Propane Adsorption by PSA using CMS (Carbon Molecular Sieve)
Propane Adsorption by PSA using CMS (Carbon Molecular Sieve)
During petroleum refining and thermal decomposition of feedstock oil, gases containing propane and propylene are generated.
Propane gas can be effectively reused as energy.
The current technology for propane/propylene adsorption is cryogenic separation, a highly energy consuming process. Osaka Gas Chemicals has focused on the development of CMS (Carbon Molecular Sieve) specially designed for this application. It is a state-of-the-art method and low cost.
Along with providing lab samples, we will also support customization. Please feel free to consult us.
Characteristics of PSA
The adsorption capacity of activated carbon for gases is influenced by various conditions such as temperature, total gas pressure, partial pressure (concentration) of component gases, and adsorption rate. Among these conditions, the technique of swinging the pressure is called Pressure Swing Adsorption (PSA). In PSA, the adsorption capacity increases with increasing pressure and decreases with decreasing pressure. Therefore, substances adsorbed onto activated carbon under pressurized conditions can be desorbed by reducing the pressure. PSA does not require thermal energy and can vary the adsorption and desorption conditions by increasing or decreasing the pressure, enabling high-speed swing cycles. Figure 1 shows the basic flow of a normal pressure regeneration PSA system. The feed gas is first pressurized and then introduced into an adsorption tower A filled with CMS. While the components that are easily adsorbed are adsorbed under pressure, the components that are difficult to adsorb are taken out of the tower as product gas. When the components that are easily adsorbed leak from the outlet side of adsorption tower A, the operation is switched to adsorption tower B, and the pressure of adsorption tower A is reduced. As a result, the components adsorbed in adsorption tower A are desorbed and become adsorbable again. By switching in this way, the components of the gas can be continuously separated.
Characteristics of CMS method
In activated carbon, the adsorption amount of gas is influenced by temperature, total gas pressure, partial pressure (concentration) of composition gas, adsorption speed, etc. Pressure swing adsorption (PSA) is a technique to swing pressure. The adsorption amount increases at high pressure and decreases at low pressure. Therefore, self-regeneration is possible by switching pressure. The basic flow of normal pressure regenerative PSA is shown in the following figure.
The raw material gas is pressurized once and then led to adsorption tower A filled with CMS. At that time, components with fast adsorption kinetics (e.g. O2) are adsorbed, while components with slower kinetics (e.g. N2) go through the adsorption tower A as a product gas.
Once the adsorbing capacity of tower A is full, the same step is repeated in tower B while desorption takes place in tower A. Switching cycles enables a continuous production of the desired gas.
CMS（Carbon Molecular Sieve）
Image of separating gas (adsorption and desorption) using CMS （Carbon Molecular Sieve) for PSA
CMS （Carbon Molecular Sieve) with precisely controlled activation and pore size makes it possible to separate gases with different adsorption rates.
Application examples
Separation of nitrogen (N 2) and oxygen
Separation of methane gas (CH 4) and carbon dioxide gas
Separation of hydrogen (H2) and other substances
Separation of propane gas and propylene
Various gas separation purification
Characteristics of Products
→As the world leading manufacturer of CMS, OGC provides high quality products for Pressure Swing Adsorption (PSA) applications
→Widely used for nitrogen generation up to 99.999% purity in a variety of industries
CMS are low-activated carbons presenting uniform and finely controlled pore size distribution on their surface, providing adsorption selectivity between different gases.
Pressure Swing Adsorption (PSA): A Technical Overview
Using CH4-PSA filled with carbon molecular sieves (CMS) to treat biogas and separate methane and carbon dioxide
After anaerobic fermentation of biomass, the biogas is extracted following desulfurization and desiloxanation using activated carbon (methane concentration in the biogas is 50-60%). The extracted biogas is then separated into methane and carbon dioxide using CH4-PSA filled with carbon molecular sieves (CMS). Furthermore, the methane concentration is purified to over 90%. The obtained high-purity methane is used for fuel cells and CNG (compressed natural gas).
Using H2-PSA filled with carbon molecular sieves (CMS) to treat a mixed gas and separate hydrogen and carbon dioxide
The extracted high-purity methane is reacted with steam (steam reforming) to reform it into a mixed gas of hydrogen and carbon dioxide. This mixed gas is separated into hydrogen and carbon dioxide using H2-PSA filled with carbon molecular sieves (CMS) to obtain high-purity hydrogen. High-purity hydrogen is used for fuel cells and hydrogen vehicles.
Case Study: Hydrogen Extraction Process Using Carbon Molecular Sieve (CMS)
Example of hydrogen extraction using sewage biogas as raw material
Using CH4-PSA and H2-PSA filled with carbon molecular sieves (CMS), hydrogen and methane are separated from biogas.
Anaerobic fermentation in a wastewater sludge treatment facility (digester) produces a mixed gas of methane and carbon dioxide. This mixed gas is purified using a desulfurization unit and a desiloxane unit. Next, methane and carbon dioxide are separated using CH4-PSA filled with CMS, and the purity of methane gas is further purified to 90% or more. Then, the high-purity methane is subjected to steam reforming, and hydrogen and carbon dioxide are separated using H2-PSA filled with CMS to extract high-purity hydrogen (hydrogen 90% or more).
Market share of Osaka Gas Chemical Group of CMS
Osaka Gas Chemical Group
Osaka Gas Chemicals Group is the largest in Japan and the world in terms of both sales and production capacity (as of April 2016). The production capacity and market share of CMS (Carbon Molecular Sieve) is No. 1 in the world (results in 2015).
World share of CMS production capacity (actual in 2015)
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