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
Integration of Hybrid Cycles in Bio-Methanol Production
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
(English)In: Environmental Impact of Energy SystemArticle in journal (Other academic) Submitted
Abstract [en]

In bio-based methanol production approximately 60% of the biomass energy content is converted into methanol, the remaining part can be recovered as thermal heat. Efficient utilization of the thermal heat is difficult in stand-alone methanol plants. The overall efficiency is to a large extent dependent on the further conversion of power due to the significant quantity of excess heat. Heat can be recovered in a steam cycle but due to poor steam data energy efficiency is low. This paper therefore proposes the integration of a natural gas fired gas turbine. Simulations of the hybrid cycle in methanol production have shown good improvements. The total electrical efficiency is increased by 1.4-2.4 percentage points, depending on the fuel mix. The electrical efficiency for the natural gas used in the hybrid plant is 56-58%, which is in the same range as in large-scale combined cycle plants. A bio-methanol plant with a hybrid power cycle is therefore a competitive production route for both biomass and natural gas.

Keyword [en]
Bio-Methanol, Biomass, Gasification, Hybrid Cycles, Polygeneration
National Category
Energy Engineering
Identifiers
URN: urn:nbn:se:kth:diva-29249OAI: oai:DiVA.org:kth-29249DiVA: diva2:392836
Note
QS 20120326Available from: 2011-01-28 Created: 2011-01-28 Last updated: 2012-11-27Bibliographically approved
In thesis
1. Turbomachinery in Biofuel Production
Open this publication in new window or tab >>Turbomachinery in Biofuel Production
2011 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The aim for this study has been to evaluate the integration potential of turbo-machinery into the production processes of biofuels. The focus has been on bio-fuel produced via biomass gasification; mainly methanol and synthetic natural gas. The research has been divided into two parts; gas and steam turbine applications.

Steam power generation has a given role within the fuel production process due to the large amounts of excess chemical reaction heat. However, large amounts of the steam produced are used within the production process and is thus not available for power production. Therefore, this study has been focused on lowering the steam demand in the production process, in order to increase the power production. One possibility that has been evaluated is humidification of the gasification agent in order to lower the demand for high quality steam in the gasifier and replace it with waste heat. The results show that the power penalty for the gasification process could be lowered by 18-25%, in the specific cases that have been studied.

Another step in the process that requires a significant amount of steam is the CO2-removal. This step can be avoided by adding hydrogen in order to convert all carbon into biofuel. This is also a way to store hydrogen (e.g. from wind energy) together with green carbon. The results imply that a larger amount of sustainable fuels can be produced from the same quantity of biomass.

The applications for gas turbines within the biofuel production process are less obvious. There are large differences between the bio-syngas and natural gas in energy content and combustion properties which are technical problems when using high efficient modern gas turbines. This study therefore proposes the integration of a natural gas fired gas turbine; a hybrid plant. The heat from the fuel production and the heat recovery from the gas turbine flue gas are used in a joint steam cycle. Simulations of the hybrid cycle in methanol production have shown good improvements. The total electrical efficiency is increased by 1.4-2.4 percentage points, depending on the fuel mix. The electrical efficiency for the natural gas used in the hybrid plant is 56-58%, which is in the same range as in large-scale combined cycle plants. A bio-methanol plant with a hybrid power cycle is consequently a competitive production route for both biomass and natural gas.

Place, publisher, year, edition, pages
Stockholm: KTH, 2011. iv, 39 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2011:2
Keyword
Bio-Methanol, Biomass, Gasification, Humidification, Hybrid Cycle, SNG
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-28901 (URN)978-91-7415-835-9 (ISBN)
Presentation
2011-01-21, V3, Teknikringen 76, 2 tr, KTH, Stockholm, 13:00 (Swedish)
Opponent
Supervisors
Note
QC 20110128Available from: 2011-01-28 Created: 2011-01-24 Last updated: 2011-01-28Bibliographically approved
2. Energy system evaluation of thermo-chemical biofuel production: Process development by integration of power cycles and sustainable electricity
Open this publication in new window or tab >>Energy system evaluation of thermo-chemical biofuel production: Process development by integration of power cycles and sustainable electricity
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Fossil fuels dominate the world energy supply today and the transport sector is no exception. Renewable alternatives must therefore be introduced to replace fossil fuels and their emissions, without sacrificing our standard of living. There is a good potential for biofuels but process improvements are essential, to ensure efficient use of a limited amount of biomass and better compete with fossil alternatives. The general aim of this research is therefore to investigate how to improve efficiency in biofuel production by process development and co-generation of heat and electricity. The work has been divided into three parts; power cycles in biofuel production, methane production via pyrolysis and biofuels from renewable electricity.

The studies of bio-based methanol plants showed that steam power generation has a key role in the large-scale biofuel production process. However, a large portion of the steam from the recovered reaction heat is needed in the fuel production process. One measure to increase steam power generation, evaluated in this thesis, is to lower the steam demand by humidification of the gasification agent. Pinch analysis indicated synergies from gas turbine integration and our studies concluded that the electrical efficiency for natural gas fired gas turbines amounts to 56-58%, in the same range as for large combined cycle plants. The use of the off-gas from the biofuel production is also a potential integration option but difficult for modern high-efficient gas turbines. Furthermore, gasification with oxygen and extensive syngas cleaning might be too energy-consuming for efficient power generation.

Methane production via pyrolysis showed improved efficiency compared with the competing route via gasification. The total biomass to methane efficiency, including additional biomass to fulfil the power demand, was calculated to 73-74%. The process benefits from lower thermal losses and less reaction heat when syngas is avoided as an intermediate step and can handle high-alkali fuels such as annual crops.

Several synergies were discovered when integrating conventional biofuel production with addition of hydrogen. Introducing hydrogen would also greatly increase the biofuel production potential for regions with limited biomass resources. It was also concluded that methane produced from electrolysis of water could be economically feasible if the product was priced in parity with petrol.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2012. v, 68 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2012:59
Keyword
Biomass, Gasification, Methane, SNG, Power to Gas, Pyrolysis
National Category
Energy Systems Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-105814 (URN)978-91-7415-835-9 (ISBN)
Public defence
2012-12-14, Sal E3, Osquarsbacke 14, KTH, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

QC 20121127

Available from: 2012-11-27 Created: 2012-11-27 Last updated: 2012-11-27Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Görling, MartinWestermark, Mats
By organisation
Energy Processes
Energy Engineering

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 348 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