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
Modeling, simulation and evaluation of biogas upgrading using aqueous choline chloride/urea
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. College of Chemical Engineering, Nanjing Tech University, Nanjing .ORCID iD: 0000-0002-0453-0450
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.ORCID iD: 0000-0002-0200-9960
College of Chemical Engineering, Nanjing Tech University, Nanjing .
Show others and affiliations
2017 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 229, no 1, p. 1269-1283Article in journal (Refereed) Published
Abstract [en]

Biogas has been considered as an alternative renewable energy, and raw biogas needs to be upgraded in order to be used as vehicle fuels or injected into the natural gas grid. In this work, the conceptual process for biogas upgrading using aqueous choline chloride (ChCl)/urea (1:2 on a molar basis) was developed, simulated and evaluated based on the commercialized software Aspen Plus. Reliable thermophysical properties and phase equilibria are prerequisite for carrying out process simulation. In order to carry out the process simulation, the thermophysical properties of ChCl/Urea (1:2) and its aqueous solutions as well as the phase equilibria of gas-ChCl/Urea (1:2), ChCl/Urea (1:2)-H2O and gas-ChCl/Urea (1:2)-H2O were surveyed and evaluated. After evaluation, the consistent experimental data of these thermophysical properties were fitted to the models embedded in Aspen Plus. The properties needed but without available experimental results were predicted theoretically. The Non-Random Two-Liquid model and the Redlich-Kwong equation (NRTL-RK) model were used to describe the phase equilibria. The equilibrium approach was used for process simulation. Sensitivity analysis was conducted to determine the reasonable operating parameters. With a set of reasonable operating conditions, the effects of ChCl/Urea (1:2) content on the total energy utilization, the diameters and pressure drops of absorber and desorber as well as the environmental assessment of the process were studied. The simulation results showed that, with the addition of ChCl/Urea (1:2), the total energy utilization decreased by 16% compared to the process with pure water, and the diameters of both absorber and desorber decreased with increasing content of ChCl/Urea (1:2). The process using aqueous ChCl/Urea (1:2) was more environmentally benign than that with pure water. Therefore, aqueous ChCl/Urea (1:2) is a promising solvent for biogas upgrading.

Place, publisher, year, edition, pages
2017. Vol. 229, no 1, p. 1269-1283
Keywords [en]
Aqueous choline chloride/urea; Thermodynamic modeling; Process simulation; Biogas upgrading
National Category
Energy Engineering
Research subject
Energy Engineering
Identifiers
URN: urn:nbn:se:ltu:diva-63249DOI: 10.1016/j.apenergy.2017.03.059ISI: 000449891500098Scopus ID: 2-s2.0-85018938965OAI: oai:DiVA.org:ltu-63249DiVA, id: diva2:1093199
Note

Validerad;2018;Nivå 2;2018-12-03 (inah)

Available from: 2017-05-05 Created: 2017-05-05 Last updated: 2019-01-15Bibliographically approved
In thesis
1. Development of low-cost ionic liquids (ILs) based technology for CO2 separation
Open this publication in new window or tab >>Development of low-cost ionic liquids (ILs) based technology for CO2 separation
2019 (English)Licentiate thesis, comprehensive summary (Other academic)
Alternative title[sv]
CO2-separation med ny lågkostnads-teknik baserad på Joniska lösningar
Abstract [en]

CO2 capture plays an important role to mitigate CO2 emissions in fossil fuel utilized processes. Meanwhile, CO2 separation is of importance to increase the efficiency of the subsequent product in biomass process, such as biogas upgrading and bio-syngas purification. Among current technologies, the absorption process, i.e. liquid sorbent-based technologies, has received much more attention and been widely studied. Currently, some solvents are available and commercialized for CO2 separation, e.g. amine solutions, Selexol (i.e. dimethyl ethers of polyethylene glycol) and etc. However, it has been reported that these solvents meet some challenges such as high volatility, corrosion, degradation, high cost, and high energy usage for solvent regeneration. Therefore, the development of novel solvents with high capacity and, meanwhile, to overcome the challenges of the currently used or available solvents is essential.

Room temperature ionic liquids (RTILs) show a great potential as alternatives of conventional organic solvents for CO2 separation due to their favorite properties such as high CO2 capacity, non-volatility, high tunability, less corrosion and low energy requirement for solvent regeneration. Therefore, using ILs can be a technology breakthrough for CO2 separation. However, the challenges of using ILs are their high viscosity and preparation cost. To overcome these problems, one way is adding co-solvents to decrease the viscosity, and the other way is to design lowly viscous ILs. In addition, the cost and “green”, i. e. environmental benignity,  are also the concerns when choosing ILs.

The properties of solvents can be used as criteria to select solvents. However, the performance of these solvents in a real process is essential before implementing into the industry but cannot be judged only by properties. Process simulation is a way to design, develop, analyze and optimize the technical process, where the models with approximations and assumptions are used to describe properties over a wide range of temperatures and pressures based on the parameters regressed from real data. Considering that ILs are new and no data or parameters are available in the databank, data determining experimentally, thermodynamic modeling of the data and then process simulating are necessary.

In this thesis, a new type of ILs, i.e. deep eutectic solvent (DES), was selected to study their performance for CO2 separation from biogas. The promising DES investigated here, i.e. choline chloride (ChCl) /Urea with molar ratio 1:2, is “green” and with high CO2 solubility. Considering the high viscosity of this DES, the effect of adding co-solvent (i.e. water) was investigated based on the equilibrium calculation in process simulation. The conclusion from this work suggests that this aqueous ChCl/Urea (1:2) is promising, and the best proportion is around 50% weight percentage of water based on the energy and environmental analysis. After that, the rate-based calculation in process simulation was adopted, and the performance comparison including energy usage and costs for CO2 capture from biogas using aqueous ChCl/Urea (1:2) and commercial organic solvents was carried out. The results show that aqueous ChCl/Urea (1:2) is a better choice and comparable with most commercial solvents except propylene carbonate by energy and economic analyses. Therefore, there is still room to develop new ILs for the enhancement of CO2 separation. Newly prepared morpholinium based ILs were investigated and tested. The one with the highest CO2 capacity was selected, and the preliminary study shows that this novel IL mixed with water has better performance than the solvents that we investigated before, that is, the novel aqueous IL is with lower energy usage and smaller size of equipment. 

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2019
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
National Category
Chemical Engineering Energy Engineering
Research subject
Energy Engineering
Identifiers
urn:nbn:se:ltu:diva-72567 (URN)978-91-7790-300-0 (ISBN)978-91-7790-301-7 (ISBN)
Presentation
2019-04-05, E231, Luleå tekniska universitet, Luleå, 09:00 (English)
Opponent
Supervisors
Available from: 2019-01-16 Created: 2019-01-15 Last updated: 2019-01-16Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records BETA

Ma, ChunyanXie, YujiaoJi, Xiaoyan

Search in DiVA

By author/editor
Ma, ChunyanXie, YujiaoJi, Xiaoyan
By organisation
Energy Science
In the same journal
Applied Energy
Energy Engineering

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 243 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