Major Progress in 150,000-Tonne-per-Year Cotton Stalk High-Yield Clean Pulping and Papermaking Project

On the eve of National Day, a major breakthrough was made in the 150,000-tonne-per-year high-yield clean cotton stalk pulping and papermaking project built in Shihezi City, Xinjiang Uygur Autonomous Region, with key technology provided by the Institute of Chemical Industry of Forest Products under the Chinese Academy of Forestry: the plant buildings have been fully completed and all key equipment has been installed in place.

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

As China's main producing area for high-quality cotton, Xinjiang produces 15 million tonnes of cotton stalks each year; at present the main ways of handling cotton stalks are simply crushing them and returning them to the field or burning them directly. Returning cotton stalks to the field degrades the soil of cotton fields, while direct burning produces large amounts of thick smoke, which not only pollutes the environment but also easily causes fires and traffic accidents, threatening the lives and property of local people, while also wasting large amounts of fiber resources. How to effectively use the huge quantity of cotton stalk waste has become a major problem local governments urgently need to solve.

In recent years, with the growth of China's paper and paperboard consumption and the rapid increase in production capacity, the self-sufficiency rate of domestic papermaking fiber raw materials has been hard to raise, and the contradiction between supply and demand 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 the import of waste plastics from domestic sources, unsorted waste paper, textile waste, vanadium slag and other types. 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 papermaking fiber raw materials has become the main bottleneck constraining the sustainable development of China's paper industry.

In 10 regimental farms including the 122nd Regiment located in Shihezi City, as well as 277 administrative villages in 28 townships across 5 counties (cities)—Shihezi City, Shawan County, Hutubi County, Changji City and Manas County—the total annual volume of cotton stalks collected within a 50-kilometre radius can reach more than one million tonnes. How to turn this into a resource and treasure 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, systematically analysing the fiber components of Xinjiang cotton stalk xylem, phloem and residual cotton, and analysing non-fiber components such as the cotton stalk epidermis and pith core, concluding that Xinjiang cotton stalks are a high-quality papermaking raw material. To overcome the difficulties as soon as possible, within one year every member of the team worked "day and night" and "five plus two," finally completing small-scale research on the processes of cotton stalk cutting, washing, steaming, chemical impregnation, refining, biological enzyme treatment, latency removal, screening, coarse reject treatment and purification and concentration, and on this basis completing pilot tests and developing 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 the 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 centre on the Silk Road Economic Belt, Xinjiang has broad demand for corrugated paper packaging products. In addition, the non-fiber components in cotton stalks, and waste such as solids produced in pulping and wastewater treatment, are rich in organic matter, nitrogen, phosphorus, potassium and trace elements, and are an important source of organic fertilizer for agricultural production. As an important major agricultural province and main producing area of fruits and vegetables in China, Xinjiang has huge market demand for bio-organic fertilizer.

Based on the characteristics of the cotton stalk raw material, the project's designed product is high-strength corrugated base paper, which sells well on the market, positioned at the premium grade A level. The project will effectively treat and turn into resources the waste residue, wastewater and waste gas generated in the production process, achieving comprehensive clean production. The works will 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