Design is the key step for the commercial process of post combustion CO2 capture by using the amines based solvents. Also, the simulation of the CO2 capture process could provide the guideline or more information for the design. The improvement or enhancement of the process configuration could be achieved by using the simulation. This chapter consists of two main sections. One is the methods for determination of column height for CO2 absorber. The procedure for column design are present in order to get the final destination of column height. Four different method are discussed in this part. Another is about the developed process configurations for post combustion CO2 capture. In this part, the present development for the process improvement of post combustion CO2 capture are discussed in terms of absorber, stripper, and economizer modification. All detailed development are shown in this chapter in order to give the clear picture of the process configurations development for post combustion CO2 capture.

Design, Modeling and Simulation of Post Combustion CO2 Capture Systems Using Reactive Solvents

The influence of suspended fine particles of differing adsorbing capacity (activated carbon, avicell cellulose, SiO2, and molecular sieves) on the liquid-film mass transfer coefficient κL, was examined experimentally in a stirred cell of well-defined gas-liquid interfacial area by chemical methods. The greatest effect on κL was observed with the activated carbon (about a threefold increase). An addition of glycerine in excess of 2.5 × 10−3 k mol/m3, which was adsorbed on the particles preferentially, removed this increase in κL totally. Amongst other particles, only avicell cellulose showed measureable effects. The increase in κL values was inversely proportional to the temperature and the stirring speed, and the particle loading was found to be immaterial after a certain value. When the reaction rate increased (hence, when the thickness of dissolved gas-rich layer decreased) by gradual addition of a homogeneous catalyst (i.e. Co++ for sulphite oxidation), the effect of particles on κL decreased and event...

Effect of fine solid particles on gas−liquid mass transfer rate in a slurry reactor

A new procedure, called the Novel Pilot Plant Technique (NPPT), for designing gas absorbers with chemical reactions is proposed. The technique is based on the premise that full-scale absorption columns can be sized by making a minimum number of tests using small-scale pilot plants. Two special features of the technique are that (i) detailed design parameters (such as mass transfer coefficients, reaction kinetics, physical properties) need not be known and (ii) complex calculations are avoided. The validity of the technique is demonstrated for the CO2-NaOH system, for which the absorber height can be calculated accurately from first principles.



Une nouvelle methode est proposee, appelee «Novel Pilot Plant Technique» (NPPT), pour mettre au point des colonnes d'absorption gazeuse en presence de reactions chimiques. La technique s'appuie sur l'hypothese qu'on peut determiner les dimensions des colonnes d'absorption en pleine grandeur avec un minimum d'essais grǎce a des installations pilotes de petite echelle. Cette technique possede deux caracteristiques, a savoir que les parametres de conception detaillee (tels que les coefficients de transfert de matiere, la cinetique de reaction, les proprietes physiques) doivent ětre connus, et que les calculs complexes sont evites. La validite de la technique est demontre pour le systeme CO2-NaOH, pour lequel la hauteur de la colonne d'absorption peut ětre calculee avec exactitude a partir de ces premiers principes.

Novel pilot plant technique for sizing gas absorbers with chemical reactions

Triphase catalysis: a new rotating disk contactor for measuring mass transfer coefficients

Equipment which is used in contacting a gas with a reactive liquid can be gas absorber or a gas-liquid reactor. This terminology itself shows the interdisciplinary nature of the process which involves both chemical (i.e. reaction kinetics) and physical (molecular diffusion, fluid mechanics etc.) phenomena. Thus the subject does not fall entirely within the province of either the chemist or the conventional engineer. The classical literature on this area (Astarita (1), Danckwerts (2), Sherwood et al. (3) etc.) has mainly dealt with gas absorption, in which the reaction is applied merely to enhance the rate of mass transfer. In such cases, there is also always a physical gas absorption process to refer to and the reactions are usually “fast”. On the other hand, many industrial reactions in organic chemistry such as oxidations and chlorinations (4), are relatively slow and the main emphasis is the conversion of the liquid phase product. Therefore, two approaches may be used to characterize the interaction of mass transfer and chemical reaction between components of a gas and a liquid, one expressing the enhancement effect of a relatively fast reaction on the physical mass transfer leading to the classical concept of the “enhancement factor” (1–3) and a second, a relatively new one, expressing of slowing down of the already slow reaction rate by mass transfer and leading to the “Utilization factor” (5,6).

Process Design Aspects of Gas Absorbers

A stirred cell has been used as a model of a “point” in a packed column in which gas absorption is accompanied by reaction in the liquid. Values of k L and k G could be varied independently, and were in the range of industrial interest. Using data from the stirred cell, it was possible to predict the height of a packed column for a specified duty to within 9%. The system used was air-C0 2 -NaOH-Na 2 C0 3 .

E. Alper

Papers

Design of gas absorbers: part iii—laboratory “point” model of a packed column absorber