Boiler Operation Principles Chp. 1

What is a Resistance electric boiler?

A Resistance electric boiler typically is low-capacity boiler, but are more common than electrode electric boiler.

What is a back flow preventer in a boiler?

A back flow preventer is a device consisting of two check valves and an overflow device built into the same body, used to prevent water from backing up into a water supply system. A backflow preventer is used on the water supply to a building or an individual closed-loop system. If one of the check valves should fail, the water flows to the (floor) drain.

What is a condensing boiler?

A condensing boiler is designed to recover some of the heat from water vapor normally discharged to the atmosphere in gases of combustion. Water vapor from the gases of combustion is recovered by just cooling the gases of combustion; 95% efficient. Exhaust fan helps expel gases of combustion.

What is an industrial watertube boiler?

AN industrial watertube boiler consists of multiple drums. Steam and water drum(s) located above the mud drum(s) are connected by tubes. Gases of combustion are directed around the tubes by baffles, and the heated water rises to the steam and water drum where steam is released.

How does a boiler's internal surface increase efficiently?

An internal furnace is a furnace in a boiler that is surrounded by heating surface. This allows fuel to burn more efficiently as it mixes with a greater quantity of air.

Opaque object is?

An opaque object is non-translucent (retains light waves, i,.e metal wood, skin, etc) and does not let transmitted radiant energy pass through, thus becoming thermal energy.

Combustion is composed of what 3 ingredients?

Combustion is the rapid union of oxygen with an element or compound that results in the release of heat. Fuel, Oxygen and Spark (or heat) are needed for complete combustion. It takes approximately 14 lb to 15 lb of air to burn one pound of fuel. Nitrogen is NOT combustible.

What is a wetback firetube boiler?

In a Wetback firetube boiler, a water cooled turn-around chamber directs gases of combustion from the furnace to the tube bank. A tube bank is an assembly of tubes in the boiler.

Who developed the first reciprocating steam engine?

James Whatt of Scotland in 1736.

What is thermodynamics?

Thermodynamics is the science of thermal (heat) and how it transforms to and from other forms of energy. Thermodynamics relates to events that occur as heat is generated by the combustion of a fuel and is used to produce steam and hot water in a boiler. 1st and 2nd laws apply to boiler operation.

What are the 4 systems that boilers share in common?

1) Feedwater System supplies water to boiler, 2) Fuel System provides fuel to boiler, 3) Draft system regulates the flow of air to and from the boiler, 4) Steam system collects, controls, and distributes the steam.

What is a Boiler?

A Boiler is a closed metal container (pressure vessel) in which water is heated to produce steam or heated water.

What is a British thermal unit (Btu)?

A Btu is the amount of heat energy required to raise the temperature of one (1) pound of water one (1) degree Fahrenheit (F).

What is a firebox boiler?

A Firebox Boiler is a firetube boiler that has a round top and flat sides. The firebox boiler has an internal furnace that houses the flames from the burner and water legs that extend down the sides of the boiler. Steam produced in the steam space is routed out of the steam outlet at the top of the boiler. Used for low-pressure steam or hot water heating.

What is a Horizontal Return Tubular (HRT) firetube boiler?

A Horizontal Return Tubular fire tube boiler suspended over a furnace. Its drum is supported by slings from steel beams or by lugs mounted on the drum that rest on the brick setting.

What is a Refuse Boiler?

A Refuse Boiler uses municipal solid waste as fuel that would normally go to waste.

What is a field-erected boiler?

A field-erected boiler is boiler that is constructed on-site. These are large capacity boilers used when load requirements exceed the capacity of package boilers.

What is the significance of a boiler's fitting?

A fitting is a component directly attached to the boiler that is required for the operation of the boiler.

What is a gas?

A gas is a substance that has not definite volume or independent shape that tends to expand indefinitely. Gases can be compressed.

What is a high pressure boiler

A high pressure boiler is a boiler with an MAWP of more than 15 psi.

What is a hot water supply boiler?

A hot water supply boiler is a low pressure hot water heating boiler with a volume of more than 120 gallons, or a heat input of more than 200, 000 Btu/Hr, or an operating temperature of more than 200F, that provides hot water to be used externally to itself.

What is a liquid?

A liquid is a substance that flows freely and has a definite volume, but no independent shape.

What is a low pressure boiler?

A low pressure boiler is a boiler with the MAWP of not more than 15 psi. Used in schools, apartments, warehouses, and factories.

What is a low pressure hot water heating boiler?

A low pressure hot water heating boiler is a boiler in which water is heated for the purpose of supplying hot water at pressures of not more than 160 psi and temperatures of not more than 250 F.

What is the max operating pressure for a low pressure steam heating boiler?

A low pressure hot water heating boiler is a boiler in which water is heated for the purpose of supplying hot water at pressures of not more than 160 psi and temperatures of not more than 250 F.

What is a package boiler?

A package boiler is a boiler that is preassembled at the factory. It is a self-contained unit complete with all fittings for hook-up and operation in place.

What is a pass?

A pass is the path or area where gases of combustion travel the length of the boiler.

What is a Power hot water boiler, or High temperature water boiler?

A power hot water boiler is a boiler used for heating water or liquid to a pressure of more than 160 psi or to a temperature of more than 250F.

What is a power steam boiler?

A power steam boiler is a boiler in which steam or other vapor is generated at pressures of more than 15 psi.

What is a small power boiler?

A small power boiler is a boiler with a pressure of more than 15 psi but not more than 100 psi and having heat input less than 440, 000 Btu/hr

What is a solid?

A solid is a substance without an internal cavity that has a definite size and shape. A solid resists deforming forces to remain its original shape.

What is a tube sheet?

A tube sheet is a metal sheet into which boiler tubes are mounted.

What is a Waste boiler?

A waste boiler uses fuel or waste heat from an industrial process that would normally be wasted. These waste boilers can use heat from the incineration of municipal and industrial waste, wood, bark, oil.

Absolute Pressure

Absolute pressure (psia) is the sum of gauge pressure and atmospheric. Psia = psig + P (atmospheric pressure).

What is a boiler's accessory?

An accessory is a piece of equipment not directly attached to the boiler that is required for the operation of the boiler.

What is an electric boiler?

An electric boiler has heat generated by electrical resistance or an electric arc; operation is less complex. They operate at up to 16,000 Volts and are 25 to 50 % half the size of fossil fuel boiler.

What is an Electrode electric water heater?

An electrode electric boiler, heat is generated by an arc produced by an electric current flowing from one electrode to another electrode.

Atmospheric Pressure

Atmospheric pressure is pressure caused by the weight of air surrounding the earth. Standard atmospheric pressure (P) is 14.5 pounds per square inch (psi) at sea level.

What is Atomization of fuel oil?

Atomization is the breaking up of fuel OIL (only) into small particles (fine spray) to maximize contact of fuel with air for combustion efficiency. This atomization does Not apply to gas or coal.

What is a bent-tube watertube boiler?

Bent-tube watertube boiler has shaped tubes surrounded by gases of combustion. For low and high pressure steam or hot water applications.

Causes of natural circulation of water in boiler.

Biggest cause of natural water circulation in boiler is the difference in density between the steam bubbles and the water. The other main cause comes from the density and temperature of the water in the boiler; heated water (lighter) rises and cooler (denser) falls to take its place, repeating cycle.

What is a boiler Horse Power (BHP)?

Boiler Horse Power (BHP) is the power required to evaporate 34.5 lb/Hr of hot water at a temperature of 212F. One BHP is equivalent to 33,472 Btu/Hr

How to convert Fahrenheit to Celsius.

C = (F-32) / 1.8

What is a Cast Iron Boiler, aka porkshop boiler?

Cast iron boiler has gases of combustion flowing around cast iron sections that contain water. There are no tubes in a cast iron boiler. The cast iron sections function similar to watertubes in a watertube boiler. These sections also function as vessels to contain and direct the water around the internal furnace. These individual sections have a pork chop shape. These are limited to low-pressure steam or hot water for heating.

Describe Change of state.

Change of state is the process that occurs when enough heat is added or removed to change a substance from one physical state to another.

What is a commercial watertube boiler?

Commercial watertube boiler produces steam or hot water for commercial or medium-size applications.

Define Conduction.

Conduction is heat transfer that occurs when molecules in a material are heated and the heat is passed from molecule to molecule through the material. There is No flow of material.

Define Convection.

Convection is the heat transfer that occurs when currents circulate between warm and cool regions of a fluid. A fluid takes shape of its container, as gas (steam) or liquid (water)

What is fossil Fuel?

Fossil Fuel is derived from underground plant and animal remains over time.

When did steam power have the greatest impact?

During the Industrial Revolution of the 18th Century and early 19th century.

How to convert Celsius to Fahrenheit.

F = (1.8 x C) + 32

What is feed water composed of?

Feed water is the combination of make-up water and condensate . This water is treated for use in a boiler. The feedwater pump takes water from condensate receiver tank (surge tank) back to the boiler to repeat cycle.

What is a firetube boiler?

Firetube boiler is a boiler in which heat and gases of combustion pass through tubes surrounded by water.

First Law of Thermodynamics is?

First law of thermodynamics is the law of energy conservation. It states, "Energy cannot be created or destroyed but can be changed from one form to another". Exp. the combustion of a fuel in its chemical energy is changed to thermal energy.

Define Heat.

Heat is the form of energy identified by a temperature difference or a change of state.

Define Heat Transfer.

Heat transfer is the movement of heat from one material to another; via Conduction, Convection, and or Radiation.

What is a boiler's heating surface?

Heating surface is the part of the boiler where water is on one side and heat from the gases of combustion on the other. i.e. the bottom of a pot on a burner.

What is a dryback firetube boiler?

In a dryback fire tube boiler there is a refractory lined (brick or non-flammable material) chamber outside of the vessel which directs the gases of combustion from the furnace to the tubes.

What is a Watertube boiler?

In watertube boiler water heat from the flames and gases of combustion is transferred to the water passing through the tubes. Baffles direct the gases of combustion for multiple passes to obtain maximum efficiency; they provide higher demand for steam pressure than firetube boilers.

What is Latent Heat?

Latent Heat is identified by a change in state and no temperature change of the substance. Latent heat is the added energy that changes ice to water and water to steam.

what does MATT stand for?

M= mixture of air/fuel at proper ratio. A= Atomization of fuel oil. T= temperature of air, fuel, and furnace which must be maintained for complete combustion. T= time required to achieve complete combustion.

What is Maximum Allowable Working Pressure (MAWP)?

MAWP is the maximum pressure in pounds per square inch (psi) at which a boiler can be safely operated.

What is make up water in a boiler?

Make up water is fresh water introduced to a boiler to make up for the water loss due to leaks or lost condensate.

What is a membrane boiler?

Membrane boiler is a watertube boiler that uses strips of metal alloy welded between the tubes to form a seal. Gases of combustion pass across the tubes to heat water. These boilers can result in savings up to 50% in floor space and up to 40% in overall weight.

Firetube Boiler, a.k.a Scotch Marine boiler

Originally designed for use on ships are long, horizontal, cylindrical-shaped vessels with an internal furnace and gases of combustion inside the tubes. The internal furnace and tubes are housed within a larger vessel that contains water and steam. The tubes are supported by tube sheets, front and back. Commonly found in industry, this boilers are used for hot water and low-and high pressure steam for heating and process applications.

Types of combustion.

Perfect combustion occurs when all the fuel is burned using only the theoretical amount of air, which neither leaves extra air nor extra fuel. Incomplete type occurs when not all the fuel is burned, flames yields black smoke.

Define Gasses of Combustion?

The gases produced by the combustion process in a boiler and discharged to the atmosphere.

Define Primary air.

Primary air is air supplied to a burner to mix directly with gas or to atomize fuel oil and control the rate of combustion, thus determining the amount of fuel that can be burned.

Define Radiation heat transfer.

Radiation heat transfer occurs as radiant energy (electromagnetic waves) without a material carrier. Radiant energy waves move through space without producing noticeable heat, but heat is sensed upon striking an opaque object (non-translucent).

What is saturated steam?

Saturated Steam is pure steam at a temperature that corresponds to the boiling point of water at a specific pressure.

Define Secondary Air

Secondary Air is the air supplied to the furnace to control combustion efficiency by controlling how completely the fuel is burned. Supplying air above theoretical amount is called EXCESS Air.

What is sensible heat?

Sensible heat is the heat that causes a temperature to change that can be measured with a thermometer or sensed by a person. There is no change of state.

Define Steam now...

Steam is the vapor that forms when water is heated to its boiling point; immediately over 212 F degrees, thus requiring heat over 180 Btu

What kind of steam becomes condensate?

Steam that has lost its heat (below 212 F) and returned to water is called Condensate.

What is a straight-tube waterboiler?

Straight-tube waterboiler has straight tubes surrounded by gases of combustion. Water enters the steam drum through an internal feedwater line; similar to bent-tube watertube boiler.

What is Temperature Difference?

Temp difference is the difference between the temperatures of 2 materials, the temperatures on both sides of a material, or the initial and final temperatures of a material through which heat has been transferred.

What is temperature?

Temperature is the measurement of degree or intensity of heat. Temperature can be measured with a glass thermometer.

Second Law of thermodynamics is?

The second law of thermodynamics is the natural (no energy needed) flow of energy. Heat always flows from a material having higher temperature to a material having a lower temperature. This law applies to all methods of heat transfer.

What is thermal efficiency?

Thermal efficiency is the ratio of heat absorbed by the water to the heat provided by the fuel. 95% is a common boiler's thermal efficiency

What is a watertube boiler?

Watertube boiler is a boiler in which water passes through tubes surrounded by gases of combustion.