Size of the combustion chamber of a furnace depends upon the (A) Heat release rate of the fuel (B) Preheat temperature of fuel & air (C) Method of mixing the fuel & air (D) All (A), (B) and (C)

Size of the combustion chamber of a furnace depends upon the
(A) Heat release rate of the fuel
(B) Preheat temperature of fuel & air
(C) Method of mixing the fuel & air
(D) All (A), (B) and (C)
by

1 Answer

Answer :

(D) All (A), (B) and (C)
by

Related questions

The amount of combustible escaping unconsumed from the furnace, depends upon the (A) Air supplied and furnace temperature (B) Burner design (thoroughness of mixing versus stratification) (C) Air preheat and the flow of gases in the furnace (mixing by induction, by acceleration or by change of direction) (D) All (A), (B) and (C)

Description : The amount of combustible escaping unconsumed from the furnace, depends upon the (A) Air supplied and furnace temperature (B) Burner design (thoroughness of mixing versus stratification) (C) Air preheat and the flow of ... , by acceleration or by change of direction) (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Coke oven gas is a better fuel than blast furnace gas, because of its higher (A) Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity) (B) Adiabatic flame temperature (C) Heat release rate (thus requiring smaller combustion chamber) (D) All (A), (B) and (C)

Description : Coke oven gas is a better fuel than blast furnace gas, because of its higher (A) Calorific value, cleanliness and relatively low distribution cost (due to its low specific gravity) (B) Adiabatic flame temperature ... release rate (thus requiring smaller combustion chamber) (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

A fuel with high heat release rate will (A) Require smaller combustion chamber (B) Have high calorific value (C) Have high adiabatic flame temperature (D) None of these

Description : A fuel with high heat release rate will (A) Require smaller combustion chamber (B) Have high calorific value (C) Have high adiabatic flame temperature (D) None of these

Last Answer : (A) Require smaller combustion chamber

Turndown ratio of a burner gives an idea of the __________ in the furnace. (A) Range of fuel firing rates (B) Volume of the combustion chamber (C) Maximum heat input rate only (D) Minimum heat input rate only

Description : Turndown ratio of a burner gives an idea of the __________ in the furnace. (A) Range of fuel firing rates (B) Volume of the combustion chamber (C) Maximum heat input rate only (D) Minimum heat input rate only

Last Answer : (A) Range of fuel firing rates

In practical operation of any furnace, zero oxygen percentage or theoretical CO2 percentage in flue gas is rarely achieved, because of (A) Use of non-preheated combustion air (B) Use of pulverised solid fuels (C) Imperfect mixing of fuel & air and infiltration of air (D) Use of excessive positive draft in the furnace

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Last Answer : (C) Imperfect mixing of fuel & air and infiltration of air

Smoke is produced due to (A) Insufficient supply of combustion air and insufficient time for combustion (B) Poor quality of fuel and improper mixing of fuel & combustion air (C) Poor design & overloading of furnace (D) All (A), (B) and (C)

Description : Smoke is produced due to (A) Insufficient supply of combustion air and insufficient time for combustion (B) Poor quality of fuel and improper mixing of fuel & combustion air (C) Poor design & overloading of furnace (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

The function of an economiser in a boiler is to preheat the (A) Feedwater (B) Combustion air (C) Pulverised coal (D) Furnace oil

Description : The function of an economiser in a boiler is to preheat the (A) Feedwater (B) Combustion air (C) Pulverised coal (D) Furnace oil

Last Answer : (A) Feedwater

Which of the following is not increased by using preheated combustion air in place of ordinary air at room temperature? (A) Calorific value of the fuel (B) Flame temperature achieved (C) Speed of combustion of fuel (D) Heat transfer rate to the stock in the furnace

Description : Which of the following is not increased by using preheated combustion air in place of ordinary air at room temperature? (A) Calorific value of the fuel (B) Flame temperature achieved (C) Speed of combustion of fuel (D) Heat transfer rate to the stock in the furnace

Last Answer : (A) Calorific value of the fuel

Amount of coal lost in ash particle, which is carried through the boiler system, depends upon the (A) Physical nature, ash content and fineness of the coal (B) Amount of excess air supplied and load on the boiler (C) Type of burner and combustion chamber (D) All (A), (B) and (C)

Description : Amount of coal lost in ash particle, which is carried through the boiler system, depends upon the (A) Physical nature, ash content and fineness of the coal (B) Amount of excess air supplied and load on the boiler (C) Type of burner and combustion chamber (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Combustion of pulverised fuel (A) Requires larger combustion chamber than rich gaseous fuel (B) In a metallurgical furnace does not contaminate the product in the furnace by ash from fuel (C) Suppresses the discharge of fine dust and grit into atmosphere (D) All (A), (B) and (C)

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Last Answer : (A) Requires larger combustion chamber than rich gaseous fuel

Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the (A) Requirement of large volume combustion chamber (B) Risk of explosion (C) Chances of clinker formation (D) Incomplete combustion of coal

Description : Temperature of preheated air used for the transportation of pulverised coal through pipes to the burner of a boiler furnace is restricted to a maximum limit of about 300° C to avoid the (A) ... chamber (B) Risk of explosion (C) Chances of clinker formation (D) Incomplete combustion of coal

Last Answer : (B) Risk of explosion

The optimum percentage of excess air for combustion depends upon the__________ of the fuel.(A) Type (solid, liquid or gaseous)(B) Calorific value(C) Sulphur content(D) Ignition temperature

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Last Answer : (A) Type (solid, liquid or gaseous)

Major sources of noise in furnace operation arises from air inspirators, combustion, side wall vibrations and fluctuation in the process heat load. A 50% increase in fuel firing rate may increase the furnace noise level by about __________ decibels. (A) 3 (B) 30(C) 7 (D) 70

Description : Major sources of noise in furnace operation arises from air inspirators, combustion, side wall vibrations and fluctuation in the process heat load. A 50% increase in fuel firing rate may increase the furnace noise level by about __________ decibels. (A) 3 (B) 30 (C) 7 (D) 70

Last Answer : (A) 3

Fuel economy in furnaces can be achieved by (A) Using oxygen enriched combustion air (B) Preheating the combustion air (C) Reducing the heat loss through furnace openings & doors (D) All (A), (B) and (C

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Last Answer : (D) All (A), (B) and (C

The main drawback of supplying more excess air in the combustion of fuel is the (A) Excessive power requirement of air blower (B) Enhanced sensible heat loss in the flue gas (C) Intermittent and uncontrolled combustion of the fuel (D) High exit flue gas temperature from the furnace

Description : The main drawback of supplying more excess air in the combustion of fuel is the (A) Excessive power requirement of air blower (B) Enhanced sensible heat loss in the flue gas (C) Intermittent and uncontrolled combustion of the fuel (D) High exit flue gas temperature from the furnace

Last Answer : (B) Enhanced sensible heat loss in the flue gas

Rate of heat release in a furnace, which is the measure of heat intensity, is defined as (A) kcal/hr/m3 combustion space (B) kcal/m3 combustion space (C) kcal/hr (D) None of these

Description : Rate of heat release in a furnace, which is the measure of heat intensity, is defined as (A) kcal/hr/m3 combustion space (B) kcal/m3 combustion space (C) kcal/hr (D) None of these

Last Answer : (A) kcal/hr/m3 combustion space

In reverberatory furnace, charge is heated mainly by (A) Conduction (B) Natural convection (C) Radiation of heat from the roof of the combustion chamber (D) None of these

Description : In reverberatory furnace, charge is heated mainly by (A) Conduction (B) Natural convection (C) Radiation of heat from the roof of the combustion chamber (D) None of these

Last Answer : (C) Radiation of heat from the roof of the combustion chamber

Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by (A) Preheating the combustion air (B) Oxygen enrichment of combustion air (C) Preheating the fuel gas (D) All (A), (B) & (C)

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Last Answer : (D) All (A), (B) & (C)

Design of waste heat boiler for recovery of waste heat from furnace gases depends upon the(A) Quantity & temperature of waste gas(B) Dust concentration & nature of dust in waste gas(C) Corrosive nature of the waste gas(D) All (A), (B) and (C)

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Last Answer : (B) Dust concentration & nature of dust in waste gas

Supply of excess air for complete combustion of fuel is necessitated to facilitate (A) Its thorough mixing with air (B) Attainment of chemical equilibrium (C) Attainment of high temperature (D) None of these

Description : Supply of excess air for complete combustion of fuel is necessitated to facilitate (A) Its thorough mixing with air (B) Attainment of chemical equilibrium (C) Attainment of high temperature (D) None of these

Last Answer : (A) Its thorough mixing with air

Advantages of fluidised bed combustion are (A) Reduced NOx formation in flue gas (B) Lower furnace operating temperature (C) High heat transfer rate (D) All (A), (B) & (C)

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Last Answer : (D) All (A), (B) & (C)

Oxygen enrichment of combustion air does not result in increase of the (A) Flame temperature (B) Oxygen in the flue gas (C) Stack loss (D) Heat transfer rate in the furnace

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Last Answer : (B) Oxygen in the flue gas

Combustion of pulverised coal as compared to that of lump coal (A) Develops a non-luminous flame (B) Develops a low temperature flame (C) Can be done with less excess air (D) Provides a lower rate of heat release

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Last Answer : (C) Can be done with less excess ai

Higher furnace temperature cannot be achieved by use of a lean fuel gas in the furnace by (A) Increasing the draft in the furnace (B) Preheating the fuel gas (C) Oxygen enrichment of combustion air (D) Preheating the combustion air

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Combustion of fuel in a furnace with oxygen enriched air results in higher (A) Flue gas volume (B) Flame temperature (C) Fuel consumption (D) Stack loss

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Last Answer : (B) Flame temperature

Which of the following advantages is not associated with the use of preheated air for combustion of a fuel in the furnace? (A) Increase in calorific value of the fuel (B) Increase in flame temperature (C) Reduction in scale losses (D) Saving in fuel consumption

Description : Which of the following advantages is not associated with the use of preheated air for combustion of a fuel in the furnace? (A) Increase in calorific value of the fuel (B) Increase in flame temperature (C) Reduction in scale losses (D) Saving in fuel consumption

Last Answer : (A) Increase in calorific value of the fuel

Use of preheated air for combustion of fuel in the furnace, increases the (A) Scale losses of the furnace stock (B) Calorific value of the fuel (C) Flame temperature (D) None of these

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The main function of primary air in pulverised coal fired burner is to (A) Burn CO to CO2 (B) Dry and transport the coal (C) Have proper combustion by supplying it around the burner (D) Preheat the tertiary air used for complete combustion of CO to CO2

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The rate of scaling of furnace stock depends upon the (A) Temperature (B) Time(C) Nature of atmosphere(D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

In a 4 S diesel engine, the term ‘squish’ refers to the (a) Injection of fuel in the precombustion chamber (b) Discharge of gases from the precombustion chamber (c) Entry of air into the combustion chamber (d) Stripping of fuel from the core

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Last Answer : Ans :c

The advantage of firing pulverised coal in the furnace lies in the fact, that it (A) Permits the use of high ash content coal (B) Permits the use of low fusion point ash coal(C) Accelerates the burning rate and economises on fuel combustion(D) All (A), (B) and (C)

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Last Answer : (C) Accelerates the burning rate and economises on fuel combustion

Combustion is the ideal air/fuel ratio where a. the mixing proportion is correct, b. the fuel is completely burned c. the oxygen is entirely consumed d. All of the above

Description : Combustion is the ideal air/fuel ratio where a. the mixing proportion is correct, b. the fuel is completely burned c. the oxygen is entirely consumed d. All of the above

Last Answer : d. All of the above

The main advantage of forced draft over natural draft is that (A) Combustion of fuel is complete (B) Smaller height chimney can be used (C) Furnace control is easier (D) All (A), (B) & (C)

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Last Answer : (D) All (A), (B) & (C)

Fuel economy in an industrial furnace operation cannot be achieved by the use of (A) Stoichiometric combustion air (B) Non-preheated combustion air (C) Combustion air not enriched with oxygen (D) Recuperators

Description : Fuel economy in an industrial furnace operation cannot be achieved by the use of (A) Stoichiometric combustion air (B) Non-preheated combustion air (C) Combustion air not enriched with oxygen (D) Recuperators

Last Answer : (A) Stoichiometric combustion air

Which of the following fuel gases will require maximum amount of air for combustion of 1 Nm3 gas? (A) Blast furnace gas (B) Natural gas (C) Producer gas (D) Water gas

Description : Which of the following fuel gases will require maximum amount of air for combustion of 1 Nm3 gas? (A) Blast furnace gas (B) Natural gas (C) Producer gas (D) Water gas

Last Answer : (B) Natural gas

Black smoke coming out of the chimney of a furnace is an indication of the use of __________ in the furnace. (A) Low amount of excess combustion air (B) Large quantity of excess combustion air(C) Hydrocarbon fuel(D) Pulverised coal as fuel

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Last Answer : (A) Low amount of excess combustion air

Heat transfer rate to the stock/charge in the furnace does not depend upon the(A) Emissivity of the refractory walls(B) Size of the furnace(C) Use of waste heat recovery equipments(D) Thickness of the stock

Description : Heat transfer rate to the stock/charge in the furnace does not depend upon the (A) Emissivity of the refractory walls (B) Size of the furnace (C) Use of waste heat recovery equipments (D) Thickness of the stock

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Combustion of pulverised coal compared to the lumpy coal (A) Provides better control of furnace temperature (B) Facilitates combustion with lower excess air (C) Provides higher thermal efficiency & flame temperature (D) All (A), (B) & (C)

Description : Combustion of pulverised coal compared to the lumpy coal (A) Provides better control of furnace temperature (B) Facilitates combustion with lower excess air (C) Provides higher thermal efficiency & flame temperature (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the (A) Rate of firing and emissivity of flame (B) Thermal conductivity of the charge & structural materials of furnace (C) Nature of process; whether batch, continuous or intermittent (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

What is defined as the ratio of the net electrical power output to the rate of fuel energy input?  A. Combustion efficiency  B. Thermal efficiency  C. Overall efficiency  D. Furnace efficiency

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Heat transfer rate to the charge/stock in a furnace does not depend upon the (A) Type of fuels viz. solid, liquid or gaseous (B) Flue gas temperature (C) Emissivity of refractory walls (D) Initial temperature of the charged stock

Description : Heat transfer rate to the charge/stock in a furnace does not depend upon the (A) Type of fuels viz. solid, liquid or gaseous (B) Flue gas temperature (C) Emissivity of refractory walls (D) Initial temperature of the charged stock

Last Answer : (A) Type of fuels viz. solid, liquid or gaseous

Deficiency of combustion air during combustion of a gaseous fuel (A) Lengthens the flame (B) Causes heat loss of fuel by its partial combustion (C) Both (A) & (B) (D) Shortens the flame

Description : Deficiency of combustion air during combustion of a gaseous fuel (A) Lengthens the flame (B) Causes heat loss of fuel by its partial combustion (C) Both (A) & (B) (D) Shortens the flame

Last Answer : (C) Both (A) & (B)

The heating capacity of continuous reheating furnace depends upon the (A) Hearth area and furnace temperature (B) Emissivity of the stock (C) Ratio of wall surface to stock surface (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

Too much of excess air in combustion results in high (A) Fuel consumption for the same heat load (B) Stack gas temperature (C) Percentage of oxygen in flue gases (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

Crystal size in a continuous crystalliser depends upon the (A) Rate of heat transfer (B) Degree of turbulence (C) Degree of super-saturation (D) All (A), (B) and (C)

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Last Answer : (D) All (A), (B) and (C)

Stack heat losses can be minimised by (A) Controlling the excess air (B) Oxygen enrichment of combustion air (C) Using low c.v. fuels (D) Maintaining proper draft in the furnace

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Last Answer : (A) Controlling the excess air

Incomplete combustion of fuel in the furnace is judged by high __________ of the flue gases. (A) CO content (B) Dew point (C) CO2 content (D) O2 content

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Last Answer : (A) CO content

Which of the following will generate maximum volume of product of complete combustion (Nm3 /Nm3 of fuel)? (A) Carburetted water gas (B) Blast furnace gas(C) Natural gas(D) Producers' gas

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Last Answer : (C) Natural gas

Higher efficiency in the combustion of solid fuel cannot be achieved by (A) Proper fuel preparation (B) Keeping the flue gas exhaust temperature very high (C) Adopting efficient-fuel firing technique & equipment (D) Supplying correct quantity of combustion air

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