关键词: 热联合, 节能优化, 热泵精馏, 间接蒸汽压缩法

Abstract:

Heat pump distillation is applied to the heat combination between the diesel hydrogenation unit and dry gas concentration unit in a refinery. The medium-water is used to absorb the heat of the gaseous oil at the top of the product fractionator of the diesel hydrogenation unit. After the medium-water is vaporized and pressurized for temperature raising, it is sent to the C₄ absorption tower reboiler and C₄ desorption tower reboiler of the dry gas concentration unit, so as to save the steam. Through optimization, the temperature of the gaseous oil at the top of the fractionator after heat exchange is controlled to 130℃, the pressure of the steam after compression is 278.4kPa, and the compression ratio is 1.43. And the process of double flash tank is innovatively adopted to avoid using water cooler to cool medium-water, which can save 20t/h circulating water and recover 0.2t/h steam. The heat in the diesel hydrogenation unit was recovered by 6.93MW, and the steam was saved by 11.5t/h. The annual operation cost is saved by 7.652×10⁶CNY compared with the original system, and the energy-saving benefit is 50.66%; the annual energy consumption is saved by 4944.0t EO, and the energy saving amount reaches 70.93%.

Key words: heat combination, energy saving optimization, heat pump distillation, indirect vapor compression