4AE3 U12 C1 Review
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Questions and Answers

What is the primary function of the heat exchanger in a boiler?

  • To provide oxygen for combustion
  • To regulate the burner
  • To convert chemical energy to heat energy
  • To transfer heat to the boiler water (correct)

    • What is the term for the burning or rapid oxidation of a fuel that produces light and heat?

  • Combustion (correct)
  • Heat transfer
  • Oxidation reaction
  • Energy conversion

    • Why is it necessary to evaluate fuels and determine the best way to prepare and burn them?

  • To minimize the maintenance of the boiler
  • To ensure complete combustion and prevent waste (correct)
  • To reduce the cost of fuel
  • To increase the efficiency of the boiler

    • What is a potential hazard of incomplete combustion?

    <p>All of the above</p> Signup and view all the answers

    What is a key factor in optimizing energy conversion in boilers?

    <p>Understanding the chemical and physical properties of fuels</p> Signup and view all the answers

    What is the primary goal of understanding the combustion process in boilers?

    <p>To ensure safety and efficiency</p> Signup and view all the answers

    What is a common characteristic of gaseous fuels like natural gas?

    <p>Simple molecular composition</p> Signup and view all the answers

    What is the purpose of oxygen in the combustion process?

    <p>To facilitate combustion</p> Signup and view all the answers

    What is the acronym NOCASH used for?

    <p>To remember the base fuel components</p> Signup and view all the answers

    What is the result of hydrogen combining with oxygen in the combustion process?

    <p>Production of water</p> Signup and view all the answers

    Why is oxygen in a fuel used as an indicator of the amount of hydrogen unavailable for combustion?

    <p>Because oxygen is present in the form of water</p> Signup and view all the answers

    What is the non-combustible component of a fuel that remains as a residue after combustion?

    <p>Ash</p> Signup and view all the answers

    Why is it important to limit the release of NOX?

    <p>Because it is a pollutant</p> Signup and view all the answers

    What is a characteristic of biomass fuels compared to hydrocarbon-based fuels?

    <p>Higher percentage of nitrogen</p> Signup and view all the answers

    What is the source of biomass fuels?

    <p>Forestry and agricultural industries</p> Signup and view all the answers

    What is the typical percentage of nitrogen in wood waste?

    <p>0.25%</p> Signup and view all the answers

    What is the primary concern regarding the reaction products of combustion?

    <p>The release of NOX</p> Signup and view all the answers

    Why is nitrogen bound within the chemical makeup of the fuel a concern?

    <p>It reacts with oxygen to produce NOX</p> Signup and view all the answers

    What is the purpose of increasing the fuel to air ratio in combustion?

    <p>To lower the potential for NOX production</p> Signup and view all the answers

    What is the result of complete combustion of the fuel in the furnace?

    <p>The release of heat energy is maximized</p> Signup and view all the answers

    What are the three conditions necessary for complete combustion, besides adequate air?

    <p>Time, temperature, and turbulence</p> Signup and view all the answers

    What is the result of incomplete combustion?

    <p>The products of combustion can react further with oxygen and release more heat</p> Signup and view all the answers

    What is the equation for the complete combustion of sulfur?

    <p>S + O2 → SO2 + Heat</p> Signup and view all the answers

    Why is carbon monoxide a concern in combustion?

    <p>It is a combustible compound</p> Signup and view all the answers

    What is the purpose of treating combustion gases with chemicals?

    <p>To react with NOX and produce other compounds</p> Signup and view all the answers

    What is the primary factor governing the design of a new combustion system?

    <p>Environmental regulations</p> Signup and view all the answers

    What is the result of carbon monoxide combining with more oxygen before leaving the furnace?

    <p>The formation of carbon dioxide with an additional release of heat</p> Signup and view all the answers

    What is the main concern when considering incomplete combustion?

    <p>The formation of carbon monoxide</p> Signup and view all the answers

    What is the purpose of supplying excess air to the furnace?

    <p>To ensure that all particles of fuel are exposed to oxygen</p> Signup and view all the answers

    What is the result of incomplete combustion of carbon in the fuel?

    <p>The production of black smoke and soot</p> Signup and view all the answers

    What is the effect of sulfur dioxide discharged into the atmosphere?

    <p>It contributes to air pollution, including acid rain</p> Signup and view all the answers

    What is the percentage of oxygen in the air by volume?

    <p>21%</p> Signup and view all the answers

    What is the term for the amount of air required for complete combustion?

    <p>Theoretical air</p> Signup and view all the answers

    Why is the formation of free hydrogen undesirable?

    <p>It represents a waste of fuel and a loss of heating value</p> Signup and view all the answers

    What determines the amount of excess air required for proper combustion?

    <p>All of the above</p> Signup and view all the answers

    What is the result of the combustion of sulfur in the presence of water?

    <p>The production of corrosive acids</p> Signup and view all the answers

    What is the primary effect of excess air on boiler efficiency?

    <p>It carries away heat and lowers boiler efficiency.</p> Signup and view all the answers

    What is the purpose of calculating the theoretical air requirement for a fuel?

    <p>To determine the amount of oxygen required to completely combust the fuel.</p> Signup and view all the answers

    What is the unit of measurement for the theoretical air requirement?

    <p>m3 per kg of fuel</p> Signup and view all the answers

    What is the molar ratio of carbon to oxygen in the combustion reaction?

    <p>1:1</p> Signup and view all the answers

    What is the purpose of step 2 in calculating the theoretical air requirement?

    <p>To convert the mass of each element to moles.</p> Signup and view all the answers

    What is the volume of oxygen occupied by one mole of any gas at standard temperature and pressure?

    <p>22.4 L</p> Signup and view all the answers

    What is the result of incomplete combustion in a furnace?

    <p>The formation of carbon monoxide and free hydrogen.</p> Signup and view all the answers

    What is the primary factor that determines the theoretical air requirement for a fuel?

    <p>The chemical composition of the fuel.</p> Signup and view all the answers

    What is the purpose of step 4 in calculating the theoretical air requirement?

    <p>To convert the moles of oxygen required to a volume of oxygen.</p> Signup and view all the answers

    What is the effect of reducing excess air in a furnace?

    <p>It reduces the power required for forced and induced draft fans.</p> Signup and view all the answers

    What is one of the regulated parameters for RDF emission management?

    <p>A minimum temperature of 1000°C</p> Signup and view all the answers

    What is the purpose of a secondary air supply in RDF combustion?

    <p>To ensure efficient mixing between burning waste and incoming air</p> Signup and view all the answers

    Why is it necessary to maintain a minimum oxygen level at the outlet in RDF combustion?

    <p>To minimize quenching or mixing problems</p> Signup and view all the answers

    What is the CCME's role in RDF management?

    <p>To provide guidelines and regulations on the management of RDF and its emissions</p> Signup and view all the answers

    Why is carbon monoxide a concern in RDF combustion?

    <p>It is a pollutant that can have negative effects on air quality</p> Signup and view all the answers

    What is the percentage of oxygen in air by volume?

    <p>21%</p> Signup and view all the answers

    What is the ratio of total air to oxygen required to theoretically combust 100 kg of fuel?

    <p>4.76</p> Signup and view all the answers

    What is the unit of measurement for theoretical air in an alternative calculation?

    <p>kg/kg</p> Signup and view all the answers

    What is the molar ratio of carbon to oxygen in combustion?

    <p>1:1</p> Signup and view all the answers

    What is the volume of one mole of any gas at standard temperature and pressure?

    <p>22.4 L</p> Signup and view all the answers

    What is the purpose of excess air in combustion?

    <p>To ensure complete combustion</p> Signup and view all the answers

    What is the primary component of flue gas that comes from combustion air?

    <p>N2</p> Signup and view all the answers

    What is the term for the nitrogen oxides produced during combustion?

    <p>NOX</p> Signup and view all the answers

    What is the significance of the difference in theoretical air requirements between solid and liquid fuels?

    <p>It affects the air handling equipment requirements</p> Signup and view all the answers

    What is the purpose of analyzing the flue gas in combustion?

    <p>To determine whether combustion is complete</p> Signup and view all the answers

    What is the primary source of nitrogen that enters a furnace?

    <p>Combustion air</p> Signup and view all the answers

    Why is it important to reduce excess air to a minimum in the combustion process?

    <p>To reduce the amount of heat carried away by the nitrogen</p> Signup and view all the answers

    What determines the ideal amount of excess air required for complete combustion?

    <p>Both composition and condition of the fuel, and method used for burning the fuel</p> Signup and view all the answers

    What is a consequence of a shortage of combustion air in a boiler room?

    <p>Incomplete combustion of the fuel</p> Signup and view all the answers

    What is the purpose of outside air supply openings in boiler rooms?

    <p>To permit satisfactory combustion</p> Signup and view all the answers

    What is the primary component of coal that is not combustible?

    <p>Ash</p> Signup and view all the answers

    What is the main difference in the analysis of solid fuels compared to liquid or gaseous fuels?

    <p>More frequent analysis</p> Signup and view all the answers

    What is the term used to describe the combustion product of sulfur in coal?

    <p>Sulfur dioxide</p> Signup and view all the answers

    What is the purpose of proximate analysis of solid fuels?

    <p>To measure the moisture, fixed carbon, volatile combustible material, and ash content of a fuel</p> Signup and view all the answers

    Which type of fuel is wood byproduct considered?

    <p>Carbon-neutral</p> Signup and view all the answers

    Why is coal recognized as being a significant contributor to atmospheric pollution?

    <p>Because it produces the greatest amount of atmospheric pollution</p> Signup and view all the answers

    What is the purpose of crushing wood pieces to produce hog fuel?

    <p>To produce a fuel of varying sizes and shapes</p> Signup and view all the answers

    What is the purpose of ultimate analysis of solid fuels?

    <p>To determine the elemental composition of the fuel in percent by mass</p> Signup and view all the answers

    Which type of facility burns MSW in a single combustion chamber with excess air?

    <p>Mass Burning Facility</p> Signup and view all the answers

    What can cause the formation of 'hoar frost' on building air inlet screens?

    <p>Certain atmospheric conditions</p> Signup and view all the answers

    What is the benefit of burning MSW in terms of methane generation?

    <p>It reduces methane generation</p> Signup and view all the answers

    What is the term used to describe the materials that are sourced from grasses and straw?

    <p>Herbaceous fuels</p> Signup and view all the answers

    What is the purpose of mechanical methods in Refuse Derived Fuel Systems?

    <p>To shred incoming MSW</p> Signup and view all the answers

    Why are coal, oil, and gas considered more concentrated and easier to transport than wood?

    <p>They have a higher energy density</p> Signup and view all the answers

    What is the primary reason for the decline of wood as a fuel source?

    <p>The rise of coal, oil, and gas</p> Signup and view all the answers

    What is the primary purpose of understanding the combustion process in power engineering?

    <p>To optimize energy conversion and ensure safety</p> Signup and view all the answers

    What is the result of incomplete combustion in terms of energy efficiency?

    <p>Wasted fuel and energy</p> Signup and view all the answers

    Why is it necessary to evaluate the chemical and physical properties of fuels?

    <p>To understand the combustion process and optimize energy conversion</p> Signup and view all the answers

    What is the term for the rapid oxidation of a fuel that produces light and heat?

    <p>Combustion</p> Signup and view all the answers

    What is a potential hazard of incomplete combustion?

    <p>Explosion hazards</p> Signup and view all the answers

    Why is it important for Power Engineers to fully understand the combustion process?

    <p>To optimize energy conversion and ensure safety</p> Signup and view all the answers

    What is the primary reason for assuming that nitrogen in the air is non-reactive at combustion temperatures?

    <p>Because it is not a combustible element</p> Signup and view all the answers

    What is the main difference between gaseous fuels and liquid or solid fuels?

    <p>Gaseous fuels are simpler in molecular composition</p> Signup and view all the answers

    What is the purpose of the NOCASH acronym in fuel analysis?

    <p>To remember the base fuel components</p> Signup and view all the answers

    What is the result of the chemical combination of hydrogen and oxygen prior to combustion in a solid fuel?

    <p>The formation of water</p> Signup and view all the answers

    Why is ash considered a non-combustible component of a fuel?

    <p>Because it remains as a residue after combustion</p> Signup and view all the answers

    What is the primary reason for limiting the release of NOX in combustion?

    <p>To meet the terms of the plant environmental license</p> Signup and view all the answers

    What is the primary source of biomass fuels?

    <p>Forestry and agricultural industries</p> Signup and view all the answers

    What is the result of the combustion of hydrogen with oxygen in a fuel?

    <p>The formation of water</p> Signup and view all the answers

    What is the difference between fuel-based nitrogen and nitrogen in the air?

    <p>Fuel-based nitrogen is reactive, while nitrogen in the air is non-reactive</p> Signup and view all the answers

    What is the purpose of analyzing the moisture content of a fuel?

    <p>To determine the amount of hydrogen unavailable for combustion</p> Signup and view all the answers

    What is the primary reason why the release of NOX is of greatest concern?

    <p>It can lead to the formation of acidic compounds</p> Signup and view all the answers

    What is the purpose of treating combustion gases with chemicals?

    <p>To react with NOX and produce other compounds</p> Signup and view all the answers

    What is the result of incomplete combustion in a furnace?

    <p>The formation of carbon monoxide</p> Signup and view all the answers

    What is the primary factor that governs the design of a new combustion system?

    <p>Environmental regulations</p> Signup and view all the answers

    What is the purpose of ensuring complete combustion of the fuel in the furnace?

    <p>To release the greatest amount of heat energy</p> Signup and view all the answers

    What is the term used to describe the combustion products of sulfur?

    <p>Sulfur dioxide</p> Signup and view all the answers

    What is the result of the reaction between hydrogen and oxygen during complete combustion?

    <p>The formation of water vapour and heat</p> Signup and view all the answers

    What is the primary concern regarding the reaction products of combustion?

    <p>The release of NOX emissions</p> Signup and view all the answers

    What is the purpose of increasing the fuel to air ratio in combustion?

    <p>To lower the potential for NOX production</p> Signup and view all the answers

    What is the result of the reaction between carbon and oxygen during complete combustion?

    <p>The formation of carbon dioxide and heat</p> Signup and view all the answers

    What is the main reason for ensuring combustion processes are driven to completion?

    <p>To maximize the amount of energy removed from the fuel and meet efficiency targets</p> Signup and view all the answers

    What is the primary factor that determines the ideal amount of excess air required for complete combustion?

    <p>All of the above</p> Signup and view all the answers

    What is the result of the incomplete combustion of carbon in the fuel?

    <p>The formation of free carbon and black smoke</p> Signup and view all the answers

    Why is the formation of free sulfur undesirable?

    <p>Because it represents a waste of fuel and a loss of heating value</p> Signup and view all the answers

    What is the purpose of supplying excess air to the furnace?

    <p>To ensure that all particles of fuel are exposed to oxygen</p> Signup and view all the answers

    What is the effect of the sulfur dioxide discharged into the atmosphere?

    <p>It contributes to the production of acid rain</p> Signup and view all the answers

    What is the result of the combustion of carbon monoxide with more oxygen?

    <p>The formation of carbon dioxide and an additional release of heat</p> Signup and view all the answers

    Why is the formation of carbon monoxide a concern in combustion?

    <p>Because it represents a waste of fuel and a loss of heating value</p> Signup and view all the answers

    What is the term used to describe the amount of air required for complete combustion?

    <p>Theoretical air</p> Signup and view all the answers

    Why is it necessary to ensure that combustion processes are driven to completion?

    <p>To maximize the amount of energy removed from the fuel and meet efficiency targets</p> Signup and view all the answers

    What is the total volume of air required to theoretically combust 100 kg of the fuel, given the ratio of total air to O2 is 4.76?

    <p>1080.21 m3</p> Signup and view all the answers

    What is the primary factor governing the calculation of theoretical air requirement for a fuel?

    <p>Chemical composition of the fuel</p> Signup and view all the answers

    What is the molar ratio of hydrogen to oxygen in the combustion reaction?

    <p>4:1</p> Signup and view all the answers

    What is the volume of one mole of any gas at standard temperature and pressure?

    <p>22.4 L</p> Signup and view all the answers

    What is the molar ratio of hydrogen to oxygen in the combustion reaction of hydrogen?

    <p>4:1</p> Signup and view all the answers

    What is the purpose of calculating the theoretical air requirement for a fuel?

    <p>To determine the volume of air required for complete combustion</p> Signup and view all the answers

    What is the purpose of calculating the theoretical air requirement for a fuel?

    <p>To determine the amount of excess air required for proper combustion</p> Signup and view all the answers

    What is the result of multiplying the moles of oxygen required by the volume of one mole of oxygen (22.4 L/mol) in the calculation of theoretical air?

    <p>Theoretical air volume in liters</p> Signup and view all the answers

    What is the term for the amount of air required for complete combustion?

    <p>Theoretical air</p> Signup and view all the answers

    What is the element that reacts with oxygen in the combustion reaction with a molar ratio of 1:1?

    <p>Carbon</p> Signup and view all the answers

    What is the primary factor that determines the theoretical air requirement for a fuel?

    <p>The composition of the fuel</p> Signup and view all the answers

    What is the result of incomplete combustion in terms of energy efficiency?

    <p>Decreased energy efficiency</p> Signup and view all the answers

    What is the significance of the theoretical air requirement calculation?

    <p>It determines the amount of oxygen required for complete combustion</p> Signup and view all the answers

    What is the primary source of nitrogen that enters a furnace?

    <p>The combustion air</p> Signup and view all the answers

    What is the unit of measurement for the theoretical air requirement?

    <p>Cubic meters per kilogram of fuel</p> Signup and view all the answers

    What is the purpose of step 1 in calculating the theoretical air requirement?

    <p>To convert the percentage of combustible elements into mass</p> Signup and view all the answers

    What is the purpose of excess air in combustion?

    <p>To ensure complete combustion</p> Signup and view all the answers

    What is the effect of reducing excess air to a minimum in the combustion process?

    <p>It improves the efficiency of the combustion system</p> Signup and view all the answers

    What is the term for the nitrogen oxides produced during combustion?

    <p>NOX</p> Signup and view all the answers

    What is the primary reason for calculating the theoretical air requirement for a fuel?

    <p>To optimize the excess air percentage for the furnace</p> Signup and view all the answers

    What is the minimum temperature required to ensure the destruction of organics in RDF combustion?

    <p>1000°C</p> Signup and view all the answers

    What is the minimum retention time required after combustion has completed in RDF combustion?

    <p>More than one second at 1000°C</p> Signup and view all the answers

    What is the minimum oxygen level required at the outlet in RDF combustion to minimize quenching or mixing problems?

    <p>3 to 9% O2</p> Signup and view all the answers

    What is the purpose of ensuring efficient mixing between burning waste and incoming air in RDF combustion?

    <p>To ensure complete combustion of RDF</p> Signup and view all the answers

    What is the purpose of regulating the secondary air supply in RDF combustion?

    <p>To ensure efficient mixing between burning waste and incoming air</p> Signup and view all the answers

    What is the primary reason for reducing excess air to a minimum in the combustion process?

    <p>To minimize heat loss to the atmosphere</p> Signup and view all the answers

    What is the consequence of a shortage of combustion air in a boiler room?

    <p>Both a and b</p> Signup and view all the answers

    What is the purpose of proximate analysis of solid fuels?

    <p>To measure the moisture, fixed carbon, volatile combustible material, and ash content of a fuel</p> Signup and view all the answers

    What is the primary factor that determines the ideal amount of excess air required for complete combustion?

    <p>All of the above</p> Signup and view all the answers

    What is the result of incomplete combustion of carbon in the fuel?

    <p>Formation of soot</p> Signup and view all the answers

    What is the purpose of supplying outside air to boiler rooms?

    <p>To provide the amount of air required for complete combustion</p> Signup and view all the answers

    What is the significance of nitrogen in the combustion process?

    <p>It is a non-reacting gas that dilutes the oxygen in the combustion air</p> Signup and view all the answers

    What is the consequence of inadequate combustion air supply in a boiler room?

    <p>Poor heat transfer and increased fuel consumption</p> Signup and view all the answers

    What is the purpose of ultimate analysis of solid fuels?

    <p>To measure the elemental composition of the fuel in percent by mass</p> Signup and view all the answers

    What is the primary concern regarding the reaction products of combustion?

    <p>Formation of soot and other pollutants</p> Signup and view all the answers

    What is the primary component of coal that is combustible?

    <p>Carbon, hydrogen, and sulfur</p> Signup and view all the answers

    What is the term used to describe the hydrocarbons formed from the combination of hydrogen with some of the carbon in coal?

    <p>Volatile matter</p> Signup and view all the answers

    What is the primary advantage of using coal, oil, and gas over wood as a fuel source?

    <p>They are more concentrated and easier to transport</p> Signup and view all the answers

    What is the purpose of Refuse Derived Fuel Systems in Municipal Solid Waste combustion?

    <p>To separate out non-combustible materials</p> Signup and view all the answers

    What is the benefit of burning Municipal Solid Waste in terms of landfills?

    <p>It reduces the volume of solid waste destined for landfills</p> Signup and view all the answers

    What is the term used to describe the collective term for wood residues, bark, chips, and sawdust?

    <p>Hog fuel</p> Signup and view all the answers

    What is the primary concern regarding the combustion of sulfur in coal?

    <p>It produces sulfur dioxide, which contributes to air pollution</p> Signup and view all the answers

    What is the primary advantage of using biomass fuels over fossil fuels?

    <p>They are carbon-neutral</p> Signup and view all the answers

    What is the primary purpose of calculating the theoretical air requirement for a fuel?

    <p>To optimize the combustion process</p> Signup and view all the answers

    What is the primary component of coal that is considered an impurity?

    <p>Sulfur</p> Signup and view all the answers

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