Mass Transport in Animals

1 Key excerpts on "Mass Transport in Animals"

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  eBook - ePub

  Biochemical Engineering

  An Introductory Textbook

  • Debabrata Das, Debayan Das(Authors)
  • 2019(Publication Date)
  • Jenny Stanford Publishing

    (Publisher)

  Chapter 9

  Transport Phenomena of Bioprocesses

  Transport phenomena is the study of the movement of different physical quantities in any chemical or biochemical process and consists of the basic principles and laws of transport. It also describes the relations and similarities among different types of transport that may occur in any system. A proper knowledge of transport phenomenon is necessary in order to effectively design and efficiently operate a bioprocess/biochemical plant. The current chapter lists the fundamentals of transport processes that one comes across in the bioprocessing industries. Hence, this topic is important for people from the chemical as well as non-chemical backgrounds. The word “transport phenomenon” in chemical engineering encompasses the subjects of momentum transfer or fluid mechanics, mass and energy, or heat transfer processes:

  •  Momentum transport deals with the transport of momentum in fluids and is also known as fluid dynamics, e.g., blood circulation in body, mixing phenomena in bioreactor.

  •  Energy or heat transport deals with the transport of different forms of energy in a system and is also known as heat transfer, e.g., sterilization of reactor, temperature control in bioreactor.

  •  Mass transport deals with the transport of various chemical species themselves and is also known as mass transfer, e.g., oxygen transport from bubbles to aerobic microorganism.

  At the beginning, the important and fundamental topics of fluid mechanics will be covered, followed by the heat transfer principles and mass-transfer phenomenon. A typical example of fluid mechanics may be the flow of various fluids in conduit and pipes in the biochemical industry. Note that such flows result in significant pressure drop due to friction, and the mathematical expression of such situations is incorporated in the subject of fluid mechanics. Similarly, the cooling or heating of fluids in a fermenter involves the transfer of heat from the system to the fluid within the fermenter or vice versa. Such cases are typical examples of the phenomenon of heat transfer in biochemical industries. An example of mass-transfer process in biochemical process plants or industries is that of the oxygen transport to the media broth (culture) from the atmosphere (air) within the aerobic fermenter. Three different types of physical quantities are used in transport phenomena: scalar (e.g., temperature, pressure, and concentration), vector (e.g., velocity, momentum, and force), and second-order tensor (e.g., stress or momentum flux and velocity gradient).

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