At present, some domestic large coking plant desulfurization process generally uses ammonia desulfurization technology (HPF technology). In the process of desulfurization, desulfurization liquid when the salt concentration reaches a certain value, the desulfurization efficiency will be greatly reduced, as desulfurization desulfurization liquid waste. At this time, must discharge part of the desulfurization waste add new desulfurization liquid can continue. The resulting FGD is generally taken simple treatment before discharge, not only causing serious pollution to the environment, but also a waste of industrial raw materials, increase the production cost of enterprises. The desulfurization wastewater treatment technology came into being put salt, this technology is put into use, in energy saving and emission reduction but also realize the recycling of resources.

According to statistics Chinese Coking Industry Association, coking plant with an annual output of 1 million tons of coke, desulfurization waste generated every day for 30 to 40 tons, the amount of the FGD coke production plant’s daily production of more than 10 thousand tons, annual production of 3 million tons to 4 million tons desulfurization wastewater. How to make a good salt treatment and comprehensive utilization of desulfurization wastewater has been the environmental protection problem coal enterprises.

The traditional technology brings new trouble

“Coking Desulfurization Waste Liquor salt industry was a water saving and environmental protection industry, but because of the traditional backward technology and embarrassment. Coking Desulfurization Waste Liquor salt technology needs to be upgraded.” Recently, there are seven or eight continuous coking enterprises reflect the drawbacks of traditional technology brings new trouble to coking enterprises.

Shandong Rongxin Chemical Co. Ltd., Shandong Dongchang Coking Co. Ltd and Inner Mongolia Wuhai Desheng Coal Coking Co., Ltd., Henan Yulong coking Coking Co. Ltd., Shaanxi Huangling Wei Tian Chemical Co. Ltd. Jiangsu responsible person, FGD they invested nearly 10 million yuan of salt project, although extraction from desulfurization waste liquor from the ammonium thiocyanate, Ammonium thiosulfate 3 kinds of chemical products and ammonium sulfate, ammonium thiosulfate but due to the selling price, sometimes even no market, it is difficult to translate into other products, thus forming a new enterprise burden, company to hire money away, otherwise it will cause two pollution and fines.

To be the depth of the use of waste

China coal chemical Specialized Committee experts, technology consultant in Shanxi Jinyang Coal Coking Group Company Hu Yizhi believes that FGD domestic coking enterprises are almost no depth of use, many coking enterprises as the coal blending water spraying in coal heap. Although this method solves the desulfurization waste liquid to the surface does not seem to waste liquor, but it does not fundamentally solve the problem.

Hu Yizhi said, because of the desulfurization waste coal into coke oven, at high temperatures will still be converted into sulfur dioxide and hydrogen sulfide containing sulfide, which will eventually have to return to the desulfurization wastewater. Thiocyanate ion contained in the desulfurization waste water has strong sterilization effect, not for biochemical treatment, so the traditional way has great disadvantages, not only affects the quality of coke, groundwater pollution, and increase the energy consumption of coking, seriously restrict the long-term stable operation and sustainable development of enterprises.