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The correct option is (b) To BURN pulverized coal in presence of Primary and SECONDARY AIR

For explanation: Function of the coal burner is to burn pulverized coal in the presence of primary and secondary air in a boiler FURNACE. Coal burners are classified according to their design and arrangement in the furnace.

The correct choice is (b) Sprockets

To explain: The chain travels over two sprockets. In both chain type and in BAR type stokes. ONE sprocket is placed at the FRONT end and other sprocket is placed at the rear end of the furnace. The front sprocket is connected to a variable speed driving MECHANISM.

Correct option is (c) 60 – 120 rpm

The explanation is: The screw ALONG with the shaft in screw conveyor rotates at about 60 rpm to 120 rpm and carries coal from one end to another. Screw CONVEYORS are DESIGNED to suit different load capacities. These can only be used in very SHORT ranges and tend to get hot if used for longer amount of time.

Right CHOICE is (a) Road transportation

The best I can explain: Road transportation is ideal for transporting coal directly to the point of consumption. Such a MEANS is suitable for supplying coal to a small capacity plant. Trucks or tippers are used to supply coal for this PURPOSE.

The correct answer is (a) By positive displacement pumps

For explanation I would say: In mechanical atomization of ATOMIZING BURNER of oil burners, the oil is pressurized by using a positive displacement pump. It is used in high capacity steam GENERATING furnaces. In order to improve efficiency and flow conditions the viscosity of the oil is reduced by HEATING it to about 120^oC.

Right option is (a) Hot startup with normal LOAD

Best explanation: MILL fires are more often CAUSED due to PYRITE building, hot startup on heavy load, accumulation of coal dust etc. the cause of fire is also dependent upon coal properties that EXCEED pulverizing rating.

The correct option is (a) Because of rolling action between the balls and races

Explanation: The pulverization or crushing action in ball and race mill TAKES between the two moving surfaces called balls and races. The rolling action happens between these two. Then the COAL passes between the rotating elements TIME and again until it has been pulverized to the desired DEGREE of fineness.

Right answer is (b) Centrifugal force

For explanation I would SAY: The COAL pulverized is carried to the burner through the fan. The impurities in the coal CONTAINING heavy particles are thrown over side by centrifugal force as these ENTER the rotating bowl/ the heavy particles thrown out fall into the space below the bowl.

Correct answer is (c) SECONDARY air

The explanation is: The amount of secondary air required to complete the COMBUSTION is blown SEPARATELY and resulting turbulence in the high pressure combustion chamber helps in through MIXING of fuel and air. For better combustion result this TYPE of mixing is done.

Right OPTION is (c) No moving part in furnace

The explanation is: There are no moving parts in the furnace, subjected to high temperature therefore the LIFE of the system is more and the operation is trouble free. The boilers can be started from cold very rapidly and effectively. The external HEATING surface is free from CORROSION and fouling as smokeless COMBUSTION is possible.

The correct option is (b) Bituminous COAL

The best explanation: The under feed method uses bituminous coals which have high VOLATILE matter. The volatile matter gets heated to a high temperature as it passes through incandescent REGION of coal. The volatile matter being at a high temperature before ENTERING the furnace burns quickly when MIXED with secondary air.

Right OPTION is (a) Spreader stoker

The EXPLANATION is: Spreader stoker SYSTEMS are receiving the greatest interest and sales in the market. Depending upon the method of introducing the coal into furnace, stokers are mainly classified into spreader stokers, underfeed stokers, vibrating GRATE stokers and travelling grate stokers.

Right choice is (c) Near water resources

Easiest explanation: An ideal SITE for power plant is near water source. If the plant is SITUATED near the SEA or river, coal can be economically transported in bulk quantity by ships or BOATS or barges. After unloading the coal by mechanical means, coal is EITHER stored in the plants site or conveyed to the plant.

Right choice is (d) Gravity hopper

The BEST EXPLANATION: The coal is fed by gravity from a hopper LOCATED in front of the stoker. The depth of FUEL on the grate is regulated by HAND adjusted gate. The speed of the grate varies at the rate at which the coal is fed to the furnace.

Correct answer is (d) When there is change in induced draught

For explanation I WOULD say: When there are variation made in induced draught by air dampers OPENING due to coupling of motor that’s when RELAY 1 and 2 comes into operation. Relay 1 operates and adjusts the forced draught fan vanes till stability is restored in the combustion chamber. This result in an increased flow rate of air through the passage P. Due to increased flow rate, relay 2 is actuated which speeds up the STOKER motor to supply extra fuel.

The correct CHOICE is (b) Steam GENERATOR

For explanation I would say: A combustion EQUIPMENT is a component of steam generator. It receives the fuel and air proportionals to each other and to the boiler steam demand, mix, ignites and performs other function such as distillation of volatile matter of coal.

The correct ANSWER is (b) Breaking of MOLECULAR structure

Easy explanation: The reactions which TAKE place in the incandescent zone of under-feed stoker is exactly same as in the incandescent zone of over feed stoker except some breaking of molecular structure of volatile matter. Part of the broken volatile matter reacts with the oxygen of air.

Correct option is (b) When there is variation in steam flow rate

Best EXPLANATION: Automatic control combustion SYSTEM comes into action when there is variation in steam flow rate also when there is FLUCTUATION in steam pressure and furnace draft. It is SAFER COMPARED to manual control system and saves manual labour and time.

Right answer is (b) Pulverized coal

For explanation I would say: Pulverized coal is prepared by POWDERING low grade coal with high ash CONTENT. DRY coal is pulverized in pulverizing mills. It burns most EFFICIENTLY when mixed with air and hence it is used in most of the power plants.

Correct answer is (a) HCV = LCV + HV (nH2O, out / nfuel, in)

Explanation: HV – heat VAPORIZATION of water.

nH2O, out– moles of water VAPORIZED.

nfuel, in– NUMBER of moles of fuel COMBUSTED.

High calorific value is equal to low calorific value PLUS, product of heat of vaporization of water and moles of water vaporized by moles of fuel combusted.

Correct option is (c) Coal gas

The BEST I can explain: Coal gas is called as TOWN gas. It is a by-product obtained during destructive distillation of coal. It mainly contains H2, CO, CO2, CH4 and N2.It has a calorific value ranging from 21000KJ/m^3 to 25000KJ/m^3. The gas obtained when coal is heated strongly in the ABSENCE of air is called coal gas.

The correct option is (b) Reducing swift turns and sharp bends

Easiest explanation: The air and ash mixture moving through the pipe at HIGH pressure tends to HIT the WALLS at inner side of pipe when there are number of swift turns and sharp bends made. AVOIDING them can REDUCE the noise up to 50%.

The correct option is (a) BLAST furnace gas

The best explanation: Blast furnace has a very LOW HEATING value. It is obtained as a by-product during blast furnace operation. Due to HIGH percentage of DUST content it should be purified before use. It has a calorific value ranging between 3800 KJ/m^3 to 4200 kJ/m^3. It is used as a fuel in gas engines in steam generation and in steel plants.

Right choice is (b) JUNKER calorimeter

Best explanation: The calorific values of gaseous fuel are defined as the amount of heat liberated by complete combustion of UNIT volume of fuel. SI unit is KJ/m^3. This calorimeter works on PRINCIPLE of burning of a known volume of gas an imparting the heat with maximum efficiency to steadily flowing water and FINDING out the rise in temperature of a MEASURED volume of water.

Right answer is (b) Bomb CALORIMETER

Best explanation: The calorific VALUE of solid of solid and liquid FUEL is defined as the amount of heat liberated by complete combustion of UNIT mass of fuel. In SI unit s it is expressed in kJ/kg. A bomb calorimeter is a type of constant VOLUME calorimeter used in measuring heat of combustion of particular reaction. Bomb calorimeters have to withstand the large pressure within the calorimeter as the reaction is being measured.

The correct option is (b) FLUE gas

Easiest explanation: The PRODUCTS of combustion are in form of flue gas. Flue gas is the gas which is exiting to the ATMOSPHERE via a flue, which is channel for releasing exhaust gas from steam power plant. The flue gas is high in the contamination of NITROGEN, oxygen and carbon dioxide. And also it contains a small amount of pollutants, such as soot and other TYPES of oxides.

Correct option is (d) Rankine

Easiest EXPLANATION: Rankine cycle is a thermodynamic cycle of constant pressure engine that is to convert heat energy into MECHANICAL work and from that following PARTS like adjoined BLADES and shafts are made to run to produce electricity. Otto cycle is used in automobile engine and Brayton cycle is used in heat ENGINES & air jet engine.

Right choice is (c) Utilization of NATURAL RESOURCES

The explanation is: Since most of the power produced is from the natural resources, the estimation of amount of power generated in a country is made by the utilization of its natural resources. The ‘Annual consumption of power ‘WOULD give you the details of power UTILIZED for necessities, it is the amount of power utilized out of wholesome amount of total power produced in the country.

The correct OPTION is (C) Fuel fabricator

Easy explanation: Fuel fabrication PLANTS help in converting enriched uranium into fuel for nuclear reactors. For light water reactors, uranium is received from an ENRICHMENT plant in SOLID form. It is then converted into uranium dioxide powder. This powder is passed into pellets and packed into fuel assemblies.

Right ANSWER is (b) When there is scarcity of water

To explain: Cooling tower is PREFERRED when there is scarcity of water. INSTEAD of circulating the water directly, it is sprinkled in the cooling tower to condense the exhausted steam coming from the turbine. The loss of water DUE to evaporation is compensated by supplying water directly from the river.

Correct option is (b) False

To explain: There is no requirement for any auxiliary steam producing unit since the steam required is drawn from the BOILER present in the system. The steam drawn from the boiler is pressurized and then utilized. Non-requirement of auxiliary unit is ADVANTAGEOUS as it would cut slack in the expenses of SETTING up the plant.

Correct choice is (a) NUCLEAR power plant

For explanation I would say: Since power is generated by nuclear power plant and the nuclear plant needs power to perform its operations. For this purpose steam power plant is used as BASE power plant to generate this power. The power produced base plant acts as a fuel to run the nuclear power plant. And all the cost estimation to PRODUCE the electricity is made by considering base LOAD expenses too.

Right option is (a) Energy value

To EXPLAIN: Energy value (heating value or calorific value) of a substance, usually a fuel or FOOD is the amount of heat RELEASED during the COMBUSTION of a specified amount of it. The energy value is characteristic for each substance. It is measured in units of energy PER unit of the substance, usually mass, such as Kj/Kg, KJ/mol, and kcal/kg.

The correct option is (d) DISTILLATE

Explanation: Distillate is slightly heavier than kerosene and is used as fuel and domestic fuel. It is liquid fuel usually distilled from crude petroleum and produced in fractions. Distillate fuel is a type of fuel for internal COMBUSTION vehicles with either mechanical transmissions or electric transmissions. They are used in automobiles LOCOMOTIVES and AGRICULTURAL machinery as well as space heaters and POWER generators.

The correct option is (d) Hydraulic ash HANDLING system

The best I can explain: Hydraulic ash handling system is more suitable large thermal plants since its ash carrying capacity is considerably large. And also it has ability to DISSOLVE the ash in the water which makes its capacity large. It also has lots of advantages it is clean, DUST FREE and no noise is produced. The water USED can be recycled only for limited amount of times.

The correct option is (b) Railways

For EXPLANATION: We do know shipways are cheaper. But we need ANOTHER MODE of transport to transfer that coal to the plant area. But in case of railways the TRACKS can be made to directly pass through the plant. Hence the RAILWAY is more economical compared to any other means of transport.

The correct OPTION is (a) 1/21 [(H2/2) + (CO/2) + 2CH4 + 3C2H4] m^3/m^3 of FUEL

Easiest EXPLANATION: Volumetric analysis of fuels hydrogen, carbon monoxide, methane, ethane, carbon dioxide and nitrogen is done and required minimum AMOUNT of oxygen is found for one m^3 of GASEOUS fuel:

O2 required/m^3 of fuel = 1/100[(H2/2) + (CO/2) + 2CH4 + 3C2H4] m^3

As atmospheric air contains 21% of O2 by volume, minimum air required t burn one m^3 of gaseous fuel is given by,

Minimum volume of air required (cm^3/m^3 of fuel):

= 1/100 [(H2/2) + (CO/2) + 2CH4 + 3C2H4] 100/21

= 1/21 [(H2/2) + (CO/2) + 2CH4 + 3C2H4] m^3/m^3 of fuel.

Correct answer is (b) Alcohol

Best explanation: Alcohol is an artificial fuel OBTAINED from vegetable matter by fermentation process. It is USED in many chemical processes.The FIRST four aliphatic alcohols (methanol, propanol, ethanol and BUTANOL) are of interest as fuels because they can be synthesized chemically or biologically. The general chemical formula for alcohol fuel is CnH2n+1OH.

Correct option is (a) Distillation

The best explanation: The IMPURITIES PRESENT in the crude oil are eliminated by the process of refining oil by distillation. It is based on the principle that BOILING points of various hydrocarbons increase with an increase in molecular weight and when distilled, the crude oil is separated into gasoline, KEROSENE, fuel oil or reduced crude oil.

The correct OPTION is (a) They produce lot of smoke

The explanation: Solid fuels tend to produce lot of smoke because they have large percentage of ASH CONTENT. They are also brittle in nature and they contain some amount of ash in it when they are in ground. DUE to their brittleness, it is common nature of solid fuels that they break into pieces while mining and transporting and form ash.

The correct choice is (b) Carbon steel

For explanation I would say: The STEAM generated in the BOILER is superheated in SUPER heater TUBES made of carbon steel for operating at a steam temperature of up to 950°F and carbon molybdenum steel for operating at steam temperature of 1050°F and stainless steel for operating temperature of 1200°F. The tubes of super heater have an outside diameter which ranges from 25mm to 64mm.