From base load operation and from achieving best specific energy consumption point of view, which of the following compressors are suitable? a) Single stage reciprocating compressors b) Centrifugal compressors c) Two stage reciprocating compressor d) Multi stage reciprocating compressor

From base load operation and from achieving best specific energy consumption point of view, which of the following compressors are suitable? a) Single stage reciprocating compressors b) Centrifugal compressors c) Two stage reciprocating compressor d) Multi stage reciprocating compressor
by

1 Answer

Answer :

b) Centrifugal compressors
by

Related questions

From the point of lower specific energy consumption, which of the following compressors are suitable for part load operation? a) Two stage reciprocating compressors b) Centrifugal compressors c) Two stage screw compressor d) Single stage screw compressor

Description : From the point of lower specific energy consumption, which of the following compressors are suitable for part load operation? a) Two stage reciprocating compressors b) Centrifugal compressors c) Two stage screw compressor d) Single stage screw compressor

Last Answer : a) Two stage reciprocating compressors

Why inter-coolers are required for multi-stage reciprocating compressors?

Description : Why inter-coolers are required for multi-stage reciprocating compressors?  

Last Answer : The intercoolers reduce the temperature of air/gas discharged between stages. Ideally, the intake temperature at each stage should be the same as that at the first stage (referred to a perfect cooling), so that the volume of air to be compressed does not increase and hence reduced power consumption.

Which of the statement is “True” for centrifugal compressors? a) The compressor should not be operated at full load b) The compressor should be operated at shut off pressure c) The compressor should not be operated with inlet-guide vane control d) The compressor should not be operated close to the surge point

Description : Which of the statement is True for centrifugal compressors? a) The compressor should not be operated at full load b) The compressor should be operated at shut off pressure c) The ... operated with inlet-guide vane control d) The compressor should not be operated close to the surge point 

Last Answer : d) The compressor should not be operated close to the surge point

What is the effect of increase in altitude on the performance of single stage reciprocating compressors?

Description : What is the effect of increase in altitude on the performance of single stage reciprocating compressors? 

Last Answer : With the increase in altitude, there will be reduction in air pressure, which results in increase in compression ratio, leading to higher discharge temperature and reduced efficiency. 

What is a surge point and how do you prevent surging, in centrifugal compressors?

Description : What is a surge point and how do you prevent surging, in centrifugal compressors?

Last Answer : Surge point is the point on the performance curve where a further decrease inflow (typically in the region of 50-70 % of rated capacity) causes instability, resulting in a pulsating flow, ... to thrust reversals, or excessive vibration. Bypass valves advents are commonly used to prevent surging. 

List the advantages of keeping the discharge pressure for reciprocating compressors at minimum.

Description : List the advantages of keeping the discharge pressure for reciprocating compressors at minimum. 

Last Answer : Lower power consumption Less load on the piston rods and hence reduced maintenance costs Lower leakage losses

List the means of capacity control for reciprocating compressors.

Description : List the means of capacity control for reciprocating compressors. 

Last Answer : On/off control Load and unload control Multi-step control

What are the likely effects of using very cold water in intercoolers for reciprocating compressors?

Description : What are the likely effects of using very cold water in intercoolers for reciprocating compressors? 

Last Answer : Use of very cold water can result in condensation which may result in water entering the cylinder, thereby reducing valve life, accelerating wear and scoring of piston, piston rings and ... and cause rust which will result in abrasion during compressor operation and significantly reduce efficiency. 

Vertical type reciprocating compressors are used in the capacity range of _____ a) 50 – 150 cfm b) 200 – 500 cfm c) Above 10ooo cfm d) 10 – 50 cfm

Description : Vertical type reciprocating compressors are used in the capacity range of _____ a) 50 – 150 cfm b) 200 – 500 cfm c) Above 10ooo cfm d) 10 – 50 cfm 

Last Answer : a) 50 – 150 cfm

What are the limitations of a centrifugal compressor operation?

Description : What are the limitations of a centrifugal compressor operation? 

Last Answer : The major limitation of a centrifugal compressor is that is operates at peak efficiency at design point only and any deviation from the operating point is detrimental to its performance. When selecting ... at high pressure, with the consequent reduction in flow, the surge point is not reached.

Identify the correct statement for air compressors. a. For every 5.5oC drop in the inlet air temperature, the increase in energy consumption is by 2%. b. For every 4 oC rise in the inlet air temperature, the decrease in energy consumption is by 1% c. For every 4 oC rise in the inter air temperature, the increase in energy consumption is by 1% d. The energy consumption remains same irrespective of inlet air temperature

Description : Identify the correct statement for air compressors. a. For every 5.5oC drop in the inlet air temperature, the increase in energy consumption is by 2%. b. For every 4 oC rise in ... increase in energy consumption is by 1% d. The energy consumption remains same irrespective of inlet air temperature 

Last Answer : c. For every 4 oC rise in the inter air temperature, the increase in energy consumption is by 1% 

Which of the following type does Screw compressor belongs to? a) Positive displacementcompressor b) Dynamic compressors c) Both a & b d) None of the above

Description : Which of the following type does Screw compressor belongs to? a) Positive displacementcompressor b) Dynamic compressors c) Both a & b d) None of the above 

Last Answer : a) Positive displacementcompressor

What are the methods of capacity control in centrifugal air compressors?

Description : What are the methods of capacity control in centrifugal air compressors?  

Last Answer : Centrifugal compressors operate best at the design point. They are prone to surging at flow rates less than 50% of the rated capacity. The following types of controls are employed in ... variable speed drives to match compressor output to meet varying load requirements is by speed control 

The specific power consumption of non lubricated compressor compared to lubricated type is ____ a) Lesser b) Same c) Higher d) None

Description : The specific power consumption of non lubricated compressor compared to lubricated type is ____ a) Lesser b) Same c) Higher d) None 

Last Answer : c) Higher

The compressor capacity of a reciprocating compressor is directly proportional to __ a) Speed b) Pressure c) Volume d) All

Description : The compressor capacity of a reciprocating compressor is directly proportional to __ a) Speed b) Pressure c) Volume d) All 

Last Answer : a) Speed

The discharge temperature of two stage compressor compared to single stage one is ____ a) Lesser b) Same c) Higher d) None

Description : The discharge temperature of two stage compressor compared to single stage one is ____ a) Lesser b) Same c) Higher d) None  

Last Answer : a) Lesser

Can you explain how temperature of inlet air affects the energy consumption of an air compressor?

Description : Can you explain how temperature of inlet air affects the energy consumption of an air compressor?

Last Answer : As a thumb rule “for every 4 °C rise in inlet air temperature results in a higher energy consumption by 1% to achieve equivalent output”. Hence cool air intake leads to a more efficient compression.

Reduction in the delivery pressure of a Compressor working at 7 bar, by 1 bar would reduce the power consumption by a) 6 to 10 % b) 2 to 3 % c) 12 to 14 % d) None of the above

Description : Reduction in the delivery pressure of a Compressor working at 7 bar, by 1 bar would reduce the power consumption by a) 6 to 10 % b) 2 to 3 % c) 12 to 14 % d) None of the above

Last Answer : a) 6 to 10 %

The percentage increase in power consumption of a compressor with suction side air filter and with the pressure drop across the filter of 200 mmWc is ____ a) 1.0% b) 3% c) 2.4% d) 1.6%

Description : The percentage increase in power consumption of a compressor with suction side air filter and with the pressure drop across the filter of 200 mmWc is ____ a) 1.0% b) 3% c) 2.4% d) 1.6% 

Last Answer : d) 1.6%

For every 4°C raise in air inlet temperature of an air compressor, the power consumption will increases by_____ a) 2% b) 1% c) 3% d) 4%

Description : For every 4°C raise in air inlet temperature of an air compressor, the power consumption will increases by_____ a) 2% b) 1% c) 3% d) 4%

Last Answer : b) 1%

Give major classifications of compressors and the basic principle of its working.

Description : Give major classifications of compressors and the basic principle of its working.  

Last Answer : The major classifications of compressors are positive displacement and dynamic type. Positive displacement can be further divided in to (a) Reciprocating (b) Rotary. Dynamic compressors divided into Radial and ... increase the air or gas velocity, which is then converted to increase the pressure. 

The compression ratios for axial flow compressors are ____. a) Lesser b) Higher c) moderate d) None

Description : The compression ratios for axial flow compressors are ____. a) Lesser b) Higher c) moderate d) None 

Last Answer : b) Higher

Centrifugal compressors compared to reciprocating compressors (A) Require less space (B) Have quieter operation (C) Have lower operating costs (D) All (A), (B) and (C)

Description : Centrifugal compressors compared to reciprocating compressors (A) Require less space (B) Have quieter operation (C) Have lower operating costs (D) All (A), (B) and (C)

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

Explain about the air compressor modulation by optimal pressure settings.

Description : Explain about the air compressor modulation by optimal pressure settings. 

Last Answer : Very often in an industry, different types, capacities and makes of compressors are connected to a common distribution network. In such situations, proper selection of a right combination of compressors and ... different pressures and energy efficient ones must be made to meet most of the demand. 

What are the different types of pressure regulators available for air compressor system?

Description : What are the different types of pressure regulators available for air compressor system? 

Last Answer : Pilot operated type Direct acting type Self – relieving type 

Briefly describe about ‘rotary compressor’?

Description : Briefly describe about ‘rotary compressor’?  

Last Answer : Rotary compressors have rotors in place of pistons and give a continuous, pulsation free discharge. They operate at high speed and generally provide higher throughput than reciprocating compressors. They are directly ... , vibrate less, and have a lower number of parts which are subject to wear. 

If the compressor of 200 cfm loads in 10 seconds and unloads in 20 seconds, the air leakage would be_____ a) 67 cfm b) 100 cfm c) 10 cfm d) 133 cfm

Description : If the compressor of 200 cfm loads in 10 seconds and unloads in 20 seconds, the air leakage would be_____ a) 67 cfm b) 100 cfm c) 10 cfm d) 133 cfm 

Last Answer : a) 67 cfm

Which of the following parameters are not required for evaluating volumetric efficiency of the compressor? a) Power b) Cylinder bore diameter c) Stroke length d) FAD

Description : Which of the following parameters are not required for evaluating volumetric efficiency of the compressor? a) Power b) Cylinder bore diameter c) Stroke length d) FAD

Last Answer : a) Power

The basic function of air dryer in a compressor is: a. prevent dust from entering compressor b. storage and smoothening pulsating air output c. reduce the temperature of the air before it enters the next state to increase efficiency d. to remove remaining traces of moisture after after-cooler

Description : The basic function of air dryer in a compressor is: a. prevent dust from entering compressor b. storage and smoothening pulsating air output c. reduce the temperature of the air before it enters the next state to increase efficiency d. to remove remaining traces of moisture after after-cooler 

Last Answer : d. to remove remaining traces of moisture after after-cooler 

The ratio of isothermal power to actual measured input power of a compressor is known as: a) Isothermal efficiency b) Volumetric Efficiency c) Barometric efficiency d) None

Description : The ratio of isothermal power to actual measured input power of a compressor is known as: a) Isothermal efficiency b) Volumetric Efficiency c) Barometric efficiency d) None 

Last Answer : a) Isothermal efficiency

The volumetric efficiency of the compressor ______ with the increase in altitude of place a) increases b) decreases c) does not change d) None

Description : The volumetric efficiency of the compressor ______ with the increase in altitude of place a) increases b) decreases c) does not change d) None

Last Answer : b) decreases

What Is The Difference Between A Rotary Screw Compressor And A Reciprocating Compressors?

Description : What Is The Difference Between A Rotary Screw Compressor And A Reciprocating Compressors?

Last Answer : A rotary screw compressor is one that utilizes two intermeshing helical rotors to trap a volume of air, then compress it to a higher pressure. Rotary screw compressors can be run at lower ... piston compressor (aka reciprocating) uses pistons driven by a crankshaft to deliver air at high pressure.

The specific speed of a centrifugal compressor is generally A. less than that of reciprocating compressor B. independent of compressor type, but depends only on size of compressor C. higher than that of axial compressor D. more than specific speed of reciprocating compressor but less than axial compressor

Description : The specific speed of a centrifugal compressor is generally A. less than that of reciprocating compressor B. independent of compressor type, but depends only on size of compressor C. higher ... axial compressor D. more than specific speed of reciprocating compressor but less than axial compressor

Last Answer : ANSWER : C

Which one of the following statements is correct? A. Reciprocating compressors are used to supply large quantities of air at a lower pressure ratio B. Centrifugal compressors are used to supply large quantities of air at a lower pressure ratio C. Centrifugal compressors are used to supply small quantities of air at a lower pressure ratio D. Centrifugal compressors cannot be run at high speed because of impeller, diffuser and casing.

Description : Which one of the following statements is correct? A. Reciprocating compressors are used to supply large quantities of air at a lower pressure ratio B. Centrifugal compressors are used to supply ... . Centrifugal compressors cannot be run at high speed because of impeller, diffuser and casing.

Last Answer : ANSWER : B

Explain construction and working of two stage reciprocating air compressors.

Description : Explain construction and working of two stage reciprocating air compressors.

Last Answer : Figure: Two Stage Reciprocating air compressor Construction and Working : It consists of two cylinders (L.P. and H.P.) with water cooled intercooler and air receiver. First of all fresh air is ... (ie second stage) from 3 to 4 is delivered by the compressor at pressure P3 & Temp T4.

In a single stage reciprocating air compressor, the work done on air to compressor is from suction pressure to delivery pressure will be minimum when the compression is A. Isothermal process B. Adiabatic process C. Polytropic process D. Constant pressure process.

Description : In a single stage reciprocating air compressor, the work done on air to compressor is from suction pressure to delivery pressure will be minimum when the compression is A. Isothermal process B. Adiabatic process C. Polytropic process D. Constant pressure process.

Last Answer : ANSWER : A

Which of the following is used for pumping crude oil from oil well? (A) Single stage centrifugal pump (B) Gear pump (C) Screw pump (D) Duplex/triplex reciprocating pump

Description : Which of the following is used for pumping crude oil from oil well? (A) Single stage centrifugal pump (B) Gear pump (C) Screw pump (D) Duplex/triplex reciprocating pump

Last Answer : (D) Duplex/triplex reciprocating pump

Reciprocating pumps (A) Are not suitable for variable heads (B) Are four times costlier than centrifugal pumps (C) Are not suitable for pumping water containing sediments (D) Single stroke produce pulsating flow

Description : Reciprocating pumps  (A) Are not suitable for variable heads  (B) Are four times costlier than centrifugal pumps  (C) Are not suitable for pumping water containing sediments  (D) Single stroke produce pulsating flow 

Last Answer : (A) Are not suitable for variable heads 

The domestic refrigerator uses following type of compressor (a) centrifugal (b) axial (c) miniature sealed unit (d) piston type reciprocating

Description : The domestic refrigerator uses following type of compressor (a) centrifugal (b) axial (c) miniature sealed unit (d) piston type reciprocating

Last Answer : Ans: d

Which of the following can be used to create a flow of gas, where no significant compression is required? (A) Reciprocating compressor (B) Blower (C) Axial flow compressor (D) Centrifugal compressor

Description : Which of the following can be used to create a flow of gas, where no significant compression is required? (A) Reciprocating compressor (B) Blower (C) Axial flow compressor (D) Centrifugal compressor

Last Answer : (B) Blower

Differentiate between : (i) Reciprocating and rotary air compressor (ii) Centrifugal and axial flow compressor

Description : Differentiate between : (i) Reciprocating and rotary air compressor (ii) Centrifugal and axial flow compressor

Last Answer : (i) Reciprocating and rotary air compressor: Sr. No. Reciprocating air compressor  Rotary air compressor  1 It is having to and fro motion. It is having rotary ... I.C. engine and for refrigerants and industrial gases. Used universally with large gas turbine. 

The acceptable pressure drop at the farthest point in mains header of an industrial compressed air network is: a)0.3 bar b) 0.5 bar c) 1.0 bar d) 2 bar

Description : The acceptable pressure drop at the farthest point in mains header of an industrial compressed air network is: a)0.3 bar b) 0.5 bar c) 1.0 bar d) 2 bar

Last Answer : a)0.3 bar

Difference between Single stage compressor and Multi stage compressor.

Description : Difference between Single stage compressor and Multi stage compressor.

Last Answer : Single stage compressor Multi stage compressor. Only one cylinder for the compressor process More than one cylinder is connected in series Used in low pressure application Achieve a very ... low Suitable for light task Suitable for heavy task. It can manage large load

Air Conditioning/ Electrical

Description : The coil of a transformer that is energized from a source of alternating voltage is known as the: A. low voltage winding B. high voltage winding C. primary winding D. secondary winding

Last Answer : C

Electricity or Air Conditioning

Description : There is a single-phase motor connected in parallel with an electric heater unit. If the heater is switched off, then the overall power factor angle of the circuit will: A. increase B. decrease C. stay the same D. none of the above

Last Answer : A

Explain the simple steps that can be followed in shop – floor for quantification of compressed air leakages.

Description : Explain the simple steps that can be followed in shop – floor for quantification of compressed air leakages.  

Last Answer : The following steps can be followed for quantification of compressed air leakages. Shut off compressed air operated equipments (or conduct test when no equipment is using compressed air). Run the compressor to ... per minute (cmm) T = Time on load in minutes T = Time unload in minutes 

What are the most common types of compressed air dryers used?

Description : What are the most common types of compressed air dryers used? 

Last Answer : a. Heat – less dryer (absorption) b. Adsorption dryer c. Chiller dryer (refrigerated dryers)

List the components of a compressed air system.

Description : List the components of a compressed air system. 

Last Answer : The various components of a compressed air system are: • Intake air filters • Inter-stage coolers • After coolers • Air-dryers • Moisture traps • Receivers 

Explain about the importance of optimal Pressure settings of a compressed air network

Description : Explain about the importance of optimal Pressure settings of a compressed air network 

Last Answer : The power consumed by a compressor depends on its operating pressure and rated capacity. They should not be operated above their optimum operating pressure as this not only wastes energy, but also leads ... switches must be adjusted such that the compressor cut-in and cuts-off at optimum levels. 

What is the function of an air receiver?

Description : What is the function of an air receiver?

Last Answer : The main purpose of a receiver is to act as a pulsation damper, allowing intermittent high demands for compressed air to be met from a small compressor set, resulting in lesser energy consumption.