News
Australian
stock feed company implements online moisture analysis for
quality control
23rd February 2010
A large Australian stockfeed manufacturer has adopted MoistScan®
technology to maximise quality control at its feed pelletizing
plant in Western Australia.
The company produces 60,000 tonnes of specially formulated feed
pellets each year for feedlots and for stock feed for the live
cattle and sheep export business. The provision of quality feed
plays an integral role in ensuring that stock are healthy before
they board a vessel, and when they walk off.
Critical to quality control is moisture. The company makes a
feed pellet which consists of lupins, wheat, barley, triticale
and straw. The grains are milled in a hammer mill before being
mixed with finely chopped straw in a horizontal spiral mixer.
The raw meal is then fed to a mash tank which feeds a
conditioner. In the conditioner the mixed meal is directly
pre-heated with dry steam. The steam preheats the meal to the
preferred temperature and moisture content for pelleting
according to the formulation of the mixture. During pelleting
the temperature of the meal rises. Moisture during conditioning
and in the final pellet is central to quality as it ultimately
affects the amount and nature of starch and protein in the raw
materials and the binding qualities of the pellet. This all
affects the available energy and digestibility of the feed.
By “getting the moisture right” the nutritional value of the
pellet is maximized as to is the operational efficiency of the
pelleting process.
The company “scoured the marketplace” to find a solution however
nothing suitable was found. After discussing the project with
Callidan sales division our engineering division went about
designing an online moisture analyser capable of measuring the
moisture in the meal as it was being transported to the
conditioner by an auger at the bottom of the mash tank. This
required the fabrication of special antenna and housings that
fitted the curvature of the bottom of the mash tank. It also
required a program logic that would “blank out” any interference
from the flight of the auger on the microwave reading.
Using Callidan’s MoistScan® microwave technology, the customized
antenna creates a microwave zone of analysis that measures all
the material being conveyed by the auger to the conditioner. The
moisture percentage is output as a 4-20mA current signal which
is fed into the plants computer. Here is it used in a feed
forward control loop to regulate the addition of dry steam to
the conditioner such that the moisture in the pellet after it is
extruded is 16%.
This is just one example of where Callidan instruments
engineering division has custom designed an analyser for a
client where on off-the-shelf solution could not be found. Many
applications that we encounter have application-specific issues
which need to be taken into consideration. First and foremost,
we ensure that we understand what it is that our client wants to
achieve through online moisture analysis. We seek to understand
your process and the variables which may affect the performance
of the instrument. With the customers end in mind, we then are
in a position to develop the ideal solution.
ENDS..
Measuring moisture in wood waste in a screwfeeder
22nd February 2010
Online moisture analysis specialist Callidan Instruments
recently custom built a moisture analyser for a large US company
that generates industrial steam and electrical power from waste
biomass.
Late in 2009, the company contacted Callidan through their East
Coast US distributor Kanawha Scales and Systems when they “came
up blank” after scouring the market place for an online moisture
anlayser to suit their application.
The US Company recycles and reuses the waste generated by
agriculture, construction, felled trees and a variety of other
sources, reducing both solid waste and atmospheric pollutants.
Biomass waste is currently unnecessarily filling landfills or
burned or left to decompose at the production site, increasing
air pollution.
Measuring and controlling moisture in the biomass waste is
integrally important to the energy generation process. The
material is delivered, pulverized, stored and dried before being
blown into a cyclonic combustor where it is combusted to produce
steam for electricity generation.
The moisture of the pulverized wood waste has a direct affect on
the efficiency of the dryer and the combustion process. The wood
waste is fed into the dryers by screwfeeders. To keep a tight
control on the moisture the engineering team wanted to measure
the moisture in real time and wanted to measure it as close to
the inlet of the dryers as possible. In the screwfeeder was the
obvious choice.
Callidan Instrument engineering division went about designing an
online moisture analyser capable of measuring the moisture in
all the material as it was being conveyed in the screwfeeder.
This required the fabrication of specials antenna and housings
that fitted to tube of the screw. It also required specialist
programming to “blank out” any interference from the flight of
the screw on the microwave reading.
Using Callidan’s MoistScan® microwave technology, the customized
antenna creates a microwave zone of analysis that measures all
the material in the screwfeeder. The moisture percentage is
output as a 4-20mA current signal which is fed into the plant
DCS. Here is it used in a feed forward control loop to regulate
the operation of the dryer. The ultimate objective is to ensure
that the pulverized biomass is at the ideal moisture before it
is fed to the cyclonic combustor.
ENDS
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