Amine-Based Solvents for Carbon Dioxide Absorption

Carbon dioxide emission is one of the most concerning issues worldwide. Emissions of other greenhouse gases also contribute significantly to global warming.

Electricity generation is at the forefront of activities causing carbon dioxide formation. Specifically, in electricity generation using fossil fuels, the share of total CO2 emissions is 41%. Due to the low cost of fossil fuels like coal in energy production, electricity generation from coal in this field is increasing every day with the opening of new coal mines.

How to Reduce Carbon Dioxide Emissions?

Carbon capture and storage systems can provide an advantage for the use of fossil fuels in energy production and offer significant opportunities to reduce CO2 emissions.

One of the newest technologies for reducing carbon dioxide emissions stands out as the carbon dioxide capture method.

In the energy sector, to make post-combustion carbon dioxide capture more economical and efficient, there is a need to research solvents that require less energy, experience lower solvent loss, and lead to lower corrosion rates.

Therefore, the focus should be on energy-efficient amine-based solvent types for CO2 absorption. Thus, the molecular structure of the solvent plays an important role in its absorption properties. Within the preferred solvent, primary and secondary amine groups react with carbon monoxide (CO) to form carbamates. In contrast, tertiary amines cannot react because they do not have free protons.

Due to these properties, tertiary amines act as bases. Sodium bicarbonate is formed because of the chemical properties provided by their basic nature. The most important factors affecting absorption capacity and regeneration energy are carbamate stability and basicity.

What Are the Factors Affecting Carbon Dioxide Emissions?

The properties of chemical compounds used to capture carbon dioxide from flue gases hold an important place. The most significant factors affecting these are the carbamate stability of the solvent, which are key factors in quantum mechanics.

These are based on molecular structure effects, including the length of carbon chains, steric hindrance, the presence of functional groups, and different cyclic amine configurations.

An increase in the chain lengths of amine and different functional groups within the absorbent structure leads to a decrease in the absorption rate.

It has been determined that steric hindrance occurs if there is an alkyl group side chain on the alpha-carbon adjacent to the amine group within the absorbent structure.

It has been determined that aromatic amine groups substituted with alkyl groups show a slight increase in initial absorption rate and absorption capacity.

What is Carbon Capture and Storage?

Carbon capture and storage is defined as a technology system that integrates CO2 capture, transport, and storage. This system has been used for many years. Additionally, systems with lower costs than CCS also serve as carbon capture and storage solutions.

In CO2 capture systems, there are many different types of systems for removing CO, which is an undesirable pollutant in the atmosphere, from this gas stream.

There are 3 different methods for capturing carbon dioxide. These are post-combustion capture, pre-combustion capture, and oxy-fuel process operations.

Post-combustion capture processes involve cleaning the CO2 from the flue gas after a combustion process. Oxy-fuel combustion refers to the combustion of fuel using pure oxygen. This results in a gas rich in CO2 content.

Post-Combustion Carbon Dioxide Capture

After combustion, alkanolamines are used as commercial solutions for acidic gases. Many studies have been conducted for this purpose. Triethanolamine was the first commercially available alkanolamine. Subsequently, other alkanolamines have gained a place in the market for acid-gas absorbent systems.

In addition to Triethanolamine (TEA), Monoethanolamine (MEA), Diethanolamine (DEA), and Methyldiethanolamine (MDEA) are other alkanolamines used in gas purification systems.

Triethanolamine has the lowest carbon dioxide emission. It has low reactivity due to the absence of a free hydrogen atom.

Although Diisopropanolamine (DIPA) has been used in many gas purification processes, it has been replaced by Methyldiethanolamine (MDEA) over time. The most important considerations in these applications are high corrosion resistance, prevention of carbon monoxide emissions, and increasing the absorption rate.

Why Are Amine Derivatives Important for Performing Carbon Dioxide Absorption?

Because amines contain a functional group that can chemically bind carbon dioxide by taking it from the atmosphere or a solution. This can reduce the concentration of carbon dioxide in the atmosphere and therefore mitigate environmental issues such as the greenhouse effect and climate change. Additionally, amine derivatives can be used in artificial systems that absorb and carry carbon dioxide.

These systems are designed to clean and store carbon dioxide from waste gases resulting from industrial activities or other sources. In this context, amine derivatives are of critical importance for the effective absorption and removal of carbon dioxide.