Study Of Purification Technology Of Acid Gas H₂S In Natural Gas

Natural gas is a clean and green resource of energy as an alternative to crude oil.However,H2S in natural gas would not only pose a serious threat to the organisms and human health,but also lead to equipment corrosion and catalyst poisoning.Therefore,the removal of H2S from natural gas is of great practical significance in upgrading gas quality,protecting the environment,reducing air pollution,and improving the economic and social benefits of natural gas.In this work,a mixture of H2S and N2 was used to simulate natural gas.An absorption method by organic alkanolamine and an adsorption method by modified activated carbon were adopted to remove the acid H2S,respectively.The main research contents and results were as follows.(1)The experimental apparatus for determining H2S solubility in alkanolamine was set up.In the solvent absorption process,the effects of absorbent type,absorbent concentration,and absorption temperature on the solubility of H2S were investigated.A suitable H2S solubility in MDEA was obtained at MDEA concentration of 2.5 mol/L and absorption temperature of 25 ℃.Aspen HYSYS and Aspen Plus Software were used for the simulation of absorption process,and better agreement between the simulated results and experimental data was observed using Aspen HYSYS,which may be demonstrated more applicable to this system.(2)The MDEA absorption process was optimized in a continuous absorption-desorption apparatus.The influences of process parameters such as absorbent concentration,absorption temperature,gas volume flowrate,and desorption temperature on desulfurization performance were investigated.The maximum H2S absorption in MDEA reached 341.8 mg/L at MDEA concentration of 2.5 mol/L,absorption temperature of 25 ℃,gas volume flowrate of 40 mL/min,and desorption temperature of 90 ℃.The simulation results of Aspen HYSYS are in a good agreement with the experimental results.(3)Tricobalt tetroxide loaded activated carbon absorbents(C03O4/AC)were prepared via immersion process.The effects of preparation conditions and process conditions on the desulfurization performance of absorbents were investigated.The absorbent prepared from a immersion solution with 8 wt.%cobalt nitrate in water at calcination temperature of 300 ℃and calcination time of 2 h exhibited better desulfurization performance.The maximum H2S saturation capacity and total H2S removal rate were 189.0 mg/g and 56.6%at oxygen content in the feed gas of 2%,gas volume flowrate of 20 mL/min,and adsorption temperature of 40℃.Kinetics of adsorptive removal of H2S over the Co3O4/AC adsorbent followed the Bangham model.A desirable adsorption kinetics rate equation was obtained by fitting analysis.(4)Zinc oxide loaded activated carbon absorbents(ZnO/AC)were prepared via immersion process.The effects of preparation conditions and process conditions on the desulfurization performance of absorbents were investigated.The absorbent prepared from a immersion solution with 5 wt.%zinc nitrate in water at calcination temperature of 300 ℃and calcination time of 2 h exhibited better desulfurization performance.The maximum H2S saturation capacity and total H2S removal rate were 339.9 mg/g and 66.6%at oxygen content in the feed gas of 2%,gas volume flowrate of 20 mL/min,and adsorption temperature of 60℃.Kinetics of adsorptive removal of H2S over the ZnO/AC adsorbent followed the Bangham model.A desirable adsorption kinetics rate equation was obtained by fitting analysis.(5)Copper oxide loaded activated carbon absorbents(CuO/AC)were prepared via immersion process.The effects of preparation conditions and process conditiong on the desulfurization performance of absorbents were investigated.The absorbent prepared from a immersion solution with 8 wt.%copper nitrate in water at calcination temperature of 300 ℃and calcination time of 2 h exhibited better desulfurization performance.The maximum H2S saturation capacity and total H2S removal rate were 343.6 mg/g and 75.3%at oxygen content in the feed gas of 2%,gas volume flowrate of 20 mL/min,and adsorption temperature of 60℃.Kinetics of adsorptive removal of H2S over the CuO/AC adsorbent followed the Bangham model.A desirable adsorption kinetics rate equation was obtained by fitting analysis.(6)Manganese dioxide loaded activated carbon absorbents(MnO2/AC)were prepared via coprecipitation process.The effects of preparation conditions and process conditions on the desulfurization performance of absorbents were investigated.The absorbent prepared at manganese dioxide to activated carbon ratio of 1.1:1,calcination temperature of 250 ℃ and calcination time of 2 h exhibited better desulfurization performance.The maximum H2S saturation capacity and total H2S removal rate were 713.3 mg/g and 89.9%at oxygen content in the feed gas of 2%,gas volume flowrate of 20 mL/min,and adsorption temperature of 40℃.Kinetics of adsorptive removal of H2S over the Mn02/AC adsorbent followed the Bangham model.A desirable adsorption kinetics rate equation was obtained by fitting analysis.