Reason for introducing nitrogen while raising the steam temperature in the conversion system
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In the methanol production project using coke oven gas, during the steam heating process of the conversion system, a certain amount of nitrogen is introduced at the outlet of the gas-liquid separator to maintain an outlet pressure of 0.1–0.2 MPa in the initial stage and around 0.5 MPa later on. I would like to ask the experienced sailors here if anyone knows the reason; I hope you can kindly share your insights. I thank you first, sir.
Why isn’t anyone responding? Master, please help!
Protective effect: Participates in circulation to increase blood volume
Please ask the old moderator to explain in more detail. During the heating process of the converted steam, by the time it reaches the gas-liquid separator, it has completely condensed into water ； And nitrogen is also added only after the gas-liquid separator; I’m still not quite clear as to how it participates in the cycle
Generally, a certain amount of nitrogen is introduced at the inlet of the conversion system, allowing steam to flow smoothly through the converter while maintaining stable pressure and ensuring high controllability. When using steam alone, it is difficult to control the pressure; once all the steam condenses, the pressure in the system is not sufficient to push the separated water out, so some nitrogen remains in the system. The original poster is asking if your nitrogen is recycled If it’s not a loop, then it’s unclear why it’s placed after the separator
It is easy to understand why nitrogen is introduced at the inlet of the conversion system. After our gas-liquid separator, and before the vent valve of the conversion system, there is a dedicated nitrogen pipeline that is used to supply nitrogen when heating the steam; in my opinion, it does not participate in the steam circulation process for heating. If no nitrogen is added, the outlet pressure of the conversion system is almost zero. Hearing you say that reminds me – is adding nitrogen simply to facilitate the smooth drainage of the steam condensate? Because when our conversion system is operating normally, the condensate phase from the gas-liquid separator is not sent to the circulating water system; instead, it is pressurized to 2.8 MPa by a pump and sent to the stripping tower ； Therefore, during the steam heating process, the condensate coming from behind the gas-liquid separator is discharged directly to the drain through a bypass pipeline, which often results in delayed drainage and excessively high liquid levels; as a result, it becomes necessary to open the low-point drain valves on the gas-phase pipelines of the final cooler and the desalinated water cooler to remove the condensate.
1. If the temperature is too low in the early stage, the steam added is likely to condense within the catalyst layer; it is necessary to ensure that the system temperature remains above its dew point. . . 2. Steam condensation occurs later on, and negative pressure may arise; the purpose of making up steam is to maintain system pressure. . . An outsider’s perspective
No additional nitrogen is required. For the heating process during conversion, air or nitrogen is used to raise the temperature first; once the temperature has increased, medium-pressure steam is introduced
It might be due to different manufacturing processes, or I just didn’t understand it. Under normal circumstances, to increase the temperature of the conversion steam, the conversion system requires high flow rates and low pressure, so as to enable rapid temperature rise in the conversion furnace. To prevent water blockage caused by steam condensation, the heating steam is generally vented near the boiler feedwater preheater, and gas is directed further downstream only after successful ignition. The steam condensate is first discharged into the gutter, and only when pressure builds up is it sent to the circulating water system or other processes. Why is the pressure at the conversion end set at 5 kilograms?