Cost for establishment of natural gas pipe line is 5,00,000 rupees, in that area where SWAMI TEXTILE is situated.
• Gas fired boiler price is around 10,00,000 rupees.
• Life of boiler is 5 to 6 years.
• Maintenance cost for this boiler is around 15000 rupees/year
• Cost of fuel is 55 Rs/liter and it is much higher than that of wood.
So the overall cost for the gas fired boiler is much high. Also it is useful for any industry to invest 10,00,000 Rs just for gas pipe line so gas fired boiler is not suitable for given conditions.
4.5 Sizing of Pipe
Steam is used mechanical power and heat. A bad designed steam distribution system leads to the steam heat loss. A optimum design leads to the best quality of steam at application.
Following points decide the system efficiency and provide solution for the system.
The primary function of pipe is to provide desired quality steam and after usage it is required to convert in to water and supplied back to the boiler. Heat loss in overall distribution arrangement is 3 to 10% ideally. The management of energy can help to reduce the heat loss by providing proper insulation, repairing the leaks and by providing steam taps as well as by providing water treatment.
The losses are :
• Pressure loss.
• Leakages in taps, valves & gauges etc. .
• Bad insulations
Principal factors determine pipe sizing in a steam system:
1. The pressure loss at the boiler should not exceed the 20% of the maximum allowable pressure. This pressure drops consist of—line loss, elbows, valves, etc. Remember, pressure drops are a loss of energy.
2. Steam velocity. Erosion and noise increase with velocity. Reasonable velocities for process steam are 6,000 to 12,000 fpm, but lower pressure heating systems normally have lower velocities. Another consideration is future expansion. Size your lines for the foreseeable future. If ever in doubt, you will have less trouble with oversized lines than with ones that are marginal.
3. Well designed steam taps
4. Insulation of each and every pipe.
5. All steam mains should be properly laid with optimum size and drained and should be air vented.
6. Distribution system should be designed for least pressure drops.
A practical and well-designed distribution system must be placed based on the ideal as well as practical situations to reduce production cost and increase productivity.
4.5.1 Energy Conservation
• Steam piping layout
A good steam distribution system should be consisting of adequately configured, sized and supported. The environment of the system where it is to be placed should be considered for designing the system as larger diameter pipe will lead to less pressure drop and will make lesser noise than the smaller diameter pipe.
The drainage is an important factor. Piping must be designed with required drip legs to provide better condensation to the drainage steam. These drip legs experience two conditions which are normal condition and start up. These both should be considered for designing the pipe lines.
Moisture separators with traps are very critical part of the design. These are used to collect moisture particles. Automatic air vents should be provided at dead end of steam pipes to allow air which cannot be condensate to remove.
• Design consideration for steam pipe sizing
Required steam quality is entirely based on proper sizing of pipeline and design of proper sizing of pipe is based on velocity and pressure drops.
Pipe sizing can be designed from general criteria accepted worldwide based on the quality required for the steam that is superheated, wet or saturated.
Following are the velocities for various types of steams are:
• Superheated 50-70 m/sec
• Saturated 30-40 m/sec
• Wet or Exhaust 20-30 m/sec
Pipes which are not under used should be isolated quickly to eliminate the heat loses. The transmission of steam from source to point of application should be quick and through shortest distance.
• Steam pressure
The steam pressure must be adjusted in relation with the pressure generated and the pressure needed at point of application.
However, while designing, it is required to consider steam distribution pressure at source, or at little high average pressure; if the generation is at high pressure. Distribution the steam at the same pressure that of source has the following advantages:
• Lower steam velocity leads to reduce erosion of pipe and reduces noise.
• It will provide steam with required pressure at point of application.
• Low cost while designing with small diameter pipe.