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Due to the inexpensive cost of amine solvent, more than 95 % of natural gas (NG) processing plants use an acid gas removal unit that utilizes an aqueous amine solvent to remove sour gas components such as carbon dioxide (CO2) and hydrogen sulfide (H2S). Different technologies are available to capture CO2 from NG. However, chemical absorption is the most reliable and used technology all over the world. However, it is challenging to determine the amine blend’s optimal composition for the effective removal of CO2 and H2S and solvent regeneration. This is mainly due to the difference in reservoir gas compositions, affecting gas removal efficiency and solvent regeneration energies. The present investigation addresses the performance of using a novel solvent blend of diisopropanolamine (DIPA) and Triethanolamine (TEA) to determine the absorption capacity of CO2 & H2S using Aspen HYSYS software. A study on the effects of solubility on CO2 absorption was performed at varying pressure (10-80 bar) and temperature (25°C to 50°C). The percentage of CO2 removal increased from 80% to 98% as the temperature increased from 25°C to 50°C. The results revealed that the concentration of CO2 and H2S in sweet gas decrease with the increase in pressure while the concentration of CO2 and H2S increases with the increase in temperature.

Natural gas (NG) requires treatment to eliminate sulphur compounds and acid gases, including carbon dioxide (CO2) and hydrogen sulphide (H2S), to ensure that it meets the sale and transportation specifications. Depending on the region the gas is obtained from, the concentrations of acid gases could reach up to 90%. Different technologies are available to capture CO2 and H2S from NG and absorb them with chemical or physical solvents; occasionally, a mixture of physical and chemical solvents is employed to achieve the desired results. Nonetheless, chemical absorption is the most reliable and utilised technology worldwide. Unfortunately, the high energy demand for solvent regeneration in stripping columns presents an obstacle. Consequently, the present study proposes a novel, ternary-hybrid mixture of N-methyl diethanolamine (MDEA), amino ethyl ethanol amine (AEEA), and N-methyl 2-pyrrolidone (NMP) to overcome the issue and reduce the reboiler duty. The study employed high levels of CO2 (45%) and H2S (1%) as the base case, while the simulation was performed with the Aspen HYSYS® V12.1 software to evaluate different parameters that affect the reboiler duty in the acid gas removal unit (AGRU). The simulation was first validated, and the parameters recorded errors below 5%. As the temperature increased from 35 °C to 70 °C, the molar flow of the CO2 and H2S in sweet gas also rose. Nevertheless, the pressure demonstrated an opposite trend, where elevating the pressure from 1000 kPa to 8000 kPa diminished the molar flow of acid gases in the sweet gas. Furthermore, a lower flow rate was required to achieve the desired specification of sweet gas using a ternary-hybrid blend, due to the presence of a higher physical solvent concentration in the hybrid solvent, thus necessitating 64.2% and 76.8%, respectively, less reboiler energy than the MDEA and MDEA + AEEA.

Introduction We investigated outcomes and prognostic factors for patients treated for cutaneous angiosarcoma (CA). Methods We conducted a retrospective review of patients treated for CA of the face and scalp from 1962 to 2019. All received definitive treatment with surgery, radiation (RT), or a combination (S‐XRT). The Kaplan–Meier method was used to estimate outcomes. Multivariable analyses were conducted using the Cox proportional hazards model. Results For the 143 patients evaluated median follow‐up was 33 months. Five‐year LC was 51% and worse in patients with tumors >5 cm, multifocal tumors, those treated pre‐2000, and with single modality therapy (SMT). These remained associated with worse LC on multivariable analysis. The 5‐year disease‐specific survival (DSS) for the cohort was 56%. Tumor size >5 cm, non‐scalp primary site, treatment pre‐2000, and SMT were associated with worse DSS. Conclusion Large or multifocal tumors are negative prognostic factors in patients with head and neck CA. S‐XRT improved outcomes.