Study On Absorption Of Carbon Dioxide Using Organic Amines

Activated methyldiethannolamine（MDEA） solution is thought asone of the most application for CO₂removal process in synetheticammonia industry. The advantages of this method are higher capacityfor CO₂absorption, lower regeneration energy cost, lower erosion toequipment. In this paper, organic amines absorption CO₂is studied in apacked tower during circulation process of absorption and desorptionand effect of various factors are also discussed.First, CO₂concentration of tail gas, absorption rate of CO₂,capacity of CO₂absorption and solution recovery ratio of CO₂arestudied about a MDEA aqueous solution blend with piperazine（PZ） andits homologous compounds（HEPZ, AEP）. Results show that activation ofaddition absorbents obey the following rule: AEP> PZ> HEPZ, andamino group is more important than hydroxyl group during CO₂absorption process.This paper also analyzes the relation between gas/liquid rate andabsorption effect of a MDEA aqueous solution blend with AEP. It findsthat CO₂concentration of tail gas increase with growing gas rate anddecrease with liquid rate. What’s more, absorption rate of CO₂aboutthis solution has been discussed. Absorption rate decrease with time,and obey following equation: y=kexp（-x/t0）+y0. Analyze therelationships between concentration of activator and equationparameters, we can get following equation: N=f（t,c,c’）, absorption ratechange with time, concentration of activator and kinds of activator.Besides, a TEA aqueous solution blend with AEP or TEPA is studied.And it concludes that TEPA is better than AEP. Temperature ofdesorption about a TEA aqueous solution blend with TEPA solution hasstudied. During the temperature （105℃,115℃,125℃）, the best desorption temperature is115℃. Single absorbent （MDEA, TEA, AMP） forCO₂capture is tested for1mol/L, and the activation obeys thefollowing rule: AMP>MDEA>TEA.Finally, ternary amine blend solution （MDEA, AMP, PZ） is studied,when total amine concentration is1mol/L and AMP concentration is0.05mol/L, CO₂concentration of tail gas decrease with adding PZ. Thispaper concludes that when treating two activators as an entirety wecan get the same regulation as binary amine blend solution. In this point,we study solution （MDEA+AMP+PZ, MDEA+AMP, MDEA+PZ） under thesame concentration of activators, the results show that MDEA+AMP+PZis better than MDEA+AMP or MDEA+PZ.