Lockhopper circulation pump flow rate
Thread Content
The hopper circulation pump draws water from the top of the hopper, pressurizes it, and sends it back to the quenching chamber of the gasifier; from there, the water flows back to the hopper, thus creating a cycle. This circulating water carries the slag at the bottom of the quenching chamber to the hopper, preventing it from accumulating and causing blockages. Most of the lock hoppers used in Texaco’s gasification plants follow this process, but the flow rate and head of the lock hopper circulation pumps vary. Taking a furnace with dimensions of Φ3200/3800 and a lock hopper volume of 13.5 cubic meters as an example, there are at least two possible configurations: 1) The lock hopper circulation pump uses a pump with a head of 30 meters and a rated flow rate of 30 m3/h, with 4-inch inlet and 3-inch outlet pipes. 2: For the lock chamber circulation pump, a pump with a head of 60 meters and a rated flow rate of 80 m3/h is selected, featuring 6-inch inlet and outlet pipes. Of the two configurations mentioned above, the first one results in lower flow rates, lower head pressure, less slag and water flow, thus reduced energy consumption and less pipe wear. However, it is not conducive to slag removal from the quenching chamber, especially in gasification furnaces equipped with slag breakers. The pump in the second configuration has a high flow rate and high head, which is beneficial for slag discharge, but it causes severe pipe wear. So I’d like to ask everyone to discuss how you choose the flow rate and head for your respective gear pump circulators How is the application performing?
It is up to the designers’ own understanding; there are no uniform rules
Poor slag discharge directly affects operation； Pipe wear should be resolved by inspection and replacement.
A 3.2m furnace, with a silo of 24 cubic meters; the silo circulation pump has a rated flow rate of 81 cubic meters and a head of 39m. It seems that slag flushing isn’t a problem, but wear is indeed quite severe. Regular thickness measurements can help address this issue. The most troublesome thing is when there’s suddenly a leak in the bottom area of the gasification furnace
It’s better to have a higher traffic volume. . . . . .
I personally think the same way; our old factory used pumps with high flow rates and slightly higher head. When I switched to the new factory, I was confused by these parameters. When I went to the design office to have the drawings reviewed, they said it was an improvement measure, but they didn’t explain exactly what the advantages were.
No matter how it’s calculated, the head cannot reach 60 m; during circulation, the pressure difference between the lock hopper and the vaporizer is very small.
This post was last edited by xklcj on 2015-8-10 at 11:08. I can fully understand why a lower head value was chosen; in our previous factory, we used pumps with a head of 60 meters, and as a result we didn’t dare to open the outlet completely – during normal operation, the opening degree was less than 30 percent, as opening it fully would cause the flow rate to exceed the maximum allowable level. However, by closing the outlet valve to build up pressure in this way, the valve element wore out after a short time. Eventually, a homemade flow-limiting orifice plate was installed at the outlet, and this homemade orifice plate was replaced regularly; this approach is much cheaper than replacing the valve. For this type of gear-driven circulation pump, a high head value is chosen; I guess it’s not just one or two companies that do this – there are probably others who have encountered this issue as well. New factories these days probably won’t choose such a high head value anymore; currently, the head values are likely in the range of 20–40 meters!
Our head is not very high; as for the flow rate, it becomes too high and causes the pump to overload, so we added a flow control orifice plate
Is the flow rate too high when the outlet valve is fully open, resulting in overload, or is it because the head is too high?