The BDO steam condensate waste heat recovery system of Shaanxi Chemical Industry has been successfully put into trial operation

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The waste heat recovery system for BDO steam condensate at Shaanxi Chemical Industry has been successfully put into trial operation. Author/Source: Shaanxi Chemical Industry. Date: May 10, 2021. Clicks: 10. On May 7, good news came from the production site of the BDO plant – the newly installed lithium bromide unit was started up successfully in one attempt and brought online. After nearly a day of trial operation, the lithium bromide unit met the system’s cooling requirements, marking the success of the BDO steam condensate waste heat recovery technology upgrade project. This technical upgrade project adopts the Energy Management Contracting (EMC) model, using the 120°C steam condensate recovered from the production of BDO and PTMEG as a heat source to drive lithium bromide refrigeration units, which generate 5°C chilled water. This approach replaces the 6000V/630KW centrifugal ethylene glycol chiller units, thereby reducing operating electricity consumption and also lowering the thermal load on the circulating water system in Phase II. The original centrifugal ethylene glycol chiller units can serve as backup units for the lithium bromide refrigeration systems. Lithium bromide units utilize the phase change of water at low pressure (from liquid to gas) to absorb the latent heat of vaporization, thereby achieving cooling; in this process, water serves as the refrigerant, while the lithium bromide solution acts as the absorbent. This technical improvement project was approved and launched in September 2020, with the Production Department taking the lead in organizing and coordinating the efforts. In February of this year, external contractors began the on-site installation work. The relevant parties cooperated actively to ensure that all tasks, including factory renovation, foundation construction, equipment installation, pipeline connection, electrical and instrumentation work, and unit testing, were completed safely without disrupting normal production. At 16:00 on May 7, the unit was fed with circulating water, 5°C water, and condensate; joint commissioning began and the unit came online. Meanwhile, the ethylene glycol unit was shut down step by step, while the lithium bromide unit operated independently. Currently, the lithium bromide chiller unit is equipped with a outlet water temperature setting of 3.5–5°C; an automatic control valve is used to adjust the amount of condensate in order to regulate the cold water outlet temperature. After 72 hours of operation, the temperature remains within normal ranges, satisfying the cooling capacity requirements of the BDO system. Referring to the hourly operating power of 580.29 KW of the chiller before the technical upgrade, it is estimated that the upgrade will result in energy savings of 13,926 kWh per day, leading to cost savings of nearly 7,000 yuan in electricity expenses. The electricity consumption per ton of BDO decreases by about 34 kWh, which not only enables effective use of energy in the system but also enhances the competitiveness of the company’s products. Going forward, Shaanxi Chemical Industry Company will also carry out various energy-saving renovation projects, including energy-saving upgrades to the circulating water system in Shaanxi Blower Group’s air separation units, as well as waste heat power generation systems for the BDO distillation process. Leverage current advanced technologies to generate benefits for the company and help it stay at the forefront in terms of energy efficiency for various products.