Abstract:To address the issues of low operating current and operating efficiency long term less than 55%of the rated power in the roller press pre-grinding system,systematic optimization and transformation were implemented.The structure of the feeding device above the weighing bin was modified by adjusting the feeding point and adding bidirectional regulating valves,which solved the problems of uneven longitudinal distribution and horizontal segregation of materials from different sources in the bin,stabilized the feeding pressure of the roller press and effectively corrected deviation.Meanwhile,a multi-channel distributing device based on the principle of"reservoir spillway"was innovatively designed and installed at the inlet of the V-type separator,significantly improving the dispersion uniformity of materials,forming a stable and continuous material curtain,enhancing the separation efficiency and reducing the circulation of fine powder.After the transformation,the operating current of the roller press increased stably from 35A to 45A,the roller gap deviation decreased from 16mm to within 3mm,and the system operating pressure reached the set value.The system output increased by 10t/h,the power consumption per ton of cement grinding decreased by 2kW·h/t,and the specific surface area and early strength of the cement product were improved.Calculated based on annual operating time,the annual electricity cost saving is about 740000 CNY,showing significant economic benefits.This practice indicates that optimizing feeding uniformity and improving separation efficiency are key to fully utilizing the efficiency of the roller press pre-grinding system and achieving energy saving and conservation in the grinding system.

Abstract:A company's 5 000t/d cement production line employed traditional asbestos board seals at the shaft end of its kiln ID fan.This configuration presented issues such as high material brittleness,susceptibility to wear,and severe air leakage at the shaft end.Analysis indicated a large gap(2mm)between the asbestos plate and the fan shaft in this sealing structure.Furthermore,the bypass damper of the SP waste heat boiler was maintained at 8%opening,leading to cold air infiltration,reduced thermal efficiency,limited waste heat power generation load,and frequent maintenance.A modification scheme was proposed,implementing a dual sealing structure combining reinforced graphite blocks and silicone plates.This design controls the gap between the fan shaft and the silicone plate to 3mm,while achieving zero clearance between the graphite block and the fan shaft.The structure features self-compensation and self-lubrication properties,making it suitable for high-temperature and high-negative-pressure conditions.After the modification,shaft end air leakage was completely eliminated,allowing the SP boiler bypass damper to be fully closed.The inlet air temperature of the vertical mill increased stably by 10℃.The waste heat power generation load increased by approximately 10kW·h/h,resulting in an annual electricity saving of about 45 000kW·h.The comprehensive economic benefit amounts to approximately 26 200 CNY per year.The maintenance cycle for the sealing structure has been extended from about 2 months to over 10 years.This modification significantly improves system thermal efficiency and economic performance,demonstrating considerable potential for broader application.

Abstract:Aiming at the problems of unsatisfactory cement particle size distribution,high water demand,and poor fluidity in the cement roller press finish grinding system caused by insufficient classification accuracy,a special multi-rotor high-efficiency classifier adapted to the system has been developed.This equipment adopts three or more independently adjustable rotors,enabling precise control and optimization of the particle size distribution of finished cement through flexible adjustment of rotational speed,rotation direction,and structural parameters.Multiple engineering application cases show that this classifier,can optimize the particle size of cement produced by the roller press final grinding system to an ideal state,achieving a significant reduction in system power consumption while maintaining key performance indicators comparable to those of the combined grinding system.Furthermore,the roller press final grinding system equipped with this classifier supports flexible switching among finish grinding,semi-finish grinding,and combined grinding production modes.It achieves the dual goals of energy saving,consumption reduction,and flexible production.

Abstract:In the context of the intensifying overcapacity contradiction and increasingly stringent environmental protection policies in the sand and gravel industry,the design of sand and gravel aggregate production lines is confronted with the dual challenges of efficiency improvement and refined management.Traditional design methods for aggregate production lines rely on manual experience,which rely on manual experience,are associated with problems such as large deviations in product proportion calculations,unreasonable equipment selection,and lengthy design cycles.Based on a comprehensive database of process equipment,this study developed a set of process design and simulation system software for sand and gravel aggregate production lines,which integrates functions including intelligent drawing of process design flowcharts,dynamic calculation of product proportions,automatic analysis of product particle size distribution curves,and optimization of main equipment selection.The software is capable of supporting flexible switching between multiple modes of product schemes.Verification by a limestone aggregate production line project with an annual output of 3 million tons in East China shows that after the application of this software,the design efficiency is improved by approximately 100%,and the accuracy rate of equipment selection reaches 92%.This significantly enhances the market adaptability of the production line,providing reliable technical support for the digital and intelligent design of sand and gravel aggregate production line projects.

Abstract:In view of the characteristics of dispersed site layout and complex risk points in aggregate production line,combined with a granite aggregate production line with an annual output of 3.70×106m3,the design method and implementation process of the automatic fire alarm system are systematically elaborated.The production line covers the mining area and processing area,equipped with 7 electrical rooms and two fire pump rooms.A control center alarm system is adopted,with the main and subfire control rooms linked via optical fiber.The design follows eight current codes,with focus on selecting pointtype smoke fire detectors in electrical rooms and other key areas.The layout density is determined based on architectural parameters while considering the influence of structural beams.Cable-type linear heat detectors are employed in cable trenches,laid in a sinusoidal waveform to achieve continuous monitoring.Taking the E11A electrical room as an example,the planar arrangement of detectors,installation of heat-sensitive cables,and key points of module installation are described in detail.The system is also integrated with the emergency lighting system.The design has passed the fire protection review and provides a feasible technical reference for similar production line.

Abstract:To address the challenges posed by stringent environmental regulations,scarcity of coal resources,and carbon emission trading mechanisms,this study explores the potential of utilizing coal slag as a substitute for fly ash—an aluminous corrective material—in cement clinker production.The objective is to enhance resource efficiency and achieve cost-effective,low-carbon manufacturing.Comparative analysis of the chemical and mineralogical characteristics revealed that while both are aluminosilicate materials,coal slag possesses distinct advantages:lower loss on ignition,higher alumina content,lower magnesia content,and significant pozzolanic activity due to its abundance of reactive silica and alumina.Burnability tests conducted at 1 400℃demonstrated that raw meal mixtures incorporating coal slag exhibited superior performance compared to those with fly ash,with the improvement being more pronounced at higher substitution rates.Industrial application verification confirmed these findings,showing a 22℃reduction in the outlet gas temperature of the preheater's first-stage cyclone,a decrease of 2.5t/h in calciner coal consumption,and an overall reduction in the standard coal consumption per ton of clinker produced.The enhancement mechanism is attributed to the combined effects of lowered partial pressure of CO2 during calcination(which reduces the decomposition temperature of calcium carbonate),controlled magnesia content,and the pozzolanic reactivity of coal slag,which facilitates liquid phase formation.This research concludes that the use of coal slag offers a technically viable and economically beneficial pathway to improve clinker burnability and reduce energy consumption in cement plants.

Abstract:To address the development demands for carbon emission reduction technologies in the cement industry and the design of oxy-fuel combustion calciners,this study investigated the effect of high-concentration CO2 on cement raw meal decomposition under oxy-fuel combustion conditions by using thermogravimetric analysis(TGA).Two raw meal samples from an existing production line of a domestic cement plant were investigated,the key parameters including weight loss curve,weight loss rate,decomposition temperature and decomposition time of the raw meal were measured at a heating rate of 10℃/min.In addition,the decomposition characteristics of the above-mentioned raw meal under oxy-fuel combustion conditions were compared with the experimental results of the raw meal samples from another cement plant.The results show that with the CO2 concentration increasing from 30％to 90％,the initial decomposition temperature and complete decomposition temperature of the raw meal increase continuously.This is mainly due to the thermodynamic inhibition effect of high CO2 partial pressure on CaCO3 decomposition,which requires increasing the temperature to offset this effect.After replacing air with O2-CO2 mixed gas,the complete decomposition temperature of the raw meal increases by about 60℃～100℃.Meanwhile,the complete decomposition time of the raw meal is shortened to 4～6min under the high-concentration CO2 atmosphere,because the elevated temperature improves the reaction kinetic rate,which partially offsets the thermodynamic inhibition effect of CO2.Moreover,the decomposition temperature of raw meal samples from the two plants is about 940℃under the CO2 concentration of 80％.

Abstract:Siliceous residue is a solid waste generated during the production processes of metallurgical or chemical enterprises,whose main chemical components are SiO2 and Al2O3.To achieve its resource utilization,this study,in accordance with relevant national standards,conducted a comprehensive detection of the chemical composition,pozzolanic activity,potential hydraulic properties,radioactivity,and leachable heavy metal content of metallurgical siliceous residue around Tongling City.The results indicate that all indicators of this siliceous residue meet the technical requirements for cement admixtures,and it has the basic application conditions as an admixture for P·O42.5 cement.Further small mill tests and large mill tests revealed that when 3.0%siliceous residue was used to replace fly ash in cement production,the cement setting time was shortened by approximately 20 minutes,the water demand for standard consistency decreased by 0.4%,the fluidity of the standard consistency paste increased by 44mm,and the 3d and 28d compressive strengths showed slight improvements.The annual comprehensive economic benefit is estimated to be approximately 2 million CNY.This study has provided a scientific theoretical basis and a feasible technical solution for the resource utilization of siliceous residue.

Abstract:In response to the national"energy saving and carbon reduction"strategy and the requirement to reduce the production cost of cement clinker,experimental research and practical application optimization were conducted on two 2500t/d cement clinker production lines for partially substituting limestone with magnesium slag in raw meal proportioning and clinker burning.By analyzing the basic characteristics of magnesium slag and the changes in the quality of raw materials,fuels,raw meal,and clinker before and after using magnesium slag,targeted measures such as equipment modifications and process parameter optimization were proposed.These measures effectively resolved production issues arising during the magnesium slag burning process,including scaling in the precalciner cone,formation of long and thick coating in the rotary kiln,and instability in clinker quality.Practice shows that after partially substituting limestone with magnesium slag,the precalciner kiln system achieved stable operation.The actual coal consumption decreased by 8.1kg/t.cl,the standard coal consumption decreased by 6.21kg/t.cl,and the carbon emission reduction in clinker reached 0.066 7t/t.cl.Meanwhile,the 3d and 28d compressive strengths of clinker increased by 5.2MPa and 2.2MPa,respectively,achieving multiple goals of saving coal,reducing carbon emissions,lowering costs,and improving quality,has provided a practical reference for the resource utilization of industrial waste residues and the green,low-carbon development of the cement industry.

Abstract:The lubrication system of a gyratory crusher is required to supply oil to two oil circuits,namely the MPS oil cylinder and the lower frame bushing.However,these two circuits face working conditions such as a large difference in pressure loss,pressure loss varying with temperature and oil viscosity,different flow requirements,and a higher lubrication priority for the MPS oil cylinder circuit.Traditional throttle valves cannot meet the requirements due to inadequate flow stability.This paper introduces the composition and working principle of the lubrication system of gyratory crushers,analyzes the flow requirements of the two oil circuits,and designs a novel manifold valve block:Circuit A(MPS oil cylinder circuit)adopts a speed control valve composed of a differential pressure reducing valve and a fixed throttle plug connected in series,and an overflow valve is installed in Circuit B(lower frame bushing circuit)to ensure the working pressure of the differential pressure reducing valve.This design achieves priority lubrication of the MPS oil cylinder circuit,and the flow rates of the two oil circuits have high stability independent of external loads and oil temperature fluctuations.Taking a certain specification of gyratory crusher of an enterprise as an example,when the total lubricating oil flow rate is 300L/min,the flow rates of Circuit A and Circuit B stably reach 170L/min and 130L/min respectively.This guarantees prioritized lubrication of Circuit A and sufficient lubrication for both target points,which significantly improves the operation stability,reliability and economy of the gyratory crusher.

Abstract:With the advancement of the"Made in China 2025"strategy,the digital transformation of traditional manufacturing has become a key factor in enhancing the core competitiveness of enterprises.As a typical traditional manufacturing sector,the cement industry has long faced challenges such as outdated equipment management methods,frequent unplanned downtime,insufficient data value mining,high operation and maintenance costs,and significant pressure on safety production.This paper takes the intelligent equipment management system construction project in a cement plant as the research subject.It elaborates on the system's overall"acquisition layer,data layer,and application layer"and details the practical application of core modules such as online monitoring,intelligent video analysis,intelligent diagnostics,and operation and maintenance management platforms.The effectiveness of the system is also analyzed.The results indicate that the system can improve inspection efficiency by more than 50%,reduce unplanned downtime by 70%,lower annual operation and maintenance costs by 25%～35%,and significantly enhance safety production assurance capabilities.This provides a feasible technical solution and implementation path for the digital transformation of equipment management in the cement industry.

Abstract:With the deepening advancement of the"dual carbon"strategy,carbon emission reduction in the cement industry has become a core task for its sustainable development.As hazardous waste generated by the petroleum industry,the harmless and resource-efficient disposal of oil sludge represents a significant challenge in environmental protection.Cement kilns,leveraging their unique advantages of high temperature,large capacity,and alkaline environment,achieve dual benefits of environmental and economic gains in the co-disposal of oil sludge.This paper systematically analyzes the physicochemical properties of oil sludge and details the process flows and emission reduction effects of three mainstream technical pathways:direct pumping disposal,mixed pumping disposal,and disposal after pretreatment and dewatering.It further explores two cutting-edge technological trends—pre-combustion and pyrolysis—and proposes optimization directions to address current challenges such as increased energy consumption and kiln condition fluctuations during disposal.This research provides theoretical support for establishing a clean,low-carbon energy utilization system within the cement industry.

Abstract:Against the backdrop of the green and low-carbon transformation and capacity upgrading of the cement industry,the retrofit of the kiln tail preheater is a key measure to improve energy efficiency and realize energy conservation and emission reduction,issues such as structural compatibility,load transmission and construction safety are of crucial importance.Based on engineering practice,aiming at the structural problems in the internal retrofit of the 5-stage preheater,this paper systematically sorts out typical renovation types including the heightening renovation of the precalciner inside the preheater tower,the addition of a new precalciner outside the tower(supported column scheme),and the transformation of the 5-stage preheater into a 6-stage one,and deeply analyzes the structural characteristics,mechanical behavior and technical difficulties of various schemes.It summarizes the reinforcement technologies for key parts such as steel beams,steel columns,foundation,column base joints and the void defects of concrete-filled steel tube columns,and proposes a structural inspection and appraisal process with"investigation-detection-calculation-evaluation"as the core.Finally,it is pointed out that the structural reinforcement for more difficult renovations such as the upgrading from 5-stage to 7-stage preheater needs continuous breakthroughs in three aspects:load optimization,innovation of analysis methods and application of new reinforcement technologies,so as to provide technical support for similar projects in the industry.

Abstract:The traditional roller arm sealing system and mill return material sealing system of HRM4800 raw meal vertical roller mill suffer from poor sealing and air leakage issues.These deficiencies lead to reduced internal mill air temperature,increased load on the circulation fan and kiln tail fan,higher specific power consumption for raw meal grinding,elevated oxygen content in kiln stack flue gas,and increased denitrification costs.To address these challenges,an optimized retrofit solution was implemented:the roller arm sealing system was upgraded to a new combined structure of"labyrinth seal+multi-bellows flexible connection",with the multi-bellows flexible connection fabricated from high-molecular wear-resistant polyurethane material to ensure sealing conformity and durability.Simultaneously,the gravity-weighted flap air lock valve at the mill return material inlet was retrofitted with a fully enclosed vibratory feeder,achieving complete airtightness throughout the material conveying process.After the retrofit,system air leakage was effectively controlled,and the on-site working environment was significantly improved.Operational data shows that the average oxygen content in kiln stack flue gas decreased by 0.57%,the specific power consumption for raw meal grinding dropped by 0.2kW·h/t,the average operating power of the kiln tail fan decreased by 95kW,annual carbon emissions were reduced by approximately 1 777t,and annual comprehensive economic benefits reached 2.533 2 million CNY,demonstrating outstanding energy-saving,consumption-reducing,and environmental protection performance.

Abstract:With the rapid advancement of industrial modernization and urbanization in China,the demand for efficient,safe,and environmentally friendly disposal of fluorine-containing sludge has become increasingly urgent.This study explores the feasibility and technical advantages of co-processing fluorine-containing sludge in cement kilns.Taking a 4 500t/d new dry-process cement kiln of a company as an example,a technical analysis was conducted,and a co-disposal process scheme of"pretreatment-metering-blending-kiln incineration"was designed.Research indicates that this process achieves reduction and harmless disposal of fluorine-containing sludge while simultaneously solidifying heavy metals,suppressing acidic substance emissions,and avoiding secondary pollution.In practical operation,when fluoride-containing sludge is added at a ratio of 0.5%～1.5%of raw materials,the coal consumption can be reduced by 1.0～2.0kg per ton of clinker.The 3d and 28d compressive strengths of clinker are increased by approximately 2.61%and 1.38%,respectively,with a slight increase in output.The emissions of fluorine and chlorine meet the requirements of national standards,achieving both environmental and economic benefits.

Abstract:To advance energy conservation and carbon reduction in the cement industry,aerogel composite thermal insulation materials were first applied on a large scale in the renovation of the kiln system of this production line,adopting a composite configuration of"aerogel+calcium silicate board".By measuring the external surface temperature of the equipment after the transformation and comparing it with domestic plants A and B of the same specification,the results show that the aerogel composite thermal insulation material can significantly reduce the equipment surface temperature and the heat consumption of the production line.Meanwhile,the project's intelligent remote temperature monitoring system has improved the intelligence of temperature measurement and data accuracy.The study also identified thermal bridge effect at the brick support plates and anchors,indicating a need for targeted manner in the later stage.This research confirms that aerogel composite thermal insulation materials have both excellent thermal insulation effect and significant economic benefits in the cement industry,and have good promotion value.

Abstract:Full-scale numerical investigation was conducted to characterize NOX emission behavior in an industrial cement precalciner under staged combustion and biomass co-firing conditions.An Euler-Lagrange framework was employed to develop a three-dimensional model that resolves gas-phase combustion,pyrolysis of pulverized coal and biomass,as well as the formation and reduction pathways of NO.The model was validated through grid-independence analysis and comparison with on-site industrial measurements,with prediction deviations of temperature and NO concentration within 10%,demonstrating satisfac tory accuracy for industrial-scale simulation.The simulation results reveal that NO formation and reduction along the precalciner height exhibit a distinct evolution pattern,characterized by an initial low-rate conversion region,an intermediate strong reduction zone,and a downstream region dominated by NO formation.Based on this understanding,the effects of staged combustion optimization,including extension of the reduction zone and redistribution of fuel injection and oxygen concentration,were systematically evaluated.In addition,the NOX mitigation performance of biomass co-firing with pulverized coal(corn straw)was investigated.The results indicate that staged combustion effectively suppresses NO formation by enhancing the reducing atmosphere within the precalciner.Moreover,biomass co-firing provides an efficient alternative for NOX reduction without additional structural modification:when the biomass co-firing ratio is increased to 30%,the NO concentration at the precalciner outlet can be maintained at approximately 300ppm,while the raw meal decomposition rate remains above 92%.The present study provides quantitative insights into NOX emission characteristics and offers practical guidance for low-NOX operation of industrial cement precalciners.

Abstract:Taking the 6000t/d cement clinker production line of DCCP in Iraq as the research object,in view of the problems that the project's iron ore relies on imports from Turkey and Iran,with long transportation distances(about 323km and 281km respectively),high costs(average 75 US dollars/t),and unstable supply affected by seasons,the practice of reducing costs and increasing efficiency in the proportioning design of iron ore raw materials is carried out.By changing the traditional approach of solely relying on iron ore to meet the aluminum ratio in cement production,a proportioning scheme of"high-alumina clay+low-alumina clay"(in a ratio of 5:1)was adopted,with a reduction in iron ore usage.Combined with the physical properties and chemical composition analysis of raw materials,a series of tests such as grindability and flammability were carried out to optimize the proportioning parameters.The results show that after the commissioning,the average daily consumption of iron ore decreased by 0.11%,and the net savings in the annual comprehensive cost were 151 600 US dollars.The content of C4AF in clinker increased from 10.46%to 12.56%,effectively reducing the generation of fly sand during clinker calcination.Moreover,the compressive strengths of clinker at 2d and 28d increased by 3MPa and 2.5MPa respectively,and the quality met the EU cement standard(BS EN197-1:2011).This project is constructed overseas using Chinese technology,standards and equipment,providing a feasible technical reference solution for reducing raw material costs and improving efficiency for similar cement projects along the Belt and Road.

Abstract:In order to solve the problems of labor intensiveness,high cost and low efficiency in traditional manual cable laying in the electromechanical installation of cement engineering projects,a solution of mechanized cable laying is proposed.The cable conveyor and the engine power winch are the key equipment in this solution.The solution takes cable conveyors and electric winches as the core equipment which has the technical characteristics of portable equipment,flexible operation and less damage to the cable,and is suitable for complex construction conditions.Trials and comparisons conducted at three representative laying scenarios for a 5 000t/d cement clinker production line in Zhejiang Province demonstrated that the efficiency of mechanical cable laying for large cross-section cables can reach 76～102 meters per person per day,which is 6～8 times that of manual laying.For small cross-section cables,a combined human-machine approach improves efficiency by 21%compared to manual methods,while mechanized installation reduces costs by 81%～86%and effectively lowers both physical strain and safety risks.The mechanical cable laying can further guarantee the cable laying quality and efficiency by optimizing the preparatory work,arranging the equipment reasonably and strengthening the inspection after laying.It is a better construction solution for the electromechanical installation of cement engineering projects.

Abstract:To address the issues of idle equipment,high energy consumption,and elevated costs in traditional slag powder production at a 4 500t/d cement clinker production line,this study implemented technical upgrades to the idle coal vertical mill,pneumatic conveying system,fly ash storage,and dispersion system,establishing an integrated"production-conveyance-self-use-outbound"process for S95-grade slag.The project utilized waste heat from clinker grate coolers to replace hot blast stove energy,optimized grinding pressure and baffle ring height parameters of the coal vertical mill to improve slag grindability,and improved the slag conveying and metering systems to resolve issues of excessive grinding and storage collapse causing cement mill blockages.Post-upgrade,the slag's technical specifications met S95-grade slag quality standards,achieving a 28d activity index of 102.2%.When replacing 7%of clinker with slag in cement production,the system increased hourly mill output by 18t/h,reduced power consumption by 1.4kW·h/t,and generated annual economic benefits of 5.771 5 million RMB through self-use and outbound sales,successfully realizing efficient utilization of idle resources and achieving energy-saving transformation goals.