Chemical-looping combustion and chemical-looping with oxygen uncoupling for CO2 capture, covering oxygen carrier, reaction kinetics, CFD simulation, cold-flow model and hot rig

1. Introduction

Current state-of-the-art carbon capture and storage (CCS) technologies usually have to overcome the problems of high energy penalty and capture cost, therefore, theoretical innovation and technological breakthroughs of CCS are necessary. Chemical looping combustion (CLC), which utilizes circulating solid oxygen carrier particles to transmit active oxygen from air reactor to fuel reactor, is regarded as one of the most promising CCS technologies. CLC exhibits the comprehensive advantage of high energy conversion efficiency, low cost for carbon capture and pollutant control.

2. Research findings
(1) Initiative design and conditioning efficiency of oxygen carrier

Oxygen carrier particles act as a bridge of the active oxygen transfer and energy transfer between the fuel reactor and air reactor. The optimization design and batch preparation of a high-performance oxygen carrier are the key factors for low cost and scaling-up of CLC systems. A lot of oxygen carriers, such as NiO/NiAl2O4, CuO/CuAl2O4, CuFe2O4, copper-decorated hematite and copper ore, etc., upon on initiative design, were developed and examined for oxygen carrier materials of CLC/CLOU and a spouted bed batch granulation method has been developed.

Granular process of batch spouted fluidized bed (left) and relations of copper modified Fe2O3/Al2O3 between oxygen carrier rate and number of recycles (right)

Reference

1. Haibo Zhao*, Liming Liu, Baowen Wang, Di Xu, Linlin Jiang, Chuguang Zheng. Sol-Gel-Derived NiO/NiAl2O4 Oxygen Carriers for Chemical-Looping Combustion by Coal Char. Energy & Fuels, 2008, 22(2): 898-905.
2. Haibo Zhao*, Daofeng Mei, Jinchen Ma, Chuguang Zheng. Comparison of preparation methods for iron-alumina oxygen carrier and its reduction kinetics with hydrogen in chemical looping combustion. Asia-Pacific Journal of Chemical Engineering, 2014, 10.1002/apj.1791
3. Yongliang Zhang, Haibo Zhao*. Insight into CuO-support interaction and oxygen release mechanism of Cu-based materials by density functional theory calculation. 3rd International Conference on Chemical Looping, 9-11September 2014, Chalmers University of Technology, Gothenburg, Sweden. Oral Presentation
4. Baowen Wang, Rong Yan, Haibo Zhao, Ying Zheng, Chuguang Zheng. Investigation of chemical looping combustion of coal with CuFe2O4 oxygen carrier. Energy & Fuels, 2011, 2011, 25 (7), 3344–3354
5. Jinchen Ma, Haibo Zhao*, Lei Guo, Daofeng Mei, Weijin Ynag, Chuguang Zheng. Investigation on batch preparation of iron-based oxygen carrier by spouted bed and using in chemical looping combustion of coal. Journal of Engineering Thermophyscis, 2013, 34(10): 1960-1963

(2) Thermal-chemical characteristic of Chemical Looping Combustion/Chemical Looping with Oxygen Uncoupling Process (CLC/CLOU) with fuel such as coal etc.

Our studies focus on the following several aspects of coal-based CLC/CLOU:

A. Selection of typical oxygen carriers, including NiO/NiAl2O4, Fe2O3/Al2O3, CuO/CuAl2O4, CuFe2O4, natural ores (mainly iron ore and copper ore) and modified ores etc;

B. Reaction characteristics and cycling performance of these oxygen carriers with typical Chinese coals or the production of the coal gasification/pyrolysis;

C. Reaction mechanisms and kinetic behaviors of coal-based CLC/CLOU process.

Chemical reaction characteristicof CuO/CuAl2O4 and natural copper ore coal-based chemical looping oxygen decoupled combustion (left) and oxygen release kinetics of CuO/CuAl2O4 oxygen carrier (right)

Reference

1. Daofeng Mei, Haibo Zhao*, Zhaojun Ma, Chuguang Zheng. Using sol-gel derived CuO/CuAl2O4 oxygen carrier in chemical looping with oxygen uncoupling for three typical coals. Energy & Fuels, 2013, 27 (5): 2723–2731
2. Haibo Zhao*, Kun Wang, Yanfei Fang, Jinchen Ma, Daofeng Mei, Chuguang Zheng. Characterization of Natural Copper Ore as Oxygen Carrier in Chemical-looping with Oxygen Uncoupling of Anthracite. International Journal of Greenhouse Gas Control, 2014, 22: 154-164
3. Kun Wang, Haibo Zhao*. Sulfur behavior in chemical-looping with oxygen uncoupling using a natural copper ore oxygen carrier. 3rd International Conference on Chemical Looping, 9-11 September 2014, Chalmers University of Technology, Gothenburg, Sweden. Oral Presentation
4. Lei Guo, Haibo Zhao*, XixianZou. Synthesis gas generation bychemical-looping autothermal reformingof biomass using Cu-based oxygen carrier. 3rd International Conference on Chemical Looping, 9-11 September 2014, Chalmers University of Technology, Gothenburg, Sweden. Oral Presentation

(3) Design and operation of Interconnected Fluidized Bed reactors for Chemical Looping Combustion

Interconnected fluidized bed reactors (5kWth, 50kWth) were designed and constructed. The fluid dynamic behaviors were investigated in terms of cold-model and hot-model experiemnts and the CFD numerical simulations. Some key factors (Combustion efficiency and CO2 capture efficiency, etc) in CLC/CLOU using different oxygen carriers and different fuels were measured, and suitable operation condition was obtained. The studies offer guidance to the system scaling-up and industrial application.

Cold bench (left) and hot bench (right) of serial fluidized bed

Reference

1. Jincheng Ma, Haibo Zhao*, Xin Tian, Yijie Wei, Yongliang Zhang, Chuguang Zheng. Chemical looping combustion of coal in a 5 kWth interconnected fluidized bed reactor using hematite as oxygen carriers. 3rd International Conference on Chemical Looping, 9-11 September 2014, Chalmers University of Technology, Gothenburg, Sweden. Oral Presentation
2. Jinchen Ma, Haibo Zhao*, Xin Tian, Yijie Wei, Yongliang Zhang, Chuguang Zheng. Continous Operation of Interconnected Fluidized Bed Reactor for Chemical Looping Combustion of CH4 Using Hematite as Oxygen Carriers. 2014 Australia-China Symposium on Energy, May 13-15, 2014, Taiyuan, China. Oral Presentation
3. Jinchen Ma, Haibo Zhao*, Daofeng Mei, Lei Guo, Chuguang Zheng. Cold-flow model experiment of interconnected fluidized bed for chemical looping combustion of coal. Journal of Chinese Society of Power Engineering, 2012, 32(12): 909-915