Development of Purdue
Improved Drying Stove
(PIDS) for Grain Drying
Klein E. Ileleji, PhD.
Associate Professor & Extension Engineer
Associate Prof. Mechanical Engineering (by courtesy)
Agricultural and Biological Engineering Department
Purdue University, West Lafayette, Indiana
Biomass Logistics and Particle Technology Group
Project Team
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Purdue University: Klein Ileleji (PD), Mohan Dutta, Titilayo Okoror,
Corinne Alexander and Jacob Ricker-Gilbert (PIDS Development)
Kwame Nkrumah University of Science and Technology
(KNUST), Kumasi: Ahmad Addo, Komla Dzisi, Ato Bart-Plange
(PIDS Testing in Ghana)
CSIR-Food Research Institute, Accra: Kwame Vowotor, Kafui
Kpodo (Mycotoxin and Pest Mgt. Impact Assessment)
Project in-country coordinator: Kwabena Adu-gyamfi
Other Collaborators and stakeholders:
 USDA-FAS
 George Opit, OSU and Sam McNeill, UK (Rice Husk Ash as
Grain Protectant)
 ACDI/VOCA ADVANCE Project
 Ghana Grains Council
Acknowledgements
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Acknowledge Purdue Global Food Security
Initiative and Global Policy Research Institute
(GPRI) for providing the seed funding for this
project
Biomass Logistics and Particle Technology Group
Problem Statement
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During fact finding visit (USDA-FAS Project)
in October 2010, drying was identified as a
major problem affecting the ability of farmers to
maintain quality of grain in storage.
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Farmers primarily depended on open air solar
drying after harvesting high-moisture grain
during the major season when harvest occurs
and the minor season rains begin.
Grain Drying Challenges in the Humid Tropics
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High post-harvest
losses (PHL) from
improperly dried grains.
Health problems related
to aflatoxin
contamination.
The yield potential in
grain is inhibited by
high PHL.
No alternative
technology to sun
drying yet available.
Exploratory Research Trip in August
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When: August 6 to 12, 2011
Who was involved at Purdue:
 Klein
Ileleji, Ag. & Biological Engineering
 Corinne Alexander, Ag. Economics
 Titilayo Okoror, Public Health
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Goal: Collect data from target community using
culture-centered approach (CCA) to problem
solving, understand and affirm that the problem
targeted is accurate, meet with project partners
and potential collaborators.
Open Air Solar Drying of Maize in
Ejura Market, Ghana
Are Purdue professors playing in
corn being dried or helping Out?
A pile of ear corn waiting to be
shelled and dried in Ejura
Commercial Drying Site in Techiman
Focus Group Discussion with
Farmers in Ejura
Outcome of trip
Successfully conducted focus group
sessions at two locations, Techiman in
Brong-Ahafo region and Ejura in Ashanti
region with a total of 72 participants
(Traders, Farmers and Extension workers)
 Collected 10 hours of audio data from focus
groups.
 Met with our stakeholders
 Confirmed that we are on the right track
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Biomass Logistics and Particle Technology Group
Outcome of Trip
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Received good feedback from agencies:
 KNUST
and CSIR-FPI are on board with project goals.
 UN WFP and IFAD interested in PIDS technology and
will support.
 ACDI-VOCA ADVANCE: Interested and will support
 USAID Ghana: Interested and will support
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The big questions was PIDS performance which
needs to be proven by extensive testing –
quality degradation of corn from smoke and soot
were raised
Outcome of Trip
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We ascertained that drying is a major bottleneck in the
grain value chain which affects:
 Post-harvest losses
 Grain quality and health
 Grain productivity
 Income generation
 Lifelihood
Data is currently being transcribed from Twi language to
English and will be analyzed further
Some results of focus
group survey
compiled by:
Corrine Alexander, PhD.
Michael Jones, MS.
Agricultural Economics Department
Biomass Logistics and Particle Technology Group
Survey of Traders, Farmers and
Extension Agents (n=72)
Demographic
Age
Male
Female
Married
Children
Have Farmland
Farm Size (hectares)
Farm Size (hectares; median)
% Land for Maize Production
How long maize lasts (months)
Purchasing Maize
Average or Percentage
46.2
79.2%
20.8%
86.1%
91.7%
93.0%
23.13
4.52
67.0%
7.3
17.4%
How is Maize Dried?
Maize Drying*
Sun
Machine drying/Dryer
Crib
Keep more days before
harvest
Air dry at barn
Drying floor
Farmers
Traders
Extension
94%
0%
6%
65%
35%
0%
85%
0%
5%
0%
0%
5%
3%
0%
0%
0%
0%
5%
*Can sum to more than 100% because some use more than one drying
method.
How is Maize Dryness Determined?
Moisture Test*
Teeth
Sound
Hands
Moisture meter/ Machine
determines/ Instrument
Leaves turn yellowish
Whole plant becomes dry
Cobs brown/ upside down
Color
Farmers
Traders
Extension
51%
32%
16%
0%
50%
28%
11%
28%
82%
29%
24%
11%
3%
0%
6%
0%
0%
0%
0%
6%
0%
3%
0%
0%
*Can sum to more than 100% because some use more than one test.
Objectives
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Develop a low-cost grain dryer which will be
integrated into the existing homestead cooking
stove for simultaneous cooking and drying of
maize.
Biomass Logistics and Particle Technology Group
Agro-Ecological
Zones in Ghana
DRYER
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Major focus area for
technology
development and
demonstration are
Brong Ahafo and
Ashanti regions of
Ghana
Focus on pilot
study in Ghana
WETTER
Source: WFP
PIDS Concept and
Testing
Acknowledge Undergraduate Researchers:
Nathaniel Bergman (ME, DURI Intern)
Rachel Sinders (ME, DURI Intern)
Megan Shafer (ME, DURI Intern)
Zane Graper (ABE, DURI Intern)
Jinhyun Kim (CHE, Special Project)
Biomass Logistics and Particle Technology Group
Homestead grain granary
Internal structure
Biomass Logistics and Particle Technology Group
Opportunities for an Improved Stove
Biomass Logistics and Particle Technology Group
PIDS Holistic Concept
Target drying entire
corn harvested within
one week
Dry with biomass ag.
residues (target 80%
of fuel needs)
Store dry grain using
PICS technology
Use rice husk ash as
grain protectant from
insects
Biomass Logistics and Particle Technology Group
PIDS Technology (PIDS-I Prototype)
•PIDS technology combines an efficient cooking stove and crop dryer in one unit.
•PIDS concept is an indigenous idea which has been optimized with engineering.
•PIDS can utilize corn cobs as fuel to reduce drying energy and save firewood use.
•PIDS will enable PICS to be used for other grains grown in the humid tropics.
Drying rates of corn at target temperatures
(Using convective air-oven tests)
Biomass Logistics and Particle Technology Group
PIDS Testings
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Evaluate heat distribution and determine maximum temperature rise.
Targeting 70oC (158oF) drying temperature.
Determined dryer capacity and drying rate
Tested two types of fuels (wood and corn cobs)
Determined corn drying rate using lab study
Understand how to control smoke and flame
Evaluate corn quality (by smell and product quality)
Evaluate particulate release
Evaluate energy utilization and efficiency
Redesign PIDS-I Prototype
Document dryer operation
Data collection during tests
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Temperatures in each
heating chamber,
heat transfer plenum,
fire box and ambient
Determined drying
chamber capacity
Determined drying
rate for a 2 ha farm
Biomass Logistics and Particle Technology Group
Temperature Distribution Data in PIDS-I in
Heat Transfer Plenum
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Temperature Distribution Data in PIDS-I in
Drying Tray
Biomass Logistics and Particle Technology Group
Some major findings
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Smoke and coloring from soot is a problem
Achieved the minimum target temperature of
60˚C in Chambers 1 and 2
Heat loss was a problem
Need to understand the use of different
biomass fuels
Wind can be a problem during operation
Need to work on modeling using CFD to
understand heat transfer dynamics
Biomass Logistics and Particle Technology Group
Yes, you’re right, PIDS make great hot dogs!
Questions?
Biomass Logistics and Particle Technology Group