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Slide 1 :
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ONION DEHYDRATION WITH GEOTHERMAL ENERGY IN THE USA John W. Lund
Andrew Chiasson, Toni Boyd
Geo-Heat Center
Oregon Institute of Technology
Klamath Falls, OR, USA |
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PROCESSING Creoloe, Southport Globe and Hybrid Southport types used
White in color and process a higher solid content which yields a more flavorful and pungent onion
Continuous belt conveyor used
Proctor & Schwartz dehydrator single line
Special silica gel – Bryair desiccation often used for the final drying
$1,500,000/yr in fuel used (180 days)
Geothermal saves 116 million cubic feet of NG |
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Basic dehydration operation |
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PROCESSING 2 Dehydration – basic steps
Harvesting
Transporting
Curing - 100oF heated air used – ease of peeling and processing – 48 to 72 hours
Washing and chlorinated to reduce bacteria
Slicing
Dehydration – in 3 to 4 stages – high air volumes
Milling (powdered, granulated, ground, minced, chopped or sliced)
Packaging |
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AGRICULTURAL DRYING 1 Two large geothermal onion and garlic dehydrators are located in NW Nevada
These units can each process 5 - 7 tons of wet onions/hr – drying them from 83% to 4% moisture (output = 0.9 – 1.2 tons/hr dried product)
0.15 therms/lb used = 500 million Btu/day or 76 billion Btu/yr (22 GWh) (150 days period)
Product used in soups, baked goods, salt, & seasoning as powders to slices |
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AGRICULTURAL DRYING 2 Single-line, continuous-belt dryer use
12.5 ft wide
190 to 212 ft. long
3 to 4 sections (A to D) –210 to 120oF
Processing 5 to 7 tons/hr of wet onions
Using 86,500 ft3/hr of air
26 million Btu/hr
Onions 2 inches to 6 feet deep
Bryair desiccation unit required in final stage
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AGRICULTURAL DRYING 3 Brady’s Hot Spring plant – first in U.S. - 1978
270oF geothermal fluid
Only has 3 stages (A thru C)
6-months operation season - 65 employees
25,000 tons of wet onions are processed during season – producing 5,000 tons of dry product
190-ft. long dryer by 12.5 ft. wide
Uses 190 to 120oF air in various stages
Has also processed celery and carrots to extend season
Product trucked from S. California to S. Oregon (300 to 600 miles)
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AGRICULTURAL DRYING 4 Empire Foods plant – constructed 1994
Capacity
37 tons/day onions; 42.5 tons/day garlic
7 tons/yr (60% onions and 40% garlic)
900 gpm of geothermal fluid @ 266oF
45 million Btu/hr – discharge at 160oF
Cold storage warehouse allows year-round operation – 2nd line being considered
Geothermal energy also used for four ORMAT 1.5-MWe binary units – net output 3.6 MWe
Now shut down due to garlic imports from China |
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Empire 6.0 MWe binary plants (3.6 MWe net) |
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CONCLUSIONS 1 A survey in the U.S. found that of 108 industrial processes surveyed (representing 80% of U.S. industrial energy usage), 97% of all processes required heat input in the form of steam at 250oF or higher.
An examination of geothermal wells in 8 western U.S. states reveals that 99% are 250oF or less.
High load factor important (0.44 to 0.68 in 2000)
Wells above 250oF would normally be used for electric power generation, however ----
* source: K. Rafferty, GHC Bulletin Vol. 24, No. 3 (Sept., 2003) |
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CONCLUSION 2 Consider: Power plant vs dehydration plant
Assumptions
300oF resource
20 MW net binary power plant
US$0.07 per kWh power sales price
10-month dehydration operation
15,000 tons annual production (2 lines)
US$1.00/lb dried product wholesale price
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CONCLUSIONS 3 Power plant vs dehydration plant
Power Dehydration
plant plant
Capital Expenditure $50 mill. $15 mill.
Gross Revenue $11 mill. $30 mill.
Resource require. 12,000 gpm 1,200 gpm
Employees 15 75
*source: D. Mendive, Geothermal Development Assoc., Reno, NV |
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Slide 20 :
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RESOURCE EVALUATION Initial search of data base
Ontario, Lancaster, Vale, Nyssa , Harper and Adrain
42 by 36 mile area
9 springs
270 wells identified
68 to 239oF – high temp. at Vale
Most below 200oF
One “dry well” – 10,052 ft at 334oF - Ontario |
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PROPOSED SCOPE OF WORK Determine source and market of product
Estimate size of development
Determine temperature and flow rate needed
Review literature and determine resource available to meet requirements
Recommend site(s) for resource (well)
Perform economic analysis
Make recommendation(s)
Write final report |
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