【Ten Years of Rapid Development in Chemical Equipment】The world’s first 10,000-ton-scale demonstration project for coal-based biodegradable materials was put into industrial production between 1978 and 2022
Thread Content
Witnessing the ten-year rapid development of chemical processing equipment, I praise the prosperity and strength of modern China. Wishing everyone a happy New Year, and may their families enjoy peace and good health. By contributing our ideas, we can create a more lively discussion environment; HaiChuan becomes even better with your participation. Everyone is welcome to join in the forum discussions more actively. ----------------------------------------------------- On September 19, 2022, the 50,000-ton/year polyglycolic acid (PGA) biodegradable materials production project operated by **Energy Group Yulin Chemical Co., Ltd. completed all its production processes and was officially put into operation, marking the industrialization of the world’s first 10,000-ton-scale coal-based biodegradable materials production project. The coal-based biodegradable materials produced by this project utilize **technology owned by the Energy Group, with all key equipment being domestically manufactured. Compared with the production of traditional polyolefin plastics, coal-based polylactic acid biodegradable materials can reduce coal consumption per ton of product by about 50%, cut carbon dioxide emissions by around 65%, and increase industrial added value by 2 to 3 times; meanwhile, their production costs remain similar, giving them strong market competitiveness and environmental benefits. It is reported that the biodegradable materials produced by this project can largely replace single-use plastic products, and they can degrade completely without causing any harm in environments such as soil and seawater. The products of this project can be used to manufacture disposable tableware, plastic bags and other daily necessities; they also have a wide range of applications in high-end fields such as medical surgical sutures, agricultural plastic films, and the extraction of unconventional oil and gas underground. This provides new approaches for China to address white pollution and meet the needs of its citizens.
On April 2, 2022, the installation of the first reactor in **Energy Group Yulin Chemical Co., Ltd.’s 50,000 t/a polyglycolic acid biodegradable materials (PGA) demonstration project was completed, laying the foundation for the construction and operation of the prepolymerization unit.
The second vacuum reactor lifted this time is an important reaction equipment in the prepolymerization unit of this project. It was manufactured by Lanzhou Lanshi Heavy Equipment Co., Ltd., with specifications of Ф2 800×3 000 mm and a weight of 46 tons. A 500-ton crane was used for the lifting operation, while a 25-ton crane was employed to assist in adjusting its position.
On May 16, the truck carrying MG synthetic catalysts, dispatched from Shanghai Pujing Chemical New Materials Co., Ltd., arrived successfully at the Qingshui Industrial Park in Yulin. The MG synthesis system of the PGA demonstration plant relies on the hydrogenation unit of the 400,000 tons per year ethylene glycol plant located within the facility; by using the existing ethylene glycol hydrogenation reactors and replacing the catalysts, it enables flexible production of methyl glycolate (MG) as a co-product of ethylene glycol (MEG). It is reported that starting from May 22, the PGA unit at Shenhua Yulin Chemical will begin a process of installing MG catalysts that will last around 10 days. It is expected that qualified MG products will be produced in early June, thereby laying the foundation for the operation of the subsequent polymerization units.
**Shenhua Yulin Energy Chemical Co., Ltd., an energy group, is carrying out a demonstration project for the production of 50,000 tons per year of polyglycolic acid-based biodegradable materials (PGA). Location: North Area of Qingshui Industrial Park, Yushen Industrial Zone, Yulin City, Shaanxi Province. Total investment for the project: 94,024.98 yuan. Commencement date: March 2021. The project includes units for refining, pre-polymerization, pyrolysis and cyclization, purification, solvent recovery, final polymerization and molding, as well as packaging facilities. It also includes supporting systems such as a refrigeration station, heat transfer oil station, substation, cabinet rooms, plant-wide systems, and a recirculating water station (to be renovated). The project is located in the Qingshui Industrial Park in Dabaochang Town, Shenmu City, Yulin City, Shaanxi Province, covering an area of 9.8 hectares. It utilizes technology provided by Shanghai Pujing Chemical Industry, and is a **-level demonstration project as well as an extension project for the coal-to-olefins industry chain of ** Energy Group in Yulin. The project passed the technical review in November 2020, with production scheduled to begin in 2022.
In response to the special requirements related to high material viscosity, poor fluidity, and low-temperature high-vacuum drying, the drying specialist team at Tianhua Institute established an emergency task force. Over the course of a year, they succeeded in developing the processes and equipment technologies for the lactide drying unit in this project, and managed to design and manufacture a low-temperature continuous drying system capable of operating at an absolute pressure of 500 Pa.A. This device can adapt to materials of different properties and states, and is particularly suitable for drying flammable and explosive materials, those prone to high-temperature oxidation and thixotropic materials, as well as pasty, viscous, and creamy substances. During the drying process, this technique enables maximum mixing of the material through the continuous back-and-forth rotation of the rake teeth, thereby effectively improving the heat transfer conditions of the material, preventing it from overheating, and making it easier for the moisture in the material to evaporate. In terms of design, this device uses auxiliary equipment such as a shell-and-tube condenser with a simple structure, which enhances the condensation and recovery of solvent vapor; the solvent recovery rate can reach over 95%. A reasonable structural design, an integrated processing technique for the large end plates, as well as the appropriate selection of shaft end sealing structures and sealing materials, ensure both the sealing performance of static seals and that of dynamic seals. Its unique medium fluid channel ensures that the medium fluid does not experience short circuits or dead zones, thereby enhancing heat transfer between the medium fluid and the material and significantly improving thermal efficiency. Various speed control technologies are available; according to user requirements, variable frequency, electromagnetic, or mechanical stepless speed control can be used, thereby facilitating the adjustment of the rotation speed of the hollow shaft.
The rubber and plastics specialty team at Tianhua Institute was responsible for the design and manufacturing of the key equipment, namely the lactide granulation unit, for this project. The lactide granulation unit of this project is required to evenly distribute PGA resin with a production rate of 2300 kg/h through DN100 pipes and extrude it uniformly into 70 flat die holes with a width of 1100 mm, and to cool the material strips on a air-cooled steel belt from 230°C to below 70°C in order to meet the granulation requirements. In light of the complexity of the materials used in the lactide cooling granulation unit, Tianhua Institute’s plastics and rubber engineering team assembled a team of experts. Drawing on over 40 years of experience in extrusion granulation and utilizing advanced computer simulation techniques, they designed the key components of the equipment. Through numerous experiments, refinements, and improvements, they successfully developed a granulation unit featuring a unique hanger-style flow channel, which ensures both uniform material discharge and consistent quality of the final particles. At the same time, through precise calculations and simulation analyses, a set of cooling devices for the extruded strips along with the operating procedures were determined for the owner, and appropriate operating temperature parameters were set; these ensure that the material is adequately cooled while preventing moisture degradation of the material due to dew formation on the granulated steel strip.