The Sanyou Chlor-Alkali project has successfully “integrated” soda ash production
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According to Sinochem New Network, on June 8, the first phase of the technological renovation project at Sanyou Group—involving a 400,000-ton/year polyvinyl chloride (PVC) plant and a 500,000-ton/year caustic soda plant—was successfully commissioned and put into production. Thus, the country’s first circular economy industrial chain encompassing soda ash, chlor-alkali, chemical fibers, and silicon industries has taken shape within this company. The successful completion and commissioning of this project have met the needs of Sanyou Group for mutual supply of products among its soda ash, chemical fiber, and silicon industries’ production lines, as well as for the comprehensive utilization of waste. According to reports, the total investment in this project is 497 million yuan. Based on partial capacity expansion modifications to the existing production system, it will enable the plant to produce 400,000 tons of PVC and 500,000 tons of caustic soda per year. In line with the strategy of technological leadership, this project utilizes a number of internationally and domestically advanced new technologies and equipment, including a high-current-density naturally circulating bipolar zero-gap ion-exchange membrane electrolyzer, a new type of steam synthesis furnace, energy-saving fluidized bed drying technology, and a large 106-cubic-meter polymerization reactor. These innovations have effectively reduced production costs; it is estimated that the project will generate annual benefits worth 36 million yuan. For every ton of polyvinyl chloride produced in a chlor-alkali plant, 1.59 tons of calcium carbide slag is generated. If this slag is simply stockpiled, it not only occupies a large amount of land but also causes pollution to the surrounding environment. Sanyou utilizes all the wet calcium carbide slag generated during the PVC production process to replace lime milk in both the ammonia stripping system for soda ash and the chemical fiber wastewater treatment facility, generating economic benefits of over 10 million yuan annually. It not only reduces the costs of lime production and calcium carbide slag treatment, but also prevents environmental pollution caused by the storage of calcium carbide slag, thus enabling the recycling of waste residues and effluents. The dilute brine generated by this caustic soda plant is sent to the company’s internal soda ash plant as raw material, which helps save a significant amount of raw salt and reduces both construction investment and raw material costs. In addition, the produced caustic soda also met the raw material requirements of chemical fiber and silica fume production facilities. The produced chlorine and hydrogen chloride can be integrated with the company’s existing silicone production facilities, thereby achieving a complete balance between chlorine and hydrogen chloride and preventing potential environmental safety hazards caused by storage overflow. Currently, the project has been designated by Hebei Province as a key circular economy construction project. (Gede Chemical Network)
In recent years, Sanyou has been expanding rapidly. Reportedly, their calcination workshop has seven or eight middle-level managers, who are there to cultivate technical personnel.
It seems like you guys keep in touch quite often; you even manage to pick up on such situations. :D
Originally, their calcination workshop consisted of two separate workshops: one for light ash and the other for heavy ash. Each workshop had four intermediate levels. Last year or this year, they were merged into one workshop; thus, this single workshop now has seven or eight intermediate levels. This isn’t the case in the other workshops.
Reportedly, two middle-level managers were also reassigned; otherwise, there might have been as many as ten.
This post was last edited by mkp369 on August 31, 2012, at 13:41. Calcium carbide slag is used in the ammonia stripping process; the integration of chlor-alkali and soda ash industries enables circular and sustainable development, thus facilitating the comprehensive utilization of resources. However, the ammonia stripping process inevitably generates acetylene gas. What measures should be taken for its recovery or to ensure the safe operation of the system?
Indeed. Carbide residue inevitably contains unreacted calcium carbide; during the ammonia stripping process, this reacts with water to produce acetylene gas. How can we address these safety concerns?
Is it possible to pass the chlor-alkali slurry through a desulfurization tower before ash formation, so as to wash out sulfur while separating hydrogen sulfide and acetylene for heating purposes?
Theoretically, it should be possible, but how many more devices would that require? Isn’t the cost going to increase? I doubt anyone would do this nowadays.