Gao Chunlei, Zhang Linmin, Song Xudong, Cao JinSheng, Guo Qinghua, Yu Guangsuo
Institute of Clean Coal Technology, East China University of Science and Technology Shanghai 200237 China.
Yankuang Energy Group Co., Ltd Shandong 273500 China.
RSC Adv. 2025 Jun 25;15(27):21731-21741. doi: 10.1039/d5ra02794b. eCollection 2025 Jun 23.
As a core process in the coal chemical industry, entrained-flow gasification technology promotes clean energy conversion by efficiently producing syngas. In industrial applications, radiant syngas cooler (RSC) is usually adopted to recover high-temperature syngas and slag waste heat from the gasifier outlet to improve system heat utilization. However, the ash deposition and slagging behavior in RSC can lead to a decrease in heat transfer efficiency and limited production capacity, becoming a key bottleneck, restricting technological development. In this work, the ash slags in the critical areas (radiation screen top 25 m, 25/20/15 m around spray water, floating ash on water-cooled wall, and boiler bottom 0-1 m) in the RSC were taken as the research object, and its elemental composition, ash chemical composition, mineral evolution, and high-temperature melting, and crystallization behavior were systematically analyzed. The results showed that after rapid cooling by RSC, some carbon particles in the fly ash carried by high-temperature syngas terminated the gasification reaction due to insufficient temperature, forming residual carbon, resulting in a higher carbon content in the floating ash of the water-cooled wall. The sulfur element was primarily enriched in the middle area of the RSC (floating ash on the water-cooled wall and 15 m around spray water). Mineral evolution analysis showed that alkaline oxides (CaO, FeO, NaO) and acidic oxides (SiO, AlO) in the ash slags inside the RSC underwent low-temperature eutectic reactions to form low melting point minerals, such as nepheline, anorthite, augite, and melilite. The higher content of ZnO in the ash slag at 15 m around the spray water reacted with CaO and SiO to generate the refractory mineral CaZnSiO, resulting in an increase in its melting temperature. observation showed that all the ash slag samples displayed three stages of "shrinkage-melting-flow". Due to the formation of the refractory substance CaZnSiO in the ash slag at 15 m around the spray water during heating, its melting temperature was high and required a higher temperature to complete the flow. During the cooling and crystallization process, some interlaced rod-like crystals and a few square crystals were mainly precipitated in the slag.
作为煤化工行业的核心工艺，气流床气化技术通过高效生产合成气来促进清洁能源转化。在工业应用中，通常采用辐射式合成气冷却器（RSC）从气化炉出口回收高温合成气和炉渣余热，以提高系统热利用率。然而，RSC中的积灰和结渣行为会导致传热效率降低和生产能力受限，成为制约技术发展的关键瓶颈。在这项工作中，以RSC关键区域（辐射屏顶部25m、喷水周围25/20/15m、水冷壁上的浮灰以及锅炉底部0 - 1m）的灰渣为研究对象，系统分析了其元素组成、灰化学成分、矿物演化以及高温熔化和结晶行为。结果表明，高温合成气携带的飞灰经RSC快速冷却后，部分碳颗粒因温度不足终止气化反应，形成残碳，导致水冷壁浮灰中碳含量较高。硫元素主要富集在RSC的中部区域（水冷壁上的浮灰和喷水周围15m处）。矿物演化分析表明，RSC内部灰渣中的碱性氧化物（CaO、FeO、NaO）和酸性氧化物（SiO、AlO）发生低温共熔反应，形成霞石、钙长石、辉石和黄长石等低熔点矿物。喷水周围15m处灰渣中较高含量的ZnO与CaO和SiO反应生成难熔矿物CaZnSiO，导致其熔化温度升高。观察表明，所有灰渣样品均呈现“收缩 - 熔化 - 流动”三个阶段。由于喷水周围15m处灰渣在加热过程中形成难熔物质CaZnSiO，其熔化温度较高，需要更高温度才能完成流动。在冷却结晶过程中，渣中主要析出一些交错的棒状晶体和少量方形晶体。
