高炉煤气中HCl脱除研究现状与展望

Status and prospects of research on HCl removal from blast furnace gas

  • 摘要: 为明确高炉煤气中的氯元素对高炉附属设备的影响,本文论述了高炉煤气中氯元素的来源和赋存形态,归纳了氯离子对高炉TRT叶片、煤气管网和附属设备以及热风炉耐火材料所造成的积盐结垢、腐蚀等危害. 针对高炉煤气中氯离子所造成的危害,在不改变高炉炼铁工艺的前提下,从高炉入炉原料源头控制,改善高炉操作工艺、开发管道防腐和TRT阻垢技术,TRT后喷碱脱氯以及TRT前干法脱氯这几个方面进行了深入研究. 通过对上述工艺优缺点的对比和实验室模拟分析,提出了以TRT前管道喷吹脱氯为主,关键设备防腐为辅,二者相结合的工艺,将是今后高炉煤气脱氯的重点研究方向.

     

    Abstract: To address the harm caused by chlorine ions in blast furnace gas, and without altering the fundamental blast furnace ironmaking process, this article conducts an in-depth study focused on various strategies. These include controlling the chloride content in raw materials entering the blast furnace, optimizing the blast furnace operation process, developing pipeline corrosion and blast furnace top gas recovery turbine unit (TRT) scale inhibition technologies, applying alkali dechlorination after TRT, and implementing dry dechlorination before TRT. Regarding chloride source control, it is challenging to significantly reduce HCl generation due to the constraints of the raw materials supplied to the blast furnace and the limitations of the production process. Improving the blast furnace operation process, such as reducing the reduction of roof watering, cannot fully prevent subsequent pipeline corrosion. It may also lead to several adverse consequences, including increased heat energy loss, higher furnace dust production, a shortened service life of the blast furnace roof equipment, and a decline in the sealing performance of the furnace roof. Pipeline anticorrosion technology can extend the pipeline lifespan to some extent, but it is costly and cannot entirely resolve the corrosion issue. Although TRT scale inhibition technology can slow the accumulation of salt scaling on the blades, prolonged use may lead to the formation of pharmaceutical scales. Additionally, the high cost of this technology presents a significant economic burden for large-scale implementation. While post-TRT alkali spray dechlorination effectively protects gas pipelines and equipment after the alkali spray tower, it does not address salt buildup on the TRT blades or the corrosion of gas pipelines between the TRT and the alkali spray tower. This approach may be more suitable for specific applications, such as when space allows and wastewater treatment facilities are available. Fixed-bed dry dechlorination technology is limited by the air velocity of the dechlorinating agent, resulting in the need for large dechlorination towers and frequent replacement of the agent. Additionally, there is a pressure drop in the fixed bed, which can impact the power generation of the TRT. In contrast, pipeline blowing dechlorination allows for flexible adjustment of the blowing volume and pressure of the dechlorinating agent based on actual chlorine content and process requirements, enabling precise control of the dechlorination effect. The pipeline blowing system offers a high degree of automation, simple operation, and easy maintenance, making it suitable for a variety of working conditions. The article also examines the impact of HCl in blast furnace gas on fine desulfurization hydrolysis catalysts, highlighting that HCl causes deactivation of the hydrolysis catalyst, which in turn reduces its effective surface area and catalytic activity. Therefore, reducing HCl content in the gas is crucial for improving the service life and efficiency of the hydrolyzer. Finally, the article proposes directions for future research, including optimizing the performance of dechlorinating agents, reducing costs, and developing more environmentally friendly dechlorination technologies to ensure cleaner use of blast furnace gas and support the sustainable development of the steel industry.

     

/

返回文章
返回