paraffin wax deposition and fouling

For breakdown and removal to occur some transformation of the
weakness).
weakness the wax deposit breaks down and is removed from the tube
— 67 —
istic random fuctuations in paraffin deositicn and foulinT.
shear forces. In paraffin waxes there exists a solid crystal
in the establishment of regular crystal matrices, that is, time being
wax deposit structure may take place, reducing its resistance to
required for orientation. As the deposition is a rapid process there
is added opportunity for weakness. As a result of cohesion loss or
On breakdo’. and removal of deposits? only strongly held Crystals
responsible for the creation of weak planes in the paraffin wax
surface, leaving a thin granular layer. (The granular layer probably
It was considered possible that some similar transition might be
represents a well oriented matrix of crystals with few planes of
at low temperatures where the wax transformed into a new crystal
transition (section 2.2.2) at temperatures below the melting point.
lubricating layer around them. The deoosit will therefore be most
kerosene solvent will be exuded from the crystals and form a
near a deposition surface after rapid initial deposition, the
deoosits. These weak planes could be formed near the rube waZ
stresses as deposits build up, are probably the main factors
structure.
will ‘cc left on the tube surface, giving rise to the granular
rapid cooling. As regular denser crystal structures are formed
systems and strong structural network than crystals formed under
structure. As sho in section 2.2.2. crystals formed under slow
likely to break where transition has occurred near the tube wall.
cooling were observed to have less tendency to form solvated
causlnf the breakdon ana removal that give rise to the character
The creation of planes of weakness and the increases in shear