Steps to Select the Proper Industrial Watertube Boiler
When a process application requires higher pressures, large quantities of steam or the possibility of additional heat through integrally mounted superheaters, an industrial watertube (IWT) boiler is the best solution. IWT boilers are noted for their fast steaming capability. Steam is generated quickly due to the boiler's relativity low water content. This allows it to respond rapidly to changing load demands. To select the proper IWT boiler for an application, consider these six basic evaluation steps.
There are different types of firetube boiler designs, including dry back and we back ones with either an integral or gun burner. No matter the type, in a firetube boiler both radiant and convective forces work to transfer heat from the burner to the water within the vessel.
The firetube boiler has been around for more than a century, powering the steamboats and steam locomotives that played a major role in the industrialization of America. Today, a broad range of industries count on the firetube boiler to provide comfort heating and process heating where higher temperatures and pressures are required.
To properly execute a burner retrofit, a burner's flame shape and length, or flame envelope, must be matched to the furnace or combustion chamber. This ensures a high heat transfer without impinging on the furnace walls on a manner that could be detrimental to the furnace or convection pass materials.
Analyzing Boiler Room Control Data to Improve Operations
Today's boiler room controls are capable of generating a lot of data. Being able to understand the data and how to apply it will help a facility reduce energy costs and conserve resources as well as improve uptime and safety.
Properly conducted, a boiler room assessment helps increase efficiency, sustainability, reliability and safety. Any facility that consistently focuses on these areas will perform at its optimal level. For most facilities, an outside specialist should conduct the boiler room assessment because it requires a specific methodology and expertise.
Boilers have a number of built-in controls to protect the equipment, operating personnel and facility from disaster. Advancements in boiler design and control systems have improved boiler safety and efficiency over the years, but these advancements are no substitute for an ongoing maintenance program.
Water is a universal solvent that contains dissolved or soluble gasses, which are highly corrosive when exposed to boilers and boiler system components. Water comes in contact with various minerals in the ground, which when dissolved end up in a boiler’s feedwater and need to be removed. Deaeration is one of the best ways to remove oxygen and carbon dioxide in boiler feedwater. Other impurities can be controlled through a good water treatment program, including proper chemicals and dosing of the substances.
The fuel spend in a manufacturing or process operation is a significant part of the company's operating budget. Studies show the plants waste as much as $0.27 to $0.39 of every dollar due to poor energy practices. Identifying and correcting steam energy losses can add thousands of dollars to a company's bottom line.
Boiler tuning is necessary to maintain efficiency as well as to ensure reliability and safety. Tuning the burner during the spring and again in the fall is recommended because of the dramatic air temperature and density changes that occur during these seasons.
According to a study conducted by the National Board of Boiler and Pressure Vessel Inspections, poor maintenance practices or a defective low water cutoff causes most boiler incidents, including those that result in injuries and building damage.
There are many different types of boilers on the market today. Deciding which boiler is best for your application should take into account a number of variables, including design type, operating pressure, capacity, physical size requirement and lifecycle cost.
In the boiler-burner industry, most experts agreed that NO comprises about 95% of total NOx, with NO2 making up the remaining 5%. But, more recent studies have shown that NO2 can make up an appreciable amount of the total NOx formed, particularly at very low NOx levels.
Today’s published boiler efficiency ratings are calculated by manufacturers using a 15% excess air level. The reason efficiency ratings are calculated using 15% excess air (or 3% O2) is that research has proven that 15% is the optimal amount of excess air to introduce into the boiler combustion process.
Steps to Properly Treat Boiler Water Part 2 – Chemical Means
To maximize boiler efficiency and ensure equipment longevity, it is important to properly treat boiler feedwater and keep the internal boiler surfaces clean. Water contains minerals and gases, which when heated lose their solubility and become very hazardous to the boiler and its connected components.
Steps to Properly Treat Boiler Water Part 1 – Mechanical Means
Boiler water treatment is important for proper operation and maintenance of a boiler system. If proper water chemistry is not followed and maintained, a boiler will begin to have problems within the first year, and its useful life will be significantly shortened.
In many boiler systems, the greatest single cause of heat loss is flue gas exiting through the stack. Reducing this loss is important to increase boiler system efficiency and reduce operating costs. The following are some of the heat recovery options available for boilers today.
Most of the time, boiler systems in operation for 20 years or more are only 60- to 70-percent efficient, which wastes unnecessary energy and money every day. After about 20 years of service, a typical burner loses its effectiveness. Linkage joints, cams and other moving parts wear out, and the burner’s ability to keep tight control on the fuel-air ratio becomes degraded.
Why Ultra – High Turndown is Bad for Hydronic Condensing Boilers
Today, hydronic boilers can approach near-perfect efficiency due to the advancements of condensing technology. Several manufacturers promote ultra-high turndown as the solution to efficiently meeting low seasonal, partial-load demands. By understanding condensing boiler operation and the basics of thermodynamics, one will realize that an extremely high-turndown burner on a hydronic condensing boiler does not promote the highest system efficiency, but actually can make the system less efficient.
Steps to Consider When Selecting a Boiler Exhaust System
Proper design and installation of an exhaust system helps to ensure that a boiler system operates at peak efficiency. Boiler inefficiency, burner shutdowns and flame ignition failure upon start-up can result from a poorly designed stack system.
Selecting the right-size pump for a hydronic boiler requires knowledge of the system. The first step is to determine the water flow rate, measured in GPM or gallons per minute. Calculate this by taking the boiler's output, rated in BTUs, and divide it by 500 times the delta T, which is typically 20, but can be 30 or 40 in newer systems.
The Area Source Rule requires that a tune-up be conducted every two or five years depending on the boiler and fuel type. Under the EPA's Area Source Rule, most existing boilers are subject to an initial tune-up which must be completed by March 21, 2014.