Soda ash: Traditional industries show a new face

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This post was last edited by mkp369 on September 27, 2012, at 14:17. Soda ash: Traditional industries show a new face. Author: Yu Hong. Source: China Chemical Industry News. Updated on September 27, 2012. — Exhibition of achievements in the petroleum and chemical industries · Part II: Industrial sector. According to ChemNet China, over the past decade, China’s soda ash industry has seen continuous rapid development. This is manifested in a significant increase in production capacity and output, substantial progress in energy conservation and emission reduction, marked improvements in technological equipment levels, and further enhancement of enterprise management standards. 　　Statistics from the China Soda Ash Industry Association show that over the past decade, the annual domestic production of soda ash has risen from 10.11 million tons in 2002 to 22.36 million tons in 2011. Meanwhile, the product structure has been further adjusted, and the current production capacity for heavy soda ash and dry ammonium chloride continues to increase. Gone is the previous situation where most soda ash products were light soda ash and wet ammonium chloride. Currently, heavy soda ash accounts for 42% of the entire industry’s output, while dry ammonium chloride makes up over 50%. The proportion of heavy soda ash and dry ammonium chloride among all soda ash products is becoming increasingly balanced. 　　To reduce production costs, the raw material routes for soda ash are constantly being improved. Currently, the production of soda ash has shifted from requiring only anthracite lumps to also allowing the use of coal briquettes made from pulverized coal. This has significantly reduced raw material costs, while the range of applicable coal types continues to expand. Additionally, enterprises can now use smokeless lump coal to produce lime instead of coke, thereby also reducing the production cost of lime. 　　According to Wang Xiling, president of the China Soda Ash Industry Association, the soda ash industry is a traditional strength sector in China, and the country has now become the world’s largest producer and consumer of soda ash. Over the past decade, through various efforts, the soda ash industry has made significant progress in energy conservation and emissions reduction, giving this traditional industry a new look. 　　On one hand, energy consumption for raw materials has been significantly reduced. According to statistics from the China Soda Ash Industry Association, a decade ago, the average salt consumption at major domestic ammonia-soda process plants was 1,600 kg per ton of soda ash; currently, this figure has dropped to 1,500 kg per ton. Thus, salt consumption has decreased significantly ； The ammonia consumption in ammonia-soda plants has decreased from 10 kg per ton of soda in the past decade to the current 3–4 kg per ton of soda. 　　The salt consumption in domestic soda ash plants has decreased from 1,200 kg per ton of soda ash a decade ago to the current level of 1,100–1,150 kg per ton. Meanwhile, ammonia consumption has also dropped significantly, from 400 kg per ton of soda ash to 340–350 kg per ton. It is understood that large high-pressure boilers, which were virtually non-existent ten years ago, have been widely used in soda ash plants in recent years, enabling multi-stage utilization of steam and effectively reducing energy consumption. 　　On the other hand, environmental protection efforts in the soda ash industry are also making continuous progress, with various tasks being carried out effectively. Among them, ammonia-soda enterprises such as Shandong Haihua Group, Guangzhou Southern Alkali Industry Co., Ltd., and Qingdao Soda Ash Co., Ltd. have successfully utilized ammonia-soda waste residues for the desulfurization of boiler flue gas. This not only recovers sulfur dioxide from the flue gas and reduces atmospheric pollution caused by gas emissions, but also enables the comprehensive utilization of the waste residues, thereby eliminating their adverse impact on the marine environment—achieving dual benefits in environmental management. 　　Tangshan Sanyou Group uses oxygen-enriched gas generation in its lime kilns, which has increased the production capacity of the kilns, raised the carbon dioxide concentration in the kiln gas, and reduced the consumption of coke/anthracite. In recent years, soda ash plants such as Jiangsu Huachang Chemical Co., Ltd. and Haohua Honghe Chemical Co., Ltd. have continuously strengthened their management efforts, resulting in a reduction in the volume of mother liquor. Additionally, wastewater generated in other processes is recycled back into the system, thereby ensuring that virtually no wastewater is discharged externally. 　　In recent years, in the process of retrofitting existing facilities, relocating production sites, and constructing new plants, soda ash enterprises have made extensive use of newly developed domestic processes, technologies, and equipment. As a result, the technological and equipment standards of large-scale soda ash plants have advanced significantly toward being more advanced, large-scale, efficient, and energy-saving, bringing them close to the world’s leading level. 　　The development of a combined production process for melamine and soda ash has been successful. In recent years, some soda ash producers have built melamine production plants in their vicinity. The off-gases generated during melamine production—primarily ammonia and carbon dioxide—are entirely utilized in the production of soda ash. This approach is environmentally friendly, cost-effective, and helps to reduce energy consumption. 　　In the soda ash industry, a new process involving the combined production of salt, alkali, and calcium has emerged. Last year, this process was first put into operation at Jiangsu Jingshen Salt Industry Co., Ltd., a company with salt mines. It involves pumping underground brine to produce calcium chloride and salt simultaneously; the salt is then used to manufacture soda ash, thus enabling the comprehensive utilization of the brine. 　　Haikua Company and Tangshan Sanyou Company have begun using calcium carbide slag to purify brine as a substitute for lime. This not only helps save lime but also eliminates the need to discharge calcium carbide slag externally. Promote dry lime addition and vacuum distillation in ammonia-soda plants. The promotion of belt-type vacuum alkali filters and similar equipment across the entire industry has enhanced the effectiveness of energy conservation and emission reduction. 　　In particular, the industry is currently developing and constructing thermal soda ash co-production facilities. At present, apart from Jiangsu Hongze Yinzhu Company, which has already built a pilot plant with an annual capacity of 150,000 tons, Haohua Honghe Company will also construct a thermal soda ash co-production plant with an annual capacity of 600,000 tons; construction is set to begin this year. Its significance lies in the fact that the ammonia-soda process used thus far has been a freezing-based method, which involves cooling dried salt to produce ammonium chloride ； The thermal process, on the other hand, eliminates the energy-intensive steps of evaporating brine to produce salt and then freezing it to produce ammonium chloride; instead, brine is used directly in the production of ammonium chloride. 　　According to Wang Xiling, apart from the research, development, and application of the aforementioned new processes and equipment, the industry has also made new breakthroughs in areas such as production methods for heavy soda ash and improvements to carbonation towers. Ten years ago, the conventional solid-phase hydration method was used for producing heavy soda ash. In recent years, however, methods such as extrusion, wet mixing, modified wet mixing, and liquid-phase hydration have all seen development, enabling them to meet the diverse needs of users. 　　In terms of carbonation towers, the industry has broken the monopoly held by Solvay’s towers as the key equipment in soda ash production. Several new types of carbonation towers—such as sieve tray towers, externally cooled towers, and uncooled towers—have been independently developed. These now coexist with Solvay’s towers, contributing to further reductions in energy consumption.