food processing waste stream utilization · pdf filefind opportunities to recover waste heat...

ENHANCING RESOURCE EFFICIENCY AND SUSTAINABILITY IN FOOD PROCESSING:

FOOD PROCESSING WASTE STREAM UTILIZATION

CHRISTOPHER SIMMONS, PHDFOOD SCIENCE & TECHNOLOGY

ENERGY EFFICIENCY CENTERUNIVERSITY OF CALIFORNIA, DAVIS

GOALFind opportunities to recover waste heat in food processing and develop applications for that recovered heat.

Waste Heat Recovery

Tomato processing example:Tomato water – hot condensate from evaporation step of paste production.

EVAPORATOR

Condensed water (Tomato water)

(120 – 200 °F)

Waste Heat Recovery

*California Energy Commission. Industrial Water Energy Nexus Assessment: Campbell Soup California Tomato Processing Facility. Sacramento:California Energy Commission, 2013. Print.

SAVED

WASTE HEAT RECOVERY TO OFFSET STEAM PRODUCTION

How many MMBTU?

ELECTRICITY

236,800 kWh/season$35,520/season

Reusing the cooled tomato provides further energy savings. WELL WATER

PUMPING176,400 kWh/season$22,050/seasonELECTRICITY SAVED

WASTEWATER TREATMENT29,400 kWh/season$4,305/seasonELECTRICITY SAVED

FACILITY SAVINGS = $???/SEASON

Waste Heat Recovery

CONCEPTUse tomato water waste heat as part of the hot break.

HEAT EXCHANGER

Crushed tomatoes at 200 °F

Chopped tomatoes at 75 °F

Hot steam

Condensate

Waste Heat Recovery

HEAT EXCHANGER


Hot steam

Less hot steam/water

EVAPORATOR

Hot tomato water

HEAT EXCHANGER


Tomato juice Tomato paste

Cooler tomato water


Waste Heat Recovery

Modeling heat transfer in first stage of a 2-stage hot break process:

Inputs:1. Tomato temperature2. Tomato flow rate3. Tomato water temperature4. Tomato water flow rate5. Type of heat exchanger6. Heat exchanger heat transfer

coefficient and area

Waste Heat Recovery

Image: Allegheny Bradford

Hot tomato water

Hot chopped tomatoes

Coolchopped tomatoes

Cooltomato water

OBJECTIVE 2 – MODELING 1ST STAGE OF 2-STAGE HOT BREAK

Effectiveness-NTU method:

Heat transfer rate: q=mcpΔTHeat capacity rate: C=ṁcp

KNOWN𝑁𝑇𝑈 =

𝑈𝐴

𝐶𝑚𝑖𝑛Number of transfer units (NTU):

𝑞𝑚𝑎𝑥 = 𝐶𝑚𝑖𝑛 𝑇𝑇𝑊,𝑖𝑛 − 𝑇𝐶𝑇,𝑖𝑛

Maximum heat transfer rate (W):

Heat capacity rate ratio:=𝐶𝑚𝑖𝑛

𝐶𝑚𝑎𝑥

Calculated from facility data and heat exchanger properties

Effectiveness: 𝜀(𝑁𝑇𝑈,𝐶𝑚𝑖𝑛

𝐶𝑚𝑎𝑥) =

𝑞

𝑞𝑚𝑎𝑥

DETERMINE

OUTPUTHeat transfer rate to tomatoes (energy savings), qTemperature of tomatoes at end of first stage, TCT,out

Time to heat tomatoes in first stage, t

Waste Heat Recovery

Image: Allegheny Bradford

Hot tomato water32.7 kg/s

74 °C

Cool chopped tomatoes

73.5 kg/s

26.7 °C

Modeling results:

>9 million kWh recovered over 2250 hr season

Offset 10.6 million kWh of natural gas energy in boilers

$217,000 in natural gas savings/season

Cool tomato water

44.6 °C

Hot chopped tomatoes

40.3 °C

Waste to Energy

GOALEnhance conversion of agricultural and food processing residues into renewable energy.

Anaerobic Digestion: Converting waste organic matter to biofuel

Digester

Biogas•Methane•Carbon dioxide

Residual biomass and waterFood processing waste

Waste to Energy

Waste to Energy

Anaerobic digestion is a complex network of microbial activity.

There are many potential points of inhibition.

We can use recent advances in metagenomics to understand and design more robust and functional digester communities.

Waste to Energy

Xylanase activity Endoglucanase activity

Thermophilic community has more xylanase and

endoglucanase activity than mesophilic community.

thermophilic

mesophilic

Example: finding bacteria and enzymes for high-solids deconstruction of rice straw:

GTGGTTGCACAAAAAACGTTGCTCCCGATTGTGTGAGACCACATGTGTTGATGGGTGTCGATCCCAACA









































Waste to Energy

Waste to Energy

0

10

20

30

40

50

60

70

80

90

100

Mesophilicenrichment

Thermophilicenrichment

All other phyla

Fungi

Bacteroidetes

Proteobacteria

Firmicutes

Actinobacteria

0

10

20

30

40

50

60

70

80

90

100

Mesophilic

enrichment

Thermophilic

enrichment

Re

lativ

e a

bu

nd

an

ce

(%

)

Waste to Energy

Thermophilic

community

Mesophilic

community

Cellobiohydrolases with

carbohydrate binding

module 2 are

overrepresented in

thermophilic community

Waste to Energy

Example: Using microbial communities for wastewater treatment, electricity generation, and desalination:

anode cathodesaline water

+

+

+

-

-

-

wastewater

exoelectrogenicbacteria

cationexchange

membrane

anion exchange

membrane

Simultaneous

-wastewater treatment

-electricity generation

-water desalination

GOALS

• Develop new applications for agricultural and food processing solids wastes.

• Turn waste streams into co-products.

• Advance sustainable waste management and agriculture.

Solid Waste Management

Inactivate plant

pathogens and

weed seeds in soil

via passive solar

heating and

microbial activity.

Replaces need for soil fumigants.

Adds nutrients to

soil.


Biosolarization

Field soilStable green

waste compost

Agricultural or food

processing organic

residues

Induce microbial activity with waste biomass soil amendment:

+ +


Plastic tarp

Soil

Acid fermentation:-Lactic acid-Butyric acid-Acetic acid



Inactivation of black mustard seeds:Combination of soil microbial activity and passive solar heating is significantly more effective than heating alone.

NATIVE SOIL

AMENDED SOIL

S = 100% soil

C = 100% compost

SCW = 90% soil

+ 8% compost

+ 2% wheat bran

n=5

Nonmetric

multidimensional scaling

2D representation of

community similarity.

Similar communities

appear closer together.

NON-SOLARIZED

CONTROLS


Amended soil shows enrichment of potentially

beneficial bacteria following solarization.

•Azotobacter beijerinckii

enriched in amended soil

(10.5% of total community).

•Azotobacter species can

secrete phytohormones.

•Not detected in native soil

after solarization.


food processing waste stream utilization · pdf filefind opportunities to recover waste heat...

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