초록 ▼

2. 개발내용 및 결과
- 기초 실험장치를 이용한 분리막 성능평가 : 연소전 CO₂ 포집용으로 개발 된 분리막 및 성능 비교평가를 위한 상용 A사 분리막 모듈에 대하여 기초실험을 수행하였으며, 이를 이용하여 포집공정 설계자료로 활용하였음
- 연소전 CO₂ 포집을 위한 수성가스전이반응 단위공정 개발 : 합성가스를 CO₂와 H₂로 전환하기 위한 수성가스전이반응(WGS)은 HTS와 LTS로 구성함. 조업조건으로 압력 1-20기압, S/C 비 2.5-

2. 개발내용 및 결과
- 기초 실험장치를 이용한 분리막 성능평가 : 연소전 CO₂ 포집용으로 개발 된 분리막 및 성능 비교평가를 위한 상용 A사 분리막 모듈에 대하여 기초실험을 수행하였으며, 이를 이용하여 포집공정 설계자료로 활용하였음
- 연소전 CO₂ 포집을 위한 수성가스전이반응 단위공정 개발 : 합성가스를 CO₂와 H₂로 전환하기 위한 수성가스전이반응(WGS)은 HTS와 LTS로 구성함. 조업조건으로 압력 1-20기압, S/C 비 2.5-5, HTS 온도는 350-400℃, LTS 온도는 180-230℃ 일 때, LTS 후단의 가스조성은 H₂ 57-60%, CO₂ 36-42%, CO는 1% 미만을 얻음
- 실험실규모 연소전 CO₂ 포집 공정 개발(2L/min) : 석탄가스화 시스템에 연계할 수 있는 WGS와 분리막 공정으로 구성된 시스템을 ASPEN과 Fluent를 이용하여 설계하고 제작 및 시운전하고, 공정 실험은 개발 분리막과 A사 분리막 모듈을 이용하여 운전함. 연소전 포집실험결과, 압력 15기압, 분리막단위면적당 유량이 60cc/min.cm² 조건에서 CO₂ 포집가스(retentate) 조성은 CO:H₂:CO₂ = 2.0:7.6:90.4%로 CO₂를 90%이상 포집할 수 있음. A사는 10기압, 분리막단위면적당유량이 26cc/min.cm² 조건에서 permeate 조성은 CO:H₂:CO₂ = 1.0:35.7:63:3%의 성능을 보임
- 벤치규모 연소전 CO₂ 포집 공정 개발(1Nm³/hr) : 실험실규모 공정실험 결과를 이용하여 벤치규모 공정 설계, 제작 및 시운전 함. WGS와 다층분리막을 연계한 벤치규모 연소전 공정으로, 최적조건에 서 실험결과로 WGS 후단 조성은 CO:H₂:CO₂ = 0.76:59.45:39.79%, 분리막 공정 조건은 20기압, 400℃에서 CO₂ 포집가스 조성은 CO:H₂:CO₂ = 1.2:8.0:90.6%로 CO₂를 90%이상 포집할 수 있음
- 석탄가스화 연계 연소전 CO₂ 포집 격상공정 설계 : 벤치규모 포집공정 실험결과와 공정 해석 툴을 이용하여 1ton-coal/day급 석탄가스화 시스템에 연계한 CO₂ 포집 격상공정 기본 설계 자료 확보
- 반응분리 동시공정 기반 기술 개발 : 촉매를 이용한 수성가스전이반응과 분리막을 이용한 CO₂ 포집을 동시에 할 수 있는 반응분리 공정 실험결과, 130% 이상의 CO 전환율을 얻음

Abstract ▼

The importance of developing CO₂ capture and storage(CCS) technologies is increasing rapidly as it is closely related with preventing climate change by global warming. Among various CCS technologies, pre-combustion CO₂ capture process using membranes are regarded as a next-gene

The importance of developing CO₂ capture and storage(CCS) technologies is increasing rapidly as it is closely related with preventing climate change by global warming. Among various CCS technologies, pre-combustion CO₂ capture process using membranes are regarded as a next-generation capture process due to its effectiveness and economic feasibility, and R&D for pre-combustion CO₂ capture with membrane is lively on the way in many advanced countries.
In this study, a core process for pre-combustion CO₂ capture has been developed using water-gas shift reactors and dense hydrogen transport membranes. For the past three years of this project, tests for membranes, developing lab-scale and bench-scale process, and design for upgrading system have been performed, and test for reaction/separation process is also proceeded.
An efficiency analysis of developed membranes which is used for pre-combustion CO₂ capture is performed, and its results are used for the background data of design of overall CO₂ capture process. In addition, to set up the development direction, compared evaluation of Pd-Cu membrane and commercial membranes from A company(A membrane) is carried out.
Water-gas shift(WGS) unit process for converting syngas to CO₂ and H₂ is developed, and it is composed of HTS and LTS. Gas compositions of the rear site of LTS were given by H₂=57-60%, CO₂=36-42%, and CO=under 1% at operation conditions of pressure=1-20bar, S/C ratio=2.5-5, temperature of HTS=350-400℃, and temperature of LTS=180-230℃.
To develop the lab-scale pre-combustion CO₂ capture process(2L/min), WGS and membrane process-combined system for integrating coal gasification process was designed, manufactured using ASPEN and Fluent and operated using Pd-Cu membrane module and A membrane module. Pre-combustion CO₂ capture test results showed that the composition of CO₂ captured gas(retentate) was CO:H₂:CO₂ = 2.0:7.6:90.4vol% at conditions of pressure=15bar and flow rate per unit membrane area=60cc/min·cm², and it achieved over 90% of CO₂ concentration. In case of A membrane, it showed the retentate gas composition as CO:H₂:CO₂ = 1.0:35.7:63.3vol% at condtions of pressure=10bar and flow rate per unit membrane area=26cc/min·cm².
For the purpose of developing bench scale pre-combustion CO₂ capture process(1Nm³/hr), lab-scale experimental results were used for designing, manufacturing and operating of bench-scale process. The optimum results of bench-scale pre-combustion process composed of WGS and multi-layer membrane module showed that the composition of CO₂ captured gas(retentate) was CO:H₂:CO₂ = 1.2:8.8:90.6vol% at operation conditions of pressure=20bar, temperature=200℃, composition of gas stream from WGS as CO:H₂:CO₂ = 0.8:59.5:39.7vol%. This experimental result also obtained over 90% of CO₂ concentration. As using experimental results from bench-scale process and process interpretation tools, fundamental design data of advanced CO₂ capture process which is integrated with 1 ton-coal/day scale coal gasification is attained. In addition, after development of consecutive reaction/separation process-based technology that performs WGS reaction through catalysts and CO₂ capture using membranes at the same time, over 130% of CO conversion rate is achieved.
In conclusion, in this project, bench-scale pre-combustion CO₂ capture process(1Nm³/hr) has been developed, and its performance proved to show over 90% of CO₂ recovery at the conditions of temperature=400℃ and pressure=20bar. In the next step of this project, coal gasification system integrated pre-combustion CO₂ capture process will be developed.