TVA Fertilizer Research

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    Performance of Dry Fertilizer Applicators
    (1986-12-01) Broder, Michael F.
    The introduction of bulk blending of granular fertilizer in the late 1940s led to the rise of custom bulk spreading and the popularity of spinner spreader trucks in the United States. However, the nonuniform application of fertilizers by spinner spreaders has created an opportunity for liquid fertilizer dealers. In recent years, equipment manufacturers have developed boomed dry spreaders that claim to provide the same accuracy and uniformity as liquid sprayers. This paper presents data comparing the performance of boomed and spinner spreaders, focusing on aspects such as uniformity, rate accuracy, range of application rates, ease of adjustment and calibration, and nutrient application uniformity. The data confirms that no single applicator excels in all aspects of performance. The paper also discusses machine designs, spread patterns, rate accuracy, the effect of speed on rate accuracy, and the segregation tendencies of different applicators.
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    Effect of Granule Size on Application
    (1983-10) Broder, Michael F.; Hubert L. Balay
    This study investigates the effect of granule size on the application of dry fertilizer using spinner spreaders, which are commonly used in the United States for broadcasting fertilizer. Previous research has emphasized the importance of particle size in maintaining uniform distribution within blends. However, the focus has been on smaller particles, discouraging using larger materials. This paper explores the advantages of broadcasting materials larger than typical granular products and examines the impact on spread patterns. The literature review reveals that particle size significantly influences the segregation of raw materials in blends. Small particles travel a shorter distance from the spinning discs than large particles, affecting the distribution pattern. Studies have also shown that irregularly shaped particles travel less distance than spherical particles due to their larger drag coefficients. However, recent research suggests that while median particle size is crucial, size variability has little effect on the spread pattern. The study conducts field spreading tests using a double-spinner spreader and a high-flotation applicator with a single spinner. Three different sizes of urea granules are used, with similar density, shape, and surface roughness. The spread patterns are analyzed using a computer program, and various spinner and chute adjustments are tested to determine the optimal settings. Results demonstrate that larger granules can be broadcasted more effectively when placed nearer to the centers of double spinners. Swath widths increase significantly, with improvements of up to 30 feet observed. The study also reveals that larger granules produce less dust and are less prone to drifting, making them advantageous in reducing environmental concerns.
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    Developments in Fertilizer Technology and Application Techniques
    (1988-12) Broder, Michael F.; Mann, Horace C.; Culp, John E.
    This material provides an overview of the National Fertilizer Development Center (NFDC), a key Tennessee Valley Authority (TVA) program dedicated to fertilizer research and development. Established in 1933, TVA aimed to foster the growth of the Tennessee Valley region and promote public-private cooperation in developmental programs. The NFDC, located in Muscle Shoals, Alabama, is the nation's only comprehensive fertilizer research and development program. The NFDC's primary objectives are to generate new technologies and products related to fertilizers, improve fertilizer use efficiency, and prevent environmental damage caused by fertilizer production and application. The center conducts basic research, developmental activities, and national technology transfer programs in collaboration with the fertilizer industry, land-grant universities, and farmers. It has the necessary facilities to develop and test new technologies, including laboratories, pilot plants, prototype production facilities, and greenhouses. The paper also highlights several recent and ongoing developments in fertilizer manufacturing. One notable innovation is the production of urea-nitric phosphate (UNP), a solid fertilizer with potential economic advantages over traditional methods. The NFDC's falling curtain-evaporative cooling process is also discussed, enabling urea granulation with superior product quality and low energy consumption. Additionally, the use of calcium lignosulfonate as a conditioning agent for granular urea, replacing formaldehyde, is explored due to its environmental safety and cost-effectiveness. The material further outlines advancements in sulfur-coated urea, nitrogen-sulfur fluid fertilizers, and phosphate-based products, including ammonium polyphosphate and urea phosphate. It highlights the NFDC's efforts to develop cost-effective fertilizers while considering environmental concerns and using lower-grade phosphate ores. It concludes by discussing recent progress in fertilizer application technology, including automatic rate controllers and fuel efficiency improvements in custom application equipment.
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    Storage of Suspensions
    (1978) Broder, Michael F.
    This material provides recommendations for storing and sparging suspensions in industrial settings. It emphasizes using vertical tanks of mild steel or plastic equipped with air-sparging capabilities. Tank size, typically around 16,000 gallons with a diameter of 12 feet and a height of 20 feet, is deemed satisfactory. Coating the inside of steel tanks with epoxy-based paint can extend their lifespan. The document discusses the advantages of cone-bottom tanks over flat-bottom tanks in resuspending settled materials. It suggests using a foundation made of well-compacted 1/4-inch crushed rock, gravel, or concrete. Proper drainage is essential to prevent the tank bottom from standing in water. For transferring suspensions into and out of storage, a centrifugal pump with a 5-inch inlet, 4-inch outlet, and a 30-hp motor is recommended. Depending on the circumstances, a more powerful motor may be necessary. The transfer lines should be 4-inch black iron or PVC schedule 80 plastic pipes, adequately supported and equipped with expansion joints. The document provides illustrations for recommended designs of air spargers for both flat-bottom and cone-bottom tanks. Sparging, the process of discharging air into the suspension, is crucial to control gel strength, syneresis, and crystal growth. The material suggests sparging each tank once or twice weekly to manage gel strength and syneresis. To prevent excessive crystal growth, especially near the tank walls, frequent sparging is advised during temperature decrease. Daily sparging is recommended in colder seasons until the suspension reaches a similar temperature as the outside air. Once the daily average air temperature stabilizes or rises, the routine sparging schedule can be resumed. Immediate sparging before the withdrawal of suspension from the tank enhances fluidity and corrects any syneresis that may have occurred. The suspension may freeze to a solid mass in regions with temperatures that are frequently below freezing. However, when the outside temperature remains above 40°F for about a week, the suspension becomes fluid and can be sparged. Heating coils can warm frozen breaks, requiring approximately 40 gallons of fuel oil to fluidize 100 tons of material within the tank. These recommendations aim to ensure optimal storage conditions and control the quality of suspensions used in industrial processes.
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    Quality Control of Liquids and Suspensions
    (1984-12) Hubert L. Balay
    The analysis and quality control of solid fertilizers has been extensively studied. In contrast, liquid and suspension fertilizers have often been assumed to be less prone to quality control issues due to their relatively homogeneous nature. However, control officials' reports indicate that such assumptions are unfounded. This publication investigates the impurities in raw materials, particularly phosphate sources, used in fluid fertilizer production and highlights their contribution to quality control challenges. The study draws upon research conducted by the Tennessee Valley Authority (TVA), revealing the presence of insoluble compounds derived from impurities in phosphate rock and wet-process phosphoric acid production in raw materials used for fluid fertilizer production. A profound understanding of the fundamental principles underlying liquid and suspension fertilizers is crucial to establish an effective quality control program. The publication clarifies the significance of a solubility curve representing the relative solubility of ammonium phosphates during fertilization. Furthermore, it emphasizes the importance of selecting appropriate potash grades for suspensions, considering criteria such as size specifications and impurity content. The publication also provides insights into preparing carriers for suspensions, focusing on the commonly used attapulgite clay as a suspending agent. It highlights the necessity of properly shearing and gelling the clay to prevent settling and crystal growth in suspensions. The recommended shearing process involves multiple passes through a centrifugal pump, ensuring optimal orientation of clay particles. Additionally, the publication explores the electrical charge characteristics of attapulgite clay, which contribute to its ability to prevent solids from settling. Sampling techniques for fluid fertilizers are addressed to ensure accurate chemical analysis. Proper sampling procedures are outlined, including the importance of recirculating the fertilizer through the pump to obtain representative samples. The publication suggests determining the optimal recirculation time experimentally or with assistance from control officials, ensuring reliable and consistent sampling.