Some issues about using wood pellets for power generation

As is known to us, electric is extremely important to the society, it has close relation to the human, recently, as the development of our society and the fast improvement of technology, let along the rapid increase of electronic products, electric becomes one of the most important necessities of life. Without electric, people cannot warm themselves, watch films, using machines and so on; consequently, electric power plants are necessary all over the world. In this case, what power can produce electricity? Traditionally, thermal power is the representative of conventional energy for electricity generation, but recent years, as the fast development of technology and the pollution of environment, wood pellets for power generation has played an important role in electricity power plants all over the world.
Conventional energy for power generation—thermal power


Thermal power is a typical example of conventional energy for power generation; when it works, it drives the heat which generated by burning coal, petroleum and natural gas into the turbine, through the electrical generator to convert the heat into electric energy. Thermal power is the primary force in electric power development at present stage. The advantages of thermal power are:

• The initial investment is pretty low because the reserves of coal, petroleum and natural gas are relative abundant, and the distribution is very extensive, so it’s easy to exploit and utilize, moreover, it is easy to transport which also can reduce the economic costs.
• The construction period is short due to the support of government; it can be built anywhere, the impact of season and climate is quite small.

But meanwhile, as the fast development of technology, the disadvantages of thermal power increasingly prominent day by day.

• The most important impact is that burning coal, petroleum and natural gas is driving a fast release of much more carbon dioxide which can lead to the increase of greenhouse gas emissions, in this case, the pollution of the environment is serious.
• The later investment is high and there is a high demand in transportation for thermal power plant.

Typical diagram of a coal-fired thermal power station

1. Cooling tower	2. Cooling water pump	3.Transmissionline
4. Step-up transformer	5.Electricalgenerator	6.Low pressure steam turbine
7.Condensatepumps	8.Surface condenser	9.Intermediatepressuresteam turbine
10. Steam Control valve	11.Highpressuresteamturbine	12. Deaerator
13.Feedwaterheater	14. Coal conveyor	15. Coal hopper
16. Coal pulverizer	17. Boiler steam drum	18. Bottom ash hopper
19. Super heater	20.Forceddraught (draft) fan	21.Reheater
22.Combustionair intake	23. Economizer	24. Air preheater
25. Precipitator	26.Induceddraught (draft) fan	27. Flue gas st

Wood pellets for power generation

With the fast-changing development of science and technology, at the same time, the increasing environment consciousness of our society, thermal power plants are phasing out the use of coal, petroleum and natural gas to generate electricity. Instead most of the countries realize wood pellets are more appropriate for power generation. And wood pellets are manufactured into several types and grades as fuels for electric power plants. The reasons are as follows.

• The low moisture content (below 10%) of wood pellets makes it possible to be burned with higher combustion efficiency compared with fossil fuels which can save the costs.
• Research has showed emissions such as carbon dioxide, nitric oxide, sulfur dioxide and so on from wood pellets as fuels of power generation plants are lower than that from fossil fuels such as coal, petroleum and natural gas. This is to a great extent protect the environment and it’s the most prominent advantage in comparison to the thermal power.
• The raw material of wood pellets is some agricultural residues or industry residues such as sawdust, shavings, waste wood, tobacco waste, etc, and these are very easy to gain, so it’s a long term to utilize, and from the previous description we know burning wood pellets release less harmful gas, it’s a clean energy which widely spread all over the world.
• In addition, wood pellets are one of the renewable energy which all the countries are committing to develop.

Current situation of applying wood pellets for electricity generation
At present stage, wood pellets are gradually used as fuels for electricity generation all over the world especially in European countries, for example, in the Netherlands, the UK, Denmark, Sweden and Belgium; wood pellets are generally used in large-scale power generation plants. This is due to the government regulations.  Some of the European countries initiate Green project, they want to use wood pellets to replace coal, petroleum and natural gas for electricity generation. Among these countries, the government of Belgium officially declares the largest wood pellets power plant.  Another predominant country is the United Kingdom, due to the United Kingdom’s Renewable Obligation program; it has implemented the plan of using wood pellets for electricity generation to replace coal, petroleum and natural gas. A few large coal-fired power plants have either changed their past pattern into the new way which utilize wood pellets and coal together for electricity generation or have converted the entire wood pellets for electricity generation. The Drax power plant which is the largest coal-fired power plant in the United Kingdom converted one of its generating units to run on wood pellets in April 2013. And up to 2016, half of its six generating units will be converted.

Wood pellets are popular in the United States, but they are mainly used for heating, and recent years, people have begun to use wood pellets for electricity generation. Furthermore, wood pellets are extremely cost efficient in rural areas which lack of natural gas.

As stated, wood pellets for electricity generation is high-efficiency, although the cost is a little higher than that of thermal power, it’s still cheaper than the impact of carbon dioxide emissions. So wood pellets have a huge potential, and at the same time, wood pellet mill is in great demand, if you are interested in this, Anyang Gemco Energy Machinery Co., Ltd Henan, China will give you some supports.