Steam System Optimization
Whether your facility is a University campus, a Hospital system or a Processing plant, your steam system optimization and maintenance is material to your operations budget and sustainability programs.
Excess Air and Burner Efficiency
Boiler efficiency depends on the right mix of fuel and air. In theory, there is an amount of air that when mixed with a fixed amount of fuel, will result in perfect combustion: all fuel burnt and all oxygen from the air consumed. Excess air is defined as the amount of air in excess of what is needed for perfect combustion. If a large amount of excess air is introduced, it results in oxygen that isn’t consumed during combustion, and this oxygen absorbs usable heat and carries it up the stack. But because there is no perfect system, some amount of excess air is needed to avoid the creation of carbon monoxide and/or soot (unburned hydrocarbons). The American Boiler Manufacturers Association (ABMA) has a Boiler efficiency calculator that may be helpful in working towards an optimum amount of Excess Air for your steam system application. Two methods of maintaining optimum low excess air levels throughout your cycle are (A) frequently monitoring and calibrating excess air levels or (B) installing digital monitoring controls.
Condensate recovery and return to the boiler increases boiler efficiency, since the condensate is hot and reduces the amount of cold makeup water needed to be heated to create steam in the boiler. Utilizing removable insulation to insulate the condensate return system will further reduce the need for cooler make-up water and boiler chemicals.
Boiler Stack Economizers and Waste Heat Recovery
A stack economizer is an air-to-water heat exchanger that is installed on a boiler stack to recover waste heat from flue gases. These systems are used to preheat the feedwater, using captured heat that would typically be lost to the atmosphere. To optimize the efficiency of the heat exchanger, exact fit blanket insulation prevents much of the radiant heat loss.
Heat Recovery from Boiler Blowdown
To avoid excess concentration of salt in the boiler, concentrated water is blown out, boiler water is removed at a high temperature condition. Continuous boiler surface blowdown heat recovery (BDHR) is the most effective method of purging destructive solids from any steam boiler system. Blowdown heat recovery systems can recover about 90% of the blowdown thermal value. The value varies with volume, boiler pressure, and method/frequency of blowdown.
Radiant Heat Loss Prevention through Engineered Industrial Blanket / Jacket Insulation Methods
Without complete and properly designed insulation, a steam system is likely losing heat throughout its length. Piping insulation is not enough. A single uninsulated steam trap can lose between $30 – $300 per year in wasted energy cost. Multiply that by some 500 steam traps in a particular installation and the facility can see wasted energy costs of $15,000 to $150,000 per year! When you add in the many other components (Valves, Strainers, Boilers, Condensate Tanks, Flanges, and fittings) that make up a steam system one can see the benefit in optimizing with process steam blanket insulation. With removable insulation blankets, you can generate and use less steam to accomplish your process needs because you are losing less radiant heat. Correct insulation leads to reduced heat loss, less fuel burnt and reduced greenhouse emissions.