Carbon dioxide in the purified gas

Your regeneration system does not carry out regeneration thoroughly, resulting in a low heat load on the tower; this leads to incomplete regeneration of lean methanol, which directly affects the mass transfer process, diminishes the absorption efficiency, and causes the composition levels to exceed acceptable limits.

An excessive circulation rate of methanol leads to incomplete separation, resulting in insufficient cooling capacity; this exacerbates the problems within the system and causes the carbon dioxide level in the purified gas to exceed the allowable limits

The flow rate of methanol in the bypass circuit of the scrubber can be increased

Why does increasing the circulation rate actually hinder resolution? I look forward to your advice! 3# zxs

Check the water content! Either something has leaked somewhere.

In addition to the reasons you mentioned, the reasons for the excessive level of sulfur dioxide in the purified gas include the following: 1. The temperature of the absorbent is higher than the designed value. 2. The absorbent is not regenerated thoroughly. 3. The efficiency of the tray plates is low; this may be due to flooding in the tower or blockages in the tray plates, which affect efficiency. 4. It could also be due to a high gas-phase load and high flow rates, resulting in local short circuits in the tray plates. 5. There are issues with the instruments; important temperature and flow meters may be giving incorrect readings

This post was last edited by eddy-8280103 on 2009-9-7 at 16:17. I agree with the comments above; the main reasons for the high CO2 level are indeed these factors. You should check whether there are any problems in these aspects related to your equipment. If it’s caused by other factors, please let us know what they are so that we can be more careful in our future work. Thank you.

Based on what you’ve described, the following reasons are analyzed for your reference: Is the water content in the system too high? Is the heat load of the regeneration tower too low? CO2 in the lean methanol is stripped in the absorption tower. Is there internal leakage in the inlet heat exchanger of the methanol washing unit?

Reasons for the excessive carbon dioxide content in the purified gas: ① The gas-liquid ratio in the decarboxylation tower is too high, that is, the flow rate of the solvent entering the decarboxylation tower is low. ②The temperature of the carbon propylene liquid entering the decarburization tower is high. ③The carbon propylene liquid entering the decarburization tower has a high carbon dioxide content. ④The carbopropyl liquid has been diluted, resulting in a low concentration. ⑤The pressure in the decarbonization tower is low. ⑥The packing in the decarbonization tower is clogged, resulting in uneven flow of gas and liquid and poor contact. ⑦The production load is too high, resulting in overloading. The recommended treatment method is ① to appropriately increase the carbon propylene flow rate into and out of the decarburization tower, thereby reducing the gas-liquid ratio inside the tower. ②Increase the cooling water flow rate in the propylene carbon cooler, or use cooling water at a lower temperature, to improve the cooling effect and reduce the temperature of the propylene carbon liquid in the carbonation and decarboxylation towers. If the cooler is clogged due to scaling, it should be shut down for cleaning. ③Take appropriate measures to reduce the carbon dioxide content in the lean liquid and increase the leanness of the carbon-propane mixture entering the decarboxylation tower. ④When the concentration of the propylene carbonate solution is low, reduce the water content in it while preventing the solution from being diluted. ⑤The decarbonization pressure is kept within the specified limits.