Discussion on nitrogen displacement in olefin projects

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Whether it is a new construction project or a major maintenance project, the issue of nitrogen purging of the system arises in both cases； The effect of system replacement determines whether the project can be completed on time and successfully brought online for operation; the number of replacement times also affects the economic efficiency of the plant’s operation. ? ? ??For example, when using a new project system for nitrogen purging, the following issues arise: To what extent needs the system to be pressurized? To what level should the pressure be released? How many times needs to be replaced? How much nitrogen is needed? Practical issues such as which pressure condition is most material-efficient to achieve the same effect need our attention. As required, the system is purged with nitrogen, resulting in an oxygen content of less than 0.2% (v/v) within the system. As can be seen from the table above, for the same pressure relief level, the better the purging effect as the pressure increases. With the same pressure, the lower the pressure release, the better the displacement effect. The data in the table above represent the displacement effect under ideal conditions; however, in actual production, it is greatly influenced by the pressure application point, mixing efficiency, and pressure release point. If the mixing effect is poor, with few or concentrated pressure relief points, the replacement effect will be compromised. Based on the comparative analysis of on-site samples taken after each replacement, the actual oxygen content after replacement is often much higher than the calculated value. For specific details and data analysis, please follow the WeChat official account: Chemical Engineering Work Notes