Monetizing the Flared Associated Natural Gas in Real-Time Via Synthetic Fuels Production

Abstract

The basic organic compound which serve as raw materials for the preparation of the many specific synthetic compounds are obtained from four sources: plant live, wastes, coal tar, petroleum (crude oil and natural gas). Wood was the first of man's fuel and is still the primary energy source in most parts of the world. At the onset of the industrial revolution, charcoal from wood was replaced by coke from coal. Subsequently, the development of the internal-combustion engine and the automobile created a vast new market for gasoline product made from crude oil; kerosene use for lighting and heating oil began to replace coal in many energy markets. Thus, the industrial revolution lead to the change from the use of hand tools, using human mechanical energy to machine and power tools, which allowed the conversion of energy in falling water to mechanical energy (water wheels) or conversion of chemical energy in wood or coal to mechanical energy (steam engine) for industrial processes.  Synthetic fuels are liquid or gaseous fuels extracted or fabricated from solid earth materials that are rich in hydrocarbons, such asbiomass (plants and plant-derived substance e.g., waste), coal, oil shale, tar sands, natural gas instead of refining crude oil. This paper reviewed the development of the GTL process technology from its recognition in 1902, to the evolving micro-channel technology. By 1953, Sasol of South Africa, was using natural gas to produce 30,000 bbl/d (4800 m³/d) synthetic fuels; while in Nigeria, flaring of associated stranded natural gas commenced in 1956 with the first successful well drilled at Oloibiri: Until 1984, the country flared virtually 100% of all the produced associated stranded natural gas. It reduced to 70% in 1999, and to, between 43-52 % in 2004, about where it remains up to date. Meanwhile, Nigeria's only GTL Project, by Chevron Nigeria Limited (CNL), which started with pre-feasibility study in 1998, contracted in 2005 with 34,000 bpd capacity at Escravos is still under construction today. On the other hand, the premier oil refinery in Nigeria was built and commissioned in 1965 with maximum capacity of 60,000 bpd, while the other three refineries are built at: Warri in 1978 with capacity 125,000 bpd; Kaduna in 1980 with 110,000 bpd capacity; and Port Harcourt in 1985 with 150,000 bpd capacity. For well over 20 years now, Nigeria imports more than 75% petrol products for transportation, because all the refineries either operate below 5% capacity or are fully short down (non-operational).  Since it is technically feasible to synthesize almost any hydrocarbon from any other, this work is aimed at establishing the daily quantity of synfuels obtainable from any gas flare line give the composition and flow rate. The study obtained 1,414.88 barrels (equivalent to 59,424.96 gallons or 226,240 litres) of synfuels plus 13MW electric power daily from 20 MM scfd flare line. This takes advantage of the fact that the size of GTL plants varies from small (5 to 15,000 bpd) to large (>50,000 bpd). Thus, no matter the quantity of gas being flared from a particular line, there is a plant size design that can produce synfuels, generate electricity from waste heat, plus water and other petrochemicals/ chemicals. End products are determined by the length of the hydrocarbon chain which, in turn, is determined by catalyst selectivity and reaction conditions (temperature, pressure and residence time). In general, the product range include the light hydrocarbon (C₁ and C₂), LPG (C₃ –C₄), naphtha (C₅ –C₁₂), kerosene-diesel fuel (C₁₃ – C₂₂), low-molecular weight wax (C₂₃ –C₃₂), linear alpha olefins et cetera.  Synfuels are cleaner than those produced via petroleum distillation. With virtually zero aromatics, sulfur, and high Octane/cetane numbers they are used to upgrade conventional gasoil by blending it with GTL gasoil.