Renewable energy

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  • Publicado : 12 de mayo de 2010
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Project of Renewable Energy

Biomass system mixed with a co-generation system and the supply of a district heating

Biomass system mixed with a co-generation system and the supply of a district heating
1.- Introduction and purpose of this work In this project of Renewable Energy we are going to use row material from biomass and later we will use this material converted into a turbine gasand a steam turbine formed by a recuperation chamber will produce electrical energy and a district heating system will help us to save energy in a group of houses. 2.- Biomass Defining Biomass: Biomass is the name given to any material which is recently derived from plants that use sunlight to grow. That is plant and animal material such as wood from forests, material left over from agricultural andforestry processes, and organic industrial, human and animal wastes. Sources of Biomass: Biomass comes from a variety of sources which include: • Wood from natural forests and woodlands; • Forestry plantations; • Forestry residues; • Agricultural residues such as straw, animal slurries and green agricultural wastes; • Livestock residues; • Black liquor from paper manufacturing; • Sewage wastes; •Sugar and grain grown to make alcohol for use as a fuel; and • Grains and oil seeds grown for production of biodiesel. Biomass consumption: Biomass fuels consist of three main segments: wood, waste, and alcohol fuels. Wood energy is derived from the following sources: roundwood, used primarily in the

industrial and electric utility sectors; woodfuel, used predominantly in the residential andcommercial sectors; and wood byproducts and wood waste, which are usually used in the industrial sector. Waste energy is derived from the following sources: mass burning of garbage; conversion of garbage to refuse-derived fuel pellets for eventual burning; collection of methane gas from landfills; and burning or anaerobic digestion of wastes. Alcohol fuel in this report refers to ethanol,typically derived from corn and used primarily in the transportation sector.

3.- Co-Generation System We will use the steam turbine plant for the production of electricity energy and calorific energy. The main part of the steam turbine plant are: • The boiler or steam generator: to give the necessary steam for the good operation of the turbine. • The steam turbine: uses the steam energy and gives thenecessary work for move the generator. • The process in opposite pressure or condenser: use for change the steam to liquid water. • The water pump: for drive the water until the generator.

In this picture we show the co-generation systems:

Consider the steam turbine shown in the cycle above. The output power of the turbine at steady flow condition is: N = m1*(h1-h2) + (m1-m2)*(h3-h2) where m is the mass flow of the steam through the turbine and h1, h2 and h3 are specific enthalpy of the steam at inlet respective outlet of the turbine The steam turbine may consists of several stages. Each stage can be described by analyzing the expansion of steam from a higher pressure to a lower pressure. The steam may be wet, dry saturated or superheatedThe steam turbine plant follow The Rankinecycler. If we choose 4 point in the diagram and draw temperature&entropia:

The efficiency of the steam turbines are often described by the isentropic efficiency for expansion process. The presence of water droplets in the steam will reduce the efficiency of the turbine and cause physical erosion of the blades. Therefore the dryness fraction of the steam at the outlet of the turbine should notbe less than 0.9.

4.- District Heating System District heating (less commonly called teleheating) is a system for distributing heat generated in our steam turbine plants. The heat is obtained from the steam turbine plant. The district heating plant can provide higher efficiencies and better pollution control than localized boilers.

In our steam turbine we will use pre-insulated pipes....
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