The CO2 content in the carbon propene decarboxylation vapor is low
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In our plant, the operation pressure for carbon propene decarboxylation is 1.8 MPa; the pressure at the first stage of flash evaporation is 0.8 MPa, and that at the second stage is 0.38 MPa. The inlet CO2 concentration is 26%, while the outlet CO2 concentration is 0.6% (in a co-alkolization unit, this value can reach 0.1%). The CO2 concentration after the first stage of flash evaporation is 30–40%, whereas it is around 60% after the second stage. I inspected a plant with an operating pressure of 1.85 MPa; it had only one stage of flash evaporation, with the pressure controlled at 0.38 MPa, and the CO2 concentration was around 70%. I would like to ask everyone what factors could be causing our flash vapor CO2 level to be low.
It’s completely normal; the primary flash pressure is 0.8 MPa, and most of the carbon dioxide remains in the solution, so the concentration of the vapor produced by flashing is low. This is also a requirement for recovery.
It’s completely normal; it’s also a requirement for recycling. :P
Mainly, the pressure in the first stage of flash evaporation is too high. Our pressure for the first stage of flash evaporation is 0.75 MPa, at which point CO2 concentration can reach 66%; the pressure in the second stage of flash evaporation is below 0.5 MPa, allowing CO2 concentration to reach 93%
The purpose of the PC decarburization flashing process is to remove the small amount of inert gases (H2, N2, CH4, etc.) dissolved in the PC liquid, so as not to affect the purity of the final CO2 product gas. The operating pressure of the flash vaporization system is an important factor affecting whether the flash vaporization process operates properly; the control parameters are generally as mentioned by those above. Another important factor is the impact of the circulation volume of the PC fluid. According to the data provided by the poster, the CO2 concentration in the gas after decarbonization reaches 0.6%, indicating an excellent decarbonization effect (the general design target is