On April 11, 2019, the EPC project of exhaust gas deep governance of 600kt/a DAP plant in Phase II project of Yunan Tian’an Chemical Co., Ltd. undertaken by Guizhou East China Engineering Co., Ltd. commenced successfully. Yunnan Tian’an Chemical Co., Ltd. is the largest synthetic ammonia producing enterprise in Yunnan Province. This project is mainly the technical transformation of exhaust gas purification system for DAP plant to achieve deep governance of exhaust gas, in order to reduce the air pollution of synthetic ammonia during the production process.