In hydrocracking, why is demineralized water sometimes replaced by purified water for injection?
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This post was last edited by liaifeng on 2020-4-2 21:58. In hydrocracking, why is purified water sometimes replaced with brine? The water injection points are located before and after the heat exchanger. Solve!
Chloride ions and other substances present in the water, when combined with acidic gases such as hydrogen sulfide produced by reactions, form hydrogen chloride, which corrodes the heat exchangers. At the same time, the quality of the purified water is unstable; when chloride levels are high, it is necessary to switch back to using demineralized water for replacement. For normal industrial applications, it is recommended that the proportion of purified water used be ≤50%
Generally, water is injected before high-pressure air cooling; occasionally it is changed to before high-temperature heat exchange, also to prevent salt formation in the high-temperature heat exchange unit
It is recommended that demineralized water and purified water must pass analytical tests before they can be used; otherwise, the inlet pipelines of the injection pumps as well as the filters will suffer severe corrosion. This is for reference only!
Generally, demineralized water is used; for purified water, the chloride content requires close monitoring. Water injection is used to dissolve ammonium salts (ammonium chloride, ammonium hydrosulfide), as the precipitation temperatures of these two ammonium salts differ. When temperature changes occur due to process adjustments, in order to achieve the best results, the water injection amount is changed or adjusted according to the temperature at the injection point.
Generally, demineralized water is used entirely; improvement is recommended. When considering the situation before and after the heat exchanger, focus should be placed on scaling of the heat exchanger and the temperature level after heat exchange, with operations to be carried out based on actual conditions
What are the qualified standards for purified water? What level of CL roots is considered excessive? Are there any requirements regarding salt content and conductivity? Those who have used it before, please advise on how to restore it to normal