Contact Video Poster Gallery About WMC Home
SEARCH











Subscribe Quarterly News Letter for latest development & news. Just fill your E-mail Address :
send your artciles



CASE STUDIES- 2

WASTE MINIMISATION CIRCLE CASE STUDY IN RICE MILLS

1. INTRODUCTION TO THE SECTOR:
2. ABOUT THE CIRCLE:
3. PROCESS DESCRIPTION
4. STUDY FOCUS AREA:
5. WASTE MINIMISATION OPPORTUNITIES THAT REDUCED ENVRIONMENTAL LOAD AND ACCRUED ECONOMIC BENEFITS:
6. POLLUTION STATUS BEFORE AND AFTER CP IMPLEMENTATION:





1. INTRODUCTION TO THE SECTOR:

Rice is a staple diet for many families in India and major portion of the arable agricultural land is cultivated for growing paddy in two seasons namely Kharif and Rabi. The major paddy cultivating states in India are Andhra Pradesh, Punjab, Karnataka, Tamilnadu Uttar Pradesh Madhya Pradesh etc. Accordingly the majority of rice mills are located in these states.

The use of rice is in the form of Raw rice & Par boiled rice. Accordingly the mills process paddy to produce one or a combination of both.
2. ABOUT THE CIRCLE:
This case deals with a group of rice mills in Nizamabad district of Andhra Pradesh. The group formed a circle with assistance from M/s Maruti Consultants and guidance from National Productivity Council to adopt waste minimisation (WM) techniques to reduce their energy and water consumption through sharing knowledge and information with each other to improve their productivity.

The average production capacity of the mills is in the range of 40-50 tons per day. The specific consumption of resources like energy, water ,steam are tabulated below:


S No Parameter Quantity/ ton of paddy.
1. Electricity use for raw rice 17-23 KWH
2. Electricity use for parboiled rice 27-35 KWH
3. Water used for parboiled rice 11.1 -1.3 m3
4. Steam use 750 Kg

3. PROCESS DESCRIPTION

Paddy is procured from farmers and stored in yards. The paddy from storage yards is loaded into bins and conveyed through a bucket elevator to paddy cleaner. Air is blown to remove the dust. The paddy so obtained is screened by vibratory screens to remove heavy particles like stones. The cleaned paddy is conveyed through elevators to storage bins.
The cleaned paddy is sent for deshelling or par boiling depending on the product requirement.
2. Installing copper finned tubes in heat exchanger (to generate hot air) replacing MS tubes to increase heat transfer efficiency. The benefits are:
Investment in copper tubes = Rs 0.7 lakhs
Savings = Rs 0.5 lakhs/annum
Pay back period = 1.5 years.
3. Even steam distribution in paddy soaking tanks and even hot air distribution for paddy drying reduced processing time from 10 hours to 7 hours in a day. The benefits arising of 3 hours increased process time availability and reduced steam consumption are as under:

Additional rice processed =600 T/annum. Profits due to increased production = Rs 3.0 lakhs (@0.50Rs/Kg paddy processed)
4. Marking soaking tanks to indicate water level reduces excess consumption as indicated :
Investment for marking tanks = Negligible
Reduction in water consumption = 1200 m3/annum
Savings in pumping cost etc. = Rs 1200 per annum

5. One of the mills in the Circle which was recently started implemented modern electrical distribution system to overcome Voltage fluctuations in supply line to reduce motor burn outs and mill down time. The results of this option are:
Investment = Rs 1.0 lakh
(Including MCB's, wiring , panel control s etc.)

Savings due to reduced motor burn outs etc = Rs 0.5 lakh per annum (profits due to increased production due to reduced down time is not considered).
Pay back period = 2 years
6. Getting servicing of machinery from suppliers/ authorised dealers to avoid frequent breakdowns. The results of implementing these results are:
Investment = Rs 0.2 lakhs/annum
Savings = Rs 1.0 lakhs per annum
Pay back period = about 3 months

For par boiling the cleaned paddy is soaked in hot water for about six hours and then steam is bubbled into soak tank for 15 minutes. After this the water in the soaking tank is drained out as effluent. The paddy containing 25-30 % moisture is dried by hot air (generated by using steam) to bring down the moisture level to 12-13%. This paddy is taken for deshelling.

The cleaned/par-boiled paddy is deshelled to remove husk in a sheller cum husker. The husk is seperated from rice by blowing air directed towards husk yard. The rice free of husk is sent through elevator to vibratory seperator to separate rice from paddy that is not husked. The rice is then conveyed by elevators to polishing machine. After polishing, bran is seperated from rice (including broken rice) by blowing air over the polished rice. The seperated rice is screened in a vibratory screen to remove broken rice and is then manually packed.

4. STUDY FOCUS AREA:

Experience of M/s Maruti Consultants with Rice mills indicated mills use poorly rewound motors, poorly designed electrical distribution system, using modified versions of lancashire boiler with efficiencies as low as 40%.
This information catalysed the units to look at ways and means to reduce energy consumption through mutual discussions through waste minimisation circle.

5. WASTE MINIMISATION OPPORTUNITIES THAT REDUCED ENVRIONMENTAL LOAD AND ACCRUED ECONOMIC BENEFITS:

Based on the waste assessment study the unit identified ways and means to reduce waste. The most significant WM opportunities that are identified and implemented are as follows:
1. Some of the mills installed new boilers with higher efficiency saving energy, discharging less specific pollution load to atmosphere. The benefits of this change are given below:
Investment in new boiler = Rs 8.0 lakhs
Savings = Rs 4.0 lakhs/annum
Pay back period = 2 years.

6. POLLUTION STATUS BEFORE AND AFTER CP IMPLEMENTATION:

The overall comparative results achieved due to this cooperative initiative of sharing know-how and information are given in the following table.
S No Parameter Before CP(per ton of paddy) After CP((per ton of paddy ) % change
1. Production capacity 40 Tons/day 42 tons/day +5
2. Electricity use for raw rice 17-23 KWH 16-20 KWH -10
3. Electricity use for parboiled rice 27-35 KWH 23-29 KWH -15
4. Water used for parboiled rice 1.1 -1.3 m3 1.0 m3 -20
5. Steam used 750 Kg 650 Kg -15
6. Husk used 300 tons 200 tons -13


News Letters| Case Exercises| Technical Case Studies| Achievements| Training| WMC Facilitators
FAQs| Govt. Statement Policies| Presentation-Slides| Information Sources
Home| About WMC| Poster Gallery| Video| Contact |Query/Feedback

Site is best viewable in 800 X 600 resolution