Hybrid hydrogen - carbon dioxide separation systems. Presentation of the HY2SEPS project
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Polityka Energetyczna – Energy Policy Journal 2006;9(Zeszyt specjalny 1):657–669
Increased CO2 emissions in the atmosphere are the result of human activities related to energy production from fossil fuels. Fossil fuels are expected to be the main source of energy for the next decades, and the main source of CO2 emissions associated with human activity. To meet future regulations and standards, sustainable energy systems based on fossil fuels will require a significant reduction of emitted greenhouse gases and other pollutants. According to the 4/2004 European Environmental Agency report, CO2 emissions from fossil fuels account to 78% of the total EU greenhouse gases emissions. The reduction of CO2 emissions is included in the workprogramme of Priority 6.1. The case examined in the "Hybrid hydrogen - carbon dioxide separation systems" (HY2SEPS) project is the pre-combustion CO2 capture, which is one of the four strategically important research areas of the thematic priority 6.1. The main goal of the HY2SEPS project is the development of a hybrid membrane/ pressure swing adsorption (PSA) H2/CO2 separation process, which will be a part of a fossil fuel de-carbonization process used for the pre-combustion CO2 capture. Methane steam reforming is currently the major route for hydrogen production and will be employed as a model case. High purity hydrogen (99.99%) is usually recovered from the reformate by using a PSA process. A typical PSA waste gas stream (CO2~55%, H2~35%, CH4 & CO~ 15%) is not usually recycled since it has to be recompressed to the PSA feed pressure for recovering only a small fraction of the recycled hydrogen. Furthermore, it cannot be used for CO2 sequestration since it contains significant amounts of H2 and CH4. A hybrid process is expected to combine the high throughput and H2 product purity of a PSA process with the lower operating costs of a membrane process. It is expected to enhance the overall H2 recovery and provide an H2-free CO2 stream ready for capture and sequestration. Below are listed main task carried out within the HY2SEPS project. 1. Material research related to existing and new membrane and sorbent materials. 2. Process design and integration. 3. Evaluation of hybrid process sustainability using life cycle analysis. 4. Component design. Preliminary experimental studies for the adsorption equilibria and kinetics of the mass transport of CO2 and CH4 on the first membrane material were performed. For the sample scraped off the active layer of the membrane, equilibrium and kinetic experiments were done over the pressure range 0-2 bar and temperatures between 20 and 90 oC. It is concluded that the equilibrium capacities for methane are by an order of magnitude lower than those for carbon dioxide (Figs 5 and 6). In the case of diffusional time constants the appropriate values for methane are 2-3 times higher than those for carbon dioxide (Tab.1).
Hybrydowe układy do rozdziału mieszanin wodoru i dwutlenku węgla. Prezentacja projektu UE HY2SEPS
ograniczanie emisji CO2, wytwarzanie wodoru, proces hybrydowy, adsorpcja zmiennociśnieniowa, procesy membranowe
Ograniczanie emisji gazów cieplarnianych, zwłaszcza CO2 jest obecnie jednym z najpoważniejszych wyzwań podejmowanych przez instytucje naukowe, rządy państw i organizacje przemysłowe na całym świecie. Inicjowanie działań zmierzających do rozwiązania tego problemu stało się m.in. celem priorytetu tematycznego 6.1 (Zrównoważone Systemy Energetyczne) w ramach 6. Programu Ramowego UE. W niniejszej pracy przedstawiono projekt UE HY2SEPS jako przykład działań podejmowanych w obszarze priorytetu tematycznego 6.1. Omówiono cele projektu oraz planowane sposoby ich realizacji. Zaprezentowano także wstępne wyniki badań właściwości separacyjnych pierwszego materiału membranowego, planowanego do wykorzystania w układzie hybrydowym.
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