Separation of [formula omitted] mixtures by layered pressure swing adsorption for upgrade of natural gas

A compact adsorption-based process for removal of carbon dioxide and nitrogen from natural gas has been discussed. Among the adsorption-based processes, especially, the pressure swing adsorption (PSA) process has been a suitable unit operation for the purification and separation of gas because of low operation energy and cost. A step cycle is made up of pressurization, feed, equalization, blowdown and rinse. In this work, the PSA process is composed of zeolite 13X and carbon molecular sieve (CMS) for removal of carbon dioxide and nitrogen from mixed gas containing (75:21:4 vol%). A CMS selectively removes carbon dioxide and a zeolite 13X separates nitrogen from methane. CMS is investigated experimentally due to the high throughput of the faster diffusing component (). The gas composition of top, bottom and feed tank was measured with the gas chromatography (GC) using TCD detector, helium as carrier gas and packed column for analysis of methane, carbon dioxide, and nitrogen.

A vacuum pressure swing adsorption (VSA-PSA) process is studied for the removal of carbon dioxide in a contaminated stream of natural gas to achieve fuel grade methane. The adsorbent used was zeolite 13X (CECA) where CO2 is strongly adsorbed. A Skarstrom-type cycle comprising pressurization with product, feed, countercurrent blowdown, and countercurrent purge was employed. A mixture having 60% CH4/20% CO2/20% N2 was used, and two different temperatures were evaluated in a single-column VSA-PSA unit. Under the conditions tested, CO2 was removed to levels lower than 2% as required by fuel grade methane with methane recovery higher than 80% without recycle. This separation process also helps in the CH4−N2 separation. A bidisperse (macropore−micropore) model also including distributed energy balances in gas, solid, and column wall considering heat and mass transfer resistance at the gas−solid interface was used to simulate the VSA-PSA behavior and compare with experiments. Also, some scale-up considerations are considered and evaluated by simulations of the process.

Kinetic separation of carbon dioxide from hydrocarbons using carbon molecular sieve

The potential of direct air capture using adsorbents in cold climates.

Parallel and series multi-bed pressure swing adsorption processes for H2 recovery from a lean hydrogen mixture

Biocatalysis in polymer science

PSA Processes for Recovery of Carbon Dioxide

Pressure swing adsorption for carbon dioxide sequestration from exhaust gases

Performance evaluation of clinoptilolite and 13X zeolites in CO2 separation from CO2/CH4 mixture

Dynamic adsorption–desorption measurements of CO2 and CH4 in amino-MIL-53(Al) were carried out in an adsorption breakthrough setup at different temperatures (303, 318, and 333 K) and pressures (1, 5, and 30 bar) to study the desorption dynamics of CO2 in amino-MIL(Al) as it plays an important role in the design of pressure swing adsorption (PSA) process for the upgrading of biogas. 13X zeolite was used as a reference material. The dynamic adsorption selectivity as well as the desorption efficiency of CO2 in both amino-MIL-53(Al) and 13X zeolite were calculated to evaluate the potential of amino-MIL-53(Al) for the upgrading of biogas by PSA process.

The effect of number of pressure equalization steps on the performance of pressure swing adsorption process

An improved vacuum pressure swing adsorption process with the simulated moving bed operation mode for CH4/N2 separation to produce high-purity methane

Assessment of the energy consumption of the biogas upgrading process with pressure swing adsorption using novel adsorbents

This work focuses on the production of pipeline grade methane from landfill gas (LFG). Vacuum pressure swing adsorption technology using a kinetic adsorbent, Carbon Molecular Sieve 3K (Takeda), was employed for the separation of methane−carbon dioxide mixture. Adsorption equilibrium and kinetics of methane and carbon dioxide are reported at 298, 308, and 323 to model the adsorption-based process. A four-step Skarstrom-type cycle was employed comprising pressurization, feed, counter-current blowdown, and counter-current purge with product. Co-current pressurization with feed stream and counter-current pressurization with product were evaluated. The separation of a mixture of CH4 (55%)−CO2 (45%) was tested using two different four-step cycles: pressurization with feed stream, feed, blowdown, and purge with product and pressurization with product, feed, blowdown, and purge with product. The results indicate that purity of methane higher than 96% can be obtained with recovery higher than 75%. The difference ...

In order to reduce carbon dioxide emissions, pressure swing adsorption (PSA) process was studied to capture carbon dioxide from flue gas in a coal-fired power plant. Pressure swing adsorption features its low energy consumption, low investment, and simple operation. This study aims to capture carbon dioxide from flue gas by PSA process for at least 85 % CO2 purity and with the other stream of more than 90 % N2 purity. To validate the accuracy of the PSA simulation program, the extended Langmuir-Freundlich equation was adopted to fit measured equilibrium data to describe the adsorption equilibrium of adsorbent zeolite 13X. Next, the simulation study used the linear driving force model and compared the results of breakthrough curves and desorption curves between experiments and simulation to verify the accuracy of the mass transfer coefficient kLDF value in linear driving force model. The agreement between experimental data and the simulation results is good. Further, the simulation was verified with the 100-hour cyclic-steady-state experiment of the 3-bed 9-step PSA process studied. Flue gas after desulphurisation and water removal (13.5 % CO2, 86.5 % N2) of subcritical 1 kW coal-fired power plant was taken as feed to the designed 3-bed 9-step PSA process. To find the optimal operating conditions, the central composite design (CCD) was used. After analysis, optimal operating conditions were obtained to produce a bottom product at 89.20 % CO2 purity with 88.20 % recovery, and a top product at 98.49 % N2 purity with 93.56 % recovery. The mechanical energy consumption was estimated to be 1.17 – 1.41 GJ/t-CO2.