Optimization of gas-methane-number-upgrading process

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School of Chemical Engineering | Master's thesis
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Date

2012

Department

Kemian laitos

Major/Subject

Teknillinen kemia

Mcode

Kem-40

Degree programme

Language

en

Pages

viii + 73 + [12]

Series

Abstract

The target of this Master's Thesis was to reduce the water consumption costs in a pre-reforming process, where a hydrocarbon gas mixture with a low methane number (MN) was mixed with steam to produce gas with a high methane number but without coke formation on the catalyst surface. The literature review presents the prereforming techniques, how the steam to carbon ratio (S/C) affects the coke formation in reforming processes, as well as some sea water purification methods. In addition, the production and consumption of electricity offshore is described. In the experimental part, different S/C ratios were examined at three temperatures to observe whether coke was formed on a nickel catalyst in a pre-reforming reactor. The used S/C ratios were 0.6, 0.9, and 1.2, while the temperatures were 350 °C, 400 °C, and 450 °C, respectively. The effect of carbon dioxide addition on coke formation was also Investigated applying temperature of 400 °C and the S/C ratio 1.3. A small amount of coke was formed in all experiments and the coke amount was increasing with lower S/C ratio at 400 °C. At all other temperatures and S/C ratios the coke formation was hazardous but low and no obvious trend could be determined. The formed coke amount in the experiments with carbon dioxide was in the same order of magnitude as in the experiments without CO<sub>2</sub> indicating that the feed composition did not affect the coke formation. The MN of the obtained product gases was higher than 85 in all experiments and the highest MNs were obtained in the experiments with CO<sub>2</sub>, According to this study, it is possibly to apply a lower S/C ratio in the pre-reforming process, since the amount of the formed coke was very low in all experiments.

Description

Supervisor

Lehtonen, Juha

Thesis advisor

Ruohomäki, Jaakko
Karinen, Reetta

Keywords

methane number, metantal, S/C ratio, S/C förhållande, pre-reforming, förreformering

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Permanent link to this item

https://urn.fi/URN:NBN:fi:aalto-2020122859269

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[dipl] Kemian tekniikan korkeakoulu / CHEM