Carbon Credit_illustration Through HYSYS Simulation

8/9/2019 Carbon Credit_illustration Through HYSYS Simulation

1/27

CARBON CREDIT- A New Measure to Shed off GHG Emission

Subhasish Mitra

M.Tech

Department of Chemical Engg, IIT Kanpur


2/27

Combined power cycle: Brief Recap

Brayton cycle

Rankine cycle

Fuel used : Natural Gas

Plant capacity : 400 MW


3/27

Power Plant Process Flow Diagram-Base case CCS facility excluded:

Steam boiler

Gas Turbine Block

HP Steam turbine LP Steam turbin

Steam condenser

Flue gas disposed tostack GHGs emission.


4/27

CO2

Emission A Known Nuisance

1. CO2 is the ubiquitous Green House Gas and liable for globalwarming.

2. Fossil fuel powered power plants are the epicenters for CO2

emission due to voluminous flue gas disposal beside other

industries, automobiles and residential release.

3. Major concern is observed in the recent past to reduce CO2

emission through various measures and policy formulation (e.

Kyoto protocol).


5/27

Brief Case Study:

Govt decided to put mandate on implementing CO2

capture facility at the power plant site.

Normal emission limit from power plant : 1.65 to 1.95

million ton CO2/yr.

Emission limit posed by EPA is 7% reduction on 1990

emission figure of 0.479 tons of CO2/MWh generated

which translates to 1.425 million ton CO2/yr for our plant.

Plant capacity : 400 X8000 Mwh/yr


6/27

Where does our plant stand?

CO2 Emission : 4079 kmol/hr which translates to 1.44million ton CO2/yr.

The plant exceeds EPA recommended limit by 0.012

million ton CO2 p.a.

Since CO2 emission by the plant is more than EPA

recommendation, so plant decides to invest upon CCS to

earn CARBON CREDIT.


7/27

What is Carbon Credit?

An instrument created to represent one metric ton of CO2 avoided

or removed by a carbon reducing project.

Some definitions:

Key component of national and international attempts to mitigate t

growth in concentrations of (GHGs). One Carbon Credit is equal to

one ton of Carbon.

A "credit" to emit a ton of carbon dioxide (CO2) issued as part of anemissions trading scheme such as the European Emissions

Trading Scheme.


8/27


9/27

Company adopts this CCS scheme

NG toPower Plant

To Oil/Gasreservoir for EOR

Oil out

Void oil/gaswell for

storage

Amineabsorptionplant


10/27

Amine absorption plant simplified PFD:


11/27

CCS Project Feasibility Analysis:

A Hysys simulation is made to study the feasibility of

integrating proposed CCS process with the existing plant.

Major challenge is to provide huge thermal energy to the

stripper reboiler. Even auxiliary boiler is also reported.

But simulation shows reboiler demand can be internallymet.

Around 85% CO2 scrubbing efficiency is obtained from

simulation.

With all economic analysis, it turns out that project is

feasible.


12/27

Power Plant Process Flow Diagram-Modified case CCS facility included:

Stripper reboilersteam is supplied

from the partiallyderated LP steamturbine.

CCS unit: Fluegas compression,absorption &transportation


13/27

CO2 absorption unit:

Steam to stripperreboiler suppliedfrom LP steam

turbine O/L.


14/27

CO2 Transportation Unit:

Transport pump

Transportcompressor


15/27

0.55Combined cycle efficiency

0.284Rankine cycle efficiency

0.37Gas turbine cycle efficiency

0.45Overall efficiency

MW1072.65Heat input by NG@LHV

MW1.585Condensate pump

MW283Boiler heat input

MW136.2Compressor

MW16.63ST-2 output

MW65.31ST-1 output

MW400GT output

Energy efficiency before CCS

Energy Efficiency Before Implementing CCS:


16/27

Energy Efficiency After Implementing CCS:

%15.56Efficiency reduction

0.38efficiency

MW1072.65Heat input by NG@LHV

MW1.432Transport pump

MW18.42Transport compressorMW0.102Lean amine pump

MW0.067Rich amine pump

MW47.94Flue gas blower

MW283Boiler heat input

MW1.585Condensate pump

MW136.2Compressor

MW9.869ST-2 output

MW65.31ST-1 output

MW400GT output

Energy efficiency after CCS


17/27


18/27

Important Facts Behind Economic Analysis:

Price hike in electricity follows yearly compounding,

i.e. P1 = P(1+i)n and stops at break even point. n = no of years.

Straight line depreciation model is followed.

Payback period is calculated as

Capital Investment/(Carbon Credit Earned + Depreciation/yr)

ROI = (Net Profit/Capital Investment) x 100

Credit from injecting CO2

for EOR not considered.

Decline in Carbon credit due to escape from sequestration not

considered.


19/27


20/27

Cooling Utility Cost for CCS:

4.02 million $Total

175243.3941043.120.02110Compressor stage-4cooler

102166.898608.140.0215.83

Compressor stage-3

cooler

102236.996608.550.0215.834

Compressor stage-2

cooler

115275.104686.180.0216.578

Compressor stage-1

cooler

330684.2841968.360.02118.87Precooler

314737.1351873.440.02117.96

Stripper column

condenser

2884506.25917169.680.021164.6

Flue gas blower

aftercooler

Total coolingcost ($/yr)

CW flow

rate (t/hr)

Cost $/ton of

CW

Equipmentcooling duty

(MW)Cooling cost

Cooling water Delta T = 80C, Sp. Heat capacity = 4.314 KJ/Kg/K


21/27

60.34 million $Total

1266666.6670.091.76Transport pump

16323555.560.0922.67Total compressor power

2.68Transport compressor ST-4




90666.670.090.13Lean amine pump

59511.110.090.08Rich amine pump

42604444.440.0959.17Flue gas blower

Total cost ($)/yrElectricity cost

($) / kwhCapacity (MW)Equipment

Electricity consumption cost for CCS:


22/27

Raw Material Cost:

529.5 ton1.72.42688350MEA make up

10 min

(assumed)

Absorption

loop inventory

Total cost

(million $/yr)

Unit cost

($/kg)Qty (kg/hr)

Raw material cost

Basis:

Make up is replacement of degraded MEA

MEA degradation rate : 2.5 wt% / week

Absorption loop inventory : 10 min

*Total Carbon Reduction Cost :

$ 56.8 million/Ton of CO2

*5% contingency cost is included.

Reported CO2 reductio

cost in literature:$37-74/ton of CO2


23/27

Expenditure Summary for CCS:

yrs6.14Payback period

million $18.62Carbon credit earned/yr

million $13.44Revenue after Tax deduction

%10Tax deduction

million $9.61Taxable revenue

million $14.4Revenue/yr through electricty

% pa5Hike in electricity price

million $4.87Revenue lost/yr

Mwhr6.76Electricity generation reduced

million $4.79Depreciation/yr

million $0Salvage value

years30Plant life

million $69.54Annual Carbon reduction cost

million $14.36Annual loan installment

%15Bank loan interest rate

10Loan repayment duration (Year)

million $143.6

Investment cost


24/27

CCS P j b k l i


25/27

CCS Project break even analysis

-60

-40-20

0

20

40

6080

100

120

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 Y9 Y10

Production cost

Revenue after ta

ROI

Hike in electricityprice stopped.

Break even

point at ~ 6 yrs

Costfigures

inmillion$/%

ROI


26/27


27/27

Documents

Carbon Credit_illustration Through HYSYS Simulation