Absorption Of Carbon Dioxide with Carbitol Acetate


Thesis Type: Postgraduate

Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2020

Thesis Language: Turkish

Student: İREM KOÇYİĞİT ÇAPOĞLU

Principal Supervisor (For Co-Supervisor Theses): Özkan Murat Doğan

Co-Supervisor: Duygu Uysal

Abstract:

Global warming is one of the most recent and important problem of the world, which is caused by greenhouse gases released to the atmosphere. Carbon dioxide (CO2) is considered to have the highest critical impact that affects global warming amongst all greenhouse gases. Carbon dioxide occurs at the highest rate by burning fossil fuels for power generation and heat. Currently, many researches are carried out to control the carbon dioxide emissions released into the atmosphere. One of the most effective method is to capture carbon dioxide in flue gases at the source of emission into a solution. Alkanolamine solvents are mostly used as absorbent in commercial applications. However, these solvents have several drawbacks related to limited cyclic carbon dioxide loading capacity and the operating cost is fairly high due to the high energy requirement for regeneration of the solution. Therefore, researchers have been focused on finding efficient alternative solutions that may eliminate the disadvantages of the current systems. In this master’s thesis, possibility of using carbitol acetate for carbon dioxide capture was investigated. Carbitol acetate has been preferred because of its thermally stable characteristic, high boiling point, low viscosity, non-corrosivity and its high solubility in water. In addition, carbitol acetate can be easily regenerated and it is structurally suitable for physical absorption of carbon dioxide. With these features, carbitol acetate is a remarkable alternative solution in terms of energy saving and lower cost. Since, there are hardly any studies about using carbitol acetate for absorption of carbon dioxide in literature, studies about parameters that are effective on mass transfer in carbon dioxide-carbitol acetate system were done. Firstly, diffusion coefficients of carbon dioxide in carbitol acetate were determined experimentally using a diaphragm cell system. Theoretical calculations were compared with experimental data which obtained from this part of the study. Then, mass transfer characterization studies were performed using a laboratory scale Raschig ring packed column. In the mass transfer characterization studies, primarily the liquid side and gas side physical individual mass transfer coefficients (𝑘�𝐿�0𝑎� ve 𝑘�𝑐�0𝑎�) were obtained experimentally. Subsequently, the gas-side physical overall mass transfer coefficients (𝐾�𝑐�0𝑎�) were calculated regarding the two-resistance theory for the carbon dioxide-water system. Studies were continued by absorption of carbon dioxide into sodium hydroxide solution. In this means, gas side overall chemical mass transfer coefficients (𝐾�𝑐�𝑎�) were obtained. Finally, absorption of carbon dioxide with carbitol acetate were investigated and gas side overall physical mass transfer coefficients were obtained. In addition, by nonlinear regression method correlations were developed for both systems.