News Center
Zeolite Encyclopedia-Molecular Sieve 13X
1.1Basic skeleton structure
The framework of FAU type molecular sieve is composed of 6.5Å (Å is angstrom, 1Å = 0.1 nm) cubic sodalite cage. These sodalite cages are the basic units of their structure, held together by six-membered oxygen rings in tetrahedral form.
Multiple soalite cages are connected in a specific way to form a large cavity with a diameter of about 1.25 nanometers, also known as a supercage. This large cavity structure provides a large space for adsorption and diffusion of molecules.
1.2 Way of connection
1.2.1 Six-atom prism connection:
The six-atom prism acts as a connection between the sodalite units, making the entire structure more stable and orderly.
1.2.2 Window connection: These cages are connected to each other in tetrahedral form through with a window diameter of about 7.5Å, ensuring the transport and diffusion channels of molecules within the molecular sieve.
Unit-Cell composition: Each cell contains 192 tetrahedrons TO₄ (T for Si, Al, etc.). When Si atoms are replaced by other atoms (such as Al atoms), the crystal structure becomes negatively charged and requires metal cations (such as Na +, Ca² +, K +, etc.) to balance out, rendering the whole system electrically neutral.
1.2.3 Silica-aluminum ratio and classification: According to the different mole ratio of silica-aluminum in FAU zeolite material, it can be divided into X zeolite (Si/Al = 1~1.5) and Y zeolite. In the case of all-silicon zeolites, a unit cell is 576 atoms (O₃₈₄, Si₁₉₂).
2.Applications
2.1 Removal of H2S
The main components of natural gas are methane and other alkanes, but natural gas often contains impurities such as H2S, CO2 and H2O. During transportation, H2S and H2O can generate acidic liquids to corrode pipelines and valves. In addition, H2S will generate polluting gases such as SO2 during combustion. The adsorption effect of 13X molecular sieve on H2S and CO2 is obviously greater than that of hydrocarbons, so molecular sieve 13X has been widely used in the process of natural gas exhaust desulfurization.
2.2 Hydrogen energy and proton exchange membrane fuel cells
Molecular sieve 13X also have the potential to be used in hydrogen energy and proton exchange membrane fuel cells. At present, hydrogen production from fossil energy and industrial by-product hydrogen still occupy an important proportion of hydrogen energy production capacity, and sulfur elements from fossil energy sources such as coal, oil and natural gas will exist in the form of H2S in the hydrogen energy production process. Compared with silica gel, activated carbon and other porous materials, molecular sieve 13X showed excellent H2S adsorption. The adsorption of H2S by molecular sieve 13X is a physical adsorption process, and the molecular sieve can be regenerated by rising temperature after adsorption. Compared with traditional chemical treatment processes, the use of molecular sieve 13X as a physical adsorbent helps to reduce energy consumption and pollution in the adsorption process. In addition, proton fuel exchange membrane cells also put forward higher requirements for the purification of hydrogen energy, because even trace amounts of H2S in hydrogen will have a toxic effect on battery catalysts such as Pt/C electrodes, and by improving the adsorption performance of molecular sieve 13X or modified molecular sieve 13X for H2S, it also provides a solution to the challenges brought by hydrogen purification.
2.3 Removal of CO2
The process of using molecular sieve 13X to capture CO2 at normal temperature has been successfully applied commercially, involving a wide range of industries. In the natural gas industry, molecular sieve 13X can adsorb CO2 from natural gas feedstock to improve the purity of natural gas to meet fuel use standards. In the air separation industry, it is necessary to remove impurities such as water, CO2 and some hydrocarbons in the air separation device to obtain high-purity nitrogen, oxygen and other gases. Molecular sieve 13X can effectively adsorb CO2 in the air, provide pure air raw materials for the air separation process, and ensure the efficiency and purity of subsequent gas separation. It can be used as an effective adsorbent for CO2 adsorption and capture in industrial waste gas, and provide technical support for CO2 emission reduction and recycling. For example, in the waste gas treatment of some thermal power plants, cement plants and other industrial enterprises, molecular sieve 13X can be used to adsorb CO2 and reduce the CO2 content in the waste gas.
2.4 Oxygen industry
Using the polarity difference between nitrogen and oxygen and the difference in diffusion rate, molecular sieve 13X can be used for nitrogen and oxygen separation. Under pressurized conditions, molecular sieve 13X can preferentially adsorb nitrogen to enrich oxygen. During decompression, nitrogen adsorbed on the molecular sieve 13X is released, so the molecular sieve can be recycled to reduce operating costs. On this basis, the modified molecular sieve Li-13X obtained by ion exchange can significantly improve the adsorption performance of nitrogen and further improve the purity of oxygen, and can be applied to the medical oxygen industry.
Dalian Chuangge Technology Co., Ltd
Richard Han
Doris Zhou
Headquater: 9th Floor, Century Classic Building, No.10, Xinghai Square, Shahekou District, Dalian City, Liaoning Province
Copyright: Dalian Chuangge Technology Co., Ltd. Business License Privacy Policy
