After the low-temperature methanol washing system is shut down (with the circulation still running), can the exhaust gases be directly fed into the exhaust gas scrubber?
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After the low-temperature methanol washing system is shut down (with the circulation still running), since there is no purified gas to exchange heat with the exhaust gases, the temperature of these exhaust gases remains relatively low (around -40 degrees). Could freezing occur inside the exhaust gas scrubber if the gases enter it directly, thereby causing damage to the equipment? Because the flow rate of the exhaust gas is high and its temperature is low, if it enters the exhaust gas scrubber directly, the amount of desalinated water sprayed from the top of the tower is very small; upon coming into contact with the exhaust gas, its temperature drops rapidly. We are concerned that it might drop to the freezing point of water, causing ice formation that could block the scrubber or damage the equipment I’m not sure if this concern is valid; let’s discuss it? ? For this reason, the exhaust gas is vented through the bypass valve of the exhaust gas scrubber without passing through the absorption tower; however, in this way, the hydrogen sulfide concentration tower cannot maintain its pressure I feel conflicted and don’t know what’s the right way to handle it! ! We are using the low-temperature methanol washing process package from Dalian University of Technology, a six-tower process! !
We use the LURGI process; to avoid the phenomenon described by the original poster, the exhaust gas entering the scrubber tower is supplied with low-pressure steam via control valves, to ensure that freezing does not occur inside the tower. Additionally, steam is introduced into the tower through on-site shut-off valves as well, to prevent freezing! Once ice forms inside the tower, the scrubber tower is also equipped with a U-shaped water seal bypass; when the resistance in the scrubber tower increases, the exhaust gases are vented through this bypass!
What you said is very insightful. However, could you send me the flowchart you have for the exhaust gas scrubber? That would help me understand it better through the diagrams. Thank you! ! Please send the drawings to: yichaoshan2005@163.com
The exhaust gases contain methanol, and methanol can lower the freezing point of water. If the methanol content in the exhaust gases is high, can this prevent freezing?
Generally, there is a steam heater before entering the exhaust gas absorption tower, which is also designed to prevent cold air from escaping. As the original poster said, there is no gas supply and only recirculation is in use; as a result, the amount of vapor generated is very small.
The issue raised by the original poster is indeed one that wasn’t taken into account in Dalian University of Technology’s process package; this steam flow needs to be included.
May I ask everyone, if we want to add this steam, where should it be added? Our exhaust pipeline is DN800 in diameter; what diameter steam pipeline would be appropriate to use? !
Our 32-inch vent pipe is equipped with 2-inch low-pressure steam at 0.6 MPA!
Don’t we have the steam mentioned above? ? “The exhaust gas is vented through the bypass valve of the exhaust gas scrubber without passing through the absorption tower, but in this way can the hydrogen sulfide concentration tower not maintain its pressure? ”That won’t happen; we’re currently releasing pressure through a bypass, via a pressure control valve, and the pressure in Tower T3 is quite good.
The original poster explained things very well. We are using a process package and are about to start operation; it’s useful to draw on experience from various sources. Could you provide a contact number?
Is the pressure control valve for your T3 tower located after or before the connection point where the exhaust gas from the T6 tower meets the bypass pipeline? Ours was before; in that case, if the exhaust gases take a detour after the vehicle stops, won’t the pressure in Tower T3 fail to be maintained? Do you mean to add another pressure control valve later? For an exhaust pipeline with a diameter of one meter, installing a pressure control valve will definitely cost a lot. I was thinking – could I use steam instead? What other methods are there? Please keep discussing! !