Agro Processing Plant Design Questions and Answers

Answer: A

Correct answer: Proximity to the raw material

Fruit and vegetables are bulky, perishable and lose weight in processing, so hauling them any distance costs money and quality alike. Siting the plant near the growing area minimises transport of the heavy raw material and gets it into process while it is fresh; the finished product is lighter, stable and can be carried to market.

Answer: B

Correct answer: The peak arrival rate of raw material

A seasonal crop arrives in a short window and cannot be held back - it must be processed within days of harvest or it is lost. The plant must therefore be sized for the peak arrival rate, which is why such plants stand idle for much of the year and why their utilisation factors look so poor.

Answer: C

Correct answer: Actual output over rated annual output

It measures how much of the installed capacity is actually used over a year. In a seasonal plant it is inevitably low - often 20 to 30 per cent - because the capacity is set by the peak, not the average.

Answer: D

It is the logical description of the process, and the layout drawing that follows is the physical one. Confusing the two leads to layouts that follow the flow sheet's drawing order rather than the material's actual path.

Answer: A

Correct answer: Determine the quantity of every stream

A material balance applies conservation of mass to the process: what goes in must come out as product, by-product or waste. It fixes the quantity of every stream, and everything else follows from it - equipment sizes, utility loads, effluent volumes and yields.

Answer: B

Correct answer: Matching the capacities of successive stages

Line balancing means sizing each stage so that none is much slower than its neighbours. An unbalanced line throughput is set by its slowest stage, so capacity provided anywhere else is capital that earns nothing.

Answer: C

Correct answer: By type of operation, in departments

A process layout groups equipment by kind - all the cutting in one area, all the drying in another. It suits low volumes and a wide product range, since any product can take any route, but the material travels further and work in progress builds up.

Answer: D

Correct answer: Volumes are high and the product range is narrow

A product layout arranges equipment in the sequence the product follows, so material moves in a straight line with little handling. It only pays where volumes are high and the range narrow, because the line is dedicated: change the product and the layout no longer fits.

Answer: A

Correct answer: Separating raw and finished product flows

The essential principle is unidirectional flow: raw material enters at one end, finished product leaves at the other, and the two paths never cross. Where they do cross, contamination will eventually be carried back however careful the cleaning - which is why the separation is designed into the layout rather than managed by procedure.

Answer: B

Crevices, dead legs and horizontal ledges harbour material that cleaning cannot reach, and that material becomes a microbiological reservoir. Drainability and accessibility matter more than the material of construction alone.