Mass Transfer Performance Study for CO2 Absorption into Non-Precipitated Potassium Carbonate Promoted with Glycine Using Packed Absorption Column

Nur Farhana Ajua Mustafa,Wee Horng Tay,Siti Munirah Mhd Yusof,Azmi Mohd Shariff,Hairul Nazirah Abdul Halim

doi:10.3390/su12093873

Nur Farhana Ajua Mustafa, Wee Horng Tay + Show 3 more

Open Access

https://doi.org/10.3390/su12093873

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Abstract

The removal of carbon dioxide (CO2) at offshore operation requires an absorption system with an environmentally friendly solvent that can operate at elevated pressure. Potassium carbonate promoted with glycine, PCGLY, is a green solvent that has potential for offshore applications. For high solvent concentrations at elevated pressure, the by-product of CO2 absorption consists of precipitates that increase operational difficulty. Therefore, this study was done to assess the CO2 absorption performance of non-precipitated PCGLY with concentration 15wt%PC+3wt%GLY, which is known to have comparable solubility performance with MDEA. A packed absorption column was used to identify the CO2 removal efficiency, mass transfer coefficient in liquid film, k l a e , and overall volumetric mass transfer coefficient, K G a v . A simplified rate-based model was used to determine k l a e and K G a v based on the experimental data with a maximum MAE value, 0.057. The results showed that liquid flow rates and liquid temperature gives significant effects on the k l a e and K G a v profile, whereas gas flow rate and operating pressure had little effect. The CO2 removal efficiency of PCGLY was found to be 77%, which was only 2% lower than 1.2 kmol/m3 MDEA. K G a v of PCGLY is comparable with MDEA. The absorption process using PCGLY shows potential in the CO2 sweetening process at offshore.

Highlights

Carbon dioxide (CO2) concentration in the atmosphere is in critical condition as it has reached the 406.5 ppm threshold [1]
In the gas processing industry, CO2 in raw gas will be removed to its permissible concentration as it is crucial for enhancing the gross heating value of the natural gas and reducing the corrosion risk at the pipelines and equipment
The experimental results indicated that: (1) klae and KGav increased as liquid flow rate and inlet liquid temperature increased; (2) gas flow rate and operating pressure had little effects on klae and KGav; (3) CO2 removal efficiency and KGav value of PCGLY are comparable with MDEA

Summary

Introduction

Carbon dioxide (CO2) concentration in the atmosphere is in critical condition as it has reached the 406.5 ppm threshold [1]. It is considered as the peak level since the past three million years. CO2 release in Malaysia is projected to upsurge by more than 100% in 2030 [2,3] This issue has raised concerns by the industrial sectors to use natural gas (NG) as a fuel, as it is the cleanest fossil fuel. The current technology is still limited to process raw NG with CO2 concentration less than 10% at the onshore purification plant [7]. This problem will cause an increasing demand for NG due to the technology’s limitation in processing CO2-rich NG

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