MODELING OF TWO-FLOW REGENERATION OF MONOETHANOLAMINE SOLUTION

Abstract

The simulation object is a two-flow scheme for gas purification from СО₂ with monoethanolamine (MEA) solution and with waste solution regeneration in two simultaneously-working recuperators, the productivity of ammonia is 1360 tons per day. Our algorithm considers the temperature fluctuations and component concentrations in liquid phases at different points of the desorber. The algorithm of material and thermal balances calculation is implemented in the Excel. The concentration of СО₂ at the outlet of the regenerator is 81.3 %. The specific heat consumption for the regeneration of 1 m³ of СО₂ is 4.02 MJ, which corresponds to industrial data. For kinetic calculation of the desorber, the reference dependences of the equilibrium partial pressure of СО₂ over the 20 % MEA solution are approximated, depending on the degree of carbonization and the temperature in the solution. The number of plates in two-section plate desorber is calculated by numerical integration. The control calculation is performed with the following initial data. Gas temperature – 313 K at the output of the separator; the separator output pressure – 1,7 atm. Gas temperature – 343 K at the output of the regenerator; the regenerator output pressure – 1,7 atm. The carbonization degree of the MEA solution, kmol per kmol MEA: waste solution – 0,67; roughly recovered solution – 0,35; finely recovered solution – 0,1. Temperature, K: on the top plate – 343; output of roughly regenerated solution – 388; output of finely regenerated solution – 398. The plates' quantity calculation gives 33. This algorithm can be used for analyzing productivity of existing plants, and also will be useful for students' learning of the gas purification process in schemes designing.