Yunnan Phosphorous Group Relies on Circular Economy to Survive the Crisis      

Yunnan Phosphorus Group Co., Ltd. is a private enterprise engaged in the production and sales of phosphorus chemicals, chlor-alkali chemicals, coal chemicals, salt chemicals and other chemical products. Faced with the global financial crisis, this company extends its industrial chain and significantly reduces its production costs by means of technological innovations, making its products gain a strong competitiveness in the market. In 2008, it achieved a product sales volume of RMB5.29 billion, twice that of 2007.

To extend the industrial chain    

After several tries, Yunnan Phosphorus Group finally designed an industrial chain to manufacture products from upstream to downstream. It makes use of self-produced calcium carbide, chlorine and hydrogen from the production process of caustic soda to produce polyvinyl chloride (PVC) resin. It also recovers alkaline wastewater through pressurizing and filtering the calcium carbide sludge concentrates, for the re-use in hydrolysis process of calcium carbide and the removal of sulfur dioxide flue gas from the thermal power plant. Calcium carbide sludge and lime powder from the calcium carbide plant and phosphate slag from the yellow phosphorus plant, are calcined together and decomposed into cement clinker, which is then formulated with fly ash from the thermal power plant to produce cement. Steam generated in the thermal power plant is used for the production of caustic soda and PVC resin, and the electricity power is used for the manufacturing of caustic soda and calcium carbide.
   Through a series of technological innovations, Yunnan Phosphorus Group has realized zero emission throughout its production process and achieved the highly efficient utilization of resources.

Energy conservation in production    

Yunnan Phosphorus Group has constantly reduced the consumption of energy, raw materials and water and strived to improve the utilization efficiency of resources.
   For example, in the vinyl chloride monomer workshop of its 130 000 t/a PVC unit, Yunnan Phosphorus Group adopts the absorption-desorption process to gather the excess hydrogen chloride in the polyvinyl chloride polymerization section for reuse. In its distillation unit, high-boiling substance wastes are turned into treasures through refining in the company's three-column distillation system. The company also uses the pressure swing adsorption process to recover vinyl chloride, acetylene and hydrogen from low-boiling distillation tail gas, returns the recovered hydrogen into the production process of hydrogen chloride and converts all the excess chlorine into hydrogen chloride for the production of PVC. In its ion-exchange membrane caustic soda unit, the company uses hot water from the hydrogen chloride synthesis furnace in the lithium bromide refrigeration unit to produce 70 centigrade degree cooling water. This has substantially saved the steam and power consumption. In another example, Yunnan Phosphorus uses the tail gas from the yellow phosphorus plant to produce solid caustic soda. The tail gas has a high content of carbon dioxide, thus through reacting with caustic soda solution it can make sodium carbonate that can be used in the primary brine system.
   In addition, Yunnan Phosphorus Group has also built a series of matching projects for energy conservation and environmental protection. For example, through the granulation of coke nut and the recycling of yellow phosphorus tail gas, the company can save about 20 000 tons of standard coal a year, equivalent to saving RMB14 million a year.

To recycle waste resources       

While vigorously promoting cleaner production and reducing pollutant emissions from the beginning, Yunnan Phosphorus Group endeavors to recycle and utilize wastes. The key processes of its PVC resin, caustic soda and power plants all adopt the stable and reliable distributed control system (DCS) technology to ensure energy conservation, pollutant reduction and clean production. In the acetylene workshop section of its PVC plant, the company uses the advanced bag dust removal technology to recover calcium carbide powder for reuse. Mother liquor from the PVC polymerization process is filtered with membranes for treatment, and then returned to the PVC production system. The company has also built a 800 000 t/a cement plant to make full use of calcium carbide slag from the PVC plant, fly ash from the thermal power plant and phosphorus residue from the yellow phosphorus plant. Through these measures, the company can basically recycle all of its industrial wastes.
    All of the recycling tactics can add economic benefit of about RMB50 million a year for Yunnan Phosphorus Group.