Real-Time Synthetic Conversion of the Entire Flared Associated Natural Gas Stream to Liquefied Petroleum Gas (LPG)

Abstract

About 1,000 scf of gas is produced with every barrel of oil produced in Nigeria which implies that about 2.8 billion scf of associated gas is produced daily, based on the OPEC allowed 2.8 million barrels per day (bpd). At present, about 50% of the associated stranded natural gas produced in Nigeria is still being flared, that is 1.4 billion scf (30,960.974 tons or 30,960,974 kg of LPG equivalent on conversion)daily. On the other hand, Nigeria's annual consumption of LPG is expected to be 2.0 million metric tons this 2018 while 11.3 million metric tons (30,960.974 x365 tons =11,300,755.51 tons or 11,300,755,510 kg) can be produced annually from the entire flared gas.  The major components of LPG (propane and butanes) hydrocarbons are gaseous at normal atmospheric temperature (20⁰C) and pressure (14.7psia, 0psig), but are readily liquefied through pressurization (by  compression) at relatively moderate pressures less than 200psig at room temperature (25⁰C), leading to volume reduction from 270 scf  of gas to 1 cubic feet  of liquid, which implies that the flared 1.4 billion scf in gaseous form will reduce to approximately 5.2 million cubic feet in liquid form. The investigation on the real-time Synthetic Conversion of the Entire Flared Association Gas Stream to liquefied Petroleum Gas (LPG) is focused on the use of customized skid mounted mini gas liquefaction plants aimed at cracking the C₅+ fractions to the lighter molecules of C₃ and C₄ as well as steam reforming the C₁ and C₂ fractions to the heavier molecules of C₃ and C₄. The approach is based on the fact that it is technically feasible to synthesize almost any hydrocarbon from any other using chemical transformation operations to change the proportions of the hydrocarbons contents. The actual hydrocarbons percentage in typical flare line is 97.61%, and for the 20 million scfd flare stream it is equivalent to 19,522,000 scfd, that is 442.300 tons or 442,300 kg of LPG daily. Assuming that 20 % of the chemical energy of the entire flare stream is released as heat energy in the process, it implies that 80 % of the hydrocarbon component of the flare stream is available for conversion to LPG daily i.e. (442,300 x 0.8) = 353,840 kg. Annually it is equivalent to 442.300 x 365 tons (161,439.5 tons or 161,439,500 kg). Currently there are about 350 bottling plants while to saturate the market with LPG the country needs about 2000 bottling plants. The LPG producible from the countries flared stranded gas, will be is sufficient to saturate the Nigerian market with LPG, drastically reducing the retail price of LPG that is presently hinged on the NLNG international market fundamentals as well as improve on Nigeria's per capita usage of LPG which is currently ranked the lowest in Sub-Saharan Africa. LPG is a group of flammable hydrocarbon gases that are commonly used as fuel in heating appliance, cooking equipment, vehicles, as well as for refrigerant, aerosol propellants and petrochemical feedstock. Although each of the specifications of LPG (commercial propane, commercial butane, is o butane, mixture of propane- butane) have some areas of preference, based on their different physical properties, any device that is suitable for any of the LPG category, would also be suitable for the others, primarily by adjustments on the maximum flow rate, to adopt to the maximum output of the device. Due to the strong quest for cleaner energy and numerous petrochemical/chemical products from methane, ethane, propane and butanes, the world is presently witnessing rapid transition from the "gasoline age" to what might be called "LPG/methane age or methane economy".