YD Power Plant
Natural Gas Vapor Power Plant
Cycle and Component Analysis
Guduru – 000734312
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
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.
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
What type of power is required?
Combined heat and power
Ø What operating profile is expected?
Ø How much power is desired?
Ø Is speed to power online critical?
Ø Is a waste gas or alternative fuel
Ø Options to extend existing plant
Natural Gas Vapor Power plant
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
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
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
ü Local government approvals
ü Site control
ü Additional Site-Related Studies
geotechnical analysis to define foundation requirements
Analysis to asses the need for on-site and off-site improvements
flood risk analysis to establish site elevation, fill and grading requirements
water runoff analysis
need for on-site housing for permanent O & M staff and incentives to
attract staff to remote sites.
ü Gas production stages as follows
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.
sources were investigated during the project design phase including
Ø Ground water
Ø River water
Ø Effuent city water
Ø Treated city water
water option is based on
Ø Water availability
Ø Minimize treatment
Ø Reducing & recycling water
Ø Reducing waste water
Natural Gas power plant arrangement
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.
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.
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.
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
For First pump
For Second Pump
Work Developed in Cycle
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%.
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
are the exergy analysis made using the following assumptions: To = 295K
Po = 1 atm
Turbine1 Exergy flow
Turbine2 Exergy flow
ED turbine 1
ED turbine 1
Exergetic Efficiency for turbine 1
Exergetic Efficiency for turbine 2
Pump1 Exergy Flow
Pump2 Exergy Flow
ED turbine 1
ED turbine 1
Exergetic Efficiency for pump 1
Exergetic Efficiency for pump2
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.
With the above table showing the
exergy carried in by the combustion products in MW, exergy balance chart as
Exergy Carried In
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
chart potrays the analysis and return on investment.
Total One time cost
Mass flow rate
Environmental Fine for river
Fine for Natural Gas
Interest per month
Energy Generated per month
Revenue Per Month
Revenue after interest
Return on investment(years)
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.
Hazard Area permit
water Management Approval.
Power plant integration and
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
300-MW Natural Gas-Fired Power plant-Costs in three
Size Classification for cost estimate
Emission Standards or
Anticipated Emission control
(1) Power Station
Construction Schedule for Key Power
No.1 Gas turbine generator
No.2 Gas turbine generator
Steam turbine generator
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
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
· 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
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.
American Public Power Association, citing Energy Information Administration.
Fuel and allowance Price Projections
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.
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.
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