Mechanical process engineering

Water Air
Soil             Waste

Process engineering is the engineering science of material transformation.

Mechanical process engineering involves the changes in material properties (e.g. particle size), and composition (concentration), due to mechanical effects.

Introduction to chapter “Mechanical process engineering”

Separation methods: classifying and sorting
Classification is a mechanical separation method for solid compounds. It utilises either, the geometric features (size) or the settling velocities of the individual particles for the separation process. Sorting is a mechanical separation process in which a solid compound containing different material characteristics is divided into fractions with the same material characteristics.
CE 275
     
CE 280
 
Gas flow classification Magnetic separation  
Zigzag sifter to separate solid compounds   Sorting with a drum-type magnetic separator
 
Separation methods: separation in a gravity field
Mechanical process engineering in many cases utilises gravity to separate different phases. Gravity can be used to separate a solid phase off from a fluid.
CE 115
     
CE 587
HM 142
Fundamentals of Sedimentation Dissolved air flotation Separation in sedimentation tanks
Separation of suspensions by sedimentation                                                                                    Removal of solids from raw water using dissolved air flotation                                                        Solid/liquid separation in a sedimentation tank, visualisation of flow conditions
 
Separation methods: separation in a centrifugal force Field
As well as gravity, centrifugal force can also be used as the driving force for phase separation processes. The centrifugal force can be generated either by guiding the flow of the fluid, or by rotating vessels (centrifuges).
CE 282
     
CE 235
 
CE 225
Disc centrifuge                       Gas Cyclone                                 Hydrocyclone
Continuous separation of emulsions                                 Solid separation from gases with a cyclone  Separation of solids from liquids by using a centrifugal force
 
Separation methods: filtration
During filtration, solid particles are separated off by a filter medium from a flowing suspension. Suspensions contain insoluble solids finely distributed in a liquid. Usable filter media are sieves, cloths, papers or bulk solids.                         
CE 116
 
CE 117
 
CE 287
Cake and Depth Filtration      Flow through particle layers    Plate and frame filter press 
Investigation of the basic principles of filtration: Darcy’s equation                        Investigation of the properties of fixed and fluidised beds subjected to liquid flow               Discontinuous cake filtration for separating solids out of suspensions                         
CE 283
 
CE 284
 
CE 286
Drum cell filter   Nutsche Vacuum Filter   Nutsche Pressure Filter
Continuous cake filtration for separating solids out of suspensions                          Discontinuous cake filtration by negative pressure                                                                   Discontinuous cake filtration by positive pressure                                                                  
CE 579
   
Axial steam turbine                
Removal of solids by depth filtration (sand filter)         
Comminution
Comminution alters the particle size and shape and the surfaces of solids. Virtually all solids must be comminuted when being mined or processed.
CE 245
     
 
Ball Mill
Observation of the grinding process with regards to the comminution of solids  
 
Mixing and agglomeration
Mixing is the opposite of separating. The materials being mixed may be gaseous, liquid or solid. Agglomeration is the opposite of comminution. The terms agglomeration, granulation and pelletisation designate the process of particle size enlargement of solids.
CE 320
     
CE 255
 
Stirring Rolling agglomeration
Visualization of flow fields in mixing with the use of different stirrer types       Dish granulator with adjustable rotation speed and angle of inclination
 
Storage and flow of bulk solids
The term “bulk solids” generally refers to materials in the form of collections of single or individual particles.
CE 210
     
CE 200
 
Flow of Bulk Solids from Silos Flow properties of bulk solids
Influence of wall material and angle of inclination of hopper wall on flow profile and outflow time                      Using a ring shear apparatus to plot the shear force curves of bulk solids; basic principle of silo design
 
Fluidised beds and pneumatic transport
A fluidised bed involves two phases: a solid and a fluid (gas or liquid). Pneumatic conveyor systems transport powderous and granular bulk solids by means of a gas flow (mostly air) in pipelines.
CE 220
     
CE 250
 
Fluidised bed formation Pneumatic transport
Investigation of fluidised bed formation of solids in air and water                                                            Upward, pneumatic pressure transport of solids in a vertical transparent pipe section