关键词: 歧化装置, 板式换热器, 清洗, 烧焦, 碱洗, 漂洗, 真空气密

Abstract:

The feed plate heat exchanger of a certain disproportionation unit experiences fouling on both sides of the plate after multiple cycles of operation, resulting in a significant decrease in heat transfer efficiency and an abnormal increase in fuel gas consumption. The cold end pressure difference of the plate heat exchanger reaches 98% of the design value, which can not continue to improve the load of the unit, seriously restricting the long-term stable operation of the device. In order to reduce the pressure difference of the plate heat exchanger and restore its heat transfer efficiency, it is necessary to clean or scorch it. This paper introduces a treatment technology of alkali washing, rinsing and controllable combustion scorching. The salts existing in the reaction feed heat exchanger of the disproportionation unit are removed by chemical cleaning, avoiding the corrosion risks that may be caused in the process of scorching and internal inspection. By controlling the amount of low concentration of air in the scorching process, the intensity of the scorching is controlled to remove the coke inside the plate heat exchanger. The cold end pressure difference of the plate heat exchanger under the same load decreases from 188 kPa to 45 kPa, the hot end temperature difference decreases from 51.9 ℃ to 31.0 ℃, and the fuel gas consumption of the reaction heating furnace decreases by more than 50%. It can achieve the effect of restoring the design capacity of the plate heat exchanger by more than 95%, reducing the energy consumption of the device, and eliminating the bottleneck of the device operation.

Key words: disproportionation unit, plate heat exchanger, cleaning, scorching, alkali cleaning, rinsing, vacuum airtight