Discharge characteristics of coal and extraction residue from direct coal liquefaction in partial fluidization silo

Gasification of extraction residue(ER) from direct coal liquefaction with pulverized coal is an efficient way for the utilization of carbonaceous wastes, which improve the overall efficiency of direct coal liquefaction technology. The discharge characteristics of ER mixing with pulverized coal is important paraments for its gasification process, which is seldom studied in the literature. In this study, the discharge characteristics of the pulverized coal(M1) as well as its mixture with ER(M2) were systematically investigated in an atmospheric pressure partial fluidization silo with different fluidization apparent velocity. It was observed that although M2 is a viscous powder with lower flowability than M1, the mass flow rate of M2 is 65% higher than M1 at the 3.7 mm·s-1apparent gas velocity. M2 exhibits the properties of Geldart A type powder, which improves the mass flow rate and stability of the discharged material. The mass flow rate of both M1 and M2 first increases and then slowly decreases with the increase of apparent gas velocity of the fluidizing air, which means the discharge process of M1 and M2 can be optimized by the apparent gas velocity.

Preparation of mesoporous activated carbons from coal liquefaction residue for methane decomposition

Mesoporous activated carbons were prepared from direct coal liquefaction residue （CLR） by KOH activation method, and the experiments were carried out to investigate the effects of KOH/CLR ratio, solvent for mixing the CLR and KOH, and carbonization procedure on the resultant carbon texture and catalytic activity for catalytic methane decomposition （CMD）. The results showed that optimal KOH/CLR ratio of 2 ： 1; solvent with higher solubility to KOH or the CLR, and an appropriate carbonization procedure are conductive to improving the carbon pore structure and catalytic activity for CMD. The resultant mesoporous carbons show higher and more stable activity than microporous carbons. Additionally, the relationship between the carbon textural properties and the catalytic activity for CMD was also discussed.

Mechanisms and characteristics of mesocarbon microbeads prepared by co-carbonization of coal tar pitch and direct coal liquefaction residue

DCLR-P was prepared by direct coal liquefaction residue (DCLR) with ash removal.In the present experiments,mesocarbon microbeads (MCMBs) were prepared by co-carbonization of coal tar pitch (CTP) and DCLR-P.With the increase of DCLR-P content,the yield of MCMBs increased from 47.8% to 56.8%.At the same time,the particle sizes distribution of MCMBs was narrowed,resulting in the decrease of D9o/D10 ratio from 154.88 to 6.53.The results showed that DCLR-P had a positive effect on the preparation of MCMBs.1H-NMR,FTIR,SEM and XRD were used to analyze the mechanisms and characteristics of MCMBs prepared by co-carbonization of CTP and DCLR-P.The results showed that the Proton Donor Quality Index (PDQI) of DCLR-P was 13.32,significantly higher than that of CTP (0.83).This indicated that DCLR-P had more naphthenic structure than CTP,which leads to hydrogen transferring in polycondensation reaction.The aliphatic structure of DCLR-P can improve the solubility and fusibility of mesophase,thereby making the structure of MCMBs more structured.The microstructure of the graphitized MCMBs had a substantially parallel carbon layer useful for its electrical performance.The performance of graphitized MCMBs as a negative electrode material for Li-ion batteries was tested.The particle sizes,tap density,specific surface area and initial charge-discharge efficiency of graphitized MCMBs met the requirements of CMB-I in GB/T-24533-2009.However,the initial discharge capacity of graphitized MCMB was only 296.3 mA h g-1 due to the low degree of graphitization of MCMBs.

XPS analysis and combustibility of residues from two coals extraction with sub-and supercritical water

Two kinds of residues,obtained from extraction of one weakly reductive coal,Shenfu-Dongsheng coal(SD),and one reductive coal,Pingshuo coal(PS),with sub-and supercritical water on a semi-continuous apparatus,were characterized by calorific value analysis and XPS analysis,and the combustion behaviors of residues were investigated by thermogravimetric analysis.The results show that the residues have higher calorific value than raw coal samples,and SD residue has higher calorific value than PS residue.C-C,C-O and pyridinic nitrogen,pyrrolic nitrogen are the dominant form of C,O and N on the surface of raw coal samples and their extraction residues.The combustion behaviors of extraction residues show that the SD residue is more reactive and more easily burned than PS residue.

Oxidation of Lingwu Coal Extraction Residue in Aqueous Sodium Hypochlorite under Mild Conditions

To investigate the structural features and provide an alternative method for high value-added utilization of coal, Lingwu coal was first extracted with organic solvent at room temperature. Then its extraction residue was oxidized in aqueous sodium hypochlorite(ASHC) under mild conditions. The effects of oxidation conditions, such as temperature, reaction time, the ratio of Lingwu coal extraction residue(LCER, g) to ASHC(m L) and p H value, on the product distributions and compositions were investigated. The results of gas chromatography/mass spectrometry(GC/MS) suggested that 53 kinds of methyl esterified products were detected in total, and benzene carboxylic acids were the main oxidation products, while chloro-substituted benzene carboxylic acids were the main by-products. Higher yield and fewer kinds of organic acids could be obtained at lower p H value, especially for the main objective product, benzene carboxylic acids.

Co-pyrolysis characteristics and interaction route between low-rank coals and Shenhua coal direct liquefaction residue

To reasonably utilize the coal direct liquefaction residue(DLR), contrasting research on the co-pyrolysis between different low-rank coals and DLR was investigated using a TGA coupled with an FT-IR spectrophotometer and a fixed-bed reactor. GC–MS, FTIR, and XRD were used to explore the reaction mechanisms of the various co-pyrolysis processes. Based on the TGA results, it was confirmed that the tetrahydrofuran insoluble fraction of DLR helped to catalyze the conversion reaction of lignite. Also, the addition of DLR improved the yield of tar in the fixed-bed, with altering the composition of the tar. Moreover, a kinetic analysis during the co-pyrolysis was conducted using a distributed activation energy model. The co-pyrolysis reactions showed an approximate double-Gaussian distribution.

Compatibility Evaluation between Direct Coal Liquefaction Residue and Bitumen

The compatibility between direct coal liquefaction residue(DCLR) and five kinds of pure bitumen(Shell-90,SK-90, ZSY-70, DM-70 and KLMY-50) was evaluated in this study. The rheological characteristics, glass transition temperatures(T_g), solubility parameters(SP) and SARA(saturates, aromatics, resins, and asphaltenes) fractions of DCLR,five kinds of pure bitumen and their blends(named as DCLR modified bitumen) were measured using the dynamic shear rheometer(DSR), differential scanning calorimetry(DSC), viscosity, and SARA tests, respectively. And the compatibility between DCLR and pure bitumen was characterized with three approaches, viz. the Cole-Cole plot,T_g, and the solubility parameter difference(SPD) method. Since each method has its own working mechanism, the compatibility ranking for the DCLR and five kinds of pure bitumen is slightly different according to the three approaches. However, the difference is pretty close and sometimes can be ignored. The general compatibility ranking decreases in the following order: Shell-90≈SK-90>DM-70≈ZSY-70>KLMY-50, which is affected by the asphaltenes content and the colloid index(I_c) value in the pure bitumen. Pure bitumen with lower asphaltenes content and colloid index(I_c) value has better compatibility with DCLR.

Study on the corrosion of refractory materials by coal blended with the extraction residue of direct coal liquefaction in a simulated gasification atmosphere

Utilizing the extraction residue(ER)of direct coal liquefaction residue as a gasification feedstock has significant economic value.But the characteristic of high ash and iron in the ER would increase the risk of corrosion of the refractory materials and affect the long-term operation of the gasifier.In this work,corrosion experiments of molten slag derived from a mixture of 20 wt%ER and 80 wt%coal on a high-chromia refractory brick and SiC brick were carried out using a rotary-drum furnace in a simulated gasification atmosphere.The experimental results show that the viscosity of the poured slag is larger as compared to the initial ash sample at the same temperature,which suggests that the viscosity-temperature relationship of the poured slag should be used as the reference for the operation temperature of the gasifier to ensure that the slag can flow during operation.For a high-chromia refractory brick,iron oxides in molten slag could react with Cr_(2)O_(3) in the refractory matrix but,because the aggregate was not found to be damaged,the damage to the matrix structure was the key factor for causing the corrosion of the high-chromia refractory brick.Metallic iron was observed in the exposed SiC brick,which indicated that the reaction between the iron oxides in the slag and SiC occurred,forming metallic iron and SiO_(2).The corrosion of a SiC brick by molten slag depended mainly on the dissolution of Al_(2)O_(3) particles and the reaction between iron oxides in the molten slag and SiC particles.Therefore,the high iron content in coal ash had a serious influence on the corrosion of refractory materials.More efforts need to be made on coal blended with ER as a gasification feedstock in the future.

煤液化残渣诱导缩聚制备冶金焦的影响因素

煤液化残渣所含沥青质和重油在热解时可产生大量自由基,如不能被及时稳定和缩聚将转化为大量焦油和气体,形成孔隙结构,从而影响所制冶金焦密度。为此,拟引入添加剂诱导其高效缩聚,提高聚合物密度,再经炭化后制备优质冶金焦。通过系统研究不同添加剂(糠醛、甲醇、呋喃和羟基丙酮)、温度(350、400、450、500和550℃)、停留时间(0、30、60和120 min)和添加量(0、4、8和16 g)对所制聚合物缩聚率、结构性质、密度、热稳定性和表面性质影响,获得煤液化残渣诱导缩聚的最优试验条件。在最优条件下,分别探讨所制聚合物和炭化物的表面形貌、微晶结构和元素变化情况,获得煤液化残渣诱导缩聚机理。结果表明,添加剂(糠醛)的诱导缩聚效果最佳,其次是羟基丙酮,因而理想添加剂至少应含有1个醛基或酮基。不同添加剂可促进煤液化残渣缩聚,提高所制聚合物比表面积、孔容、平均孔径和真密度。温度和停留时间对煤液化残渣/糠醛聚合物热稳定性和表面性质影响较大,温度升高和停留时间延长可促进煤液化残渣所含酚类基团和芳香物中H参与缩聚反应,提高聚合物的缩聚程度。煤液化残渣/糠醛(焦炭)整体呈片层密实状,并含更多无定形碳。

煤液化固渣萃余物的组成结构及铁催化剂活性相回收

为解决大规模煤直接液化催化剂铁源供应问题,同时实现煤液化固渣萃余物的无害化分质利用,从固渣萃余物中回收铁催化剂的角度进行研究,探索采用物理磁选法进行铁催化剂富集回收的可行性。首先采用粒度分析、XRF、XRD、SEM、TG、SEM-EDX等表征手段对固渣萃余物进行全面的物化性质表征,确定铁催化剂的质量分数和存在形态。由分析可知,工业装置固渣萃余物主要由未反应煤中的炭及残炭、挥发分及灰分组成,其粒度均匀且没有团聚,其中铁元素质量分数为5.96%,铁物种仍以具有顺磁性的Fe1-xS活性相存在,被未反应煤、残余沥青掺杂、包裹,与各种元素Ca、Si、Al、O等均匀混杂分布在萃余物中。在此基础上,选用4种型式的磁选设备在不同磁场强度下进行磁选富集,并将富集后的样品作为催化剂用于煤直接液化反应,考察其直接液化反应性能。试验结果表明,湿式立环脉动高梯度磁选机一方面将所产生的高梯度磁场力作用于磁性催化剂细粉,同时脉动流体力在一定程度上消除了非磁性颗粒的机械夹杂。在清水作为分散介质及洗涤介质下,更有效地实现了固渣萃余物中铁催化剂细粉的精细分离。在640000 A/m外加磁场强度下,含铁催化剂物料富集率为10.48%,铁元素质量分数可达11.37%,高压釜萃取油产率为41.96%,与无催化剂时相比高7.17%,比固渣萃余物提高8.99%,可掺混至新鲜催化剂中实现有效回用,部分解决催化剂铁源短缺的问题。

煤直接液化油渣萃余物组成、性质分析及应用场景探讨

煤直接液化油渣用洗油萃取后再经离心分离、常减压闪蒸等工艺处理,分离沥青质后可得到不同等级的沥青产品以及萃余物,将萃余物大规模利用,可以大大提高企业的经济效益。分析了萃余物的族组成、性质,在此基础上讨论了萃余物应用于配煤气化、循环流化床锅炉掺烧、炭灰分离的可行性。分析认为:萃余物更适合通过配入原料煤应用于干粉煤气化。

氯苯添加量对通用级碳纤维结构与强度性能的影响

采用氯化-脱氯化法制备通用级碳纤维是煤液化残渣的高附加值利用路径之一,然而迄今为止,针对以氯苯为氯源诱导的氯化-脱氯化反应的研究尚不够深入,尤其是氯苯添加量对碳纤维结构与性能的影响仍缺乏研究。以煤液化残渣为原料,以氯苯为氯源,采用氯化-脱氯化法制备通用级碳纤维。借助元素分析仪、傅立叶变换红外光谱仪、^(13)C固态核磁共振波谱仪、X射线光电子能谱仪、基质辅助激光解吸飞行时间质谱仪、扫描电子显微镜、拉伸强度测试仪及高精度显微镜表征研究氯苯添加量(10 g~40 g)对沥青前驱体分子组成与结构、熔融纺丝性及碳纤维强度性能的影响及规律。结果表明:经氯化-脱氯化法制得的煤液化残渣基沥青前驱体以芳香碳为主要组成,碳元素含量达91%以上,且碳元素含量和碳氢质量比随着氯苯添加量的升高而略微降低;X射线光电子能谱分析结果表明,经脱氯化反应后未见氯元素残留;氯化-脱氯化反应促使了芳环之间的缩聚,当氯苯添加量为20 g时,平均相对分子质量的质荷比为677;通过13 C固态核磁共振波谱可知,氯苯诱导的缩聚反应主要是加强了芳环的渺位缩聚,当氯苯添加量从10 g增加至40 g时,渺位缩聚碳的含量从9.40%提升至11.78%,这说明沥青前驱体的分子结构沿着一维方向呈现线性排列,进而熔融纺丝性随着氯苯添加量的增加而明显提高,CLR-CB-30和CLR-CB-40两组沥青前驱体在293 r/min的缠丝转速下仍能实现连续纺丝而不发生断裂,碳纤维的表面和断面光滑无缺陷,平均强度性能最高达932 MPa,平均直径约为12μm。表明采用氯化-脱氯化法制备出的煤液化残渣基通用级碳纤维具有较好的强度性能,达到了目前以煤焦油沥青或者石油沥青为原料工业化生产的通用级碳纤维的水平。

Investigation of Solvent Extraction with GC/MS and Residue with TG-FTIR from High-Temperature Coal Tar

A high-temperature coal tar （HTCT） was sequentially extracted with petroleum ether （PE）, ethyl acetate （EA）, and acetone with ultrasonic irradiation to afford extracts 1 to 3 （El to E3）, respectively, and acetone residue. The gas chromatography/mass spectrometry （GC/MS） analysis of all extracts show that E1 is mainly composed of diand tricyclic arenes such as naphthalenes, phenan- threne, anthracene, etc., whereas high contents of heteroatomic compounds and four or more ring arenes were found in E2 and E3, respectively. The pyrolysis process of acetone residue was studied with a thermogravimetric （TG） analyzer equipped with Fourier transform infrared （FTIR） spectrometer. The results indicate that volatiles were mainly released at 380-560 ℃, and the maximum mass loss rate occurred at 492 ℃.

基于高效解离-选择性絮凝耦合作用的煤气化渣提炭实验研究

煤气化渣是由煤气化工艺产生的一种富含铝硅酸盐、灰组分及残炭的大宗工业固体废弃物,其规模化生产对生态环境造成了严重的影响。因此,将煤气化渣进行炭-灰分离是实现其减量化、无害化和资源化利用的关键。以煤气化渣为研究对象,采用高效解离-选择性絮凝耦合作用的工艺,为实现煤气化渣更为合理、高效的资源化利用,减少煤气化渣带来的土壤、空气、水体资源等污染问题,对煤气化渣进行提炭实验研究。首先分析了煤气化渣的理化性质,其次采用单因素变量法探究了磨矿时间、pH、絮凝剂种类、絮凝剂用量、高速剪切转速对煤气化渣提炭实验的影响,以实现残余炭产品的高度富集。结果表明:原煤气化渣灰分质量分数为67.19%,普通湿筛筛上物料灰分质量分数为54.3%,当煤气化渣磨矿时间为5 s, pH为7,絮凝剂聚氧化乙烯用量为0.4 kg/t,在转速为4 000 r/min高速剪切15 min的条件下提炭效果最佳,最终可获得产率为26.6%、湿筛筛上灰分质量分数为43.3%的残炭产品。对比普通湿筛法,基于高效解离-选择性絮凝实验方法在普通湿筛的基础上灰分质量分数降低了11%,降灰效果明显。

煤直接液化残渣复合改性沥青胶浆的流变特性

为探究煤直接液化残渣(DCLR)复合改性沥青胶浆的流变特性,针对3种沥青胶浆(DCLR复合改性沥青胶浆、DCLR改性沥青胶浆和SK-90沥青胶浆)设计了4种粉胶比.采用动态剪切流变(DSR)试验、弯曲梁流变(BBR)试验、差示扫描量热(DSC)试验和扫描电镜(SEM)试验对沥青胶浆的流变特性进行探究.结果表明:DCLR复合改性沥青胶浆的耐热性较好,热稳定性较强,高温抗流动变形能力显著强于SK-90沥青胶浆;DCLR复合改性沥青胶浆的温度敏感性显著下降,低温流变性显著强于DCLR改性沥青胶浆;相比SK-90沥青胶浆和DCLR改性沥青胶浆,DCLR复合改性沥青胶浆的综合高低温性能最优.

煤基费托合成含蜡滤渣中重质蜡的萃取分离研究

研究煤基费托合成装置中含蜡滤渣的综合利用,在资源利用、经济效益及环保等方面均具有重要意义。以国能宁煤费托加氢精制一线油为萃取剂,采用萃取-离心分离技术,进行了高效回收煤基费托合成含蜡滤渣中重质蜡的研究。通过控制单一变量法,系统考察了渣剂比、萃取温度、离心机转速、离心温度和离心时间对蜡回收率和油损耗率的影响。实验结果表明:在渣剂比1:5、萃取温度80℃、离心机转速3500 r/min、离心温度80℃、离心时间5 min的条件下,蜡回收率稳定在91%~94%之间,油损耗率稳定在15%~18%之间,具有良好的萃取分离效果和技术经济可行性。

粉胶比对煤直接液化残渣复合改性沥青胶浆及混合料低温性能的影响

本工作旨在探究粉胶比对煤直接液化残渣(Direct coal liquefaction residue,DCLR)复合改性沥青胶浆及混合料低温性能的影响。设计了四种粉胶比(0.6、0.8、1.0、1.2)下三种沥青胶浆及混合料(SK-90沥青胶浆及混合料、DCLR改性沥青胶浆及混合料、DCLR复合改性沥青胶浆及混合料),采用弯曲蠕变劲度(BBR)试验、低温小梁试验、半圆弯曲(SCB)试验、接触角试验进行性能评价。试验结果表明:相比于DCLR改性沥青胶浆及混合料,DCLR复合改性沥青胶浆临界破坏温度显著降低,混合料破坏应变提升较大,基本上达到SK-90沥青胶浆及混合料的低温性能水平。综合各种试验结果,三种混合料粉胶比为1.0时的低温性能最优。尤其是DCLR复合改性沥青混合料在粉胶比为1.0时,表现出更好的低温应力松弛能力,较强的抗开裂能力与抗裂缝发展能力。但其受粉胶比变化敏感性较强,当粉胶比增加到1.2时,混合料低温抗开裂能力与抗裂缝发展能力显著降低。

神华煤直接液化残渣理化特性与分子结构特征研究

煤液化残渣制备高端炭材料是目前煤直接液化技术领域研究的热点,该过程实现的关键在于煤液化残渣的深度脱灰,而深度脱灰工艺技术开发需要对液化残渣理化特性与分子结构有深入的认识。以神华煤液化残渣为研究对象,借助TG-DTG探究了液化残渣的失重特性;借助激光粒度仪和透射电镜(TEM)分别研究了液化残渣在洗油和四氢呋喃两种溶剂中的粒度分布特性和颗粒形貌特征;在正负离子(±ESI)和正离子大气压光电离(+APPI)模式下,利用傅里叶变换离子回旋共振质谱仪(FT-ICR MS)对液化残渣的分子结构组成进行了鉴别。研究结果表明:液化残渣的主要失重温区为300℃~600℃,466℃时失重速率最大,此时的活性最高;液化残渣在洗油或四氢呋喃中的粒度呈现百纳米级正态分布,残渣在洗油中粒度分布更为集中且粒径更小;液化残渣中含丰富的N1、N2类含氮杂环以及O1、O2、O3、CH类含氧多环的芳香分子构型。

煤直接液化残渣催化热解过程中官能团演变特性研究

采用原位红外催化反应装置,利用傅里叶变换红外光谱仪(FT-IR),以CaCl_(2)·6H_(2)O、FeCl_(3)·6H_(2)O和Cs_(2)SO_(4)为催化剂,对比分析了添加3种不同催化剂以及不同含量的Fe^(3+)在煤直接液化残渣(DCLR)催化热解过程中官能团的演变特性。结果表明:3种催化剂一定程度上都促进了DCLR的缩聚反应;对于以FeCl_(3)·6H_(2)O为催化剂的样品,当热解温度为500℃左右时苯骨架结构峰位由1546 cm^(-1)向1600 cm^(-1)偏移,表明DCLR内的缩聚反应大于分解反应,其芳香骨架结构缩聚程度提高,稠环体系变大;对比不同浓度FeCl_(3)·6H_(2)O在升温过程中对脂肪侧链甲基和亚甲基在热解过程中的催化效果,发现Fe^(3+)在DCLR热解过程中对脂肪族甲基的脱除起到了抑制作用,且随着样品中Fe^(3+)含量的增加(在质量分数为1%~10%时),其抑制作用越强。

部分脱灰及碱金属对煤直接液化渣热化学过程的影响

以煤直接液化渣为原料,利用热重分析仪,考察了部分脱灰和碱金属对其在水蒸气气氛下热化学过程的影响,并计算了气化阶段的表观活化能。结果表明:部分脱灰提高了煤直接液化渣在热解和气化阶段的转化率,降低了半焦的表观活化能,对热化学过程产生积极的影响;NaCl在热解和气化过程中均未表现出明显的催化作用;KCl在热解过程中同样没有表现出明显的催化作用,在气化阶段,则提高了半焦在低温下的气化转化率,表现出了催化作用,并使半焦的气化反应进入到了内扩散过渡区。