Recently, China National Energy Group’s Yulin Chemical demonstration project for 50,000-t/a polyglycolic acid (PGA) degradable materials, in which Tianhua Institute participated, was put into production. In the project, Tianhua Institute has offered advanced drying & pelletizing technologies and other key processes as well as the design and manufacturing of core equipment.
The project’s completion marked the industrial production of the world’s first 10,000-ton coal-based degradable materials demonstration project. China has made a breakthrough in the PGA biodegradable plastic field. It has been of demonstration significance in boosting the transition of China’s coal-based chemical industry towards the high-end, diversified and low-carbon development.
Degradable plastics is being brought to market in the context of demanding environmental requirements. PGA is an aliphatic polyester polymer material featuring the least amount of unit carbon, a completely decomposed ester structure and a fast degradation rate. It has good gas barrier properties, excellent biocompatibility, high mechanical strength, and high temperature resistance. As such it can be completely harmless in soil, seawater and other environments. It is widely used in oil and natural gas extraction, medical sutures, fracture fixation materials, and tissue engineering scaffolds as well as medicine, agroforestry, food packaging and other fields. At present, the world’s production capacity accounts for only 1% of the demand, with a broad market prospect.
This project has difficulties such as new process, new materials, and complex physical properties. To ensure qualified products, Tianhua Institute’s drying team established a research team to meet the material requirements of high viscosity, poor fluidity and low-temperature high vacuum drying. It took one year to complete the ethylene polyester drying process and equipment technology and design and manufacture a low-temperature continuous drying unit that can meet the absolute pressure of 500Pa.A. Tianhua Institute’s rubber & plastics team organized personnel to develop uniform, stable and large-width molds to ensure the uniformity of finished particles through 40-plus years of extrusion & pelletizing experience and by using advanced computer-aided simulation to design the core parts of the equipment. Meanwhile, through accurate calculation, the owner was assisted in setting proper operating temperature parameters, which can ensure sufficient cooling of materials and avoid moisture degradation of materials after condensation of pelletized steel strips.
During the installation and commissioning, the engineering technicians of Tianhua Institute in the epidemic period overcame the problems such as tight construction period, cross-professionals, and great difficulty, held onto their position around the clock, and analyzed and solved the problems arising during the commissioning overnight. After continuous efforts, the production process of the glycolide drying unit was opened and the equipment and the complete set of processes were delivered smoothly. After learning that his mother's falling injury led to brain surgery, the rubber & plastic institute’s PLC commissioning engineer still insisted on completing the single-action and chain tests of all equipment before returning home, which was praised by the owner.