Volume SH 2: Part
1 Pipeline Design for Slurries and Pastes
This part reviews the knowledge
related to the process design of the pipeline itself
a slurry transport system. The part has been written
assuming that either of two basic design paths is followed,
depending on whether the slurry for which the design
is to be completed can be considered a non-settling
suspension or must be treated as a settling slurry.
The emphasis is on frictional pressure loss estimation,
and the use of different flow models for non-settling
slurries. In addition to frictional pressure loss for
settling slurries, the prediction of the limit deposit
velocity for horizontal pipeflow is also discussed.
Volume SH 2: Part
2 Pipeline Design Methods for Settling Slurries
This part provides a step-by-step
calculation procedure for determining the pressure drop,
minimum flow velocity and the optimum operating conditions
for the transport of settling slurries by pipeline. Procedures
for horizontal, vertical and inclined lines are presented
and losses due to pipe fittings are also taken in account.
The optimum values of the design parameters
(e.g., pipe diameter, flow velocity and slurry characteristics)
depend on how these parameters affect the capital and
running costs for the whole pipeline system and on the
effects of likely changes in the operating conditions
under normal operation.
The results obtained using this part are
suitable for feasibility and preliminary design methods.
They also provide a sensible starting point for the
design of full scale tests which are necessary if accurate
design data are required.
The part is being developed further into
software.
Volume SH 2: Part
3 Pipeline Design Methods for Non-Settling Slurries
This part
gives procedures for calculating the total pressure
loss for the pipeflow of non-settling slurries which
may be treated as pseudohomogeneous mixtures. This pressure
loss comprises frictional losses arising from flow through
straight sections of pipe and through various types
of pipe fitting, together with pressure losses (or gains)
arising from changes in pipe elevation. For frictional
loss estimation, both the laminar and turbulent flow
regimes are considered, and methods to predict the point
of laminar flow breakdown for slurries exhibiting different
non-Newtonian behaviour.
Five alternative
flow models are assumed as the starting point for frictional
pressure loss estimation : Newtonian, power law, Bingham
plastic, generalised Bingham plastic (also known as
yield-pseudoplastic) and Casson models. The guide provides
a step-by-step procedure for frictional pressure loss
estimation and provides several detailed worked examples.
Section 3
provides the summarised step-by-step procedure. This
procedure draws on detailed discussion of viscometry
to characterise the slurry flow properties (section
4), the prediction of laminar flow breakdown and estimation
of frictional pressure loss (section 5), the prediction
of frictional pressure loss for flow in smooth or rough
pipe (section 6), and the estimation of frictional pressure
loss for flow through a range of commonly-used pipe
fittings (section 7).
This design
guide has been developed further into software called
PipeDes.
Volume SH 2: Part
4 Pipeline Cleaning Techniques
This part
describes the various techniques and technologies available
for pipe cleaning. Pipes are cleaned internally either
to remove debris and deposits which remain after the
pipe system has been constructed but before the pipework
is used, or to loosen and scour internal pipe surfaces
which become fouled over time by deposits which can
reduce the pipe diameter, so increasing frictional losses
and reducing the flowrate, or to remove fluid material
so that different fluids may be put down the same pipe
without contamination. In the food industry, regular
cleaning-in-place is required for hygiene reasons.
Much of the
available open literature which has been collected so
far pertains to the requirements of the oil industry,
where waxy deposits are often laid down onto internal
pipe surfaces during the flow of crude oil, and which
require regular removal. In this industry, various designs
of "pig" with their associated launch systems
have been developed. Pipeline pigging is also used in
other industries such as water and paint. In addition
to pigging, there are other mechanical devices which
cut and/or scrape material from the pipe wall as the
device moves along the pipe. These devices may be actuated
electrically, hydraulically or pneumatically. High pressure
water jets, or high velocity gas streams laden with
cleaning agent, is also commonly employed to break-up
and remove hardened deposits.
Much of the
open literature on pipeline cleaning is not related
specifically to slurry pipelines. Because of this, the
information contained in this part includes reference
to other pipe cleaning applications. It is considered
that many of the techniques described, together with
the associated equipment, could be readily applied to
slurry systems, although this is not always specifically
stated in the literature.
Volume SH 2: Part
5 Selection and Design of Pipeline Cleaning Systems
The focus
of this part will be on pig clearing systems that are
"In-Process" - i.e. within the processing
plant rather than any offshore or across-land larger
diameter applications. However, where there is information
that is general to slurry lines, it has been included.
The maximum diameter considered will be 8" / 200mm,
although many of the application will still be valid
for larger diameters.
In the middle
of the document is a form of interactive logic diagram
(CD ROM based) to allow users to set up design parameters
for the optimum choice of pig clearing equipment. This
is based on factors ranging from basics such as reasons
for pig clearing the pipeline, through to the detail
of electrical requirements, product data, utilities
calculations, elastomer choice and certification requirements.
To assist
with the build up of the whole design picture, the document
also outlines the Utilities requirements and calculations
for typical systems, plus some tips to ensure potential
problems are designed out of the systems at an early
stage.
To complete
the picture, there are several case studies from the
various pig system suppliers. These concentrate on both
run-of-the-mill applications, such as emulsion paint
applications, up to the greater challenges of high viscosity
and difficult slurries that require attention to minimisation
of particle breakdown, etc.
For the purpose
of this document, the definition of a slurry is any
product having a solids content whilst still being pumpable.
The carrier for the solids can be any type of liquid.
This definition encompasses applications that range
from clay based products, through paints, foodstuffs,
chemicals and pharmaceuticals
