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Successful completion of \"bare cooling\" for the air separation unit in Lean Chemical Hydrogen Production Center / Author/Source: Gas Separation / Date: 2020-01-03 / Clicks: 6 On January 1, 2020, the \"bare cooling\" process for the air separation unit in Shaanxi Lean Chemical Co., Ltd.’s hydrogen production center was successfully completed, marking another important step forward in integrating this unit into the entire production process. This development creates favorable conditions for the unit to start operating as soon as possible and to produce qualified products. At 8:30 on December 27, 2019, as the humming sound of the compression units in the air separation unit sounded once again, another important stage in the commissioning of this unit was reached – the \"bare cooling\" phase. This cold-trapping process was carried out in three stages: In the first stage, the medium and high-pressure air pipelines in the air separation unit were purged, the oxygen pipelines were purged, and the tower was purged and heated. Through successive purging operations and testing, and further purging and testing until the test results were satisfactory, the piping system was resumed for normal operation. Finally, at 22:00 on December 31, 2019, all dew point measurements within the cryogenic tank system came back within acceptable limits ； In the second phase, for the cold tower, at 22:15 on December 31, 2019, the booster turbine expander was started to carry out comprehensive cooling of the cold tower ； In the third phase, an inspection was carried out inside the cryogenic tank. At 14:00 on January 1, 2020, personnel were sent in to check for leaks in the cryogenic tank system; the inspection using bare cooling was completed by 17:00 on the same day, with no leaks detected, which indicated that the \"bare cooling\" operation of the air separation unit had been successfully completed. Once the \"bare cooling\" phase of the air separation unit is completed, work such as the removal of the scaffolding inside the cold box and the filling with perlite will be accelerated, thereby moving forward toward the completion of the entire process associated with the air separation unit and its early commissioning. It is reported that the coal tar deep processing and multi-product integrated utilization project of Shaanxi Jingyi Chemical Co., Ltd. is currently the first large-scale coal-based aromatic hydrocarbon production line in China. It achieves comprehensive and systematic utilization of coal based on its different quality levels, representing a new industrial approach to the conversion and utilization of coal. The total investment in the project is 4.6 billion yuan, and it mainly includes a 550,000-ton/year coal tar pretreatment unit, a 500,000-ton/year coal tar fluidized-bed hydrocracking unit, a 450,000-ton/year coal tar fixed-bed hydrocracking unit, a 400,000-ton/year naphtha continuous reforming unit, a 170,000-ton/year aromatic extraction unit, a 50,000 m3/h coal-to-hydrogen production unit, a 50,000 m3/h air separation unit, a 100,000-ton/year methanol synthesis unit, as well as related supporting facilities such as hydrogen purification (PSA) units, sulfur recovery units, phenol-amine recovery units, storage and transportation systems, and other auxiliary and environmental protection systems.