hubco narowal power plant internship report

7/24/2019 HUBCO Narowal Power Plant internship report

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HUBCO NarowalInternship Report

Omar Farooq 2011906 9/1/15


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Plant layout of HUBCO power plant and

Specification of plant machinery

HUBCO Narowal Power Plant is a 225 MW power generation facility, located 16 km from Narowal city,

Punjab Pakistan. The site was built by MAN Germany and handed over to HUBCO in 2011. Plant

operations are overseen by TNBRP, a Malaysian firm. The facility cost 315.6 Million (EUR = 36.14 Billion

PKR @114.5 rate). Net output of the power plant is 213.603 MW, which equates to 169.2 Million

rupees per installed MW capacity. For comparison, the Tarbela Dams cost today is 10.37 Billion USD (=

1.06 Trillion PKR @101.7 rate). Net output of tarbela dam is 3478 MW which gives 303.3 Million rupees

per installed MW capacity.

Plant layout of HUBCO Narowal power plant

HNPP is a combined cycle diesel engine power plant. It has 11 diesel engines running on heavy fuel oil

(HFO). Exhaust gases from each diesel engine is fed to a heat recovery steam generator or HRSG (a

boiler), which produces steam to power a steam turbine. This combined cycle power generation system

is illustrated in a diagram on the next page.


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Maximum Power output Capacity:

18.9*11 + 16.34 = 224.24 MW

The combined cycle results in an increased overall efficiency, and was a condition for the loan obtained

from the World Bank.


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Tank Yard

Heating

and

decanting

Engineradia

tors

Engine

room 1

Engine

room 2

Steamturbine

area

Condenser

room

Grid station

Control

room

building

Compres-

sor room

Engineauxiliaries

Engineauxiliaries

HRSGs(Boilers)

HRSGs(Boilers)

Exhaust

gasstacks

Exhaust

gasstacks

HUBCO

office

Workshop building

TNBRP

office

Fuel

treatment

room

Water

treatment

room

Firefigh-

ting

room

Gate#.3

Towards

HUBCO colony

Towards

MAN

l

Towards

Ataltec

colony

Wastewater

treatment

plant

Warehouse


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The Diesel enginesEach of the engines present at HUBCO is a MAN turbocharged medium speed diesel engine. The engine

model is 18V48/60

The engine running speed is 500 rpm (hence a medium speed engine), the mean effective pressure is

23.21 bar, and the effective power at crankshaft is 18.9 MW. The engine drives an alternator which

produces electrical energy. As alternators have an efficiency >98%, this can be considered to be the

same as the electrical power output per engine.

Weight of the Engine is 255 Ton, while that of the crankshaft alone is 20 Tons! This helps illustrate is

massive size!

The Steam Turbine

The Steam Turbine is a 2 stage Dresser-Rand (Peter Brotherhood) turbine rated at 16.34 MW. The

turbine along with its auxiliaries is shown in the figure on the next page. The functions and operating

procedures are discussed below.

The turbine is started on auxiliary oil pump. DC oil pump is a standby pump which kicks into action if the

auxiliary oil pump fails. Auxiliary oil pump provides lubrication to the bearings when the turbine is in

barring. The lube oil pump is used when the turbines rpm is increased from barring to the regular

operating speed. After the turbine has been on lube on full speed for some time, it is shifted to the mainoil pump instead.

When the turbine is started, it does not go from 0 to 6000rpm in a go. Instead, it is first taken from stop

to barring and maintained for 5 hrs with a 230 rpm, and then taken to full speed. Sudden change in

operating temperature of the turbine is avoided in order to reduce effect of any thermal shock, which

may not only crack the blades, but also decrease the life of the overall machine.

18V 48 60

Number of

cylinders

Bore

Diameter* Stroke length*

*in cm

Engine type


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How diesel engine combined cycle is better

than gas turbine combined cycle Power Plants

Combining two or more thermodynamic cycles results in improved overall efficiency, reducing fuel costs.

In stationary power plants, a widely used combination is a gas turbine (operating by the Brayton cycle)

burning natural gas or synthesis gas from coal, whose hot exhaust powers a steam power plant

(operating by the Rankine cycle). Combined Cycle Gas Turbine (CCGT) plant can achieve a best-of-class

real (HHV) thermal efficiency of around 54% in base-load operation, in contrast to a single cycle steam

power plant which is limited to efficiencies of around 35-42%.

The Comparison

Comparison Criteria selection of power plant type is based on thermal efficiency, cost-effectiveness, and

environmental impact. The performance parameters, i.e., thermal efficiency and heat rate are the most

important factors in evaluation and comparison of various types of power plants. High efficiency is the

primary prerequisite for making an economical choice of power plant. Thermodynamic superiority of

combined-cycle power plants is their outstanding feature.

In combined cycle power plants, the efficiencies of diesel engines, steam power plants and single-cycle

gas turbine power plants are surpassed. The best gas-fired steam power plants can attain efficiencies of

about 45%. The simple-cycle advanced gas turbine efficiency at a turbine inlet temperature of over 1100

degree Celsius is around 3738.5%, whereas advanced combined-cycle power plants attain efficiencies

of or even higher (up to 58-60%).

Let us consider the following type of power plants:

1.

steam turbine2.

gas turbine

3.

diesel engines

The efficiencyof advanced diesel engines is comparable to that of gas turbines of equal power capacity,

and therefore diesel engine power plants may appear to be the optimum option for smaller to medium

power outputs, e.g., up to 30 MW, and in the most favorable Cases, even up to 50 MW.


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At higher capacities, diesel engine power plants have highercapital and maintenance coststhan gas

turbine power plants.

However, diesel engines have greater environmental impact, especially with the emissions of NOx and

unburned hydrocarbons.

Specific capital costs per kW of power output of combined-cycle power plants increase as the plant

power rating decreases. Therefore combined-cycle power plants of smaller power outputs are suited for

industrial or district heating cogeneration plants. However, the minimum economical size of the

combined-cycle cogeneration plants based on the utilization of gas turbines is 10 MW. Power rating of

diesel engines is even greater, in order to have sufficient amount of exhaust gases to be utilized by a

HRSG unit.

The second important criterion for comparing types of power plants is the economic factor.

Steam power plants are significantly more expensive than combined-cycle power plants. A coal-fired

power plant, for example, costs 2-3 times as much as a combined-cycle power plant with the samepower output.

Advanced combined-cycle power plants are therefore simpler and less expensive than steam

power units.

Their construction period is shorter than that of steam power plants.

A possibility of progressive staged construction of combined-cycle power plants is yet another

advantage. At the first stage, the gas turbine plant is installed and commissioned. During the

second stage, the steam plant train is installed. Construction costs of the steam plant will be

financed from the revenues of electric power produced by the gas turbine plant.

Comparing both the performance and economic criteria shows that combined-cycle power plants have

an evident advantage over simple-cycle plants such as steam or gas turbine power plants.

Therefore combined-cycle power plants represent the optimum energy system type that is suitable for

the construction of new power plants and for upgrading and of existing steam power plants.

Operating Costs

Because of the high reliability of advanced gas turbines, simple-cycle gas turbine plants have the lowest

operating and maintenance (O and M) costs, although they require more spare parts than steam

turbines. A steam power plant requires more staff, and its maintenance costs are higher.

O and M costs of combined-cycle power plants depend on the complexity of the steam portion and are

between those of simple-cycle gas turbine plants and steam power plants.


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Availability and Reliability

Major factors determining power plant availability are

Design of the major components

Mode of operation (base, medium, or peak load)

Type Of fuel

All the power plants under consideration have similar availabilities when used under the same operating

conditions. Typical figures for the availability of base-load power plants are as follows:

gas-fired gas turbine power plants 8895% -

Oil- or gas-fired steam turbine power plants 85-90%

coal-fired steam turbine power plants 8085%

gas-fired combined-cycle power plant 8590%

The availability of peak and medium load machines is lower because of frequent start-ups and

shutdowns that reduce life of the machine and thus increase the scheduled maintenance and forced

outage rates. Frequent shut downs has a more detrimental effect on gas turbine power generation units

than diesel engines

Fuel costs

Fuel expenditure of gas turbine power plants are generally greater.

Greater fuel purification is required due to increased instances of corrosion occurrence in gas turbine

engines. Diesel engines on the other hand are insensitive to the presence of impurities such as Metals or

salts in the fuel.

The fuel required is more expensive itself. Unlike steam power plants that can be fired with any fuel or

diesel engines that may run on HFO, gas turbine power plants employ only natural gas or light distillate

(LFO) as fuel. Both of these fuels are more expensive than coal for steam power plants, or HFO in the

case of diesel engines. Fuel price is an essential constituent of electricity costs. Therefore, as a rule, coal-

fired reheat steam power plants produce electricity cheaper but at a higher environmental impact than

power plants based on gas-fired gas turbines.

Among all Oil- Or gas-fired power-stations, the combined-cycle power plant is the most economical

technology for electricity generation. For short utilization periods of peak-load plants with annual

service of up to 2000 h/yr. for gas-fired large-capacity power plants and up to 1500 h/yr. for oil-fired

smaller units, the gas turbine is the most economically viable choice. Coal-fired steam power plants are


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suitable for use as base-load plants if the price difference between the coal and the gas turbine fuel is

sufficiently large (around PKR 300-600/GJ).

Combined-cycle power plants with supplementary firing represent a viable option for re-powering as

well as for application in cases when the gas or oil supply is scarce and the more easily available fuel iscoal for use in supplementary firing.

To summarize, benefits of using diesel engines over gas turbines are as follows:

Instantaneous switchover from gas to fuel oil

Switch fuels while maintaining full load

Insensitive to metals and salts in fuel oils

No increased maintenance needs when running on fuel oil

Fuel sharing operation

Fuel Selection

The selection of the fuel and the corresponding type of power plant is determined not only by short-

term economic considerations also by long-term developments in the prices for the various possible

fuels. In this regard, the following aspects can become important in selecting the type of power plant to

build long-term availability of the fuel at a favorable price and also satisfy environmental concerns.


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Line diagrams, assignment 4

Decanting process: assignment 5

Assignment 6: How maintenance process is executed (PM and CM) which includes work order, issuances

of spares, closing of permit etc


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Conclusion

Overall, my internship experience at HUBCO Narowal was a truly enriching one. I got to see for myself

the operation of a power plant, and since I wish to work in Pakistans energy sector after completing myengineering degree, this was a very meaningful and valuable experience.

hubco narowal power plant internship report

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