A Commercial Popcorn Popping Popcorn Popper. We are constructing a 1-liter popcorn popper to be operated in steady flow. First tests in this unit show that 1 liter/min of raw corn feed stream produces 28 liter/min of mixed exit stream. Independent tests show that when raw corn pops its volume goes from 1 to \(31 .\) With this information determine what fraction of raw corn is popped in the unit.

Chemical Reaction Engineering (CRE) is a core study area focused on managing and optimizing chemical reactions to be efficient and cost-effective. It's essential for developing various industrial processes where conversions and transformations happen, such as in a popcorn popper. Despite not being a traditional chemical process, the transformation of raw corn kernels to popped corn applies similar principles.

In CRE, understanding factors like reaction rates, temperature, pressure, and volumetric changes is crucial. For the popcorn popper scenario, the heat provided must be sufficient to trigger the popping — a physical transformation where moisture inside the kernel turns to steam and expands. Different kernels may pop at different rates due to variability in size, moisture content, or even composition, making it a complex system to analyze.

A steady flow process is a key concept in both engineering and physics, referencing a system where the mass and energy flow rates are constant over time. In the context of our popcorn popper, it signifies that there's no accumulation of corn kernels within the popper; the rate at which raw corn kernels are introduced to the system is the same as the rate at which popped and unpopped kernels are ejected.

The importance of a steady flow process lies in its predictability. In industrial settings, maintaining this steady state means equipment can be sized appropriately, and production rates can be determined. For the given popcorn popper example, keeping a steady flow is essential for continuous operation without interruptions or blockages. It's a practical embodiment of dynamic equilibrium in a non-chemical sense.

The essence of a mass balance is to account for the material entering, leaving, and accumulating in a system. It's based on the law of conservation of mass. In a steady-state process like the popcorn popper, the mass entering and leaving the system must be equal since there's no accumulation.

Applying the mass balance equation, the sum of the popped kernels and unpopped kernels should equal the inflow of raw kernels. With volumetric measurements, it assumes constant density for simplification. The ability to balance mass in such situations ensures that the process is in control and predictable, a foundation for further optimization in chemical engineering tasks.

Volume expansion is a physical change that can occur when substances are heated and change phases — demonstrated well by popcorn popping. When heat causes the water within the kernel to convert to steam, pressure builds until the kernel ruptures, leading to a dramatic increase in volume.

Understanding volume expansion is equally necessary for design and operation. The popping process's efficiency is judged by the expansion ratio — the difference between the kernels' initial and expanded volumes. In the popcorn popper’s context, we're examining the change from 1 litre of raw corn to 31 litres once popped, crucial to optimizing the popping process and ensuring a high yield of the desired product.