
Kettle Blending

SMB System |
BLENDING
Current industry trends are favoring shorter cycle times and smaller lot
sizes to meet customer demand and keep inventories low. E-commerce and
other market changes have allowed customers be more selective and have
instilled the concept of "instant" availability for almost
everything. The result is ever-increasing pressure on manufacturing facilities
to increase flexibility and become more efficient.
Plants which were designed to produce large quantities of a few items and
are now being asked to produce very small quantities of hundreds of items. In
many cases this presents very real problems; such as increased changeover
frequency and downtime, increased product waste, cross contamination, and
extended working hours, to mention a few. Modification of the physical plant
and batching systems may be the only way to reconcile this growing gap between
changes demand and required manufacturing capability.
As part of a conceptual study, or as a stand-alone project, we can help you
specify the blending system that best meets your needs. Depending on the
products to be blended, the number of blending components, the size of each
batch and the time available to complete each batch, the type of blending
system needed can vary widely. Our approach is to "right-size" the
system for the application.
The process normally begins with a review of the products to be made,
followed by an in-depth analysis of formulations (or recipes), to determine how
each product should be made. The relative concentration of each blending
component in each formulation is considered and a blending system is developed
to accommodate them all. During this process, we keep a number of parameters in
mind including the chemical or physical compatibility of blending components
with each other, the physical limitations of the operator (his ability to lift
heavy hoses, dump 50-pound bags of dry ingredients, etc.), the potential
toxicity of the blending components and issues of batch-to-batch
cross-contamination. We are familiar with all of the blending solutions
available commercially and the advantages offered by each. For most
applications, the best answer lies in a combination of two or more blending
approaches.
The following are brief descriptions of some of the more common blending
methods we can employ.
Conventional Kettle Blending: A
manual operation where all components are weighed or metered into the mixing
vessel for blending. Heating is typically done with steam or hot oil and mixing
is achieved using a mechanical electric-powered agitator or Pulsair system.
Finished blends are normally transferred from the mixing vessel to finished
product tanks, but sometimes the product is filled or packaged directly from
the kettle.
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Conventional Pipeline Blending or Tank
Blending: This method uses "set/stop" meters to introduce
bulk liquid components into a pipeline or header. That, in turn, is piped to a
finished product storage tank. Typically, the meters are manually operated and
the components are mixed in the finished product tank. Heating may be achieved
using tank coils, suction heaters, or external heat exchangers. Agitation
methods include simple air blowing, mechanical mixers, pump circulation (with
eductors), or Pulsair devices.
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Automated Batch Blending (ABB):
An ABB is kettle-type blending system that incorporates automated
delivery of some or all blending components to the blend. The kettle is
typically made from polished carbon steel or stainless steel to promote good
drainage. It is equipped with clean-in-place systems to permit automated
rinsing of the mixing kettle after every batch. Typically the rinsing is done
with a portion of the base component in the products formulation, thus
avoiding the generation of "flush or slop" which would require
additional handling, testing and/or external disposal. Measurement of blending
components might be accomplished through the use of Positive Displacement
Meters, Coriolis Mass Flow Meters, or by mounting the mixing kettle on Load
Cells. Each type of measurement system dictates a different set of physical
requirements for the system, but all can deliver comparable accuracy when
properly engineered. Mixing is achieved using a high-speed agitator in the
kettle, and the batch is transferred to a finished product storage tank for
final homogenization, and filling/packaging operations.
The ABB control system monitors and controls all aspects of the blending
operation, stores and maintains all product formulations and respective
blending recipes, and provides graphic interface at the operator's control
console. The control system can also perform automated pigging control and
higher plant-level functions; such as bulk inventories, laboratory data
handling, interfaces to scheduling and customer service.
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| In-Line Blending (ILB): An ILB is
a pipeline blending system using computer-controlled valves and meters to
introduce blend components into a line or header in a proportional manner.
Typically, there are enough meter/valve combinations that each blend component
can be metered separately. For example, if a product has three components in a
formulation (by volume) of 10%A, 40%B and 50%C, then their respective
meter/valve systems would be set to deliver flow rates of 10%, 40% and 50%
proportionally into the mixing line or header. This type of blender is capable
of delivering homogeneous, on-test product directly to a finished product tank
with no requirement for additional mixing. Flow rates are limited by line size,
the capacity of the blend component pumps feeding the blender, and (because
blending is proportional), by the rate of the slowest component stream. |

ILB with Heat
Exchanger |
The ILB control system monitors and controls all aspects of the
blending operation, stores and maintains all product formulations and
respective blending recipes, and provides graphic interface at the operator's
control console. The control system can also perform automated pigging control
and higher plant-level functions; such as bulk inventories, laboratory data
handling, and interfaces to scheduling and customer service.
In many cases, blends must be made at elevated temperatures to ensure proper
mixing. When this is the case, a heat exchanger can be added to the skid unit
in the blend header between the base oil inlets and the additive inlets. A
typical exchanger would be sized to increase the base oil temperature by about
70F(22C) before introduction of the additive streams.
Our control system features non-proprietary programming using
commercially-available software, so after installation the program can be
easily altered by the client to add new inputs and outputs, change sequences,
change functionality, etc. Our data bases and formulation tables are
spreadsheet-based, so they can be maintained by anyone familiar with Microsoft
Excel spreadsheets. |
Simultaneous Metering Blending
(SMB): An SMB system is similar to in-line blending which uses a
number of meter/valve subsystems to deliver raw materials into a mixing line or
header. This blending method uses a "sandwich" blending approach
introducing a base component into the line first, followed by a mixture of base
component and additives, then finishing with the balance of the base
component(s). All components are transferred directly to the finished product
tank where homogenization takes place. Blending rates are limited only by line
sizes and the capacity of the pumps feeding blending components the blender.
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SMB on Truck |
The main difference between an SMB and an ILB, is the ILB must
blend proportionally and its rate is controlled by that of its slowest
component. An SMB blends simultaneously with all components being added at the
their maximum rates for varying lengths of time. An SMB is therefore more
adaptable to product-slate and/or formulation changes; this is because the
blend component pumps are not sized to fit specific flow ranges.
The SMB control system monitors and controls all aspects of the blending
operation, stores and maintains all product formulations and respective
blending recipes, and provides graphic interface at the operator's control
console. The control system can also perform automated pigging control and
higher plant-level functions, such as bulk inventories, laboratory data
handling, and interfaces to scheduling and customer service. |

Heat Exchanger on
Skid |
In many cases, blends must be made at
elevated temperatures to ensure proper mixing. When this is the case, a heat
exchanger can be added to the skid unit in the blend header between the base
oil inlets and the additive inlets. A typical exchanger would be sized to
increase the base oil temperature by about 70F(22C) before introduction of the
additive streams.
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| Our control system features non-proprietary programming using
commercially-available software, so after installation the program can be
easily altered by the client to add new inputs and outputs, change sequences,
change functionality, etc. Our data bases and formulation tables are
spreadsheet-based, so they can be maintained by anyone familiar with Microsoft
Excel spreadsheets. |
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