Among the 50 key energy-saving technologies published by the National Development and Reform Commission (NDRC) recently published in the “National Key Energy Conservation Technology Promotion Catalogue (First Batch)â€, the new conversion gas-based alkali technology was selected as a tool to overcome energy-saving and emission reduction in the soda industry. Zhou Guangyao, an academician of the Chinese Academy of Engineering, led the development of this advanced alkali-producing technology, which has significant energy-saving and emission-reduction effects after being used in the company. According to analysis by China Soda Industry Association, this technology can reduce the energy consumption per ton of alkali in China from 10,000 to 15,000 MJ to 8,000 MJ, and the unit energy consumption per ton of alkali can be reduced by 30%. Using this technology, raw material salt utilization can reach 99%, and raw material ammonia utilization can reach 96%.
To create a process route with Chinese characteristics China is the world's largest producer of soda ash and the largest number of production methods. The combined soda production process has become a mainstream method for the production of alkali in China because of its high utilization of raw materials, low energy consumption, minimal waste liquid waste discharge, and easy environmental protection. The new conversion gas to make alkali is a typical Chinese characteristic new process in the production of the soda process.
This new process was the result of the cooperation between the China National Chengda Chemical Engineering Company and Shijiazhuang Shuanglian Chemical Co., Ltd., the largest converting gas production plant in China, in the late 1990s, led by Zhou Guangyao, the national alkali expert and academician of the Chinese Academy of Engineering. Recognized by the former National Petroleum and Chemical Industry Bureau, this technology is the first of its kind at home and abroad, and it is at the leading international level in the field of synthetic alkalis. This new process has created a new road for the development of our country's synthetic alkali technology.
The new conversion gas-alkali technology adopts the theory of low-temperature circulating alkali production, improves the quality of heavy alkali crystals, reduces the equivalent weight of washing water, prolongs the operation cycle of the alkali production tower, and realizes zero discharge of the waste liquid in the joint alkali system. At the same time, the technology has changed the traditional three-tower system to produce single-alkali soda, changing internal heat exchange to external heat transfer, reducing resistance and saving energy.
The advantages of energy saving and consumption reduction are highlighted The new conversion gas and alkali production technology has several advantages in terms of energy saving and consumption reduction: First, the process is the shortest and the equipment is the least. The process combines the two processes of decarburization of ammonia system with alkali production of alkali to form a unit, eliminating the need for investment in the carbon dioxide removal process of the ammonia system, and enabling the decarbonization process to be completed part-time by the alkali production process, as long as the conversion gas is directly introduced into the process. The base tower completes the decarburization task. The second is that the equipment is full-featured and highly efficient, eliminating the need for ancillary equipment. In the past, it was necessary to use two equipments to complete the production of alkali and purification, and the new conversion gas to make alkali has improved the structure of the equipment so that one tower played the role of two towers. Moreover, due to the greatly extended washing cycle, wastewater discharge is also reduced and consumption is reduced.
At the same time, by using this technology, the electricity consumption of synthetic ammonia tons of alkali can be reduced by 100 to 120 kWh, the electricity consumption of Alkali alkali can be reduced by 60 kWh, and the gas saving can be about 70 to 110 kg/ton of alkali. The calcining section can increase the production capacity. % of water; the average estimated water saving is 15~25 kg/ton of alkali. The production system is a closed circuit system with no wastewater discharge.
In addition, the technology also implements computer operation control. At the same time, due to the reduction of processes and equipment, the workload of civil works, electricity meters, installations, etc. has been correspondingly reduced. On the same scale of facilities, the application of this technology can save investment in fixed assets by 20% to 25%. According to a rough calculation, every ton of alkali (including 1 ton of ammonium chloride) can reduce the cost of 42 to 48 yuan.
Promotion and application of industrial competitiveness to improve the competitiveness of the industry The application of the new conversion gas-alkali production technology to joint-alkali production enterprises not only has significant energy-saving effects for ton-alkali, but also can effectively prolong the operation cycle of the alkali production tower, improve the quality of the heavy alkali crystals, and achieve significant shrinkage of the mother liquor of the alkali system. In turn, we will achieve zero discharge of wastewater from the production of associated alkalis. This is of great significance to the realization of cleaner production and the adoption of a recycling economy in the soda industry, so the prospect for promotion is very broad.
During the “Eleventh Five-Year Plan†period, China Soda Industry Association will vigorously promote this technology to the entire industry. The technology's current penetration rate in the soda ash industry is around 15%. It is expected that it will reach 50% during the “Eleventh Five-Year Plan†period and energy savings of 200 million megajoules will be achieved.
So far, this domestic first and internationally leading new technology for alkali production has been promoted and applied in more than a dozen homes in China, and has achieved significant energy-saving and emission-reduction effects as well as economic and social benefits. Taking Shijiazhuang Shuanglian Chemical Co., Ltd. and Shanxi Fengxi Group Aoshan Alkali Industry Co., Ltd. as an example, the former invested 150 million yuan to implement 300,000 tons of new energy-saving conversion gas-based technology and the latter invested 150 million yuan. 10,000 tons of new conversion gas production alkali technology project. Both companies have achieved clean and efficient production with an annual increase of 60 million yuan in profits and taxes and a new profit of 40 million yuan. The investment recovery period is only 3.5 years.
China Soda Industry Association recommends that joint-alkali enterprises should use this technology to carry out energy-saving technological reforms, and enterprises using ammonia-alkali production can use this technology for relocation and resettlement.