OPTIMIZE YOUR BOILER PROJECT
Turbosteam has the knowledge and expertise to maximize your project.
There are many decisions to be made when considering a boiler replacement project. Perhaps no other piece of equipment is more important to a facility than the boiler. Proper boiler selection, to meet the needs of the application, is a critical factor in the design of any steam or hot water system.
If the boiler application has instantaneous load demands, whereby a large volume of steam is required for a short period of time, a boiler with a large energy storage reserve, such as a fire tube, should be considered. If the application dictates large variances in load demand, where the load swings frequently for long periods of time, the best choice is probably a water tube type boiler, because it contains less water and can respond to the variances in steam flow rate demand more rapidly.
Typical fire-tube boilers designs allow operating pressures of up to 350 psig (2400 kPa), while water boilers allow boiler pressures up to 900 psig (6200 kPa).
When selecting a boiler, increasing pressure above that required in the process can provide great long term economic value with the addition of backpressure steam turbine generator. The incremental cost of the boiler is not very high, but the power generated with the steam turbine can provide significant savings. Below is an economic case study for a boiler replacement project. The first column represents replacing a boiler in kind with the same pressure as that required by the process - 100 psig. The second column presents a boiler designed for 600 psig, sending steam through a backpressure turbine to provide the required process pressure of 100 psig. As shown the boiler replacement based only on efficiency improvements for the new boiler provide a simple payback of 10.4 years, where increasing the boiler design pressure and adding a backpressure turbine reduces the simple payback to 3.6 years.
| Old Boiler Efficiency | 75% | Fuel Cost | $5.00 /MMBtu |
| New Boiler Efficiency | 82% | Electric Cost | $0.09 /kWhr |
| Boiler Replacement | Boiler Replacement with Turbine |
|
|---|---|---|
| Steam Flow | 25,000 lb/hr | 25,000 lb/hr |
| Steam Pressure | 100 psig | 600 psig |
| Boiler Fuel Savings | $111,198 | $95,979 |
| Additional Fuel Cost | ($37,888) | |
| Electric Savings | $276,433 | |
| Total Annual Savings | $111,198 | $410,299 |
| Simple Payback | 7.6 | 3.6 |
To estimate your potential savings visit Turbosteam's Calculator.
A Note About Boiler Horsepower
The term boiler horsepower dates back to the Philadelphia Centennial Exhibition of 1876, where the best steam engines of that period were tested. The average steam consumption of those engines was determined to be equivalent to saturated steam generated at 70 psig (480 kPa). This definition eventually evolved to present industrial practice where boiler horsepower is defined as a boiler thermal output equal to 33,475 BTU/h.
The amount of power that can be obtained by a steam engine or steam turbine based on boiler horsepower varies so widely that use of the term is entirely obsolete for these purposes. The term makes no distinction as to the steam pressure or temperature which is produced or whether the steam is condensed. It merely defines a thermal output of a boiler. However, it provides a convenient short cut for comparing boiler sizes.