College Papers

YD be fueled by a given source, to

 

 

 

YD Power Plant

 

Natural Gas  Vapor Power Plant

 

 

 

 

Report

on

Cycle and Component Analysis

 

 

 

 

 

 

 

 

 

Yagnadutt
Guduru – 000734312

Aim:

To design and analyze a vapor power plant, that can be fueled by a given
source, to generate a net output of electricity, and operate efficiently.

The aim of this report
is to perform engineering and financial analysis
on a layout of the power
plant design i chose to incorporate in my design for the fictitious company- YD
Power Plant

 

 

Design Considerations:

I was given different sources of fuel to choose from. I had opted to use
natural gas due to its economic value, and is a cleaner source of fuel for its
energy content. Many power-plants in the southern Michigan area use natural gas
as a source of production of electricity as well.

For my plant, I decided
to produce a net output target of 10MW of
electricity. This was not
arbitrarily chosen, but by careful consideration of the given costs, components
and their efficiencies and capabilities involved. After numerous calculations,
I had arrived at a conclusion that this amount of electricity can be produced
with certain efficiency by using a working fluid mass flow rate of 400 gallons/minute.
To bring about the necessary cooling effects, I choose to use river water instead of cooling towers. The decision is
purely economic. The best solution was found to use river water as the cooling solution.

 

Choosing the
right prodcuts and plant configurations for a project requires an intimate
understanding of customer needs as well as equipment features and benefits. The
path to product and plant configuration selection begins with a set of key
considerations:

Ø 
 What type of power is required?

·       
Electrical Power

·       
Combined heat and power

·       
Mechanical Power

Ø What operating profile is expected?

o   Baseload

o   Cyclic
or seasonal

o   Peaking

o   Stand-by

o   Ancillary
Services

Ø How much power is desired?

Ø Is speed to power online critical?

Ø Is a waste gas or alternative fuel
available?

Ø Options to extend existing plant
capability

 

 

 

 

 

 

Natural Gas Vapor Power plant

Benefits

Increased reliability

lower cost

reduced emissions

 

Why natural Gas?

 

 

 

 

 

Key factors to be addressed during the site selection

Typical critical project parameters
that will impact the site selection

ü  Type of natural gas-fired power plant
to be installed

ü  Initial plant capacity and the future
phased installation of additional capacity

ü  Power purchaser’s dispatching
requirements

ü  Natural gas supplier’s guaranteed
quality, delivered pressure, reliability of supply and the commercial terms
associated with each guarantee.

ü  The quality, delivered cost, and
reliability of supply for all potential sources of water, includinggrey water.

ü  Annual variations in site ambient
conditions, site elevation, site soil conditions, site preparation requirements
and seismic zones.

ü  Type and extent of emissions control
equipment and offsets needed to comply with site-specific permitting
requirements.

ü  Plant performance based on heat and
water balances at all anticipated operating modes.

ü  Natural gas supply

ü  Water-related issues

ü  Emissions control and equipment and
offsets

ü  Local government approvals

ü  Site control

ü  Additional Site-Related Studies

•      
A
geotechnical analysis to define foundation requirements

•      
Infrastucture
Analysis to asses the need for on-site and off-site improvements

•      
A
flood risk analysis to establish site elevation, fill and grading requirements

•      
Storm
water runoff analysis

•      
Wetland
analysis

•      
Archeological
investigations

•      
Endangered
species study

•      
The
need for on-site housing for permanent O & M staff and incentives to
attract staff to remote sites.

ü  Gas production stages as follows

Layout:

The layout of the power plant selected involves to have a reheat-regenerative vapor power cycle, consisting of two feed water heaters (a
closed feed water heater and an open feed water heater), two turbines (a high
pressure turbine, and low pressure turbine), a condenser, boiler
(with combustor integrated), and  two pumps.
The schematic of the layout is given below.

 

 

 

Water Requirements

Different water
sources were investigated during the project design phase including

Ø Ground water

Ø River water

Ø Effuent city water

Ø Treated city water

Selection of
water option is based on

Ø Water availability

Ø Economics

Ø Minimize treatment

Ø Reducing & recycling water

Ø Reliability

Ø Reducing waste water
discharge

 

Natural Gas power plant arrangement

 

 

 

 

 

 

 

 

 

Component Selection:

The following are the components
chosen for my design layout.

 

 

 

Based on the above components and
layout,  T-s diagram as follows.

 

 

 

 

The above schematic is only
displayed to enhance the understanding. The values presented were not accurate
in the schematic.

Engineering Analysis:

Using the above T-s diagram for calculating the engineering values, the
following were achieved. The inlet temperature to the HP turbine as 360 0C
for reasons that the boiler combustion gas inlet may be at the maximum
operational range of the boiler.

With regards to mass flow rate of the working fluid. I found it would be
much better off with cooling capacities and economy using a mass flow rate of
400 gallons/minute; i.e,

25.27 kg/s of working fluid.

 

Targets:

 

Required
Wnet

10

MW

Power Before
Generator Wcycle

11.76

MW

 

Wcycle is the power produced from the cycle, just before the generator.
Since the generator operates with its own efficiency, we need to find out how much is produced
at the Wnet stage after the generator. From the cycle itself, the above would be our target. The simulation values were found to be the following.

 

 

 

 

State

Temperature C

Pressure
Mpa

enthalpy(h)
kJ/kg

entropy(s)
kJ/kg K

1

360

6

3071.1

6.3782

2

 

2

2818.114

6.3782

3

 

1

2778.11

6.586

4

320

1

3093.9

7.1962

5

 

0.5

2922.901

7.1962

6

 

0.01

2370.758

7.479759

7

 

0.01

191.83

0.6493

8

 

0.5

192.325

0.6499

9

 

0.5

640.23

1.8607

10

 

6

646.2393

1.861332

11

180

6

769.0428

2.140001

12

 

2

908.79

2.4474

13

 

0.5

908.79

2.4474

On production of the above table, it becomes easier to calculate the net
power output, thermal efficiency, pump work, heat dissipated in the condenser
etc. The following values have been achieved.

 

 

Work Developed in first turbine

 

Work Developed in second Turbine

Wt1/m1

290.4168

kJ/kg

 

Wt2/m1

595.3792

kJ/kg

Wt1

5.274615

MW

 

Wt2

10.81341

MW

 

 

 

 

 

 

 

For First pump

 

 

For Second Pump

 

Wp1/m1

0.390318

kJ/kg

 

Wp2/m1

6.0093

kJ/kg

Wp1

0.007089

MW

 

Wp2

0.109142

MW

 

 

 

 

 

 

 

Work Developed in Cycle

 

 

 

 

Wcycle/m1

879.3964

kJ/kg

 

 

 

 

Wcycle

15.97179

MW

 

 

 

 

 

 

 

 

 

 

 

Heat Added

 

 

Heat Out

 

 

Qin/m

2597.536

kJ/kg

 

Qout/m

1718.14

kJ/kg

Qin

47.17703

MW

 

Qout

31.20524

MW

 

 

 

 

 

 

 

Thermal Efficiency

33.85502

 

 

 

 

 

 

 

 

 

 

 

Net Work

 

 

 

 

 

W

13.57602

MW

 

 

 

 

 

As can be seen from the adjacent
table, The target had been achieved.

 

Now, YD Power plant produce 13.57MW
of electricity with a thermal efficiency of approximately 33.85%.

Cooling
Options:

Based on the above values for heat dissipation at the condenser
Qout=31.20MW. The river could bring about effective dissipation of 31.20 MW. On extensive
calculation, it was
also found that 3
cooling towers would bring about cooling effects
as well. The decision to choose among the two was purely economic.

The mass flow rate of river was sufficient, and within limits of the
maximum flow rate available. River is at 11166.26
gallons/minute, which is still below 12,000 gallons/minute limit. After
financial analysis, it was found that river
provided the best “Return on Investment” time, and is more economic towards
progressive  profit.

 

Exergy Analysis:

The following
are the exergy analysis made using the following assumptions: To = 295K

Po = 1 atm

 

 

Turbine1 Exergy flow

 

 

 

 

Turbine2 Exergy flow

 

 

 

 

ef1-ef3

23164948.5

6.434708

MW

 

 

ef4-ef6

52751270.9

14.65313

MW

Exergy destruction

 

 

 

 

Exergy destruction

 

 

 

 

ED turbine 1

4008104.58

1.113362

MW

 

 

ED turbine 1

5469365.39

1.519268

MW

Exergetic Efficiency for turbine 1

 

 

 

Exergetic Efficiency for turbine 2

 

 

 

E

 

0.819713

 

 

 

E

 

0.737959

 

 

 

 

 

 

 

 

 

 

 

 

Pump1 Exergy Flow

 

 

 

 

Pump2 Exergy Flow

 

 

 

 

ef7-ef8

43937.9172

0.012205

MW

 

 

ef9-ef10

405102.264

0.112528

MW

Exergy destruction

 

 

 

 

Exergy destruction

 

 

 

 

ED turbine 1

11572.968

0.003215

MW

 

 

ED turbine 1

12190.193

0.003386

MW

Exergetic Efficiency for pump 1

 

 

 

Exergetic Efficiency for pump2

 

 

 

E

 

0.580833

 

 

 

E

 

0.969908

 

Boiler Analysis:

 

 

 

 

 

 

In analyzing the boiler i had encountered a typical situation. To facilitate heat transfer
to occur to the working fluid, the combustion
gases need to have certain mass flow rate. This unknown quantity, coupled with
the unknown exit temperature implies a problem. I had developed a relation to FIX the outlet temperature to the stack,
and then derive
the required mass flow rate. For this case,  ASSUMING the stack
temperature to be 500K, and then derived
the required mass flow rate of combustion gases. The following shows the calculations:

 

The boiler from the calculation as an exergetic efficiency of 91.4%, with
the effective heat transfer to the working fluid of 76.3MW.

Exergy Balance:

With the above table showing the
exergy carried in by the combustion products in MW, exergy balance chart as
follows:

 

 

Exergy Analysis

 

 

 

MW

%

Exergy Carried In

28.8966

100

 

 

 

Net PowerOutput

15.79

54.64311

Losses

 

 

Condensor Cooling

2.02

6.990442

Destruction

 

 

Boiler

3.16

10.93554

Turbine

2.64

9.136023

Condensor

5.28

18.27205

Pump

0.0066

0.02284

 

28.8966

100

 

 

Financial Calculations:

For the financial calculations and return on investment time period, assuming
an initial simple interest of 5% towards initial construction and component
cost. The total expenditure is then divided into capital cost, and monthly
operational cost. I had to set a competitive selling price of 0.11 Watsons
per kWhr of electricity consumed
by consumers.

The following
chart potrays the analysis and return on investment.

 

Financial
Considerations

 

 

Component

Product

Cost

Boiler

2

1,500,000

HP Turbine

2

2500000

LPTurbine

1

1500000

Condensor

3

4500000

Pump1

1

1000000

Pump 2

2

2000000

Generator

1

1000000

 

Total

14,000,000

 

 

 

Cost Analysis

 

Revenue

 

 

 

Device Cost

 

14,000,000

River Cost

 

0

Total One time cost

 

14,000,000

 

 

 

Monthly Cost

 

 

Mass flow rate

 

1000

Environmental Fine for river

 

20000

Natural Gas

 

909906.47

Fine for Natural Gas

 

10000

Total Monthly

 

940906.47

 

 

 

Interest

 

5%

 

 

750000

Interest per month

 

62500

 

 

 

Energy Generated per month

 

9774737.3

Selling Price

 

0.11

Revenue Per Month

 

1075221.1

 

 

 

Revenue after interest

 

71814.635

Return on investment(years)

 

16.245528

 

 

 

From the above,
The Least Return on Investment Period is 16.24 years. The best selling price
per kWhr is competitively set at 0.11 Watsons.

permits

Ø  CAFRA
Individual Permit

Ø  Freshwater
Wetlands Permit

Ø  Flood
Hazard Area permit

Ø  Strom
water Management Approval.

 

 

 

 

 

 

 

 

Power plant integration and
Flexibility

 

 

Operational Flexibility

 

Conclusions and future modifications required:

·      
I had reached the target
goal of 10 MW electricity production. Currently, generating

14.87 MW of electricity, with a
thermal efficiency of about 33.85%.

·       The river water as a cooling
method is more economical than cooling towers.

·       It is
recommended to increase the operational temperature ranges in all the
components to further reduce and utilize the exergy (upwards of 80%) lost in
cooling the heat content from the fuel source.

·       In analysis
of the boiler, it was assumed the stack output temperature, and then
opted mass flow rate arbitrarily for the combustion products.

 

A sample actual analysis of the Natural Gas-Fired
Steam Plant

300-MW Natural Gas-Fired Power plant-Costs in three
different countries.

 

 

 

 

Size Classification for cost estimate

 

Emission Standards or
Guidelines.

 

Anticipated Emission control
processes.

Implementation schedule

(1) Power Station

 

Construction Schedule for Key Power
plant Components

Component

Initial Schedule

Final Schedule

No.1 Gas turbine generator

30 months

23 months

No.2 Gas turbine generator

32 months

27 months

Steam turbine generator

42 months

36 months

 

 

Factors that Drive
Power Plant Costs

 

The major factors that need to be taken into account that determine the
costs of building and operating power plants are as follows:

 

·       Government incentives

·       Capital (investment) cost, including
construction costs and financing.

·       Fuel costs

·       Air emissions controls for natural
gas plants.

 

Government Incentives

Many government incentives influence the cost of generating electricity.
In some cases the incentives have a direct and clear influence on the cost of
building or operating a power plant, such as the renewable investment tax
credit.

·       Renewable Energy Production Tax Credit

The credit has a 2008 value of 2.0 cents per KWh, with
the value indexed to inflation. The credit applies to the first 10 years of a
plant’s operation. As of October 2008 the credit is available to plants that
enter service before the end of 2009. The credit is currently available to new
wind, geothermal, and several other renewable energy sources.

 

State and Local Incentives

State and local governments can offer additional
incentives, such as property tax deferrals. The combined value of the
government tax breaks can run into the hundreds of millions of dollars per
project. For example, Duke Energy’s Edwardsport IGCC project in Indiana is
expected to receive almost half – a – billion dollars in federal, State, and
local tax incentives.

 

State utility commission can use rate treatment of new
plants as a financial incentive for the investor owned utilities they regulate.
Under traditional rate making a utility is not permitted to earn a return on
its construction investment until a plant is in service. This approach to rate
making is used to motivate the utility to prudently manage construction, and to
ensure that customers do not have to pay for a power plant until it is
operating.

 

 

Financing Power
Plant Projects

 

Three types of entities typically develop power plants:

 

·       Investor-owned utilities (IOUs)

·       Publicly -owned utilities (POUs)

·       Independent Power Producers (IPPs)

To assimilate the importance of the
concepts that i was talking above, a small real scale estimation is provied in
the following table.

 

 

Generation

Generating Capacity

Publicly-Owned
Utilities

22%

21%

Investor-Owned
Utilities

41%

38%

Non-Utilities

37%

41%

National Total

100%

100%

Source:
American Public Power Association, citing Energy Information Administration.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fuel and allowance Price Projections
(Selected Years)

 

 

Impact

 

That
the project has met its overall goal is evident from the fore-going comments.

Several favorable factors have
contributed to this result. Project implementation coincided with the review of
rigid norms relating to allocation of output of power stations owned by the
central public sector undertaking between the states constituting the ‘region’.
This flexibility enabled to purchase of all the capacity and output of the
plant and led to satisfactory commercial arrangements. Robust economic growth
is yet another favorable circumstance.

 

                      All
thermal power generation involves emissions into the environment but these are
relatively less in the case of the plants using a clean fuel like natural gas.
It is seen that in actual operation also, this plant has conformed to the
emission norms stipulated by the concerned authorities. As regards project
design and scope, limitations imposed by available natural reserves of gas
would have influenced the plant scale and design. It is notable that owing to
efficient operations, the price per unit of electricity generated by this plant
has been coming down. This added proof of the effectiveness of the plant in
achieving the project purpose.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

1 Hammond and Ondo Akwe, 2007 G. P.
Hammond, S.S. Ondo Akwe

Thermodynamic and related analysis of
natural gas combined cycle power plants with and without carbon sequestration.

 

2 Minton, 1986 P.E. Minton

Handbook of Evaporation technology,
Noyes Publications, Park Ridge, N.J., U.S.A. (1986).

 

3 X Shi B Agnew, D Che

Proceedings of the Institution of
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Thermal performance of gas turbine
power plant based on exergy analysis.

 

5 Gowtham Mohan, Sujata Dahal, Uday
Kumar, Andrew Martin, Hamid Kayal

Development of Natural Gas Fired
Combined cycle plant for Tri-Generation of Power cooling and Clean Water Using
Waste Heat Recovery: Techno-Economic Analysis.

 

6 Juan Pablo Gutierrez, Elisa
Liliana Ale Ruiz, Eleonora Erdmann

Energy requirements, GHG emissions
and investment costs in natural gas sweetening processes.

 

7 Mehdi Mehrpooya, Mohammad Mehdi,
Moftakhari Sharifzadeh

Conceptual and basic design of a novel
integrated cogeneration power plant energy system.

 

8 Zhenying Wang, Xiaoyue Zhang,
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Waste heat and water recovery from
natural gas boilers: Parametric analysis and optimization of a flue-gas -driven
open absorption system.

 

9 Suvorov D. M., Tatarinova N. V.,
Krupin D. F., Suvorova L.A., Baibakova T.V..

Energy and Economic Efficiency of Gas
Turbine Units and Heat Pumps in power-supply systems in the Arctic Regions of
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10 Energy Information
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production by source, Selected Years, 1949 – 2011.

 

11 Energy Information
Administration. 2012. Natural gas Gross Withdrawals and Production.

 

12 MIT Energy Initiative. 2011. The
Future of Natural Gas.

 

13 US Department of Energy. 2013.
Natural gas. Online at:
http://fossil.energy.gov/education/energylesssons/gas/index.html.

 

14 American gas Association.
2011.DOE to Issue Direct Final Rule (DFR) on Residential Furnaces Mandating 90%
AFUE Furnaces in the “North”.

 

15 Energy Information
Administration. 2012. Natural Gas consumption by End Use.

 

16 US Environmental Protection
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17 Natural Resources Defense Council.
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18 Sara Thyberg, Department of
Chemical Technology, Royal Institute of Technology, S-100 44 Stockholm, Sweden

Feasibility Studies of High
Efficiency AFC Power Plants for Natural Gas.

 

19 performance and cost estimation
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Canary Islands, Spain, 2010.