'H2 separation is the most mature market for gas membrane separation technology. Hydrogen separation membrane + pressure swing adsorption combined process is the most suitable mode for H2 separation. With energy saving and consumption reduction, VOCs removal and CO2 emission reduction and other aspects have been continuously improved. , There will be more kinds of gas separation membrane products and processes applied in the petrochemical industry. 'The Secretary of the China Membrane Industry Association Petroleum and Chemical Membrane Technology Application Committee, Secretary-General Yan Yanzhai, briefed reporters on the development of gas separation membrane technology. .
'In the gas membrane separation technology, hydrogen separation membrane technology occupies a large proportion, is also the earliest development and application, the most mature gas membrane separation technology.' Party Yanzhai said that the advantages and disadvantages of hydrogen separation membrane are obvious, The general statement is that 'the concentrate is not purified'. Specifically, since the hydrogen separation membrane uses different gas molecules to achieve separation and recovery in the membrane, the yield of H2 is high, about 91%. The purity is low, the yield is not stable, and it is also affected by the change of feed composition.
In the actual application process, a hydrogen separation membrane and pressure swing adsorption (PSA) combination process is generally used. The hydrogen separation membrane is used to first increase the pressure-reduced dry gas in the refinery from 20% to 30% to 60% to 70%. After that, it is then purified using pressure swing adsorption technology. The combination of multiple hydrogen-rich gases generated in the oil refining process not only achieves the purpose of continuous gas separation, but also greatly improves the economics of gas separation and reduces the process H2 system. Take costs, while reducing CO2 emissions. ' Party Yanzhai said.
He introduced to reporters the example of PetroChina Dalian Petrochemical Corporation's recycling of hydrogen-rich resources to obtain considerable economic benefits. 'Dalian Petrochemical's hydrogen-rich resources include more than 2.2 million tons of reformed PSA desorption gas per year, with an annual output of 80 Ten thousand tons of diesel hydrodesulfurization gas and 4.2 million tons of light hydrocarbon recovery gas will produce hydrogen-rich gas. Dalian Petrochemical has implemented a hydrogen-rich recovery and reform project, using a hydrogen separation membrane and PSA combination process to convert these hydrogen-rich gases. After H2 recovery, it is used as process hydrogen. The reconstruction project has invested 100 million yuan, and the cost recovery period is only half a year. ' Party Yanzhai said.
After the project was implemented, not only the existing 100,000 Nm3/h hydrogen plant was shut down, but also achieved 170,000 Nm3/h of flue gas emission reduction. At the same time, the recovery of H2 also reduced the concentration of fuel gas and hydrogen, and the fuel heating furnace was operated. More stable; hydrogen-rich recovery unit put into operation also makes hydrogen changes quickly react to the hydrogen network, so that hydrogen network pressure control more stable.
'Our country's refining capacity is about 300 million tons / year, from desulfurization process to the production of diesel, gasoline, lubricants and other products are inseparable from hydrogenation. Preliminary calculations, China's oil refining industry needs about 15 billion to 200 billion m3H2 a year, if All coal-fired hydrogen plants will produce about 10 million tons of CO2, which will put a lot of pressure on China's carbon emission reduction. Therefore, refining companies should make full use of hydrogen-rich resources and choose according to their own conditions. Adapted hydrogen separation membrane + PSA combination process to demonstrate, transform. ' Party Yan Zhai said.
In addition, Dang Yanzhai also stated that the energy consumption of nitrogen from the air separation system is also very large. If the N2 is first enriched to 95% to 97% after the gas separation membrane is used for air separation, the air separation energy consumption can be reduced. Similarly, this idea can also be used in the preparation of oxygen-enriched gas.
In addition to hydrogen separation membranes, organic vapor membranes currently have some applications in the VOCs removal and organic monomer recovery processes in the petrochemical industry.
Dang Yanzhai stated that the current application of organic vapor membranes faces two major problems in the removal of VOCs: First, the problem of declining removal efficiency due to water-condensing gas; and second, the short-term gas flow exceeding the design load. The problem of degrading the removal effect. 'Advancing the application of organic vapor membranes in the field of VOCs removal must solve these two problems.' Party Yanzhai said.
He also pointed out that in addition to hydrogen separation membranes and organic vapor membranes, the requirements for removal of VOCs and reduction of CO2 emissions are increasing along with energy conservation and consumption reduction, and other types of gas separation membranes also have room for development in the petrochemical industry. H2S/CH4 separation membrane, higher performance O2/N2 separation membrane, CO2/N2 separation membrane for carbon capture, synthesis gas purification and CO2/H2 separation membrane used in IGCC power plant, and better olefin/alkanes Separation membranes, these are also potential development directions for gas separation membrane technology.