Adjustment measures for water-chlorine balance
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Under Diagnosis Results/Actions: The system is too dry; increase the water injection volume to bring the water content in the circulating air to the required level. The system is too humid (1): If the water content in the circulating gas exceeds 50 ppm, lower the reactor’s inlet temperature to below 480°C ； (2) Check the reasons for the high water level in the system, and inspect and adjust the operation of the evaporation dehydration tower ； (3) Put the molecular sieve drying tank into operation and increase the chlorine injection amount appropriately ； (4) After the water content in the recycle gas returns to normal, it is necessary to carry out catalyst chlorination for a certain period of time. Additionally, depending on the recovery of the catalyst’s activity, the reaction temperature should be gradually increased until it reaches normal levels. The chlorine content is too low (1). First, determine whether the low chlorine content in the catalyst is due to insufficient chlorine injection or high water content in the gas ； (2) If the cause is chlorine loss from the catalyst due to high water content in the circulating gas, the measures outlined in the “System too wet” section above can be applied ； (3) If the reason is a low chlorine injection rate, the chlorine injection rate can be increased to adjust the water-chlorine ratio. Excessively high chlorine content reduces the chlorine injection rate and increases the water-to-chlorine molecule ratio
When there is a imbalance of water and chlorine in the reforming catalyst, it is necessary to conduct a comprehensive analysis of the various symptoms exhibited by the plant. By examining these phenomena from the perspective of the reforming reaction mechanism, their causes can be identified and appropriate measures taken; otherwise, conclusions that are completely opposite to the actual situation may be drawn. This is because situations where the same phenomenon occurs due to different reasons happen from time to time. For example, a decrease in the temperature drop in the last reactor during reformation can be caused by two types of overly intense reactions: one is an intensified exothermic hydrocracking reaction, that is, an enhanced acidic activity of the catalyst, which leads to a decrease in the temperature drop ； Another option is to enhance the exothermic hydrolysis reaction, that is, to improve the metallic functionality of the catalyst, thereby reducing the temperature drop. Obviously, the approaches to dealing with these two situations are completely different; the former is caused by an excessive chlorine content, and it is necessary to reduce that chlorine content ； The latter is caused by too low a chlorine content, and it is necessary to increase the chlorine content. On the other hand, further analysis is required for each case; for example, in situations where the chlorine content in the catalyst is too high, the reason for this may be an excessive amount of chlorine added, along with appropriate levels of water in the gas ； It is also possible that the chlorine injection amount is appropriate while the water content in the gas is too low. This requires further diagnosis based on changes in C3/C1, as well as a differential analysis of various other symptoms in order to reach a correct conclusion.