Small Scale NZ Biofuel Small Scale NZ Biofuel Techno-Economic Techno-Economic InvestigationInvestigation

VISHESH ACHARYAVISHESH ACHARYAMASTER OF ENGINEERINGMASTER OF ENGINEERING

DR. BRENT YOUNGDR. BRENT YOUNGCHEMICAL AND MATERIALS ENGINEERINGCHEMICAL AND MATERIALS ENGINEERING

UNIVERSITY OF AUCKLANDUNIVERSITY OF AUCKLAND

OVERVIEWOVERVIEW

Introduction to Bio EthanolIntroduction to Bio Ethanol Benefits of Blending Ethanol with PetrolBenefits of Blending Ethanol with Petrol Bio Ethanol Manufacturing ProcessBio Ethanol Manufacturing Process Classification of feedstockClassification of feedstock Potential of various Starch, Sugar and Potential of various Starch, Sugar and

Cellulosic materials as Feedstock in NZCellulosic materials as Feedstock in NZ ConclusionsConclusions

What is Bio Ethanol?What is Bio Ethanol?

Alcohol based liquid fuel made from Alcohol based liquid fuel made from agricultural bio massagricultural bio mass

Produced by fermenting sugar from Energy Produced by fermenting sugar from Energy crops crops

EU, USA and Brazil mandate a minimum EU, USA and Brazil mandate a minimum ethanol blend.ethanol blend.

NZ govt mandates selling a minimum of 0.25% NZ govt mandates selling a minimum of 0.25% of all fuel sold to be that of Bio fuels, starting of all fuel sold to be that of Bio fuels, starting 20082008

Benefits of Blending Benefits of Blending Ethanol with PetrolEthanol with Petrol

Contains 35 mole percent OContains 35 mole percent O22

Acts as an oxygenate – facilitates combustion to a Acts as an oxygenate – facilitates combustion to a greater extentgreater extent

Increases energy efficiency by 1%Increases energy efficiency by 1%

EmissionReduction in

Emissions

Carbon Monoxide 25-30%

Carbon Dioxide Up to 10%

Volatile Organic Compounds 7%

SO2 Decrease

Aromatics Decrease

Manufacturing ProcessManufacturing Process

PRE-TREATMENT

ENZYMES

FERMENTATION

ENZYMESYEAST

123

456

123

456

BEER STRIPPER

RECTIFIER

SOLIDS

50% EtOH

10% EtOH

WATER

95% EtOH

DEHYDRATOR

99.6% FUEL GRADE

ETHANOL

AZEOPTROPIC

Feedstock

HYDROLYSIS

Classification of FeedstockClassification of FeedstockClassified into 3 types depending upon the constituent sugars

• SACCHARINE: Directly fermentable 6 and 12 C sugars

Glucose, Fructose and Maltose

E.g. Sugar cane, Sugar beet, Whey, etc.

• STARCH: Carbohydrates such as Starch and Inulin

E.g. Maize, Wheat, Potatoes, etc.

• CELLULOSE: Common material in plants

Primary constituent of plant cell wall

Wood, wood waste, paper, straw, etc.

SACHHARINEFruits Molasses

STARCHGrains Potatoes

CELLULOSEDRY Green

MASHING

DILUTION DILUTION

LIQUEFACTION

MILLING

HYDROLYSIS HYDROLYSIS

PRE TREATMENT SHREDDING

FERMENTATION

DISTILLATION

DEHYDRATION

DENATURING STORAGE

MASHING

DILUTION

Starch CropsStarch Crops Maize, Wheat, Barley and Milo Maize, Wheat, Barley and Milo

(Sorghum) are the most extensively used (Sorghum) are the most extensively used Starch based feedstockStarch based feedstock

Maize is the most widely used feedstockMaize is the most widely used feedstock

Current annual production of Maize Current annual production of Maize based ethanol is ~20 Billion Lbased ethanol is ~20 Billion L

Ethanol from MaizeEthanol from Maize

Ethanol from Maize is produced by 2 methods:

1. Dry Milling

Ethanol - Primary product

Distiller Dried Grains and Solubles (DDGS) and CO2

– Secondary Products

Typical yields: 460 L EtOH/T Maize

380 kg DDGS/T Maize

Dry Milling Process for the production of Ethanol from Maize [Henderson, C. (2006)]

Ethanol from MaizeEthanol from Maize

2. Wet Milling2. Wet Milling

Gluten Feed, Starch, Corn oil, Corn Germ and Corn Syrup Gluten Feed, Starch, Corn oil, Corn Germ and Corn Syrup Liquid – Primary products.Liquid – Primary products.

Starch is further hydrolysed and fermented to EthanolStarch is further hydrolysed and fermented to Ethanol Typical Yield: 440 L EtOH / T Dry MaizeTypical Yield: 440 L EtOH / T Dry Maize Yield lower than Dry milling as some starch is lost in co-Yield lower than Dry milling as some starch is lost in co-

products.products. Process more complex than Dry millingProcess more complex than Dry milling Hence, requires higher capital investmentHence, requires higher capital investment

Wet Milling Process for the production of Ethanol from Maize [Henderson, C. (2006)]

Ethanol from NZ MaizeEthanol from NZ Maize

150,000 tonne Maize grown on 13,000 Ha. of land150,000 tonne Maize grown on 13,000 Ha. of land

NZ Maize yield: 12.5 t/Ha (U.S. Maize yield: 8 t/Ha)NZ Maize yield: 12.5 t/Ha (U.S. Maize yield: 8 t/Ha)

Energy input for un-irrigated arable Maize farming in Energy input for un-irrigated arable Maize farming in NZ : 1683 MJ / t MaizeNZ : 1683 MJ / t Maize

Avg. US Maize farming input : Avg. US Maize farming input : 24252425 MJ / t Maize MJ / t Maize

Cost – Ethanol from NZ Cost – Ethanol from NZ MaizeMaize

Potential Yield: 397 L EtOH / t MaizePotential Yield: 397 L EtOH / t Maize Dry Mill Process, 95 ML/yrDry Mill Process, 95 ML/yr

90.3 NZc/L EtOH90.3 NZc/L EtOH Maize sourced from within 100km @ NZ$10/tMaize sourced from within 100km @ NZ$10/t

Wet Mill Process, 95 ML/yrWet Mill Process, 95 ML/yr 76.6 NZc/L EtOH76.6 NZc/L EtOH Maize sourced from within 100km @ NZ$10/tMaize sourced from within 100km @ NZ$10/t

Ethanol made using Geothermal Steam to be Ethanol made using Geothermal Steam to be cheaper by 4.5 NZc/Lcheaper by 4.5 NZc/L

Ethanol from Sugar CropsEthanol from Sugar Crops Sugar Cane and Sugar Beet widely used Ethanol feedstocksSugar Cane and Sugar Beet widely used Ethanol feedstocks

Brazil produced 4.5b Gallons of Ethanol in 2006Brazil produced 4.5b Gallons of Ethanol in 2006

Contains Sucrose which can be directly fermented into EthanolContains Sucrose which can be directly fermented into Ethanol

Hence, processes are relatively simpler and more cost effectiveHence, processes are relatively simpler and more cost effective

Sugar Cane is of particular interestSugar Cane is of particular interest Has high ethanol yield: 7750 L/Ha (Corn: 2750 L/Ha)Has high ethanol yield: 7750 L/Ha (Corn: 2750 L/Ha) Shorter fermentation period of 6-10 hours (Corn: 48 - 72 hrs)Shorter fermentation period of 6-10 hours (Corn: 48 - 72 hrs)

Ethanol from Waste Ethanol from Waste Products – Cellulosic WasteProducts – Cellulosic Waste

Cellulosic materials – most abundant and potentially Cellulosic materials – most abundant and potentially cheap feedstock for ethanol productioncheap feedstock for ethanol production

Includes wastes from agriculture, forest and municipal Includes wastes from agriculture, forest and municipal solid waste.solid waste.

Potential to exploit 290,000 t.p.a of landfilled paper Potential to exploit 290,000 t.p.a of landfilled paper waste and 430,000 t.p.a. of cereal straw.waste and 430,000 t.p.a. of cereal straw.

Manufacturing cost estimated at NZ$0.7-NZ$1.30/ L Manufacturing cost estimated at NZ$0.7-NZ$1.30/ L EtOH EtOH

Technology currently exists on Lab. scale onlyTechnology currently exists on Lab. scale only

Ethanol from Potato Processing WasteEthanol from Potato Processing Waste

500,000 t.p.a grown on 20% of total arable farm land500,000 t.p.a grown on 20% of total arable farm land Solid potato waste accounts for about 20% of potato Solid potato waste accounts for about 20% of potato

cropcrop Potatoes have a high fermentable carbohydrate Potatoes have a high fermentable carbohydrate

content of 20% w/wcontent of 20% w/w Starch from 150,000 tonne potato waste can be Starch from 150,000 tonne potato waste can be

potentially converted to 1.5 MML of ethanolpotentially converted to 1.5 MML of ethanol Estimated production cost: NZ$1.4-1.5 / L EtOHEstimated production cost: NZ$1.4-1.5 / L EtOH Co-processing with other feedstock likely to reduce Co-processing with other feedstock likely to reduce

these costs by 50c to NZ$0.9-1.0 / L EtOHthese costs by 50c to NZ$0.9-1.0 / L EtOH

Ethanol from Fruit Crop Ethanol from Fruit Crop Waste – Kiwi fruitWaste – Kiwi fruit

Kiwi fruit has very high content of Starch, Kiwi fruit has very high content of Starch, Fructose and Sucrose.Fructose and Sucrose.

Fermentable sugar content estimated as 8%Fermentable sugar content estimated as 8%(w/w).(w/w).

Average ethanol yield of 44 L EtOH/t kiwi fruit.Average ethanol yield of 44 L EtOH/t kiwi fruit. Cost of making ethanol from kiwi fruit, in an Cost of making ethanol from kiwi fruit, in an

already existing ethanol plant is estimated at already existing ethanol plant is estimated at NZ$0.7-0.8/ L EtOHNZ$0.7-0.8/ L EtOH

ConclusionsConclusions

NZ grows several agricultural products that NZ grows several agricultural products that have the potential to be converted into bio have the potential to be converted into bio ethanolethanol

Sugars crops such as Sugar cane are easier to Sugars crops such as Sugar cane are easier to process than Starch crops such as Maize.process than Starch crops such as Maize.

Ethanol can be produced in NZ at the cost of Ethanol can be produced in NZ at the cost of NZ$0.7-1.0/L EtOH depending upon the NZ$0.7-1.0/L EtOH depending upon the feedstock used.feedstock used.

AcknowledgementAcknowledgement

Foundation of Research Science and Foundation of Research Science and Technology (FRST) for their generous Technology (FRST) for their generous financial supportfinancial support

Derek Turnbull, Steve HolmesDerek Turnbull, Steve Holmes

Tamaki Controls Ltd.Tamaki Controls Ltd.

Project MentorsProject Mentors