Requirements for water vapor ratio control during system pressurization after the gasification furnace is started up
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This post was last edited by wang06120325 on 2015-9-29 at 16:37. After the vaporization furnace was put into operation and gas was introduced into the downstream system, there were several instances of excessive temperature in the bed layers; apart from the factor of too fast gas introduction speed. In my opinion, it is also closely related to changes in the water vapor ratio. At the beginning of operation of the system, the temperature of the entire water circuit rises slowly; as a result, the temperature at the inlet of the cooling water pump is low, and the water vapor ratio cannot increase. During the gas-liquid mixing process, the water vapor ratio begins to rise gradually. If the reaction rate in the furnace becomes too fast, a large amount of reaction heat is generated, which can easily lead to overheating of the bed layer. I wonder what the water vapor ratio is generally maintained at when other units are operating under pressure, and whether this phenomenon has occurred before.
This post was last edited by jensse on 2015-9-29 at 19:29. In fact, controlling the water-gas ratio is very important; generally, after the pressure increase in the gasification unit is completed, the temperatures of various waters are adjusted gradually. The water-gas ratio should reach the designed value before gas is sent to the shift reactor. The reason for this is that after the shift system stops operating, the temperatures of the surface of the shift furnace and its pipelines drop. At the beginning of gas flow, the temperature of the incoming gas decreases, causing the temperature of hot spots to drop as well. Additionally, since the temperature of certain layers in the catalyst bed falls below the active temperature for a short period of time, the shift reaction occurs mainly in those layers that still have an active temperature, which leads to overheating of the catalyst bed. In such cases, a higher water-gas ratio helps – an increased space velocity due to this higher ratio facilitates a quicker recovery of the catalyst bed’s temperature (by accelerating the transfer of heat in and out), thereby preventing the catalyst from remaining under high temperatures for extended periods.
Well, individuals also tend to see the water vapor ratio approach the designed value when backward system gas integration occurs; moreover, increasing the gas integration speed appropriately during this process can also effectively prevent overheating of the bed layer. When the gas flow rate to the conversion system increases, the space velocity rises, which also helps to remove the reaction heat quickly; otherwise, once the temperature of the entire bed rises, it is difficult to lower that temperature in a short time. There is a balance point between the heat generated by the syngas entering the system and the heat removed from it; only by rapidly approaching this balance point can overheating of the bed be avoided, as overheating of the bed may lead to another degassing process.
Such problems can occur; before proceeding with the gas conversion, it is necessary to control the parameters required by the process. By \"water-vapor ratio,\" what is meant is the control of the temperature at the outlet of the scrubber. In fact, the washing of syngas in the scrubber is a process that results in a reduction of the water-vapor ratio, and this aspect needs to be properly managed. So things will get better after summarizing experience; this kind of problem occurs to some extent on the first try, and it’s good to summarize more often