Enhancing fired heater efficiency, reliability, and longevity A multi-layered approach, combining multiple, complementary technologies, enables a more integrated and effective method of optimising fired heaters
Larry Emch Integrated Global Services
F ired heaters are critical for most processes in oil refining and petrochemical processing, and are among the most energy-intensive assets within a facility. According to industry estimates, they are responsible for approximately 400 to 500 million tons of CO₂ emissions annually, with fuel efficiency typically ranging between 70% and 93%, depending on design, maintenance, and operational practices. Even 1-2% inefficiencies in fired heater performance can lead to millions of dollars in additional fuel costs and lost production capacity each year. In recent years, the drive toward operational excellence and regulatory compliance has prompted energy operators to seek comprehensive strategies to reduce emissions, decrease fuel consumption, and enhance asset reliability and longevity. These goals, although ambitious, are becoming increasingly achievable due to technological advancements in surface-engineered coatings, robotic cleaning, online proactive inspection, maintenance and repair methods. This article will first examine the broader context and technologies underpinning fired heater optimisation, and then present a detailed case study of a multi-phase, multi-year project at a large integrated refinery and petrochemical complex on the western coast of India. Through this case study, we observe how a layered, data-informed strategy can result in significant operational, environmental, and financial improvements. Figure 1 outlines a broader spectrum of CO₂ emissions reduction strategies, and this article will focus on process optimisation solutions and more specifically, ways to improve energy efficiency in the radiant and convection sections of fired heaters.
Understanding key inefficiencies in fired heaters Fired heaters are composed of a radiant section, where heat is transferred directly to process fluids via radiant energy, and a convection section, which recovers additional heat from flue gases. Both sections are susceptible to performance degradation over time due to fouling, oxidation, and refractory wear. Radiant section inefficiencies The radiant section operates by heating process fluids within alloy tubes using energy radiated from burners. Radiant section inefficiencies arise due to high operating temperatures, which cause steel alloy process tubes to oxidise and develop scale layers (see Figure 2 ). This scaling, even in 9Cr-1Mo materials above 500°C, will occur, producing layers of scale which significantly reduce heat transfer efficiency by insulating the tube surfaces. To compensate, operators increase firing rates, resulting in higher flue gas and bridgewall temperatures, elevated CO₂ and NOx emissions, and an increased risk of tube overheating and damage. Oxidation and scale formation results in metal loss and tube wall thinning, up to 0.25 mm/year, which is a major factor in reducing tube life. Carburisation An industry trend to operate fired heaters more efficiently, at lower excess oxygen levels, to save fuel and reduce CO₂ emissions has increased the potential for carburisation of external surfaces of radiant section tubes.
Refining India
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