Low Temperature Desulfurization And Regeneration Performance Of CuO-Based Adsorbents

Recovery of CO₂ is of great significance for carbon resources utilization and environmental protection.The high concentration of CO₂ which produced from production process such as chemical fertilizers and alcohol is the high quality gas source for the production of food grade quality CO₂· However,it always contains some impurities such as hydrogen sulfide?H₂S?which limit the use of the CO₂.H₂S is a kind of destructive impurity gas.It will not only pollute the environment and endanger human health,but also corrode the equipment and pipelines.In order to remove it from the CO₂ gas source effectively,different types of sorbents are widely used in the current industrial production.However,the low-temperature H₂S adsorbents used in industrial recently suffered from several problems,such as,low sulfur capacity,low desulfurization precision and difficult to regeneration.The development of regenerable and high desulfurization efficiency adsorbents is an important area of study.In this study,the low temperature desulfurization ablity of CuO-based adsorbents were investigated,the effects of preparation methods,additives and supported materials to the the structure,desulfurization and regeneration performance of CuO-based adsorbents were also studied.Some conclusions are drawn from this work as follows:1.The CuO adsorbents were prepared by precipitation and sol-gel methods,the effects of preparation methods to the the structure and desulfurization performance were investigated.The effects of regeneration temperature,regeneration gas and desulfurization regeneration cycle on the regeneration performance of adsorbents were also studied.The results showed that H₂S can be removed from CO₂ gas by CuO to less than 0.1 ppm.The specific surface area,grain size and morphology of CuO synthesized by different preparation methods are quite different.The CuO prepared by precipitation method has a higher breakthrough capacity,which is 17.7 mg g^-1.The results of four consecutive desulfurization and regeneration cycles revealed that the used CuO can be regenerated with air at 100? and regeneration performance remained stable.2.In order to improve the desulfurization performance of CuO,a series of CuO-based binary and ternary mixed metal oxides adsorbents were prepared.The relationship between the composition of the active components and the desulfurization performance was investigated in detail.It was found that the introduction of aluminum,iron and cerium elements had an important effect on the structure of CuO-based adsorbents and the dispersion of active components.Additives should not be added too much,otherwise they will inhibit the desulfurization performance.Among them,Al-doped binary CuO-based adsorbents,the highest breakthrough capacity reached 86.0 mg g^-1.Fe and Ce doped ternary CuO-based adsorbents,the highest breakthrough capacity reached 113.9 and 94.1 mg g^-1,respectively.3.In order to further improve the desulfurization performance of CuO,a series of supported CuO-based adsorbents were prepared by coprecipitation impregnation method.The effects of carrier type and content on desulfurization performance were studied.The results showed that textural properties as well as the active components play an important role in the desulfurization process.Compared with CuO,the specific surface area,the dispersion of the active components and the desulfurization performance of the CuO-based adsorbents with the addition of the carrier were improved.The adsorbents with appropriate amount MCM-41 and SBA-15 exhibited the highest breakthrough capacity,which is 199.8 and 202.4 mg g^-1,respectively.4.In order to optimize the use of the adsorbents,the main factors affecting desulfurization performance were investigated by adjusting the conditions such as calcination temperature,impurity gas type,reaction space velocity and temperature,and the optimum preparation and reaction conditions were explored.The results show that the increase of the calcination temperature will cause the sintering of the adsorbents and the decrease of the specific surface area and the desulfurization performance.The optimum calcination temperature o is 350?.H₂O and CO have little effect on the desulfurization performance of the adsorbents,but the balance gas CO₂ will inhibit the H₂S adsorption.The space velocity has a great influence on the desulfurization performance,and the breakthrough capacity decreases with the increase of the space velocity.The adsorption temperature has different effects on different adsorbents,the appropriate desulfurization temperature should be no higher than 100? in order to avoid the generation of other sulfur-containing impurities.