230 likes | 321 Views
Dynamic Simulation Model for tracking grain lots in an elevator AE 503 Term Project. Maitri Thakur Agricultural and Biosystems Engineering May 2, 2007. Food Traceability. ISO definition
E N D
Dynamic Simulation Model for tracking grain lots in an elevatorAE 503 Term Project Maitri Thakur Agricultural and Biosystems Engineering May 2, 2007
Food Traceability ISO definition Traceability is the “ability to trace the history, application, or location of that which is under consideration.” • A grain of wheat or a truckload • A standard location size (field, farm, or county) • A list of processes that must be identified (pesticide applications or animal welfare)
Food Traceability • Respond to security threats • Respond to food safety problems • Document chain-of-custody • Document production practices (e.g. organic) • Meet consumer desires or social preferences • Provide due diligence for safety/quality assurance • Protect integrity of brand name • Authenticate claims (e.g. Bordeaux wine)
Traceability ? February 2007: Peter Pan Peanut ButterProduct Recall Salmonella Outbreak March 2007: Simply Fresh Fruit Inc. Recall of Fresh Cut Fruit Trays:Possible Salmonella Contamination March 2007: Frito-Lay Recall of 2 oz. Bags of Fritos Original Corn Chips:Undeclared Milk and Wheat March 2007: Recall of Pet Foods Manufactured by Menu Foods, Inc.(Melamine found in wheat gluten) September 2006: FDA Warning onSerious Foodborne E.coli Outbreak in Several States Source: Food and Drug Administration
Movement of grains for export in the U.S. Source: U.S. Grains Council
Traceability in Bulk Grain Handling Source C Source A Source B Common Storage Silo Cookies Manufacturing Plant Source: Food and Drug Administration
Problem Statement • Grain lots commingled: • To meet buyer specifications as close as possible and to maximize the profit. • Lot identity is not maintained. • Recent experiences with regulatory issues have introduced a growing need to track product identity • Grain elevators facing the problem of having to segregate their incoming products in batches of different end use quality (e.g. GMO and non-GMO)
Storage Bin- Grain Flow Methods • FIFO – First In, First Out Mass Flow • LIFO – Last In, First Out Funnel Flow • NIFO – Next In, First Out Simultaneous Bin emptying and filling with Funnel Flow Source: Hazardous Occupations Safety Training in Agriculture
Objective The objective of this project is to build a dynamic simulation model that tracks individual grain lots in the outbound load from a grain bin following funnel flow
Grain and Bin Specifications • Shape : Cylindrical, Flat-bottom, Bottom-draw • Diameter (D): 15 feet (4.6 m) • Opening diameter (d) : 30 cm (0.3 m) • Grain : Soybeans • Angle of Repose (Θ) : 35° • Coefficient of friction (c) : 0.3 • Bulk Density (ρ) : 770 Kg/m3
m2 ρgAh m2s m2s h Fc Fc m1 m1s m1s m1g x d D Grain Forces
Differential Equations Forces acting on m1: m1g + ρgAh – Fc - Fc=m1d2x/dt2 ……. (1) where, m1 = Mass of load 1 g = Acceleration due to Gravity ρ = Bulk Density of Grain A = Surface area of mass m2 h = Height of mass m2 Fc = Frictional Force = cdx/dt c = Coefficient of friction of grain x = Displacement of mass m1
Differential Equations dm1/dt = ρAdx/dt……. (2) Σ Q = -dm1/dt + 2*dm1s/dt + dm2/dt = 0 dm2/dt = dm1/dt – 2*dm1s/dt ……. (3) m1s: f (c, dx/dt, Θ) m1s = k*(cdx/dt)*cos Θ k = 10
Differential Equations c1 = m1/(m1+m2) ……. (4) c2 = m2/(m1+m2) ……. (5) where, c1 = Proportion of mass m1 in outbound load c2 = Proportion of mass m2 in outbound load
Model Inputs and Outputs • Inputs • Mass of load 1 (m1) • Mass of load 2 (m2) • Outputs • Proportion of load 1 in outbound load (c1) • Proportion of load 2 in outbound load (c2)
Inputs 1. m1 = 2000 bu and m2 = 2000 bu 2. m1 = 2000 bu and m2 = 1000 bu 3. m1 = 2000 bu and m2 = 500 bu
Results m1 = 2000 bu, m2 = 2000 bu
Results m1 = 2000 bu, m2 = 1000 bu
Results m1 = 2000 bu, m2 = 500 bu
Conclusions • Proportions of loads m1 and m2 in the outbound load can be determined at any given time • At t = 0: Proportion of m1 = 1 and Proportion of m2 = 0 • Proportion of m1 decreases and m2 increases with increasing time (FUNNEL FLOW). • As m2 empties out, proportion of m1 starts increasing exponentially till it reaches an equilibrium value • Profiles of c1 and c2 vary depending on m1 and m2
Further Development • More grain loads • Experimental determination of flow dynamics – Relation with Angle of Repose • Model applicable for different grains • LIFO (Real world application) • Simultaneous filling and emptying
Thank you for your attention ! Questions