【Haichuan Chemical Industry News】Water ring vacuum pumps replacing two-stage steam jet pumps in primary vacuum towers to reduce steam consumption in the facility

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Original title: Yangzi Petrochemical optimizes plant processes to promote energy conservation and environmental protection. Date: 2016-12-19. Source: Petrochemical News. Recently, the mechanical vacuum extraction (vane pump) system for the primary vacuum tower of Yangzi Petrochemical’s No. 2 atmospheric and vacuum distillation unit was successfully put into operation, and the mechanical vacuum extraction system is functioning stably. To date, both the primary and secondary vacuum towers of Unit 2’s atmospheric and vacuum distillation unit utilize liquid ring pumps for vacuum creation, resulting in significant energy savings; the annual economic benefit of this unit amounts to 3.12 million yuan. Previously, the primary vacuum tower of Yangzi Petrochemical’s No. 2 atmospheric and vacuum distillation unit used steam jet pumps for vacuum creation, which required a large amount of steam. Steam consumption is the third largest source of energy consumption for the plant, after fuel and electricity usage. The steam also needs to be cooled, resulting in a high cooling load at the top of the tower, which requires a large amount of circulating water. The acidic water resulting from vacuum steam cooling further increases the burden on wastewater treatment. At the same time, steam evacuation is affected by fluctuations in steam pressure, resulting in large variations in the vacuum level at the top of the unit, which affects the stable operation of the equipment. In this technical upgrade, a set of water ring vacuum pumps is used to replace the two-stage steam jet pumps in the primary pressure reduction tower, thereby reducing the steam consumption of the plant. The gas from the first stage of pressure reduction is cooled in the pre-condenser EA2108; thereafter, the gaseous phase enters the water ring vacuum pump and is discharged into the compressor system after passing through that pump. When the unit is operating normally, only one water ring vacuum pump is used for vacuum extraction at the top of the primary pressure reduction tower, while the existing steam jet pump serves as a backup only in case of a failure of the mechanical vacuum pump. It is estimated that after its operation, the two constant-pressure units alone can reduce steam costs by 2.1798 million yuan per year, thanks to the use of just one pressure reduction tower ； Annual savings of 75,600 yuan in acidic water treatment costs, **contributing to the energy efficiency and environmental protection of the facility. Meanwhile, Yangzi Company also formulated the \"Commissioning Plan for the New Mechanical Vacuum Extraction System in Unit 2’s Atmospheric and Vacuum Distillation Unit.\" It arranged for relevant training on the procedures and operations to be provided to the operators during their shift replacement periods. Additionally, the \"Commissioning Plan for the New Vacuum Extraction System\" was included in the CPMS training materials so that operators could study it on their own. Before the system was put into operation, all operators of Unit 2’s Atmospheric and Vacuum Distillation Unit were tested on the relevant knowledge. To ensure the successful commissioning of the mechanical vacuum extraction (liquid ring pump) system for the primary vacuum distillation tower. (Gu Jingyang, Wu Jun)