Descripción del proyecto
THIS SUB-PROJECT IS PART OF A COORDINATE PROJECT DIRECTED TO THE PRODUCTION OF BIOENERGY FROM WASTEWATER TREATMENT PLANTS (WWTP). IN PARTICULAR, THIS SUB-PROJECT IS FOCUSED IN THE PRODUCTION OF GREEN HYDROGEN BY DRY REFORMING OF A BIOGAS STREAM AND ITS FURTHER PURIFICATION BY WATER GAS SHIFT REACTION COMBINED WITH THE SIMULTANEOUS CAPTURE OF THE PRODUCED CO2. THE USE OF HYDROGEN AS ENERGY VECTOR FOR THE NEXT YEARS HAVE BEEN STRONGLY PURSUED BY THE EU COMMISSION IN THE SO-CALLED HYDROGEN ECONOMY STRATEGY, AND SPAIN IN ITS RECENTLY PUBLISHED HYDROGEN ROADMAP. THUS, THE INCREASING DEMAND OF H2 PREDICTED FOR THE NEXT YEARS COUPLED WITH THE GLOBAL CONCERN ABOUT CLIMATE CHANGE AND CO2 EMISSION, PLACED THIS SUBPROJECT IN A STRATEGIC POSITION IN THE FRAME OF THE ENERGY TRANSITION. THE HIGH LEVELS OF CO2 (45-75%) AND CH4 (55-75%) IN THE BIOGAS ENABLE ITS CONVERSION TO SYNTHESIS GAS (CO AND H2) BY DRY REFORMING, AVOIDING THE HIGH COST OF THE PURIFICATION PROCESS TO SEPARATE CO2 FROM CH4. IN ADDITION THE CO AND H2 OBTAINED FROM THE DRY REFORMING, CAN BE FURTHER PURIFIED INTO H2 AND CO2 BY A WATER GAS SHIFT (WGS) REACTION COMBINED WITH CO2 CAPTURE, WHEREAS THE CAPTURED CO2 CAN BE RECYCLED IN THE DRY REFORMING UNIT. WHILE BOTH DRY REFORMING AND WGS ARE MATURE TECHNOLOGIES IN SOME MATTER, CATALYST DESIGN IS THE BOTTLENECK OF THESE PROCESSES, BEING LOW PROCESS EFFICIENCY, CATALYST DEACTIVATION BY COKE FORMATION AND CATALYST POISONING BY REMAINED IMPURITIES (ESPECIALLY H2S) IN THE UPGRADE BIOGAS STREAM, THE MAIN DRAWBACKS. IN THIS DIRECTION, THE CORE OF THIS SUB-PROJECT IS DIRECTED TO A RATIONAL DESIGN OF NEW CATALYSTS WITH CONTROLLED ACTIVE SITES. INITIAL STUDIES WILL BE DONE USING SYNTHETIC BIOGAS ALLOWING A FAST SCREENING OF CATALYSTS AND, IN A SECOND STEP, A REAL BIOGAS STREAM (DELIVERED BY UMA GROUP AFTER BIOGAS UPGRADING) WILL BE USED ON THE MOST PROMISING CATALYSTS IN ORDER TO EXPLORE THE STABILITY OF THE CATALYST AGAINST CONTAMINANTS SUCH AS H2S AND NH3 PRESENT IN REAL BIOGAS. FUNDAMENTAL STUDIES USING OPERANDO SPECTROSCOPIC TOOLS WILL CONTRIBUTE TO UNRAVEL THE KEY ASPECTS IN ACTIVE SITES AND ITS INTERACTION WITH THE REACTANTS AND INTERMEDIATE SPECIES, ENABLING CATALYST OPTIMIZATION. THUS, IN PARTICULAR, IN THE DRY REFORMING OF METHANE, THE C-C FORMATION RATE (I.E. COKE) VERSUS C-O (I.E. CO) WILL BE CONTROLLED BY ADJUSTING THE PARTICLE SIZE OF NICKEL BASED CATALYSTS, FROM THE NANOSCALE DOWN TO THE ATOMIC SCALE. ADDITIONAL PARAMETERS SUCH AS METAL-SUPPORT INTERACTION FOR HIGH CATALYST STABILITY, SURFACE VACANCIES AND ACID/BASE PROPERTIES AND THE ADDITION OF SPECIFIC PROMOTERS FOR CATALYST EFFICIENCY AND SULFUR TOLERANCE, WILL BE STUDIED. IN THE WGS AND CO2 CAPTURE REACTION, BIFUNCTIONAL CATALYSTS WILL BE DEVELOPED THAT INCORPORATE A CATALYTIC FUNCTION (CAPABLE OF CARRYING OUT THE WGS REACTION AT INTERMEDIATE TEMPERATURES) AND AN ADSORBENT (CAPABLE OF RETAINING THE CO2 PRODUCED). THE ADDITION OF SPECIFIC PROMOTERS FOR CATALYSTS STABILITY AND SULFUR TOLERANCE WILL BE CONSIDERED.IN CONCLUSION, THE GENERAL AND SPECIFIC OBJECTIVES OF THIS SUB-PROJECT ARE THE VALORIZATION OF BIOGAS, A RENEWABLE RAW MATERIAL DERIVED FROM BIOMASS, TO PRODUCE GREEN HYDROGEN. IN THIS DIRECTION, EFFICIENT AND STABILE CATALYSTS WITH HIGH POTENTIAL TO BE SUCCESSFULLY APPLIED IN THE GREEN HYDROGEN PRODUCTION FROM A REAL BIOGAS BY DRY REFORMING AND SUBSEQUENT SORPTION ENHANCE WGS WILL BE DEVELOPED.