As of 7 PM on October 2, 2021, the Xinjiang Yihua gasification unit, built by CAS Hefei Coal Gasification Technology Co., Ltd. (“ZHGAS”), reached 200 days of continuous, safe operation on a single circulating fluidized bed (CFB) gasifier, setting a new record for continuous operation using high-alkali coal as feedstock.
High-alkali coal, rich in alkali metals such as sodium, potassium, calcium, and iron, is abundant in China—particularly in the Zhundong region of Xinjiang, where reserves are estimated at 390 billion tons. However, its low ash fusion point causes slagging and fouling issues that easily lead to coking and corrosion in gasifiers, severely limiting large-scale gasification and utilization of Xinjiang’s Zhundong coal. To address these challenges, ZHGAS developed an oxygen-enriched circulating fluidized bed gasification technology and built three 60,000 Nm3/h pulverized coal gasifiers for Xinjiang Yihua. By optimizing oxidant flow, furnace fluidization velocity, high-throughput recycle loops, and waste heat recovery systems, the design minimizes coking and reduces heat loss.
Since commencing operation in September 2020, the unit has operated smoothly with outstanding performance. Previously, Xinjiang Yihua’s shift gas section required shutdowns every three months for maintenance and relied on gas holders to stabilize pressure and adjust gas composition. Now, with stable syngas production, the gas holders have become redundant, greatly improving operational safety and reliability while ensuring high product quality downstream.
Notably, following project startup, prices for urea and melamine have surged, generating strong economic benefits for the owner. Zhang Zhonghua, Party Secretary of Xinjiang Yihua, stated that breakthroughs in circulating fluidized bed gasification have injected new vitality into the company’s green development. Over the next five to ten years, Xinjiang Yihua plans to develop a 1-million-ton-per-year melamine project to enable low-emission coal conversion, actively supporting China’s “carbon peak and carbon neutrality” goals. The project is now part of the key plans and major projects list in the Xinjiang Zhundong Economic and Technological Development Zone and is progressing steadily.
The long-term stable operation of Xinjiang Yihua’s gasification unit marks a major success in the industrial application of CFB gasification technology to high-alkali coal. It opens a new path for the clean and efficient utilization of high-alkali coal and sets a leading example in promoting high-quality regional economic development.
