Problems and Prospects of Natural Gas Transmission and Distribution in Nigeria

Abstract

ABSTRACT Natural gas as a raw material, is produced in large quantities in oil and gas wells in Nigeria. Although produced in large quantities, the lack of effective transmission and distribution systems results in a greater percentage of this energy source being flared off, thereby resulting in wastage of valuable and scarce foreign exchange for the country. In 1983 alone, of the total gas produced, 78.65% was flared, amounting to approximately 106.36 T kcal/year (1.241 GSCF/D). In an attempt to curtail this colossal wastage of energy and valuable raw material, the Federal Government of Nigeria passed a law on gas flaring and imposed a fine of thirty kobo (30 kobo per m3 in 1979 was equivalent to about 45 cents/m3) per cubic metre of gas flared. This yielded little or no result since the oil producing companies found it more convenient and economical to flare the produced gases. Based on the above premises, a pipeline network for natural gas distribution for Port Harcourt city was designed with the aid of Hewlet-Packard HP-85 computer. A static design model was used and optimization of the network was carried out on the main pipeline diameter such that no pressure or technological specification was violated. The distribution network was designed to have a capacity of 522 Mscf/D (14.62 Mm /D) based on an estimated gas supply/demand for thirty years in Port Harcourt city. The distribution pattern to the residential areas was based on population density of the city. The total length of the network was 16.6 miles (26.72 km). The maximum and minimum pressure specified at any point in the main pipeline were 300 (2067 kPa) and 100 psi (689 kPa) respectively. The design was also carried out within the compression ratio range of 1 to 1.6, and diameter of 40.64 to 96.52 cm (16 to 38 in) of the main pipeline. The design was performed for inlet pressures ranging from 150 to 200 psi (1033.5 to 1378 kPa).