Increasing boiler efficiency is one of the simplest methods for a business to cut running costs. Looking at how frequently you completed boiler maintenance and how powerful your boiler is excellently minimized your expenses.
Before we can discuss efficiency techniques, we must first understand boiler efficiency. The stack or boiler water is where the preponderance of the heat in your boiler is dissipated. The goal is to establish circumstances that produce the least quantity of flue gas at the lowest temperature conceivable. As a result, the boiler’s efficiency improves.
Reduce Extra Air
Examining how surplus air levels are handled is one of the first things to think about when trying to enhance boiler efficiency. Boiler efficiency may be boosted by 1% for every 15% decrease of surplus air, according to a common rule of thumb.
The boiler’s burning efficiency will be maximized and heat loss up the stack will be minimized with a correctly built O2 trim system. To keep extra air at optimum levels, make sure the boiler control systems are operating correctly and have the boiler’s burner re-tuned regularly by a certified boiler/burner expert.
Economizer Should Be Installed
Even after passing thru the boiler, usable amounts of energy are still present in the flue gases in many boilers. Economizers are meant to catch and transmit the flue gas waste heat to warm the incoming boiler feedwater.
Extended-surface economizers are intended to optimize heat recovery and may lower the temperature of flue gas exit stacks to as low as 121°. Boiler efficiency improves by 1% for every 22°C drop in flue gas temperature.
Employ a Condensing Economizer
By condensing flue gas water vapor, condensing economizers are able to collect both latent and sensible heat. The flue gas output stack temperature may be reduced to as far as 100°F (38°C) with these devices. Determine how the condensed water from the exhaust gases will be discharged before installing a condensing economizer.
The low-grade heat generated cannot be utilized by the boiler system, unlike a normal feedwater economizer. For this to be a cost-effective alternative, a facility must have a steady gentle heat need.
Adopt SCR System (Selective Catalytic Reduction)
An SCR system with a typical no flue gas recirculation (FGR) low-excess air burner can utilize significantly less fan horsepower than a strong FGR, high excess air extremely low NOXX burner for purposes required ultra-low NOXX operation.
An ultra-low NOXX burner necessitates a much bigger fan and, in most cases, has restricted turndown and reaction to load fluctuations. Depending on the requirements, an SCR system with a conventional burner may reduce NOXX emissions to as low as 2.5 ppm. It can also cut energy consumption and handle most plant load fluctuations while maintaining consistent boiler performance.
Low Boiler Pressure
Any boiler that is running at a massive pressure than the process demands can save energy by lowering the boiler pressure. The water/saturation temperature in the boiler is directly proportional to boiler pressure.
Reducing boiler operating pressure leads to larger LMTD between flue gas and lower output stack temperature, higher heat transfer, boiler saturation temperature, lower heat loss, and ultimately lower fuel consumption.
Update The Fan Controls
Upgrades to variable-frequency drives (VFDs) fan controls can assist enhance boiler efficiency by adjusting and controlling the speed of the fan in proportion to the boiler load. By opening and closing a damper, standard constant-speed fan airflow is matched to the boiler load, ensuring that horsepower remains essentially constant regardless of the load.
The exerted output varies three times the fan speed with VFDs. In comparison to a constant speed fan, if a fan works at 75 percent of maximum speed, the necessary horsepower is only 40 percent of full load. VFDs can enhance the service life of the fan motor, save maintenance costs, and dramatically reduce noise levels, in terms of saving energy.
Take Effective Measures To Reduce Energy Consumption
A boiler efficiency improvement program has two components: the activities expected to put a boiler to peak efficiency and the actions required to maintain that efficiency. The general recommendations above offer various options for energy and performance improvements; nevertheless, it is necessary to a plant operator to go beyond the immediate needs of the equipment and consider how system characteristics impact the plant’s overall systems.
