Why Use Economiser in Boiler

An economiser is a critical heat exchanger device installed in boiler systems to preheat the feed water using waste heat from flue gases before it enters the boiler drum. This process significantly enhances the overall thermal efficiency of the boiler plant by reducing fuel consumption and lowering operational costs. By capturing and repurposing energy that would otherwise be expelled into the atmosphere, economisers directly contribute to substantial energy savings and a reduced carbon footprint. The primary reason for their use is the remarkable improvement in efficiency; industry data and case studies consistently show that installing an economiser can boost boiler efficiency by 5% to 10%. For a large industrial boiler consuming heavy fuel oil, this can translate to annual fuel savings of thousands of dollars, with a typical payback period of less than two years. Furthermore, by lowering the temperature of exhaust flue gases, economisers help reduce the thermal load on downstream pollution control equipment, such as scrubbers or baghouses.

The operational benefits of integrating an economiser into a boiler system are extensive and well-documented through real-world performance metrics. For instance, a comprehensive study by the U.S. Department of Energy on industrial boiler systems demonstrated that for every 40°F (22°C) reduction in flue gas temperature achieved by an economiser, boiler efficiency increases by approximately 1%. In practical terms, this means a system reducing flue gas temperature from 450°F to 250°F can achieve around a 5% efficiency gain. This is not theoretical; data from manufacturers like Cleaver-Brooks and Thermax shows their economiser installations routinely deliver fuel savings of 4% to 8% across various industries, including chemical processing, power generation, and food production. The financial impact is undeniable. A large textile mill reporting annual fuel costs of $1.5 million could save between $60,000 and $120,000 per year. Beyond direct fuel savings, the preheated feed water reduces thermal shock within the boiler, minimizing thermal stress on the pressure vessel and extending the equipment's operational lifespan, which defers capital expenditure on replacements. From an environmental compliance perspective, lower flue gas temperatures also often mean lower NOx emissions, helping plants meet stringent regulatory standards. The combination of hard data on efficiency gains, proven cost savings, enhanced equipment durability, and environmental benefits makes the economiser an indispensable component for any modern, cost-conscious, and sustainable boiler operation.