The purpose of this model is to simulate the industrial frying of food products, for example potato or corn chips. A schematic of continuous frying operation is shown below.
In order to fry the chips a certain amount of oil circulates through a heat exchanger, and make up oil is added to recover the oil that is lost in the product. The potato chips (or any other food product) will be modeled in SPD components in terms of their solids, water, and oil content. The user specifies the water and the oil component in the material balance tab and everything else in the product stream is consider to belong to “solids”. The fried product contains significantly lower amount of water than the raw product as part of the water contained in the food evaporates.
There are 2 options available for the material balance. The user can either set the oil and water content of the product, or let that be calculated through a built in model as described in the Material Balance Tab. If the user chooses the built in model the moisture loss is calculated by the following equation:
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eq. (A.340) |
where Waterin and Waterout are the water mass fractions in the input and output product streams, respectively, t is the residence time in the fryer (specified by the user) and A, B, C, D, and E, are user specified model parameters. The oil-uptake by the product is calculated by:
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eq. (A.341) |
where Oilout is the mass fraction of the oil component in the output product stream (fried product) and F is a user-specified factor.
There are two options for the energy balance. The user can either set the outlet temperature (of product and recirculating oil) and let the heat transfer efficiency be calculated by the program, or set the heat transfer efficiency and let this outlet temperature be calculated. The recirculation rate, and the inlet oil temperature (that is the temperature of the oil after it goes through the heat exchanger) needs to be specified by the user.
If the equipment size option is in Design Mode and the operating throughput exceeds the maximum throughput, then, the program assumes multiple, identical units operating in parallel with an operating throughput of less than the maximum. If the equipment size option is in Rating Mode and the operating throughput exceeds the rated throughput of the step (which is equal to the rated throughput of each unit times the number of units), a warning message is displayed advising the user to increase the number of units or reduce the operating throughput.
The interface of this operation has the following tabs:
● Oper. Cond’s, see Frying: Oper. Conds Tab
● Material Balance, see Frying: Material Balance Tab
● Utilities, see Throughput Operations: Utilities Tab
● Labor, etc, see Operations Dialog: Labor etc. Tab
● Description, see Operations Dialog: Description Tab
● Batch Sheet, see Operations Dialog: Batch Sheet Tab
● Scheduling, see Operations Dialog: Scheduling Tab
