For many years, inadequate material handling has cost production companies enormous amounts of money. During those same years, equipment suppliers looked primarily at establishing or bidding the “lowest price” proposals and have disregarded the after start-up “cost” to the end user. It wasn’t until the mid-1990s that some of these companies started looking in earnest for solutions to this long-term problem. With that in mind, Ken Simard, president of Nature’s Earth, began the process of researching and fine tuning the manufacture of wood pellet products, which range from Feline Pine cat litter and Equine Pine Horse Bedding, to high grade wood fuel for commercial and residential applications.
Founded in 1992 in West Palm Beach, Fla., Nature’s Earth Products Inc. has become a successful leader in the wood pelleting industry with its product, Freedom Fuel.
In 2007, Simard decided to expand the company into new markets with higher production capabilities, and began construction of a new pellet plant in Laurinburg, N.C. Cliff Bragg, an expert in the pellet business, was brought on board to lend his experience in plant operation, layout and working relationships with other industry leaders. Bragg previously worked with Hamer Pellet Fuel in West Virginia.
Both Simard and Bragg knew what production problems they wanted to solve and what the results would be if they could control normal material handling problems such as receiving, storing, reclaiming, transporting and preproduction processing. Understanding the significance in “price vs. cost” they also were looking for someone to pull together the talents and experience of industry leader companies.
The plant started production on Dec. 19, 2009, and many industry leaders consider it the most streamlined, efficiently designed plant they have seen in recent years.
Some considerations that went into the plant’s planning and construction process included:
- Plant location
- Access of highways, rail, water shipping
- Tax incentives
- Port access
- Special local incentive packages
- Available labor
- Reliable long-term raw material suppliers
- Outside consulting
- Available equipment suppliers
- Engineering firms in the area
- Market expansion and change capabilities
- Production expansion and product changes
- Manual vs. automated material handling
Material handling is one of the most important issues when developing your process solution, but it is probably the most overlooked part of the production process and is often given the least amount of time and consideration.
At the Nature’s Earth Pellet plant, Simard and Bragg brought in the help of Chuck Limbach, who has more than 30 years of experience in the wood pelleting industry. Jason Kessler, of Kesco Inc. in Fort Mill, S.C., also joined the team for plant design and equipment selection. He brought with him industry leading companies such as Bliss Industries, Kice Inc., Laidig Systems Inc. and Rapat Corporation. Kesco has a history of being able to bring together experienced and reputable mechanical and electrical contractor services, engineering and equipment supply.
With this expertise, a material silo storage and reclaim system was designed for the plant, which proved to be the most cost effective and environmentally friendly method available. To start the process evaluation, the group selected a Phelps hydraulic truck lift and covered receiver. From the truck receiver, the material is conveyed via a pair of Rapat incline drag conveyors to the screen, and the overs (larger pieces) are separated while the thrus are conveyed to a 140′ high Rapat high capacity bucket elevator designed specifically for wood. The bucket elevator delivers the material into a cross conveyor with a drop in the center of each of the four 30′ x 104′ silos. Each silo is designated for dry material, green material, hardwood or softwood. Each silo also holds approximately 608 tons at 20#/cf. Using the silos for storage means that labor is eliminated and the system is completely automated.
The team knew many production problems would be eliminated if they developed a complete control system from the time the raw material arrived at the plant site until the final product was packaged. The plant is designed for an initial production rate of 120,000 tons/year, with the possibility of doubling the capacity by doubling the number of pellet mills. It cost a small amount over budget to build in the ability to double production in the initial phase.
Team members knew from experience that operating plants with systems where raw materials were received at the plant and handled with front-end loaders were very labor intensive and also eliminated the ability to have complete raw material control. Consequently “price vs. cost” had to be evaluated. Upon conclusion of their study, it was evident that automated materials handling and specific material silo storage and reclaim systems would be the most cost effective, environmentally friendly method available. Another benefit of the silo and Laidig Reclaimer system is the first-in, first-out inventory control and the blending effect the reclaimer has on the material as it is extracted from the silo. Using multiple silos and having the material blending ability is critical in optimizing the downstream wood pelleting process. Additionally, the ability to blend allows a wide range of raw materials to be processed. This results in a broad range of raw material suppliers, as well as greater raw material buying power. Green material can be stored in two of the silos. These silos feed a Rapat drag conveyor that discharges into a rotary drum drier with an Energy Unlimited burner. The dried material is then conveyed to a third silo.
Dual exit augers allow feeding into two pneumatic conveying lines, which feed three hammer milling lines or pellet mill lines. Each exit auger is equipped with a variable speed drive, giving the operator complete material control while providing an even flow to help eliminate power surging of the equipment being fed. The reclaimers assure first-in, first-out inventory control, and a blending of the stored material as it is extracted from the silo. This results in a more consistent product being introduced to other parts of the production process down line. By controlling the material processes, less power is used and the efficiency of the drying (if green material) grinding and pelleting is enhanced. Green material can either be stored in one of the silos, then fed to the drier, or the silo can be by-passed and material blown directly into the Westec drier, then into the dry material silo, where it waits to be reclaimed and conveyed to further process. By controlling materials from the beginning of the process, different blends of hardwoods and softwoods can be more easily controlled going into the final pelleting process.
Raw materials are sent from the storage reclaimers via a Kice pneumatic conveying line to any one of the three WAM metering bins. They then feed the Bliss fine grind hammer mills that reduce the previously stored material to the optimum particle size for producing the highest quality pellets. Each of the Bliss Model E-4430-TFA hammer mills will process 10 tons/hour. Once the sizing is complete, the wood fiber is conveyed directly to the pellet mill conditioner just ahead of each pellet mill. Again, complete raw material control is the key to designing the most cost effective, power efficient production line.
At Nature’s Earth Pellets, this knowledge and philosophy was adhered to with the strictest attention. The design calls for proper amounts and control of air and moisture to enhance the pelleting process, which establishes the most cost effective pelleting production system available in the industry. Controlling the front-end of the process will pay dividends on the back-end through higher capacity, improved quality and extended parts life. The finished, cooled pellets are then transferred from the vertical coolers via vibratory conveyors to temporary storage before they go into the Hamer Packaging system, the most automated bagging lines available. This system is complemented with dual robotic bag stackers and the new MSK hooder, which stretches the wrap and hydraulically drapes it around the pallet of material, totally encapsulating the material. It is now ready for shipment to its destination.
Again, “price vs. cost” enters the picture. The best payoff is to invest in better, more automated equipment up front and you will reap the benefits of having continuous savings that can be realized every year for years to come. It’s an investment that keeps on giving.
At the Nature’s Earth plant, the design also calls for proper amounts and control of air and moisture to enhance the pelleting process, which establishes the most cost effective pelleting production system available in the industry. When the material flow is totally controlled, there will be less pellet die and roll feeder wear. Inadequate feed, air and moisture control will lead to production costs that are out of line and decrease the profitability of the process.
The cooled pellets are metered out of the Bliss Counter Flow through vibratory conveyor/screeners to one of two Kice pneumatic conveying lines. These lines convey the pellets to bulk storage. The pellets are then conveyed through a Puritan Drum Magnet and then de-dusting with a Kice aspirator. The finished product is then automatically weighed and bagged with a Hamer Form, Fill and Seal system. The down-stream packaging system consists of Conveying Industries, two Kawasaki Robotic Palletizers and a MSK Pallet Hooder.
All pneumatic conveying, dust collection and automation is provided by Kice Industries. Kice Engineering ensured that process efficiency, product quality and emissions control were all being addressed as the plant took shape. Maintaining the highest level of quality, at a fair market price, while operating a plant that has a positive impact on the environment is the goal of all suppliers and Nature’s Earth Pellet of North Carolina. The heartbeat of the pneumatic materials handling system is the Kice Inc. power center, where 6 blowers are housed along with the collectors. Dust from any part of the process is captured here, and from the final production point to the packaging process, the Kice system handles the final product and helps control the product integrity. Customer and community satisfaction with the end product is critical to the company’s success.
In conclusion, raw material control and automated handling of the raw material is the answer to this very successful operation. After evaluating failed pellet plants, it is evident that lack of raw material control from arrival at the plant site, all the way through production, is the single processing problem attributing to their failure. Manual control allows too much room for human error, but automated materials handling is a sure way to achieve optimum control.
