Brewery CogenerationA Cogeneration Solution For A Medium Size Brewery

Presented by:Oliver McRae

Professor:Xi Lin

ME304 – Energy & ThermodynamicsWednesday, October 16th, 2013

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Agenda

Background

Project Definition

Data Acquisition, Interpretation & Equipment Selection

Thermal Calculations

Financials

Questions & Feedback

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BackgroundAn Overview Of The Energy Sector In Jamaica

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The electricity sector in Jamaica is in dire straits.

Equipment is aging and results in inefficient power generation.

Fuel cost is high.

Energy theft.

Affects many industries: Healthcare. Education. Manufacturing. Almost all civil services.

Stagnates economic growth.

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Project DefinitionCrafting An Engineering Solution For High Cost Energy

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Red Stripe suffers financially because of the cost of energy.

Red Stripe Jamaica Limited is the Brewer of the world renowned lager, Red Stripe.

Power comes from the Jamaica Public service Company.

Number six heavy fuel oil (process steam) is purchased from the single local refinery PetroJam.

High electricity and process steam requirements.

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Data Acquisition, Interpretation & Equipment Selection

An Examination Of Electrical Demand Requirements & How To Meet It

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Data from the SCADA system was extracted and examined.

Red StripeEnergy

Requirements     

Electricity     HFO  

1,466,282kWh/Month Total Steam 24,069,189kg/year

17,595,382kWh/Year Total Fuel 2,358,095 liters/year

  7,266,076,727Btu/month

     87,192,920,72

0Btu/year

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Two 1.131MW gensets are needed based on the energy requirements.

 ElectricityMean Power

Requirement 2,007.2kWMax Available 2,262.0kW

Propane Air mixer 60.0kW

Required 17,595.4MWhRequired with

mixer 18,121.3MWhMax Available 19,828.7MWh

Capacity Factor 95%

Max Available with cap 18,837MWhAverage

Genset load 96.2%Efficiency 41.5%

Fuel required for electricity

148,994,181,758Btu/year

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The GE Jenbacher JMS 416 is selected because it meets the requirements.

Electrical output 1131kWRecoverable Thermal output 120C 1155kWEnergy input 2636kWFuel consumption 277m3/hrElectrical efficiency 42.9%Thermal efficiency 43.8%Total efficiency 86.7%Exhaust gas mass flow rate, wet 5,993kg/hrExhaust gas volume, wet 4,734m3/hr

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Thermal CalculationsThe Determination Of The Amount Of Process Steam Available From

The Engine

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Calculating steam enthalpy.

Steam Enthalpy  Water   Steam    95C 175.4C, 9 barEnthalpy 398,102 J/kg 2,773,900 J/kgEnthalpy Difference   2,375,798J/kg  Enthalpy Change Required   2251.8Btu/kg  Boiler Efficiency 84%   2680.7Btu/kg  Yearly Steam Demand  

32525684.8kg  

Mean Hourly Steam Demand   3710.4kg/hr  Actual Mean Hourly Steam Demand   2745.7 kg/hr  

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Calculating enthalpy of incoming and outgoing exhaust gas.

Exhaust Gas EnthalpyTemperatur

e (K) Oxygen CO2 Nitrogen    5% 17% 78%Composition

663 19,973 25,314 19,476Molar Enthalpy 1368 10,754 12,074 10,709Molar Enthalpy 2

  32.0 44.01 28.01Molar Mass

663 624.2 575.2 695.3Exhaust Enthalpy 1, Parts

368 336.1 274.3 382.3Exhaust Enthalpy 2, Parts

                  

663 31.2 97.8 542.4Part Enthalpy 1368 16.8 46.6 298.2Part Enthalpy 2663  671.3kJ/kg Exhaust Enthalpy 1368  361.7kJ/kg Exhaust Enthalpy 2

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Energy rate balance.

☙The following formula was used to calculate the available saturated steam at the required pressure of 9 bar.

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Allocating both engine available steam and additional steam.

Primary Heat Exchanger Process Streams   Exhaust Gas     Water/Steam    

  Mass Flow Rate Temperature EnthalpyMass Flow Rate Temperature

Enthalpy

Incoming 11530 663 671.3 1503 368 398.1Outgoing 11530 368 361.7 1503 449 2773.9             

 

Process Steam Available from engine 1503kg/hr

Additional Fuel for Steam 84% efficiency 3,331,476Btu/hr

 Additional Steam required 1243kg/hr  

29,203,718,954

Btu/year

             

 Total fuel required

178,197,900,712 Btu      

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FinancialsThe Confirmation Of The Quality Of This Investment

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Financial metrics validate the undertaking of the project.

CAPEX @ Year 0 ~$401,000,000

IRR Using Future Cash Flows = 83.8%

Savings increase yearly.

Payback happens within two years.

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Current charges in Jamaica.

 Current Electricity per year 17,595,382kWhElec Cost per Kwh $34.88JMDTotal Elec Cost 613,814,481JMDHFO energy content 36,976Btu/LLiters of HFO 2358095LitersHFO Cost per liter $76.34JMD

HFO Cost$180,016,97

2JMD

Total Energy Cost$793,831,45

3JMD

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Projected Project fuel costs in Jamaica.

Propane Energy content 24,225Btu/LFuel required 7,355,950LitersCost per Liter $48.00JMD

Total Fuel Cost353,085,62

4JMDTotal Energy Costs Prime Power

398,909,361JMD

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Project experiences payback in 15 months with a strong IRR.

Year Year 0 Year 1 Year 2

Fuel $0$264,814,21

8 $367,209,049O&M $0 $34,367,803 $47,198,449Expected Expenditure using current procurement $0

$793,831,453 $817,646,397

Capital Outlay$400,886,72

0 $0 $0

Money Paid to Utility $0$198,457,86

3 $23,031,475       

Operating Savings

-$400,886,72

0$296,191,56

9 $380,207,424       

Total Cost for Year$400,886,72

0$497,639,88

4 $437,438,973       

Net Cash Flow

-$400,886,72

0$296,191,56

9 $380,207,424

Net Internal Rate of return 83.8%   

Payback Period 15.3months  

*Abbreviated from 6 years

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Next Steps

Acquire More Data From Red Stripe

Get More Accurate Data From Manufacturers & Model System With Additional Equipment (eg. Steam Accumulator)

Add More Variables To Increase Accuracy

Investigate Grid Tie Solution Implementation

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Questions & Feedback