The fifth section of the PGA project site leveling project has been started since November 2021, which has lasted 19 months. As the construction party, Beijing Yanhua Tianjing has completed a total of about 250,000 m³ earthwork excavation, 1.422 million m³ earthwork blasting (122 times in total), 1.89 million m³ earthwork backfilling, 726,000 square meters of dynamic consolidation treatment area, 134,000 square meters of impermeable barrier layer, and 1,600 meters of flood drainage trench construction, with a total of 338,000 safe labor hours.
Project construction includes coal gasification unit, gas cryogenic separation unit, coupling and hydrogenation unit, polyglycolic acid unit, supporting the construction of cogeneration unit and air separation unit. The raw coal is prepared by pulverized coal, gasification, transformation, purification, and cryogenic separation to obtain purification gas CO and H2, which provides raw materials for downstream coupling and hydrogenation units, and acidic gas produced by gasification units to produce sulfur. Methyl nitrite produced by methanol, nitric acid and sodium nitrite is coupled with CO to get dimethyl oxalate and by-product dimethyl carbonate (for sale). Dimethyl oxalate is partially hydrogenated to produce methyl glycolate, methanol and crude ethylene glycol (for sale), and methanol is separated for reuse. Methyl glycolate enters the polyglycolate unit for polymerization and depolymerization to produce ethyl ester. High molecular weight polyglycolic acid (main product) was produced by ring-opening polymerization of ethyl ester.