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能源强国目标下煤炭安全保供及高效降碳效力研究

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中国工程科学 2024年第4期26卷 40-51页

作者：葛世荣刘淑琴刘金昌王兵安小雅向玲中国矿业大学(北京)机械与电气工程学院北京100083 中国矿业大学(北京)化学与环境工程学院北京100083 中国矿业大学(北京)能源与矿业学院北京100083

煤炭安全保供及高效降碳效力研究可为能源强国目标下煤炭领域发展规划提供有力的决策支撑。本文从安全保供和高效降碳两个角度入手,研究了煤炭在能源强国目标下继续保持主体能源地位的潜力、能力和实力,着重通过构建煤炭安全保供的系统... 详细信息

煤炭安全保供及高效降碳效力研究可为能源强国目标下煤炭领域发展规划提供有力的决策支撑。本文从安全保供和高效降碳两个角度入手,研究了煤炭在能源强国目标下继续保持主体能源地位的潜力、能力和实力,着重通过构建煤炭安全保供的系统动力学模型预测了煤炭安全保供的效力,分析了2060年前煤炭领域的降碳效力。研究结果表明:我国煤炭的可采储量和资源分布是安全保供的基本保障,结合近20年煤炭供应和消费关系可知,我国煤炭资源具备稳定、安全、坚实的保供能力;未来煤炭的安全保供效力在波动中逐渐趋向于动态的柔性平衡;传统煤炭能源向煤基能源过渡效力是构建能源强国目标下新型能源体系的重要环节。我国煤炭领域在清洁转化与利用中体现出显著的降碳潜力,未来随着煤炭地下气化和富油煤开发利用等技术的发展应用将展现出较强的降碳效力,至2060年总体的降碳效力约为1×10^(9)t。

关键词：能源强国煤炭领域安全保供高效降碳效力预测

氯苯添加量对通用级碳纤维结构与强度性能的影响

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煤炭转化 2024年第3期47卷 83-91页

作者：刘金昌向玲严作贤王欣雨梁鼎成解强中国矿业大学(北京)化学与环境工程学院北京100083

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... 详细信息

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。

关键词：通用级碳纤维煤液化残渣氯化-脱氯化氯苯添加量结构强度性能

Accelerating local SGD for non-IID data using variance reduction

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Frontiers of Computer Science 2023年第2期17卷 73-89页

作者： Xianfeng LIANG Shuheng SHEN Enhong CHEN jinchang liu Qi liu Yifei CHENG Zhen PAN Anhui Province Key Laboratory of Big Data Analysis and Application University of Science and Technology of ChinaHefei 230027China Ant Financial Services Group Hangzhou 310000China Department of Computer Science and Engineering Hong Kong University of Science and TechnologyHong Kong 999077China

Distributed stochastic gradient descent and its variants have been widely adopted in the training of machine learning models,which apply multiple workers in *** them,local-based algorithms,including Local SGD and FedAvg,have gained much attention due to their superior properties,such as low communication cost and ***,when the data distribution on workers is non-identical,local-based algorithms would encounter a significant degradation in the convergence *** this paper,we propose Variance Reduced Local SGD(VRL-SGD)to deal with the heterogeneous *** extra communication cost,VRL-SGD can reduce the gradient variance among workers caused by the heterogeneous data,and thus it prevents local-based algorithms from slow convergence ***,we present VRL-SGD-W with an effectivewarm-up mechanism for the scenarios,where the data among workers are quite *** from eliminating the impact of such heterogeneous data,we theoretically prove that VRL-SGD achieves a linear iteration speedup with lower communication complexity even if workers access non-identical *** conduct experiments on three machine learning *** experimental results demonstrate that VRL-SGD performs impressively better than Local SGD for the heterogeneous data and VRL-SGD-W is much robust under high data variance among workers.

关键词： distributed optimization variance reduction local SGD federated learning non-IID data

Flexibility analysis and design of heat exchanger network for syngas-to-methanol process

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International Journal of Coal Science & Technology 2021年第6期8卷 1468-1478页

作者： jinchang liu Pingping Zhang Qiang Xie Dingcheng Liang Lei Bai School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)D11 Xueyuan RoadHaidian DistrictBeijing 100083China Department of Chemical and Biomedical Engineering West Virginia University395 Evansdale DrivePO Box 6102MorgantownWV 26506-6102USA

The heat exchanger network(HEN)in a syngas-to-methanol process was designed and optimized based on pinch technology under stable operating conditions to balance the energy consumption and economic *** actual industrial processes,fluctuations in production inevitably affect the stable operation of HENs.A flexibility analysis of the HEN was carried out to minimize such disturbances using the downstream paths *** results show that two-third of the downstream paths cannot meet flexibility requirements,indicating that the HEN does not have enough flexibility to accommodate the disturbances in actual production.A flexible HEN was then designed with the method of dividing and subsequent merging of streams,which led to 13.89%and 20.82%reductions in energy consumption and total cost,*** to the sufficient area margin and additional alternative heat exchangers,the flexible HEN was able to resist interference and maintain production stability and safety,with the total cost increasing by just 4.08%.

关键词： Heat exchanger network Syngas-to-methanol Pinch technology Flexibility analysis Design Optimization

Preparation of pitch precursor with excellent spinnability for general-purpose carbon fibre using coal tar pitch as raw material

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Chinese Journal of Chemical Engineering 2023年第2期54卷 22-28页

作者： jinchang liu Chenyang Shen Lujie Huang Tinghao Fang Yaping Li Dingcheng Liang Qiang Xie School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Tetrahydrofuran(THF) extract of coal tar pitch(CTP) was used instead of blending CTP with pretreated pyrolysis fuel oil to prepare an isotropic pitch precursor with excellent spinnability for general-purpose carbon fibre through bromination-dehydrobromination. The feasibility and effectiveness of synthesising an isotropic pitch precursor derived from THF-soluble(CTP-THFs) is demonstrated in this *** results show that CTP-THFs contains more light components than CTP;CTP-THFs and CTP monomer proportions were 62.52% and 45.32%, respectively. However, based on comparisons of CTP-THFsBr0 and CTPBr0 characterisations, CTP-THFs exhibits better polycondensation than CTP. Bromination-dehydrobro mination promotes polycondensation of pitch precursors, leading to greater carbon aromaticity in CTP-THFsBr5, CTP-THFsBr10, and CTP-THFsBr15 than that in CTP-THFsBr0 and CTPBr0. CTP-THFsBr5 and CTP-THFsBr10 have excellent spinnability even with softening points as high as 230 ℃. The pericondensed carbon and carbon aromaticity of CTP-THFsBr5 and CTP-THFsBr10 are high owing to the higher degree of polycondensation;however, they still possess a more linear molecular structure. The as-prepared carbon fibre exhibits homogeneity and uniformity, and the mechanical performance is comparable with that of commercial general-purpose carbon fibre products.

关键词： Carbon fibre Isotropic pitch Coal tar pitch(CTP) High spinnability Bromination–dehydrobromination

Preparation and modification of activated carbon for benzene adsorption by steam activation in the presence of KOH

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International Journal of Mining Science and Technology 2013年第3期23卷 395-401页

作者： Yao Xin liu jinchang Gong Guozhuo Jiang Yu Xie Qiang School of Chemical and Environmental Engineering China University of Mining & Technology Beijing Institute of Labor Protection Science Datong Coal Mine Group Company

A series of activated carbons from Taixi anthracite were prepared by steam activation in the presence of KOH and then they were modified by different methods. The regulation of porosity and the modification of surface chemistry were carried out with the aim to improve the benzene adsorption capacity of activated carbon. The influences of KOH and activation process parameters including activation temperature, activation time and steam flow rate on porosity of activated carbon were evaluated, and the effect of modification methods on surface chemistry was investigated. Also, the relationship between benzene adsorption capacity and porosity and surface chemistry was analyzed. Results show that activation temperature is the dominant factor in the activation process; the introduction of KOH into the raw material can enhance the reactivity of char in activation process, meanwhile it shows a negative effect on the porosity development, especially on the mesopore development. Results of FTIR analysis indicate that anthracite-based activated carbon with condensed aromatics and chemically inert oxygen does not present the nature to be surface modified. Besides, benzene adsorption capacity has an approximate linear relationship with surface area and in our preparation, benzene adsorption capacity and surface area of activated carbon are up to 1210 m 2 /g and 423 mg/g, respectively.

关键词： Activated carbon Steam activation Surface modification Benzene Potassium hydroxide

An analytical transient coal permeability model:Sorption non-equilibrium index-based swelling switch

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1175-1191页

作者： Xingxing liu Jishan liu Liang Chen jinchang Sheng Huimin Wang College of Civil and Transportation Engineering Hohai UniversityNanjing210098China School of Engineering The University of Western Australia35 Stirling HighwayCrawleyWA6009Australia College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China

Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption ***,this sorption swelling switch mechanism has not been considered in current analytical permeability *** study introduces a normalized sorption non-equilibrium index(SNEI)to characterize the sorption status,quantify the dynamical variations of matrix swelling accumulation and internal swelling partition,and formulate the sorption swelling switch *** incorporation of this index into the extended total effective stress concept leads to an analytical transient coal permeability *** results show that the sorption swelling switch itself results in the permeability switch under stress-constrained conditions,while the confined bulk swelling suppresses the permeability recovery to the continuous reduction under displacement-constrained *** verifications show that current experimental observations correspond to the early stages of the transient process,and they could be extended to the whole process with these *** study demonstrates the importance of the sorption swelling switch in determining permeability evolution using simple boundary *** provides new insights into experimentally revealing the sorption swelling switch in the future,and underscores the requirement of a rigorous model for complex coupled processes in large-scale coal seams.

关键词： Coal permeability Sorption swelling switch Sorption non-equilibrium Boundary conditions

地铁施工塌陷的SBAS-InSAR长时序监测与早期识别

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武汉工程大学学报 2024年第1期46卷 105-110页

作者：刘金昌王慧妮徐吟李康伦张华睿刘天鹤武汉工程大学土木工程与建筑学院湖北武汉430074 中铁十一局集团有限公司湖北武汉430061 武汉综合交通研究院有限公司湖北武汉430015

以2019年青岛市沙子口和胜利桥发生的2处地铁施工塌陷事故为研究对象,基于改进的SBASInSAR技术,利用60景Sentinel-1卫星影像数据,获取地面塌陷前后的青岛市的地表形变时序信息,分析了塌陷事故区地面形变过程与塌陷事故的相关性,提出了... 详细信息

以2019年青岛市沙子口和胜利桥发生的2处地铁施工塌陷事故为研究对象,基于改进的SBASInSAR技术,利用60景Sentinel-1卫星影像数据,获取地面塌陷前后的青岛市的地表形变时序信息,分析了塌陷事故区地面形变过程与塌陷事故的相关性,提出了利用合成孔径雷达卫星遥感数据开展城市地铁施工地面塌陷监测预警的方法。通过对沙子口和胜利桥2处事故点的长时间序列地表形变监测数据进行统计分析比较,将累积形变量转化为每日平均沉降速率,提出了用于早期识别地表沉降的指标,即在1个周期(12 d)内,平均沉降速率超过0.02 mm/d,而施工预警阈值为连续观测3个周期,平均沉降速率超过0.02 mm/d。

关键词： SBAS-InSAR 地面塌陷地铁施工形变监测

沥青基碳纤维的制备工艺、反应机理及调控方法

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洁净煤技术 2024年第1期30卷 110-123页

作者：刘金昌严作贤王欣雨解强梁鼎成中国矿业大学(北京)化学与环境工程学院北京100083

沥青基碳纤维是重要的工程碳纤维之一,在航空航天、国防军工等领域具有广泛应用。沥青基碳纤维制备流程长、影响因素多,归咎于对其制备工艺、反应机理及调控方法的认识不足,迄今工业化生产强度性能优异的沥青基碳纤维仍面临诸多困难。... 详细信息

沥青基碳纤维是重要的工程碳纤维之一,在航空航天、国防军工等领域具有广泛应用。沥青基碳纤维制备流程长、影响因素多,归咎于对其制备工艺、反应机理及调控方法的认识不足,迄今工业化生产强度性能优异的沥青基碳纤维仍面临诸多困难。以碳纤维生产流程为主线,针对原料预处理、沥青前驱体调制、熔融纺丝、预氧化及炭化与石墨化的现状、方法、机理及调控进行深入探讨分析。沥青基碳纤维的原料有煤系、石油系、生物质系、高分子系和纯化合物,原料预处理方法主要有蒸馏和萃取;沥青前驱体的调制本质是以氢转移反应和自由基反应并行的液相炭化反应,包括环化、芳构化、低聚和缩聚等复杂的反应过程。芳烃低聚物在高温下缩聚形成稠环芳烃片状大分子的基本结构单元,基本结构单元经过热运动不断聚集,形成聚集体;由于范德华力作用使基本结构单元相互堆叠,形成平行堆积体,进而通过层积、堆积等过程形成基本构筑单元聚集体。基本构筑单元聚集体在不同反应条件下可以转变为长程无序、短程有序的难石墨化结构,也可以转变为长程有序、短程有序的易石墨化结构。以煤系、石油系和生物质系物质为原料调制沥青前驱体时,因其反应活性好,通常选用设备简单、操作容易、成本低廉的热缩聚法;而当以萘、甲基萘等纯化合物为原料时,因其反应活性差,需要较高的温度才能引发自由基反应,故通常采用催化合成法。熔融纺丝宏观上起到塑型的作用,通过改变纺丝参数和喷丝板的形状分别可以调节碳纤维的直径和形状;此外,熔融纺丝对中间相沥青前驱体的重排分子作用尤为明显,使得石墨微晶更易沿轴向一维排列形成有序的石墨晶体结构。为使沥青纤维在炭化过程中不发生融化,需要将沥青纤维由热塑性转变为热固性,即通过轻微的氧化反应,让沥青中的稠环芳烃分子经历氧化、缩合、分解和脱水,从而形成特定的交联结构,最终在纤维结构中生成一定量的含氧官能团。炭化是使预氧化后的纤维经过复杂的化学反应和结构转变形成具有炭材料分子结构特征的碳纤维。炭化过程中,石墨微晶发生重排,非碳原子被移除,碳元素含量进一步升高;经过石墨化后,石墨晶体结构更加完整、取向度更高,使碳纤维向石墨纤维转变,强度性能更加优异。另外,针对沥青基碳纤维的突破方向,提出了从分子维度定向可控制备的思路;并为碳纤维生产过程中耗时耗能的预氧化步骤的优化改进提供了具体方法。

关键词：碳纤维沥青基制备机理调控