Biogas is a product during anaerobic digestion of organic waste, such as urban sludge, agricultural waste, livestock excreta and industrial effluents. Biogas typically contains 60-70% CH4 (methane), 30-40% CO2, 0-4000 ppm H2S and small amounts of other components. Methane purified from biogas can be used as high value fuel or used to produce chemical products. Methane and carbon dioxide are also the main greenhouse gases which result in global warming effect. Since the global warming potential (GWP) of methane is twenty-five times greater than that of carbon dioxide, the influence of methane on the global warming effect cannot be ignored. In the presence of water, hydrogen sulfide leads to corrosion damage on the instruments and pipelines. Therefore, the separation of CO2 and H2S from biogas for obtaining pure bio-methane and simultaneously highly concentrated CO2 for subsequent sequestration or utilization is important. Pressure swing adsorption (PSA) is one of the most known and established industrial processes for gas separation because of the low energy requirements, low capital investment cost, and simplicity of operation. In this study, we will develop a biogas purification technology by basic experiments and simulation of PSA process. First, we will find the suitable adsorbent from literatures and obtain the parameters of adsorption isotherm from adsorption measurements. To validate the accuracy of adsorbent parameters, we will verify the simulation with the experiment of breakthrough curves. For laboratory safety, we substitute N2 for CH4 in the biogas to employ the experiment and simulation of dual-bed PSA process for N2/ CO2 separation. The simulation program will be verified by comparison with the experimental data and confirm the accuracy of the PSA simulation. Finally, we compare the difference between the result of N2/ CO2 and CH4/ CO2 PSA system by simulation and, at the second year, design a PSA process for H2S/ CH4/ CO2 separation by simulation. After exploring the effects of variables such as bed length, feed pressure, vacuum pressure, and the time of each step, we will find the best operating conditions for obtaining high purity methane (> 99%) and carbon dioxide (> 95%) simultaneously. The results would be helpful to design commercial PSA process in the future.
|Effective start/end date||1/08/19 → 31/07/20|
UN Sustainable Development Goals
In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all. This project contributes towards the following SDG(s):
- Pressure swing adsorption
- Carbon dioxide
- Hydrogen sulfide
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