energy management srkr

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T.CHANDRA KIRAN,Y4EE051,

B.Tech, EEE,V.R.SIDDHARTHA ENGINEERING COLLEGE,

VIJAYAWADA.

MAIL ID:[email protected]:9885287503

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ABSTRACT:

ENERGY MANAGEMENTprogram is an effective tool in evaluating energy saving

measures. The sole purpose of energy management is to conserve the energy. Energy management and

energy conservation are two sides of a same coin. In this paper thermal power plants in India are taken

in to consideration. In order to meet the power generation requirement ENERGY MANAGEMENT

is the best method to re-power the old power plants in India. The need for the energy management is

stressed and the steps involved in the energy management program are discussed. Many energy saving

methods are proposed and the justified selection of different methods are discussed.

Finally with the kind help of VIAYAWADA THERMAL POWER

STATION (VTPS)officials, a case study on Energy management in VTPS is included.

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Introduction:

Energy requirement goes on increasing day by day in the present world. The price of fuel

(coal, oil) goes on increasing thereby increasing the cost of generation of electricity

In India the present installing capacity is 1,24,287 MW (April 2006) which include 70% of

power is generated from Thermal power plants in India, 25%from Hydel plants, 2.5% from Nuclear,

1.74% from wind power , 0.1% from solar plants, 0.2%from from biomass and baggage and 0.5% is

generated from other sources. But the requirement will increase to 2,00,000 MW by 2012. In order to

bridge the gap, establishment of new plants is not practical due to

High cost of installation

Gestation period is large

Limited availability of new site

Therefore we should look for some other alternatives. Consider thermal power plants

which accounts for 70% of power generation in India, the challenges before thermal power plants are

India has largest number of old plants which are inefficient and running below designed

capacity

Operation pressure and temperature of these plants are lower than designed

Some equipment have degraded

Deteriorating of quality coal.

In this present scenario Energy Management is the best energy security. Energy

management program is an essential tool in evaluating the energy saving measures.

In power generation industry we usually have a situation where we have to make a

choice between equipment of high cost with high efficiency and low cost with low efficiency. The

management has to balance the situation in such a way that the annual expenditure is minimal.

Need:

Energy management helps business against increasing oil and coal prices. Energy management

provides systems and solutions with return on investment with in certain period. Wear and tear of

equipment increase as the age of the plant increases. On a process energy saving techniques,

replacements and future expansions are very important aspects to be carefully studied in order to

improve the efficiency of the plant thereby reducing the power generation cost. Energy management

program has a wide range of energy saving ability from generation side to consumer side.

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1%increase in the efficiency of the plant results in 3% reduction in coal consumption and 3%

reduction of emission ofSOx, NOx, corbon-di-oxide in to the atmosphere. Energy management helps to

maximize energy saving, reduces waste and improve productivity. It permits the manufacturer to be

more competitive and profitable.

Advantages:

Small investment is required.

Low gestation period

Reduces cash outflow thus industry is more competitive

Addition to profits without big investments

Increase productivity

Environmental benefits

Process:

An organized group known as Energy Conservation Committee (ECC) should be formed at

each power plant to establish and implement the overall energy program. The size and composition of

this group may vary, but representatives from each of the significant energy consuming areas, the

energy producing areas, and the engineering maintenance group should also be represented. The

responsibilities of ECC should include.

Determining the scope of the plants energy conservation program.

Establishing a schedule and monitoring the results for the overall energy conservation program.

Recommending changes and modifications to reduce energy requirement.

Training or encouraging the employees and workers to conserve energy.

Any successful energy management program must have the co-operation and support of the

entire line of organization. Team work will always provide best results. One simple but effective

measure of program is Quality control technique. It involves weekly, biweekly or monthly checks of

all operating areas to determine the number of energy violations that exist at that particular time.

This method of waste control can reduce energy violations dramatically with in two or three months.

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Steps:

After formation of ECC following steps should be taken in energy management program

Step 1: MEASURE: Identifying all opportunities to conserve energy.

Step 2: DETECT: Prioritizing and evaluating major energy saving equipments.Step 3:CONTROL: Taking cost saving measures.

Step 4: MONITOR: Maintain and monitoring the activities.

Step 1: MEASURE

Before taking any action, first all the opportunities to conserve energy should be determined.

It is very important to find all the opportunities possible to determine the best energy saving method. It

the responsibility of an energy management program to avoid spending the money of the plant unless

we are not certain where it can be spend more effectively. This formal process usually called asEnergy Audit is needed to find all opportunities possible.

Energy audit deals with specific ways and means to achieve energy conservation. Energy

audit is the key to a systematic approach for decision-making in the area of energy management.

Energy audit will help to understand more about the ways energy and fuel are used in power plant and

help in identifying the areas where waste can occur and where scope for improvement exists.

Scope of Energy Audit:

Analyzing present consumption and past trends in detail.

Check for air and flame leakage through the brick work of the furnace, its doors, roof etc.

Check for oil leakage near burners.

Is there water treatment plant in use and quality of feed water monitored.

Checking capacities and efficiencies of all equipments in the plant.

Considering sub metering.

Comparing standard consumption to actual.

Examining and monitoring new energy saving techniques.

General Audit Program:

General Audit program in power plant consists of determining energy conservation

methods in power plants.

Records of consumption:

Detailed analysis of energy consumed over the past recent years.

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Reviewing existing records of consumption and determine if adequate information is available.

Comparing standard consuming to actual for each process and identify losses.

Testing meter reading against recordings

House keeping:

Checking that all control mechanisms are effectively and frequently tested.

Checking insulation through out the plants, including tanks, roofs, walls, doors, windows, etc..

Checking that systems are properly integrated.

Checking lighting levels and maintaining proper illumination.

Considering sub metering, so that consumption can be broken down into controllable units.

Personnel:

Motivating and training staff to save energy.

Educating the staff and workers to conserve energy through posters, circulars.

Capital investment:

Reviewing efficiency of furnaces, boilers and other auxiliary equipment in plant.

Considering whether the auxiliaries are replaced or modified if required by adding metering

facilities, adding economisers.

Step 2: DETECT

After completing Energy Audit program, most energy consuming equipment is finalized and

evaluated to reduce the energy consumption.

The operation of the boiler is evaluated by considering the following:

Does boiler operate at high fire during most operational time.

Are stream lines are insulated and there are any steam leaks.

Is feed water treatment program is active.

The operation of the chillers is evaluated by considering the following:

Can cooling water be used instead of refrigerated water during any part of year.

Is chilled water produced at the highest acceptable temperature .

The operation of the air compressors is evaluated by considering the following:

Are air filters changed on regular intervals.

Are leaks present in tubes, if yes maintenance program should be carried out.

The operation of the motors is evaluated by considering the following:

Is motors are running with better power factor, if not power factor improvement steps should

be taken.

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Is lubrication of motor is periodically inspected.

The operation of the turbine &auxiliaries are evaluated as:

Determining whether the turbine is direct drive or geared drive.

Is there any leakage present in turbine generator lubricating system.

Determining whether the turbine also acts as mechanical drive other than generator.

The operation of the lightning is evaluated as:

Are lighting levels at or below those recommended for each task

Can lighting hours be reduced

Can delamping be employed

Environmental concern:

If there is no environment, there will be no man. Man is a part of environment and we should

protect it. The flue gases emitting from the plant contains harmful gases like SOx, NOx, CO2. Therefore

the ecosystem around the plant should be determined.

Effect of aquatic life, animal &bird life is observed.

Green cover around plant.

Step 3: CONTROL

After determining the most energy consuming equipments certain steps should be taken to

reduce energy conservation. It includes modification, addition or replacement of equipments.

Coal:

Implementing Clean coal technology to reduce SOx, NOx, CO2 emission. Clean Coal

Technology offers the potential for significant reduction in environmental emissions when use for

power generation. Clean coal technology refers to blending(mixing) of various grades of coal so that

the consistence in quality of coal will be maintained and ash content can be stipulate less than 34% on

annual basis.

Co- firing of biomass with coal in coal fire furnace.

Steam parameters:

Increase of steam parameters i.e., temperature and pressure is one of the most effective

measures to increase efficiency and economy well.

The most advantage is higher efficiency and ultimately saving of fuel. The improvement in

efficiency varies from 1.3 to 3.6% .Depending upon the steam parameters (600 0C, 270A) the boiler,

turbine blades and steam carrying pipes should replace or redesign.

Motors:

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Motors consume about 75% of all the power in thermal power plants. Therefore careful

maintenance and attention must be paid to motors too.

Lubrication of motors must periodically inspected.

Worn out bearings should be replaced.

Individual drive may be replaced by group drive.

If load on motor is less than 50%, then motor should be connected in star connection. The

saving will be 40 to 50%.

Motor protection like digital indication of current, hour meter etc are connected and pay back

time will be less than 12 months

The best way to reduce power is to switch off the motor when not in use.

Boiler & Auxiliaries:

Better insulation is provided to boiler to reduce wall losses.

The high efficient coal in India is exhausting. The boilers are designed taking previous coal

characteristics, therefore the boilers should be redesigned

60 MW boiler at TALCHERhas been redesigned taking present coal characteristics in to account in

order to improve the efficiency of the plant.

Retrofitting of ESPs and draft system.

Compressors:

Compressors should place near to the load so the losses will be minimum

Automatic pressure checking value should be provided to measure internal pressure and

disconnect motor.

Some other steps to conserve energy in thermal power plant are:

Turn off the equipment when not in use.

V-belts are replaced by Cog belts so that efficiency improves from 92% to 94%.

Pre-heating the boiler combustion air with waste heat

Condensation tank should be insulated

Plant roof should be insulated

Compact fluorescent lamps are most efficient compared to incandescent lamps(80% energy

saving)

Using synthetic lubricants in place of petroleum based lubricants.

Timers are required to install on lightning system

Step 4: Monitor:

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Last but not the least step is monitoring the activities in the power plant. Energy

management activity requires continuous support. There is always room for improvement. If the

progress of the plant is not up to the mark after energy management program further steps should be

taken in order to improve the performance. Program will be said to be successful when the top

managers of the plant understand that energy management program produces the profits and

efficiencies of the plant improved dramatically. Energy management program is a continuous process.

ENERGY MANAGEMENT PROGRAM NEVER ENDS.

Types of measures:

The ultimate aim of energy management program is to save economy. It is also important

to get back the money which we spend during the program for improving the efficiency of the plant.

Depending up on the time duration for recovery back of investment, measures to be taken during

energy management are classified in to

Short term measures

Medium term measures

Long term measures

Short term measures:

Meeting operational improvements require negligible capital investment.

Insulation of steam lines and equipment.

Improving fuel storage, handling and preparing practices.

By taking short term measures the potential saving of plant will improve to 5 to 10%.

The capital cost invested will get back in few months of time.

Medium term measures:

Need moderate capital cost investment, and having a pay back period of 1to 2 years.

Waste heat recovery devices and modifications and design of equipment.

Reducing wall losses in furnaces with better insulation material.

Instrumentation of furnace providing protection devices to motors and other auxiliaries.

Long term measures:

Moderanisation of inefficient drives

Replacement of boilers with modern efficient standards.

Improving the efficiencies of auxiliaries.

This type of measures require large capital and invested capital will be get back in 5 to 6

years.

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Hurdles to Energy Management:

These are some of the hurdles facing by energy management projects in Indian thermal

plants.

Shortage of capital to fund energy management projects.

Shortage of skilled staff and lack of information on techno-logical options.

Existence of limited competitive pressure to reduce cost.

Importance given towards initial cost minimization, neglecting most efficient options.

CASE STUDY:

Energy management in Vijayawada Thermal Power Plant (VTPS):

Vijayawada Thermal Power STATION(VTPS) is one of the few thermal power

stations having high plant load factor (PLF). The generation capacity of the plant is 1260 MW (210X6

units).Due to ageing of the plant, the auxiliary power consumption increases thereby reducing the overall

efficiency and increasing cost of generation.

In order to reduce the auxiliary power consumption Energy management program was

taken up. In this process, Energy Audit was carried out by Indian Power Research Institute

(IPRI),Thiruvananthapuram and submitted a 96 page report containing the energy consumed by

each auxiliary equipment and some of the ways to save energy. The process includes checking all the

energy meters and indicating instruments through out the plant for error. Determining the power factor,

load factor, voltage unbalance, current consumed by auxiliary equipment. Compare the power

consumption values of the auxiliaries with design consumptions. Recommend certain ways for an

auxiliary equipment to save energy consumption and determining the payback period.

The Summary of the Report is:

The aim of the audit is to:

Compute the total auxiliary power consumed and optimizing the auxiliary power consumption.

Studying load patterns and suggesting the optimum load

Comparison of the performance parameters of individual equipment with design value.

Observations and Recommendations:

Load factors of CWP, BFP AND IDF are respectively 75%, 60-70%and 80% respectively.

FD fan of units 1,2,3 have very low load factor (18%-28%), Unit 3 FDF motor (800 KW) is

recommended to replace with 400 KW motor accounts for annual energy saving of 2968 mwh

per year.

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PAF

12%

IDF

12%

FDF

2%

BFP

28%

GT VAT

15%

CEP

2%

ESP

1%

CO M LT

1%COM HT

2%

BCWP

1%

MILLS

10%

CWP

12%

LT DRV

1%

MISSCL

1%

In ash disposal plant, 12 ash disposal pumps are driven with V-belts should replace with flat

belts accounts for annual energy saving of 1106 MWh per year and pay back in 3 months.

It is recommended to replace PT connected at station transformer as it experiencing over

burden.

The flow of flue gases flowing through passes of ESP is unequal. Hence the flow of flue gases

should be regulated to make the flow equal in all passes of ESP. This will improve ESPs

performance.

Ash to water ratio of stage 1 ash slurry pumping system ranges from 1:15 to 1:19. It can be

brought down to 1:10 by regular monitoring thereby 315 million cu.m/year water can be saved.

Suitable Non returning value (NRV) may be replaced at Screen Wash Pump unit 3 to save

254cu.m/hr water discharge when SCW was not in operation.

Total power consumption:

The total power consumption per day is

Calculated and is 2844.76kWh.

Most energy is consumed by BFP Boiler Feed

Pump, which consumes 28.40% of the total consumption.

Auxiliary power consumption is calculated as

APC = {P.G + P.I}-{P.E}

P.G = Power Generated by plant.

P.I = Power Imported into the plant.

P.E = Power Exported by the plant.

The auxiliary power consumption obtained is 11%

Action:

BFP is used to lift the feed water to the boiler. BFP system consists of two pumps each

pump delivers 350 tons/hr and each pump consumes 4 MW. The power consumption of the pump is

300 A. As a part of the process, Cartridge inside BFP is completely changed spending 50 lakhs and

recycling value is also changed spending 10 lakhs. The current consumption is reduced to 260A from300A. The pay back period is 5 to 6 years.

Flat Beltsare used in the place ofV-belts at Ash Slurry Disposal Pump saving 1106 MWh per

annum.

Non returning valve is provided at unit 3of SCW

Boiler heating surface area is replaced

Over hauling of LT and HT pumps.

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