2024年11期目次

  • Research progress in highly selective hydrogenation of COx to light olefins

    YANG Qingwei;SUN Zheyi;SHAO Bin;HU Jun;Sinopec Maoming Petrochemical Company;School of Chemistry and Molecular Engineering,East China University of Science and Technology;

    C_2—C_4 olefin(C_2~=—C_4~=) is a major chemical raw material and in a flourishing demand in China.Currently,its manufacturing technique is mostly based on naphtha cracking,which is not in line with the national energy endowment of " rich coal but lean oil".Coal gasification,typically produces syngas(CO/H_2) first,and subsequently to olefin(STO) is considered as a promising technology.Meanwhile,converting CO_2 from industrial flue gas into C_2~=—C_4~= is critical for realizing the "Carbon Neutrality".The direct and highly selective conversion of CO_x(both CO and C_O2) to C_2~=—C_4~= via the metal Oxide-Zeolite(OX-ZEO) route breaks through the limitation of the Anderson-Schulz-Flory distribution of the traditional Fischer-Tropsch synthesis technology,but still suffers from the trade-off between CO_x conversion efficiency and C_2~=—C_4~= yield.Recent development of OX-ZEO bifunctional catalysis strategy for CO_x hydrogenation to light olefins was reviewed,with emphasis on the effects of the type and elemental composition of metal oxides,the acidity and topological structure of zeolite on the catalytic performance.The role of oxygen vacancy and side reaction inhibition strategies on CO_x hydrogenation was clarified.In addition,the reaction mechanism over OX-ZEO was reviewed in detail.With this,insights into significant promising tendencies and confronting challenges in the strategy of OX-ZEO for CO_x to light olefin was suggested.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1453K]

  • Efficient combustion characteristics of converter low-quality gas from steelmaking in cyclone separator

    WANG Ziyi;LI Sen;WEI Xiaolin;ZHAO Jing;LI Bo;YAO Yuan;State Key Laboratory of High Temperature Gas Dynamics,Institute of Mechanics,Chinese Academy of Sciences;School of Engineering Science,University of Chinese Academy of Sciences;

    At the beginning and end of oxygen blowing in converter steelmaking,the converter gas produced is of low quality(low CO concentration with a small amount of O_2),which is explosive and cannot be recycled.At present,the converter low-quality gas is burned unorganized in the gasification cooling stack by entraining air,which is difficult to realize the efficient combustion and utilization of the gas in the gasification cooling device.The characteristics of strong swirl and strong mixing in the cyclone separator are conducive to the mixed combustion of converter low-quality gas while removing dust from converter gas.In order to solve the difficulty in efficient combustion and utilization of converter low-quality gas,based on a new process of converter gas full dry recovery,the flow and combustion of converter low-quality gas in the cyclone separator were studied by CFD.The results show that:the excess air coefficients near the center of gasification cooling stack are lower than 0.4,all the excess air coefficients in the cyclone separator are higher than 1,the converter low-quality gas is fully mixed with air in the cyclone separator;The higher turbulent kinetic energy and local vortex improve the mixing of converter low-quality gas and air in the cyclone separator;The combustion area in the gasification cooling stack is narrow,the average concentration fraction of OH in the flow section is 305×10~(-6),and the combustion intensity is low;The combustion area in the cyclone separator is widely distributed,the average concentration fraction of OH in the flow section reaches 650×10~(-6),and the combustion intensity is high;After the converter low-quality gas flows through the cyclone separator,the combustion efficiency increases from 74.64% to 98.86% in the pre combustion stage,and the combustion efficiency increases from 44.08% to 95.05% in the post combustion stage;The efficient combustion of converter low-quality gas is realized in the cyclone separator.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 4109K]

  • Mechanistic of the effect of differential electron density characteristic groups on the nitrogen migration transformation in coal

    WANG Xin;ZHANG Hai;WANG Kai;FAN Weidong;School of Mechanical and Power Engineering,Shanghai Jiao Tong University;

    The choice of pyrrole-and pyridine-containing nitrogen heterocycles as the subject of this paper was made in,and based on this,the mechanism and pattern of action of the influence of functional groups on the migration and transformation of nitrogen components of coal pyrolysis were studied.First,the CBS-QB3 was used to optimize the paths of pyrrole and pyridine pyrolysis to HCN and NH3,and the corresponding reaction potential energy surfaces were derived.Additionally,the accumulated 112 nitrogen migration conversion pathways of pyrrole and pyridine derivatives were optimized,the functional groups were divided into electron-donating(EDG) and electron-withdrawing groups(EWG),and the summation values of the bond polarity indices of the groups were calculated based on Pauling electronegativity.Finally,12 appropriate descriptors were screened by comparing Pearson correlation coefficients,which were derived from the structures effectively optimized by DFT calculations.By integrating multiple linear regression models,the greatest response activation energy in the coal-nitrogen migration conversion process was predicted,and the MLR model constructed had a coefficient of determination of 0.83,a root mean square error of 0.41 for the training set and a coefficient of determination of 0.92 and a root mean square error of 0.29 for the test set.The model could be used to estimate activation energy since it has high fitting and prediction ability.An in-depth analysis of the multiple linear regression equation of the model reveals that the coefficient of the group type is the largest(0.71),followed by the energy gap of the reactants(0.64) and the difference between the energy gaps of the reactants and products(-0.59),further confirming the significant influence of the group type on the nitrogen migration transformation.The findings of this paper can guide the mechanistic study of coal nitrogen migration conversion and aid in the creation of new ultra-low NO_x combustion technologies.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 2118K]

  • Mechanism of Na on NO reduction by ammonia and char during ammonia-coal co-firing process

    ZHANG Baohua;QU Mingxin;HE Wenjun;PANG Bo;ZHU Hongwei;XU Jingying;XU Yishu;Powerchina Hubei Electric Engineering Co.,Ltd.;School of Energy and Power Engineering,Huazhong University of Science and Technology;State Key Laboratory of Coal Combustion and Low Carbon Utilization,Huazhong University of Science and Technology;

    Coal-fired boilers can realize significant carbon emission reduction by using co-combustion with ammonia which is one of the low-carbon fuels.NO generation and emission in ammonia-coal co-firing is very critical.Ca,Fe,K,Na,and other typical mineral elements in coal have different effects on NO generation and emission during coal combustion and ammonia-coal co-firing.The effects of Ca,Fe and K on NO generation and reduction in coal-ammonia co-firing have been investigated,but the role of Na is still not clear.To investigate the mechanism of NO reduction in the high-temperature oxygen-poor region during ammonia-coal co-firing and the role of the mineral element Na,quantum chemical calculations were carried out.Firstly,the char model for adsorption of Na atom at various positions was constructed using a typical Zigzag model.The calculation results showed that Na atom were more likely to be adsorbed on unsaturated carbon at the edge of the char rather than adsorbed parallel to the char.Next,adsorption energy calculations were carried out for different adsorption orders of NO and NH.The results showed that NO and NH were more stable to adsorbed on both sides of Na atom.Compared to configuration without the participation of Na,the maximum increase in adsorption energy of the configuration with Na participation is-49.31 kJ/mol.Then,the detailed steps of the reaction were explored for six reactant configurations.The migration of H atom to the char surface to form the N_2 molecules showed a significantly lower rate-limiting step energy barrier.Meanwhile,the results showed that the involvement of Na significantly reduced the energy barrier of the rate-limiting step of the reaction by 77.12 kJ/mol(Path5 compared to Path 2).Finally,kinetic calculations of the rate-limiting steps of the six paths were performed.The results showed that the presence of Na promoted the reaction and was more pronounced at low temperatures(4 259-fold for Path 5 compared to Path 2),as well as reduced the temperature dependence of the reaction.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 2202K]

  • Effect of temperatures on emission characteristics of NOx and SO2 for pine shaving under CO2 gasification

    ZHAO Yan;ZHANG Cheng;MA Lun;LI Junchen;FANG Dingli;TAN Peng;FANG Qingyan;CHEN Gang;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

    CO_2 gasification is a novel technique that uses CO_2 as a gasifying agent to produce syngas with a high calorific value for the synergistic utilization of CO_2 and biomass waste.However,the emission characteristics of NO_x and SO_2 for biomass waste under CO_2gasification are rarely investigated.CO_2 gasification experiments were carried out on a fixed bed reactor for pine shaving in order to provide a temperature reference for thermochemical conversion utilization and pollutant emission control of biomass waste.The results show that the yield of CO is 0.24,0.52,and 0.95 m~3/kg at 700,800,and 900 ℃,respectively,significantly higher than the yields of H_2 and CH4.Thus,CO is the major component of the produced syngas.In addition,the carbon conversion yield is 18.36%、36.15%,and 66.09%,respectively,and the CO_2 gasification efficiency is 13.04%,41.59%,and 92.99% at 700-900 ℃,respectively.These phenomena indicate that increasing temperatures can contribute to the thermochemical conversion of pine shaving under CO_2 gasification.Moreover,the peak concentrations and the durations required to reach the peaks of NO in produced syngas are 248,129,and 138 mg/m~3 and 140,195,and320 s,respectively;those for NO_2 are 339,191,and 107 mg/m~3 and 115,150,and 265 s,respectively,and those for SO_2 are 3 299,3 065,and 2 882 mg/m~3 and 130,175,and 180 s,respectively.The peak concentrations of both NO_x and SO_2 gradually decrease and the required durations increase as the temperatures increase,suggesting that the increase in temperature contributes to a reduction in the yields of NO_x and SO_2.However,the conversion yields of NO_x and SO_2 gradually increase as the temperatures increase,reaching 49.73% for NO_x and68.87% for SO_2 at 900℃.This shows that a higher temperature can enhance the oxidation effect of oxygen in raw material and gasifying agent(CO_2) on the sulfur and nitrogen in pine shaving,further promoting the conversion yields of NO_x and SO_2.Furthermore,the conversion yield of NO increases while that of NO_2 decreases with increasing temperatures.The reducing atmosphere in the furnace with CO as the major component contributes to the NO_2 being reduced to NO.Therefore,increasing the temperatures of CO_2 gasification for pine shaving can promote the reduction process of NO_2 by increasing the yield of CO.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 999K]

  • Experimental study of purifying flue gas after wet desulfurization in thermal power 300 MW units by acoustic agglomeration

    WEI Zekun;HUANG Yaji;LIU Yuqing;WANG Sheng;ZHANG Rongchu;DING Xueyu;LI Yuxin;LI Jinlei;ZHANG Xuewei;ZHU Zhicheng;LI Zhiyuan;Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,Southeast University;Changrong Acoustic Limited Liability Company;State Key Laboratory of Clean and Efficient Coal-fired Power Generation and Pollution Control;

    At present,the limestone-gypsum wet desulfurization system is widely used in domestic thermal coal-fired power units,which generates a large amount of particulate matter,and the traditional dust and mist elimination devices have a relatively limited effect on the removal of particulate matter with small particle size,especially PM_(10).Acoustic agglomeration is important for controlling the emission of fine particulate matter,especially PM_(10),and can be used as a pretreatment link for soot in combination with conventional dust and mist eliminators.To solve the problem of fugitive dust,especially PM_(10),in the flue gas of thermal power units after wet desulfurization,engineering modification tests are conducted on the flue,configured with different combinations of 3 200,1 600 and 800 Hz frequencies to investigate their effects on PM_(10) quantity concentration and particle size distribution,and the combination of acoustic waves with the best agglomeration effect was selected.The dust removal efficiency is tested under background conditions,acoustic wave alone,and acoustic wave coupled with spray.The results show that the number concentration of PM_(10) is higher when the acoustic wave is not turned on,which is 2.75×10~4 cm~(-3),and the peak particle size is about 0.05 μm.The number concentration of PM_(10) decreases significantly after the acoustic wave is turned on,the peak particle size increases,and the number concentration of PM_(10) is the lowest in the combination of3 200 Hz×4+1 600 Hz×2,which is 2.26×10~4 cm~(-3).This number represents the highest agglomeration efficiency of 17.82%.In the test of dust removal efficiency,the dust removal efficiency is low when the mist eliminator acts alone,only 34.3%,with the above-mentioned acoustic waves,the dust removal efficiency increases to 52.1%,and then the highest dust removal efficiency is achieved when the auxiliary spray is used,reaching 60.4%,at which time the dust concentration at the outlet of the mist eliminator drops to below 5 mg/m~3,meeting the ultra-low emission requirements.In addition,for the low concentration PM_(10) environment in the test,the acoustic wave agglomeration law is still applicable,but the particle collision probability is low,which can be compensated by a combination of high and low frequency acoustic wave.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1327K]

  • Carbon residue prediction of coal combustion in circulating fluidized bed boiler based on particle tracer

    MA Zhangke;CHENG Leming;LI Liyao;ZHANG Weiguo;GUO Qiang;State Key Laboratory of Clean Energy Utilization,Institute for Thermal Power Engineering,Zhejiang University;Jiaxing Research Institute,Zhejiang University;Dongfang Boiler Group Co.Ltd.;

    The carbon residue is essential for reflecting the combustion efficiency of CFB boiler,the accurate prediction of carbon residue has significance for CFB operation and design.Based on the trajectory and residence time of particles in the furnace,the carbon content of coal particles out of the furnace was calculated.The effects of residence time,furnace temperature,coal rank,and excess air ratio were investigated.It is found that the coal particle with longer residence time has lower carbon content.When the bed temperature increases from 800℃ to 900 ℃,the carbon residue decreases by about 40%-50%.Increasing the excess air ratio from1.05 to 1.3,the carbon residue reduces by 10%-30%.The rank of coal is the key factor to carbon residue.The volatile,fixed carbon content and reactivity of coal determine the burnout behavior.By comparing the calculated results by the CFB design method and the experimental data,it is proved that the prediction of residual carbon based on the trajectory method is reasonable.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1021K]

  • Denitration performance of catalytic filter bag and synergistic purification of waste incineration flue gas

    DING Delong;WU Zhepeng;GE Chunliang;MA Rushuang;ZHANG Yiqin;WEI Tingfan;HU Daqing;YANG Jianguo;Zhejiang Tiandi Environmental Protection Technology Co.,Ltd.;State Key Laboratory of Clean Energy Utilization,Zhejiang University;Jiaxing Research Institute of Zhejiang University;

    Aiming at the technical idea of catalytic filter bag for synergistic purification of waste incineration flue gas deacidification,denitration and dedust,a synergistic purification experimental system was established.The effects of key factors on the denitration performance of catalytic filter bag were studied under the premise of waste incineration flue gas deacidification.Then the optimized parameters were selected to carry out the synergistic purification experiments.The results show that the denitration efficiency changes by about 15% within the applicable temperature range of 180-220 ℃.The ammonia escape decreases by about 0.9 μL/L for every 10 ℃increase.At 150 ℃,both denitration efficiency and ammonia escape concentration deviate seriously from the demand value.With the increase of ammonia nitrogen ratio 0.1 mol/mol,flue gas moisture content 5%,inlet NO_x concentration 100 mg/m~3 and filtration velocity0.1 m/min,the variation of denitration efficiency is about 4.1%,-2.6%,2.7% and-1.7% respectively,and the variation of ammonia escape concentration is about 1.9,0.5,2.3 and 0.6 μL/L respectively.In the synergistic purification experiments of deacidification and denitration,when the stoichiometric ratio of NaHCO_3 to HCl+SO_2 was 1.1 mol/mol,the removal efficiency of HCl was basically stable at about 96%,and the removal efficiency of SO_2 reached more than 97% and increased slightly with the increase of NH_3/NO.When the NH_3/NO is above1 mol/mol,the denitration efficiency can reach more than 70%.For every 0.1 mol/mol increase in NH_3/NO,the denitration efficiency increases by about 3.2%,and the ammonia escape concentration increases by about 3.1 μL/L.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1140K]

  • Investigation of arsenic resistance of plate-type De-NOx catalyst

    YUE Yanwei;HUANG Li;WANG Suqin;ZONG Yuhao;WANG Hu;LI Jinke;HAN Pei;XIE Xingxing;MA Luoning;GAO Yibo;Datang Nanjing Environmental Protection Technology Co.,Ltd.;Jiangsu JITRI-Topsoe Institute of Advanced Catalytic Technology;Jiangsu JITRI-Topsoe Clean Energy R&D Co.,Ltd.;Instrumental Analysis Center,Inner Mongolia University of Science & Technology;

    Selective catalytic reduction(SCR) is currently the most widely used flue gas denitrification technology,with the core method SCR denitrification catalyst.The presence of the As element in coal combustion fly ash can cause catalyst poisoning and a significant decrease in service life,affecting the stable and efficient operation of the SCR system.V-Mo/Ti catalysts with different mass fractions of MoO_3(3% and 7%) were prepared,in order to improve the As resistance of V-Mo/Ti catalyst.The As poisoned catalysts were also prepared by wet impregnation method.The physiochemical properties of the fresh and As-poisoned catalysts were characterized by XRF,ICP,XRD,N_2-physisorption,H_2-TPR,XPS,NH_3-TPD,and O_2-TPD.The NO_x conversion and N_2O concentration of the different catalysts in the temperature range 230-410 ℃ were tested via a micro fixed-bed reactor.The results show that As has negative influences on the pore structure of the catalyst,and reduces the specific surface area,pore volume,reducibility,acidity,and the amount of O_α of the catalyst.As a result,the catalytic activity of the catalyst declines and the generation of by-product N_2O promotes.With the increase of MoO_3 content,the pore structure of catalyst is improved,the decrease in specific surface area and pore volume is reduced,the reduction performance and surface acid content are increased,and the denitrification activity of catalyst is increased.High mass fraction of MoO_3(7%) can reduce the poisoning effect of As on the V-Mo/Ti catalyst.The catalytic performance of V-Mo(7)/Ti-As catalyst is obviously higher than that of the V-Mo(3)/Ti-As catalyst.In the other word,the As resistance of V-Mo(7)/Ti catalyst is superior to that of the V-Mo(3)/Ti catalyst.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1154K]

  • Development progress of chemical absorbents for carbon dioxide chemical absorption from flue gas of coal-fired power plants

    HE Xuefeng;FAN Hao;SHEN Zhenxing;CHANG Tian;PENG Qin;SONG Bo;School of Energy and Power Engineering,Xi'an Jiaotong University;School of Environmental Science and Engineering,Shaanxi University of Science and Technology;

    According to the sequence of research and development of chemical absorbers,the technical characteristics and performance differences of single amine absorbers,mixed amine absorbers,biphasic absorbers,non-aqueous absorbers and ionic liquids are summarized,and the progress of post-combustion chemical absorption capture technology is introduced with specific cases.To address the problem of high energy consumption in the regeneration of traditional single amine absorbers,solid acid catalysts,some amino acids and derivatives or some metal ions are often used to assist the regeneration process to reduce energy consumption.Mixed amine absorbents combine different ratios of primary,secondary,tertiary or site-resistant amines with different advantages to enhance the performance.Biphasic absorbents reduce regeneration energy by regenerating only the rich liquid phase after absorption.In industrial applications,2-amino-2-methyl-1-propanol(AMP) is commonly used to reduce viscosity,and polyethylene glycol dimethyl ether(NHD) or sulfoxide is used to promote phase separation.Non-aqueous absorbers use physical solvents instead of traditional water to reduce the water content and thus the regeneration energy consumption.Commonly used physical solvents are mainly alcohols and their derivatives.In addition,functionalized ionic liquids with better CO_2 absorption performance are made by introducing primary amine groups into conventional ionic liquids.Ethylene glycol(EG),n-propanol,Monoethanolamine(ME A),N-methyl diethanolamine(MDEA),etc.and some functional ionic liquids can reduce viscosity and regeneration heat.However,the current absorbers also have problems such as high energy consumption,easy degradation and escape of absorber amine.There is an urgent need to develop chemical absorbents with low energy consumption,low loss,low cost and good absorption performance to realize the large-scale application of flue gas CO_2 capture technology.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1330K]

  • CO2 reduction to syngas by CuGa2 electrocatalysis

    ZHANG Junfeng;WEI Shuzhou;WANG Chang;QU Tongxin;XIONG Zhuo;ZHANG Junying;ZHAO Yongchun;SanHe Power Plant Ltd.,CHN Energy;National Energy Research and Development Center of Carbon Capture,Utilization and Storage (CCUS) Technology for Coal-based Energy;Hebei Province Coal-fired Power Station Pollution Prevention and Control Technology Innovation Center;State Key Laboratory of Coal Combustion,Huazhong University of Science and Technology;

    Achieving carbon peak and carbon neutrality is a critical strategic requirement for China's green and sustainable development.Syngas,as a vital raw material for modern chemkal production,traditionally relies heavily on fossil fuels for its preparation,resulting in significant greenhouse gas emissions.In recent years,the technology of electrocatalytic CO_2 reduction to syngas driven by renewable electricity has emerged as an environmentally friendly and sustainable alternative,garnering extensive research interest.While previous studies have explored the impact of different catalysts on the V(H_2)/V(CO) ratio in syngas produced via electrocatalytic CO_2 reduction;effectively tuning the selectivity of H_2 and CO using a single catalyst remains a challenge.To achieve selective modulation of the V(H_2)/V(CO) ratio in syngas products with a single catalyst,this study synthesized CuGa_2 intermetallic compounds through a high-temperature solid-state synthesis process.These compounds were employed as electrocatalysts to enable high selectivity and tunability in the electrocatalytic CO_2 reduction to syngas.A range of characterization techniques,including SEM,EDS,XRD,and XPS,were used to investigate the physicochemical properties and electrochemical performance of the CuGa_2 intermetallics,as well as their catalytic mechanisms during the electrocatalytic CO2 reduction process.The results indicated that this catalyst,consisting of a mixture of CuGa_2and a small amount of metal oxides,could significantly adjust its selectivity for the electrocatalytic CO_2 reduction reaction(eCO_2RR)and the hydrogen evolution reaction(HER) by varying electrolyte concentration and pH,thereby modulating the V(H_2)/V(CO) ratio in the syngas produced.Moreover,tests examining the impact of different applied potentials on the V(H_2)/V(CO) ratio demonstrated that controlling the applied potential allows for the adjustment of active site utilization in the CuGa_2 catalyst,thus altering the selectivity of both eCO2RR and HER.This enables the V(H_2)/V(CO) ratio in syngas products to be tuned within a range of 0.3 to 4.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1394K]

  • Performance of tidal hydrogenotrophic methanation and its feasibility for regenerating CO2-loaded solutions

    MIAO Jiahui;WANG Jiancheng;DAI Yanan;XU Heng;ZHANG Jiayin;ZHAO Minnan;School of Chemical and Environmental Engineering,China University of Mining & Technology-Beijing;Binzhou Institute of Technology;

    To counteract global warming and reach the "double carbon" target,carbon capture,conversion,and utilization(CCCU)is a crucial technical strategy.One of the most recognizable carbon capture techniques,chemical absorption requires a lot of energy to regenerate CO_2-loaded solutions.Bio-regeneration of CO_2-loaded solutions using hydrogenotrophic methanation was proposed here for reducing carbon capture costs.In this method,a solution with a pH of 10 was prepared with Na_2CO_3 and microbial nutrient solutions as CO_2 absorbents,and hydrogenotrophic methanation was used to convert CO_2 to CH_4 so that the solution could be regenerated and the absorbent reused.Initially,a tidal hydrogenotrophic methanation reactor was developed in order to increase the rate of CO_2bioconversion.Its viability for bio-regeneration of CO_2-loaded solutions was determined after examining its startup performance.The results showed that on day 33,the gas residence time(GRT) of the tidal hydrogenotrophic methanation reactor had reached 23 minutes and the CH_4 content at the reactor outlet was about 95%,indicating a CO_2 conversion rate about 10 times higher than that of the conventional trickling bed and fixed bed.During the start-up phase,pH and alkalinity were essentially stable,there was no obvious accumulation of organic acids,and the average total organic acid concentration ranged from 0.2 to 2.3 mmol/L.In the subsequent 5 cycles of CO_2-loaded solution bio-regeneration experiments,the regenerated absorbent's mean CO_2 uptake was 55 mmol/L with a standard deviation of 1.1 mmol/L.The pH of the regenerated absorbent remained stable at 9.53±0.05,indicating that a CO_2-loaded solution based on hydrogenotrophic methanation could effectively recycle absorbent.In the reactor,the relative abundance of the alkali-tolerant bacterial genera Proteiniborus and Acinetobacter and the archaeon Methanobacterium increased after the CO_2-loaded solution bio-regeneration experiment.Results indicate that microorganisms have progressively adapted to weakly alkaline environments by reorganizing their communities to conduct metabolic processes such as CO_2 methanation.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1008K]

  • Preparation and slurry ability of coal water slurry with hydrothermal carbonization pretreatment of corn straw

    ZHANG Yiwen;DING Lu;YANG Mingming;CHENG Chen;YU Guangsuo;Institute of Clean Coal Technology,East China University of Science and Technology;State Key Laboratory of Highefficiency Utilization of Coal and Green Chemical Engineering,Ningxia University;

    Due to the high yield and low utilization of corn straw in China,hydrothermal carbonization(HTC) pretreatment of corn straw with coal was studied to prepare hydrochar coal water slurries(HC-CWS).Using corn straw as raw material,the hydrochar(HC) was prepared by HTC at temperature of 180,200,220,240 ℃ and time of 60 min.The results showed that HTC is a process of dehydration and deoxygenation.The yield and energy yield of HC decreased with increasing temperature.HTC resulted in the appearance of many microsphere particles on the surface of HC,which also led to the enlargement of the pore structure of HC.Mixing HTC-220 and ShenHua coal(SH),the effects of second liquid modification method and dosage and relative humidity on the slurry ability of HC-CWS was studied.The results showed that the HC-CSW had the lowest apparent viscosity and the beat fluidity when the kerosene was modified with HC.When the kerosene dosage was 0.8%,the HC-CWS had the lowest apparent viscosity and the apparent viscosity was 979.5 mPa·s.The apparent viscosity of HC-CWS decreased with the increase of relative humidity.This was due to the water molecules like "bottle stoppers" to prevent pores from being filled with water,which increased the content of free water in the HC-CWS and improved the slurry performance.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1407K]

  • Leaching characteristics of impurity ions with Ca2+ in calcium carbide slag during different acid leaching processes

    JIN Hening;ZHANG Pengyun;ZHANG Yabin;GUO Yanxia;School of Environment and Resources,Engineering Research Center of Ministry of Education for CO_2 Emission Reduction and Resource Utilization,Shanxi University;Shanxi Stone Age New Materials Technology Co.,Ltd.;

    The industrial processes of PVC,ethylene,and so on produced a significant amount of calcium carbide slag,leading to severe environmental issues and resource wastage.Acid leaching is a pre-treatment technique employed for extracting calcium from calcium carbide slag to produce high-value calcium-based chemicals like nano-calcium carbonate.However,impurity ions present in the slag are inevitably leached during this process,adversely affecting the purity of Ca~(2+).In the present study,HCl and NH_4Cl leaching systems were compared and the effect of various leaching conditions(molar ratio,temperature,agitation rate and time) on the leaching efficiencies of calcium and impurity ions(Al~(3+),Mg~(2+) and Fe~(3+)) was investigated.One-way experiments,orthogonal experiments,and analysis using different characteristics were conducted.The findings revealed that the conversion rate of Ca~(2+) was higher in the HCl system compared to the NH_4Cl system.Amongst different leaching conditions studied here,molar ratio had the most significant influence on Ca~(2+) conversion rate followed by time> temperature> stirring rate.Leaching agent dosage emerged as the most influential factor affecting ion leaching in both systems while other factors exhibited small or even negligible effects.The HCl leaching system can leach Al~(3+),Mg~(2+) and Fe~(3+),while the NH_4Cl system can only leach Al~(3+) and Mg~(2+),and its concentration is much lower than the HCl system.

    2024 11 v.30;No.171 [Abstract][OnlineView][Download 1207K]
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