Shihezi 150,000 t/y Cotton-Stalk Clean Pulping Project Hits Milestone: Buildings Complete, Key Equipment Installed

Just before National Day, the 150,000-tonne-per-year cotton stalk high-yield clean pulping and papermaking project in Shihezi City, Xinjiang Uygur Autonomous Region, reported important progress: the plant buildings have been fully completed and all key equipment has been installed in place. Key technology for the project is provided by the Institute of Chemical Industry of Forest Products under the Chinese Academy of Forestry.

Phase I of the project involves an investment of more than 264 million yuan and a total land area of 434 mu, including 180 mu for newly built works. Once Phase I is completed, it will use abundant local cotton stalk fiber as raw material to supply the market with 150,000 tonnes per year of high-grade corrugated base paper, a product in tight supply.

Xinjiang is China's main production area for high-quality cotton and produces 15 million tonnes of cotton stalks annually. At present, most cotton stalks are simply crushed and returned to fields or burned directly. Returning them to fields degrades cotton-field soil quality, while direct burning generates heavy smoke that pollutes the environment and can easily cause fires and traffic accidents, threatening the lives and property of local people and wasting large amounts of fiber resources. How to effectively use the huge volume of cotton stalk waste has become a difficult problem that local governments urgently need to solve.

In recent years, China's paper and paperboard consumption has grown and production capacity has expanded rapidly, but the self-sufficiency rate of domestic papermaking fiber raw materials has been difficult to improve, and the supply-demand contradiction has intensified. In 2017, the General Office of the State Council issued the Implementation Plan for Prohibiting the Entry of Foreign Garbage and Advancing the Reform of the Solid Waste Import Management System, banning imports of waste plastics from domestic sources, unsorted waste paper, textile waste, vanadium slag and other categories. By the end of 2020, China had achieved zero imports of solid waste, further worsening the shortage of domestic papermaking fiber raw materials. The severe shortage of fiber raw materials has become a major bottleneck constraining the sustainable development of China's paper industry.

Across 10 regimental farms such as the 122nd Regiment in Shihezi City, together with 178 agricultural companies, and 277 administrative villages in 28 townships across five counties or cities—Shihezi City, Shawan County, Hutubi County, Changji City and Manas County—the total volume of cotton stalks collected each year within a 50-kilometre radius can reach more than one million tonnes. Turning them into resources and value is an urgent issue for local economic development.

In 2018, with strong support from the Shihezi City government, Shihezi Guoliyuan Environmental Protection Pulping Co., Ltd. signed an agreement with the Chinese Academy of Forestry to cooperate in building a one-million-tonne cotton stalk comprehensive utilization circular economy industrial park. Fang Guigan, deputy director of the Institute of Chemical Industry of Forest Products under the Chinese Academy of Forestry, led a team in scientific research on Xinjiang cotton stalk fibers. They systematically analyzed fiber components such as xylem, phloem and residual cotton, as well as non-fiber components such as epidermis and pith core, and determined that Xinjiang cotton stalks are a high-quality papermaking raw material. To overcome the technical challenges as soon as possible, every team member worked in day-plus-night and five-plus-two mode throughout one year, finally completing small-scale research on cotton stalk cutting, washing, steaming, chemical impregnation, refining, biological enzyme treatment, latency removal, screening, coarse reject treatment, and purification and concentration. On this basis, they completed pilot tests and developed ahead of schedule a new biological high-yield pulping technology for Xinjiang cotton stalks.

Cotton stalk raw material contains not only fiber components such as xylem, phloem and residual cotton, but also non-fiber components such as epidermis and pith core. The fiber component is an excellent pulp raw material for packaging paper products. As an important transport hub, trade logistics and cultural, educational and scientific center on the Silk Road Economic Belt, Xinjiang has broad demand for corrugated paper-based packaging products. In addition, non-fiber components in cotton stalks, as well as waste such as solids generated during pulping and wastewater treatment, are rich in organic matter, nitrogen, phosphorus, potassium and trace elements, and are an important organic fertilizer source for agricultural production. As an important major agricultural province and main fruit and vegetable production area in China, Xinjiang has huge market demand for bio-organic fertilizer.

Based on the characteristics of the cotton stalk raw material, the project is designed to produce high-strength corrugated base paper, a market bestseller, with the product grade positioned at premium Grade A. The project will effectively treat and resource-utilize waste residue, wastewater and waste gas generated during production to achieve comprehensive clean production. The project is scheduled to be completed and put into operation in the first half of 2022.

——This article is reprinted from China Packaging Network (pack.cn). Original link: http://news.pack.cn/show-378443.html