Solubility of Hydrogen Sulfide in Aqueous Solutions of N-Methyldiethanolamine and Piperazine

Abstract

The solubility of hydrogen sulfide in an aqueous mixture of 2,2′-methyliminodiethanol (N-methyldiethanolamine, [CAS 105-59-9], MDEA) and 1,4-diazacyclohexane (piperazine, [CAS 110-85-0], PIPH2) was measured over a wide range of gas-loadings (stoichiometric molar ratios of hydrogen sulfide to (MDEA + PIPH2) between about 0.014 and 1.67) at three temperatures (about 313 K, 353 K, and 393 K) by headspace gas chromatography as well as by a synthetic gas solubility method. The molality of MDEA in the aqueous mixture was about 4.5 mol·(kg water)−1 and that of PIPH2 about 1.6 mol·(kg water)−1. The headspace gas chromatography technique was applied in the low pressure range (partial pressure of H2S between 0.64 and 125.7 kPa, stoichiometric molar ratio of H2S to (MDEA + PIPH2) between about 0.014 and 0.73). The synthetic method was applied in the high pressure range (total pressure between 0.2 and 5.5 MPa, stoichiometric molar ratio of H2S to (MDEA + PIPH2) between about about 0.51 and 1.67). The new experimental results are compared to prediction results from a thermodynamic model that was parametrized using only experimental results for the solubility of H2S data in the aqueous solution of the single amines in the high pressure range.

Vapor–Liquid Equilibria of H2S in Aqueous Mixtures of N-Methyldiethanolamine + Piperazine + Sulfolane

“…However, there are no data on the solubility of H 2 S in MDEA + PZ + SFL mixed solvent. In recent years, some H 2 S equilibrium solubility measurements in alkanolamine solutions have been reported in three categories of MDEA, MDEA-based, ,− and non-MDEA-based ,,,− solutions in aqueous and hybrid context with and without inert gas makeup. ,,,− The corresponding reports, together with the temperature and pressure ranges, are shown in Table .…”

Absorption and Removal Efficiency of Low-Partial-Pressure H2S in a Monoethanolamine-Activated N-Methyldiethanolamine Aqueous Solution

“…Coke oven gas (COG) is widely used as a high-temperature furnace fuel and city gas to enhance energy efficiency. , However, the existence of hydrogen sulfide (H 2 S) in COG can cause equipment corrosion in the industry and also endanger the environment and human health. − Thus, it is necessary to remove H 2 S from GOC (residual contents ≤ 0.5 g/m 3 according to Chinese cleaner production standard: Coking industry, HJ/T 126-2003). H 2 S from GOC can be removed by chemical absorption using aqueous solution of diethanolamine (DEA), diisopropanolamine (DIPA), monoethanolamine (MEA), and N -methyldiethanolamine (MDEA). − The aqueous alkanol amine solution absorbs acid gas at approximately ambient temperature via a reversible chemical reaction. At a higher temperature (approximately 393 K), the absorbed acid gas can be released and the solvent can be regenerated …”

“…H 2 S from GOC can be removed by chemical absorption using aqueous solution of diethanolamine (DEA), diisopropanolamine (DIPA), monoethanolamine (MEA), and N -methyldiethanolamine (MDEA). − The aqueous alkanol amine solution absorbs acid gas at approximately ambient temperature via a reversible chemical reaction. At a higher temperature (approximately 393 K), the absorbed acid gas can be released and the solvent can be regenerated …”

“…At a higher temperature (approximately 393 K), the absorbed acid gas can be released and the solvent can be regenerated. 10 In particular, aqueous MEA solutions have been widely used to remove H 2 S. 11 Lee et al 12 measured the solubility of H 2 S in 2.5 and 5.0 N MEA solutions under 298−393 K and partial pressure of H 2 S (P H 2 S ) ranging from 0.15 to 2370 kPa. Jane et al 13 measured the solubility of H 2 S in 2.5 N MEA solutions at 353 K. However, the major disadvantages of MEA aqueous solutions are the high energy cost for their regeneration and high corrosion to equipment.…”

Mutual Solubilities of Cyclohexane and Water in Aqueous Methyldiethanolamine /Cyclohexane Liquid–Liquid Equilibria

“…The contact between hydrocarbons and aqueous alkanolamine has been studied and is still considered one of the common features in the physical separation processes in most refineries and petrochemical plants, mainly in the areas of where crude oil and natural gas streams should be treated for acid gas removal , and in extraction towers.…”