实验验证。结果表明:萃取物取代20%肥煤或10%焦煤时能够明显降低焦炭的灰分,保持焦炭冷热性能基本不变。并且萃取物在炼焦过程中有72%~77%的留存率,不会造成焦炭产量的明显降低。因此,本研究明确了低阶煤热溶萃取物取代焦/肥煤炼焦方案的可行性,为焦化行业的降本增效提供了新选择,并进一步推动了低阶煤热溶萃取技术的工业化进展。

低阶煤溶剂萃取技术研究进展

我国低阶煤资源十分丰富,占全国煤炭资源总预测储量的57.38%。低阶煤由于具有高灰、高水、黏结性差、热值低等特点,很难被直接用于炼焦及煤液化、气化中,从而造成了资源浪费。溶剂萃取工艺利用相似相溶原理对低阶煤的碳骨架结构溶胀提质制备改质煤,该煤种具有无灰、高结焦性和高热值的特点。本文介绍了不同溶剂类型如极性溶剂、非极性溶剂、混合溶剂以及生物质协同对煤粉的萃取效果,综述了不同反应条件如碱预处理、温度、初始压力、煤粉粒径、煤粉性能等对煤粉萃取率的影响机理。未来,应加强联合萃取剂法对低阶煤萃取机理的研究,通过正交试验筛选出更多适合低阶煤联合萃取的生物质,并综合考虑反应条件和煤粉性质对低阶煤萃取的影响。

高煤阶煤层气井压降扩展规律研究及应用——以沁水盆地樊庄区块为例

文章以沁水盆地樊庄区块直井为研究对象,综合考虑因排采降压差异导致的储层渗透率动态变化这一特征,通过搭建应力-压缩性-渗透性三者之间的关系,构建了适用于高煤阶煤储层的气-水流动模型,同时分别对单相产水阶段、两相采气阶段的压降扩展规律进行了量化分析,理清了樊庄区块煤层气井压降扩展规律,从而优化了现场单井排采制度。结果表明:在采气阶段存在最佳提气速度,其次确定了影响煤储层压降扩展的6个主控因素,拟合得到了采气阶段-最佳提气速度预测公式,为樊庄区块及类似地区煤层气井的排采管控提供了指导依据。

地下煤气化合成气的脱碳提氢耦合工艺探讨

针对煤炭地下气化(UCG)技术制备的合成气具有温度高(>200℃)、压力大(3.35 MPa)、饱和含水量大及组分复杂(含CH_(4)、H_(2)、CO_(2)和CO等)的特点,设计并采用膜分离+溶剂吸收耦合的处理方法以实现地下煤合成气中CO_(2)的脱除和H_(2)的提纯。地下煤合成气经过二级膜分离单元的处理,实现了CO_(2)/H_(2)与CH_(4)的分离并得到了脱碳净化气,其中CO_(2)含量(物质的量分数)≤3%,该膜分离工艺所需能耗为0.297 k W·h/m^(3)。使用醇胺吸收法处理CO_(2)/H_(2)混合气,并通过配方溶液筛选、工艺流程优化和校验分析等方法开展了研究,最终得到了H_(2)纯度(物质的量分数)≥99%的产品,该醇胺吸收法的能耗为0.341 k W·h/m^(3)。使用膜分离+溶剂吸收耦合处理复杂工况的地下煤合成气,可得到脱碳净化气、纯CO_(2)和工业级H_(2),提高了项目的经济价值,具有较大的应用潜力。

基于流程模拟的萃取脱酚研究

煤化工废水的治理和处理成为当今社会亟待解决的问题,流程模拟是一种在计算机模拟环境中研究和优化工业流程的方法,具有很高的灵活性和可控性。实验利用SBAC对煤化工废水进行基于流程模拟的萃取脱酚,结果表明,SBAC对总酚的萃取效果明显更优,随着相比的减小,SBAC的萃取率优势将更为明显。经过6级萃取之后,对热解废水单元酚的萃取率达到了96.3%,对气化废水单元酚的萃取率为93.7%。通过此次研究,将对煤化工废水的治理和处理提供新的理论基础和实践指导。

特高煤级煤平衡水条件下的吸附实验

鉴于国内外对镜质组最大反射率Ro(max)大于4.0%的特高煤级煤的吸附特性研究的空白,作者系统地采集了12个Ro(max)>4.0%的煤样进行了平衡水条件下的高压等温吸附实验,分析了特高煤级煤样的朗格缪尔常数与Ro(max)、显微煤岩组分、比孔容和比表面积的关系,发现了煤的朗格缪尔体积随煤级变化的拐点是在Ro(max)为4.5%左右。在上述研究的基础上,文中探讨了煤的吸附特征及机理。

煤氧化过程中气体的形成特征与煤自燃指标气体选择

利用氧化模拟实验和色谱分析，结合煤岩学分析，对不同性质煤样在氧化模拟实验过程中生成气体的组成和数量进行了详细分析，提出生成气体的组成和数量在内因上主要取决于煤温、煤阶和显微组分组成３个主要因素。将煤自燃指标气体分为三类，建立各类指标气体与煤温、煤阶、煤岩类型之间的数量关系。煤自燃指标气体产率随煤温上升基本上呈指数上升，但煤自燃指标气体产率与煤温相关关系曲线型式受控于煤阶和显微组分组成。不同煤阶煤应采用不同类型的煤自燃指标气体，第一类指标气体主要适用于低变质褐煤和长焰煤阶段，而第二、第三类指标气体主要适用于高、中挥发分烟煤阶段，根据指标气体与煤温相关关系以及指标气体的选择原则，分析了平庄古山矿和枣庄柴里矿煤自燃指标气体应用实践。

煤的溶剂抽提规律及其产物性能的研究进展

阐述了温和条件下煤的溶剂抽提机理 ,煤分子间作用力、溶剂种类对抽提率的影响、抽出物的洁净性能、抽余物的吸附性能、抽提产物表面的物化以及表面活性剂对煤的亲水 /疏水性、ξ电位和氮气吸附性能的影响 .结果表明 ,对于高阶煤 ,加入中性活性剂 Teric G1 2 A8可以有效降低其 ξ电位 ,增大其氮气吸附量和疏水性 .