Textile Processing: Printing, Dyeing, Finishing by J. L. Smith

Contents

Textile Industry
Energy in the textile industry is mostly used in the forms of: electricity, as a common power source for machinery, cooling and temperature control systems, lighting, office equipment, etc.; oil as a fuel for boilers which generate steam; liquified petroleum gas; coal; and city gas. While the significance of energy conservation awareness is relatively easily understood at home, when a program is introduced into a factory to promote it, its thoro!lgh implementation tends to be delayed at an early stage.

Therefore, for its actual course of implementation. it is desired to devise company-wide coordinated measures similar to QC activities at factories. Also, in order to promote energy saving measures efficiently, it is found to be effuctive to separately consider general management techniques for “rational use of energy” and process-specific techniques to be developed in each specialized technical field.

Since energy management is relevant to a wide range of departments within a company, it is necessary to enhance the awareness, improve the knowledge and obtain the participation and cooperation of everybody involved in the production process. Therefore, while it is necessary for engineers and technicians with specialized technical knowledge to play a central role in energy conservation efforts, the implementation of an energy conservation program itself should not be left to a handful of specialists or specialized sections.

Rather, it is desirable to address the task company-wide, for example by setting up an ‘Energy Management Committee’. Due to its nature of operations, the share of lighting in electricity use is relatively high. After the switch from tungsten bulbs to tluorescent lamps achieved considerable electricity savings, electricity-saving fluorescent lamps have been developed and marketed for further improvements, including those capable of reducing electricity use by several percent for the same level of illumination.

In general, the effectiveness of illumination is influenced by various factors, such as the intensity of light source, the reflection coefficient and shape of the reflective fitting (lamp shade), the layout of the room to be illuminated, interior finish, color and the distance from the light source. Therefore, it is important to re-examine whether the light source is utilized in the most efficient way and take electricity saving measures, if necessary, ,such as reducing the number of lamps in use by switching from global lighting to local lighting as much as possible.

The textile industry uses a vast number of relatively small electric motors. Notably, while a conventional machine was driven by a single motor with the generated mechanical power transmitted to various parts of the machine in a collective manner, many modern machines utilize multiple motors with a control board controlling the movement of each motor, which is directly coupled to a machine part to drive it independently from others.

This is also a rationalized feature in terms of energy saving. However, regarding the selection of each motor, emphasis has been placed on mechanical performance, resulting in a motor with an excessive capacity. This leaves considerable room for re-examination from a energy conservation point of view. In the textile industry, electric heating has largely been replaced by other methods (steam, gas heating, or direct or indirect fired heating) for some time in order to achieve cost reductions.

However, since electric heating only requires a small initial investment as a result of convenience and simplicity in equipment constmction, it is still used for small capacity local heating purposes. Therefore, it is desirable to conduct a comparative investigation into alternative heating methods, such as far-infrared radiation heating, high frequency dielectric heating and microwave heating.

Fuels utilized in the textile industry have already gone through a switch-over from coal to oil. More recently, efficient energy use is under investigation, including the revival of coal on the way to a further move from oil to liquefied and city gases, while reflecting various fuel prices.

In selecting fuels, those with good flue gas characteristics in addition to high calorific value and ease of combustion are desired, so that air pollution can be prevented as much as possible. By and large, boilers used in the Japanese textile industry have experienced a change from Lancastrian- or Scotch-type tubular or smoke tube to water-tube boilers. As a result, boiler efficiency has improved from the conventional 60’s to 70’s of percentage points to as high as the 90’s. Since high performance boilers are prone to a rapid growth of scales inside their water tubes, feed water management becomes important. Furthermore, these boilers have small amounts of retained water and high evaporation speeds so that many aspects of t}1eir operation are automated, including feed water and combust on management.

The noted feature of steam use in the textile industry is that the amount of steam involved is not so large but the locations where steam is required are widespread so that steam losses due to heat radiation from steam transportation pipes and pressure drops are considerable. Therefore. for steam transportation over long distances, high pressure and small diameter rather than low pressure and large-diameter piping is desired, with pressure reducing valves placed as necessary to regulate the steam pressure at the point of use, thereby curbing heat losses.