Peak Shaving Plant at General Rodriguez (Buenos Aires, Argentina) and its role to fulfill natural gas demand
Authors: Mingot Antoni Peris , Cristiani Horacio 
Published: December 2007

This paper addresses the problems and management tools of the distribution system operated by Gas Natural BAN within the global Argentinean gas structure, and justify the convenience of having a Liquefied Natural Gas Plant, i.e. Peak Shaving Plant in the surroundings of Buenos Aires where happens to he the largest concentration of natural gas consumers in the country. This Plant is a technical alternative to fulfill uncovered demand during winter and besides results to he efficient and competitive when compared with the option of incrementing the transportation capacity of the main pipelines.

The paper details the process followed when designing and building the Peak Shaving Plant, the design basis and philosophy, its main features and also the main characteristics of the commissioning and operation.

Introduction

LNG Peak Shaving facilities are being provided in Argentina by Gas Natural BAN to assist in the efficient management of their natural gas supply system.

The productive gas reservoirs are located in the North West, Middle West and South of the country and hence far from the areas of maximum consumption. There are no facilities for intermediate storage of gas and the gas production system is non-regulated.

Gas Natural BAN is the distribution company that provides a gas supply to 30 districts around Buenos Aires with 1,000,000 domestic-commercial and 1,100 industrial customers.

The gas demands in Gas Natural BAN's distribution area varies from a maximum of 15 MSm3/day during the winter peak, to a minimum of 4 MSm3/day during summer. With no base load utilisation, the gas consumption depends mainly on the climate.

The system above mentioned presents a problematic situation with two important items to solve.

In one hand, the unsatisfied demand basically centered on the industrial customers with uninterruptibles contracts, and in the other one the economical impact that implies the management of a system in which the utilization factor of the transport capacity contracted is low, and the annual cost is of US $6,900,000 per million of m3 contracted.

Careful management of the gas supply system is required to ensure economic utilization and to minimize any disruption in gas supply to uninterruptable customers. Among the Gas Management "tools" considered, Gas Natural BAN has installed an LNG Peak Shaving Plant at General Rodriguez, in order to provide an adequate supply of natural gas periods of high demands, and in order to obtain the following objectives: - Improve the quality of the services to the customers.–Achieve the best of the management, decreasing the costs from and adequate utilization coefficient of the transport capacity contracted.

Location of the Plant

The Plant is located in a district 70 km North West from Buenos Aires City, called General Rodriguez. A map indicating the plant location is illustrated in Figure 1. The LNG plant site occupies an area of 11 hectares.

This site was selected following environmental and safety studies. The major factors which influenced site selection were as follows:–Large available plot area, which satisfied required safety distances and allowed for future expansion.–A rural location adjacent to a light industrial area.–Minimizes the environmental impact on the vicinity.–Adjacent to the main gas feed pipeline and the Gas Natural BAN distribution system.

Design Basis

Natural gas, supplied at a pressure in the range 20-60 bar, is liquefied over a period of 260 days per year at a rate of 101,000 Sm3/day. The feed gas comes from different sources and can contain up to 2 mol percent nitrogen, 2 mol percent carbon dioxide and 0.12 mol percent of hexane and heavier hydrocarbons. LNG product is routed to a 41,200 m3 storage tank.