Page 90 - Impiantitica industriale

MAIN APPLICATION

operating flow rate through the replacement of The specific geometry of the hydrocylone influenc-
liners with no working liners (called blanks) in es the efficiency of the solid-liquid separation too;
case of lower operating flow rate. in particular, higher efficiency is reached in hydrocy-
clones with lower diameters.
The advantages of the The use of many small diameters hydrocyclones
hydrocyclone desanding operating in parallel, called liners, is the most com-
mon choice, instead of using one large hydrocy-
“technology are definitely clone: with the multi-liners solution even high flow
relevant in the upstream rate streams are treated with a high separation ef-
ficiency.
industry Most common liners are 2 inches diameter size: in
fact they represent the best compromise between
high efficiency and high flow rate.
The hydrocyclone and The separation efficiency is
the efficiency of separation function of the characteristics
parameters “of the involved streams,

the geometry of the hydrocylone
A hydrocyclone has no moving parts, a conical
section is joined to a cylindrical portion which is fit- and the operative conditions.
ted with a tangential inlet and closed by an end A semi-empirical model is
plate with an axially mounted overflow pipe.
needed for the prediction of
solids removal from water
in such a complex system

How to define the most appropriate liner configura-
tion to achieve the best solid-liquid separation per-
formance for a specific stream to be treated?

Cannon Artes gave the answer to this question
starting from the “phenomenon observation” as
scientists do.

The construction of a pilot plant, at Salerno’s prem-
ises, allowed to perform some tests to empirically
determine the parameters to be used in the general
equations, already available in literature.

The project

The project aims at investigating the performance
Figure 1 - Solid-liquid hydrocyclone schematic of a hydrocyclone by experimental tests conducted
representation on a pilot scale plant.
On the basis of the experimental results, a semi-
The fluid is fed tangentially to allow it to spin; the empirical model was developed and validated for
spinning motion generates very strong centrifugal the prediction of solids removal from water as a
forces - about 2000 times higher than gravity - function of operative conditions, inlet solids prop-
which induce the solid and liquid to separate. erties and geometrical hydrocyclone configuration.
The solid-liquid separation occurs due to their dif-
ferent densities: the material of higher density is Sample preparation
thrown against the wall of the hydrocyclone and With reference to produced water applications,
dragged to the underflow (lower section) while the as a solid particles sample, it was used Alumina
ones of smaller density proceed to the overflow Trihydrate which presents properties very simi-
(upper section) forming respectively a free vortex lar to the solids usually separated by solid-liquid
(outer vortex) and a forced vortex (inner vortex). hydrocyclone mainly the specific gravity and di-
mension.
The efficiency of separation is a function of: Samples were prepared by dissolving the mate-
• differential density; rial in water at a concentration of 500 mg/l un-
• bulk-liquid viscosity; der mixing. The material had a specific gravity of
• solid particles distribution. 2.4 g/cm and a median value of the monomo-
3

84 Impiantistica Italiana - Marzo-Aprile 2021