Close to 40% of all fossil fuel burned by industry is consumed in steam production. Simple steps can have a large operational impact on the cost of fuel, water, treatment, and labor. The chart shows a typical breakdown of these costs where fuel consumption is the primary expense.
Here are five strategies for improving your boiler operating efficiencies.
1. Maintaining a Clean Heat Exchanger
Clean boiler heat exchange surfaces allow for maximum heat transfer from the burning fuel to the boiler water. Feedwater quality is critical to prevent deposit formation within the boiler and maintain peak efficiency. Water-side deposits will insulate heat exchange surfaces and sharply increase fuel consumption. Industry standards suggest that 1/16” of deposit can increase fuel costs by 12.5%. Since fuel consumption is typically the major cost in boiler operation, this can have a major impact on overall efficiencies.
Regular monitoring of water chemistry and critical operating parameters (i.e. stack, tube, or coil temperatures) is recommended to provide early indication of fouling. Visual inspections of the water-side of a boiler should also be performed to ensure the effectiveness of the current treatment program.
2. Automating Boiler Blowdown
The production of steam in a boiler leaves behind dissolved and suspended solids in the water. These solids accumulate with continued steam production necessitating regular blowdown of boiler water. The boiler water that is removed during blowdown has been chemically treated and heated to operating temperature. As a result, excessive boiler blowdown increases the treatment, fuel and water costs. Too little boiler blowdown can cause carry over of boiler water in steam also resulting in excess fuel and chemical consumption. The installation of an automated blowdown control system allows for active monitoring of the boiler conductivity and optimizes the volume of blowdown based on fluctuating steam loads. A well designed automated blowdown system will lead to increased boiler efficiencies and promote improved steam quality.
3. Reduction in Blowdown Requirements
Boiler blowdown rates are mainly dependent on the amount and type of minerals entering the system. The installation of pretreatment equipment that will alter or remove the minerals in the make-up water can significantly reduce the required blowdown and the consumption of water treatment chemicals. Examples of this equipment include softeners, dealkalizers, de-ionizers and reverse osmosis units (ROs).
To ensure you achieve the maximum amount of savings, it is important to thoroughly evaluate all of the pretreatment options for your specific application and water source.
4. Maximize Condensate Return Rate and Temperature
Returning high temperature condensate will reduce the cold water make up rates and save on water, energy, and treatment costs. Since condensate typically contains low levels of dissolved solids, it will also reduce the required blowdown rates providing further savings. Your system design and use of steam will dictate the amount of condensate that can be returned. With potential savings typically over $30 per thousand gallons of condensate, the economic justification is often available to install the equipment necessary to return more condensate or repair any failures in the existing network that are leading to condensate losses.
Maximizing the energy in the condensate that is already being returned is another consideration. Returning pressurized condensate will reduce the flash losses and increase the overall energy savings. Insulation of the return piping will also minimize heat losses to the environment.
5. Metering and Benchmarking Utility
Though the installation of meters on a steam system may not directly impact the efficiency of a boiler, the data they collect will allow you to gain insight into the current operating conditions and provide a clearer understanding of the overall cost of steam production.
With the availability of the usage data from metering, opportunities for improved steam plant efficiency can be identified and quantified. For example, control of boiler pressure, firing order and production scheduling based on steam plant load can have a major impact on the cost of steam generation. By benchmarking and tracking steam costs, optimal operating profiles can be identified and any excursions quickly corrected.
Your plant’s steam system offers a multitude of opportunities to identify energy reduction projects. This includes having a water treatment vendor that can design and maintain pretreatment equipment, a chemical program, and automation controls to optimize water conditions within the boiler. Klenzoid engineers and chemists are recognized thought leaders in the development of industry best practices. Our data-driven processes will get your steam systems operating at the lowest possible life-cycle cost and proactively maintain them there.