Since 2013, to address the challenge of utilizing low-rank fine coals (long-flame coal & lignite), ACRE leveraged its proven JL-series Indirect Heating vertical retorts for lump coal and invested RMB 40 million to successfully develop the "Indirect Heating Low-Rank Fine Coal Retort (JNWFG Retort)" after over 5 years of R&D. This pilot unit conducted continuous carbonization trials for over 3 years on low-rank coal from Northern Shaanxi and Naomaohu, thoroughly addressing the key challenges in other low-rank fine coal carbonization processes, such as high dust content in high-temperature raw gas, high ash content in tar, and poor gas quality. 

This technology enhances retort stability and sealing performance by adding gas channels in the middle and sides of the coking chamber to accelerate gas extraction speed while reducing internal gas pressure. It employs coke dry quenching process, using indirect water cooling to cool high-temperature upgraded coal. The generated hot water transferred to downstream units such as refrigeration stations and desulfurization units, achieving efficient comprehensive heat utilization. The entire process features significant energy efficiency, environment-friendliness, and water saving, aligning with green economy development. 

This technology holds more than 20 invention patents and 40 utility model patents, with achievements recognized as domestically leading. The national standard GB/T 44029-2024 "Technical specification for continuous carbonization of low-rank coal breeze by indirect heating process" developed by ACRE based on this technology is currently valid.