Adjusting the Primary Cooling of Coke-Oven Gas for Batch with Elevated Gas-Coal Content

Industrial experiments show that it is expedient to treat the recirculation loop in primary gas-cooling units with a corrosion and scale inhibitor based on zinc, phosphonate, and polymer dispersants, so as to eliminate salt deposits on the equipment surfaces and to prevent the solution of the heat-transfer surfaces. The effectiveness of such treatment is confirmed by calculating the quantity of deposited Ca2+ ions at different stages of the experiment. Treatment by the reagent at a rate of 5.0-6.6 kg/h (recalculated for CaCO3) prevents the formation of calcium deposits. In addition, the increase in the concentration of suspended material in the circulating water when the reagent is supplied indicates the formation of suspended adsorption complexes of calcium carbonate, which are not deposited on the heat-transfer surfaces. The results show that the temperature difference of the cooled gas and the cooling water in the primary gas-cooling units may be decreased by 1.0-1.5 degrees C. That compensates for the increase in enthalpy of the coke-oven gas, including the increase associated with the high content of gas coal in the batch.