Year 1 26/06/2003-25/06/2004
Survey of regional grain drying and manufacturing and selection of industry partner(s)
This work has been carried out by the Central Mechanical Engineering Research Institute (CMERI) project team in India and especially in West Bengal. The statistical data on grain and seed production (paddy, wheat, maize and oilseeds) have been obtained from West Bengal and other north eastern states.
The CMERI team has conducted a survey on seed farms on the storage conditions of seeds, with an emphasis on the relative humidity and temperature during storage and their effects on germination.
Grain processors, seed and feed industry were the main focus of the survey. Linkages have been established with the Department of Agriculture, Government of West Bengal. This organisation will provide the facilities for experimental studies at Bardhaman Seed Farm, near Durgapur. This work will be expanded to seed farms in other districts:
Arambang Hatcheries Ltd (Feed plant)
Indus Food Products and Equipment Ltd (drying equipment manufacturer).

An introductory seminar was conducted at CMERI in Durgapur. The seminar was attended by representatives of private industry (manufacturers of equipment as well as grain processors), research institutes and universities. Participants came not only from north eastern India but also from countries in the region with similar production patterns (Bangladesh and Thailand). The seminar was a platform for the introduction of the concept of two-stage drying and for the exchange of information on existing drying technologies for grain.
Development of computer-based drying models
The CMERI team has collected thermo-physical data including density, specific heat and thermal conductivity on main varieties of grain crops grown in north eastern India. Two members of the CMERI team visited the drying facilities of the UNSW in 2004 in order to get acquainted with the methodology used for the acquisition of thermo-physical data and development of the existing mathematical models.
The CMERI team collected weather data on temperature and relative humidity from following regions:
Gangetic West Bengal
Sub-Himalayan West Bengal
North-eastern States.

The UNSW team conducted an initial study on the effects of low temperature drying on seed quality, including viability, germination and vigour. A more comprehensive work including the effects of two-stage drying and model development is in progress.

1. Survey of regional grain drying and manufacturing and selection of industry partner(s)
This objective was mostly achieved in the first year of the project. Further statistical data on grain and seed production (paddy, wheat, maize and oilseeds) for the second year of the project were obtained from West Bengal and other northeastern states. Like in the previous year, the emphasis was placed on seed production as being the industry with the most obvious needs of modernisation of the drying system.
The contacts with the dryer manufacturers and seed producers established in the first year of the project were intensified and resulted in collaboration in design and testing of drying equipment.

2. Development of computer-based drying models.
The Central Mechanical Engineering Research Institute (CMERI) team has completed the determination of the thermophysical properties for local varieties of wheat, rice and maize. These include density, specific heat and thermal conductivity. Experiments to determine the sorption isotherms are in progress. The acquisition of weather data on the key experimental sites continues. The techniques of data acquisition have been established during the stay at University of New South Wales (UNSW) by two CMERI scientists in July-August 2004. The validation of existing in-store drying (ISD) software with local crops done. Finite element method (FEM) formulation of mathematical model for steady state process has been done and validated with standard textbook problems. Model development for non-steady state process simulation is in progress.

3. Collaborative construction and testing of prototypes in demonstration trials.
The lab-scale unit of 1st stage fluidized bed dryer including body and control system have been developed and commissioned by the CMERI team. Experiments are being conducted for parameter optimisation. The experimental results are also instrumental in design optimisation of the full-scale prototype to be set up at Burdwan seed farm.

The lab-scale unit of 2nd stage in-store dryer has been designed, built and installed by the CMERI team. The commissioning of the mechanical part of the system has been completed. The control system was designed, built and supplied by University of New South Wales (UNSW) team. The system has been installed, commissioned and tested. The experiments began after the completion of the testing work, i.e. in early August 2005.

Full-scale prototype design for both, the 1st stage fluidised bed dryer and the 2nd stage in-store dryer, have been completed. Installation of both the dryers at Burdwan Seed Farm of Govt. of West Bengal has been done. The drying experiments will start in the coming harvesting season.

The UNSW team continued studies on the effects of two-stage drying on seed quality, including viability, germination and vigour. The studies include the effects of spouted bed, used as an alternative to a fluidised bed dryer as 1st stage dryer, on seed properties. The experimental work provides elements of information required for the development of seed drying model.

4. Training of scientists and manufacturers in the principles and practice of grain dryer design and manufacturing.
An interactive seminar and demonstration session was held on 17th January 2005. Different types of dryers developed in CMERI were demonstrated in actual running condition to the participants. The participants included the policy makers i.e. the government agencies, managerial and technical staff from food processing industries and also grassroots users. The advantages of two-stage system for grain drying, particularly for seed processing and preservation were explained to the participants. Their opinion was sought regarding the suitability of the dryers and suggestions for modification were taken note of.

Work done to date follows the timetable outlined in the project proposal. The third year of project implementation deals with model development and testing of prototypes of dryers. Increased emphasis will be put on the training of manufacturers and users.

During the third year of the project following activities have been carried out:
a) Central Mechanical Engineering Research Institute CMERI team:
The statistics of the annual grain production in West Bengal and the other northeastern states of India (Arunachal Pradesh, Assam, Meghalaya, Mizoram, Tripura, Manipur and Nagaland) have been updated. They included grain and seed production data for paddy, wheat, maize and oilseeds. In West Bengal the total production of paddy rice increased from 14.7 to 15.5 million tonnes whereas the wheat production increased from less than 1 million to more than 1.1 million tonnes between 2003-2004 and 2003-2005. The seed requirement in West Bengal in 2003-04 was 35 thousand tonnes of paddy and 12 thousand tonnes of wheat. In the other northeastern states the demand was 26 thousand tonnes of rice, 41 thousand tonnes of wheat and 5 thousand tonnes of maize seed. Increased demand of seed means increasing demand of mechanical dryers as the safe moisture level for seed storage, 13% wet basis, cannot be maintained under the prevailing climatic conditions without mechanical drying.
The seed production infrastructure has also been surveyed and it was found that there were seven major seed producers (including over 40 state seed farms). Furthermore, the survey has shown that there were 24 major animal feed producers including state owned enterprises in four of the northern states. There are also more than 400 rice mills in West Bengal alone. Finally, there are four major dryer manufacturers in the region.
As a result of the surveys, contacts have been established with nine major seed producing companies as well as with feed mills interested in improving their drying facilities. An important partner is the West Bengal Dept. of Agriculture and especially the seed farm in Burdwan near Durgapur.
The modelling and design work included as follows:
Determination of thermophysical properties of economically important paddy varieties. They included grain size, density, specific heat, thermal conductivity and sorption isotherms at different temperatures. Mathematical models were fitted to these properties when appropriate.
Historical data on temperature, humidity and rainfall have been collected for the representative locations of the following regions
Gangetic West Bengal (Kolkata & Burdwan)
Sub-Himalayan West Bengal (Jalpaiguri)
North-Eastern States (Guwahati)
Weather data loggers have been placed in the WB Govt. farms at Burdwan, Bankura and Jalpaiguri for current data recording and analysis later on.
The thermophysical properties of grain and the weather data are added to the existing drying simulation package in order to provide a predictive tool for design and optimisation of in-store drying systems.
In addition to this work, the CMERI team has designed and tested a laboratory-scale two-stage drying system consisting of a fluidised bed dryer and an in-store dryer as 1st and 2nd stage dryers respectively. The fluidised-bed dryer can be operated in batch or continuous mode, has a capacity of 20 kg paddy/h and can remove moisture from 30% down to 20% wet basis. It has been tested within 60-90C temperature range. The in-store dryer has a capacity of 0.9 m3 and is using near-ambient air. Drying models have been developed for both dryers.
Full-scale prototypes for both the 1st stage fluidized bed dryer (150 kg/h capacity) and the 2nd stage in-store dryer (4.6 m3 capacity) have been installed and commissioned at Burdwan seed farm of Govt. of West Bengal. Experiments of the two stage drying system with freshly harvested grains are in progress in order to validate the results of the laboratory tests and to demonstrate the system to the users. In addition to research activities, CMERI hosted the 4th Asia Pacific Drying Conference in December 2005 (ADC05) in Kolkata where the principle and applications of the two-stage drying system were demonstrated.
b) Food Science and Technology, University of New South Wales team
Extensive work on the modelling of two-stage drying of seed of three major grain crops: rice, wheat and maize. The research work includes the use of fluidised and spouted-bed dryers and of an in-store dryer using near-ambient air. Seed quality attributes such as viability and vigour are included in the model.
A further major research activity is the development of finite elements method (FEM) to describe the drying behaviour of a single kernel. FEM allows to study the following areas:
Effect of changes in drying conditions
Fissuring
Surface 'melting' effect at high temperature
Directional drying
Finally, both teams are developing training tutorials based on the computer assisted learning principle for dissemination of project outputs among the potential users.