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Boilers By Ryan Majkut. Objective: to discuss different types of boilers and explain how they work. What is a Boiler?. A water containing vessel which transfers heat from a fuel source (oil, gas, coal) into steam
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BoilersBy Ryan Majkut Objective: to discuss different types of boilers and explain how they work
What is a Boiler? • A water containing vessel which transfers heat from a fuel source (oil, gas, coal) into steam • This steam is piped to a point where it can be used to run production equipment, to sterilize, provide heat, to steam-clean, etc • Boilers are commonly used to heat larger office buildings • They work by sending hot water through pipes around the building that heat up the air around them and cause the room to get warmer
Fire-tube Boiler • A fire-tube boiler was more common in the 1800s. It consists of a tank of water perforated with pipes. The hot gases from a coal or wood fire run through the pipes to heat the water in the tank, as shown here: • The whole tank is under pressure, so if the tank bursts it creates a major explosion
Water-tube Boiler • More common today are water-tube boilers, in which water runs through a rack of tubes that are positioned in the hot gases from the fire
Boiler Systems • Closed System- The energy given up by the steam is sufficient to convert it back into the form of water. When 100% of the steam produced is returned to be reused, the system is called a closed system. • Open System- Since some processes can contaminate the steam, it is not always desirable to feed the condensate back into the boiler. A system that does not return the condensate is called an open system. A More Complex Water-tube Boiler
Condensing Boiler • uses a secondary heat exchanger or condensing coil to recover heat from the hot flue gases • The temperature of this flue gas will be near to that of flame.
Feed Water Contamination • The boiler receives the feed water, which consists of recovered condensed water (return water) and fresh water (make-up water) • The steam, which escapes from the boiler, frequently contains liquid droplets and gases • The water remaining in liquid form at the bottom of the boiler picks up all the foreign matter from the water that was converted to steam • These impurities lead to poor heat transfer and reduction in the efficiency of the boiler • The impurities must be blown down by the discharge of some of the water from the boiler to the drains
More Complex Systems • Boilers may contain additional components such as: • Economizers to increase the boiler efficiency • Superheaters to heat the steam above the saturation temperature • Process heaters and steam turbine systems to power a variety of steam • Feedwater heaters to remove dissolved gases, such as oxygen
References • http://www.alken-murray.com/Boilerworks.html • home.btconnect.com/.../ condensing_boiler.htm • http://www.business-wiz.com/products/boilers.html • http://www.abma.com/pack_ft_boilers.php • www.lenntech.com/boiler/ boiler-feed-water.htm