Synthesis of PET-Magnesium Oxide-Chitosan Nanocomposite Membranes for the Dehydration of Natural Gas

Flat thin-film magnesium oxide-chitosan nanocomposite membranes were synthesized with polyethylene terephthalate (PET) and employed for natural gas dehydration. The water vapor permeation was most pronounced with a nanocomposite membrane doped with 0.9 g MgO nanoparticles (NP) as a result of a significant upsurge in the permeability of water vapor in the membrane (0.87). With the increase in MgO NP, large macro-voids are created, substratum pore size, and thickness together with the water vapor permeation were upsurged. The dehydration of natural gas performance of magnesium oxide-chitosan nanocomposite membranes synthesized with PET was enhanced with the increase in MgO NP embedded in the membrane. Though water vapor permeation was restricted by the polyester non-woven material used as a support for the nano composite membranes, as the three membranes did not reach the permeation coefficient of 1. However, the permeation coefficient increased with an increased MgO NP, with three mambrane samples (M1, M2 and M3) having permeation coefficient of 0.763, 0.77 and 0.87 respectively. The gas reduced with an increase MgO NP, with M1, M2 and M3 having 3.46×10−2, 3.17×10−2 and 3.88×10−3 kg/m3 respectively. From the adsorption study, the discrepancy observed between CH4 and vapor with isotherm models was ascribed to the different adsorption behavior of CH4 and vapor on the membrane-active area. The cost of making the membrane cannot be considered as a terminal criterion because most of the cost-effective option is not always the optimum one. The membranes confirmed their suitability for the dehydration of natural gas

GAS-TO-WIRE FOR UTILIZATION OF STRANDED ASSOCIATED GASES IN NIGER DELTA

Gas-to-wire system has been a promising technology to convert stranded gas to electricity in remote oilfield locations where there is no infrastructure to monetize the gas. The research work was carried out to design an optimized process system which includes process simulations, equipment sizing and cost estimations. The basis for the work is a 5.1 MMscfd (million standard cubic feet per day) of associated gas from an active gas flaring site in Niger Delta Nigeria. The inlet gas has a temperature of 35oC, pressure of 66.5 barg, water content of 63.13 lb/MMSCF, water dew point of 40 oC and 3.97% molar concentration of CO2. The gas-to-wire process route selected comprises acid gas removal, gas dehydration and a combined cycle system. ASPEN HYSYS V10 was used to produce a base case process simulation and sensitivity analyses to arrive at optimal process operating conditions which include for the acid gas removal unit: 8.70 m3/hr of 28% weight strength of Diethanolamine (DEA) in aqueous solution, lean loading of 0.00757 (mol/mol), rich loading of 0.4310 (mol/mol), reboiler duty of 1.002 (lb Steam/Gallon Rich Amine) and 20number of absorber trays with 33% efficiency to obtain a treating gas specification of 15ppm of CO2. For gas dehydration, 0.90 kg/hr recirculation rate of Triethylene glycol (99.8 % by mass) with 0.033 MMscfd of stripping gas injected into the reboiler was the optimal condition to dehydrate the wet from the amine gas treating unit gas to 0.7 lb/MMSCF water content and dew point of -7 oC using 4 absorber trays with 25% efficiency when the lean amine temperature is 40 oC. The combined cycle efficiency simulated has a net power of 27.5 MW and total thermal efficiency of 42%. The research work contributed process design data that can be used to make technical and investment decisions