DEVELOPMENT OF A NOVEL PROCESS FOR THE SEPARATION OF NITROGEN FROM NATURAL GAS USING A NITROGEN SORBENT

NATURAL GAS PROVIDES AN INCREASINGLY IMPORTANT PORTION OF THE UNITED STATES' ENERGY SUPPLY. ESTIMATED U.S. GAS RESERVES ARE ABOUT 1000 TRILLION STANDARD CUBIC FEET (SCF)--OR ABOUT 1000 QUADS. UNFORTUNATELY, FULLY 25% OF KNOWN U.S. GAS RESERVES ARE CONTAMINATED WITH NITROGEN TO THE EXTENT THE GAS CANNOT BE USED WITHOUT PROCESSING TO REDUCE THE CONCENTRATION OF NITROGEN. NO TECHNOLOGY EXISTS TODAY FOR THE COST-EFFECTIVE REMOVAL OF NITROGEN FROM NATURAL GAS AT THE WELLHEAD. BEND RESEARCH PROPOSES TO DEVELOP AN ECONOMICAL, EFFICIENT PROCESS FOR PRODUCING PIPELINE-SPEC NATURAL GAS FROM N2-CONTAMINATED GAS AT THE WELLHEAD. IN THIS PROCESS, THE N2 WILL BE SEPARATED FROM THE NATURAL GAS VIA A NOVEL LIQUID ABSORBENT. THIS ABSORBENT WILL HAVE A HIGH AFFINITY FOR NITROGEN AND LITTLE OR NO AFFINITY FOR METHANE OR ANY OTHER HYDROCARBONS PRESENT. A GAS/LIQUID CONTACTOR WILL BE USED TO BRING THE N2-LADEN NATURAL GAS IN CONTACT WITH THE ABSORBENT UNDER CONDITIONS THAT FAVOR ABSORPTION OF NITROGEN (HIGH NITROGEN PARTIAL PRESSURE). THE ABSORBENT WILL BE PUMPED TO ANOTHER CONTACTOR THAT IS KEPT AT A STATE THAT WILL FAVOR DESORPTION OF THE NITROGEN (LOWER NITROGEN PARTIAL PRESSURE). THE PURIFIED NATURAL GAS WILL REMAIN AT WELLHEAD PRESSURE AND CAN BE ADDED TO THE PIPELINEWITHOUT FURTHER COMPRESSIONS. DURING THIS PHASE I PROOF-OF-CONCEPT PROGRAM WE WILL ATTEMPTTO DEMONSTRATE 1) REVERSIBLE N2 COMPLEXATION BY THE ABSORBENT UNDER THESE "PRESSURE SWING" CONDITIONS, 2) RATES OF N2 BINDING AND DISSOCIATION SUFFICIENT TO LEAD TO AN ECONOMICAL PROCESS, AND 3) SUFFICIENT N2/CH4 SELECTIVITY TO INDICATE THAT CH4 LOSSES IN THE ULTIMATE PROCESS WILL BE AT LOW, ACCEPTABLE LEVELS. PHASE I WILL ALSO RESULT IN AN ECONOMIC AND TECHNICAL ANALYSIS THAT WILL DICTATE TARGETSFOR A FOLLOW-ON PHASE II PROGRAM LARGELY AIMED AT FURTHER DEVELOPMENT OF N2-COMPLEXING COMPOUNDS AND THEIR SOLUTIONS. PHASE II WOULD CULMINATE IN A BENCH-SCALE DEMONSTRATION SUFFICIENT TO ATTRACT PRIVATE-SECTOR SUPPORT FOR PHASE III.