The pyro system of a 5 500t/d cement clinker production line had problems such as too high pressure loss at the outlet of the C1 cyclone, the inverted temperature of the calciner and the C5 cyclone, the too large consumption of denitrification ammonia, and the low heat recovery efficiency. By technical measures including expanding the volume of the calciner, expanding the space for decomposition, combustion, denitrification, replacing the cone of the C4 cyclone with a crooked cone, using the burner with a new swirl type, optimizing the splash device, improving the cyclone structure, and using nanometer heat insulation as well as the fourth-generation grate cooler, it reduced the coal consumption, power consumption and denitrification ammonia consumption, and the annual comprehensive economic benefit can reach more than 20 million yuan.

There were lots problems in the 4 500t/d cement clinker production line such as high coal consumption, large resistance of the pre-calcining system, low capacity, poor system heat exchange, serious coating, low cooler efficiency, and large consumption of denitrification ammonia. Combined with production practice and process design research, the expansion of calciner volume, the expansion of the ventilation area at the inlet of the cyclone, the optimization of riser duct of the kiln inlet chamber, the resistance reduction of the preheater system, the replacement of the high-efficiency splash box and the air lock valve, and the use of low-nitrogen staged combustion technology, the fourth-generation high-efficiency grate cooler are adopted. The negative pressure at the outlet of the C1 cyclone is reduced to 5 000Pa, the NOX concentration is controlled at about 450mg/m3 before the treatment of the SNCR system, and the clinker temperature out of the grate cooler is 65℃+ ambient temperature, the physical coal consumption is reduced to 136.5kg/t.cl, the annual comprehensive economic benefit can reach to 33 million yuan, and the effect of energy-saving transformation is remarkable.

This paper introduces the transformation plan of the fixed grate bed, movable grate bed, air chamber, ash hopper discharge seal and other components of the third and fourth generation grate coolers. The cooling efficiency of the fixed grate bed is effectively improved by adopting the vertical control flow fixed grate bed at the high temperature blanking end, partitioning the fixed grate bed, configuring the quenching grate plate with strong penetrating power, and installing electric butterfly valves in the air supply duct to achieve the rapid cooling of clinker. At the same time, by using longitudinally arranged ventilation grooves, the clinker particles on the movable grate bed can be cooled from multiple directions to form a "cross-flow cooling grate bed", and the thickness and moving speed of the clinker layer can be effectively controlled. After the transformation, when the fan load rate in the heat recovery area is greater than 95%, the secondary air temperature is stable above

1 100℃, the clinker temperature of the grate cooler is less than 65℃ + ambient temperature, the clinker strength is increased by 2~4MPa, and the material fineness is improved.

The characteristics of sulfate-resistant cement, the composition of clinker minerals and the grindability of sulfate-resistant cement were analyzed. The application of TRMK3621 roller mill final grinding system in grinding sulfate-resistant cement was introduced. TRMK3621 type roller mill changes the traditional flat disc structure into a slightly angled swash plate, increases the width of the grinding area, and has strong material adaptability. Sulfate-resistant cement is more difficult to grind than ordinary Portland cement. TRMK3621 roller mill is used to grind sulfate-resistant cement clinker. The system runs stably and is easy to operate. The output is over 95t/h, the specific surface area is 330m2/kg, and the power consumption is 32kW·h/t.

 The cement grinding system adopts the double-circle flow process of "roller press + ball mill". During the operation of the system, the pressure loss of the cyclone cylinder is high, the water vapor in the discharge air duct is high, and the air intake of the powder separator is uneven. From 2020 to 2021, the system has been adjusted and optimized many times, the original six-barrel combined cyclone was updated to a single-barrel high-efficiency cyclone, and the O-Sepa type high-efficiency powder separator was replaced with an N-U type high-efficiency powder separator. The position of the process pipes such as the exhaust air duct and the outgoing air duct has been adjusted. After the renovation, the system resistance decreased, the dust collection efficiency of the cyclone was increased to 95.7%, the power consumption of the process was reduced by 2.4kW·h/t, and the power consumption of grinding was reduced from 0.65kW·h/t before the renovation to 0.40kW·h/t .

This paper introduces the importance of oil lubrication condition monitoring and oil monitoring technology in cement production. By analyzing the physical properties, chemical composition and wear of lubricating oil of cement production equipment, such as lubricating oil kinematic viscosity, moisture, acid value, pollution degree, PQ index, ferrography, anti-emulsification performance, element spectrum monitoring, etc., it is possible to effectively judge the production equipment operating status. Combined with production examples, the process of using oil monitoring technology to judge the operation status of cement production equipment is introduced.

This paper introduces the structural design of the EPC project of a cement plant in Africa. Through studying the contract, it clarified the requirements for the structural design part and determined the design principles. It did a good job in design subcontracting management, formulated a drawing approval plan, and improved the review efficiency of project drawings. Combined with the previous design work experience and the adoption of the limit design method, the design and construction costs are reduced on the basis of ensuring the safety of the structure.

This paper analyzes the high energy consumption and high cost operation problems of the company's cement clinker production line, introduces a series of energy saving and consumption reduction measures taken in the preheater system, main fans, denitrification system, etc. It also carried out management and control measures such as the "five stabilities to one stability”, advanced equipment to eliminate hidden troubles, and "running and leaking" etc. After the improvement, in 2020, the energy consumption, quality and other indicators of cement kilns reached the best level in history. The coal consumption had be reduced by 5.96kg/t compared with 2019, and the cement power consumption had be reduced by 8.29kW·h/t compared with 2019. The significantly effect of energy saving and consumption reduction was achieved. 

 In a cement kiln co-processing solid waste project, the incineration flue gas was sent to the calciner for collaborative purification. During the operation of the raw meal mill, the HCl emission concentration in the kiln preheater flue gas could usually meet the national standard limit; however, during the shutdown stage of the mill, the HCl emission concentration in the flue gas of the preheater frequently exceeded the limit value of the national standard. By adopting the online HCl removal technology of spray drying and deacidification, and using slaked lime powder to remove HCl to transform the original system, the stable emission of HCl in the flue gas of the cement kiln co-processing kiln is realized.

By adjusting the quality of raw and fuel materials, strengthening the control of cement clinker production process, optimizing the clinker batching plan, and adjusting the clinker production process operation, the 3d compressive strength of clinker was increased from 28.5MPa to 31.0MPa, and the 28d compressive strength was increased from 52.0MPa was increased to 57.0MPa, the proportion of clinker was reduced from 85% to 81%, the quality of cement clinker was improved, and good economic benefits were achieved.

Carbide slag is used as raw material to produce cement. Because the content of harmful components of chloride ions and sulfur-alkali ratio of calcium carbide slag are much higher than those of limestone cement production line, the crusting of preheater and precalciner system has always been a major technological problem affecting the stable operation of rotary kiln. By adopting the sulfuric acid cleaning process instead of the hydrochloric acid cleaning process, the chloride ion content and the sulfur-alkali ratio in the raw materials are reduced; by controlling the combustion of pulverized coal, the local high temperature of the precalciner is avoided. After such measures, the skinning of the system has been reduced by more than 60%, realizing the efficient and stable operation of the system.

The main reasons affecting the fluidity of P·O42.5 cement slurry were analyzed, and measures to improve the fluidity of P·O42.5 cement slurry were proposed. It was adding 3% coal gangue for raw meal batching; adjusting the raw materials and control indicators for cement batching, using modified phosphate gypsum and desulfurized gypsum in a 1:1 combination; optimizing and adjusting the grinding process of the open-circuit mill and improving the feeding of the powder separator. In this way, the specific surface area and temperature of the grinding cement were reduced, and the management of cement in and out of the warehouse was improved.