01-06-2012, 11:43 AM
CONVERSION OF WASTE HEAT TO ELECTRICITY
CONVERSION OF WASTE HEAT TO ELECTRICITY.docx (Size: 600.28 KB / Downloads: 137)
INTRODUCTION
Conversation of waste heat means to save waste heat and use it as a renewable source of energy like solar or geothermal energy.
In India fossil fuel are the source of energy that drive the economy.
About 90% of electricity produced from burning fossil fuels like coal , oil and natural gas.
From which 35% are used in various manufacturing process and transportation , whereas remaining 65% is discharged to environment as waste heat and chemical that pollute the environment . so conservation is necessary.
What is waste heat?
Waste heat refers to heat produced by machines, electrical equipment and industrial processes for which no useful application is found, and is regarded as a waste by-product. .
The biggest point sources of waste heat originate from machines such as electrical generators or industrial processes, such as steel or glass production. The burning of transport fuels is a major contribution to waste heat.
Sources of waste heat
The largest proportions of total waste heat are from power stations and vehicle engines.
The largest single sources are power stations and industrial plants such as oil refineries and steelmaking plants.
POWER GENERATION
Boilers are used in various industrial units to convey heat for different process applications. Though boilers can be categorized into different types and have different efficiency levels, the motive of the industry should be to generate the required quantity and quality of steam at minimum cost. An optimum level excess air level should be maintained. The method of return steam condensate to the boiler helps reduce fuel consumption, along with this method various other methods could be applied to minimize the loss of energy.
Steam plays an important part in the chemical plants for process heating and turbine drives. The rising cost of fuel has made it necessary to adopt measures to reduce energy losses in the steam distribution network. The insulation should be kept in good condition, all valves and other parts of the system should be constantly checked. Condensation recovery in the steam system is very important. When steam condenses, it transfers about 75% of the heat content to the process and the remaining is withheld in the condensed water. It is very important to install a good condensate recovery system to collect the condensate from the process.
Refrigeration is done by various methods such as the vapour compression system, absorption system, and the steam jet system. An air conditioning and a refrigeration plant are efficient when all the system components, i.e. the compressor, the condenser, the evaporator, the cooling tower, etc., are working in matching condition. Other than the servicing of the components and their maintenance, care should be taken to ensure that the outdoor air is kept at a minimum.
Most of the industrial processes in and out of plants involve transportation of fluids and the pump is the mechanical equipment that is used to facilitate this movement. It can be operated either through a diesel engine, an electric motor, or a gas or steam turbine. All these consume energy either in the form of electric power or petroleum products like diesel, oil, or gas. The pumps have to be well maintained and under constant supervision.