Cement plants use waste heat to maximize profits
Date：2019-08-30 16:09 Source：cementepcViews:
The cement industry is undergoing rapid structural adjustment and high productivity growth. Due to the progress in production technology and equipment, the consumption of electricity and coal is much lower than that of the original shaft kilns and the new dry production lines in the initial stage.
1. Increase the generating capacity of waste heat
(1) does not affect the production of clinker;(2) no increase in heat and power consumption of clinker production;(3) do not change the central fuel drying heat source in the production of clinker;(4) do not change the clinker production process and equipment.This "four non-principles" has great practical significance in the primary stage of the development of pure low-temperature waste heat power generation in China, but the design is too conservative, many early-designed power generation system tons of clinker generation index is lower than 30 kWh/t, affecting the standard of waste heat power generation system.In order to increase the power generation of waste heat, the kiln operator will try to recover as much as possible the clinker heat, increase the grate cooler air, and then increase the kiln head exhaust fan frequency to ensure the negative pressure.It no longer focuses on the amount of heat recovery, but pays more attention to the thermal efficiency. That is to say, from increasing the cooling air of clinker in the past to reducing the cooling air volume, reducing the frequency of the three-stage fan and the kiln head exhaust fan of grate cooler, increasing the temperature of exhaust gas by 100 ℃ to ensure the operation at 420 ℃.The quality of superheated steam of other electric power is greatly improved, the power generation of tons of clinker reaches 36 kWh/t, the monthly average power generation of tons of clinker increases by more than 7 kWh/t, and the energy efficiency is increased by more than 24%.At the same time of obtaining better economic benefits, it maximizes the wear of kiln head AQC boiler and the electricity consumption of clinker system, so as to achieve the purpose of stable and economic operation of kiln and waste heat power generation systems.
2. Waste heat power generation promotes peaking production and improves economic benefits of waste heat power generation
Cement plant is a large power consumption, cement plant continuous operation of equipment is mainly rotary kiln system, reasonable adjustment of operation, raw material grinding can also avoid peak electricity.Therefore, if the power generation operation during peak power period is strengthened and the power generation is increased, the cost of electricity consumption will be greatly reduced, creating benefits for enterprises.The main measures are as follows :(1) increase the statistics of waste heat generating capacity during peak and normal power periods, intensify the assessment in this range, reward and punish heavily, and guarantee the mechanism;(2) reduce the air used for clinker cooling, further increase the inlet temperature of AQC boiler, and increase the power generation;(3) reduce the operating load of equipment during peak power period, and selectively stop the mill, crusher, auxiliary machine and other equipment according to the load.Through operation observation, it can basically achieve the goal of self-sufficiency in peak electricity consumption.
3 isolated network operation, improve the continuous operation of kiln system
cut off the network before power failure, do a good job of load control, to prevent too high too low fluctuations caused by voltage fluctuations.
Specific as follows:
(1) by appropriately reducing the feed quantity of the kiln, the kiln condition is kept in a light state and the thermal anti-interference ability of the kiln system is enhanced;
(2) it is strictly forbidden to adjust grate velocity and cooling fan frequency of grate cooler;
(3) disconnect all compensation cabinets in the power room;
(4) closely monitor the balance between power generation load and electricity load. If the load is too high or too low, adjust it by frequency conversion of high voltage motor of cement mill and kiln tail exhaust fan to balance the power grid load and ensure the power grid frequency of 50 Hz.
4. To summarize
The operation and management of the waste heat power generation system no longer focuses on the amount of heat recovery, but pays more attention to the thermal efficiency. That is to say, the cooling air volume is adjusted from increasing the cooling air of clinker in the past to reducing the cooling air volume, reducing the frequency of the three-stage fan and the kiln head exhaust fan of grate cooler, and increasing the exhaust gas temperature by 100 ℃ to ensure the operation at 420 ℃.The quality of superheated steam of other electric power is greatly improved, the power generation of tons of clinker reaches 36 kWh/t, the monthly average power generation of tons of clinker increases by more than 7 kWh/t, and the energy efficiency is increased by more than 24%.
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