Pacific Gas and Electric Company
Emerging Technologies Program
Application Assessment Report #0706
Performance Study of a Mechanical Vapor
Recompression (MVR) Evaporation System
Issued: December 2007 Project Manager: Ryan Matley Pacific Gas and Electric Company Prepared By: Heschong Mahone Group 11626 Fair Oaks Blvd. #302 Fair Oaks, CA 95628
Legal Notice This report was prepared by Pacific Gas and Electric Company for exclusive use by its employees and agents. Neither Pacific Gas and Electric Company nor any of its employees and agents: (1) makes any written or oral warranty, expressed or implied, including, but not
limited to those concerning merchantability or fitness for a particular purpose;
(2) assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, process, method, or policy contained herein; or
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© Copyright, 2008, Pacific Gas and Electric Company. All rights reserved.
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TABLE OF CONTENTS 1. EXECUTIVE SUMMARY ...........................................................................................3
2. INTRODUCTION .........................................................................................................5
2.1 Background........................................................................................................5
2.2 Project Objectives ..............................................................................................5
2.3 Tomato Evaporation Technologies ....................................................................5
2.4 Host Site MVR and triple effect evaporation systems.......................................7
3. PERFORMANCE MONITORING AND EVALUATION...........................................9
3.1 Performance Monitoring....................................................................................9
3.2 Performance Evaluation.....................................................................................9
4. RESULTS AND DISCUSSION..................................................................................12
5. MVR PERFORMANCE MODEL...............................................................................18
6. CONCLUSIONS..........................................................................................................20
7. APPENDIX..................................................................................................................21
7.1 Performance Monitoring Data .........................................................................21
7.2 Screen Snapshots of the MVR Performance Model ........................................27
7.3 Reference .........................................................................................................30
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TABLE OF FIGURES Figure 1 Summary of MVR and triple effect energy consumption.......................................3
Figure 2 Illustration of evaporation process .......................................................................6
Figure 3 Schematics of a triple effect evaporation system ..................................................6
Figure 4 Schematics of a MVR evaporation system ............................................................7
Figure 5 Picture of the host site MVR system......................................................................8
Figure 6 Picture of the host site triple effect system............................................................8
Figure 7 Mass flow around a MVR evaporator.................................................................16
Figure 8 Energy flow around a MVR evaporator..............................................................16
Figure 9 Mass flow around a triple effect evaporator.......................................................17
Figure 10 Energy flow around a MVR evaporator............................................................17
Figure 11 Process flow diagram of the triple effect model ...............................................18
Figure 12 Process flow diagram of the MVR model..........................................................19
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1. EXECUTIVE SUMMARY
PG&E Emerging Technologies Department sponsored this study to evaluate the energy savings potential of a mechanical vapor recompression (MVR) tomato evaporator, as compared to a triple effect evaporator.
The MVR system has three stages of evaporation, all operated at about 180 oF. On average, the tomato paste BRIX number was increased from 7.5 to 9.8 for cold break and from 7.3 to 9.3 for hot break. BRIX number is defined as the percentage of solid contents by weight. The energy input to the MVR system was from a compressor that was driven by a steam turbine. For each pound of water evaporated, the average energy consumed by the steam turbine was 50.2 Btu for cold break and 48.5 Btu for hot break.
In the triple effect system, the three evaporators were in operation at 113 oF, 153 oF, and 183 oF. Tomato paste concentration was increased from 10.3 to 18.4 BRIX for cold break and from 9.7 to 15.3 for hot break. Figure 1 provides a summary of energy consumption for both the MVR and triple effect systems. For each pound of water evaporation, the average steam input energy was 468 Btu for cold break and 441 Btu for hot break. Therefore, the MVR system required only 11% of the steam energy consumed by a triple effect system for evaporating the same amount of water, excluding other auxiliary power consumptions.
0
100
200
300
400
500
600
Hot Break Cold Break Hot Break Cold Break
MVR 3-effect
Btu
/lb o
f wat
er e
vapo
rate
d
CondenserEvaporation
Figure 1 Summary of MVR and triple effect energy consumption
MVR technologies are limited to evaporating tomato with low solids concentrations. Tomato paste with higher solids concentrations has lower thermal conductivity. It requires higher input steam temperature to achieve effective evaporation. Or, in other words, the evaporated water vapor needs to be compressed to higher pressure levels. Compression ratio for typical MVR compressors is limited to 1.6, which determines the maximum tomato paste output concentration. It should also be noted that the MVR technology still has large energy savings potential even with this limitation on tomato concentration. This is because concentrating tomato from 5.5 BRIX (raw tomato
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concentration) to 10 BRIX (MVR limitation) represents roughly 50% of the total water removal for reaching final product concentration of 31% BRIX.
Steam condensate left evaporators at high evaporation temperatures of up to 183 oF. Compared to the city supply water temperature at 70 oF, the associated thermal energy was 113 Btu per pound of condensate. Also, the water quality was very good, since it was largely from water in tomatoes. The most practical approach for recovering the associated thermal energy is to use it as boiler feed water. At the host site, the steam condensate was not fully recovered for either the MVR or triple effect systems, due to the fact that condensate production was more than total steam demand.
Energy consumption related to recirculation pumps was similar for both systems and was estimated to be between 24 and 31 Btu per pound of water evaporation.
The study also developed energy performance models for the MVR and triple effect systems. An EXCEL spreadsheet tool was built to estimate MVR energy savings based user inputs of key MVR and triple effect parameters.
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2. INTRODUCTION
2.1 Background The PG&E Emerging Technology Department has identified the MVR system as a promising energy efficient technology for food evaporation processes and sponsored this study to investigate the performance of a MVR system at a tomato processing plant.
California produces more than ten million ton of tomato every year, representing 95% of the total US production. Tomato concentration through evaporation is an important step in tomato processing. There are 15 major tomato processors with 18 major processing facilities in California, providing more than 1.7 million lb/hr processing capacity. This large tomato processing industry consumes substantial amount of energy every year. For example, the 2007 industry-wide tomato production was 12 million tons. With typical triple effect evaporation systems, which take about 450 Btu for evaporating one pound of water, the annual industry-wide fuel energy consumption would be about 105 million therms. Application of energy efficient technologies in this area could lead to significant energy savings.
2.2 Project Objectives The objective of this field performance monitoring study is to assess the energy consumption characteristics of a MVR system and a triple effort system for tomato processing. The study will also develop a model for estimating energy savings of MVR systems, as compared to triple effect systems. This model is validated by the field performance monitoring results.
2.3 Tomato Evaporation Technologies Figure 2 through Figure 4 illustrate several evaporation systems. In general, an evaporator consists of a calandria, where tomato paste is heated by steam, and a separator, where water vapor is separated from the tomato paste. Evaporation processes keep the tomato paste at a constant temperature, determined by the tomato paste pressure. Similarly, steam stays at a constant temperature as it is cooled by the tomato paste and condenses into liquid water. As a result, the temperature difference between steam and tomato paste is held constant through the evaporation process. The industry often used the measure of steam economy to gage evaporator efficiency, which is defined as the ratio of water evaporation to steam input by weight.
In a single effect evaporation system (Figure 2), water vapor from the tomato paste is not used for further evaporation. The latent heat carried by the vapor is wasted if it is condensed through a condenser. Under typical evaporation conditions, this system takes about 1000 Btu to evaporate one pound of water, assuming the steam economy is 100%.
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Figure 2 Illustration of evaporation process
A multiple effect evaporation system has more than one evaporator. As shown in Figure 3, water vapor from one effect is used to drive the next stage of evaporation, at a lower temperature. The result is that the latent heat from the steam input is used several times and the total steam consumption is greatly reduced. For example, a triple effect system would ideally use 1/3 of the steam required by a single effect system. Since each succeeding effect has to be operated at lower pressures and temperatures, the number of effects that can be achieved is limited by the initial tomato temperature.
Figure 3 Schematics of a triple effect evaporation system
2nd Effect 3rd Effect
17% 1st Effect
Further evaporation
12.5% 9.9%
Steam Condensate
Steam Input
35,300 lb/hr
Condenser
Calandria
Separator
Recirculating Pump
Condensate
Tomato Paste Input
Steam Input
Vapor Output
Tomato Input
191,800 lb/hr
7.3%
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Thermal vapor recompression (TVR) uses high-pressure steam to compress water vapor to recycle latent heat. Due to the inherent thermodynamic effect, not all vapor is recompressed and steam input is still required. The advantage of a TVR system is its simplicity, therefore, lower cost. A TVR system can achieve similar energy efficiency as a multiple effect system, but with a smaller number of effects.
Figure 4 Schematics of a MVR evaporation system
In the MVR system shown in Figure 4, water vapor from tomato paste is compressed by a compressor or fan to a higher a pressure and temperature so that it can be used by the same evaporator. No additional steam is required except during the process startup. Effectively, latent heat from the initial steam is recycled as long as the process is not stopped. Since the compression power is less than the latent energy carried by the water vapor, energy consumption per pound of water evaporation is much smaller than multiple effect systems.
2.4 Host Site MVR and triple effect evaporation systems The host plant had two independent tomato processing systems. One of them utilized MVR technology and the other utilized triple effect technology. Figure 5 shows a picture of the MVR system and Figure 4 provides the process diagram. Tomato paste was concentrated from 7.3% to 10% through three stages of evaporation, all at 180 oF. Water vapor from all three stages was compressed by a steam turbine driven by a compressor. The compressor discharge pressure was about 12.2 psia, which corresponded to a saturation temperature of 203 oF.
Figure 6 shows a picture of the triple effect system and Figure 3 provides the process diagram. Tomato paste was concentrated from 7.3% to 17%. By the third stage, evaporated water vapor was no longer used and was sent to a condenser.
MVR 3 MVR 2 Tomato Input
195,069 lb/hr
~180 ºF
7.3%
MVR 1
Compressor
Further evaporation
8.6% 9.1% 10.0%
Vapor
51,515 lb/hr
Steam Turbine
280 psi Steam
Steam Condensate
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Figure 5 Picture of the host site MVR system
Figure 6 Picture of the host site triple effect system
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3. PERFORMANCE MONITORING AND EVALUATION
3.1 Performance Monitoring The primary energy input for the MVR system was steam, which was used to drive the compressor and three recirculation pumps. The triple effect system consumed steam for evaporation and for driving three recirculation pumps. It also consumed electric power for the corresponding condenser sub-system. The host site did not have any steam flow measurement. It was also not possible to install any inline flow meters during the monitoring period, which occurred during the tomato harvesting season and thus the host site was operating continuously. The project team did not believe that the strap-on ultra-sonic type flow meters could provide reliable steam flow measurements. The host site did have flow meters for all steam condensate flows, however, which should be equal to the corresponding steam flow. Some of those meters did not work, however, and for those meters that worked, the measurements were not very accurate.
With the help from the host site, we monitored the product mass flows and concentrations. At the end of the production lines, the final product was carefully weighed and packaged for sale. The concentration of the final product was also carefully controlled. This provided an accurate tracking of system mass flow. The host site conducted special sampling and concentration measurement at each stage of evaporation, so that tomato paste concentrations before and after each evaporator were monitored. The project staff also obtained MVR compressor inlet and discharge parameters, which were monitored by the plant control system.
For both the MVR and the triple effect system, evaporator recirculation pumps were driven by steam turbines. Monitoring of their actual power consumption was almost impossible since reliable measurement of steam flow was not available. Rated power for the three recirculation pumps used in the MVR system were 105 HP, 92 HP, and 88 HP, respectively. Rated power for triple effect recirculation pumps were not available. The project team developed a simple model to estimate the recirculation pump power in the triple effect system.
The condenser in the triple effect system required additional electric power and steam. There were two cooling water recirculation pumps, each rated at 150 HP. The rated fan power at each cell of the cooling towel was 150 HP. Normally, one cooling tower cell was operating, using about 45% of the rated fan power. The condenser vacuum was maintained by an ejector, which consumed about 1500 lb/hr of steam at 150 psig.
3.2 Performance Evaluation Evaporation Rate and Steam Flow At each evaporator, the amount of water evaporation can be calculated as:
After
ContentSolid
Before
ContentSolidnevaporatio C
mC
mm
&&& −=
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)11(PrAfterBefore
FinaloductFinal CCCm −⋅⋅= &
where
FinalC is measured the final product concentration;
BeforeC is the measured product concentration entering an evaporator;
AfterC is the measured product concentration leaving an evaporator;
oductFinalm Pr& is the product mass flow measured at the end of the production line;
ContentSolidm& is the tomato solid content mass flow. It was constant, since there was no tomato paste loss during the process.
For the MVR system, all evaporated vapor was compressed and recycled back into the three evaporators. Therefore, steam flow for the compressor was:
321 MVRnEvaporatioMVRnEvaporatioMVRnEvaporatioCompressor mmmm &&&& ++=
For the triple effect system, the first effect steam input was calculated estimated as:
st
stnEvaporatioeffectSteam mySteamEcono
mm
1
13
&& =
Where
stnEvaporatiom 1& is the first effect evaporation rate;
stmySteamEcono 1 is the first effect steam economy.
The study assumed that the first effect steam economy was constant and the same as the design value of 0.86.
Steam energy input for the MVR compressor The MVR compressor power was calculated as:
)( inletdischCompressorCompressor hhmP −⋅= &
Where
dischh is compressor discharge enthalpy and it was determined by the measured compressor discharge temperature and pressure;
inleth is compressor inlet enthalpy and it was determined by the measured compressor inlet temperature and pressure.
Steam energy input for the triple effect system
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The triple effect energy input was calculated as:
LatenteffectSteameffect hmE ⋅= 33 &&
Where
Latenth is the latent heat of the input steam and is determined by the measured steam temperature, assuming that the steam was saturated.
Evaporator recirculation pump power
pump
pastepastetomatopump
hmP
η∆⋅
=&
Where
pasteh∆ is the increase in tomato paste enthalpy. Without knowing the detailed property of tomato paste, which was largely water anyway, water property was used. According to the MVR manufacturer, the pressure increase by the recirculation pump was about 30 ft. The corresponding enthalpy increase was about 0.04 Btu/lb;
pumpη is the pump efficiency and was assumed to be 60%;
pastetomatom& is the tomato paste flow through the pump. According the MVR manufacturer, the recirculation was about 30 ~ 40 time of evaporator input flow.
The above model provided an estimated pump power that was about 50% higher then the rated power. The pump power for the triple effect system was estimated in a similar way using the same enthalpy and efficiency parameters.
The recirculation pump power was much smaller than the total steam energy. The purpose of this estimation was to demonstrate the order of magnitude of the pump power. Therefore, the large estimation error was tolerable.
Steam and water properties All steam and water property was calculated with a National Institute of Standard Technologies (NIST) software tool.
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4. RESULTS AND DISCUSSION
The host site performed both cold break evaporation and hot break evaporation during the assessment. In the cold break method, the tomato paste had low pectin and was less dense; therefore, it had better heat transfer characteristics and was easy to evaporate. In the hot break method, the tomato enzymatic process was deactivated. The tomato paste was more dense and harder to evaporate. Both processes were run under steady state. For each process, the host site collected two days of data at a two hour interval. The raw data is provided in the appendix 7.1. Table 1 shows the performance evaluation results:
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Table 1 Field Performance Evaluation Results
MVR Triple Effect
Cold Break Hot Break Cold Break Hot Break
Average Steam Energy
(Btu/lb of water evaporation)
50.2 48.5 468 441
Recirculation Pump Power (Btu/lb of water
evaporation)
23.5 30.9 28.5 31.3
Condenser Powers
(Btu/lb of water evaporation)
NA NA 21 23
Condensate Heat Recovery
Potential (Btu/lb of water
evaporation)
81.8 80.2 84.7 81.2
Concentration Change (BRIX)
2.3
(7.5 to 9.8)
2.0
(7.3 to 9.3)
8.3
(10.3 to 18.4)
5.6
(9.7 to 15.3)
Average Evaporation Rate (lb/hr)
44676 39756 117924 104829
Average Steam Flow (lb/hr) NA NA 50454 427591
The monitoring data indicates that both the MVR and the triple effect system were running at a steady state. The MVR evaporator was operated within the temperature range of 176 oF to 187 oF, the corresponding vapor pressure was in the range of 6.7 to 7.7 psia. The compressor had a compression ratio of 1.6. The compressor discharge pressure was 11 to 12.3 psia and discharge temperature was 277 to 293 oF. The calculated compressor efficiency was about 73%.
Figure 7 through Figure 10 illustrate the mass and energy flow around a MVR and a triple effect evaporator. For better comparison, all energy consumption terms are
1 The triple effect steam flow was estimated from the evaporation rate and the steam economy. Without accurate field
measurement data, same values of steam economy, 0.86, were used for both the hot and cold break.
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normalized by the evaporation rate. On average, the MVR system consumed 48.5 and 50.2 Btu of steam energy for evaporating one pound of water in hot and cold break processes respectively. By contrast, the triple effect system required 441 and 468 Btu of steam energy per pound of water evaporated. In this example, the MVR system only used about 11% of the steam energy consumed by the triple effect system.
For the triple effect system, the steam energy consumption was between 46 and 49% of the steam latent heat of 954 Btu/lb. This is greater than one-third of the energy to evaporate water that would be required if each effect had a steam economy of 100%.
Table 2 compares the MVR seasonal energy consumption to what a triple effect system would consume. The estimation was based on energy consumption data from Table 1. The seasonal operation length was assumed to be three month long, with 50% hot break and 50% cold break. The MVR system saved about 39000 MM Btu of energy in one season!
Table 2 Seasonal Energy Savings Achieved by the MVR system
MVR Triple Effect
Tomato processed Ton
6.3 X 105
Total water evaporation lb
9.1 X 107
Steam Energy MM Btu (MM therms)
4500
(0.045)
41500
(0.415)
Condenser Energy MM Btu (MM therms)
NA 2000
(0.02)
Total seasonal savings MM Btu (MM therms)
39000
(0.39)
The results for the tomato paste recirculation pump powers were based on a simplified model, discussed in the previous section. These estimated results show that the recirculation pump power was smaller than the steam energy, especially in the triple effect system. This model did not have enough accuracy to demonstrate which system used less power for recirculation. The power consumption probably depends more on the calandria design. If the calandria has smaller effective surface and higher recirculation speed, higher pump power, would therefore be required to achieve effective heat transfer.
The triple effect system also required additional energy for the condenser operation. The normalized power consumption indicated that it was almost equivalent to the evaporator recirculation pump power.
Steam condensate left the evaporators at high temperatures. For the MVR system, it was at about 180 oF. For the triple effect system, it ranged from 130 oF to 180 oF. If the
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condensate could be used as boiler feed water a large amount of thermal energy could be recovered. This energy savings opportunity is evaluated by comparing condensate enthalpy to that of city supply water, at about 70 oF. Table 1 indicates that the energy recovery potential is very large. It is also worth mentioning that the condensate also had very good water quality, since it was from steam or tomato water vapor. The host site used one third of the condensate as boiler feed water in the triple effect system. For the MVR system, condensate was not used since no live steam was required. Full recovery of condensate was challenging since the more condensate was produced than the total steam demand.
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Figure 7 Mass flow around a MVR evaporator
Figure 8 Energy flow around a MVR evaporator
MVR1 Evaporator
Tomato paste input ~ 140 time of steam flowBRIX = 7.3 %
Recirculation flow~ 33 time of paste input flow
Steam flow ~ 18000 lb/hr ~ 0.7% of tomato paste flow
Compressor Steam Turbine Attemperation flow
Tomato paste output BRIX = 8.0 %
Condensate
Hot Break
To MVR2 & 3 Vapor from MVR2 & 3
MVR 1 Evaporator Tomato paste input
BRIX = 7.3%
Recirculation pump power~ 2.5% of steam energy
Steam energy ~ 18 million Btu/hr
Compressor
Condensate ~ 10% of steam energy
Surface Heat losses
Tomato paste output BRIX = 8.0%
~288 oF
180 oF
Hot Break
Steam Turbine ~ 48.5 Btu/hr, ~ 5% of steam energy
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Figure 9 Mass flow around a triple effect evaporator
Figure 10 Energy flow around a MVR evaporator
Evaporator Tomato paste input ~ 48 time of steam flow
Recirculation flow~ 33 time of paste input flow
Steam flow ~ 37000 lb/hr ~ 1.8% of tomato paste flow
Tomato paste output
Condensate
Hot Break
To the next effect or a condenser
Evaporator Tomato paste input
Recirculation pump power~ 2.0% of steam energy Steam energy
~ 51 million Btu/hr (1st effect) ~ 43 million Btu/hr (2nd effect)~ 37 million Btu/hr (3rd effect)
Condensate 4% ~ 10% of steam energy
Surface Heat losses
Tomato paste output
Hot Break
Steam latent heat reused after the 1st and 2nd effect Release into the atmosphere after the 3rd effect
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5. MVR PERFORMANCE MODEL
An EXCEL based software tool was developed to assess the potential savings from using MVR evaporation technology, instead of a multi-effect system. The snapshots in the following figure illustrated the inputs and outputs of the tool. In addition to energy consumption, the tool also estimates the energy savings potential for recovering steam condensate and steam turbine exhaust. As discussed in the last section, these two items could be significant compared to the primary energy inputs.
Figure 11 and Figure 12 provide the process flow diagram of the model. Detailed calculation formula was provided in previous sections.
Figure 11 Process flow diagram of the triple effect model
Steam Input Parameters
Input Steam input flow
Or First effect steam economy
& input concentration
Evaporator Parameters
Input Evaporation Flow:
Total Evaporation Flow Or
End Product Information: Mass flow & concentration
Input First effect output
concentration & last effect input concentration
Input Condenser related
power & steam consumption
Steam input flow
Total Evaporation
flow
Input Input steam
pressure, temperature,
quality
Total Steam energy
Steam consumption per pound of water
evaporation
Electric power consumption per pound of water
evaporation
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Figure 12 Process flow diagram of the MVR model
Compressor/Fan Parameters
Input Compressor/fan performance:
Compression ratio & efficiency Or
Exhaust Conditions: Temperature & pressure
Evaporator Parameters
Input Evaporation Flow:
Total Evaporation Flow Or
End Product Information: Mass flow & concentration
Input Input & Output Concentration
Input Evaporation TemperatureCompressor
inlet pressure & enthalpy
Compressor discharge
pressure & enthalpy
Input Gear box efficiency
Compressor shaft Power
Evaporation flow
(Compressor flow)
Is the compression
steam driven? Input Motor
efficiency
Electric Power
Consumption Steam energy Consumption
Steam consumption per pound of water
evaporation
Electric power consumption per pound of water
evaporation
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6. CONCLUSIONS
This field performance monitoring study successfully assessed energy consumption of a MVR and a triple effect evaporation system. The MVR system was proven to be much more efficient than the triple effect system. For evaporating one pound of water, the MVR system used from 48.5 to 50.2 Btu of steam energy, which was only about 11% of what the triple effect system consumed. It should also be note that the MVR technology is usually used for tomato paste at low relatively concentrations. To evaporate more concentrated tomato paste higher steam temperatures are required. This, in turn, requires a higher compression ratio. It is difficult to cost effectively achieve compression ratios of more than 1.6.
The recirculation pumps in both system used fair amount of energy, about 24 to 31 Btu per pound of water evaporation. However, this is small compared to the steam energy input in the triple effect system. The difference between the MVR and the triple system can almost be neglected, compared to the steam energy difference. In the triple effect system, the energy consumed by the condenser system was about 21-23 Btu per pound of water evaporation.
The study also developed models for estimating energy consumption of a MVR or a multiple effect system based on some basic design parameters. The models were implemented in an EXCEL based software tool that could help a user estimate energy savings from using a MVR system vs. a multiple effect system.
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7. APPENDIX
7.1 Performance Monitoring Data Table 3 Raw data for the MVR system
Hour MVR 1 Input Brix
MVR 1 Output Brix
MVR 2 Output Brix
MVR 3 Output Brix
End Product flow (lb/hr)
End Product Brix
MVR Evaporation Temp, F
COMP. Inlet PRES, PSIA
COMP DISCH PRES, PSIG
COMP. INLET TEMP, F
COMP DISCH TEMP, F
Cold break, Day 1
0000 7.5 8.2 8.7 9.6 40,961 36.9 181.5 7.6 12.2 180.6 290.3
0200 7.6 8.4 8.7 9.7 38,049 37.0 180.8 7.5 12.0 180.0 288.9
0400 7.6 8.3 8.7 9.6 40,989 36.9 179.7 7.3 11.8 178.8 286.6
0600 7.7 8.2 8.9 9.2 38,049 36.9 181.4 7.5 12.2 180.6 288.6
0800 7.4 8.2 8.6 9.3 39,482 36.8 182.2 7.7 12.3 181.4 291.2
1000 7.4 8.2 8.6 9.2 39,466 37.2 181.7 7.6 12.2 180.9 292.8
1200 39,521 37.3 180.5 7.4 11.9 179.6 290.7
1400 7.1 8.5 9.0 9.5 33,660 36.7 180.1 7.3 11.8 179.1 290.1
1600 7.3 8.1 8.5 10.2 36,587 36.9 180.2 7.3 11.8 179.2 289.1
1800 7.6 8.2 9.2 10.3 36,589 37.0 181.1 7.4 12.0 180.1 289.9
2000 7.5 8.0 8.5 9.2 36,593 37.0 179.7 7.0 11.7 178.7 286.2
2200 7.3 8.9 9.5 10.4 35,161 37.0 179.4 7.1 11.7 178.4 285.0
Cold break, Day 2
0000 7.5 8.2 9.0 10.0 35,144 37.2 179.9 7.2 11.8 178.9 285.5
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0200 7.3 8.1 8.8 10.2 38,069 37.1 180.7 7.4 12.0 179.7 287.2
0400 7.4 8.0 8.6 10.3 38,075 36.9 179.8 7.3 11.8 178.8 283.6
0600 7.0 7.7 8.4 9.6 38,053 37.4 180.3 7.3 11.9 179.2 283.0
0800 7.4 8.0 8.8 9.5 38,057 37.1 180.1 7.3 11.8 179.1 282.1
1000 7.2 7.9 8.5 9.5 40,887 37.1 180.7 7.4 12.0 179.7 283.8
1200 7.5 8.2 8.8 9.5 38,095 37.0 179.7 7.3 11.8 178.6 281.5
1400 7.8 8.5 9.5 10.2 39,509 37.0 179.6 7.2 11.7 178.4 280.8
1600 7.6 9.3 9.0 10.4 40,937 36.9 180.1 7.3 11.9 178.9 281.6
1800 7.5 8.2 8.4 9.5 38,075 36.9 181.0 7.3 12.1 179.9 282.8
2000 7.6 7.8 8.7 9.4 38,072 37.0 180.3 7.3 11.9 179.2 281.6
2200 7.6 8.8 9.3 10.4 39,560 37.1 181.0 7.3 12.1 180.0 284.2
Hot break, Day 1
0000 6.7 8.7 9.2 10.1 54,684 26.1 181.2 7.1 11.6 178.3 282.5
0200 6.8 8.7 9.2 10.3 56,154 26.1 181.0 7.1 11.5 178.0 282.8
0400 7.5 8.9 9.0 10.2 51,840 26.1 181.1 7.2 11.6 178.3 282.7
0600 6.9 7.6 8.5 9.0 54,696 26.0 181.2 7.2 11.6 178.5 283.1
0800 7.0 7.4 8.0 8.7 54,652 26.0 180.3 7.2 11.4 178.2 281.0
1000 6.7 7.0 7.7 8.3 50,351 26.0 180.9 7.2 11.7 178.6 284.3
1200 6.7 7.2 8.0 8.5 50,328 26.0 180.6 7.2 11.6 178.2 285.6
1400 7.5 8.5 8.2 8.6 50,355 26.1 181.5 7.3 11.8 179.2 286.5
1600 8.9 8.9 8.5 9.8 54,666 26.4 179.8 7.0 11.4 177.3 285.5
1800 8.1 8.7 8.8 9.4 51,778 26.2 181.7 7.3 11.8 179.2 287.0
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2000 6.6 7.4 8.2 8.7 51,797 26.0 181.0 7.2 11.6 178.5 286.6
2200 7.8 8.0 8.8 9.5 53,259 25.9 180.4 7.1 11.5 177.7 284.8
Hot break, Day 2
0000 8.7 8.6 10.1 10.4 51,774 26.1 180.3 7.1 11.5 177.8 283.2
0200 7.2 8.4 9.0 9.8 53,216 25.9 181.2 7.2 11.7 178.7 285.3
0400 7.5 8.1 9.5 9.3 51,840 26.1 181.1 7.2 11.6 178.5 285.8
0600 7.8 7.8 8.5 9.1 53,233 26.1 180.6 7.1 11.5 177.9 285.5
0800 7.1 7.5 8.2 8.5 51,792 26.1 181.0 7.2 11.6 178.4 286.0
1000 7.0 7.6 8.1 9.0 53,216 26.1 181.4 7.3 11.8 179.1 288.0
1200 7.2 8.1 8.4 9.1 54,603 26.1 181.1 7.2 11.6 178.6 288.8
1400 7.2 8.0 8.1 8.9 47,477 26.2 181.1 7.2 11.7 178.6 288.6
1600 7.2 7.8 7.9 9.2 50,233 26.1 179.8 7.0 11.4 177.3 285.1
1800 7.5 8.0 8.6 9.5 47,494 26.0 178.6 6.8 11.1 175.8 279.6
2000 7.1 7.6 8.3 9.8 50,361 26.0 178.3 6.7 11.0 175.3 277.1
2200 7.2 8.5 8.5 9.5 48,948 26.0 180.2 6.9 11.4 177.4 278.4
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Table 4 Raw data for the triple effect system
Hour
3rd Effect Input Brix
3rd Effect Output Brix
2nd Effect Output Brix
1st Effect Output Brix
End Product flow (lb/hr)
End Product Brix
1st Effect Steam Temp, F
1st Effect Vapor Temp, F
2nd Effect Vapor Temp, F
3rd Effect Vapor Temp, F
Cold break, Day 1
0000 9.7 11.5 13.7 17.9 68,274 36.9 238 181 155 119
0200 9.7 11.3 13.7 18.2 71,569 37.0 238 181 155 119
0400 9.7 11.3 13.6 18.2 72,466 36.9 238 181 155 119
0600 9.8 12.0 14.3 18.5 72,612 37.0 238 179 154 119
0800 9.7 11.8 14.1 19.1 76,571 37.2 231 173 152 123
1000 12.4 44,258 37.0 171 146 135 130
1200 10.8 13.7 16.2 20.1 80,459 37.0 226 173 150 117
1400 12.0 12.8 14.1 18.2 75,779 36.7 233 176 153 118
1600 11.5 12.5 15.9 18.5 75,026 37.1 237 179 155 119
1800 11.6 12.4 15.1 18.1 70,479 37.0 237 181 155 119
2000 10.5 12.4 15.0 18.1 70,528 37.1 238 181 155 119
2200 9.9 11.5 13.7 18.2 70,529 36.9 238 182 155 118
Cold break, Day 2
0000 10.0 11.8 13.8 18.4 70,382 37.1 238 182 155 118
0200 10.7 11.7 14.2 18.5 74,857 37.0 238 181 155 118
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0400 10.0 11.5 13.8 18.4 73,434 37.1 239 181 155 119
0600 9.9 12.3 13.9 18.4 73,304 37.2 238 181 155 119
0800 10.2 12.4 14.0 18.3 73,045 37.2 238 181 155 119
1000 9.6 11.6 14.2 18.3 78,448 37.2 238 180 156 119
1200 9.6 11.5 14.2 18.3 74,876 37.1 238 180 155 119
1400 10.4 11.6 14.0 18.3 74,282 37.1 238 179 155 119
1600 10.4 11.4 13.8 18.2 71,556 37.0 237 179 154 119
1800 10.3 11.2 13.6 18.1 69,249 36.9 238 180 155 119
2000 10.2 11.3 13.6 18.0 73,469 37.0 238 180 155 120
2200 9.7 12.8 15.0 19.3 72,154 36.7 238 180 154 120
Hot break, Day 1
0000 9.5 12.0 13.3 16.0 107,342 25.6 236 184 158 119
0200 10.6 12.2 13.0 15.1 110,233 25.9 238 185 158 119
0400 10.2 11.9 12.5 15.2 110,205 25.9 239 185 158 119
0600 10.4 12.0 12.5 15.0 103,064 25.6 239 186 158 119
0800 9.6 11.9 12.5 15.1 105,899 25.6 239 186 158 119
1000 9.4 11.8 12.6 15.2 103,036 26.0 239 185 157 119
1200 9.7 12.2 13.0 15.8 105,882 26.2 239 185 157 118
1400 9.4 10.8 12.7 15.1 105,909 26.2 239 184 157 118
1600 9.2 11.8 12.8 15.2 102,978 26.0 239 185 157 119
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1800 9.4 10.3 12.4 15.1 97,259 26.0 239 185 157 119
2000 9.6 10.1 12.3 15.1 107,394 26.0 239 185 158 119
2200 9.7 10.6 12.4 15.2 107,349 26.0 239 185 157 119
Hot break, Day 2
0000 10.1 12.1 12.6 15.4 104,527 26.0 239 185 158 119
0200 9.7 11.8 12.6 15.2 102,792 26.1 239 185 158 119
0400 10.6 11.9 12.7 15.2 105,957 25.8 239 185 157 119
0600 9.1 10.9 12.5 15.2 107,375 26.0 239 185 158 120
0800 9.1 10.6 12.6 15.2 104,418 25.9 239 185 158 120
1000 9.7 11.5 13.0 15.5 107,300 26.0 239 185 158 119
1200 9.6 11.2 13.1 15.6 111,614 26.2 239 186 159 120
1400 9.7 11.2 13.1 15.8 108,671 26.3 239 185 158 120
1600 9.6 10.9 13.0 15.6 104,388 25.9 239 186 158 119
1800 9.7 11.7 12.8 15.4 102,962 26.2 239 185 158 119
2000 9.5 11.5 12.0 15.2 103,020 26.0 239 185 158 120
2200 9.0 11.8 12.9 15.1 104,417 26.2 239 185 157 120
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7.2 Screen Snapshots of the MVR Performance Model
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MVR Performance Evaluation
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Heschong Mahone Group, Inc. Pacific Gas and Electric Company
MVR Performance Evaluation
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Heschong Mahone Group, Inc. Pacific Gas and Electric Company
MVR Performance Evaluation
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7.3 Reference 1. “Energy Use In Tomato Paste Evaporation”, T. R. Rumsey, T. T. Conant, T. Fortis, E.P. Scott, L. D. Pedersen, W. W. Rose, Journal of Food Process Engineering, Volume 7 Issue 2 Page 111-121, April 1984
2. “Evaporation Technology”, GEA Wiegand GmbH
3. “Revised Release on the IAPWS Industrial Formulation 1997, for the Thermodynamic Properties of Water and Steam”, The International Association for the Properties of Water and Steam, Lucerne, Switzerland, August 2007