At the end of September 2021, the Phase II indirect cooling upgrade project for the fixed-bed gasification unit at Shanxi Jinxiang Coal Chemical Co., Ltd., constructed under EPC contract by CAS Hefei Coal Gasification Technology Co., Ltd. (“ZHGAS”), achieved mechanical completion and began system commissioning and pilot testing as scheduled.

Shanxi Jinxiang Coal Chemical Co., Ltd. is a joint venture established by Jinneng Holding Equipment Manufacturing Group Co., Ltd. and Yangcheng Huangcheng Xiangfu (Group) Industrial Co., Ltd., with an annual output of 180,000 tons of synthetic ammonia and 300,000 tons of urea. The gasification unit uses intermittent fixed-bed gasification technology, with a conventional gas cooling and purification system based on direct water washing for dust removal and cooling. This caused environmental problems such as tar and phenol wastewater generation.

The upgrade project eliminated the original direct water washing dust removal and cooling process by installing two sets of dry baghouse dust collectors combined with indirect cooling systems. This tightly integrated technology captures coal gas dust while resolving the high pollution issues caused by circulating water in direct washing. Additionally, condensate from the gas cooling system is treated via the ammonia stripping system for reuse as dilute ammonia water.

Since signing the contract in late May 2021, the four-month construction period faced multiple challenges, including recurring COVID-19 outbreaks causing labor shortages, delayed delivery of key equipment due to severe flooding affecting suppliers in Henan, and several consecutive days of heavy rain reducing effective work hours. The project team responded proactively, coordinating closely with equipment suppliers and subcontractors, optimizing the schedule, assigning clear responsibilities, and ensuring steady progress. Ultimately, mechanical completion was achieved on schedule by late September, followed by successful pilot testing.

Currently, the upgraded system operates stably, with post-treatment coal gas temperature and dust content both surpassing design targets. The overall plant environment has significantly improved, meeting strict environmental compliance standards.

Before the upgrade, the gasification unit’s circulating water pool discharged waste gas unsealed and produced sediment sludge that required filtration before co-firing. Post-upgrade, waste gas is fully enclosed and sent to a waste incinerator for compliant disposal, while separated dust in dry ash form is directly co-fired with boiler fuel, eliminating wastewater from filtration and reducing production costs.

Since its establishment, ZHGAS has remained market-oriented and responsive to industry needs, continually innovating to address practical production challenges. Through this indirect cooling upgrade, ZHGAS has extended the service life of existing equipment, revitalized fixed-bed intermittent gasification technology, and provided strong economic and social benefits to the owner.