How to understand heat-recovery coke ovens?

Heat-recovery coke ovens do not have a chemical production system; the gas and tar produced are used as fuel in the coking process, and the heat from the waste gases generated during coking is recovered to generate electricity. Its products are coke, electricity, or steam. Its coke can be used as foundry coke.

Introduction to Clean Heat-Recovery Coke Ovens: Clean heat-recovery coke ovens consist of multiple coke oven units, heat-recovery devices, flue gas desulfurization and dust removal systems, as well as centralized exhaust emission towers； The production process involves ramming coal into the furnace, igniting it inside the furnace, undergoing secondary combustion, and operating under negative pressure ； A type of coking furnace that generates no coking wastewater during the continuous coking process, and enables effective recovery of waste heat as well as low-pollution emission of exhaust gases. Each coke oven bank consists of multiple coking chambers that can ignite each other, forming a coking production unit with a common flue for secondary combustion and connected to a heat recovery system. The coking chamber has the functions of heating, carbonizing, and quenching the coking coal in the same chamber. In the main combustion chamber, a lean-oxygen atmosphere is used to create separate layers for combustion and coking. It is connected to the overall flue system of the furnace through vertical flues on both sides, bottom flues, and smoke distribution flues, enabling secondary combustion under negative pressure; this creates a closed space in which the coking coal is heated from above, below, and from all four sides to facilitate coking ； The high-temperature flue gas resulting from secondary combustion during the coking process is used to recover waste heat in a waste heat boiler to generate steam, thereby utilizing its thermal energy. Typically, auxiliary generator sets are used for power generation; the exhaust gases resulting from heat recovery are purified through desulfurization and dust removal. Coking wastewater is purified using sedimentation processes before being reused in a closed-loop system, thereby preventing any discharge of coking wastewater. It represents a new type of large-capacity coke oven. Advantages of clean heat-recovery coke ovens: Compared with traditional large-scale coke ovens, clean heat-recovery coke ovens have the following advantages: 1. Improved comprehensive utilization of coal resources. For clean heat-recovery coke ovens, the proportion of coking coal used in the coal mixture should not exceed 20%–25%, while weakly caking coals and anthracite should account for at least 50% ； The proportion of coking coal used in the production of cast coke should not exceed 50%, while the proportion of weakly caking coal and anthracite should be at least 40%. Compared with traditional large-scale coke production methods, the proportion of weakly caking coal is **increased**, and anthracite can also be used in the coke-making process. Currently, coking coal resources are becoming increasingly scarce, which is conducive to conserving these valuable coking and fertilizing coal resources. In addition, fatty coking coal and low-cohesion coal have a significant price advantage, with a difference of at least 200 yuan per ton. This reduces the cost of coke; for a coking plant with a capacity of 600,000 tons, using coal from clean heat-recovery coke ovens can lower costs by over 48 million yuan per year, thereby significantly improving the economic efficiency of coke-producing enterprises. 2 Reducing environmental pollution contributes to the implementation of environmental protection efforts. Clean-type heat-recovery coke ovens operate with negative pressure in the carbonization chamber, with a negative pressure level of -1 OPa within the furnace; this helps to regulate the combustion atmosphere of the flue gases and prevents the release of atmospheric pollutants. Compared to traditional coke ovens that operate under positive pressure, this approach eliminates problems such as smoke leakage and fires, as well as the emission of atmospheric pollutants like benzene compounds that were produced by traditional coke ovens. As a result, the atmospheric conditions in coke plants are significantly improved. The cleaning-type heat-recovery coke oven quenching water is recycled in a closed loop, eliminating the discharge of wastewater. Compared to traditional large-scale coke ovens, it does not generate coking wastewater containing phenols, cyanides, and other substances as a result of subsequent production processes, thereby significantly improving the water quality in the area where the coking plant is located. 3 Coke product quality: Due to the use of large-volume ramming coking, the bulk density of the coking coal is 0.98 g/cm3. In addition, the increased use of weakly caking coals and anthracite other than coking coal facilitates better control over the ash and sulfur content in coke, resulting in higher-quality coke compared to that produced by traditional large-scale coke ovens. 4 Level of mechanization: The clean-type heat-recovery coke ovens achieve or exceed the level of mechanization of traditional large-scale coke ovens, enabling the mechanization of coal loading, coke extraction, coke quenching, and tamping in these ovens. The monitoring coverage rate for furnace temperature and furnace pressure in clean heat-recovery coke ovens should be 100%.

The conventional ones come with a chemical processing system! Heat-recovery coke ovens do not have a chemical production system!

The electricity conversion factor of 0.404 kgce/KWh means that 1 kilowatt-hour of electricity is equivalent to 0.404 kilograms of standard coal.