【Weekly Topic】On the downcomer and upcomer of water-coal slurry gasifiers
Thread Content
The quench chamber of a water-coal slurry gasifier contains downcomers and upcomers; these were also present in the Texaco and diversified slurry gasifiers. The downcomers are used to guide the gas from the combustion chamber into the quench chamber, where the quench water forms a water curtain along these downcomers. So what is the specific function of the upcomers? Just to guide the gas upward? Later, in furnaces with multiple nozzles and most dry coal powder systems, the rising tube was removed. What are the advantages and disadvantages of removing the rising tube? Everyone is welcome to speak up and discuss actively
As far as I understand, the function of the rising tube is to guide the gas upward, allowing it to rise smoothly rather than violently; this helps to reduce the amount of water carried along with the gas and to suppress severe fluctuations in the quenching chamber. Therefore, the descending tube is generally shorter than the rising tube, so that the gas guided down by the descending tube can rise directly along the rising tube. However, if the annular gap distance between the rising pipe and the descending pipe is insufficient, it will have the opposite effect; the disadvantages for the gasification furnace will outweigh the advantages, and the quenching chamber will be more prone to carrying water. If the annular gap distance is too large, the function of the riser is not realized; instead, it becomes something unnecessary. So after removing the riser tube, I’m still skeptical as to whether it really can reduce water entrainment as claimed; I wonder if anyone has conducted research on this topic. I feel that without the rising tube, fluctuations in the quench chamber should also be more likely to occur.
In the past, I read papers written by other manufacturers on the subject of expanding the diameter of upward-flow tubes in order to reduce water contamination in syngas. I wonder if any of you here have experienced this firsthand.
In my opinion, the rising pipe cannot be removed; otherwise, air flow fluctuations will be excessive, and it will also be difficult to control the liquid level in the vaporization furnace. The probability of false liquid level readings increases as well
It is designed with an upward tube: the reason is 1, to stabilize the air flow. 2. Reduce water and ash content. 3. Extend the service life of the washing tower trays and demisters. 4. Growth transformation operation cycle. 5. Stabilize the liquid level in the gasification furnace. 6. Reduce the probability of synthesis gas blockage at the outlet of the gasifier.
The Texaco gasifier in our plant consists of a downcomer connected to an upcomer, but can the narrow annular gap allow all of the syngas to rise through it? I just can’t believe it
The Jinhua furnace in our factory doesn’t have an upward tube; it only has a downward tube
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