Change search
ReferencesLink to record
Permanent link

Direct link
Pyrolysis of Wood Chips: Influence of Pyrolysis Conditions on Charcoal Yield and Charcoal Reactivity
Luleå University of Technology, Department of Engineering Sciences and Mathematics.
2016 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

At a steel mill, charcoal from biomass is a potential substitute to coal as a reducing agent in the Blast Furnace. The steel industry accounts for 5 % of the global CO2 emissions. Charcoal, being a renewable fuel, has the potential to mitigate the steel industry’s contribution to global warming. If charcoal were to replace the pulverized coal injected into one of Sweden´s two blast furnaces an estimated 1,13 Mton raw biomass per year would be required, this is equivalent to 2,5 % of the total available biomass in Sweden the year 2020 . If this is to be realized, a well optimized pyrolysis process for charcoal production would be required, a process with high charcoal yield that minimize the biomass consumption. This report presents a study on pyrolysis of wood chips. The two main objectives of this work have been to find pyrolysis conditions, applicable in a real process, that increase the charcoal yield and also to investigate how the reactivity of the charcoal is affected by these conditions. A hypothesis with two approaches has been proposed and evaluated experimentally. It has been proposed that the charcoal yield is increased if the tar found in the pyrolysis gases are condensed and returned to impregnate the ingoing wood before undergoing a second pyrolysis step. Or, the charcoal yield is increased by letting the tar impregnate the outgoing charcoal before the two undergoes a second pyrolysis step. The hypothesis has been evaluated in a laboratory where pyrolysis has been conducted on chips from fir wood together with bio-oil. The bio-oil has been used to resemble tar. It has been concluded that by recycling tar the charcoal yield is increased. Pyrolysis of fir wood at 340 oC yields 32 % charcoal. If the wood is impregnated before the pyrolysis with an amount of bio-oil equivalent to a tar yield of 25 % the charcoal yield is increased to 37,7 %. It is possible to say, with 80 % confidence, that pyrolysis of wood and bio-oil gives a higher charcoal yield if the two undergoes pyrolysis while being in contact with each other instead of being separated. The charcoal yield is not increased by pyrolysis of charcoal impregnated with bio-oil. There is no difference in reactivity between charcoals from impregnated wood and plain wood.

Place, publisher, year, edition, pages
2016. , 29 p.
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:ltu:diva-179OAI: oai:DiVA.org:ltu-179DiVA: diva2:972188
Educational program
Sustainable Energy Engineering, master's level
Supervisors
Examiners
Available from: 2016-11-08 Created: 2016-09-20 Last updated: 2016-11-08Bibliographically approved

Open Access in DiVA

fulltext(2120 kB)24 downloads
File information
File name FULLTEXT01.pdfFile size 2120 kBChecksum SHA-512
c922700744aea7cc9787b0dde1298f04de53c4fa37594e4bc030cbcc93d2d88421346c909c348c420869c8acfd8a1af6d65b570a3326c61bfa88813ee2081adf
Type fulltextMimetype application/pdf

By organisation
Department of Engineering Sciences and Mathematics
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar
Total: 24 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

Total: 14 hits
ReferencesLink to record
Permanent link

Direct link