2nd Class Power Engineering (2A3) Practice Exam

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• Which of the following is NOT a method for removing dissolved metals from water?
• What is the average thermal efficiency of a supercritical plant?
• What temperature should mixed beds be cooled below for proper operation?
• How does the quantity of fluid pumped by a centrifugal pump change with impeller speed?
• To control the effect of acid corrosion at high pressures, what is maintained in a congruent phosphate program?
• What should be maintained if inert gas, such as nitrogen, is used in the boiler during dry lay-up?
• How can foaming be prevented in a boiler?
• What is the purpose of expansion joints in relation to boiler casings?
• What typically happens to the power needed to drive a centrifugal pump when the impeller speed is doubled?
• What is needed for calculating the heat balance of a steam plant?
• How does the heat release rate of oil-fired furnaces compare to that of coal-fired furnaces?
• What materials are used to make mechanical seal rings?
• What type of water treatment is commonly performed in once through cooling water systems?
• What is the primary function of oxygen scavengers in water treatment?
• Why can surface condensers be classified as deaerators?
• What type of liquids can reciprocating pumps handle?
• What can cause a sudden slug of water to be entrained with steam, known as priming?
• What is the main mechanism by which chelates prevent scale formation?
• What is one primary use for ceramic fibres?
• How does increasing boiler pressure affect phosphate solubility?
• What construction method is commonly used for water-cooled division walls?
• Which aspect must be considered when designing a boiler to ensure efficiency?
• What is the maximum acceptable concentration of total coliform bacteria in drinking water?
• What is the function of circulation pumps in high-pressure boilers?
• What is misting in boiler systems?
• What is the main purpose of a deaerating heater?
• What type of chemicals are modern sludge conditioners primarily made of?
• How does the concentration of metals in a cooling tower compare to makeup water?
• What advantage does membrane treatment have in removing colloidal silica?
• What is the role of chemical coagulating agents in emulsion breaking?
• What is an attemperator primarily used for?
• What are effective chemicals used to combat CO₂ corrosion?
• What is the purpose of oxygen treatment in a boiler system?
• Which of the following systems is commonly used to ensure a minimum flow rate through a pump at a constant speed?
• How does the constant pressure design of OTSG boilers typically operate?
• What is a characteristic of the direct contact attemperator?
• What is the maximum temperature of the boiler metal during a hydrostatic test?
• What is an advantage of chemical cleaning compared to mechanical cleaning?
• At what pH range is coagulation most effective?
• What characteristic of insulation materials is critical for maintaining boiler performance?
• What is an effective way to remove color from water containing organic materials?
• Which of the following is NOT a characteristic of passivating inhibitors?
• What is coagulation in the context of water treatment?
• Why do coal-fired furnaces need to be larger than gas or oil-fired furnaces?
• How does water emulsified in oil behave when mixed with water?
• Where is the final evaporator located in a once-through boiler?
• What occurs when the valve disc in a safety valve is worn?
• How quickly can once-through boilers be started up?
• What is an advantage of using an expeller in a sealing arrangement?
• What removal method is applicable for nickel in water treatment?
• Why is it crucial to deaerate water before adding pure oxygen in oxygen treatment?
• What is the maximum allowable temperature of the flue gas during a boiler dry lay-up?
• What condition can lead to foaming in boilers?
• What is one major reason why it is important to vent all air out of the seal housing?
• What type of heat transfer does a regenerative air heater utilize?
• How much chlorine is contained in sodium hypochlorite?
• How many combustion zones are specified for black liquor boilers?
• At what residual level of sodium sulphite is sufficient to control oxygen variations in the boiler?
• What is the recommended material and amount for moisture absorption during a boiler dry lay-up?
• What does BOD stand for in water treatment?
• What does the standard condition for comparing boilers involve converting?
• What defines an emulsion?
• What component of a boiler is usually the last stage for heat recovery?
• By how much does steam generator efficiency increase for every 5.5℃ to 6℃ rise in feedwater temperature?
• What minerals are primarily responsible for scale formation in boilers?
• What is the minimum temperature for performing a hydrostatic test on a boiler?
• What role does the rifling in boiler tubes serve?
• What is defined as "top dryness" in a boiler system?
• What is the temperature handling capability of high temperature plastic insulation?
• Which type of polymer creates negative sites when dissolved in water?
• What is a major disadvantage of a controlled circulation HRSG?
• When would a membrane wall with studs and a layer of refractory be used?
• If packing wear is excessive but the shaft sleeves are not worn, what can that indicate?
• What is typically the maximum outlet temperature of the economizer?
• What is the safe pH range for boiler water?
• What is a significant disadvantage of spiral tube walls?
• What is the maximum allowable rate of temperature change for components with rolled tube joints in a steam boiler?
• At what temperature should ducting be insulated?
• Flocculants used in water treatment can be classified into how many groups?
• Why are superheater tubes typically of small diameter?
• Why is it essential to oversize a superheater when using a spray desuperheater?
• What design consideration is important for furnace enclosures?
• What is the typical water temperature during the circulating method of chemical cleaning?
• Which of the following is NOT one of the three most common types of filters?
• What method can effectively reduce chromium in water?
• What is the typical thickness of block insulation on steam drums, mud drums, and headers?
• What type of pump is typically a single stage centrifugal pump with flat-bladed impellers?
• What distinguishes circulating fluid bed boilers from bubbling fluid bed boilers?
• What natural substance is commonly referred to as the "universal solvent"?
• What is defined as the element where the change of state from water to steam takes place?
• Which of the following best defines steam purity?
• What is the maximum acceptable concentration of oxygen in boiler water?
• Which of the following chemicals is commonly used in a phosphate program?
• How can delignification be controlled?
• Which of the following conditions favors the leaching of silica into water sources?
• What is notable about the heating capabilities of gas-fired furnaces?
• What process involved in filtration removes particles based on size?
• What factor influences the larger furnace volume for high-slagging lignite coal?
• What happens to metals at extremely high temperatures due to scale?
• What does an equilibrium phosphate program help prevent?
• What is the characteristic of oil emulsified in water?
• What pressure is used for performing a hydrostatic test?
• Which of the following is NOT one of the five fundamental requirements for boiler design?
• What is one of the advantages of forced circulation in boilers?
• What is another name for a lantern ring in mechanical seals?
• At what boiler pressure does silica begin to vaporize into steam?
• What is the recommended method for correcting pH levels in water treatment?
• What is one advantage of using polymers for coagulation in water treatment?
• What happens to the discharge flow of centrifugal pumps when the discharge head increases?
• What is the concentration of the regeneration fluid for a hydrogen zeolite softener?
• What type of circulation do most horizontal gas flow HRSG boilers use?
• What does the lime-soda softening process primarily precipitate?
• What type of materials can be used for the mating ring in mechanical seals?
• At what concentration in the steam does silica start to cause problems?
• What is the consequence of weak black liquor in combustion?
• Which precaution should be taken before starting a pump with a mechanical seal?
• What is the classification of slimicides or microbiocides?
• In which fluidized bed design does continuous circulation of solids occur?
• What type of construction can nearly ensure airtight conditions for division walls?
• What size of coal can typically be burned in a fluidized bed boiler?
• What is a major disadvantage of using ammonia in boiler systems?
• What is a common effect of overfeeding polymers in a flocculation process?
• What happens when the pH level in steam exceeds 9.0?
• In what unit are steam generators typically rated for turbo-alternators?
• What is a key factor that influences natural circulation in a boiler?
• What is a reason for using a reheater in a steam cycle?
• By how much can chlorine demand decrease from summer to winter?
• What is one common cause of foaming in a boiler system?
• What is defined as a heavy metal?
• Which type of attemperator features loop tubes in its design?
• What happens if "top dryness" becomes excessive?
• What is one disadvantage of using sodium sulphite in high pressure boilers?
• What should be done before testing a pump for blockages?
• What is the maximum temperature differential between feedwater and the metal during boiler drying?
• What must be ensured to minimize heat loss in a boiler setting?
• What are the two types of iron oxide found in boiler water?
• Which of the following classifies cooling water systems?
• Which of the following correctly defines Chemical Oxygen Demand (COD)?
• Which method calculates the output rating of a boiler based on square meters of heating surface?
• What is reduced when using expellers in sealing applications?
• What should be done experimentally when using an equilibrium phosphate program?
• What is the main risk associated with excessive foaming in a boiler?
• What is the typical water temperature during the soak method of chemical cleaning?
• What is the recommended water velocity in a gravity separator?
• Which two volatile amines are commonly used in boiler systems?
• What safety concern arises when water interacts with molten smelt?
• What does the strong anion exchanger accomplish in a treatment system?
• What are steam-flood boilers also known as?
• What type of solution is an indicator, characterized by a color change?
• Will anion exchangers remove carbonic acid?
• What is the effect of water temperature on particle sedimentation rates?
• What chemical is commonly used to remove deposits from high-pressure boilers?
• How do chelates work in boiler systems?
• Which factor does NOT affect flow resistance?
• How far can positive displacement pumps self-prime under perfect conditions?
• What effect does an increase in the impeller diameter have in a centrifugal pump?
• Why are specially designed seals important in pumps for controlled circulation boilers?
• How is lead predominantly removed from water?
• What can sodium sulphate break down into that contributes to condensate return corrosion?
• What could happen if trapped water beneath scale in a boiler continues to boil?
• How much water is typically evaporated in the radiant evaporator section of a once through boiler?
• Which method is often used to remove organic matter from water?
• What is the definition of a mho in electrical engineering?
• The purpose of the isokinetic sampling nozzle is to:
• What principle describes the method of heat transfer in a recuperative air heater?
• What type of gauge glass should be used during the dry out process, and why?
• What are steam generators often rated in terms of?
• Which type of pump generally has a greater capacity?
• Which type of pump uses a positive displacement mechanism?
• What is a potential consequence of scale sloughing off when a boiler is restarted?
• What is the primary purpose of flocculation in water treatment?
• What is one of the advantages of using a continuous chemical feed in a boiler system?
• What is the function of an indicator in water testing?
• What percentage of the heat transfer area is typically made up of water walls, superheater, and reheater sections?
• What is the first step in the process of removing emulsions from water?
• At what pressure are natural circulation boilers typically limited?
• How does steam temperature change with load in a radiant superheater?
• In a once-through boiler, how much water is typically evaporated in the radiant evaporator?
• If a pump has to work on a suction lift, what is typically installed on the suction line?
• How much heat is typically transferred to the boiler walls, superheater, and reheater sections?
• What recovery rate can be expected from an EDI system?
• How much flocculant is generally recommended for use in treatment processes?
• What type of impellers are used to counteract axial thrust on large capacity, centrifugal pumps?
• What defines a waste heat boiler?
• What are the two forms of ammonia commonly added to boiler water?
• Which of the following coagulants is most commonly used for low to medium turbidity?
• What is the maximum temperature limit for mineral wool blankets?
• How do adsorption inhibitors function to prevent corrosion?
• At what pressure should the drum vents be opened during a prolonged shutdown to prevent vacuum formation?
• Which insulation material can handle the highest temperatures?
• How large should the flow strainer be on the suction line of a pump?
• Which of the following best describes chelate treatment compared to phosphate treatment?
• At saturation temperature, how are all gases present in the solution?
• In electro-deionization (EDI), what is generated for continuous regeneration?
• How do filming amines protect metal surfaces in boiler systems?
• At what temperature can cation resin withstand condensate?
• What is a primary advantage of a once-through boiler?
• What is a limitation of rotary pumps?
• What is the optimal pH range for achieving the best results with a phosphate program?
• How are suspended solids primarily removed from water?
• What is the order of membrane processes from largest to smallest impurity size allowed through?
• What is the direction of gas flow in an economizer?
• Which type of pump is commonly used in large controlled circulation boilers?
• How are large steam generating units typically supported?
• Which insulation material is generally used for temperatures above 1040℃?
• What temperature range does fluidized bed combustion occur?
• What is the rate of Quicklime recommended for moisture absorption per cubic meter of boiler volume?
• What chemicals are primarily used in the hot lime - hot phosphate process?
• What is the difference between sterilization and disinfection of water?
• What is the purpose of screen tubes in a superheater section?
• What is the purpose of adding lime (CaCO₃) to the bed in fluidized bed combustion?
• What method is used to remove phosphate from water?
• In a travelling grate system, what percentage of the combustion air is typically fed from the bottom?
• What type of materials do humic substances fall under?
• What typically causes caustic corrosion in boilers?
• How do gas-fired furnace designs differ from oil-fired designs?
• What does NTU stand for in water quality measurement?
• How is ozone typically created on site for treatment purposes?
• What material is typically preferred for the components of a superheater?
• What happens to carbonic acid in a degasifier/decarbonator at atmospheric pressure?
• How does a hydrogen zeolite softener differ from a sodium zeolite softener?
• What is the typical time limit for stocking reagents?
• What is the optimum temperature for bitumen recovery by steam injection?
• What is the structure of a polymer?
• Why might a system use both a weak and strong ion exchanger?
• What additional agent is commonly used with ammoniated citric acid to enhance its effectiveness?
• Why does rapid pH adjustment in water treatment pose a risk?
• How effective is the hot process lime-soda softener in removing hardness?
• At what pressure differential does a pressure filter typically get backwashed?
• What is the primary function of passivating inhibitors?
• What type of deposit does scale leave on heating surfaces?
• How much can boiler efficiency increase by using an air heater?
• Which equipment is essential in a steam generating unit?
• Which type of furnace requires the largest size?
• What do calcium and magnesium ions form when a zeolite softener is regenerated?
• Where is pitting corrosion most commonly observed in a boiler system?
• What type of reaction primarily occurs in cation exchangers that produces carbonic acid?
• What is a boiling evaporator primarily used for?
• What causes water discoloration due to decaying vegetation?
• What is the factor of evaporation?
• What is the effect of chlorine residuals above 1 mg/l and a pH above 8.0?
• What happens to the impellers if low flow and high temperatures persist in a pump?
• How do the power requirements of axial-flow and mixed-flow pumps change at low capacity?
• When performing a hydrostatic test, when should the gag be installed on the safety valve?
• What is the effect of sodium bicarbonate in boiler water?
• What does the circulation ratio refer to?
• What type of parts must be removed during a chemical cleaning?
• What is one of the main advantages of a membrane wall in a furnace?
• What are the two general classes of forced circulation boilers?
• What is a characteristic of centrifugal pumps?
• Which factor does NOT affect the time taken for sedimentation of particles?
• Which factor is influenced by the type of fuel being used in a boiler?
• What is one variable that a boiler setting must withstand?
• What is one method for smoothing the flow from a reciprocating pump?
• How does a flash evaporator operate?
• What is an advantage of a "non-pusher" seal over a "pusher" seal?
• What is affected by the tube diameter and fluid velocity in a boiler system?
• What does the magnetite layer do in boiler systems?
• What is a major characteristic of bubbling fluidized bed boilers?
• What happens to the power requirement of a radial-flow centrifugal pump when throttling the discharge?
• What is the main operational characteristic of full sliding pressure design in OTSG?
• What encompasses the many combinations of heating surfaces like water walls and economizers?
• What is the main purpose of a condensate polishing system?
• Which of the following is NOT an alternative name for a heat recovery steam generator (HRSG)?
• What pressure range is sodium nitrate used for inhibiting embrittlement in boilers?
• What components are typically included in the "boiler setting"?
• Which layer in a multi-media filter is responsible for filtering out the largest particles?
• Which of the following is a type of mechanical carryover in a boiler?
• In the process of coagulation, what are the tiny visible particles called?
• What is one of the drawbacks of the shell type attemperator?
• What is one of the main roles of a deaerator?
• What is the primary function of ammonia in boiler water treatment?
• What is the main purpose of the heat recovery system in cogeneration?
• What is sodium sulphite commonly used for in boiler water treatment?
• What may occur if a pump is run below the minimum flow rate?
• What main effect does increasing the speed of a pump have on the allowable inlet pressure?
• What type of films do precipitating inhibitors form?
• What is the boil out pressure for boilers operating at 1400 kPa or less?
• Which type of pump can be an alternative in controlled circulation boilers aside from centrifugal pumps?
• Which chemical is commonly used to inhibit embrittlement in boilers?
• What material is mineral wool primarily made from?
• What special design feature may be found in the tubes of a supercritical boiler?
• Which parameter varies with the cube of the impeller diameter in a centrifugal pump?
• Which device is used to treat fuel gas in a boiler system?
• What is removed during the chemical treatment of emulsified oil?
• What is the principle behind electrodialysis?
• What is caustic embrittlement?
• What is a typical procedure if a safety valve is suspected to be damaged during a hydrostatic test?
• What is the first step in the clarification process that must be accommodated by equipment?
• What is the main effect of filming amines in high-temperature boiler systems?
• What is a potential consequence of sustained low flow and high temperature in a pump?
• What is colloidal silica?
• Which component in a mechanical seal typically acts on the seal face?
• What is one advantage of using curved or streamlined baffles in a boiler?
• What is one of the main advantages of once-through steam generators over traditional designs?
• What does the thermal sleeve in a direct contact attemperator help to prevent?
• What is the primary function of the boiler casing?
• What is a standard treatment to prevent embrittlement at pressures below 6200 kPa?
• What is the expected quality of effluent when using organic emulsifiers compared to inorganic coagulants?
• What type of control does a drum type attemperator provide?
• Why is upward flow of water in an economizer preferred?
• What is a rotating seal also known as?
• What are the different forms of chlorine available for treatment?
• What type of casing is normally used for pressures above 10,000 kPa?
• What distinguishes a mechanical seal designed for high speed centrifugal pumps?
• What is a common method to prevent scale formation in boilers?
• What type of baffles causes gases to flow at right angles to the tube length?
• What are the two classes of forced circulation boilers?
• At what pH level is chlorine most effective?
• Which method is used for the removal of zinc from water?
• What percentage of the total heat transfer area of a boiler do the economizer and air heater sections account for?
• Which chemical is often used as a replacement for chlorine?
• What bacteria is considered the greatest trouble in potable water treatment?
• Which of the following is NOT a process used for lime-soda softeners?
• Which method can be used to prove a bent tube is clear of obstruction?
• What is the name of the nozzles used for sampling steam purity?
• Which of the following is a key factor in the phosphate program's effectiveness?
• What must be present for caustic embrittlement to occur?
• Which coagulant is commonly used upstream of demineralization or reverse osmosis?
• What problem can arise from injecting too much phosphate into the boiler?
• What is the primary purpose of sludge conditioners/dispersants in a boiler?
• What happens during the second step of the Kraft process after wood chips are cooked?
• What is a key factor to consider in the design of a superheater?
• When is a congruent phosphate program ideal for use?
• How does specific conductance relate to actual TDS in water?
• Which type of filtration involves the removal of free residual chlorine?
• Which method is more effective for removing large amounts of oxygen from water?
• What does mass flow measure in a boiler system?
• What is the minimum operating pressure at which sodium ions must be removed?
• In a multi-media filter, which media is the largest and least dense?
• In which condition would well water typically contain more silica than surface waters?
• What issue arises with phosphate hideout at boiler pressures above 17,200 kPa?
• Where must the condensate pump vent lead to?
• Which chemical is primarily used for internal treatment at higher pressures in boilers?
• What type of refractory is commonly used around inspection and burner openings?
• What effect does scale have on heat transfer in a boiler?
• Which of the following compounds is a weak acid and commonly acts as a color indicator?
• How do convection superheaters respond to increased load in terms of steam temperature?
• When should chemicals be added to the water during boiler drying?
• Where does scale most commonly form in a boiler?
• What is the most common type of solid fuel that is burned in boilers?
• What is a common requirement for once-through steam generators concerning feedwater?
• What material are baffles often constructed of if they allow gases to flow between them?
• What is the function of a degasifier/decarbonator?
• Which of the following is NOT a common oxygen scavenger?
• How do dissolved solids typically affect the clarity of water?
• What key feature must boiler settings possess?
• What is a common material for the bed in a fluidized bed boiler?
• What type of filter would you use to filter out the smallest particles, including bacteria?
• Iron and copper compounds in the system are often a result of which process?
• What is the primary purpose of superheating steam in a turbine?
• What is the typical thermal efficiency range for subcritical plants?
• What is a potential risk associated with excessive use of chelates in boiler treatment?
• What is the key difference in steam pressure between a superheater and a reheater?
• How much total steam load can a steaming economizer generate at full boiler load?
• What characteristic do controlled circulation HRSGs provide regarding circulation?
• What is a characteristic of medium-sized furnaces used for low-slagging lignite coal?
• At what pressure is forced circulation typically preferred?
• What is one design parameter for oil-fired furnaces?
• Which of the following is a disadvantage of zeolite softeners?
• Which of the following is an advantage of once-through steam generators?
• What is the first step in the Kraft process of pulp production?
• What does carryover refer to in boiler systems?
• How can silica be effectively removed from water?
• Which of the following factors is NOT typically considered when selecting a pump?
• Which type of economizer is more commonly used?
• Which chemical is known to convert carboxyl ions in surfactants to carboxyl acid?
• What is the typical purge airflow for multiple burner units in a boiler?
• What does cogeneration refer to?
• What is calcium silicate block primarily used for?
• In open recirculating systems, what is the typical concentration of cooling water?
• What is simmer, in the context of safety valves?
• At what pressure should drum vents be closed when putting a boiler into service?
• What airflow percentage should be maintained for a boiler during a prolonged shutdown?
• What indicates that strong acid cation exchangers may need regeneration?
• Which disadvantage is associated with once-through boilers?
• What is the relationship between the head produced by a centrifugal pump and impeller speed?
• What is one advantage of closed recirculating systems?
• What chemical can be added to boiler water to increase pH?
• How many kilowatts is equivalent to one boiler horsepower?
• What is the typical circulation ratio for a natural circulation HRSG?
• What type of pump is typically required above 14,000 kPa?
• How can caustic corrosion be prevented in lower pressure boilers?
• What are the two most common types of chemical feed pumps?
• What concentration of sulphuric acid is typically used for strong cation demineralization?
• What is the maximum allowed steam purity for use in turbines?
• A controlled circulation boiler is typically used for what pressure range?
• What controls the amount of water flowing into the steam generating tubes in a controlled circulation boiler?
• What are the two most common types of chelates?
• What are the characteristics of a standard cooling water pump?
• What negative effect does oil have on boiler feedwater?
• What defines a reagent in the context of water treatment?