Pilot study on coke oven flue gas injection desulfurization using highly active modified calcium hydroxide desulfurizer

Abstract

Calcium hydroxide injection desulfurization has attracted extensive attention because of its low cost and recyclable characteristics. The modified calcium hydroxide was prepared on the basis of the digestion of calcium lignosulfonate (wood calcium) aqueous solution with ethanol and used in the pilot test of flue gas injection desulfurization of the coke oven. The injection desulfurization experiment was carried out with calcium hydroxide modified by 50% ethanol and 20% ethanol+0.5% wood calcium. It was found that the injection desulfurization efficiency of the two modified calcium hydroxide was better than that of the unmodified calcium hydroxide under the same injection conditions. The desulfurization efficiency of 20% ethanol+0.5% calcium hydroxide modified by wood calcium can reach more than 93.7% under the condition of 2 and 5 times calcium to sulfur ratio. The XRF analysis of desulfurization product showed that the content of S element in unreturned desulfurization ash was only 1.28%, which increased to 4.46% after 5 times of return. BET results showed that the specific surface area of the returned desulfurization ash decreased from 35.115m²/g to 10.256m²/g and the pore volume decreased from 0.103cm³/g to 0.0433cm³/g.