• TABLE OF CONTENTS
HIDE
 Copyright
 Title Page
 Energy requirements freezing orange...
 Use of the heat content chart
 Energy savings by tank farm storage...
 Glossary
 Literature cited






Group Title: Florida Cooperative Extension Service circular 497
Title: Energy conservation in citrus processing
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00072011/00001
 Material Information
Title: Energy conservation in citrus processing freezing orange concentrate
Series Title: Circular Florida Cooperative Extension Service
Physical Description: 7 p. : ill. ; 23 cm.
Language: English
Creator: Matthews, R. F
Chen, Chin Shu
Publisher: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville
Publication Date: 1981?
 Subjects
Subject: Citrus fruit industry -- Energy consumption   ( lcsh )
Citrus fruit industry -- Energy conservation   ( lcsh )
Frozen concentrated orange juice   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 8
Statement of Responsibility: R.F. Matthews and Chin Shu Chen.
General Note: Cover title.
Funding: Circular (Florida Cooperative Extension Service) ;
 Record Information
Bibliographic ID: UF00072011
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: oclc - 08852132

Table of Contents
    Copyright
        Copyright
    Title Page
        Page 1
    Energy requirements freezing orange juice and concentrate
        Page 2
    Use of the heat content chart
        Page 3
        Page 4
        Page 5
    Energy savings by tank farm storage of concentrate
        Page 6
        Page 7
    Glossary
        Page 8
    Literature cited
        Page 8
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida





Circ. 497


Energy Conservation in Citrus Processing
-Freezing Orange Concentrate-


R. F. Matthews and Chin Shu Chen


Florida Cooperative Extension Service
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
John T. Woeste, Dean for Extension






Energy Conservation in Citrus Processing
Freezing Orange Concentrate
R. F. Matthews and Chin Shu Chen*

A 1979-80 survey (1) of the citrus processing industry estimated
the total annual energy use to be approximately 12 trillion Btu, or
the equivalent of 2 million barrels of oil. This equates to one barrel
of oil for every 100 boxes of fruit processed. Boilers used 4.3 trillion
Btu to generate approximately 3 billion lbs of steam, primarily used
to evaporate 8.7 billion lbs of water. Feed mills consumed approx-
imately 6.5 trillion Btu in the production of 870,000 tons of cattle
feed. Refrigeration accounted for an additional 0.4 trillion Btu's.
The four areas accounted for 76% of the total plant energy cost:
Energy Cost
% Total Plant
Feed Mill Dryers 40
Evaporation 21
Refrigeration 10
Boilers 5
76
Florida citrus processors have refrigerated storage facilities for
approximately 60 million gallons of frozen concentrated orange
juice. This includes freezer rooms for drum storage and tank farms.
The drum storage facilities for concentrate are maintained at -10
to 0F to prevent loss of quality in storage. At higher storage
temperatures browning of the concentrate and flavor degradation
occur.
In tank farm storage of concentrate, experience has shown that
+150 to +20F storage is satisfactory to prevent browning and re-
tain desirable flavor. The ability to satisfactorily store orange con-
centrate in tank storage at higher temperatures than used for drum
storage is attributed to the exclusion of oxygen. Air is excluded in
tank storage by an inert gas purge system using either nitrogen or
carbon dioxide.
Energy Requirements Freezing Orange Juice and Concentrate
It is necessary in many operations to determine the energy input
required to lower the temperature in the production of frozen con-
centrated orange juice.
Freezing citrus juice concentrate differs radically from the freez-
ing of water. When freezing water, the temperature drops at a con-
stant rate until the freezing point temperature (32F) is reached
(Fig. 1). The temperature remains at 320F until all the water is

*R. F. Matthews is a Professor in the Food Science and Human Nutrition De-
partment in Gainesville. Chin Shu Chen is an Adjunct Professor of Food En-
gineering at the Lake Alfred Agricultural Research and Education Center,
cooperative with the Florida Department of Citrus.






frozen. The temperature of the frozen water then continues to drop
below 320F at a constant rate. As the temperature of frozen con-
centrate is reduced there is no distinct break in the freezing curve
(Fig. 1) and only a portion of the water is frozen.
The heat content chart (Fig. 2) provides much useful information
on freezing juice and concentrates with a soluble solids content
ranging from 0 to 700 Brix. The initial freezing point, the percent
water frozen in the concentrate at different temperatures and the
heat content of concentrates at different temperatures may be
determined from this chart.
It is estimated (Fig. 2) that in a 400 Brix citrus concentrate held
at 150F, 75% of the water remains unfrozen and at 0F, approx-
imately -140 of the water is unfrozen. The initial freezing point of a
65 Brix concentrate is approximately -4 F.

Use of the Heat Content Chart
The information that can be obtained from the heat content chart
(Fig. 2) is illustrated in Fig. 3. Note that the crossing of any two
property lines establishes a point from which all other values can be

80i -


'0 20 40 60 80 100 120 140 160 180 200 220
HEAT CONTENT (BTU / b) h
Fig. 1. Heat content of orange juice and concentrate (calculated based on Riedel's Mol-
lier Chart).

















S140

S-
CO

120 C\/
I00



I-











0 10 20 30 40 50 60 70
o 80- 0 60OF

X 400






Fig. 2. Heat Content Chart







obtained., From Fig. 3, read point "A"- Brix, "B"- % water
frozen and temperature, "C"- initial freezing point, and "D"- heat
content. For example, to find the properties for 40 Brix concen-
0%0






rate at 12F, first locate 40 Brix (point "A") on the Brix line in
SOLIDS CONTENT (%) or OBRIX --




Fig. 2, then draw a vertical line from "A" to intersect the 12
obtained., From Fig. 3, read point "A"- 'Brix, "B"- % water
frozen and temperature, "C"- initial freezing point, and "D"- heat
content. For example, to find the properties for 40' Brix concen-
trate at 12'F, first locate 40' Brix (point "A") on the Brix line in
Fig. 2, then draw a vertical line from "A" to intersect the 120F
temperature line at point "B". At point "B" the % water frozen
(35%) may be read. Extend line AB to intersect the 0% water frozen
line at point "C". The initial freezing temperature (19.50F) is read at
point "C". Draw line BD (parallel to Brix line) to intersect the heat
content line at point "D". The heat content of the 400 Brix concen-
trate, at 12F, is read at point "D" and is 68 Btu/lb.
The heat content of a substance is the summation of the sensible
heat and the latent heat.






In determining the energy required to freeze orange concentrate it
is necessary to use the heat content value. Table 1 lists heat content
values of orange concentrate (0-650 Brix).
A number of sample problems are presented to demonstrate how
to determine the energy required to freeze orange concentrate using
the heat content values in Table 1. Different solids levels for the
concentrate and different final temperatures are used in the prob-
lems.
Sample problem 1
A 55 gallon drum of concentrated orange juice (550 lbs) is to be
frozen to a temperature of -10 F. The initial temperature of the con-
centrate is 500F, and solids content is 600 Brix.


















I C
z
Z




"I-





A

SOLIDS CONTENT(%) OR OBRIX

Fig. 3. Illustration of how to use the heat content chart (Fig. 2) to obtain (1) the %
water frozen (2) the initial freezing point and (3) the heat content (Btu/Ib).






How much heat must be removed?
Solution: the heat to be removed
H= W(h, h)
Where H = total heat to be removed, Btu
W = weight of the concentrate in pounds
h2= heat content at final temp., Btu/lb
h,= heat content at initial temp., Btu/lb
Obtain the heat content values from Table 1.
h, at 50F = 90
h2 at -100F = 34
H= W(h2 h)
H = 550 x (34-90) = 550 (-56) = -30,800 Btu
The negative value indicates that the 30,800 Btu must be re-
moved from the concentrate during the freezing process.
Sample problem 2
Concentrated orange juice (550 lbs) is to be frozen to a tem-
perature of 200F. The initial temperature of the concentrate is 50F
and the solids content is 600 Brix.
How much heat must be removed?
Solution: Obtain the heat content values from Table 1.
H = W (h, h,)
H = 550 (70-90) = 550 (-20) = -11,000 Btu
Sample problem 3
A 55 gallon drum of concentrated orange juice (550 lbs) is to be
heated from -10F to 30F. The solids content is 600 Brix.
How much heat must be added?
Solution: Obtain heat content values from Table 1.
H = W (h2 hJ)
H = 550 (77-34) = 550 (43) = 23,650 Btu
Sample problem 4
Concentrated orange juice (550 lbs) is to be heated from 200F to
300F. The solids content is 600 Brix.
How much heat must be added?
Solution: Obtain heat content values from Table 1.
H = W (h, hi)
H = 550 (77-70) = 550 (7) = 3,850 Btu
Energy Savings by Tank Farm Storage of Concentrate
Sample problem 1 illustrates the energy required to freeze a 55
gallon drum (550 lbs) of 600 Brix orange concentrate to -10F for
storage. Sample problem 3 illustrates the energy required to warm
the concentrate to 30F for retail packaging.







The energy (Btu) used in the process is:
Sample problem 1 (50oF -10oF) 30,800 Btu/550 lbs
Sample problem 3 (-10F 300F) 23,650
54,450 Btu/550 lbs
Sample problem 2 illustrates the energy required to freeze 550 lbs of
600 Brix orange concentrate to 20F for tank farm storage. Sample
problem 4 illustrates the energy required to warm the concentrate
to 30F for retail packaging.
Sample problem 2 (50F 200F) 11,000 Btu/550 lbs
Sample problem 4 (20 F 30F) 3,850
14,850 Btu/550 lbs
The difference in energy between tank farm storage (200F) and 55
gallon drum storage (-10F) is: 54,450 Btu
-14,850 Btu
39,600 Btu/500 lbs concentrate
This represents a major energy conservation technique which
results in significant energy and dollar savings.
Sample problem 5
Orange juice (550 lbs) is to be frozen to a temperature of 200F.
The initial temperature of the juice is 50 F and the solids content is
120 Brix.
How much heat must be removed?
Solution: Obtain heat content values from Table 1.
H= W(h2 h)
H = 550 (49-172) = 550 (-123) = -67,650 Btu
In sample problem 2, a 60 Brix orange concentrate was frozen to
200F. The Btu required for the concentrate was 11,000 Btu. It takes
six times 67,650 6.15)the energy to reduce the temperature of
11,000
the 12 Brix juice to 200F as it does to reduce the 600 Brix concen-
trate to 200F.


Table 1. Heat content of


Brix
0
12
42
45
50
55
60
65


orange concentrate (Btullb)


Temperature OF
-40 -10 0 10 20 31


0 40 50 60







Glossary
Standard ton of refrigeration defined as the transfer of 200 Btu
per minute, 12,000 Btu per hour, or 288,000 Btu per 24 hours.
This is equal to the Btu needed to freeze one ton (2,000 lbs) of
water in 24 hours.
Btu (British thermal unit)- the quantity of heat required to raise
the temperature of one pound of water one degree Fahrenheit at,
or near, its point of maximum density (39.10F). The Btu is
equivalent to 0.252 kilogram-calorie.
Specific heat heat capacity of a substance compared to that of
water. Specific heat is a dimensionless ratio that is numerically
equal to the heat capacity of the substance.
Sensible heat heat input that causes a change in the temperature
of the substance (perceptible to the human senses).
Latent heat heat that results in a change of state of a substance
without a change in temperature.
Heat of fusion latent heat of a substance to change from the solid
state to the liquid state. For pure water at o0C the heat of fusion
is 144 Btu/lb.

Literature Cited
Holladay, K. L., R. M. Radanof, and M. J. Noll. 1980. Energy
Audits in the Citrus Industry. pp 59-77, in Proceedings of the
20th Annual Short Course for the Food Industry, University
of Florida.
Chen, C. S. 1979. Specific heat of the citrus juice and concentrate.
Proc. Fla. State Hort. Soc. 92:154-156.
Riedel, L. 1951. The refrigerating effect required to freeze fruits and
vegetables. Refrigerating Engineer 59:(7):670-673.




This publication was printed at a cost of $477.48, or 24 cents
per copy, to inform Florida citrus processors about energy
saving. 8-2M-81



COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLOR-
IDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES,
K. R. Tefertller, director, In cooperation with the United States IAS
Department of Agriculture, publishes this information to further the
purpose of the May 8 and June 30, 1914 Acts of Congress; and is
authorized to provide research, educational information and other
services only to individuals and institutions that function without regard to race, color,
sex or national origin. Single copies of Extension publications (excluding 4 -H and Youth
publications) are available free to Florida residents from County Extension Offices.
Information on bulk rates or copies for out-of-state purchasers Is available from C. M.
Hinton, Publications Distribution Center, IFAS Building 664, University of Florida,
Galnesvllle, Florida 32611. Before publicizing this publication, editors should contact
this address to determine availability.







Glossary
Standard ton of refrigeration defined as the transfer of 200 Btu
per minute, 12,000 Btu per hour, or 288,000 Btu per 24 hours.
This is equal to the Btu needed to freeze one ton (2,000 lbs) of
water in 24 hours.
Btu (British thermal unit)- the quantity of heat required to raise
the temperature of one pound of water one degree Fahrenheit at,
or near, its point of maximum density (39.10F). The Btu is
equivalent to 0.252 kilogram-calorie.
Specific heat heat capacity of a substance compared to that of
water. Specific heat is a dimensionless ratio that is numerically
equal to the heat capacity of the substance.
Sensible heat heat input that causes a change in the temperature
of the substance (perceptible to the human senses).
Latent heat heat that results in a change of state of a substance
without a change in temperature.
Heat of fusion latent heat of a substance to change from the solid
state to the liquid state. For pure water at o0C the heat of fusion
is 144 Btu/lb.

Literature Cited
Holladay, K. L., R. M. Radanof, and M. J. Noll. 1980. Energy
Audits in the Citrus Industry. pp 59-77, in Proceedings of the
20th Annual Short Course for the Food Industry, University
of Florida.
Chen, C. S. 1979. Specific heat of the citrus juice and concentrate.
Proc. Fla. State Hort. Soc. 92:154-156.
Riedel, L. 1951. The refrigerating effect required to freeze fruits and
vegetables. Refrigerating Engineer 59:(7):670-673.




This publication was printed at a cost of $477.48, or 24 cents
per copy, to inform Florida citrus processors about energy
saving. 8-2M-81



COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLOR-
IDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES,
K. R. Tefertller, director, In cooperation with the United States IAS
Department of Agriculture, publishes this information to further the
purpose of the May 8 and June 30, 1914 Acts of Congress; and is
authorized to provide research, educational information and other
services only to individuals and institutions that function without regard to race, color,
sex or national origin. Single copies of Extension publications (excluding 4 -H and Youth
publications) are available free to Florida residents from County Extension Offices.
Information on bulk rates or copies for out-of-state purchasers Is available from C. M.
Hinton, Publications Distribution Center, IFAS Building 664, University of Florida,
Galnesvllle, Florida 32611. Before publicizing this publication, editors should contact
this address to determine availability.




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs