What does plug flow mean?
What does plug flow mean?
In fluid mechanics, plug flow is a simple model of the velocity profile of a fluid flowing in a pipe. In plug flow, the velocity of the fluid is assumed to be constant across any cross-section of the pipe perpendicular to the axis of the pipe.
What is ideal plug flow?
An ideal plug flow reactor has a fixed residence time: Any fluid (plug) that enters the reactor at time will exit the reactor at time , where is the residence time of the reactor. The residence time distribution function is therefore a Dirac delta function at. .
What is plug flow in wastewater treatment?
A type of flow that occurs in tanks, basins, or reactors when a slug of water or wastewater moves through a tank without dispersing or mixing with the rest of the water or wastewater flowing through the tank.
What is the opposite of plug flow?
Consequently, the output composition is identical to composition of the material inside the reactor, which is a function of residence time and reaction rate. The CSTR is the ideal limit of complete mixing in reactor design, which is the complete opposite of a plug flow reactor (PFR).
What causes plug flow?
Plug flow can be described as a piston flow model. This is because the reaction occurring within differentially thin slugs of fluid fills the entire cross-section of the tube which are separated from one another by hypothetical pistons that prevent axial mixing.
How do you get plug flow?
Theoretically plug flow could be achieved by two methods: a) using a number of CSTRs in series, or b) operating high net flow Reynolds numbers in a tubular reactor. Achieving the ideal plug flow requires an infinite number of CSTRs, which is impossible.
Which is better CSTR or PFR?
A PFR has a higher theoretical efficiency than a CSTR of the same volume. That is, given the same space-time (or residence time), a reaction will proceed to a higher percentage completion in a PFR than in a CSTR. This is not always true for reversible reactions.
What is an ideal CSTR?
An ideal CSTR will exhibit well-defined flow behavior that can be characterized by the reactor’s residence time distribution, or exit age distribution. Not all fluid particles will spend the same amount of time within the reactor.
What is the difference between plug and mixed flow reactor?
In plug flow, the concentration of reactant decreases progressively through the system; in mixed flow, the concentration drops immediately to a low value.
What is activated sludge treatment process?
The activated sludge process is a means of treating both municipal and industrial wastewater. The activated sludge process is a multi-chamber reactor unit that uses highly concentrated microorganisms to degrade organics and remove nutrients from wastewater, producing quality effluent.
Is CSTR a flow reactor?
In flow chemistry, a continuous stirred tank reactor (CSTR) equipped with features to continuously feed and exhaust reactants is an example of a mechanically mixed flow reactor.
How plug flow can be overcome?
What do you need to know about plug flow?
In fluid mechanics, plug flow is a simple model of the velocity profile of a fluid flowing in a pipe. In plug flow, the velocity of the fluid is assumed to be constant across any cross-section of the pipe perpendicular to the axis of the pipe. The plug flow model assumes there is no boundary layer adjacent to the inner wall…
Which is an example of the plug flow model?
The plug flow model has many practical applications. One example is in the design of chemical reactors. Essentially no back mixing is assumed with “plugs” of fluid passing through the reactor.
What does a plug flow reactor look like?
Plug flow, or tubular, reactors consist of a hollow pipe or tube through which reactants flow. Pictured below is a plug flow reactor in the form of a tube wrapped around an acrylic mold which is encased in a tank.
What does plug flow mean in fluid mechanics?
Plug flow. In fluid mechanics, plug flow is a simple model of the velocity profile of a fluid flowing in a pipe.