MODELING OF TWO-FLOW GAS PURIFICATION FROM CARBON MONOXIDE (IV) BY MONOETHANOLAMINE SOLUTION

Abstract

A two-flow scheme for gas purification from CO2 by monoethanolamine (MEA) solution and by waste solution regeneration in two simultaneous recuperators is the object of the simulation, the productivity of ammonia is 1360 tons/day. Our algorithm takes into account the temperature fluctua-tions, component concentrations in gas and liquid phases at different points of the absorber. The algorithm is implemented in Excel environment. The peculiarity of the calculation consists in the selection of CO2 concentration in the gas after "rough" purification to obtain approximately equal flows of finely and roughly recovered solutions in the absorber. For kinetic calculation of the absorber, the reference dependences of the equilibrium partial pressure of CO2 over the MEA solution are approximated, depending on the degree of carbonization, the temperature and CO2 concentration in the solution. The number of plates in two-section plate absorber is calculated by numerical integration. The control calculation is performed with the following initial data. The consumption of con-verted gas supplied for purification is 206000 m3/hour. The MEA temperature at the inlet is 313 K. The concentration of the MEA at the inlet of the absorber – 20 % by mass. The final concentration of CO2 is 0.01 %. The pressure in the absorber – 2.8 MPa. The concentration of the components in the dry gas mixture, % vol.: CO2 – 17.36; CO – 0.5; H2 – 61.64; CH4 – 0.3; N2 – 19.95; Ar – 0.25. The concentration of CO2 at the outlet, % vol.: after "rough" purification was unknown and is selected by multivariate calculation 5.64; after "fine" purification is 0.01. This algorithm can be used to analyze the performance of existing plants, and will also be useful for students' learning the design of process gas purification schemes.