A novel method for analyzing grain facility heat treatment data

Hulya AKDOGAN

Mark CASADA

Alan DOWDY

Bh. SUBRAMANYAM

A novel method for analyzing grain facility heat treatment data~ Introduction ~

Management of Stored Product Insects (SPI) in grain processing facilities (chemical methods versus high temperatures)

Heat treatment - a viable alternative to chemicals

Target temperature 50oC, typically 50o to 60oC

Temp., duration of exposure, species, stages of development, RH determines insect survival.

1

A novel method for analyzing grain facility heat treatment data ~ Materials/Methods (1/2) ~

Pilot flour mill & cleaning house at KSU (6/99 & 8/99)

Two heating systems: gas & electricGas heating: heaters outside the building; hot air

delivered inside the building through nylon ducts

Electric heating: heaters within the building; power & monitoring cables running outside the building

Fans used for uniform temperature distribution

Time/temperature/RH recorded every 10 min at floor level; 16-22 data loggers per room.

2

Effectiveness of heat treatments compared by surface area method

Surfer software used to calculate the surface areas

% floor surface area < 50oC as a function of time (duration of the heat treatment) and % floor surface area maximum floor temperature

Contour maps of maximum floor temperature

A novel method for analyzing grain facility heat treatment data ~ Materials/Methods (2/2) ~

3

A novel method for analyzing grain facility heat treatment data ~ Results ~

Different heating patterns

4

Location

Mill 2 Mill 3 Mill 4 CH 1 CH 2 CH 3 CH 4 Entire facilty

Lag

tim

e (h

)

0

5

10

15

20

25

Gas heatingElectric heating

Lag times (time delays)

Red- electric heatingBlack- gas heating

Duration of treatment (h)

Flo

or

surf

ace

area

< 5

0C

(%

)

Mill 3

0 10 20 30 40 50

0

20

40

60

80

100

Flour Mill 3

5

A novel method for analyzing grain facility heat treatment data ~ Results ~

The surface area approachSurface areas calculated from Surfer outputsNormalized % surface area values for easy

comparison

iA

fA

iAtA

normA

)(

Anorm is the nondimensional area under 50C A(t) is the percent area < 50C at time t Ai is the % area < 50C at the beginning of heat treatment

Af is the % area < 50C at the end of heat treatment.

Nonlinear regression - PROC NLIN procedure (SAS)

6

A novel method for analyzing grain facility heat treatment data ~ Results ~

The surface area approach (ctd.)

A log-logistic equation used:

cetemperaturbeAreaSurfacePercent

10log11

Pseudo-R2 calculated. Ranged from 0.90-0.99.

SSTSSR

RPseudo 12

SSR= Residuals Sum of Squares

SST=Total Sum of Squares

7

Duration of treatment vs. % floor surface area < 50C

Cleaning house 1

0 10 20 30 40 500

20

40

60

80

100

Cleaning house 2

0 10 20 30 40 500

20

40

60

80

100

Cleaning house 4

Treatment time (h)

0 10 20 30 40 500

20

40

60

80

100

Mill 2

0 10 20 30 40 500

20

40

60

80

100

Mill 3

0 10 20 30 40 500

20

40

60

80

100Cleaning house 3

0 10 20 30 40 500

20

40

60

80

100

Mill 4

0 10 20 30 40 50

Sur

face

are

a un

der

50o C

(%

)

0

20

40

60

80

100

8

Flour Mill 4

Mill 4

0 10 20 30 40 50

0

20

40

60

80

100

Red-electric heatingBlack-gas heating

Duration of treatment (h)

Flo

or

surf

ace

area

< 5

0C

(%

)

9

Cleaning house 1

Cleaning house 1

0 10 20 30 40 50

0

20

40

60

80

100

Red-electric heatingBlack-gas heating

Duration of treatment (h)

Flo

or

surf

ace

area

< 5

0C

(%

)

10

Cleaning house 4

Cleaning house 4

0 10 20 30 40 50

0

20

40

60

80

100

Red-electric heatingBlack-gas heating

Duration of treatment (h)

Flo

or

surf

ace

area

< 5

0C

(%

)

11

Mill 2

Temperature (oC)

40 45 50 55 60 65 70 75 80 85

Sur

face

are

a (%

)

0

20

40

60

80

100

Max. floor temp. vs. % floor surface area

red-electric heatingblack-gas heating

Mill 2

12

A novel method for analyzing grain facility heat treatment data ~ Results ~

Time delays (lag times) Gas heating

slower at the beginning Electric heating

mostly shorter compared to gas heating

Effectiveness of treatment (T<50oC) Gas heating

less under-heated areas observed Electric heating

more under-heated areas observed

13

A novel method for analyzing grain facility heat treatment data ~ Maximum temperature distributions ~

45°C

50°C

55°C

60°C

70°C

T e c H e a t

T e m p A i r

C l e a n i n g h o u s e M i l l

C l e a n i n g h o u s e M i l l

N o r t hGas heating

Electric heating

Floor 1

Floor 1

Floor 2

Floor 2

Floor 4

Floor 3

Floor 3

Floor 4

Flour mill 1 was not studied.

---------------------------------------------------------

---------------------------------------------------------

14

40°C

45°C

50°C

55°C

60°C

65°C

70°C

75°C

80°C

85°C

F lo o r 1

F lo o r 2

F lo o r 3

F lo o r 4

N >

Gas heating

Cleaning house Flour millCleaning house

15

40°C

45°C

50°C

55°C

60°C

65°C

70°C

75°C

80°C

85°C

F lo o r 1

F lo o r 4

F lo o r 3

F lo o r 2

N >

Electric heating

Flour millCleaning house

16

A novel method for analyzing grain facility heat treatment data ~ Main points ~

Heat treatment as an alternative to chemical treatments

Different heating patterns of gas and electric heating-Time delays; % A under/over-heated

Sufficient heat treatment & uniform heat distribution

Quantification & identification of over-heated & under-heated areas

Characterizing the heating pattern of each method via modeling (log-logistic eqn.)

17

Thank you

The End