The medium and low-temperature NH₃-SCR technology has been maturely applied in the range of 180℃ to 420℃, and is currently expanding from the cement industry into the steel industry. To meet the demands for energy conservation and reduced consumption, there is an urgent need for in-depth research into the actual operational behaviour of low-temperature SCR catalysts (<180℃). This paper takes SCR catalysts from a lime kiln at a certain steelworks which had been in operation for half a year as the subject of study. Catalysts characterization analysis and activity tests were conducted using techniques such as XRF, XRD, SEM-EDS, BET, TG and TPSR to investigate the deactivation mechanisms and the feasibility of regeneration. The results indicate that catalyst deactivation is primarily attributable to the coupled effects of carbon deposition and the accumulation of ammonium bisulfate and ammonium nitrate; the carbon deposits exist in the form of graphitic carbon. These deposits block the pore channels, leading to a significant reduction in the specific surface area and pore volume of the catalysts. Combined TG-DSC and TPSR analysis revealed that the deactivated catalyst exhibited significant weight loss between 350℃ and 500℃, with the maximum decomposition rate occurring near 440℃. This process comprised three stages: low-temperature dehydration, medium-temperature CO desorption, and high-temperature oxidation of carbon deposits and decomposition of ammonium salts. The decomposition of ammonium salts was the dominant process, and the overall reaction exhibited endothermic characteristics. Activity test results show that the deactivated catalyst must operate at temperatures above 250℃ to meet the emission limit of NOX, while effective oxidation of carbon deposits and decomposition of ammonium salts requires temperatures above 400℃. Consequently, on-site thermal regeneration is energy-intensive and not feasible. This study provides a reference for the prevention and control of deactivation, as well as the engineering application of low-temperature SCR catalysts in complex operating conditions within industries such as the cement industry.

 The current standard GB 31893-2015 "Limit and determination of the water-soluble chromium ( Ⅵ) content for cement" stipulates that the limit of water-soluble chromium ( Ⅵ) in cement is 10.0mg/kg. The determination method specified in the standard has problems such as cumbersome operation, timeconsuming procedures, high cost and large solid waste generation. In this paper, water dispersion - flame atomic absorption spectrophotometry was introduced for the rapid determination of water-soluble chromium ( Ⅵ) content in cement, and the effects of water-cement ratio (10∶1, 10∶2, 10∶4) and dispersion methods (glass rod stirring, ultrasonic dispersion) on the determination results were investigated respectively. The results showed that the optimal conditions were a water-cement ratio of 10∶1 combined with ultrasonic dispersion; the relative standard deviations of seven parallel tests were 0.42% and 0.56% respectively, and the deviations between the measured values and the standard values met the requirements of the repeatability limit and reproducibility limits of GB 31893-2015. The pretreatment time of this method is no more than 10 min, and it produces virtually no solid waste. It is suggested to adopt this method as the primary screening method and establish a determination system of "primary screening - reference method verification" (with a screening limit of 8mg/kg; samples exceeding the limit shall be retested by the diphenylcarbazide method), so as to provide a technical reference for the revision of GB 31893-2015.

As one of the major industrial sources of carbon emissions, improving energy efficiency is a critical pathway for low-carbon transition of the cement industry. Based on the First Law of Thermodynamics, this paper further introduces the exergy analysis method derived from the Second Law of Thermodynamics to investigate the energy efficiency characteristics of the cement clinker pyro system, aiming to provide a novel theoretical analytical tool for energy conservation and carbon reduction. By shifting the analytical perspective from the "quantity" to the "quality" of energy, this study systematically reveals the exergy balance distribution within the cement clinker pyro system and establishes a standardized methodology for exergy efficiency calculation and analytical procedures. Taking a pyro system of the typical cement clinker line as the research object, an empirical exergy efficiency analysis is conducted using thermal calibration data. The results indicate that the exergy efficiency of the cement clinker pyro system is considerably lower than its thermal efficiency, and among the exergy output terms, "other outputs" account for the largest proportion. The output structure of the exergy balance differs significantly from that of the conventional heat balance, reflecting the irreversible losses inherent in combustion and heat transfer processes. Further analysis reveals that, compared with five-stage or six-stage preheaters, the seven-stage preheater can effectively enhance gas-solid heat exchange and improve the reversibility of heat transfer, thereby substantially reducing exergy losses and improving system energy efficiency. However, the overall design of the cement production line should also take into account comprehensive considerations such as raw material and fuel moisture drying, denitrification configuration, and alternative fuel utilization. The exergy-based analysis presented in this paper provides both a theoretical foundation and a quantitative methodology for achieving substantial energy conservation and carbon emission reduction in the cement industry.

 In high-altitude areas with low air density and low oxygen content, the pulverized coal burnout rate in cement clinker burning systems is lower and the required process air volume is significantly higher than in plain areas and making it considerably more challenging to meet the Grade I energy consumption limit specified in GB 16780-2021. A 5 500t/d cement clinker production line at an altitude of over 2 200m suffered from issues such as low heat exchange efficiency in the preheater, high outlet temperature of the C1 cyclone, insufficient calciner volume, high system resistance, and excessive comprehensive energy consumption per ton of clinker. Through an integrated application of technical measures — upgrading the five-stage preheater to six-stage, expanding the calciner, enlarging the throat of the kiln chamber, replacing the entire tertiary air duct, retrofitting the kiln bag filter and hot air ducts for pressure-drop reduction, and installing high-efficiency energy-saving fans — the specific standard coal consumption per ton of clinker after the renovation was better than the Grade I energy efficiency target. The annual savings amount to 8.58×10³t of standard coal, corresponding to a CO₂ emission reduction of 2.145×10⁴t, and electricity savings of 7.178×10⁶kW·h, demonstrating remarkable energy-saving and carbon-reduction benefits. This provides a replicable engineering example for improving the energy efficiency of cement clinker production lines in high-altitude regions.

 Due to the high sulfur content of raw materials and fuels in some domestic cement clinker production lines, the SO₂ concentration of kiln-tail flue gas far exceeds the ultra-low emission limits, so it is urgent to equip the production lines with high-efficiency desulfurization devices. Under such circumstances, the limestone-gypsum wet desulfurization system has become the mainstream environmental-protection technology for high-sulfur working conditions in the cement industry, benefiting from its advantages such as desulfurization efficiency ≥95%, strong adaptability to high-sulfur flue gas, and resource utilization of by-product gypsum. Combined with the production characteristics of complex flue-gas components and frequent working-condition fluctuations caused by co-disposal of solid waste in cement kilns, this paper systematically illustrates the reaction mechanism, system composition and control requirements of key process parameters for the limestone-gypsum wet desulfurization system. The causes of typical faults in practical projects are analyzed, including excessive moisture content of gypsum, fire risk during anti-corrosion material construction, water balance disturbance, slurry poisoning in desulfurization tower, and gypsum rain deposition at kiln tail. Optimized technical schemes are put forward, such as upgrading gypsum dehydration process, adopting duplex stainless steel clad plate for anti-corrosion treatment, implementing intelligent flushing control coupled with zero-liquid-discharge of wastewater, pretreating alternative fuels plus flue-gas moisture recovery, and reconstructing multi-stage composite demister. These schemes can provide engineering guidance for stable operation and maintenance and ultra-low emission upgrading of wet desulfurization systems in cement enterprises.

The cement industry, characterized by high-energy consumption and high carbon-emissions,increasingly utilizes combustible solid waste as a coal substitute to implement energy-saving and carbon-reduction policies and reduce production costs. This study details the implementation and optimization of a 5t/h waste textile direct-feeding system on a 4 800t/d new dry process clinker production line. To address operational challenges such as material blockage, dust accumulation in the tertiary air duct, and low Thermal Substitution Rates (TSR), a comprehensive process optimization was conducted. Key measures included the installation of a remote-controlled overhead crane and a four-stage dispersing device, optimization of the feeding-injection position of the precalciner, and stringent control of harmful components in the raw waste. Combustion characteristic analysis indicated that while waste textiles have a lower ignition temperature than pulverized coal, they exhibit a longer burnout time. By shifting the injection point from the tertiary air duct elbow to the lower oxygen-lean zone of the precalciner, the hidden danger of material accumulation in the tertiary air duct was completely eliminated, enabling stable 24h continuous operation. Consequently, the TSR increased from less than 2% to 2.5%. Industrial trials demonstrated the consumption of 4 500t of waste textiles without compromising clinker strength or free lime (f-CaO) content. This initiative resulted in a saving of 2 864t of raw coal, a reduction of 858t in CO₂ emissions, and fuel cost savings exceeding CNY 2.8 million. This retrofit, characterized by low investment and high adaptability, provides a viable engineering reference for the co-processing of waste textiles in similar cement production lines.

Spalling and pitting crater defects on rotary kiln support rollers are recurring equipment failures that severely disrupt the continuous and stable operation of cement production lines. Targeting a pitting crater defect with a depth of 40mm and an area of 300cm² on the support roller of a ?4.0m×60m rotary kiln at a cement plant, this paper develops an integrated online surfacing repair process. A302 stainless steel electrode is selected for the process. The integrated repair workflow covers pre-weld surface treatment, multi-layer temperature-controlled surfacing, and post-weld in-situ turning and grinding. Benefiting from the cold-work hardening effect formed under long-term roller operation, the surface hardness of the repaired area rises from 23.5HRC to 40.5HRC after three months of service, which is close to the hardness of the roller base metal. One year of post-repair operational monitoring data indicates that the roller surface temperature remains steady at 46°C~105°C, and the vibration amplitude of the rotary kiln shell is controlled between 10~55μm. All measured parameters stay within safe limits, and no secondary spalling occurs. Compared with the conventional offline repair method, this online solution cuts the repair duration by approximately 50% and slashes repair costs by roughly 90%, while drastically mitigating production losses caused by shutdowns. Field application verifies that this integrated online repair method delivers both outstanding emergency construction efficiency and reliable long-term service performance, offering a viable technical solution for remediation of identical defects on rotary kiln support rollers.

 This paper analyzes the main causes of material silo blockage, including high moisture content of raw materials, unreasonable structural design of silos, large friction coefficient of silo walls, and lack of external driving force to promote material flow. This paper compares the inherent limitations of traditional blockage treatment measures, including material moisture control, widening of discharge openings, laying resin plates on silo walls, installation of silo wall vibrators and manual blockage cleaning.The paper focuses on the structural working principle, key points of installation and commissioning, and common trouble-shooting methods of the hydraulically driven silo blockage dredging machine. Field application results show that the dredging machine adopts hydraulic drive to realize reciprocating motion of material rakes, which automatically loosens materials and breaks material arches, and can completely replace manual silo cleaning operation.After application, the cement mill downtime caused by silo blockage was reduced from 50% to 0%, and the frequency of manual blockage clearing per shift fell from 5 to 0, which greatly improves production continuity and on-site operation safety.

A 5 000t/d cement clinker production line is equipped with a double closed-circuit combined cement grinding system composed of a ?4.2m×13m ball mill and HFCG140-80 roller press. The long-term adoption of the general grinding media charge scheme prioritizing throughput improvement results in high unit power consumption and poor economic operation performance of the system. This paper carries out systematic optimization on the grinding media charge and gradation of the supporting ball mill through a combination of theoretical calculations and field industrial tests. Firstly, the gradation remained unchanged while the grinding media charge of the first and second chambers was adjusted stepwise. Correlation curves between total media charge, system throughput and power consumption were drawn to determine the optimal charge interval. Secondly, aiming to solve the difficulty in cement specific surface area control after reducing total media charge, the average ball diameter of the first chamber and the specification of steel cylpebs in the second chamber were both reduced to boost fine grinding efficiency.After optimization, the total grinding media charge was cut from 210t to 193t, and the system throughput remained stably above 175t/h. The unit power consumption of cement decreased from 26.68kW·h/t to roughly 24kW·h/t, achieving an annual electricity saving of about 230×10⁴kW·h. Meanwhile, the grinding media loss dropped from 20g/t to approximately 15g/t, and the operating current of auxiliary equipment declined by 5%~10%. This optimization scheme can serve as a practical reference for realizing energy-saving and economic operation of double closed-circuit combined grinding systems via adjusting grinding media charge and gradation.

 The original DCS alarm system of the grinding system in a cement production line suffers from imperfect architecture, multiple monitoring blind spots. Operators have long relied on manual experience to judge equipment operating conditions, resulting in delayed fault responses. Accordingly, a voice alarm system was developed and applied to this production line. The system was implemented in three phases: first, sorting out and optimizing DCS operational interlocks and adding monitoring-point sensors; second, completing system development and hardware deployment; and finally, carrying out continuous iterative optimization. Technically, multi-source data such as equipment vibration, temperature, electric current and material level are accurately collected via edge computing. A multi-dimensional alarm classification system and priority scheduling mechanism are established, and a speech-synthesis module is integrated to realize dual voice broadcast via onsite columnspeakers and the central control room. Feature-recognition models are built for typical abnormal working conditions such as roller press material collapse and mill over-filling, which automatically trigger voice alarms and link interlock protection. Environment-temperature adaptive threshold adjustment is introduced for key parameters (e.g., bearing temperature) to reduce false alarms. After commissioning, the number of alarm items decreased from 299 to 184. The false-alarm rate was lower than 1% during 60d online operation. The system realizes the transformation from manual on-site watch-keeping to online monitoring, from empirical judgment to data-driven identification, and from audible?visual prompts to voice broadcast. It effectively improves fault-response efficiency and production stability.

Aiming at the prominent problems of large calculation errors, low design efficiency and poor economic performance in traditional manual preliminary selection of belt conveyors, an intelligent design system for preliminary selection of belt conveyors has been developed in accordance with GB 50431-2020 Technical Standard for Belt Conveyor Engineering. Core modules including parametric digital modeling, dynamic parameter verification and multiobjective optimization are integrated into this system. Supporting databases are established, covering property database of 32 types of typical industrial materials and a complete equipment component database. A dynamic correction algorithm for belt speed-angle of repose is innovatively introduced to realize automatic verification of design parameters such as belt width, filling rate and inclination angle for hundreds of belt conveyors, as well as accurate matching and selection of motors. Engineering applications show that the error of parameter verification is reduced to 0.5%, the efficiency of batch selection is increased by tens of times compared with manual design, and the average project cost of equipment is reduced by 10%. It effectively addresses the engineering dilemma that selection accuracy, efficiency and cost cannot be balanced in the bidding and tendering phase. The development of this system fills the gap of domestic preliminary selection systems for belt conveyors in the field of rapid engineering design, and provides an efficient and reliable technical tool for intelligent design of bulk material handling equipment.

 With the increasing application of Building Information Modeling (BIM) technology in cement engineering project design, Revit, as the core modeling software, relies heavily on plugin secondary development for functional extension. However, with the rapid growth in plugin quantities and rapid version iterations, traditional manual deployment approaches have exposed problems such as chaotic version management, difficulties in batch deployment, coarse-grained permission control, and data security risks. To address these challenges, this paper designs and develops a Revit plugin management system that adopts a layered hybrid architecture to achieve unified plugin access and secure management. The paper proposes the RPRM (Revit Plugin Resource Meta-model) resource description model, which uses a four?tuple structure to define the basic information, dependencies, runtime entry points, and interface rendering information of plugins, providing a unified data foundation for full lifecycle plugin management. By deeply integrating the Revit API, the system implements automatic plugin installation, dependency resolution, silent updates, and exception rollback mechanisms. Engineering applications demonstrate that the system, as an enterprise-level BIM public toolchain platform, has been operating stably for many years, cumulatively managing nearly 100 in-house developed plugins covering full-discipline forward design business processes, with monthly click volumes exceeding 20 000. It has effectively resolved Revit plugin conflicts and version incompatibility issues, significantly improving plugin management efficiency and BIM data security.

Cement production is a typical process industry production, and its DCS process control system is required to operate continuously for a long time with high reliability requirements. Aiming at the problems existing in the physical server architecture of traditional DCS systems, such as low hardware resource utilization, long fault recovery period and poor system scalability, this paper takes the DCS system of a cement production line as the retrofitting object. Based on the complete server virtualization solution of VMware vSphere and the vCenter centralized management and control platform, a virtualization architecture retrofitting scheme is established for the DCS system. In this scheme, all physical computers of the original DCS system are migrated to the virtualization platform and replaced by 5 virtual machines for operator stations and 1 virtual machine for the engineer station. Thin clients are deployed as frontend interactive terminals, thereby reducing virus risks at the source. Nonstop operation of the DCS system is guaranteed by means of resource pooling, high availability architecture and distributed storage. The implementation results show that the retrofitted DCS system achieves significantly improved hardware resource utilization, convenient and efficient virtual machine deployment and expansion, and greatly enhanced operation and maintenance efficiency. The hardware investment is reduced by approximately CNY 143 800 compared with the traditional scheme, thereby providing a reusable paradigm for similar system retrofitting projects.

 Aiming at the practical problems of frequent coating and delayed blockage prediction of preheaters when co-processing high-sulfur alternative fuels in cement clinker production, based on the full-process digital platform of a 5 000t/d cement production line, an intelligent early warning system for preheater coat formation was developed.By integrating multi-source data from raw materials, fuel, calcination process, and quality inspection, and combining infrared thermal imaging for full-area temperature measurement with quantitative modeling methods, the system establishes a "comprehensive coating index" model for the preheater to uniformly quantify the overall coating degree and its evolution trend, enabling real-time root-cause analysis of key factors triggering coating. Engineering application results show that the system can achieve early prediction of coating risks and quantitative forecasting of coating thickness. Since its implementation, under conditions of using 3.7×10⁴t of high-sulfur carbon black as alternative fuel, no preheater shutdowns due to coating-induced blockage have occurred. In addition, the measured temperature data provides data support for refined health management of refractory linings. This system possesses great promotion value for coating risk control when cement plants co-process alternative fuels containing sulfur, chlorine, alkali and other harmful components.