Small Scale NZ Biofuel Techno-Economic Investigation

1. Small Scale NZ Biofuel Techno-Economic Investigation VISHESH ACHARYA MASTER OF ENGINEERING DR. BRENT YOUNG CHEMICAL AND MATERIALS ENGINEERING UNIVERSITY OF AUCKLAND

2. OVERVIEW • Introduction to Bio Ethanol • Benefits of Blending Ethanol with Petrol • Bio Ethanol Manufacturing Process • Classification of feedstock • Potential of various Starch, Sugar and Cellulosic materials as Feedstock in NZ • Conclusions

3. What is Bio Ethanol? • Alcohol based liquid fuel made from agricultural bio mass • Produced by fermenting sugar from Energy crops • EU, USA and Brazil mandate a minimum ethanol blend. • NZ govt mandates selling a minimum of 0.25% of all fuel sold to be that of Bio fuels, starting 2008

4. Benefits of Blending Ethanol with Petrol • Contains 35 mole percent O2 • Acts as an oxygenate – facilitates combustion to a greater extent • Increases energy efficiency by 1%

5. Manufacturing Process ENZYMES Feedstock HYDROLYSIS 50% EtOH ENZYMES 95% EtOH YEAST AZEOPTROPIC DEHYDRATOR 10% EtOH FERMENTATION RECTIFIER BEER STRIPPER 99.6% FUEL GRADE ETHANOL WATER SOLIDS

6. Classification of Feedstock • Classified 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.

7. SACHHARINE Fruits Molasses STARCH GrainsPotatoes CELLULOSE DRY Green PRE TREATMENT MILLING SHREDDING MASHING MASHING DILUTION DILUTION DILUTION LIQUEFACTION HYDROLYSIS HYDROLYSIS FERMENTATION DISTILLATION DEHYDRATION DENATURING STORAGE

8. Starch Crops • Maize, Wheat, Barley and Milo (Sorghum) are the most extensively used Starch based feedstock • Maize is the most widely used feedstock • Current annual production of Maize based ethanol is ~20 Billion L

9. Ethanol from Maize • Ethanol from Maize is produced by 2 methods: • 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

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

11. Ethanol from Maize 2. Wet Milling • Gluten Feed, Starch, Corn oil, Corn Germ and Corn Syrup Liquid – Primary products. • Starch is further hydrolysed and fermented to Ethanol • Typical Yield: 440 L EtOH / T Dry Maize • Yield lower than Dry milling as some starch is lost in co-products. • Process more complex than Dry milling • Hence, requires higher capital investment

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

13. Ethanol from NZ Maize • 150,000 tonne Maize grown on 13,000 Ha. of land • NZ Maize yield: 12.5 t/Ha (U.S. Maize yield: 8 t/Ha) • Energy input for un-irrigated arable Maize farming in NZ : 1683 MJ / t Maize • Avg. US Maize farming input : 2425 MJ / t Maize

14. Cost – Ethanol from NZ Maize • Potential Yield: 397 L EtOH / t Maize • Dry Mill Process, 95 ML/yr • 90.3 NZc/L EtOH • Maize sourced from within 100km @ NZ$10/t • Wet Mill Process, 95 ML/yr • 76.6 NZc/L EtOH • Maize sourced from within 100km @ NZ$10/t • Ethanol made using Geothermal Steam to be cheaper by 4.5 NZc/L

15. Ethanol from Sugar Crops • Sugar Cane and Sugar Beet widely used Ethanol feedstocks • Brazil produced 4.5b Gallons of Ethanol in 2006 • Contains Sucrose which can be directly fermented into Ethanol • Hence, processes are relatively simpler and more cost effective • Sugar Cane is of particular interest • Has high ethanol yield: 7750 L/Ha (Corn: 2750 L/Ha) • Shorter fermentation period of 6-10 hours (Corn: 48 - 72 hrs)

16. Ethanol from Waste Products – Cellulosic Waste • Cellulosic materials – most abundant and potentially cheap feedstock for ethanol production • Includes wastes from agriculture, forest and municipal solid waste. • Potential to exploit 290,000 t.p.a of landfilled paper waste and 430,000 t.p.a. of cereal straw. • Manufacturing cost estimated at NZ$0.7-NZ$1.30/ L EtOH • Technology currently exists on Lab. scale only

17. Ethanol from Potato Processing Waste • 500,000 t.p.a grown on 20% of total arable farm land • Solid potato waste accounts for about 20% of potato crop • Potatoes have a high fermentable carbohydrate content of 20% w/w • Starch from 150,000 tonne potato waste can be potentially converted to 1.5 MML of ethanol • Estimated production cost: NZ$1.4-1.5 / L EtOH • Co-processing with other feedstock likely to reduce these costs by 50c to NZ$0.9-1.0 / L EtOH

18. Ethanol from Fruit Crop Waste – Kiwi fruit • Kiwi fruit has very high content of Starch, Fructose and Sucrose. • Fermentable sugar content estimated as 8%(w/w). • Average ethanol yield of 44 L EtOH/t kiwi fruit. • Cost of making ethanol from kiwi fruit, in an already existing ethanol plant is estimated at NZ$0.7-0.8/ L EtOH

19. Conclusions • NZ grows several agricultural products that have the potential to be converted into bio ethanol • Sugars crops such as Sugar cane are easier to process than Starch crops such as Maize. • Ethanol can be produced in NZ at the cost of NZ$0.7-1.0/L EtOH depending upon the feedstock used.

20. Acknowledgement • Foundation of Research Science and Technology (FRST) for their generous financial support • Derek Turnbull, Steve Holmes Tamaki Controls Ltd. Project Mentors