Agricultural Engineering

Introduction:

Pulses are basically grain legumes. They occupy an important place in human nutrition due to their high protein content than cereal grains. In Indian dietary regime it occupies an important place. Since majority of Indians are vegetarians, they depend largely on grain legumes (pulses) for their dietary protein. Legumes contribute a major portion of lysine in the vegetarian diet. They are also a fairly good source of vitamins like thiamine, niacine, riboflavin and much needed iron. Therefore its quality availability to the common man is a major challenge. Since recovery was poor in traditional technologies, adoption of modern technology will go a long way in meeting the need of the common man.

Pulses Production in India:

India is one of the major pulse growing countries in the world. The production of pulses in India in 2001-02 was 13.19 million tonnes, which was about 27-28% of the world production. Among the different pulses grown in the country, the respective share of production has been : chickpea (bengal gram / chana) 40.50% ; pigeon pea (tur /arhar) 17.90%; green gram (moong) 9.20%; black gram ( urad) 9.10% ; lentils ( masur) 6.10% and other minor pulses 17.20%. Among the important states engaged in growing pulses have been : Madhya Pradesh 22.90% ; Uttar Pradesh 18.12% ; Maharashtra 14.25% ; Rajasthan 10.84%; Andhra Pradesh 8.64% ; Karnataka 5.76% and others 19.49% . Thus about 80.51% of the pulses supply is contributed by five major states. Off late the production and area under pulses cultivation in the country has been stagnated. This is because of unfavorable climatic and ecological factors, non availability of high yielding varieties, improper research support, socio economic factors and constraints in post harvest technology. As a result of stagnating production and surging population, the per capita availability of pulses has come down from 70 grams/ day in 1960's to 27 grams/day in 2001. The same was only about 34% of the World Health Organization's recommendation of 80 grams/capita/day.

Consumption pattern of pulses :

Most of the legumes in raw form contain a wide variety of anti-nutritional factors. In addition, many of the grain legumes cause flatulence. Thus there exists a need for processing the grain legumes into consumable form. The various grain legumes in our country is consumed in the following ways:

Main Uses of Pulses in India are as follows:

The Pulse Milling Process:

In India most of the pulses are consumed in dehusked and split form. Thus processing of pulses assumes a lot of importance. Pulses processing industry helps in processing the raw grain legumes/ pulses into edible form. Processing activity is undertaken at 3 different levels. They are:

i. Primary processing: Primary processing activities consist of production of cleaned, graded, packaged pulses.

ii. Secondary processing: Under secondary processing activities such as dehusking, splitting, polishing, tumeric/ spices/ salt coating and powdered besan and packaged dal are done.

iii. Tertiary processing: These activities mostly consist of preparation of roasted, fried dal and other associated dal products.

Pulses are usually converted into Dal by dehusking/ decutilating and splitting. Both dry and wet milling processes are employed. Mostly carborundum emery rollers are used for dehusking and burr grinders for splitting the pulses. Decutilating is seldom complete in single pass thereby requiring multiple passes. Each pass produces around 1.5 to 2% fines thereby reducing the overall recovery of dal during the milling operation.

Basic processes in dal milling are cleaning, grading, conditioning, dehusking, splitting, separation, polishing and bagging. Major variation is involved with dehusking process only. Dals like Arahar, Urad, Moong and Lentil are difficult to dehusk as a result repeated operations by dehusking rollers are required. Repeated soaking, drying, tempering is done to loosen portions of husk sticking after rolling operations. Sometimes Linseed oil is also used during dry milling operation to impart shine or better appeal to the milled dal.

The removal of the outer layer of husk and splitting the grain into two equal halves is known as milling of pulses. To facilitate dehusking and splitting of pulses alternate wetting and drying method is used. In India traditional milling methods produce dehusked split pulses. Loosening of husk by conditioning is insufficient in traditional methods. To obtain complete dehusking of the grains a large number of abrasive force is applied resulting in high losses in the form of brokens and powder. Yield of split & dehusked pulses in traditional mills are only 65 to 75% due to the above losses compared to 88 to 89% potential yield.

Procedure for pulse milling: Basically two types of conventional pulses milling methods is commonly used in India. They are :

• Wet milling operations
• Dry milling operations

Flow diagram of wet milling of pulses:

Pulses

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Cleaning è chaffs, dirts, etc.

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Soaking

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Mixing with red soil

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Conditioning

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Dehusking and splitting -- mixture of husk, small broken and powder

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Separation and Grading

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Dehusked and split pulses

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Bagging

Flow diagram for dry milling of pulses:

Pulses

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Cleaning è chaffs, dirts, etc.

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Pitting

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Pretreatment with Linseed Oil

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Conditioning

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Dehusking and splitting è mixture of husk, small broken and powder

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Grading

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Polishing

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Grade I Pulses

Description of various Unit Operations:

• Cleaning and Grading

  Cleaning helps in removal of dust, chaff, dirt, grits, etc. from the pulses. Grading is done to segregate the grain legumes of desired shape and size . The same is done using a reel or rotative screen type cleaner.

• Pitting

  An emery roller machine is used for cracking the husk layer and for scratching of clean pulses passing through it. This is done for loosening the husk from sticking to the cotyledons in order to facilitate subsequent oil penetration in the following unit operations. Gradually the clearance between the emery roller and cage (housing) is narrowed from inlet to outlet. Cracking and scratching of husk takes place mainly by friction between pulses and emery as the material is passed through the narrowing clearance. During the operation some of the pulses are dehusked and split which are separated by sieving.

• Pretreatment with Oil

  The scratched or pitted material passes through a screw conveyer and mixing of some edible oil like linseed oil is done in it. The linseed oil is used at the rate of 1.5 to 2.5 kg/tonne of pulses. Pulses coming out of the screw conveyer are kept on floors for about 12 hours to diffuse the oil.

• Conditioning

  Pulses are conditioned by alternate soaking/ wetting , drying and tempering. Moisture (3.5%) is added to the pulses after sun drying for a certain period and tempering is done for about eight hours. The grain is dried in the sun again. Until all pulses are sufficiently conditioned the whole process of alternate wetting and drying is continued for two to four days. Pulses are finally dried to about 10 to 12% moisture content prior to dehusking and splitting.

• Dehusking and Splitting

  For dehusking of conditioned pulses carborundum coated emery rollers are used. In one pass about 50% of pulses are dehusked. Dehusked pulses are split into two parts. Dehusked split pulses are separated by sieving and the husk is aspirated off. Unsplit dehusked pulses and tail pulses are again dehusked and milled in a similar way. For complete dehusking and splitting the whole process is repeated two to three times.

• Polishing

  Polishing is completed by treating dehusked and split pulses with a small quantity of oil and/or water.

  Status of Pulses Processing Industry in India :

  Dal milling industry is one of the major agro processing industries in India. Out of the total production of 13.19 million tonnes of pulse in the country, 75% is processed by these dal mills. There were about 2000 dal mills in the country in 1972. The numbers grew steadily to 6000 units in 1982, 12000 units in 1995 and 14000 units during the year 1999-2000. Most of the dal mills in the country are concentrated in selected pockets of the country i.e. pulses producing areas such as Indore (MP), Jalgaon, Akola and Nagpur (Maharashtra) and in or near major consumption centres such as Kolkata, Mumbai, Chennai, Hyderabad and Delhi. The units are mostly traditional ones. They are capital intensive and energy sapping in nature. The dehusking efficiency in traditional mills is quite low. Moreover, the yield of dehusked and splitted pulses in traditional mills is about 65-70 % in comparison to 88-89% maximum potential recovery of splits. Thus, there is excessive loss of pulse cotyleadons and embroyos in the form of brokens and powdered grains (5- 15%). The industry is also besieged with other problems such as low domestic availability of pulses, high block capital and working capital requirement and presence of large number of intermediaries in pulses procurement and marketing of finished products.

  Need for improved Dal Mills:

  The present losses being encountered by the milling industry can be minimized to a great extent by the use of improved dal mills. These dal mills are highly versatile and energy efficient. Many agricultural universities , ICAR institutions in the country have developed modern improved dal mills . Some of these institutes are PKV Akola, CFTRI- Mysore, GBPUAT- Pantnagar, CIAE- Bhopal, IIPR-Kanpur, TNAU- Coimbatore and IARI- New Delhi. The improved dal mills have dehusking efficiency of about 95% and the yield of split pulses is about 80-85% depending on the variety of pulse and conditioning of the pulse grain.

  Some of the improved dal mill machinery are :

  Modern Machinery for Pulses Processing
  

  i. Roller machine: Abrasive, carborundum roller cylindrical mill of 100kg per hour capacity, run by 1.5kW electric motor is readily available in the market. It has been developed for dehusking and splitting of food legumes viz.pigeon pea gram and black gram. It consisted mainly of a 300mm diameter cylindrical emery coated roller to give 13.5 to 14m/s speed at 850-900rpm and dal (splits) recovery rate of 74 to 75%. Though the unit is similar to traditional miller machine and gives more or less the same dal recovery, it is useful for small scale production (8 to 10q per day) of dal in villages & towns.

  ii. Cylinder concave dehuller: This machine has been developed by GB Pant University of Agriculture and Technology, Pantnager. It consists of a 380mm long and 220mm diameter cylinder with trunketed surface, and a concave. The kernels are fed to the unit along the full length of the cylinder. A similar machine developed at IARI, New Delhi has cylinder concave set consisting of 150mm diameter mild steel pipe of 6mm thickness coated with 36 week emery cloth to form a cylinder. The concave has 1x1mm grooves along the length and spaced at 25mm apart. The unit runs on 1 H.P. electric motor when operated at 1080rpm (8.48m/s) and gives a soybean dal yield of 85% at 8.69% moisture content (d.b) with 94% hulling efficiency. The energy requirement of unit is 2.15 Wh/kg with a milling capacity of 140kg per hour. These units have been proved to be of high utility value due to higher recovery rates of splits and improved dehusking efficiency.

  iii. Under runner disc (URD) Sheller: The URD sheller (300mm dia, 100mm thick, 900rpm) can be used for milling of bengal gram. It give 83% recovery of splits with 6% brokens. The energy consumption increases with increase in feed rate upto 250kg/h and remains constant (2kW) upto 300kg/h and then decreases.

  The Central Government is giving a big boost towards the development of this industry. It has dereserved " Pulses Milling Sector" from the category of " Small Scale Industries". Hence no license/ permission is required for setting up of a pulse mill. The mills can obtain their raw material supply from any source and there is no price distribution controls on manufactured products.

  Considering the above factors, a model project of an improved dal mill has been prepared with an installed processing capacity of 200 kg/hr operating in a single shift of 8 hr/day for 25 days in a month thus totaling 480 MT/ annum. The capacity of the unit can be suitably changed as per locational requirement. It is hoped that establishment of such dal mill at village/ panchayat level can play a major role in development of the sector by providing much needed processing facility to the villagers and contribution to employment generation.

  Investment Components of an improved dal mill:

  The various investment components are as follows:

  Land and site development:

  The land requirement for establishing a modern pulse milling unit will depend upon whether the unit will be using wet milling or dry milling operations for conditioning the pulses prior to dehusking and splitting operations and the method of drying of the soaked grain pulses. Generally 1.00 acre of land is required for establishing an improved pulse milling unit having a processing capacity of 480 MT /annum. The land should be with proper elevation. Low lying areas should be avoided, else proper land filling, compaction and consolidation should be done. Availability of suitable drainage facility, road linkages and communication facility should also be ensured. The layout of the pulse milling plant should be done in a manner that helps in smooth operation of various unit operations in tandem to bring about optimal capacity utilization. Additional area will be required for sundrying of soaked grain legumes. The model tentative cost of land and land development charges has been considered at Rs. 2.75 Lakh ( Rs. 2.00 Lakh being the cost of the land @ Rs. 2.00 Lakh per acre for 1.00 acre and the remaining Rs. 75,000/- being the cost incurred for site development such as construction of fencing, internal roads and drainage system etc.)

  Civil construction:

  The various sub components are as follows:

  1. Raw material store
  2. Finished goods store
  3. Processing area
  4. Office space
  5. Machinery Spare Store
  6. Gunny Bags Store
  7. Panel Board Room
  8. Toilet space
  9. Miscellaneous space (Drying Platform)

  The size and civil cost of these structures depend on the production capacity of the project . The civil structures and estimated cost for the model pulse milling plant is as follows:

  Civil Structures

Technology:

The model unit is based on the versatile dal milling technology developed by Central Food Technology Research Institute (CFTRI), Mysore and the machinery is fabricated under the supervision of the scientists from CFTRI. CFTRI, Mysore besides providing assistance in the establishment of the dal mills also provides need based training programme for successfully running these units.

Plant and Machinery:

The details of the nature and type of plant and machinery, their capacity, power consumption, level of automation varies upon the market needs, nature and type of the end products and the investment capacity of the entrepreneur.

The details of plant and machinery for the model project are as Precleaner-1 No.; Dehuskers-2 Nos.; Grader-2 Nos.; Bucket Elevators-4 Nos.; Aspirators and Blowers-3 Nos.; Control Panels-3 Nos.; Destoner-1 No. and Pedal Mixer -2 Nos. The total cost of plant and machinery has been estimated at Rs. 9.25 Lakh ( inclusive of the cost of electrical motors for driving the machines). The plant and machinery proposed are as per design provided by CFTRI Mysore. All these units are proposed to be arranged in a streamlined layout to give continuity of operation.

Electrical and other items:

The various machines have to be connected to electrical motors of suitable power ratings for supplying power to them. Accordingly AC -3 Phase motors of different power ratings, varying from 2.50 Hp to 7.50 Hp will be required for powering the various unit operations of the dal mill. The total cumulative Hp ratings of all these motors will be in the vicinity of 15.50 Hp. The cost of the electrical motors have been included along with the cost of plant and machinery. However, a cost of Rs. 50,000/- has also been considered for internal wiring and associated electrical work.

Miscellaneous fixed assets:

A cost of Rs. 1.30 Lakh under miscellaneous fixed assets has been considered for meeting the expenses for office furniture, weighing balance/scale, gunny bag sealing machine, office equipment, fixtures, steel ladders and platforms for cleaning of machines and equipment etc.

Utilities:

Power

The total connected load for the aforementioned unit will be in the tune of 15.50 Hp or 11.56 kW. In addition to it power requirement to the tune of 1.00 kW will be required for general lightening. Thus the total power requirement for the model project will to the tune of 12.56 kW. Accordingly a a suitable power connection of 20 KVA is required.

Water

The total water requirement of the unit will be 500 litres per day. Water is mostly required for soaking and for moisture treatment of the grain pulses. Apart from it water is also required for domestic comsumption purpose.

Standby diesel engines, generator sets and other utilities

Suitable standby power arrangement (DG sets of 20 KVA) may be made under the project. Accordingly a cost provision of Rs. 95,000/- has been made.

Provision for fire fighting:

Necessary provision for fire fighting equipment may be made while installing the dal mill. Accordingly a cost provision of Rs. 15,000/- has been made.

Provision for Insurance:

Necessary provision for insurance may be made while installing the dal mill. Accordingly provision for insurance @1% of the original cost of fixed asset has been made.

Contingencies:

A 5% contingency provision is made for unforseen expenses.

Organizational setup:

A minimum of five permanent employees: Two operators, one accountant cum store keeper and two watch and ward person are required for the unit. Besides two skilled and 10 unskilled workers are required under the scheme.

Eligibility of borrowers:

The borrowers can be proprietary and partnership firms, cooperatives, joint stock companies, corporations, APMC boards, growers associations , NGOs, PVOs etc.

Repayment:

The repayment schedule has been calculated considering the tenure of term loan to be 9 years , inclusive of a grace period of 2 years. However, banks are free to decide upon the repayment schedule depending upon the net cash flow statements and availability of adequate coverage to repay the term loan installment.

Interest rates for ultimate borrowers:

Banks are free to decide the rate of interest within the overall RBI guidelines. However, for working out the financial viability and bankability of the model project, we have assumed the rate of interest as 12% p.a.

Interest rate for refinance from NABARD:

As per the circulars issued by NABARD from time to time

Security:

Banks may take a decision as per RBI guidelines

Results of financial analysis are as under:

The financial analysis of the investment on the improved dal mill having an installed capacity of 480 MT/ annum has been attempted and is placed from Annexures I to VII. The project has a margin money component of 25% with the rate of interest on term loan and working capital as 12% p.a. and 13% p.a. respectively. For this project, the financial indicators of the investment are as under:

Net Present Value @ 15% DF (NPW) = Rs. 12.37 lakh

Internal Rate of Return (IRR) = 25.04 %

Benefit Cost Ratio (BCR) = 1.03:1

Average Debt Service coverage Ratio (DSCR) = 1.54:1

Annexures