PO Box 84102       -       Lexington, SC 29073       -       803-957-8694


BIOFUELS - Torrefied Wood

Biomass | Chinese Tallow | Biodiesel | Torrefied Wood

Whetsell Energy is working with the different state power conpanies on testing torrefied wood product. We are in the first stages of setting up a 4 ton per hour Torrefaction plant in South Carolina, to allow the power companies do trial test burns with our products and if they are satified with the results, then long term contracts.


Executive Summary: Torrefaction Facility in South Carolina

As you know, charcoal and making it has been around for many centuries. The process is burning wood with the lack of oxygen. They put wood in piles and covered it with loose dirt. At the start on the industrial revolution and oil had not been discovered yet, men need chemicals to make things. The made wood distillation plants to get the chemicals and the byproduct was charcoal (wood torrefaction). There was many ways of doing this but a man who's name was Stafford and he found a way to make it better and faster. It is call "Stafford Retort Processing". The type of equipment and method employed in wood distillation by the Stafford retort process vary widely from those used in oven carbonization. The major difference is that carbonization is conducted continuously in vertical retorts without auxiliary heat. Wood that has been chipped is used.

The efficient predrying of process wood to low moisture content is necessary for satisfactory operation. Rotary driers heated by the gases from the biomass power plant are used to dry the wood to a moisture content of about 10 percent. The dried material is automatically fed to the retorts in regulated amounts.
 
Pulverized Torrefied Wood Mass

The retorts are about 40 feet high and 40 feet in diameter, and heavily insulated. Provision against heat loss must be made, since proper heat balance within the retort is a controlling factor in the operation. Valves at the top and bottom ends of the retort prevent air from entering with the raw material and also prevent the escape of volatile products. The dried wood is fed to the retort at a temperature of about 200° F. As it moves downward, both its temperature and its rate of carbonization increase. Carbonization is carried on by making use of the heat that is continuously available from added wood undergoing similar change to charcoal. Heat is concentrated at highest temperature in a zone about midpoint of the retort. The average temperature in this zone is about 550° F and gradually decreases to about 480° F at the base .

Volatile materials pass from outlets at the top of the retort to four evenly spaced condensers. The charcoal is discharged continuously to airtight coolers and conditioners in a finely divided form that has limited markets, but with a little grinding is made readily suitable for briquette manufacture.

Now there is a similar process to this is what our company is going to use. It is manufactured by a US based company The wood chips will be dried in a dryer and torrefaction process will be in the torrefaction plant. Our torrefaction plant will operate as described next.
 
Torrefied Wood Mass

We will take biomass wood chips chips with about a 40% water content and weight 15lbs/ft3 from grinders or chippers and brought to us from suppliers. They will be put in a receiving pile. We will also take wood waste from the landfills and forest waste to be run through our grinders and chippers. The material will then be run through our screenimg system to take out everything less than 3/8 inch before the chip dryer. These are what we call fines and it will be used in our biomass boiler. The chips will leave the dryer with about a 10% moisture content. The wood chips will then feed into the turbo-dryer. The torrefied wood chips will leave the turbo-dryer, cooled down and be transported to the power plant. If our plant is build next to the power plant then it would be fed by conveyer with no more transportation cost. The power to heat the turbo-dryer would come from a biomass combustion unit which would also heat the wood chip dryer with its exhaust stack gases. The facility would produce about 250 tons per day.
 
Temperature Attained to Torrefy Wood

The cost to build, start up and maintain this plant would be about $10 million USD. The time to get the permits, property, equipment, construction and brought on line to full production is 12 months or less from the time of funding. There are also many State and federal tax breaks for this type of plant. This plant would create many jobs directly and indirectly in rural areas with high unemployment and create more tax incentive. If a power plant used 1200 tons of coal per day and they had our product, they would be using 20% alternative and renewable energy. This could be pelletize and shipped to Europe and sold at a higher price. It would also be used in a conventional coal fired plant with very little modifying. Just a mixing system before it goes into the Hammer mills to be fed into the burners.