TAXECO Gasification Consulting

The idea upstairs is interesting; it shows you’ve used some thought, but I’d like to share my perspective. Firstly, the pressure of the gray water sent to the carbon scrubber tower is relatively low, while the pressure of the black water going to the venturi and the quench ring is higher. The volume of water flowing into the venturi is less than that of the gray water sent to the carbon scrubber tower. If a portion of the gray water is sent directly to the venturi, it means that the outlet pressure of the pump will have to increase further; the additional energy supplied to this portion of gray water is equivalent to the energy provided by the black water circulation pump for that water. However, for the other portion of gray water that goes directly into the carbon scrubber tower, the extra pressure applied results in an energy waste. The black water circulation pump primarily serves to increase pressure; the pressure difference between its inlet and outlet is not high, and its design and manufacture are not particularly difficult. There is little practical value in doing this; it not only fails to save energy but also increases energy consumption, so I think it is not a good idea.

Thank you for the response from the second floor. After some thought, in a venturi system, the flow velocity of water at the throat is generally high, and the amount of water entering the venturi is slightly less than that of the high-pressure return water, around 15–20%. Is it possible to send all the graywater into the venturi and increase the pressure slightly? Currently, the pressure is about 1 MPa higher than that of the gas; if it is increased by 0.5 MPa, it should have little effect on the flow velocity

The key issue is that with the current 2800 gasification furnace, the water flow rate of the circulating black water pump is around 250 tons per hour; if the capacity increases, such as when the coal feeding rate reaches 2000 tons per day, selecting an appropriate pump becomes a problem

Will using high-pressure gray water in the venturi necessarily raise the liquid level in the scrubber tower? It seems to depend on the amount of graywater used; additionally, the humidification in the venturi also serves to help the gas reach its saturation level. This is just my personal opinion.

In fact, it has no impact on the liquid level of the carbon scrubber; the total amount of material entering and leaving the carbon scrubber remains unchanged – it’s just the location of one of the feed streams that has changed. Furthermore, the head of black water circulation pumps is not high in reality; there are no significant difficulties in selecting pumps with high flow rates and low heads. Furthermore, for a venturi that has already been manufactured, the fluid flow rate is related to the pressure difference generated; as the flow rate increases, the pressure difference rises even further, unless the venturi is redesigned. Personally, I think the design of this process is quite reasonable, and there’s no need for any changes.

Do you feel that the venturi effect helps to remove dust and reduce temperature? Some say that the effect of the venturi is not significant; it’s not very noticeable, and it’s mainly the carbon scrubber that does the job

The gas-liquid mixing effect in the venturi determines the efficiency of syngas washing; it can be said that gas-liquid contact via the venturi results in fairly thorough mixing, with the majority of fly ash being washed into the black water at this stage. In contrast, the washing effect of the water used in the lower part of the carbon scrubber is much weaker. The gas-liquid contact efficiency in the tray section should be good as well, but it is not possible to handle large amounts of fly ash here; otherwise, there will be problems with tray blockage, and it will also be difficult to keep the amount of fly ash entrained in the downstream stream within a reasonable range. Therefore, the venturi plays a relatively important role in wet scrubbing; it is what ensures the ultimate cleaning efficiency of the carbon scrubber tower.