275765 Heat Integrated Moving Bed Adsorption Process for Carbon Dioxide Capture

Tuesday, October 30, 2012
Hall B (Convention Center )
Yongho Son, Kiwoong Kim, Daewook Kim and Kwang Soon Lee, Chemical and Biomolecular Engineering, Sogang Univ., Seoul, South Korea

Heat integrated moving bed adsorption process for carbon dioxide capture

Yongho Son, Kiwoong Kim, Daewook Kim, and Kwang Soon Lee*

Sogang university, South korea

 (kslee@sogang.ac.kr)

A heat integrated moving bed adsorption (MBA) process is proposed as a potentially viable CO2 capture process from large scale CO2 emitting plants. The proposed process depicted in Figure 1 consists of an adsorption bed and two desorption beds through which the adsorbent particles are continuously circulated. The adsorption bed is run under a low temperature and 1 atm while the adsorbent and gas flow in opposite directions. The adsorbent particles discharged from the adsorption bed are carried to a desorption bed under a high temperature and 1 atm, and transferred to another desorption bed under a high temperature and a vacuum, and returned to the adsorption bed. Heat integration is designed to maximally recover the heat of adsorption from the adsorption bed to supply the heat of desorption required in the desorption beds.

Fig. 1. The schematic diagram of MBA process.

The unsteady-state numerical model of the MBA process has been developed. The governing partial differential equation (PDE) model was set up from the mass and energy balances for the gas and solid phases and the associated constitutive equations. Then, an ordinary differential equation (ODE) model in time was derived by applying a collocation technique along the spatial coordinate. The process behavior with the variation of manipulable variables has been shown.

Afterward, the economy as a CO2 capture process from a large CO2 source was assessed. Economy evaluation using a numerical model was carried out in comparison with other existing techniques. Process optimization and economy evaluation was performed for the case that zeolite 13X is used as the adsorbent.

The lower bounds of the optimization were set as 65% recovery and 99.5% purity of CO2. The MBA process at optimum operating conditions exhibits the cost reduction of about 52% compared to the conventional MEA-absorption process by Fluor Daniel Co.

The MBA process is proposed only conceptually but reveals a great potential as a novel process that can replace the existing CO2 capture processes. In addition, the process idea may be transferred to solid-phase absorption processes and enhance the economic feasibility greatly.

Table 1. Economy analysis of the MBA process and the MEA absorption process.

Steam

($4.40/ton)

Electric power

($0.07/kWh)

CW, 11 ($0.0045/m3)

Etc.

Subtotal w/o SOX, H2O removal ($/ton)

MEA process [1]

7.90

2.77

0.34

2.66 (Added

chemicals)

13.67

MBA process

3.88

2.13

0.05

0.22 (Adsorbents

transport)

6.28

[1] D.G. Chapel, C.L. Mariz, and J. Ernest. Recovery of Co2 from flue gases: commercial trends, (1990), Aliso Viejo


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