Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
A novel solar-driven system for two-step conversion of CO2 with ceria-based catalysts
KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Global warming is an unequivocal fact proved by the persistent rise of the average temperature of the earth. IPCC reported that scientists were more than 90 % certain that most of the global warming was caused by increasing concentrations of greenhouse gases (GHG) produced by human activities. One alternative to combat the GHG is to explore technologies for utilizing CO2 already generated by current energy systems and develop methods to convert CO2 into useful combustible gases.

Two-step conversion of CO2 with catalysts is one of the most promising methods. Ceria (CeO2) is chosen as the main catalyst for this conversion in the thesis. It releases O2 when it is reduced in a heating process, and then absorbs O2 from CO2 to produce CO when it is re-oxidized in a cooling process.

To make the conversion economic, solar power is employed to drive the conversion system. In this thesis, a flexible system with fluidized bed reactors (FBRs) is introduced.

The thermogravimetric analysis (TGA) was carried out to examine the performance of ceria during its reduction and oxidation. Subsequently, the exergy analysis was used to evaluate the system’s capability on exporting work. The theoretical fuel to chemical efficiency varied from 4.85 % to 43.2 % for CO2 conversions.

To investigate the operation mechanism of the system, a mathematical model was built up for the dynamic simulation of the system. Variables such as temperatures and efficiencies were calculated and recorded for different cases. The optimum working condition was found out to be at 1300 ⁰C for the commercial type of ceria.

Finally, an experimental system was set up. The hydrodynamics and heat transfer in the fluidized bed reactor were studied. A CFD model was built up and validated with the experimental trials around 120 ⁰C. The model was then used as a reliable tool for the optimization of the reactor.

The entire work in the thesis follows the procedure of developing an engineering system. It forms a solid basis for further improvements of the system to recycle CO2.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. , xxv, 159 p.
Series
TRITA-KRV, ISSN 1100-7990 ; 14:05
Keyword [en]
CO2 conversion, solar, ceria, thermogravimetric test, exergy analysis, simulink, fluidized bed, gas-solid flow, simulation
National Category
Energy Engineering
Research subject
Energy Technology
Identifiers
URN: urn:nbn:se:kth:diva-152899ISBN: 978-91-7595-285-7 (print)OAI: oai:DiVA.org:kth-152899DiVA: diva2:751958
Public defence
2014-10-24, Sal M235 (Learning Theatre), Brinellvägen 68, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20141006

Available from: 2014-10-06 Created: 2014-10-02 Last updated: 2014-10-06Bibliographically approved
List of papers
1. The design of a solar-driven catalytic reactor for CO2 conversions
Open this publication in new window or tab >>The design of a solar-driven catalytic reactor for CO2 conversions
Show others...
2014 (English)In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 57, 2752-2761 p.Article in journal (Refereed) Published
Abstract [en]

The solar energy has been employed to provide the heat for CO2 conversions for several years except for its use on power generation, since it is one of the most common renewable energy resources and the total amount is enormous; However, the dominant method is to concentrate solar rays directly on reactants, relying on the design and quality of the receivers a lot. The operation and maintenance of the receivers require extra attention due to the delicate structure of the receivers and the potential contamination on the lenses from the chemical reactions. To steer clear of the shortcoming, a solar-driven catalytic reactor has been designed and analyzed in this article. The reactor drives the endothermic reactions with the heat source of hot gases, which are produced in solar receivers upriver, thus the flexible and necessary operations on the catalytic reactor could be peeled off from the solar receiver, and the potential contamination on the optical components in the solar receiver could be avoided. The design processes and details are described, the heat performance is simulated and analyzed, and efficiencies are theoretically calculated in this article. The solar-driven catalytic reactor exhibits the possibility of the practical use of solar energy in CO2 conversion and recycle.

National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-153644 (URN)10.1016/j.egypro.2014.10.307 (DOI)000348253202095 ()2-s2.0-84921990102 (Scopus ID)
Note

Updtated from accepted to published.

Available from: 2014-10-06 Created: 2014-10-06 Last updated: 2017-12-05Bibliographically approved
2. Review on the two-step-conversion of CO2 driven by solar energy
Open this publication in new window or tab >>Review on the two-step-conversion of CO2 driven by solar energy
2013 (English)In: The Journal of Macro Trends in Energy and Sustainability, ISSN 2333-0511, Vol. 1, no 1Article in journal (Refereed) Published
Abstract [en]

The catalytic conversions of CO2 and H2O emerge as an attractive way to recycle CO2 and H2O to provide synthesis gas as an alternative fuel. Two-step-conversion method with catalysts shows a better performance among different techniques for converting CO2. Solar energy is highly interesting for researchers since it is renewable, feasible and abundant. This article reviews the different aspects of two-step-conversion of CO2 driven by solar energy, including the catalysts used for conversions, and the conversion systems with solar energy. The article focuses on ceria (CeO2) as the promising catalyst, and the looping circulating fluidized bed as the reactors for conversion systems with the prospect. The factors affecting the gas-solid interaction in fluidization are also reviewed. As the conclusion, the two-step conversion of CO2 driven by solar energy appears competitive and ceria gets advantages among the involved catalysts.

Keyword
Thermochemical, Two - step, CO2 conversion, Solar energy, Fluidization, Ceria
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-153641 (URN)
Note

QC 20141006

Available from: 2014-10-06 Created: 2014-10-06 Last updated: 2017-01-13Bibliographically approved
3. Catalytic CO2 conversion via solar-driven fluidized bed reactors
Open this publication in new window or tab >>Catalytic CO2 conversion via solar-driven fluidized bed reactors
2014 (English)In: International Journal of Low-Carbon Technologies, ISSN 1748-1317, E-ISSN 1748-1325, Vol. 9, no 2, 127-134 p.Article in journal (Refereed) Published
Abstract [en]

Converting CO2 and steam (H2O) into synthesis gas is a new route to recycle them to fuels. Conversions are performed via a two-step conversion method in which catalysts are heated up and cooled down repeatedly with CO and H2 as the products. To make the method economic, solar energy is employed to drive conversion systems. A solar-driven system with fluidized bed reactors is proposed for CO2 conversion in this paper, and numerical models are built to study its performance and find out the optimum working condition. The investigation proves that system is a competent candidate to power the two-step conversion of CO2 for the carbon recycle and the syngas production.

Keyword
Chemical reactors; Fluid catalytic cracking; Fluidized bed furnaces; Numerical models; Recycling; Solar energy; Synthesis gas, Conversion methods; Conversion systems; Fluidized bed reactors; Optimum working conditions; Syngas production; System assessment, Carbon dioxide
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-153633 (URN)10.1093/ijlct/ctu018 (DOI)2-s2.0-84900528895 (Scopus ID)
Note

QC 20141006

Available from: 2014-10-06 Created: 2014-10-06 Last updated: 2017-12-05Bibliographically approved
4. The thermodynamic analysis of two-step conversions of CO2/H2O for syngas production by ceria
Open this publication in new window or tab >>The thermodynamic analysis of two-step conversions of CO2/H2O for syngas production by ceria
2014 (English)In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 39, no 23, 12353-12360 p.Article in journal (Refereed) Published
Abstract [en]

Due to the challenges of demands on alternative fuels and CO2 emission, the conversion of CO2 has become a hot spot. Among various methods, two-step conversion of CO2 with catalyst ceria (cerium oxide, CeO2) appears to be a promising way. Solar energy is commonly employed to drive the conversion systems. This article proposes a solar-driven system with fluidized bed reactors (PER) for CO2/H2O conversions. N-2 is used as the gas of the heat carrier. The products of CO/H-2 could be further used for syngas. To evaluate the capability of the system for exporting work, the system was analysed on the basis of the Second Law of Thermodynamics and the reaction mechanism of ceria. Heat transfer barriers in practical situations were considered. The lowest solar to chemical efficiency is 4.86% for CO2 conversion, and can be enhanced to 43.2% by recuperating waste heat, raising the N-2 temperature, and increasing the concentration ratio. The analysis shows that the method is a promising approach for CO2/H2O conversion to produce syngas as an alternative fuel.

Keyword
Thermodynamic analysis, CO2 conversion, CeO2, Solar energy, Syngas
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-150930 (URN)10.1016/j.ijhydene.2014.03.250 (DOI)000340328800059 ()2-s2.0-84904727862 (Scopus ID)
Note

QC 20140912

Available from: 2014-09-12 Created: 2014-09-11 Last updated: 2017-12-05Bibliographically approved
5. The numerical and experimental study of a fluidized bed reactor for the two-step conversion of CO2
Open this publication in new window or tab >>The numerical and experimental study of a fluidized bed reactor for the two-step conversion of CO2
(English)Manuscript (preprint) (Other academic)
Identifiers
urn:nbn:se:kth:diva-153652 (URN)
Note

QS 2014

Available from: 2014-10-06 Created: 2014-10-06 Last updated: 2014-10-06Bibliographically approved

Open Access in DiVA

Thesis(4055 kB)455 downloads
File information
File name FULLTEXT01.pdfFile size 4055 kBChecksum SHA-512
4a26910f24afd7f37867b8d0a88657c58c31b6dac27aa84ef9d6df7705146e929909c70b0341dc9a659822aa4f9d820f5eefa5fe971616b86d7d2dc12696358f
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Wei, Bo
By organisation
Heat and Power Technology
Energy Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 455 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 277 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf