The following article was featured in the Sept/Oct issue of “Fertilizer International.”
More Than An Equipment Company
As a pioneer in rotary drying technology, Feeco International was founded in 1951 to supply the fertilizer industry and a variety of companies in the chemical processing, mining, energy and paper sectors with a range of handling and processing equipment that add value to the raw materials and basic products. Feeco’s roots in fertilizers are reflected by the acronym of its name: Feeco stands for Fertilizer Engineering and Equipment Company. During the past 60 years, the company has helped solve fertilizer manufacturing problems in more than 700 fertilizer plants around the world. Feeco’s business today embraces the following core areas:
• Testing facilities
The Feeco core values apply to each business sector. The company’s team of engineers can design tailor-made solutions for each customer from start to finish, running laboratory tests, developing and enhancing processes, designing, building and installing equipment, as well as providing ongoing customer back-up services. The skills-sets of Feeco’s engineers embrace mechanical, electrical, structural and chemical engineering. The chain of process design, research and optimisation involves laboratory material testing and 3D design software that allows the visualisation of the equipment to be employed. Feeco can undertake the provision of turnkey plants or single items of equipment, ensuring productivity improvements in the equipment and processes, seeing the project through from installation to start-up, and assuring emergency assistance, field support, training, maintenance and the provision of spare parts. Dan Madigan, President of Feeco International said: “We are more than an equipment company…we’re a complete solutions provider.” One of the company’s particular strengths is the commitment of the Feeco staff. “Feeco has been successful because of the employees that work here,“ Dan Madigan added. “Our average employee has worked for over 20 years at Feeco. This provides us with a lot of knowledge that we pass on to our customers… Whether it is a new or existing process, we can design, lay out, supply and commission your new plant or optimise your existing plant.” The Feeco Equipment line includes:
• Thermal processing
• Granular fertilizers
• Process systems
• Material handling
Within the Thermal Processing sector, Feeco enjoys particular expertise in designing and installing rotary driers. The rotary dryer is an integral part of many fertilizer plants, notably in the production of DAP, MAP, TSP, ammonium sulphate and NPK fertilizers, providing a key element in the quality of the final product. The rotary dryer is a type of industrial dryer that is employed to reduce or minimise the moisture content of the material by bringing it into direct contact with heated gas. The dryer is made up of a large, rotating cylindrical tube, usually supported by concrete columns or steel beams. The dryer slopes slightly so that the discharge end is lower than the material feed end in order to convey the material through the dryer under gravity. (Fig. 1)
Material to be dried enters the higher end of the dryer, and as the dryer rotates, the material is lifted up by a series of internal fins lining the inner wall of the dryer. When the material gets high enough to roll back off the fins, it falls back down to the bottom of the dryer, passing through the hot air stream as it falls. This air stream can be either forward moving towards the discharge end from the feed end (known as a co-current rotary dryer), or towards the feed end from the discharge end (known as a counter-current dryer). (Fig. 2)
In co-current rotary dryers, the heated drying air flows in the same direction as the product, and in the counter-current rotary models, the drying airflow travels against the flow of the product. The rotary dryers directly expose the product to hot air produced by the heat source. As the drum rotates, lifting flights mounted on the inside of the drum tumble, slide, lift and shower the material into the air stream. Lifting flights are carefully designed to accommodate the material being dried and ensure that the product is uniformly exposed. The agitation ultimately leads to higher efficiencies and reduces processing times compared with stationary units. A process that takes an hour in a stationary furnace takes just a few minutes in rotary dryer.
Rotary dryers may be either direct-fired or indirectly fired. Depending on the circumstances, indirect-fired dryers can have several advantages over direct-fired rotary dryers. An indirect-fired rotary dryer can have an internal environment that is relatively free of oxygen through well-designed sealing mechanisms. Such systems can process combustible solids at elevated temperatures with a reduced risk of combustion or explosion.
Feeco is one of the leading suppliers of drying equipment to the international fertilizer industry. What are the criteria in the selection of a rotary drying installation? The first variable in the equation is the percentage of moisture that the material holds in its basic or “raw” state, or the state at which it will go into the dryer. Similarly, it is necessary to know the percentage of moisture desired in the end product, also called the “outlet moisture”. The difference between actual and desired percentage moisture in part determines the design of the dryer.
These factors specifically determine whether a low or high inlet temperature is required, short or long residence times, and counter-current or co-current flow. Before the customer reaches any decision on the most suitable equipment to meet their drying needs, Feeco offers several complimentary services up front:
• Process design program: Feeco’s computerized design program can determine the best rotary dryer for the application.
• Automated drawing program: Based on the above data, Feeco engineers can create a general arrangement drawing of the customer’s rotary dryer installation in Auto CAD. This provides very useful information at the initial stage of the overall plant design, helping to determine whether the drying unit will fit into an existing space or how much space a new plant will require.
• Computer costing program: Feeco’s sales team can then calculate the approximate cost of the system. Feeco has pioneered many innovations in drying/cooling technology. One recent development has been a combination rotary dryer/cooler. This highly versatile product combines the drying and cooling functions in a single installation, using injected air in the fluidised cooling hood (discharge breeching) to produce a fluidising action on the material. This proven design can help solve problems encountered with installing a drying/cooling system in an existing space or building. The cooling hood section can be retrofitted to Feeco and other makes of rotary dryers.
GRANULAR FERTILIZER SPECIALISTS
Feeco offers fertilizer solutions in the following three categories:
Inorganic fertilizers represent the classic approach to manufacturing fertilizers, using inorganic raw materials such as sulphuric acid, phosphoric acid, ammonia, potash and phosphate rock. Feeco’s organic production technology utilises biowaste to create a granular fertilizer product. Other inorganic raw materials can be added to increase the plant nutrition value. Waste-to-fertilizer is an increasingly important sector, whereby many industry processes create raw materials with nutritional value that can be converted to a granular fertilizer.
Feeco’s inorganic fertilizer granulation process has been progressively refined over the years and the company today offers two basic types of granulation systems:
• Tumble-growth granulation
• Pressure granulation.
The choice of optimum process will depend on the raw materials and product requirements. The tumble-growth granulation system is the classical system, using a rotary drum or pelletising disc to form the granules, followed by a drying, screening and recycle circuit. This system is very flexible and allows the use of liquid raw materials, including sulphuric acid, phosphoric acid, ammonia, etc., and reactions of materials to form granules. Pressure granulation systems consist of a double roll compactor to make sheets of the material, followed by a crusher and granulator to break the sheet up into fertilizer size pieces, screening and recycle. The process does not typically require the addition of liquids or the need to dry. Feeco International installed its first NPK granulation unit in 1953. Since then, it has been able to stay in the forefront of granular fertilizer technology by working very closely with both equipment suppliers and customers throughout the world. Feeco has also played in leading role in the development of pipe reactor technology, which has significantly reduced energy consumption and cut unit production costs in the manufacture of DAP, MAP and AS. Feeco can retrofit pipe reactor technology into an existing granular fertilizer plant, starting with a review of all existing equipment, servicing pumps, meters and fluid lines. The Feeco pipe reactor utilises the heat from reactions to remove moisture from the product. The revamped energyefficient plant could save up to 30% in DAP production costs and 90% in MAP production costs. Other benefits include a lower recycle rate, better product, more uniformly sized granules, less dust and a better chemical analysis.
Feeco International’s sister company, Feeco BioSystems Inc., is the industry leader in the design of plants and production machinery for converting biowaste and other organic products into a value-added fertilizer product. Chicken manure, slurry and municipal sewage are among the raw materials that can be transformed into a fortified granular fertilizer. The enriched fertilizers produced by the Feeco BioSystems process do not produce offensive odours during production or application. During production, odour-forming compounds such as sulphur and ammonia are locked out as a result of the chemical reactions inside the enclosed reactor unit. Before discharge into the atmosphere, airborne particles and dust are removed and recycled into the product. The temperatures generated in the chemical reaction and dryer ensure that organic fertilizers produced by the Feeco BioSystems process are entirely free of the micro-organisms and pathogens found in industrial and municipal sludges. The end-product quality far exceeds US Federal Class A disposal stipulations.
Feeco’s waste-to-fertilizer granulation technology has found numerous applications, and the company has provided systems and equipment to convert waste products to a marketable, granular fertilizer. For dust, liquid or filter cake that contains fertilizer chemicals, Feeco offers the proper testing and/or tolling to help define a custom system. One common application is ammonium sulphate, which is generated in nickel refineries, flue gas desulphurisation in coal-fired power stations, and caprolactam production used to make nylon. In some cases, Feeco has applied the compaction method to create granular fertilizer, while other examples have used pelletising disc or rotary drum technology. Dan Madigan is proud of Feeco’s leading role in this field. “What the world today calls waste, to Feeco International, they are just raw materials for products that haven’t been invented yet,” he says. Finding solutions is steeped in the Feeco International corporate DNA. Dan Madigan had earlier paid tribute to the commitment of all Feeco’s staff. The staff themselves confirm this. Thus, Nick Reckinger, Sales Engineer, said: “It’s been very exciting to work on a number of different projects that I can get very passionate about…and know that my contribution to the projects will really be making a difference.” Erik Olson, IT & Marketing Manager, is also inspired by the Feeco business philosophy. “Our solutions are all based around an eco-centrist philosophy, providing a balance between what is needed in the marketplace and what is best for the environment.”
For more information on FEECO’s fertilizer granulation capabilities, Contact us today!
See our fertilizer granulation page.