Factors affecting hydrogen recovery rate

1. The analysis system can use vacuum pumping, which enables more thorough analysis. 2. Depending on the system conditions, the amount of feed gas can be increased appropriately; meanwhile, analysis of the product gas should be intensified to prevent the product gas from being substandard. If there are online meters, pay attention to the trend changes of the online analysis instruments. 3. Also, extend the adsorption time as much as possible; at this point, samples from the final stage of adsorption can be taken for analysis. Since these samples represent the end of the adsorption process, if they meet the required standards, it ensures the purity of the product gas.

At higher pressures, the amount of hydrogen adsorbed also increases, so the losses increase as well； Together with the characteristics of the regeneration process, this results in a decrease in hydrogen yield; it can be seen that within a certain pressure range, as pressure increases, the amount of impurities adsorbed increases and thus the hydrogen yield improves. Furthermore, an excessively high adsorption pressure leads to a decrease in hydrogen yield. Therefore, the adsorption pressure is not the higher the better. The adsorption pressure of PSA in hydrogen production units is generally designed to be around 2.3 MPa. The purge pressure is the exhaust gas pressure; the lower the purge pressure, the higher the hydrogen recovery rate and the better the regeneration of the adsorbent. Conversely, the higher the purge pressure, the lower the hydrogen yield; however, considering that the waste gas must be able to be sent directly to the converter as fuel, the outlet pressure of the waste gas buffer tank must be maintained at a minimum of 0.03 MPa (gauge). Why is it necessary to adjust the adsorption time based on the amount of feed? Answer: Under certain product specification requirements and a specific amount of adsorbent, each adsorber has a fixed maximum amount of impurities that the adsorbent can absorb. Therefore, each adsorption step can only purify a certain amount of feed gas. At a certain feed flow rate, if the adsorption time is too long, the adsorbent will absorb excessive amounts of impurities, resulting in impurity overload. This not only reduces the purity of the product but also deteriorates the operational performance of the PSA system. If the adsorption time is too short, the adsorbent cannot be utilized fully, resulting in a failure to achieve the desired hydrogen yield and causing waste. Therefore, the adsorption time should be adjusted appropriately based on the actual feed flow rate, so as to make full use of the adsorbent and achieve a high hydrogen yield while ensuring product purity and protecting the adsorbent. Therefore, increasing the \"operation coefficient K\" means extending the adsorption time in proportion. Effect of operating coefficient on PSA unit operation: ☆Increasing the operating coefficient → longer adsorption time → lower product purity → higher hydrogen recovery rate ☆Decreasing the operating coefficient → shorter adsorption time → higher product purity → lower hydrogen recovery rate

True adsorption time, equalization step