Energy utilisation in rural industries in Karnataka
Ramachandra T.V.
Energy and Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Science, Bangalore - 560 012.

Case Study: Energy studies in cashew processing industries

Objectives of the study.
The objectives were to:

  • Explore the relationship between the energy consumed and production in rural industries based on the data collected from the rural industries.
  • Identify the patterns, type and efficiency of energy use in the rural industries, particularly in its more energy intensive processes such as heating.
  • Study ecological perspectives of rural industries.
  • Identify technical measures for improving energy efficiency.

The study was carried out in five stages:

  1. Initial information was collected from the Government agencies such as the Department of Industries, Directorate of Economics & Statistics and Districts Industries Centres; regarding many cashew industries in Karnataka.
  1. A questionnaire-based survey covering firms and units in the Cashew processing industry sector was conducted in Kumta taluk of Uttara Kannada district (of Karnataka State, India) to determine the levels and patterns of energy consumption and the technologies in use.
  1. Brief (one to two days) energy audits, management and employees interviews were conducted in representative firms to check and cross verify the data collected from the secondary sources and to identify opportunities for energy efficiency improvements.
  1. Computation of Specific Energy Consumption (SEC) and Energy Intensity (EI) to find out the level of disparities among firms.
  1. Establishment of quantitative relationship among various parameters such as Energy (En), Production (Pr), Specific Energy Consumption (SEC) and Percentage [percentage installed] Production Capacity Utilisation (PPCU).

Study Area.
The primary survey was carried out in industries located in the Kumta taluk of Uttara Kannada district. Kumta taluk is located in the coastal tract of Karnataka [7]. It lies between 74° 24' to 74° 45' east longitude and 14° 17' to 14° 35' north latitude and extends over an area of 582 square kilometres. With a population of 107,963, Kumta taluk is one of the densely populated regions in Karnataka.

Cashew Industries.
Cashew processing industries were selected for this study mainly because:

  1. The processing industry being mainly located in the rural areas depends on local raw materials, tends to rely on local resources for heat energy needed, and employs local youth. 85% of the labourers are women. Rural women, who form the major labour force, also endure the burden of domestic drudgery.
  1. Fuelwood is used as main source of heat energy in the processing. The quantity of fuelwood required and its impact on the environment is enormous. The rising cost of fuelwood and scarcity of fuelwood has forced industrial entrepreneurs to think in terms of better processing devices e.g. boilers, improved driers as well as growing fuel wood in the indigenous way.
  1. The raw material required for the industry could be grown on the barren and already degraded land, unfit for habitation or tillage. The crop does not require any fertilizer or pesticide application or even nursing.
  1. Cashew growing provides employment to rural youth.
  1. Cashew growing helps in restoring the soil condition.
  1. The industry is labour intensive (and helps with rural employment generation), the raw materials are processed by hand which helps in yielding better quality nuts.

The main function of the cashew processing industry is the recovery of the kernel from raw nuts by manual or mechanical means. Processing consists of moisture conditioning, roasting, shelling, drying, peeling, grading and packing. The present study covers 142 sample industries from all districts in Karnataka. Also detailed investigations of processing were carried out for ten industries in Kumta taluk of the Uttara Kannada (North Kanara) district of Karnataka.

Some of these processes are illustrated in the flow diagram on the next page and all terms are explained in the text, which follows.

Conditioning: Conditioning involves sprinkling of water on dried and stored nuts to bring them to an optimum moisture level of 20% - 30%. To make the shell brittle, roasting is done. The mesocarp of the shell consists of honeycomb like cells containing a viscous liquid called the cashew nut shell liquid (CNSL), which provides natural protection to the kernel against insects. CNSL is a valuable raw material for some polymer-based industries such as paints, varnishes, resins and brake linings. Industries in Kumta export and sell these shells to Goa and Ankola where boat manufacturers use the CNSL as paint.

Roasting: Drum roasting is done in most of the industries. The capacity of the drum is 320 kg. Shells are roasted in steam at 100°C, for about 22 minutes. In most of the industries during the course of our survey, workers were instructed to load nuts to the full installed capacity of the drum. The nuts are kept aside for a day for cooling. Then Shelling is done using hand and leg operated shelling machines. For this purpose female labourers are employed. Normally a worker shells 17 kg/day. The wages paid on pro rata basis at the rate of Rs. 1.5/kg plus Rs. 1.5 towards transport allowance.

One sample industry surveyed had 12 female workers in this section. Most of these workers were in the age group from 15 to 25. The kernel is scooped out by means of a sharp needle. After shelling the kernels are dried in the drier to reduce the moisture (approximately 10%) and to loosen the adhering testa. After drying for 8 - 12 hours the peeling is done by hand, using a knife. 25 female workers were employed in this section. A minimum of 8 kg of kernels is given in the morning for peeling per person, which has to be completed and the same quantity is to be returned, when the worker leaves the work place. Workers were paid on the pro rata basis at the rate of Rs. 1.5/kg to Rs. 2/kg.

The next stage is grading of kernels, depending on the specification for exportable grades. The wholes are size graded based on the number of kernels per pound as W320, W240, W210 and W180 (means 180 kernels/pound). Damaged kernels were graded as TH C/2 size), KH (1/2 TH), LWP (small size) SWP & SSP respectively. This grading is done by the experienced female labourers who were paid Rs. 300 - Rs. 400 per month.

Packing is usually done in a tin, which holds 11 kg 340 gms Net, which are subsequently evacuated and filled with carbon dioxide. A rehumidification process is introduced before packing to overcome the possible overdrying. This whole operation has a higher yield rate of 90 to 95% of wholes. The raw materials required for these industries can be grown locally. In the next section cashew plantations are discussed from an ecological perspective in order to assess their ecological viability.

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