What Is Acid Gas?

Acidic gases, when dissolved in water, will react to form weak acids, including sulfur oxides, nitrogen oxides and other chemical compounds. These gases are extremely low in the atmosphere and may not even be detected in some areas. The presence of acid gases will increase the corrosion of pipes and equipment and affect their service life. During the low temperature separation of natural gas, CO2 may form dry ice and block pipelines and equipment; natural gas containing more H2S will appear ambiguous during combustion, and compounds such as SO2 generated by combustion will pollute the environment; in catalytic processing, Hydrocarbon compounds can poison the catalyst. Therefore, the removal of acid gases is one of the main tasks of natural gas purification.

Coal technology (first-level discipline);

An acid gas is one that can react with an alkali to form a salt.

CO2 {CO2}, Cl2 {

Some acid gases are harmful to us, for example, if the air is polluted, it contains sulfur dioxide,

Laboratory has

Chemisorption

The chemical absorption method refers to a chemical process using a weakly alkaline substance or an aqueous solution to react with an acid gas in natural gas, and mainly includes the following methods:

(1) Alkali washing method.

The alkaline washing method uses NaOH solution to wash natural gas. During the washing process, NaOH chemically reacts with H ₂ S and CO ₂ in the natural gas to generate carbonates and sulfides and dissolve in the waste alkaline solution, thereby removing acid gases from the natural gas. Get rid of.

(2) Alcohol-amine method.

The alcohol amine method belongs to a method combining chemical reaction and physical absorption. Commonly used alcohol amines are: monoethanolamine; diethanolamine; diethylene glycol amine; triethanolamine.

The molecular structure of alcohol amines shows at least one hydroxyl (-OH) and one amino (-NH ₂ or --NH). Among them, the hydroxyl group can increase the solubility of alcohol amines in water, and can reduce the vapor pressure of compounds; the amino group is alkaline in aqueous solution, which promotes its absorption of acid gases. When alcohol amines are used to remove acid gases, alcohol amine solutions are generally formulated as 10% to 30% aqueous solutions. Since the reaction between alcohol amine and acid gas is reversible, we can use heating, low pressure (or stripping) to purify the alcohol amine, so as to achieve the regeneration cycle of the alcohol amine ^[2]

From strong to weak, they are: perchloric acid, hydroiodic acid, sulfuric acid, hydrobromic acid, hydrochloric acid, nitric acid, and iodic acid (the above are strong acids, you can understand, the university involves strong and weak ordering), oxalic acid (oxalic acid), Sulfurous acid, phosphoric acid, pyruvate, nitrous acid (the above five are moderately strong acids), citric acid, hydrofluoric acid, malic acid, gluconic acid, formic acid, lactic acid, benzoic acid, acrylic acid, acetic acid, propionic acid, stearic acid, Carbonic acid, hydrosulfuric acid, hypochlorous acid, boric acid, silicic acid, phenol (the rest are weak or very weak acids)!