In recent years, the National Development and Reform Commission (NDRC) has released the "National Key Energy Conservation Technology Promotion Catalogue (First Batch)" which highlights 50 key energy-saving technologies. Among them, the new gas-based alkali production technology has been recognized as a powerful tool for achieving energy efficiency and emission reduction in the soda industry. This innovative method was developed under the leadership of Academician Zhou Guangyao from the Chinese Academy of Engineering. Since its implementation in companies, it has demonstrated remarkable energy-saving and emission-cutting performance.
According to the China Soda Industry Association, this technology can significantly reduce energy consumption per ton of alkali, lowering it from 10,000 to 15,000 MJ to 8,000 MJ, representing a 30% decrease. Additionally, it achieves nearly 99% utilization of raw salt and 96% utilization of ammonia, making it highly efficient and sustainable.
One of the main advantages of this technology is its streamlined process and minimal equipment requirements. It integrates the decarbonization of the ammonia system with the alkali production process into a single unit, eliminating the need for separate carbon dioxide removal systems. This not only reduces capital investment but also improves operational efficiency. The conversion gas is directly introduced into the base tower, where the decarburization task is completed during the alkali production process.
The equipment is also more compact and efficient, replacing the need for two separate units for alkali production and purification. With an extended washing cycle, wastewater discharge is minimized, leading to lower resource consumption. Furthermore, the technology lowers electricity usage by 100–120 kWh per ton of synthetic ammonia and 60 kWh per ton of alkali, while saving about 70–110 kg of gas per ton of alkali. It also increases production capacity in the calcining section and saves 15–25 kg of water per ton of alkali.
The system operates in a closed-loop, ensuring no wastewater is discharged. Computerized control further enhances precision and efficiency. Due to fewer processes and equipment, the workload for civil works, electrical installations, and other infrastructure is reduced. On the same scale of facilities, this technology can cut fixed asset investments by 20–25%. A rough cost analysis shows that each ton of alkali (including 1 ton of ammonium chloride) can reduce costs by 42–48 yuan.
The application of this technology not only brings significant energy savings but also extends the operating cycle of the alkali production towers, improves the quality of heavy alkali crystals, and reduces mother liquor volume. As a result, it helps achieve zero wastewater discharge in associated alkali production. This is crucial for advancing clean production and circular economy models in the soda industry, offering broad potential for future development.
During the “Eleventh Five-Year Plan†period, the China Soda Industry Association will actively promote this technology across the sector. Currently, its adoption rate is around 15%, with a target of reaching 50% by the end of the plan. This could lead to energy savings of up to 200 million kJ.
To date, this domestically developed, internationally advanced alkali production technology has been implemented in over a dozen companies across China, delivering substantial energy savings, emission reductions, and economic benefits. For example, Shijiazhuang Shuanglian Chemical Co., Ltd. invested 150 million yuan to implement a 300,000-ton project using the new technology, while Shanxi Fengxi Group Aoshan Alkali Industry Co., Ltd. invested 150 million yuan in a 10,000-ton project. Both achieved clean and efficient operations, with annual profit and tax increases of 60 million yuan and a new profit of 40 million yuan. Their return on investment was achieved within just 3.5 years.
The China Soda Industry Association encourages joint-alkali enterprises to adopt this technology for energy-saving upgrades, and ammonia-alkali producers are advised to use it for relocation or restructuring projects.
Suzhou Johnson Automation Technology Co., Ltd. , https://www.cn-johnson.com