How do you calculate the efficiency of pumps???

 

How do you calculate the efficiency of a pump?

Efficiency of the pump is the ratio of output power to the input power

Pump efficiency = Output power X 100 / Input power

Centrifugal pumps efficiency varies from 40% to 95% well.

Pump efficiency is equal to the power of the water/liquid produced by the pump divided by the pump’s shaft power input.

A pump’s output power is determined by how much water and how much pressure it delivers 

On what factors pumps efficiency depends on?

Pumps efficiency depends on

• In put power
• Output power
• Type of liquid
• Fluid temperature
• Flow
• Suction & discharge head
• Losses & leakages
• Fluid viscosity
• Pump operating load
• Pumps internal frictions

What do you mean by volumetric efficiency of a pump?

It is the ratio of actual flow delivered by the pump to the theoretical flow

How do you calculate the Mechanical or hydraulic efficiency of the pump?

Mechanical/Hyd.efficiency = Pump output power X 100 / Pump input power or pump shaft power

Mechanical efficiency is also calculated as

 = Theoretical torque required to drive the pump X 100 / Actual torque provided to drive the pump

Meachanical Seals

Calculations:

A centrifugal pump delivers 0.2 m3/sec flow at total head 27 m, calculate its hydraulic power. Assume density of water 995 kg/m3

Pump hydraulic power = Pump flow in m3/sec X pump total head in meter X Fluid density in kg/m3 X 9.81 m/sec2 / 1000

Pump hydraulic power = 0.2 X 27 X 995 X 9.81 / 1000

Pump hydraulic power = 52.7 KW

A centrifugal pump of capacity 0.05 m3/sec flow has to lift the water from 3.5 m deep well & has to discharge the water at 45 meter height. Calculate the pump efficiency if its shaft power is 30 KW

Assume water density 998 kg/m3

Pump hydraulic power = Pump flow in m3/sec X pump total head in meter X Fluid density in kg/m3 X 9.81 m/sec2 / 1000

Total head = Discharge head + Suction lift

Total head H = 45 + 3.5 = 48.5 meter

Pump hydraulic power = 0.05 X 48.5 X 998 X 9.81 / 1000

Ph = 23.74 KW

Pump efficiency =Pump hydraulic power X 100 / Pump shaft power

Pump efficiency =23.74 X 100 / 30

Pump efficiency =79.13%

A centrifugal pump of delivering  0.65 m3/sec flow at 75 meter discharge head, pump has positive suction head around 2.7 meter from overhead tank.Pump efficiency is 59%, calculate the motor input power if efficiency power if efficiency of motor is 92.5%.

Assume water density 1000 kg/m3

Pump hydraulic power = Pump flow in m3/sec X pump total head in meter X Fluid density in kg/m3 X 9.81 m/sec2 / 1000

Total head = Discharge head -Suction head

Total head H = 75 -2.7 = 72.3 meter

Pump hydraulic power = 0.65 X 72.3 X 1000 X 9.81 / 1000

Ph = 461 KW

Pump efficiency =Pump hydraulic power X 100 / Pump shaft power = Ph X 100 / Ps

59 =461 X 100 / Ps

Ps = 781.35 KW

Motor efficiency = Pump shaft power X 100 / Motor input power =Ps X 100 / Pm

92.5 = 781.35 X 100 / Pm

Pm = 844.7 KW

A centrifugal pump of efficiency 63% develops hydraulic power 27.5 KW, calculate the motor efficiency if motor input power is 45 KW

Pump shaft power, Ps = Pump hydraulic power Ph / Efficiency of pump

Ps = 27.5 / 0.63 =43.65 KW

Motor efficiency = Pump shaft power X 100 / Motor input power

Motor efficiency= 43.65 X 100 / 45

Motor efficiency = 97%

8mm Graphite Gland Packing Rope 8 MM Color. Black 10meter 2kg

 

 

Buy Money plant to create positive energy at your loved home

For more articles on power plant Read

Powerplant and calculations

 

Practical Approach to Power Plant Operation and Maintenance

 

Top Industrial Tools and Tackles Used in Thermal PowerPlants

 

How to calculate ESP efficiency??

 

On what factors ESP efficiency depends on?

ESP efficiency depends on following factors.

• Dust collection area of ESP
• Dust particles size
• Dust or flue gas volume
• Resistivity of dust particles present in flue gas

What do you mean by Corona Power ratio?

Corona power ratio is the ratio of power consumed in watts to the flue gas flow in cubic feet per minute.

Corona power ratio = Power consumed by ESP in watts / Flue gas flow in CFM

This tells us about the energy consumed in filtering one cubic foot of flue gas per minute. The corona power ratio affects the efficiency of an electrostatic precipitator. Higher the corona power ratio, higher is the efficiency of the electrostatic precipitator

Mini Digital Anemometer Air Wind Speed with Temperature Measurement (With Calibration Certificate)

What do you mean by specific collecting area (SCA) & how do you calculate it?

It is the ratio of total collecting surface area of the ESP to the flue gas flow rate

SCA = Total collection area in m2 / Gas flow rate in m3/sec

SCA = m2/m3/sec

What do you mean by Aspect ratio in ESP?

It is the ratio of length of ESP to its Height

It should be in the range of 0.5 to 2

Calculation:

Calculate the aspect ratio of an ESP of total length 12 meter having its collecting plates height 11 meter.

Aspect ratio (AR) = Length of ESP / Height of ESP

Aspect ratio (AR) = 12/11 =1.09.

What is the treatment time in ESP having flue gas flow rate 90 m3/sec at velocity 0.7 m/sec.ESP having total 4 nos of fields each of length 3.5 meter.

We have, total length of ESP = 3.5 X 4 = 14 meter

Velocity of flue gas in ESP = 0.7 m/sec

So, total Treatment time for flue gas = 14 / 0.7 =20 seconds

Read power plant O&M reference books

An ESP consumes 7 KW power for treating flue gas of 17 m3/sec, calculate its Corona power ratio.

Corona power ratio = Power consumed by ESP in watts / Flue gas flow in CFM

We have flue gas flow = 17 m3/sec = 599.9 X 60= 35994 CFM

CPR = 7000 / 35994 = 0.2

An ESP handles total flue gas at the rate of 61920 m3 /h., its specific collecting surface area is 131.9 m2/m3/sec, calculate the efficiency of ESP if ash particles migration velocity is 5.46 cm/sec.

Read more>>>>

Boiler Explosion and Control Measures: A Complete Guide

 Solution:

Given that,

Flue gas flow in ESP, Q = 61920 m3/hr / 3600 = 17.2 m3/sec

Total collecting area A= 131.9 X 17.2 =2268.68 m2

Migration velocity of dust particles, V = 5.46/100 = 0.0546 m/sec

Efficiency of ESP = 1–eˆ (-AV/Q) X 100

                            = 1– eˆ (-2268.68 X 0.0546/17.2) X 100

                   ηESP = 99.92%

 Read more>>> for such calculations powerplant & Calculations

Also read ESP troubleshooting guide

How do you calculate the efficiency of Economiser in Boiler??

 

What is the Economiser in power plants?

It’s the heat exchanger used in Boilers to recover the heat from exhaust flue gases.

What are the functions of economisers in Boilers?

Functions of economisers:

It recovers the heat from flue gas leaving the boiler, there by reduces the losses

It helps in raising the feed water temperature, there by reduces the fuel consumption

It increases the Boiler efficiency

It lowers the power plant operation cost

What are the different types of economisers?

Types of economisers

Pressurized economisers

Non pressurized economisers

Steaming type

Non steaming pipe

What do you mean by steaming type economisers?

Economisers where only sensible heat is added to feed water

What do you mean by non-steaming type economisers?

Economisers where sensible heat and part of latent is added to feed water

Efficiency Calculations:

ηEco. = (Economiser outlet feed water temperature Two-Economiser inlet feed water temperature Twi)  X 100 / (Economiser inlet flue gas temperature Tfi- Economiser inlet feed water temperature Twi)

 Read APH efficiency calculation

Example:

Calculate the economiser effectiveness, whose feed water inlet & outlet temperatures are 160 Deg C & 240 Deg C respectively & flue gas inlet & outlet temperatures 390 deg C & 220 deg c respectively.

 

Solution:

 

Twi = 160 deg C

Two = 240 deg C

Tfi = 390 deg C

Tfo = 220 deg C

ηEco = (Two-Twi) X 100 / (Tfi-Twi)

ηEco = (240-160 ) X 100 / (390-160)

ηEco= 34%

 

In an non steaming economiser of efficiency 51%, feed water inlet and outlet temperatures are 105 deg c & 160 deg C respectively, calculate the flue gas temperature entering the economiser

Solution:

 

Twi = 105 deg C

Two = 160 deg C

Tfi = 370 deg C

Tfo = ? deg C

ηEco= 51%

 

ηEco = (Two-Twi) X 100 / (Tfi-Twi)

51= (160-105 ) X 100 / (Tfi-105)

Tfi X 51-105 X51 = 5500

Tfi = 212.8 deg C

 

A economiser inlet feed water & flue gas temperature are 125 deg C and 405 deg C respectively, calculate the feed water leaving the economiser, consider efficiency of economiser 43%

Solution:

 

Twi = 125 deg C

Two = ? deg C

Tfi = 405 deg C

ηEco= 43%

 

ηEco = (Two-Twi) X 100 / (Tfi-Twi)

43= (Two-125 ) X 100 / (405-125)

12040 = 100 X Two-12500

Two = 245.4 deg C

 

For more calculations related to power plant read 

Powerplant & Calculations

Read more on>>>>Boiler and Turbine Hub

List of top measuring instruments used in Power plants

How do you calculate the efficiency of Air pre heater (APH) in Boilers??

 

APH is an auxiliary used in steam generators or boilers to increase the Boiler efficiency and to reduce the fuel consumption.

There are different types of air heaters. Major types are tubular & regenerative air preheater.

These may be installed horizontally or vertically as per requirement.

In some design of APH air flows outside the tubes and flue gas inside the tubes where as in some cases air flows inside the tubes and flue gas outside of the tubes.

The main functions of APH is to reduce the flue gas temperature to allowable limit that is coming out from Boiler and to increase combustion air temperature.

The efficiency of the APH are calculated from two ways one is from air side other from gas side.

APH gas side efficiency

ηAPHg = (Flue gas inlet temp.Tfi-Flue gas outlet temp.Tfo) X 100 / (Flue gas inlet temperature tfi-Air inlet temperature Tai)

 Read>>>>Why do high pressure Boilers have higher efficiency??

APH air side efficiency

ηAPHa = (Air outlet temp.Tao-Air inlet temp.Tao)) X 100 / (Flue gas inlet temperature tfi-Air inlet temperature Tai)

 Read power plant O&M reference books

Calculate the APH gas side & air efficiency if its flue gas inlet and out let temperature are 230 deg C and 145 deg C and air inlet and out let temperatures are 28 deg C & 180 deg C respectively.

ηAPHg = (Flue gas inlet temp.Tfi-Flue gas outlet temp.Tfo) X 100 / (Flue gas inlet temperature tfi-Air inlet temperature Tai)

 

ηAPHg =(230-145) X 100 / (230-28)

ηAPHg = 42.1%

ηAPHa = (Air outlet temp.Tao-Air inlet temp.Tao)) X 100 / (Flue gas inlet temperature tfi-Air inlet temperature Tai)

 

ηAPHa = (180-28) X 100 / (230-28)

ηAPHa = 75.24%

Read Economiser efficiency calculation

A Tubular type APH is having air side efficiency 79%, its flue gas and air inlet temperature are 225 deg and 30 deg C respectively, calculate the APH outlet air temperature

Mini Digital Anemometer Air Wind Speed with Temperature Measurement (With Calibration Certificate)

We have,

ηAPHa = (Air outlet temp.Tao-Air inlet temp.Tao)) X 100 / (Flue gas inlet temperature tfi-Air inlet temperature Tai)

 

79% = (Tao-30) X 100 / (225 – 30)

Tao-30 = 0.79 X 195

Tao = 184.05 deg C

A Tubular type APH is having gas side efficiency 39%, its flue gas and air inlet temperature are 225 deg and 30 deg C respectively, calculate the APH outlet flue gas temperature

We have,

ηAPHg = (Flue gas inlet temp.Tfi-Flue gas outlet temp.Tfo) X 100 / (Flue gas inlet temperature tfi-Air inlet temperature Tai)

 

39% = (225-Tfo) X 100 / (225-30)

0.39 X 195 = 225-Tfo

Tfo = 148.95 deg C

Read power plant and calculations

Boiler and Turbine Hub

Reasons for Priming, Foaming and carryover in Boilers

 

Priming:

1. What do you mean by the term Priming?

Priming means carryover of water particle in the steam

2. What are the reasons for Priming?

Reasons for priming;

• Improper design of Boiler and steam drum
• Maintaining high drum level
• Boiler load fluctuation
• Sudden load raise due to steam demand
• Foaming in feed water
• Miss operation of Boiler
• Sudden lifting of Boiler safety valve or start up vent CV
• More impurities in Boiler water

3. What are the impacts of Priming?

Impacts of Priming;

• Lower steam efficiency
• Water hammering
• Super heater coil failure due to thermal shock
• Turbine high vibration & blade failure

How do you avoid priming in Boilers?

Priming can be avoided by;

• Proper operation of boiler
• Maintaining drum level in between 45 to 55%
• Avoiding foaming
• Avoiding sudden load fluctuation
• Proper designing of Boiler

Professional Laboratory pH/mV Meter (Model BNPH002) | 0.01 pH Resolution, ±0.05% Accuracy

Carryover:

What do you mean by the term carryover?

Carryover is the carryover of solid, liquid & gaseous contaminants with water and steam leaving the drum due to incomplete separation of water and steam in steam drum.

What are the major reasons for carryover?

Reasons for carryover;

• Defects in steam and water separators
• Foaming
• Boiler load fluctuation
• Higher drum level
• Boiler steam drum construction defects

What are the effects of carryover on Boiler components?

Contamination in steam leads to deposition of solid scale on Super heater coils & control and regulating valves.

Foaming:

What do you mean by the term foaming?

Foaming is the formation of unbroken bubbles on the surface of the boiler water inside the boiler drum.

The bubbles may be in thin layer with few bubbles overlying each other or it may build up throughout the steam space.

TDS meter and PH Meter combo, tds and ph testers for water testing

What are the reasons for foaming?

•  High suspended solid concentration
•  High alkalinity concentration
•  High dissolved solid concentrations in the boiler water
•  Oil and organic contaminants in the boiler water
• High impurities
• High dosage of chemicals
• High water level

How do you avoid foaming?

• Timely blow down & maintaining desired water quality
• Maintaining constant load on Boiler
• Avoiding high water level

For more articles read Boiler and Turbine Hub

Read Power plant O&M guide books

Combustion air in Boilers and related calculations

1. What do you mean by combustion air?

The amount of air required for complete combustion of fuel in furnace is called as combustion air. The efficiency of the Boiler or furnace depends on efficiency of combustion system.

2. On what parameters the requirement of combustion air depends?

Combustion air requirement depends on;

• Type of fuel burnt
• Type & quantity of its elemental constituents
• Type of Boiler and furnace
• Amount of moisture content in it

3. What is the relation between moisture content in the fuel & combustion air required?

Combustion air requirement increases as the moisture content in the fuel increases and vice versa

4. What is the relation between carbon & Hydrogen content in the fuel & combustion air required?

Combustion air requirement increases as the % of carbon & Hydrogen content in the fuel increase and vice versa.

5. What is the relation between oxygen content in the fuel & combustion air required?

Combustion air requirement decreases as the % of oxygen content in the fuel increases and vice versa.

6. Do content of sulphur & Nitrogen in the fuel affect combustion air requirement?

Increase and decrease in sulphur & Nitrogen content in the fuel does not affect much on combustion air requirement.

7. What is meant by total air of combustion?

Thermal Master Industrial Thermal Imaging Camera | 256x192 IR Resolution | 3.5” Display | -20°C to 550°C | ±1.5% Accuracy

The total air supplied to the Boiler combustion chamber is divided into two parts Primary air and secondary air.

Primary air supports the flame and takes part in the initial combustion process. The second part is called as secondary air. Secondary air is admitted into the furnace from top to create turbulence in furnace and to ensure complete combustion of the fuel.

8. What are the functions of Primary and secondary air in Travelling grate, pulverized coal fired and FBC Boilers?

In case of travelling grate Boilers Primary air is supplied below the grate to support flame & combustion stabilisation. And secondary air from top of the furnace as over fired air to create turbulence for complete combustion. And also secondary air is used to spread the fuel in furnace

In case of Pulverized coal fired Boilers, Primary air is used to carry the pulverized coal into the furnace.

In case of FBC Boilers Primary air is used to carry fuel and fluidisation. Secondary air is supplied above the bed to ensure complete combustion

9-What is meant by theoretical air & excess air in combustion?

Read more>>>>>>Boiler and Turbine Hub

Theoretical air: Amount of air required to burn the fuel. It is stoichiometric air, it does not ensure complete combustion.

Excess air: Amount of extra air given for complete combustion

10-Calculate the Theoretical air required to burn imported coal having carbon 55%, Oxygen 8.2%, Hydrogen 3.3% and sulphur 0.32% in it

Theoretical air is calculated by using below formula

Thair = (11.6 X %C + 34.8 X (%H2-%O2/8) + 4.35 X %S)) / 100

Thair = (11.6 X 55 + 34.8 X (3.3-8.2/8) + 4.35 X 0.32)) / 100

Thair = 7.18 kg/kg of fuel burnt

In the above formula, you can vary the % of Carbon, Hydrogen & Sulphur to observe changes in air requirement

11-How do you measure % of excess air supplied?

Excess air is generally measured from Oxygen analyser installed at the out let of Boiler (Economiser)

It is to be noted that, excess air & excess oxygen are not same. Air has around 21% of oxygen in it by volume. So, 100% excess air is roughly equals to 10.5% of oxygen.

12-What is the significance of excess air?

For combustion, if less air is supplied it leads to incomplete combustion forming CO instead of Co2. And if more excess air is supplied it leads to reduction of combustion efficiency by cooling the furnace & carrying the heat through flue gas.

So, it is important to adjust the air supply in such a way that complete combustion will take place without much extra air.

13-Calculate the % of excess air required if oxygen measured in flue gas at economiser outlet is 5.5%.

Excess air = O2% X 100 / (21-O2%)

Eair = 5.5 X 100 / (21-5.5)

Eair = 35.48%

14-Calculate the total air required for complete combustion of coal if Theoretical air supplied is 7.1 kg/kg of coal and O2 measured in flue gas is 6.4%

Actual or total mass of air supplied = (1 + Excess air / 100) X theoretical air

We have

Excess air = O2% X 100 / (21-O2%)

Eair = 6.4 X 100 / (21-6.4)

Eair = 43.84%

Actual or total mass of air supplied = (1 + 43.84 / 100) X 7.1

Actual or total mass of air supplied = 10.21 kg/kg of coal

15-How do you control the excess air?

Excess air is controlled by;

• Optimizing the moisture content in the fuel
• Improving combustion chamber performance
• Auto control of fuel feeding
• Continuously monitoring O2 content in flue gas
• Incorporating auto combustion control
• Incorporating VFD drives to ID, FD, PA & SA fans

Non-Contact Infrared Digital Temperature Gun, Resolution Infrared Thermometer, Multi-Purpose, Wide Range

16-Among Bagasse, coal and Natural gas, which fuel needs more excess air?

Bagasse, since it has more moisture content

17-A boiler has supplied 27% excess air, calculate % of O2 in flue gas

Excess air = O2% X 100 / (21-O2%)

27 = O2% X 100 / (21-O2%)

27 X 21 -27 X %O2 = 100 X O2%

567= 127 O2%

O2% = 4.46

Read Powerplant & calculations

Reasons for priming, foaming and carryover in Boilers

Top reference books for Boiler operators and engineer exams

How do you carryout performance Guarantee (PG) test of power plant equipments??

 

What do you mean by performance Guarantee (PG) test?

 It is a test carried out to measure the performance of an equipment as guaranteed by the manufacturer.

What are the equipments on which PG test is carried out in power plants?

Generally all the equipments should met manufacturer guarantee performance value, but in Power plant, Boiler, Turbine & Generators are the major & critical equipments where PG tests are carried out.

When & who do carryout PG test?

PG test is carried out after erection & commissioning of the equipments and before hand over of the equipments PG test is carriedout.PG test is carried out. It is carried out by Original Equipment Manufacturer (OEM).

Best reference books for Turbine operation and maintenance

How do you carryout PG test?

For conducting the PG test, some parameters are measured & compared with standard design & operating values. Before conducting PG test, it is mutually agreed between OEM & Owner what parameters to be measured & means of measurement. And also it is mutually agreed that, how much time this test will be conducted. In some cases PG test is conducted for 8 hours, in some cases 24 hours.

And also the frequency of parameters measurement is decided before commence of PG test.

Procedure for PG test.

Testing Methodology: Standard testing methodology is decided

Testing equipment: Type of equipment, its measuring accuracy & calibration reports

Tolerance: The margin of error.

Ambient temperature: It is most important for conducting PG test since all the equipments & systems are designed on the basis of atmospheric temperature.

Parameters Log sheet & List of Operation team to be involved in PG tests are decided before the test.

Once the PG test completes, log sheets are collected & should be signed by owner & OEM for future reference.

Click here for >>>>>Boiler and Turbine hub 

What is the significance of carrying out PG test in Boilers?

PG test is carried out to ensure following key performance Indicators (KPIs) of Boiler

• Specific fuel consumption of the Boiler or steam to fuel ratio (SFR)
• Steam Purity
• Steam pressure & temperature at various operating condition
• Boiler efficiency
• Load stability during various load demand
• Stack gas quality
• Minimum & maximum rating

What parameters are measured during Boiler PG test?

• Steam pressure & temperature
• Steam flow & feed water flow
• Fuel consumption
• Attemperator/Desuper heater water flow
• Feed water parameters like pH, conductivity, silica, Hydrazine
• Boiler Water parameters like pH, conductivity, silica, Phosphate
• Steam parameters like pH, conductivity, silica etc
• Feed water temperature at Deaerator outlet
• Feed water temperature at Economiser inlet
• Exhaust flue gas temperature
• Excess air & O2% in flue gas
• Flue gas parameters like SPM, SOx, NOx etc
• ESP & APH inlet & outlet flue gas temperature for air leakage test
• Combustion air temperature after APH
• Unburnt level in ash
• CBD water flow
• Drum level
• Boiler auxiliary power consumption
• Operating % of load Fans& fuel feeding system at various Boiler load.

In this test, a boiler is allowed to generate steam at various load conditions. Its capability to generate steam at required parameters and required efficiency is checked.

Note: While conducting Boiler PG test, input parameters like fuel moisture, GCV etc kept as per design values

What is the significance of carrying out PG test in Turbines?

PG test is carried out to ensure following key performance Indicators (KPIs) of Boiler

• Specific steam consumption (SSC)
• Exhaust steam temperature
• Condenser vacuum
• Heat rate & efficiency
• Turbine bearing vibrations & temperature
• HP valve demand during various load demand
• Turbine Noise level
• Stability during sudden load cut off
• Steam pressure & temperature of extraction & bleed steam
• Turbine auxiliary power consumption

What parameters are measured to conduct PG test of steam Turbine?

• Turbine inlet steam pressure & temperature
• Turbine inlet steam flow
• Auxiliary steam flow
• Condenser inlet & outlet cooling water temperature
• Turbine & Gear box all bearings & vibrations
• Noise level around turbine
• Load on Generator
• Oil cooler inlet & outlet water & oil temperature
• HP & LP valve lift & demand
• Turbine casing thermal expansion
• Wheel chamber pressure
• Pressure, temperature & steam flow of extraction & bleed steam
• Exhaust steam pressure, temperature and flow

What parameters are checked for PG test of Generators?

• Generator output power
• Terminal voltage
• Frequency
• Current
• Power factor
• Winding & air temperature
• Air cooler inlet & outlet water temperature

 

 Read.

Power plant equipments SOP

Power plant & calculations.

 

 

List of top measuring instruments used in Power plants