The purpose aims to improve the plate shearing section quality and metal yield by means of optimal blade clearance adjustment model of rolling-cut shear and accurate calculation of the maximum shearing force,as well a...The purpose aims to improve the plate shearing section quality and metal yield by means of optimal blade clearance adjustment model of rolling-cut shear and accurate calculation of the maximum shearing force,as well as for the system optimization design,structure optimization design to provide important basis.A 3500mm rolling shear of a large stainless steel factory was taken as the test object,and the blade clearance under different influence factors of the clearance value and the shearing section were tested.The optimized production accumulated data regression analysis and the rolling shear process of stainless steel shear test.The test results show that the optimal blade clearance adjustment module is a comprehensive function,which include steel plate thickness,material,temperature and shear plate volume.The shear stress at starting stage with the relative penetration depth increases affected by the above factors,and the fracture peak decreases rapidly after being cut into the roll phase constant.展开更多
Waste heat recovery from hot steel slag was determined in a granular bed through the combination of numerical simulation and an industrial test method.First,the effective thermal conductivity of the granular bed was c...Waste heat recovery from hot steel slag was determined in a granular bed through the combination of numerical simulation and an industrial test method.First,the effective thermal conductivity of the granular bed was calculated.Then,the unsteady-state model was used to simulate the heat recovery under three different flow fields(O-type,S-type,and nonshielding type(Nontype)).Second,the simulation results were validated by in-situ industrial experiments.The two methods confirmed that the heat recovery efficiencies of the flow fields from high to low followed the order of Nontype,S-type,and O-type.Finally,heat recovery was carried out under the Nontype flow field in an industrial test.The heat recovery efficiency increased from~76%and~78%to~81%when the steel slag thickness decreased from 400 and 300 to 200 mm,corresponding to reductions in the steel slag mass from 3.96 and 2.97 to 1.98 t with a blower air volume of 14687 m^(3)/h.Therefore,the research results showed that numerical simulation can not only guide experiments on waste heat recovery but also optimize the flow field.Most importantly,the method proposed in this paper has achieved higher waste heat recovery from hot steel slag in industrial scale.展开更多
A process of ＂Methanol or Dimethylether to Olefins＂ developed by Dalian Institute of Chemical Physics （DICP）, designated as the DMTO process, has attained great success in industrial scaling up testing. DICP, by c...A process of ＂Methanol or Dimethylether to Olefins＂ developed by Dalian Institute of Chemical Physics （DICP）, designated as the DMTO process, has attained great success in industrial scaling up testing. DICP, by collaborating with the Xinxing Coal Chemical Co., Ltd. of Shaanxi Province and the Luoyang Petrochemical Engineering Co. of the SINOPEC Group, operated successfully a 50t（methanol）/d unit for the conversion of methanol to lower olefins, with a methanol conversion of close to 100%, and a selectivity to lower olefins（ethylene, propylene and butylenes） of higher than 90%. On 23rd August, the industrial test project has passed a state appraisal. The experts of the Appraisal Group, headed by Prof. YUAN Qingtang, academician of Chinese Academy of Engineering, drew the conclusions that the DMTO process, by utilizing a proprietary SAPO-34 catalyst system and a recycling fluidized bed reaction system for the production of lower olefins from methanol, is the first unit in the world having a capacity of producing nearly ten thousand tons lower olefins per year. The technological level of the industrial test is at a leading position internationally. This accomplishment will provide a sound base for the subsequent commercialization of the DMTO process.展开更多
The cryogenic hydraulic turbine can be used to replace the conventional JeT valve for LNG or mixed refrigerant throttling and depressurization in a natural gas liquefaction plant.This advanced technology is not only t...The cryogenic hydraulic turbine can be used to replace the conventional JeT valve for LNG or mixed refrigerant throttling and depressurization in a natural gas liquefaction plant.This advanced technology is not only to enhance the efficiency of the liquefaction plant,but to usher a new trend in the development of global liquefaction technologies.China has over 136 liquefaction plants,but the cryogenic hydraulic turbines have not been deployed in industrial utilization.In addition,these turbines cannot be manufactured domestically.In this circumstance,through working on the key technologies for LNG hydraulic turbine process&control system development,hydraulic model optimization design,structure design and manufacturing,the first domestic cryogenic hydraulic turbine with a flow rate of 40 m^(3)/h was developed to recover the pressure energy from the LNG of cold box.The turbine was installed in the CNOOC Zhuhai Natural Gas Liquefaction Plant for industrial tests under multiple working conditions,including start-stop,variable flow rates and variable rotation speeds.Test results show that the domestic LNG cryogenic hydraulic turbine has satisfactory mechanical and operational performances at low temperatures as specified in design.In addition,the process&control system and frequency-conversion power-generation system of the turbine system are designed properly to automatically and smoothly replace the existing LNG JeT valve.As a result,the domestic LNG cryogenic hydraulic turbine system can improve LNG production by an average of 2%and generate power of 8.3 kW.展开更多
China’s Ministry of Commerce(MOFCOM)and the Ministry of Industry and Information Technology(MIIT)have designed a stress-test for China’s labor-intensive industries,
The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as diff...The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent.In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed.First,the composite hard roof cutting short cantilever beam(SCB)model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently,the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue.The control technology was finally verified through onsite engineering experiments in terms of composite hard roof.The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway.The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6,respectively,and the maximum and average working resistances of the working face support decreased by 10.9%and 13.8%,respectively.Consequently,the deformations of reserved entry decreased,and entry steadiness was enhanced.The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.展开更多
The top-bottom combined blowing converter mainly adopts the blowing method of top-blowing oxygen and bottom-blowing nitrogen.In the production process,there are some disadvantages,such as a significant temperature dif...The top-bottom combined blowing converter mainly adopts the blowing method of top-blowing oxygen and bottom-blowing nitrogen.In the production process,there are some disadvantages,such as a significant temperature difference between the top and bottom of the molten pool,inadequate gas permeability of bottom blowing,and low decarburization efficiency.Therefore,we propose a novel bottom-blowing gas doped oxygen process to enhance the smelting conditions in the converter.The 500 kg medium frequency induction furnace with top and bottom-blowing function was used to explore the influence of the proportion of bottom-blowing gas doped oxygen on the smelting effect in different smelting cycles.Subsequently,industrial experimental verification was carried out on a 60 t converter.The results of intermediate frequency furnace experiments demonstrate that the bottom-blowing gas doped oxygen process exhibits a superior heating rate and decarburization efficiency during the initial and final stages of blowing compared to pure N2 used for bottom-blowing.Simultaneously,the dephosphorization efficiency exhibited an initial increase followed by a subsequent decrease as the bottom-blowing oxygen content increased.The industrial test of 60 t converter validates the findings above.Moreover,when the oxygen content in bottom-blowing gas is 5%,the average blowing time reduces by 54 s,and the minimum endpoint carbon-oxygen equilibrium reaches 0.00219 under this condition.The results demonstrate that the appropriate amount of oxygen doped in bottom-blowing gas can effectively enhance the metallurgical conditions of the converter and improve production efficiency.展开更多
The extent of inclusion modification achieved after adding various contents of rare earth elements to 304 stainless steel in practical applications was explored,additionally the pitting behavior of the inclusions in a...The extent of inclusion modification achieved after adding various contents of rare earth elements to 304 stainless steel in practical applications was explored,additionally the pitting behavior of the inclusions in a chloride environment before and after modification.The mechanisms by which the compositions of inclusions evolved throughout the production process in response to various rare earth element(REE)contents were investigated,and their consequential impact on the corrosion resistance of steel was evaluated.The results indicated that with increasing rare earth content from 0 to 50.37×10^(−6),REE inclusions were preferentially generated in the following order when they were modified:REAlO_(3)→RE_(2)O_(2)S→RE_(2)O_(3).The inclusion size and density were negatively correlated and positively correlated with the REE content in 304 stainless steel,respectively.The formation of Mg–Al spinel and MnS in the continuously cast billet was suppressed by the addition of rare earth elements.The voltage potential differences between the REE-modified inclusions and the steel substrate were obviously less than those between the unmodified inclusions and the steel substrate.The addition of rare earth elements contributed to the improvement in the corrosion resistance of 304 stainless steel.展开更多
A new technology characterized by rapidly non-mechanical settlement of unclassified tailings was developed based on a large number of tests, and dynamic settlement and continual slurry preparation without hardening in...A new technology characterized by rapidly non-mechanical settlement of unclassified tailings was developed based on a large number of tests, and dynamic settlement and continual slurry preparation without hardening in vertical sand silo were eventually realized by the addition of an effective flocculating agent (NPA). The results show that the sedimentation velocity of interface between unclassified tailings and water after the addition of NPA increases by 10-20 times, the sedimentation mass fraction of unclassified tailings at the bottom of vertical sand silo is up to 64%, the solid particle content of waste water meets the national standard, and the side influences of NPA can be removed by the addition of fly ash. The industrial test result shows that the system, the addition manner and the equipments are rational, and the vertical sand silo is used efficiently. This developed system is simple with large throughput, and the processing cost is 2.2 yuan(RMB)/m3, only 10%-20% of that by mechanical settlement.展开更多
A non-pillar coal-mining technology with an automatically formed entry is proposed,which reduces the waste of coal resources and the underground entry drivage workload.Three key techniques in this technology cooperate...A non-pillar coal-mining technology with an automatically formed entry is proposed,which reduces the waste of coal resources and the underground entry drivage workload.Three key techniques in this technology cooperate to achieve automatic formation and retaining of the gob-side entry,and to realize nonpillar mining.Constant-resistance large deformation(CRLD)support ensures the stability of the entry roof;directional presplitting blasting(DPB)separates the entry roof and the gob roof;and a blockinggangue support system(BGSS)integrates the caved rock material as an effective entry rib.An industrial test was conducted to verify the engineering effects of these key techniques.The field application results showed that the retained entry was under the pressure-relief zone due to the broken-expansion nature of the caved rock mass within the DPB height.After going through a provisional dynamic pressure-bearing zone,the retained entry entered the stability zone.The final stable entry meets the requirements of safety and production.The research results demonstrate the good engineering applicability of this technology.By taking the framework of the technology design principles into consideration and adjusting the measures according to different site conditions,it is expected that the proposed non-pillar coal-mining technology can be popularized on a large scale.展开更多
The iron element in electric arc furnace(EAF)slag is extremely difficult to recycle due to the low specific magnetic susceptibility of the RO phase(a solid solution of FeO,MgO,CaO,and MnO).Landfilling EAF slag is stri...The iron element in electric arc furnace(EAF)slag is extremely difficult to recycle due to the low specific magnetic susceptibility of the RO phase(a solid solution of FeO,MgO,CaO,and MnO).Landfilling EAF slag is strictly forbidden for environmental consideration because of poisonous Cr^(6+)leaching.The original RO phase could be transformed to a spinel structure,whose specific magnetic susceptibility is much higher than that of other minerals,through hot modification,resulting in significantly increased iron recovery by magnetic separation.Precipitation of spinel crystals encloses chromium,such that iron and chromium could be recovered simultaneously.The chromium in obtained iron concentrates is considerably useful for stainless steel making rather than polluting the environment.As a result,recovering iron and chromium is truly beneficial for cleaner production.Hot modification of EAF slag should be conducted at 1500-1600ºC for at least 60 min to guarantee homogeneous liquid slag.The liquid slag was poured onto an iron mold to obtain modified slag(MS)through air quenching.MS was characterized by thermodynamic analysis,X-ray diffraction,and scanning electron microscopy combined with energy-dispersive spectroscopy to correlate the relationship between mineral structures and iron recovery.The iron recovery rate of MS first increased and then decreased with increasing modifier.It was less than 10%when the modifier addition amount was below 12 wt.%,but it increased rapidly as the modifier addition amount increased from 16 to 24 wt.%,mainly due to spinel formation.The highest iron recovery rate was 81.9%when the modifier amount reached 20 wt.%.Meanwhile,Cr^(6+)was enriched in the spinel phase but was not observed in other minerals.Industrial tests were performed on-site with the modifier ranging from 12 to 18 wt.%because additional heat was not provided during the tests.Results showed that MS with 18 wt.%modifier addition exhibited an iron recovery rate of 61.0%,much higher than that(34.6%)of the original slag.展开更多
The temperature distribution of iron ore pellet bed in grate has a significant effect on pellet production and quality control, but the related work is scarce. A well-designed test was successfully carried out by mean...The temperature distribution of iron ore pellet bed in grate has a significant effect on pellet production and quality control, but the related work is scarce. A well-designed test was successfully carried out by means of tracking measurement and the temperature distribution and variation in pellet layers were obtained. The effects of blast tem- perature, blast velocity and oxidation reaction on the pellet layer temperature were studied. According to the analy- sis, the inlet air temperature in the up-draught drying zone （UDD） and blast temperature in the Preheating I （PH I） zone should be raised, and the length of the down-draught drying zone （DDD） should be properly increased.展开更多
A three-dimensional finite element model coupled with heat transfer,shrinkage accumulation and high temperature deformation was established forϕ690 mm round bloom in continuous casting,and it was verified by surface t...A three-dimensional finite element model coupled with heat transfer,shrinkage accumulation and high temperature deformation was established forϕ690 mm round bloom in continuous casting,and it was verified by surface temperature,shell thickness,contour shape and porosity size by measurement.The compensation area of the shrinkage zone increases as the reduction amount increases.The compensation effect by the reduction of the unit with liquid core is about two times higher than others with fully solid matrix at a given reduction amount.A mathematical method to determine the reduction parameters for large-sized round bloom during continuous casting was proposed by the multi-rollers strategy.For theϕ690 mm round bloom,the suitable reduction parameters for Nos.2–6 units are suggested as 15,15,10,10,10 mm with a casting speed of 0.26 m min^(-1)to close the shrinkage with a diameter of about 17.5 mm in average.The industrial test on the reduction of large-sized round bloom for LZ50 steel was carried out.A total amount of 65–70 mm reduction was realized in the bloom for different casting speeds.The maximum diameter of the central porosity is about 16.3 mm in the longitudinal section at the casting speed of 0.24 m min^(-1),and it decreases to 7.3 mm after 65 mm reduction.Meanwhile,the maximum diameter of the central porosity is about 18.7 mm at 0.26 m min^(-1),while it decreases to 4.1 mm by a reduction of 70 mm.Finally,the difference of the solidification end reduction on round bloom and rectangular or square bloom is theoretically compared.Low deformation resistance and high bulge effect were found in round bloom compared to rectangular bloom.According to the results about solidification contraction accumulation and reduction efficiency in round bloom,the suitable reduction zone to control the central porosity during continuous casting is suggested to be 0.5–1.0.展开更多
This paper presents the performance and characteristics of new-type sulfur tolerant shift catalyst QDB-04 and its industrial side-line test as well as the first-time industrial application in Lunan Chemical Fertilizer...This paper presents the performance and characteristics of new-type sulfur tolerant shift catalyst QDB-04 and its industrial side-line test as well as the first-time industrial application in Lunan Chemical Fertilizer Plant of Shandong in China. The results show that the catalyst has high strength and strength stability, good low temperature activity and stability as well as low potassium bleeding ratio which well meet for the requirements of the methanol plant on catalyst performance in Lunan Chemical Fertilizer Plant.展开更多
In the complete green synthesis technology chain,bio-syngas production remains the“first hurdle”.Especially,the“tar”problem in biomass gasification urgently needs to be solved.Recently,our team,in collaboration wi...In the complete green synthesis technology chain,bio-syngas production remains the“first hurdle”.Especially,the“tar”problem in biomass gasification urgently needs to be solved.Recently,our team,in collaboration with Jinan Huangtai Gas Stove Co.,Ltd.,completed a 10,000-ton industrial test and technical verification of fluidized bed two-stage O_(2)/steam gasification for production of syngas from biomass.The test results showed that the fluidized bed two-stage gasification was operated continuously and stably for over 110 h with various biomass feedstocks.Additionally,the lowest tar content in the produced gas reached 0.58 g/Nm^(3).The fly ash collected from the continuous test contained carbon of about 30 wt%.Thus,the technology was well proved for large-scale biomass gasification and production of syngas in terms of technical feasibility and operational stability.展开更多
Noise presents health and social problems in industrial operations and is mainly related to machinery use.Noise is an important factor that affects work environment,and consequently affects both workers'health and...Noise presents health and social problems in industrial operations and is mainly related to machinery use.Noise is an important factor that affects work environment,and consequently affects both workers'health and efficiency.The US OSHA(Occupational Safety and Health Administration)specify six on-the-j ob physical hazards to health,noise is one of those hazards.There is little or no information about occupational noise exposure of workers within industrial and manufacturing sectors in the Gaza Strip.This is due to the difficulty of conducting noise exposure surveillance in such occupations and the lack of awareness regarding this issue.The objective of the current study is to evaluate the exposure of workers in different industrial sectors to occupational noise using a combined measurement and questionnaire approach The present study was conducted in different utilities industries in the Gaza Strip,in order to evaluate the noise levels at those factories and to develop awareness campaign among those workers.From the obtained data,it can be seen that almost all workers are exposed to higher noise levels than the recommended one by OSHA.Therefore it is necessary to start awareness campaign which informs the workers about noise as an occupational hazard.展开更多
In response to the need in industry for a quick and reproducible method of measuring the flowability of powders in processes involving transport and storage, the apparently simple idea of measuring angle of repose has...In response to the need in industry for a quick and reproducible method of measuring the flowability of powders in processes involving transport and storage, the apparently simple idea of measuring angle of repose has been revived. The simple tester first used has evolved over a number of years into the present version which is shown to be capable of handling quite small samples of powders that are even slightly cohesive. Experimental data are presented and results shown to compare consistently with the better known Hausner ratio.展开更多
基金Item Sponsored by National Basic Research Program of China(2011CB612204)National Natural Science Foundation of China(51105264)
文摘The purpose aims to improve the plate shearing section quality and metal yield by means of optimal blade clearance adjustment model of rolling-cut shear and accurate calculation of the maximum shearing force,as well as for the system optimization design,structure optimization design to provide important basis.A 3500mm rolling shear of a large stainless steel factory was taken as the test object,and the blade clearance under different influence factors of the clearance value and the shearing section were tested.The optimized production accumulated data regression analysis and the rolling shear process of stainless steel shear test.The test results show that the optimal blade clearance adjustment module is a comprehensive function,which include steel plate thickness,material,temperature and shear plate volume.The shear stress at starting stage with the relative penetration depth increases affected by the above factors,and the fracture peak decreases rapidly after being cut into the roll phase constant.
基金financially supported by the National Natural Science Foundation of China(No.51972019)the National Key Research and Development Program of China(No.2019YFC1905702)。
文摘Waste heat recovery from hot steel slag was determined in a granular bed through the combination of numerical simulation and an industrial test method.First,the effective thermal conductivity of the granular bed was calculated.Then,the unsteady-state model was used to simulate the heat recovery under three different flow fields(O-type,S-type,and nonshielding type(Nontype)).Second,the simulation results were validated by in-situ industrial experiments.The two methods confirmed that the heat recovery efficiencies of the flow fields from high to low followed the order of Nontype,S-type,and O-type.Finally,heat recovery was carried out under the Nontype flow field in an industrial test.The heat recovery efficiency increased from~76%and~78%to~81%when the steel slag thickness decreased from 400 and 300 to 200 mm,corresponding to reductions in the steel slag mass from 3.96 and 2.97 to 1.98 t with a blower air volume of 14687 m^(3)/h.Therefore,the research results showed that numerical simulation can not only guide experiments on waste heat recovery but also optimize the flow field.Most importantly,the method proposed in this paper has achieved higher waste heat recovery from hot steel slag in industrial scale.
文摘A process of ＂Methanol or Dimethylether to Olefins＂ developed by Dalian Institute of Chemical Physics （DICP）, designated as the DMTO process, has attained great success in industrial scaling up testing. DICP, by collaborating with the Xinxing Coal Chemical Co., Ltd. of Shaanxi Province and the Luoyang Petrochemical Engineering Co. of the SINOPEC Group, operated successfully a 50t（methanol）/d unit for the conversion of methanol to lower olefins, with a methanol conversion of close to 100%, and a selectivity to lower olefins（ethylene, propylene and butylenes） of higher than 90%. On 23rd August, the industrial test project has passed a state appraisal. The experts of the Appraisal Group, headed by Prof. YUAN Qingtang, academician of Chinese Academy of Engineering, drew the conclusions that the DMTO process, by utilizing a proprietary SAPO-34 catalyst system and a recycling fluidized bed reaction system for the production of lower olefins from methanol, is the first unit in the world having a capacity of producing nearly ten thousand tons lower olefins per year. The technological level of the industrial test is at a leading position internationally. This accomplishment will provide a sound base for the subsequent commercialization of the DMTO process.
文摘The cryogenic hydraulic turbine can be used to replace the conventional JeT valve for LNG or mixed refrigerant throttling and depressurization in a natural gas liquefaction plant.This advanced technology is not only to enhance the efficiency of the liquefaction plant,but to usher a new trend in the development of global liquefaction technologies.China has over 136 liquefaction plants,but the cryogenic hydraulic turbines have not been deployed in industrial utilization.In addition,these turbines cannot be manufactured domestically.In this circumstance,through working on the key technologies for LNG hydraulic turbine process&control system development,hydraulic model optimization design,structure design and manufacturing,the first domestic cryogenic hydraulic turbine with a flow rate of 40 m^(3)/h was developed to recover the pressure energy from the LNG of cold box.The turbine was installed in the CNOOC Zhuhai Natural Gas Liquefaction Plant for industrial tests under multiple working conditions,including start-stop,variable flow rates and variable rotation speeds.Test results show that the domestic LNG cryogenic hydraulic turbine has satisfactory mechanical and operational performances at low temperatures as specified in design.In addition,the process&control system and frequency-conversion power-generation system of the turbine system are designed properly to automatically and smoothly replace the existing LNG JeT valve.As a result,the domestic LNG cryogenic hydraulic turbine system can improve LNG production by an average of 2%and generate power of 8.3 kW.
文摘China’s Ministry of Commerce(MOFCOM)and the Ministry of Industry and Information Technology(MIIT)have designed a stress-test for China’s labor-intensive industries,
基金This work described herein was supported by the Program of China Scholarship Council(202206430008)the National Natural Science Foundation of China(NSFC)(52074300 and 52304111)+1 种基金the Yueqi Young Scholars Project of China University of Mining and Technology Beijing(2602021RC84)the Guizhou province science and technology planning project([2020]3007 and[2020]2Y019).
文摘The 110-mining method,a rising and revolutionary non-pillar longwall mining method,can obviously expand coal extraction ratio and minimize roadway incidents.However,in case of composite hard roof,problems such as difficulty in commanding the entry steadiness and insufficient fragmentation and bulking of the goaf gangue are prevalent.In this study,a 110-mining method for roadway surrounding rock stability control technology based on a compensation mechanism was proposed.First,the composite hard roof cutting short cantilever beam(SCB)model was built and the compensation mechanism including stress and space dual compensation was studied.Subsequently,the controllable elements influencing the roadway steadiness were confirmed to consequently put forward a control technology based on stress compensation for entry support and space compensation for the fragmentation and bulking of goaf gangue.The control technology was finally verified through onsite engineering experiments in terms of composite hard roof.The adoption of the 110-mining method with compensation control technology indicated good support effect on the roadway.The initial and residual expansion coefficients of the goaf gangue increased by 0.6 and 0.6,respectively,and the maximum and average working resistances of the working face support decreased by 10.9%and 13.8%,respectively.Consequently,the deformations of reserved entry decreased,and entry steadiness was enhanced.The presented technique and effects got probably have practical values for non-pillar mining functions in comparable field.
基金supported by the National Natural Science Foundation of China(No.U21A20317)the National Key Research and Development Program of China(No.2017YFB0304201).
文摘The top-bottom combined blowing converter mainly adopts the blowing method of top-blowing oxygen and bottom-blowing nitrogen.In the production process,there are some disadvantages,such as a significant temperature difference between the top and bottom of the molten pool,inadequate gas permeability of bottom blowing,and low decarburization efficiency.Therefore,we propose a novel bottom-blowing gas doped oxygen process to enhance the smelting conditions in the converter.The 500 kg medium frequency induction furnace with top and bottom-blowing function was used to explore the influence of the proportion of bottom-blowing gas doped oxygen on the smelting effect in different smelting cycles.Subsequently,industrial experimental verification was carried out on a 60 t converter.The results of intermediate frequency furnace experiments demonstrate that the bottom-blowing gas doped oxygen process exhibits a superior heating rate and decarburization efficiency during the initial and final stages of blowing compared to pure N2 used for bottom-blowing.Simultaneously,the dephosphorization efficiency exhibited an initial increase followed by a subsequent decrease as the bottom-blowing oxygen content increased.The industrial test of 60 t converter validates the findings above.Moreover,when the oxygen content in bottom-blowing gas is 5%,the average blowing time reduces by 54 s,and the minimum endpoint carbon-oxygen equilibrium reaches 0.00219 under this condition.The results demonstrate that the appropriate amount of oxygen doped in bottom-blowing gas can effectively enhance the metallurgical conditions of the converter and improve production efficiency.
基金supported by the Guangxi Science and Technology Major Projects(Guike AA22068080 and ZY23055009)the National Natural Science Foundation of China(Grant Nos.52174322,52074198,and 52374342)supported by the Department of Science and Technology of Hubei Province(Grant Nos.2023AFB603 and 2023DJC140).
文摘The extent of inclusion modification achieved after adding various contents of rare earth elements to 304 stainless steel in practical applications was explored,additionally the pitting behavior of the inclusions in a chloride environment before and after modification.The mechanisms by which the compositions of inclusions evolved throughout the production process in response to various rare earth element(REE)contents were investigated,and their consequential impact on the corrosion resistance of steel was evaluated.The results indicated that with increasing rare earth content from 0 to 50.37×10^(−6),REE inclusions were preferentially generated in the following order when they were modified:REAlO_(3)→RE_(2)O_(2)S→RE_(2)O_(3).The inclusion size and density were negatively correlated and positively correlated with the REE content in 304 stainless steel,respectively.The formation of Mg–Al spinel and MnS in the continuously cast billet was suppressed by the addition of rare earth elements.The voltage potential differences between the REE-modified inclusions and the steel substrate were obviously less than those between the unmodified inclusions and the steel substrate.The addition of rare earth elements contributed to the improvement in the corrosion resistance of 304 stainless steel.
基金Project(2006BAB02A03) supported by National Key Technology Research and Development ProgramProject(2006BA02B05) supported by Key Programs for Science and Technology Development of China during the 11th Five Year
文摘A new technology characterized by rapidly non-mechanical settlement of unclassified tailings was developed based on a large number of tests, and dynamic settlement and continual slurry preparation without hardening in vertical sand silo were eventually realized by the addition of an effective flocculating agent (NPA). The results show that the sedimentation velocity of interface between unclassified tailings and water after the addition of NPA increases by 10-20 times, the sedimentation mass fraction of unclassified tailings at the bottom of vertical sand silo is up to 64%, the solid particle content of waste water meets the national standard, and the side influences of NPA can be removed by the addition of fly ash. The industrial test result shows that the system, the addition manner and the equipments are rational, and the vertical sand silo is used efficiently. This developed system is simple with large throughput, and the processing cost is 2.2 yuan(RMB)/m3, only 10%-20% of that by mechanical settlement.
基金This work was supported by the National Key Research and Development Program of China(2016YFC0600900)the Program of China Scholarship Council(201806430070).
文摘A non-pillar coal-mining technology with an automatically formed entry is proposed,which reduces the waste of coal resources and the underground entry drivage workload.Three key techniques in this technology cooperate to achieve automatic formation and retaining of the gob-side entry,and to realize nonpillar mining.Constant-resistance large deformation(CRLD)support ensures the stability of the entry roof;directional presplitting blasting(DPB)separates the entry roof and the gob roof;and a blockinggangue support system(BGSS)integrates the caved rock material as an effective entry rib.An industrial test was conducted to verify the engineering effects of these key techniques.The field application results showed that the retained entry was under the pressure-relief zone due to the broken-expansion nature of the caved rock mass within the DPB height.After going through a provisional dynamic pressure-bearing zone,the retained entry entered the stability zone.The final stable entry meets the requirements of safety and production.The research results demonstrate the good engineering applicability of this technology.By taking the framework of the technology design principles into consideration and adjusting the measures according to different site conditions,it is expected that the proposed non-pillar coal-mining technology can be popularized on a large scale.
基金supported by Sichuan Province Science_and Technology Program(201904a05020008)Anhui Province Science and Technology Program(2019YFSY0029)the Open Project Funding from State Key Laboratory of Solid Waste Reuse for Building Materials(No.SWR-2017-005).
文摘The iron element in electric arc furnace(EAF)slag is extremely difficult to recycle due to the low specific magnetic susceptibility of the RO phase(a solid solution of FeO,MgO,CaO,and MnO).Landfilling EAF slag is strictly forbidden for environmental consideration because of poisonous Cr^(6+)leaching.The original RO phase could be transformed to a spinel structure,whose specific magnetic susceptibility is much higher than that of other minerals,through hot modification,resulting in significantly increased iron recovery by magnetic separation.Precipitation of spinel crystals encloses chromium,such that iron and chromium could be recovered simultaneously.The chromium in obtained iron concentrates is considerably useful for stainless steel making rather than polluting the environment.As a result,recovering iron and chromium is truly beneficial for cleaner production.Hot modification of EAF slag should be conducted at 1500-1600ºC for at least 60 min to guarantee homogeneous liquid slag.The liquid slag was poured onto an iron mold to obtain modified slag(MS)through air quenching.MS was characterized by thermodynamic analysis,X-ray diffraction,and scanning electron microscopy combined with energy-dispersive spectroscopy to correlate the relationship between mineral structures and iron recovery.The iron recovery rate of MS first increased and then decreased with increasing modifier.It was less than 10%when the modifier addition amount was below 12 wt.%,but it increased rapidly as the modifier addition amount increased from 16 to 24 wt.%,mainly due to spinel formation.The highest iron recovery rate was 81.9%when the modifier amount reached 20 wt.%.Meanwhile,Cr^(6+)was enriched in the spinel phase but was not observed in other minerals.Industrial tests were performed on-site with the modifier ranging from 12 to 18 wt.%because additional heat was not provided during the tests.Results showed that MS with 18 wt.%modifier addition exhibited an iron recovery rate of 61.0%,much higher than that(34.6%)of the original slag.
基金Sponsored by National High Technology Research and Development Program of China (2007AA05Z215)
文摘The temperature distribution of iron ore pellet bed in grate has a significant effect on pellet production and quality control, but the related work is scarce. A well-designed test was successfully carried out by means of tracking measurement and the temperature distribution and variation in pellet layers were obtained. The effects of blast tem- perature, blast velocity and oxidation reaction on the pellet layer temperature were studied. According to the analy- sis, the inlet air temperature in the up-draught drying zone （UDD） and blast temperature in the Preheating I （PH I） zone should be raised, and the length of the down-draught drying zone （DDD） should be properly increased.
基金This work is financially supported by the Fundamental Research Funds for the Central Universities(No.FRF-TP-19-017A3)National Natural Science Foundation of China(No.51874026).
文摘A three-dimensional finite element model coupled with heat transfer,shrinkage accumulation and high temperature deformation was established forϕ690 mm round bloom in continuous casting,and it was verified by surface temperature,shell thickness,contour shape and porosity size by measurement.The compensation area of the shrinkage zone increases as the reduction amount increases.The compensation effect by the reduction of the unit with liquid core is about two times higher than others with fully solid matrix at a given reduction amount.A mathematical method to determine the reduction parameters for large-sized round bloom during continuous casting was proposed by the multi-rollers strategy.For theϕ690 mm round bloom,the suitable reduction parameters for Nos.2–6 units are suggested as 15,15,10,10,10 mm with a casting speed of 0.26 m min^(-1)to close the shrinkage with a diameter of about 17.5 mm in average.The industrial test on the reduction of large-sized round bloom for LZ50 steel was carried out.A total amount of 65–70 mm reduction was realized in the bloom for different casting speeds.The maximum diameter of the central porosity is about 16.3 mm in the longitudinal section at the casting speed of 0.24 m min^(-1),and it decreases to 7.3 mm after 65 mm reduction.Meanwhile,the maximum diameter of the central porosity is about 18.7 mm at 0.26 m min^(-1),while it decreases to 4.1 mm by a reduction of 70 mm.Finally,the difference of the solidification end reduction on round bloom and rectangular or square bloom is theoretically compared.Low deformation resistance and high bulge effect were found in round bloom compared to rectangular bloom.According to the results about solidification contraction accumulation and reduction efficiency in round bloom,the suitable reduction zone to control the central porosity during continuous casting is suggested to be 0.5–1.0.
文摘This paper presents the performance and characteristics of new-type sulfur tolerant shift catalyst QDB-04 and its industrial side-line test as well as the first-time industrial application in Lunan Chemical Fertilizer Plant of Shandong in China. The results show that the catalyst has high strength and strength stability, good low temperature activity and stability as well as low potassium bleeding ratio which well meet for the requirements of the methanol plant on catalyst performance in Lunan Chemical Fertilizer Plant.
基金supported by Liaoning Province Science and Technology Plan Joint Fund Doctoral Project(No.2023-BSBA-266)Youth Fund of National Natural Science Foundation of China(No.22208225)National Key Research and Development Program Project(No.2024YFB3411600).
文摘In the complete green synthesis technology chain,bio-syngas production remains the“first hurdle”.Especially,the“tar”problem in biomass gasification urgently needs to be solved.Recently,our team,in collaboration with Jinan Huangtai Gas Stove Co.,Ltd.,completed a 10,000-ton industrial test and technical verification of fluidized bed two-stage O_(2)/steam gasification for production of syngas from biomass.The test results showed that the fluidized bed two-stage gasification was operated continuously and stably for over 110 h with various biomass feedstocks.Additionally,the lowest tar content in the produced gas reached 0.58 g/Nm^(3).The fly ash collected from the continuous test contained carbon of about 30 wt%.Thus,the technology was well proved for large-scale biomass gasification and production of syngas in terms of technical feasibility and operational stability.
文摘Noise presents health and social problems in industrial operations and is mainly related to machinery use.Noise is an important factor that affects work environment,and consequently affects both workers'health and efficiency.The US OSHA(Occupational Safety and Health Administration)specify six on-the-j ob physical hazards to health,noise is one of those hazards.There is little or no information about occupational noise exposure of workers within industrial and manufacturing sectors in the Gaza Strip.This is due to the difficulty of conducting noise exposure surveillance in such occupations and the lack of awareness regarding this issue.The objective of the current study is to evaluate the exposure of workers in different industrial sectors to occupational noise using a combined measurement and questionnaire approach The present study was conducted in different utilities industries in the Gaza Strip,in order to evaluate the noise levels at those factories and to develop awareness campaign among those workers.From the obtained data,it can be seen that almost all workers are exposed to higher noise levels than the recommended one by OSHA.Therefore it is necessary to start awareness campaign which informs the workers about noise as an occupational hazard.
文摘In response to the need in industry for a quick and reproducible method of measuring the flowability of powders in processes involving transport and storage, the apparently simple idea of measuring angle of repose has been revived. The simple tester first used has evolved over a number of years into the present version which is shown to be capable of handling quite small samples of powders that are even slightly cohesive. Experimental data are presented and results shown to compare consistently with the better known Hausner ratio.
