Principle of constant current at critical compression ratio
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I am not from a instrumentation field. The backflow method is mentioned in the measurement of pressure differences in hydrogenation reactors; its principle is based on the concept of critical compression ratio constant flow. Could someone explain in detail what this concept entails? Please avoid answers from Baidu
What major is the original poster in? This concept is mentioned in the principles of chemical engineering: bubbles form upward beneath the liquid surface, and when uniform bubbling occurs, it indicates that the pressure at the inlet and outlet is balanced. The method for measuring the backflow pressure difference is somewhat similar to this; in China, rotameters are generally used for adjustment, while in foreign countries, flow-limiting orifice plates are more commonly used. I originally had some calculation documents, but I lost them over time. In environments with high temperatures and strong corrosivity, back-pressure indirect measurement is used to determine the blowing pressure, which is approximate to the actual process pressure.
Hello, I specialize in equipment; I’m not very familiar with instrumentation. In our hydrogenation reactors, the differential pressure is measured by introducing hydrogen gas, and the flow rate is controlled using orifice plates. The differential pressure gauge does not come into direct contact with the medium itself, but rather measures the hydrogen gas used for purging. Is this principle the same as what you mentioned?
Hello, I specialize in equipment; I’m not very familiar with instrumentation. In our hydrogenation reactors, the differential pressure is measured by introducing hydrogen gas, and the flow rate is controlled using orifice plates. The differential pressure gauge does not come into direct contact with the medium itself, but rather measures the hydrogen gas used for purging. Is this principle the same as what you mentioned?
Yes, a flow-limiting orifice plate (within a certain differential pressure range) can ensure that H2 enters the reactor at a constant rate, thereby maintaining pressure balance. If the flow-limiting orifice plate is properly selected and matched to the current pressure conditions, the accuracy can reach around 2%, or even better.
The control of the air flow rate is achieved by allowing a small amount of bubbles to escape from the lower end of the pressure guide tube. To ensure stable airflow, the ratio of the absolute pressure of the fluid flowing through the throttle element to the absolute pressure of the fluid before the throttle element should be less than or equal to the critical compression ratio – thereby ensuring stable flow rate.