Experiences of using wood pellet plant in the United States

In the 1970s, the United States undertook the lacking of energy which promoted the first time of development of wood pellet fuel and wood pellet plant. Wood pellet are mainly produced by pellet plant in large scale. Also there are some small scale factories to produce pellet. The raw materials for pellet plants mainly come from furniture process, paper-making factory and other wood waste in the factories; they are like the propane or the natural gas. The energy come from the consumption of wood pellet fuel can replace of the electricity, fuel for fireplace or stoves and the fossil fuel etc. At the same time, various kinds of stoves can use biomass pellet fuel. 

 

In the United States, the branches in the forest, timbers without commercial value, the unqualified wood, the dead wood, the recycled waste timer, logging slash, the diseased trees, the process residues, construction waste wood etc, are all can be used to process wood pellet fuel through the pellet plant. 

 

According to estimate, wood which come from the forest and make wood pellet fuel may meet 10% of energy demand in the United States. It is clear that the wood pellet fuel is a very important renewable resource. Except the waste wood, another type of biomass resource, using of fiber plant is also very significant. But we concerned more to the fast-growing tree, like the cultivation of cross breed poplar of short rotation.  

 

The American consumes a large amount of sawdust briquette and formation fuel from crushing materials. These wood pellet fuel are produced from the compressed wood waste, its size, ash content and moisture content etc are more evenly comparing with the sawdust, wood shavings and the wood fragments. They are suitable for process in the pellet plant. They are easy to burn which is fit for the complicated automatic control system, and the thermal efficiency is up to 83%. The thermal efficiency is so high that it could completely make up the losing energy during processing. In the North American, the sawdust briquette is usually about 1/4 inches, and the size of the crushing material is a little bit large which are mainly used for the boiler as fuel. And the size of briquette fuel is much larger. 

Burning wood pellet fuel is used for heating system firstly. The heating system which used wood pellet fuel can be classified into four types: the micro 1 MW, small 1-5MW, the middle size 5-15MW and the large 15MW. 

 

The Micro burning systems are mainly used for residence or work unit heating. Air or water is heat by burning the wood pellet fuel, and it realizes the circulation through the pipeline. The he simplest way is to directly burn the wood block shape fuel for heating   in the family fireplace. 

 

The typical medium of small burning device is hot water. The burning of wood pellet fuel can be used for driving the air-conditioning system. It has emerged precedent in American, Russia, German and Austria.  

 

The middle size burning devices are usually used for school heating or company heating in the United States. 

The large scale burning device are usually used for forestry process factory, the surrounded other factories can use them as fuel either. For instance, many enterprises in the United States use the wood pellet fuel for producing cement. 

 

 

The extra large type of burning device are usually used for power generation in the United States, the power generation usually produce about 10-20 Megawatt of power generation, some of them are up to 75 Megawatt. The easiest way is to burn the wood pellet fuel combined with the coal, to reduce the air pollution.

 

There were about 60 wood pellet plants in the United States in 2006, but it didn’t supply for export. 

In 2008, the green recycle energy limited company constructed the biggest pellet plant in the world with the annual production capacity of 560000 ton. The raw material for the pellet plant is the north pine and the forest residues. It has begun to export to Belgium and Holland.

According to statistics, in 2014 exports of US wood pellets to the EU increased by 40% compared with the 2013 year, from 3.2 million tons to 4.4 million tons. Thus, the United States became the world's leading exporter of wood biofuels, ahead of Canada. Newly formed company Highland Pellets has announced plans to build a wood pellet manufacturing plant with a capacity of 500,000 tonnes a year. Work at the site in Pine Bluff, Arkansas, is expected to start in October, and first deliveries from the plant are likely to begin in March 2016. The €97m (US$130m) plant, which is the first venture by newly formed Highland Pellets, was announced on 20 Au

 

In the United States, saving for the natural gas or oil, reducing the emission of CO2 and SO2, promoting the utilization of wood pellet fuel greatly, the nation was promoted to build more Pellet Plant one after another. Wood pellet fuel was gradually replaced the traditional fuel for power generation and heating. The government had supply proper subsidies to this green energy, the rising prices of oil and natural gas give the wood pellet plant a strong driving force.

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