Recovery method of blast furnace slag water residual heat and method thereof

Abstract

The invention discloses a recovery method of blast furnace slag water residual heat and method thereof. The recovery system of resudual heat includes a blast furnace slag system, a sedimentation tank, a hydrocyclone separator, a water pump, a heat exchanger, a steam turbine, a refrigerant condenser, a refrigerant pump. The recovery method is that applying bicirculating low temperature hot water generation system to recovery residual heat and penerating power. The specific process is: guiding the blast furnace slag water into the heat exchanger after preprocessing of impurity precipitation and transmitting heat to low boiling refrigerant; the low boiling refrigerant absorbing heat in the heat exchanger and entering the steam turbine for expansion of doing work; the refrigerant after doing wirk changing into low-pressure superheated steam, the low-pressure superheated steam entering the concenser to releast heat and changing into liquid refrigerant of low-temperature and low-pressure, then being sent to the heat exchanger by the refrigerant pump for absorbing heat, becoming the superheated steam again to push the steam turbine to do work. The invention can recovery residual heat of the blast furnace slag water and generate power, and reduce energy consumption in steel production; and reduce temperature of blast furnace slag water which is benefit to improve quality of blast furnace water slag and reduce discharge of sulphide in slag washing process.

Description

technical field [0001] The invention relates to a waste heat recovery and utilization technology, in particular to iron and steel metallurgy energy saving and secondary energy recovery and utilization. Background technique [0002] With the development of my country's steel industry and the rapid growth of steel production, resources, energy and environmental pollution have become restrictive factors restricting the sustainable development of my country's steel industry. At present, the annual output of pig iron in my country has exceeded 400 million tons. Every ton of pig iron produces 0.3-0.6 tons of blast furnace slag, and the annual output of blast furnace slag exceeds 120 million tons. The temperature of the liquid blast furnace slag produced in the ironmaking process is above 1400°C. Water quenching is generally used to granulate and cool the high-temperature liquid blast furnace slag to generate blast furnace slag suitable for a large amount of cement production. In...

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Problems solved by technology

In the process of water quenching, 8-12 tons of slag-washing water with a temperature of about 85°C is produced for every 1 ton of blast furnace slag. Except that some iron and steel enterprises in the north use a small amount of slag-washing water for heating in winter, a large amount of heat contained in it is lost in vain. , resulting in thermal pollution of the factory and the surrounding environment; blast furnace slag washing water is recycled, the higher the temperature, the more sulfides are discharged during the slag washing process, and the quality of blast furnace slag is worse

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