Selection of gas scrubber towers
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For the gasification process, gas washing is inevitable; every gasification technology utilizes this unit operation. As for the type of tower used, there are generally empty towers, packed towers, and tray towers. Now, classmates from Haichuan who are in factories, could you tell us what type of scrubber towers your factories use?
Good point; we use sieve plate towers, and sometimes the sieve plates turn over
Spray towers. And hot water evaporation towers
There are those with trays; this post was last edited by Langtaosha on 2008-4-23 at 21:44.]
Do sieve plate towers have the problem of flooding?
You can search online for information on the water-coal slurry gasification process used at East China University of Science and Technology; there is a specialized gas washing system for that purpose. I work in the field of gas purification.:handshake
Currently, for atmospheric pressure gasification, either empty-tower spraying or packed towers are used; however, packed towers are prone to clogging, which leads to an increase in system resistance and is not conducive to gas-liquid contact. Pressurized gasification generally employs sieve tray towers or bubble cap towers, which have low pressure loss and whose washing efficiency meets the purification requirements. As long as the resistance is not high, operations are carried out normally, the type of coal does not change much, the sieve plates are thoroughly cleaned during maintenance, and a moisture separator is installed before making any changes, normal production can generally be maintained even if there is liquid flooding, as long as it is addressed promptly.
Our company’s fluidized bed process consists of 2 1.8-meter cooling towers (with stainless steel structured packing) + 1 3.6-meter cooling tower (equipped with PVC structured packing)
Our gas scrubber is a tray tower; the raw gas is first washed in a water bath, after which the gas flows upward and is further purified by high-temperature condensate introduced onto the trays at the upper part of the scrubber. It then passes through a wire mesh demister before proceeding to the next stage.
When choosing a gas scrubber, one important aspect is preventing blockages. The gas washing tower used for fixed-bed gas production in our factory was initially empty; later, bamboo plate packing, ceramic structured packing, and plastic grid packing were used. Currently, the latter two types are the main ones in use, and the operational results are quite good. For the scrubber tower in the pressurized gasification of water-coal slurry, we added more tray levels, resulting in a fairly satisfactory purification effect.
An empty tower is also fine; as long as the right nozzle is used, the results will be good
What is the liquid-to-gas ratio in a typical scrubber tower? What is the gas velocity?
An empty tower with appropriate nozzles is a good choice. Because the clog-resistant performance and particle size of nozzles have seen significant improvements nowadays, the cleaning efficiency has been greatly enhanced!
First, it is necessary to determine the flow rate of the scrubber tower, which can be determined based on the gas flow velocity (3-5 m/s). Of course, some are better, (1.8-2.5 m/s). For a given scrubber tower, the liquid flow rate is determined based on the diameter of the tower; it is generally not less than 15 tons/(square meter·hour).
The factory over there uses an evaporative hot water tower. Could you please explain in detail its structure and principle? Thank you
Well said, it’s just not explained clearly
In coal-to-methanol projects, the syngas washing tower is equipped in such a way that the crude syngas first undergoes rough dust removal through a downward bend at the bottom of the tower, where it comes into contact with gray water； It is then washed with process condensate through three layers of trays; it is advisable to use buffer baffle trays to prevent fine ash from causing blockages, as bubble or floating valves are prone to getting clogged ； If further dust removal is required, a swirl plate demister can be used; its pressure drop is low, generally below 300 Pa, and it provides good results ； To remove entrained droplets, a vertical defoamer can be installed at the top; it is generally capable of removing only droplets as small as 50 microns, but it has much better anti-clogging performance than a mesh defoamer.
Our company uses packed towers! There is too much dust; it’s inevitable to clean the tower regularly! :(
I think rephrasing the question might make it clearer: What is the appropriate choice for a scrubber tower in the dry coal powder gasification waste boiler process? Selection of scrubber tower for dry coal powder gasification quenching process? Selection of scrubber tower for water-coal slurry gasification quenching process? In my opinion, this is because of the differences in their gas composition; particularly in the cases of quenching and spent boiler processes, the moisture content of the gas varies significantly. If the ash content is high, using a packed tower may lead to blockages easily. It’s just my personal opinion; I hope everyone can give me some guidance.
We’re still using rigid mesh packed towers even now that we’re behind