The Upstream Oil and Gas Industry is an energy intensive industry. The industry is required to consume significant amounts of energy to process raw gas and liquids to either a finished or semi-finished product of sales gas, LPG’s, sulphur and oil or condensate. This energy requirement is commonly referred to as the Production Energy Intensity (PEI). One specific area that is of common concern to many upstream operating companies is the energy consumption associated with immersion heaters. The energy often used to fire these heaters is high quality refined sales gas. In 1979 a study estimated that in Alberta line-heaters and treaters consumed 70 Bcf/A in fuel gas, which is equivalent to 8 billion BTU/hr, at a cost in excess of $320 million/A. A common problem with the immersion heaters is that they may have low fuel efficiencies between 30% and 60%. Compared to common boiler technology these heaters should be able to run at between 70 to 80% efficiency. Even when taking into consideration the cyclic nature of operation associated with many of the applications, these heaters currently waste in excess of 2 to 3 billion BTU/hr of fuel (1360 to 2040 e3m3/d gas) that could be conserved to generate added sales. At an average cost of $5/GJ this represents $100 to $150 million of lost revenues due to inefficient use of fuel gas. This also represents an associated 1.5 million additional tonnes of carbon dioxide being discharged into the atmosphere per year.
Often lower heater efficiencies are associated with high levels of oxygen or combustibles and high stack temperatures. These can result from poor burner performance and poor control of combustion air or improper configuration or the size of the fire-tube. Unlike steam or hot water boiler practices of efficiency calculations and guarantees, the efficiencies of immersion heaters are rarely considered during a typical specification, design, manufacturing, or operation cycle of the equipment.
Final Report Documents