Manufacturing Process
Harvesting
Trees will be harvested from several different locations in Hawaii, including Pahala, the Waiakea Timber Management Area (State DLNR), and the Hamakua Coast. Loggers will use state-of-the-art equipment to safely remove the trees with minimal impact on the ground. The trees will be cut by machines known as harvesters or processors that will grab the tree by the trunk, cut it from the stump, and strip the branches.
The machine operator sits inside a cab and uses a joystick to operate the machine. An on-board computer calculates the best places to cut the tree for optimal recovery.
The branches are left on the ground to return nutrients to the soils as they decompose. The harvesting machines run on large tracks that travel over the cut and stripped branches to minimize soil damage (compaction).
Eucalyptus requires careful handling to minimize checking (cracking), so the ability to gently lay the logs down instead of letting them just fall helps to ensure high quality. The logs are then gathered by another machine that loads them onto a truck for transport to the mill. Because the logs do not come into contact with the mud, and the trucks will drive on paved or rocked road, (not in the fields), trucks will not be dropping mud on the roads like the old sugar trucks. In areas with invasive coqui frogs, a hot water wash process will be used to ensure the logs and the trucks do not transport the coquis. The log trucks will use the existing network of old sugar road to the extent possible to reduce on-highway traffic.
On arrival at the mill, the logs will be unloaded by an electric crane to a log deck. Depending on the specific characteristics of the logs, they may be debarked and/or put through a conditioning process where moist heat is used to soften them before peeling. After conditioning, the logs are cut to length and sent to a “charger” whose job is to load them into the lathe.
Processing
The Tradewinds Forest Products veneer mill is composed of four major machinery centers: the lathe, the dryers, the boiler, and the turbine. What follows is a description of each of these centers.
The Lathe
The lathe is the heart of the veneer mill. Once logs enter the mill, they are run through the lathe where they are centered and turned against a broad cutting knife which is set at a slight angle. The lathe peels the log, much like unrolling a roll of paper towels, into a ribbon of wood 1/8” thick and as much as 80 feet long in as little as six seconds. The ribbon of wood exits the lathe at approximately 600 feet per minute. The veneer is clipped into 4’ x 8’ sheets (plies), then graded and dried in preparation for shipping for secondary manufacturing.
Our lathe will be manufactured by Raute, a company based in Finland. Raute is widely recognized for the quality of its machines.
The Dryers
The dryers are used to remove moisture from the veneer before shipping. Eucalyptus logs leave the stump with roughly 50% of their weight being water. The dryers will slowly move the plies from one compartment to another at varying degrees of heat until the moisture level is reduced to between 6% and 8%. Reducing the moisture level has three benefits: the plies are ready for our customers to use in plywood or LVL products; the possibility of mold or decay is reduced; and shipping weight is reduced.
Tradewinds’ dryers are being custom manufactured by a company headquartered in Nastola, Finland. The dryers will be constructed in Finland. The dryer infeed and outfeed equipment is manufactured in Vancouver, British Columbia.
Cogeneration
Because power is an important economic factor in manufacturing in Hawaii, Tradewinds has elected to have a 5.5 Mw (megawatt) co-generation facility on site to provide steam and electricity for our veneer plant(a megawatt is a million watts).
The veneer facility will require around three megawatts to operate and the remaining two megawatts will be sold back to the grid to help HELCO meet the green power goals which have been implemented by state government and contribute to Hawaii's goal of energy independence.
The cogeneration facility provides a second benefit to Tradewinds by providing an environmentally sound method of utilizing the veneer mill trimmings and slash from the logging operation.
How does the cogeneration plant work?
Scrap wood from the veneer mill, non-veneer quality logs and other processed biofuels are burned in the boiler to generate high pressure steam. The steam is used to turn a turbine, not unlike the way the wind turns a fan. The rotating steam turbine drives a generator to produce power for operating the mill.
The Boiler
Fans are used to blow air into the boiler to control the combustion and draw combustion gases (flue gas) out of the boiler.
Flue gas from the boiler goes through a series of processes to remove smoke particles, starting with recycling the gas back though the boiler to ensure complete combustion. The next process directs the gases through a “multiclone” which spins the air and forces the medium size particles to fall into a receptacle for collection. Only the fine particles remain.
The next stage of purification is the electrostatic precipitator (ESP). The ESP uses electricity to create a static charge that captures the finest particles. The fine particulates are measured in microns (1/1,000 of an inch in diameter). This process will remove particulates down to 10 microns, one one-hundredth of an inch in diameter. The ash and particulates captured by these processes can be used as soil amendments, road base material or landfill caps. Tradewinds has retained a company from Louisiana to fabricate our boiler. The boiler and turbine working in conjunction with the veneer mill process is the cogeneration portion of the Tradewinds’ facility.
The Turbine
A turbine manufacturer in northern Italy is the supplier of our steam turbine generator.