【2026 Heat Exchangers】The fluid at the outlet of the heat exchanger shell side contains liquid

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What causes the fluid to be present in the outlet stream of the heat exchanger shell side (for example, when the amount of liquid in a gaseous stream exceeds 5%)? How to solve it? Liquid present at the shell side outlet can cause failures in downstream equipment (such as damage to compressors due to liquid presence, or disruptions in reactions caused by liquid in the reactor feed). The main reasons for this are inadequate gas-liquid separation or chaotic flow patterns; to address this issue, it is necessary to optimize the separation structure and adjust the operating parameters. Common causes: ① Improper design of the shell-side baffle (excessive spacing, insufficient gas-liquid residence time, reduced separation efficiency) ； ②The flow rate of the medium in the shell side is too high (gas flow rate exceeds 3 m/s, enhancing the ability to carry liquid) ； ③There is no gas-liquid separation device in the shell side (such as a demister or liquid baffle), so it is unable to trap any entrained liquid. Solution: ① Modify the baffle (reduce the spacing to 1–1.5 times the pipe diameter to increase the gas-liquid residence time) ； ②Reduce the flow rate of the medium in the shell side (e.g., by reducing the feed volume or increasing the flow area in the shell side) ； ③Install a demister (such as a wire mesh demister with a separation efficiency of over 98%) or a liquid baffle at the shell-side outlet.