عنوان

Kobalt yüzeylerindeki kükürtün fischer tropsch sentezinin temel raksiyonlarına etkisi

شماره

TL58111

زبان متن نوشتاري يا گفتاري و مانند آن

انگلیسی

عنوان اصلي

Kobalt yüzeylerindeki kükürtün fischer tropsch sentezinin temel raksiyonlarına etkisi

نام عام مواد

[Thesis]

نام نخستين پديدآور

Dağa, Yağmur

نام ساير پديدآوران

Kızılkaya, Ali Can

نام ناشر، پخش کننده و غيره

Izmir Institute of Technology (Turkey)

تاریخ نشرو بخش و غیره

2020

متن يادداشت

103 p.

جزئيات پايان نامه و نوع درجه آن

Master's

کسي که مدرک را اعطا کرده

Izmir Institute of Technology (Turkey)

امتياز متن

2020

متن يادداشت

Industrial observations indicate that sulfur acts a poison for Fischer-Tropsch Synthesis (FTS) and surface science studies show that sulfur blocks the adsorption sites for reactants on cobalt surfaces. However, various experimental studies have indicated conflicting results about the effect of sulfur on cobalt FTS catalyst activity and selectivity. This study aims to clarify the effect of sulfur on cobalt FTS catalysts by molecular modelling of the elementary reactions of FTS on surfaces that are present on sulfur covered cobalt surfaces that are present in fcc-Co nanoparticles, using Density Functional Theory (DFT). For 0.25 ML sulfur coverage, it is found that on bare, C and O covered surfaces, S is the main dissociation product, while HS can be present on low coverages. Atomic sulfur decreases the adsorption energies of all species investigated, while the decrease is more pronounced for CO compared to H2. The effect of S on the elementary FTS reactions direct and H-assisted CO dissociation, carbon hydrogenation, carbon coupling and oxygen removal are also investigated. The results indicate that S inhibits mainly the oxygen removal reaction, in terms of both H2O and CO2. CO dissociation is not inhibited but rather slowed down, due to increasing activation barriers. It is also found that carbon hydrogenation barriers are significantly decreased, while carbon coupling barriers are unaffected. These results indicate that the intrinsic effect of sulfur poisoning would be to increase methane selectivity, while decreasing the selectivity to long chain hydrocarbons.

اصطلاح موضوعی

Catalysis

اصطلاح موضوعی

Chemical engineering

اصطلاح موضوعی

Fischer-Tropsch process

مستند نام اشخاص تاييد نشده

Dağa, Yağmur

مستند نام اشخاص تاييد نشده

Kızılkaya, Ali Can

مستند نام تنالگان تاييد نشده

Izmir Institute of Technology (Turkey)

نام الکترونيکي

فرمت انتشار

p

نوع ماده

[Thesis]

کد کاربرگه

276903

سطح دسترسي

a

تكميل شده

Y