Successful commissioning of the three units supporting Tianye’s ethylene glycol production

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Successful Commissioning of Three Units Supporting Tianye’s Ethylene Glycol Production Facility Author/Source: Date: 2018-08-23 Clicks: 14 Recently, news came from Tianzhi Chenye of Tianye Group stating that the turbine, booster pump, and air compressor – the three units that make up the air separation unit part of the company’s 100,000 tons per year ethylene glycol expansion project – were successfully commissioned in a single attempt, meeting all design requirements with all operational parameters within normal ranges. As the key supporting equipment for this project, the successful first-time commissioning of the three units provided a solid foundation for the commissioning of the main equipment. At the same time, the successful first-time commissioning of the three units of the air separation unit supporting the ethylene glycol project is of great significance to the industry. 　　This project involves the construction of a new air separation unit with a capacity of 40,000 Nm3/h. The three compressors in this unit compress atmospheric air, which is then sent to subsequent processing stages; they are the core equipment that supplies raw materials and power to the air separation system. This air separation unit was designed by Kaifeng Air Separation Co., Ltd., and it supplies the oxygen, nitrogen, instrument air, compressed air, liquid oxygen, and liquid nitrogen required for production. In October 2016, Kaifeng Air Separation Group signed a supply contract with Tianzhi Chenye. The plant utilizes a process that involves packing in the towers, compression within liquid pumps, and preliminary purification at the beginning of the process – that is, preliminary purification using molecular sieves at room temperature. An air pressurization turbine expander provides the cooling required by the plant; air is pressurized and expanded, followed by distillation in twin towers, with compression taking place within liquid pumps. The entire air separation plant is controlled using DCS technology. 　　According to Zhang Lei, the person in charge of air separation for this project, achieving success on the first attempt in the joint testing of the three units was no easy task. During the early stages of testing, the unit faced issues such as low external temperatures and fluctuations in main steam flow and pressure. To address these issues, workshop engineers and manufacturers’ technical staff remained at the commissioning site, forming a task force that carried out construction, commissioning, and modifications simultaneously. Through repeated evaluations, they overcame each challenge one by one, ensuring that the three units had all the necessary conditions for startup, ultimately achieving success on the first attempt. 　　In the absence of experience in building and operating large-scale units, as well as available technical data for reference, Tianzhi Chenye assigned professional technicians to form a project preparation team, implementing responsibility-based management in terms of safety, quality, schedule, and personnel. Tianzhi Chenye formulated and implemented a series of scientific and rigorous procedures for pipeline pressure testing, purging, commissioning, and startup, thereby ensuring the successful first commissioning of the air separation unit. These procedures laid the foundation for subsequent tasks such as purging external pipelines, installing packing, filling with perlite, and activating molecular sieves, thus accelerating the production of products from the air separation system. 　　It is reported that Tianzhi Chenye’s 100,000 tons per year ethylene glycol expansion project builds on the existing facility by making full use of calcium carbide furnace gas, waste coke powder, and organic wastewater for comprehensive resource utilization. By upgrading and expanding the facility for the production of 100,000 tons per year of ethylene glycol, Tianzhi Chenye will achieve an annual production capacity of 350,000 tons of ethylene glycol.