ENERGY RECOVERY AND ODOUR REDUCTION IN PETFOOD PRODUCTION

Tjitze Smit

PROGRAMME

1. About Graintec 2. Odour reduction3. Energy recovery4. Summary remarks

Independent, privately owned company Engineering, contracting and project management company Design – Execute – Install – Maintain Turnkey supplies More than 250 references worldwide Serving two main segments – producers of

Extruded Fish feedExtruded Pet food

ABOUT GRAINTEC

Worldwide assignments …

OUR KEY CLIENTSAll Internationally Operating Companies

And many more …

ODOUR Reduction

0

20.000

40.000

60.000

80.000

Aqua Feed Plant Pet Food Plant Animal Feed Plant

Aqua Feed Plant 5000 75000 60000 27000 2000

Pet Food Plant 4000 25000 50000 25000 1500

Animal Feed Plant 2600 12500 1500

Hammer mill

Extruder flash-off

Dryer exhaust

Cooler exhaust

Plant vent.

ODOUR CONCENTRATIONS OU/M3

Odour concentration may fluctuate significantly from plant to plant!

0

1

2

3

4

5

6

0 20 40 60 80 100 120

Extremely strong

Very strong

Strong

Odour Intensity:When the concentration of (odorous) compounds is several times higher than the odour threshold, the human nose does not perceive it like that.

The figure shows the relationship. It also explains why a relatively high reduction of the odour emission (in percentage) will not necessarily be perceived as such.

Perceptible

Weak

Very weak

No odour

Odour concentration Ou/m³

ODOUR PERCEPTION AND INTENSITY

ODOUR EMISSION OU/H PET FOOD FACTORY 2 LINES

13% of total odour emission

Solution: Cleaning efficiency

1. Chimney 0 % (Only dilution)

2. Ozone Reactor (Plasma) 70 – 85 %

3. Bio or Chemical Scrubber(s) 70 – 90 %

4. Bio Filter 70 – 95 %

5. RTO Oxidizing 90 – 98 %

6. Recirculation/Condensation incl. Coal Filter 98 – 99 %

ENVIRONMENTAL SOLUTIONS

1. CHIMNEY: EFFICIENCY 0%

Dryer/cooler

Cyclone/filter

Chimney

Photo left:Plume of smoke (winter conditions)

Photo right:Stack/chimney taller than 100 m is not unusual

2. OZONE REACTOR (PLASMA): EFFICIENCY 70 - 85%

Dryer/cooler Cyclone/filterChimney

Reactor

Photo left:APP plasma unit

3. BIO/CHEM. OR SEA WATER SCRUBBER:EFFICIENCY 70 - 90%

Dryer/cooler Cyclone/filter ScrubberChimney

Photo left:Sea water scrubbers

Photo right:Chemical scrubber located indoors

4. BIO FILTER: EFFICIENCY 70 - 95%

Dryer/cooler Cyclone/filter Scrubber Bio filter

Photo left:Bio filter with wood chips

Photo right:Fresh water scrubber

5. RTO OXIDIZING: EFFICIENCY 90 - 98%

Dryer/coolerCyclone/filter

Chimney

RTOoxidizer

Photo left:Regenerative thermal oxidizers

6A. TOTAL RECIRCULATION INCL. COAL FILTER: EFFICIENCY 98 – 99%

Dryer/cooler Cyclone/filter Air treatment Bio/ Coal filter

Photo left:Air treatment unit incl. bag filter

Photo right:Cooling tower

6B. ENERGY RECOVERY AND ODOUR REDUCTION

Reduction in odour emission: 85 - 98%Thermal energy recovery: ~ 15 – 50 kWh/ton

Solution: Cleaning efficiency

Capital investment costs for each cbm air/h to be cleaned

Annual operating costs for each cbm air/h to be cleaned

Chimney 0 % Very low Very Low

Ozone/plasma Reactor 70 – 85 % Low High

Bio/Chemical or Sea Water Scrubber(s)

70 – 90 % High High

Bio Filter 70 – 95 % Medium High

RTO Oxidizing 90 – 98 % High Very High

Recirculation/Condensa-tion incl. Coal/Bio Filter

98 – 99 % High Low*

SUMMARY

* The annual operating cost for this solution is very low because the solution includes energy recovery!

ENERGY RECOVERY

81 102130141

189

250222

291

380

050

100150200250300350400

Low Average High

kW

h/t

on

of

fin

al

pro

du

ct

Energy Consumption Extruded Feed Production

Electrical

Thermal

Total

ENERGY CONSUMPTION

The total energy consumption (thermal and electrical) can normally be reduced to less than 220 kWh per ton of final product in extruded feed, and drying is the most energy consuming process

ENERGY DISTRIBUTION

THERMAL ENERGY CONSUMPTION

ELECTRICAL ENERGY CONSUMPTION

Thermal energy for drying accounts for 60% of the total thermal energy consumption 4 solutions to recover energy from drying:

1. Cross flow air/air heat exchanger2. Air/water heat exchanger3. Air/water heat exchanger in combination with high temperature heat pumps 4. Air/water heat exchanger and recirculation of dryer air

All 4 solutions will in addition to energy recovery have an odour reduction effect off 30 – 85%Additionnal air treatment system can increase odour reduction effect to 99%

THERMAL ENERGY RECOVERY SOLUTIONS

Cross flow air to air exchanger (HE)Up to 50% energy recovery possible Condensation in air and low temperature energy may be a problemOdour reduction effect below 50%

SOLUTION 1: CROSS FLOW AIR/AIR HEAT EXCHANGER

HE

DRYER/COOLER

Air to water exchangers (HE)Up to 40% energy recovery possibleCondensation and low temperature energy may be a problemOdour reduction effect below 50%

SOLUTION 2: AIR/WATER HEAT EXCHANGER

HE

HE

DRYER/COOLER

SOLUTION 3: AIR/WATER HEAT EXCHANGER IN COMBINATION WITH HIGH TEMPERATURE HEAT PUMP

Air to water exchangers (HE) in combination with high temperature (80 – 110°C) heat pump (HP) Up to 70 % energy recovery possible Condensation in air may be a problemOdour reduction effect above 50%

DRYER/COOLER

HE

HE

HP

Air to water exchangers in combination with recirculation of dryer air Up to 20% energy recovery possible Condensation in air may be a problemHygiene risk in recirculation air to be consideredOdour reduction effect above 85%

SOLUTION 4: AIR/WATER HEAT EXCHANGER AND RECIRCULATION OF DRYER AIR

DRYER/COOLER

HE

SIMULATION PROGRAM AND PINCH ANALYSES

Energy recovery of dryer exhaust air and other process air sources may save 20 – 100 kWh of thermal energy per ton of final product Integration of energy, odour and carbon dioxide reducing technologies are in most cases a very cost effective solutionNew technology inventions in the fields of heat exchangers and heat pumps will bring further future possibilities to recover energy and reduce carbon dioxide emissions from the pet food industry

SUMMARY

QUESTIONS ?

THANK YOU FOR YOUR ATTENTION !