Points to note when changing the gas guide! !
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3 Precautions during gas introduction 1 Hazards that can occur during gas introduction: During gas introduction, the volume of gas is relatively small, while the cross-sectional area of the shift converter is large and its capacity is high. With a low gas volume, it is easy for certain \"dead zones\" to form within the shift converter; some gas accumulates in these dead zones and stops flowing, allowing conversion reactions or methanation reactions to take place there. This leads to an increase in temperature in those areas, eventually causing some of the catalysts to overheat, get damaged, agglomerate, and become inactive or unusable. 2 Correct gas introduction method: Gas introduction should be carried out slowly to prevent leakage from the heat exchanger head flanges and to avoid steam in the process gas from condensing and entering the first stage of catalyst, which could cause the surface of the catalyst layer to become powdered. To eliminate the drawback of a \"dead zone\" caused by low gas flow rate, an inert gas (N2) can be added to the process gas. This not only increases the gas flow rate and prevents the aforementioned problems but also allows the inert gas (N2) to carry away the heat generated during the sulfidation process, thereby preventing the bed temperature from rising too rapidly. Once the bed temperature returns to normal, gradually reduce the amount of inert gas (N2) used and increase the volume of process gas.
When introducing gas, the following points should be noted: 1. Adjust the temperature of the converter strictly in accordance with the specified heating rate; avoid overheating or temperature spikes, and ensure that the temperature is 20 degrees higher than the dew point at that pressure. No gas drift occurs; when gas flow is first initiated, the small volume of gas allows some nitrogen to be added to prevent drift. 2. Adjust the pressure of the converter by increasing it at a specified rate. 3. Water vapor ratio: When guiding gas, to avoid overheating, I believe the water vapor ratio should be higher than normal.
Our plant has not yet started operating. Personally, I think it’s necessary to reduce the water vapor content during gas guidance; the current value is 1.43, but we can lower it to 0.8 or 1.0. A high level of water vapor can increase the space velocity and help carry away heat, but it also raises the concentration of reactants, which is favorable for the occurrence of the conversion reaction and leads to an increase in bed temperature. Reducing water vapor content can help minimize the heat generated by the reaction. If the space velocity isn’t sufficient, N2 can be added. Please give me your advice
It’s mainly pressure, temperature stability, and control of the water vapor ratio, I guess
What is the gasification pressure for slurry coal gasification? Ordinary nitrogen can’t be introduced, right? Medium and high-pressure nitrogen is generally not used much (no pipelines available)? Or is the pressure low when guiding air? If you reduce the soda ratio, it’s necessary to lower the gas temperature as well; will the converter temperature still be able to remain stable under such conditions? Plugging in the electric stove again? In my opinion, for nitrogen circulation using a nitrogen circulation fan, once gas flow is initiated, this process continues while the outlet is gradually opened, until the nitrogen fan can no longer operate. Will this solve the problem of dead zones caused by insufficient air volume? Before starting up, what is the temperature of the waste boiler? And then how is that temperature controlled in order to lower the temperature of the gas? When the gas temperature is low, the water vapor content in the gas necessarily decreases, and the catalyst temperature must be reduced to the lower limit of its active temperature before the gas is introduced. These are just my personal opinions; I hope everyone can offer guidance
I studied everyone’s valuable insights carefully and gained a lot of knowledge
What is the gasification pressure for slurry coal gasification? Ordinary nitrogen can’t be introduced, right? Medium and high-pressure nitrogen is generally not used much (no pipelines available)? Or is the pressure low when guiding air? If you reduce the soda ratio, it’s necessary to lower the gas temperature as well; will the converter temperature still be able to remain stable under such conditions? Plugging in the electric stove again? In my opinion, for nitrogen circulation using a nitrogen circulation fan, once gas flow is initiated, this process continues while the outlet is gradually opened, until the nitrogen fan can no longer operate. Will this solve the problem of dead zones caused by insufficient air volume? Before starting up, what is the temperature of the waste boiler? And then how is that temperature controlled in order to lower the temperature of the gas? When the gas temperature is low, the water vapor content in the gas necessarily decreases, and the catalyst temperature must be reduced to the lower limit of its active temperature before the gas is introduced. These are just my personal opinions; I hope everyone can offer some guidance. Floor 5: It’s too dogmatic – how can low-pressure nitrogen not be introduced? When starting the gas introduction process, keep the pressure low; as the temperature rises, gradually reduce the use of low-pressure nitrogen. If the temperature rises too quickly, some medium-pressure nitrogen can be added
Maintain stable pressure to avoid significant fluctuations~
Yesterday, there was a problem with the purification process during gas introduction; when the volume of gas is low, some inert gas can be added. Pressure control can also be used again, which allows for the regulation of gas flow rate.
Reply to 3# Nightlight Cup: You haven’t started driving yet; a newly installed catalyst can only increase the water vapor ratio rather than decrease it. You’ll know when you drive. The pressure in the waste pot of your converter will be kept very low. Hehe. Practice tests theory
After a short-term parking period and when starting the vehicle again, the system first introduces nitrogen to lower the furnace temperature, and then removes it before introducing gas. What was said upstairs about removing nitrogen while allowing gas to pass through is not practical. With such high system pressure, the equalizing valve must be opened very gradually, which results in a very slow process – a huge discrepancy from actual operations!