The compressor heat exchanger has poor heat exchange efficiency and internal leakage
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This post was last edited by leo_0088 on 2020-7-9 at 16:12. The primary and secondary coolers of the compressor have a heat exchange area of 14 square meters, and the cooling water pressure is 2 KG. After the compressor was in operation for a month, it was shut down for several months; during that time the cooling water supply was not turned off. When it was used again, it was found that the flow meter rotated very slowly and the heat exchange efficiency was poor. The material of the heat exchange tubes is carbon steel (20#), and the circulating water is tap water that has been treated with chemicals such as sodium hypochlorite – the analysis results showed that everything was within acceptable limits! Later, an internal leak was detected, so stainless steel heat exchange tubes were planned to be used. Upon removal, the following situation was found:
In a compressor inter-stage cooler, the gas pressure is generally designed to be higher than that of the cooling medium. So under normal circumstances, gas leaks into the shell side! In the case described by the poster, there is leakage on one hand, and the water quality is also a serious issue: corrosion occurs, scale builds up, the flow rate decreases, which makes it easier for more scale to accumulate, and corrosion worsens further – it’s a typical vicious cycle!
Shell-side cooling water, tube-side process gas
Water has had chemicals added to it and was tested; aside from slightly high levels of iron ions (which are within the acceptable range), the water quality meets the standards
Gas leaks into the shell side, where it partially dissolves in water to form a weak acid that corrodes the pipes, with the corrosion products continuously accumulating But you have a bit too much of this corrosive substance, don’t you? . . . .
My medium is high-purity hydrogen, so there should be no corrosion
The water quality is satisfactory, and the medium is high-concentration hydrogen gas; hydrogen is practically insoluble in water. Hydrogen reacts with chlorine only when ignited. It seems that corrosion occurred despite these conditions not meeting the requirements for corrosion to take place – how can this be explained? I @WangWei2, let’s see how the experts analyze it
In fact, this is the result of long-term corrosion caused by water remaining in the housing when it was taken out of use. If this situation occurs, be sure to remove the moisture; this way, corrosion will not occur as quickly.
It seems that details determine success or failure.