Spinning Mills – How to control the Energy

Energy Control in Spinning Mills

Energy audit is a preliminary activity towards instituting the energy control programmes in an establishment. Energy audit increases awareness of energy related issues among plant personnel, making them more knowledgeable about proper practices that leads to cost reduction. A medium scale splinting mill at Coimbatore has been selected for the study and energy audit has been carried out in a most systematic way. Energy audit has revealed some important factors that affect the efficiency of motors, materials and energy balance and specific energy consumption at various level in that ma The necessity of an information system for better energy conservation practice is One of the important findings of this work. This paper presents the possible methods of energy conservation that have been identified in die spinning operation, humidification and lighting of a spinning mill.
Keywords. Spinning mill, Energy conservation, Motor loading.

INTRODUCTION
The implementation of energy conservation programmes in spinning mills have gained wide acceptance in the background of the rising cast of commercial energy. The three major factors for energy conservation are high capacity utilization, fine tuning of equip­ment and technology upgradatiOn^{t 2}. This paper concentrates on the application of these three concepts to a spinning mill.
The methodology adopted for conducting the detailed energy audit is:
Basic data collecting on (i) list of power consuming equipment, (ii) production capacities of the major equip­ment and (iii) operating parameters.
Measurement of operating parameters of various equip­ments to estimate their operating efficiency.
Analysis of data collected to develop specific energy saving proposals.
Presentation on the findings of the detailed energy audit.
DESCRIPTION OF THE PLANT
The spinning mill considered for the study comes under medium scale category. Some important details of the mill
• Yarn manufacturing is carried Out using stale-of-an textile equipment.
Daily spinning capacity is 10 000 kg of yarn and number of spindles are 45 072.
The mill operates continuously throughout the year.
Major energy sources are electrici ty and high speed diesel (1150).
Break up of the energy consumption per year is as follows.

Generator power production is not separated and the calculations are done on units of energy consumed.
Contract demand with Tarn ilnadu Electricity Board is for 1800 kVA per month.
Major Consumption Points
Ring frames
Humidification plant Winding
Carding
Blow room
Heating lamps
Lighting

Process Flowchart
Figure 1 briefly outlines the various processes involved in the manufacture of yam in the mill.
Energy Audit Processes
Figure 2 shows the energy audit processes carried out in the mill.

The details of the energy audit processes arc:
Classification of machines was carried out from the power rating of the load and type of load for which they are used.
Information about the machines collected includes met hod of power transmission, loading sequence, sources of energy wastage and method of control.
Energy against power rated data was used for the selec­tion of machines for detailed energy audit.
To identify the methods for energy conservation, following points were considered.
(i) alternate to reduce/avoid energy losses
(ii) alternate to reduce down time
(iii) alternate to optimum selection
Necessity of an Information System for Better Energy Conservation Practices
Energy cost is one of the largest component of conversion cost incurred by the spinning mill. At present, energy related data are collected manually in the spinning mills which involves consi­derable amount of lime, cost and possible inaccuracies. Online information, on the other hand_ provides quick. continuous and accurate results, which will be very touch useful in decision making.
DATA ANALYSIS AND RECOMMENDATIONS
Power consumption pattern in the spinning mill is shown in Figure 3.
It shows that spinning is the major power consuming operation and uses 44.83% of total energy. The second largest use of energy (12.67%) is in humidification plant. The heating lamps use 9.54% of the total energy. Carding uses 7.44% of total energy and the share of the winding section is 6.21% of total energy. Drawing, simplex, doubling, lighting and other operations use the remaining energy.
Energy Factors in the Selection of Electric Motors
Choosing a motor for a particular application is based on ninny factors such as the requirements of the driven equipment, service


conditions. motor efficiency and motor power factor. Table 1 and Table 2 show the actual observations of the present work on motor loading in the spinning mill. One of the important observation is that most of the motors were run at partial load conditions.
Figure 4 shows the loading of motors at various departments and how these deviate from SITRA standard (60%-80%) load.
THE MATERIAL AND ENERGY USE
The material and energy used in the spinning mill is shown in Figure 5 and Figure 6. Considerable amount of energy seeing can he done by the reuse of these waste materials. Such usage conserves both energy and resources by reducing the need for buying new raw material and associated processing and transport cost.
Specific energy consumption and cost for each energy consuming
given in Table 3 which shows that ring frames use 1.4852
WilLS of electric energy pro' kilogram. The second Largest consumer
of electric energy is carding with a specific energy consumption
of 0.2088. Specific energy consumption of blow room is 0.1408.
Spindle of ring frames consumes 45% of power. Many manufac­turers have nowadays developed energy saving spindles having less weight and small wharf diameter. it was observed that 10%

to 19% saving of energy is possible by using energy saving spindles Spindle is a high consumer of energy and the effect of the weightor the tape on energy consumption is more. Economics of SITRA energy saving tape with respect to the least expensive laminated synthetic tape is brought out. which shows that the former gives a saving of 41.21% per tape over the latter''.

HUMIDIFICATION PLANT
The summer and winter conditions are the main designing factor for these plants. The supply of air quantity required is worked out considering the adverse condition in summer. In order to save energy in winter and monsoon seasons, fan speed can be reduced and this will maintain the required humidity condition in the department. The outside heat load can also he reduced by roof cooling and insulation of roof.
LIGHTING
Most of the fittings are twin tube lights. The suggestion is to replace conventional copper chokes with energy efficient copper chokes for the identified fluorescent fittings. The estimation of saving is shown in Table 4. .
MOTORS
Automatic Star-delta Connector (ASDC)
When three-phase motor has a star-delta starter, ASDC is fitted to sense the load current and if it is below set value. delta connection of phases is switched back to star. Thus, the phase voltage changes is from 415 V to 230 V. The magnetizing current reduces at lower load and PF is improved leading to energy saving^5.6.
The use of soft start cum energy saver helps to save energy in the following ways.
continuously senses the load
applies voltage automatically in accordance with load factor
supplies energy needed to perform work provides smooth accelerating facilities
A proposal was given to install soft start cum energy saver for the motors in the identified simplex machines.
Yarn production results in a variety of waste materials and the wastage reduction proposals suggested for this mill are:
Good material handling practices.
Educating the workers on the impact of waste on energy (the price of yam and waste).
Demonstration to the workers about waste saving methods.
Dr R Rudramoorthy, Member V S Puratsik, Non-member
A Rajeswaran, Non-member
Dr R Rudramoorthy, V S Puranik and A Pair:swami are wills the Department of Mechanical Engineering, PSG College of Technology, Coimbatore
This paper was presented and discussed al the National Seminar on 'Textile Control Engineering' lield concurrently with the lath National Celneention of Textile Engineers, Coimbatore 10-11.2000.