Heat Treatment of Empty Metal Storage Bins Dennis R. Tilley, Mark - - PowerPoint PPT Presentation

Heat Treatment of Empty Metal Storage Bins

Dennis R. Tilley, Mark E. Casada, & Frank H. Arthur

USDA-ARS Grain Marketing and Production Research Center Manhattan, KS

Outline

* Project Overview * Objective * Equipment and Process Used * Temperatures and Insect Mortality Results * Conclusions * Future Plans

Introduction

* Residual chemicals currently recommended for pre-binning sanitation * Heat treatments have been successfully applied in processing facilities to control insects (alternative to Methyl Bromide) * Bins with full drying floor particularly difficult for sanitation * GMPRC Pilot Plant had a bin needing sanitation

Project Overview

*4,000 bu metal drying bin (perforated floor). *Large variable speed drying fan. *1 h.p. aeration fan for circulation in the bin. *Perforated floor was covered with tarp. *Introduced live insects to check mortality.

Trap Counts Trap Counts

16 months after After Before

50 100 150 200 250

Number of Insects

W e s t N

• r

t h E a s t W e s t N

• r

t h E a s t

Top B

• t

t

• m

Larvae Exiting Bin Larvae Exiting Bin

Project Objectives

*Develop a practical method to obtain a uniform heat distribution of 120°F within the bin. *Evaluate insect mortality rates. *Develop an economic model describing the most cost effective method of using heat to sanitize steel grain bins prior to filling.

Heating Equipment

Duct Heater 65,000 - 85,000 - 100,000 BTU Forced Air Propane Heaters

18 kW or 61,400 BTU

Three species added to arenas’ Three species added to arenas’

Rice weevil

(Sitophilus oryzae)

Red flour beetle

(Tribolium castaneum)

Lesser grain borer

(Rhyzopertha dominica)

Arena

* 3 species of insects. * HOBO Temperature Instrument. * 1 tsp of cracked wheat

Arena

* 5 Control located

• utside of bin..

Arena Locations

* 5 Below aeration

floor

* 5 Above Aeration

floor

* 7 One foot above

floor

* 3 Upper Portions

• f bin

North South East West

Arena

Length of tests:

• 12 hr
• 27 hr
• 40 hr

North South East West

Electric Duct Heater

Inlet of 18 kW Heater Manifold and Aeration Fan

Temperature and Time Required to Kill Temperature and Time Required to Kill

20 40 60 80 100 120 Time Required (Minutes) 120°F 140°F 160°F

Granary Weevil (all stages) Rice Weevil (adults) Rice Weevil (larvae) Sawtoothed Grain Beetle

* Evans, D. E. 1981. The influence of some biological and physical factors on the heat tolerance relationships for R. dominica and S. oryzae. J. Stored Prod. Res. 17:656-72.

18 kW Heating Element

Summary of Kill Results:

R W R F B L G B 12 27 40 20 40 60 80 100

% Kill Species Time (hours)

Heating Equipment

Duct Heater 65,000 - 85,000 - 100,000 BTU Forced Air Propane Heaters

18 kW or 61,400 BTU

Propane Heat Treatment

• 4,000 bu bin
• Perforated floor is

covered with a tarp.

• Interior circulation

system removed

• Fuel consumption:

65K 100K

gallons/hr 0.7 1.1 pounds/hr 3.0 4.6

Propane 100,000 BTU/hr 4 Hour Test

Above Drying Floor Average Bin Temperatures

70.0 80.0 90.0 100.0 110.0 120.0 130.0 140.0 150.0 160.0 170.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Time (hr) Te mp. °F

Control Bin Avg. Temperature Ambient Temp.

100 % Kill

Propane 100,000 BTU/hr 4 Hour Test

Below Drying Floor Average Bin Temperatures

60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 220.0 240.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Time (hr)

• Temp. °F

Control Bin Avg. Temperature Ambient Temp. Center South West East North

100 % Kill

Conclusion

* Disinfesting a steel grain bin using heat is a viable option. * Distributing heat uniformly to all parts of the concrete floor is a key for successful treatment.

Future Plans

*Repeat treatments with propane heater at 65,000 BTU *Spot electric heater using recirculated air. *Controlled time motion study of sanitizing a bin by removing flooring and manually cleaning. *Development of economic model to optimize the most efficient and practical application.

Questions