Applications for the KDS Micronex Technology
The KDS Reduction System is more than a materials reduction
machine; it is a self-contained environmental solution provider
and profit center. Its versatility, efficiency and durability
make it an ideal investment for a broad range of applications
in a variety of environmentally oriented markets.
Materials that can be processed by the KDS
Micronex™ include:
Alfalfa Hay
Alfalfa
is a very nutritious grass that is widely used as cattle
feed. Often, alfalfa is used as hay and baled
accordingly. It is also possible to pelletize alfalfa
and feed it to cattle. Pelletizing requires that the
alfalfa be ground and dried first. FASC's testing has
proven that the KDS S8 machine can grind alfalfa hay fibers of
25 cm length and 25-30 % water content into a fine powder of 3
mm top size, with a power consumption of 75 kWhr/ton, while
drying it down to 17 % water content. Thus, the KDS can
replace 3 pieces of equipment - drum dryer, hammer mill and
pneumatic conveyor. Further development work is being
done to optimize the application of the KDS to alfalfa
grinding.
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Bagasse
Bagasse
is the name given to the crushed sugarcane after the cane
juice is removed from it. Immense quantities of bagasse
are generated in Louisiana (USA), Brazil, Indonesia and
India. Though it has 40 % water content, it is still
widely used as boiler fuel in the sugar industry.
However, burning bagasse in its wet state significantly lowers
the efficiency of the boilers used to raise steam.
The
KDS exhibits its best drying performance while processing wet
fibrous substances like alfalfa hay, bagasse and deinking
sludge. Limited testing has shown that the KDS uses only
1500 kilojoules of energy to remove 1 kg of water from bagasse.
This is lower than the latent heat of water, because the KDS
uses mechanical forces to dewater bagasse. Limited
testing has shown
that the KDS can dry 0.75 tph feed rate of bagasse from 44 %
water content down to 21 % water content, with a total power
consumption of 120 kW. The product particle size can be
adjusted from coarse fibers to fine powder. Much higher
bagasse feed rates are possible if the grinding motor
horsepower is adequate. It is also expected that the
energy consumption per fed ton will become less, at higher
feed rates. Alfalfa hay, a similar fibrous material,
needs only 75 kWhr/ton grinding energy consumption. At
such low drying energy consumption rates, the power
consumption of the KDS will be much less than the gross
increase in electric power production, when bagasse-fueled
boilers are used for generating electric power. In other
words, there will be a net increase in the thermal efficiency,
which will pay for the extra cost of the drying equipment,
i.e., the KDS Micronex, in a few years time. More
testing of bagasse in the KDS Micronex in Brazil is being
planned.
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Empty Fruit Bunches (EFB or Palm
Waste)
In
Asia, large quantities of palm waste also called Empty Fruit
Bunches or EFB are available from plantations where palm oil
is produced. In its raw state, EFB is both very fibrous
and wet. If it could be dried, it would be an excellent
fuel for power boilers. FASC Malaysia has installed a
KDS machine in the 14 MWe TSH Biomass Power Plant in Kunak, Malaysia,
for the purpose of drying EFB. Called the KDS
MF-777, it
dries and shreds EFB so that it can be burned as a fuel.
At present, only one-sixth of the fuel input needed by the TSH
power plant is supplied by the KDS MF-777. The KDS MF-777 processes
3750 kg/hr of raw EFB having a
moisture content of 52 % and produces 3000 kg/hr of shredded
EFB which has a moisture content of 40 % - this is dry enough
for burning on a grate. The power consumption of the
MF-777 is only 200 kW, under these operating conditions.
This translates to a drying energy consumption of only 960 kJ
per kg of water removal (= 414 BTU/lb) or only 44 % of the
latent heat of water! No other dryer technology can
match the low energy consumption of the KDS
MF-777. It is well-known among power plant engineers
that every percentage point of moisture in the fuel causes
0.5-1 % reduction in the electricity produced. Thus, the
estimated maximum possible increase in the TSH power plant output because of
drying the fuel in the KDS MF-777 is 0.84-1.68 MWe. Thus,
a net overall increase in the total power generated becomes
possible due to the KDS MF-777. Therefore, the
cost of the KDS equipment can be recouped from the
extra revenue from the increased electricity
production.
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Soft Rock Minerals
The
KDS Micronex™ excels in grinding soft rock minerals
into fine particle size. Limestone, gypsum, zeolite (clinoptilolite),
glacial clay, and other soft-rock minerals are all processed
into fine, dry powders. Generally, the KDS Micronex™ grinds soft rock minerals
to particle sizes of less than 75 microns (below 200 mesh)
at production rates of 2-3 tons per hour. The 35-50 kW hr/ton
energy consumption of the KDS Micronex™ is competitive with
smaller horizontal ball mills that do not achieve any supplemental drying.
The KDS machine was selected by clients in California and
Washington State for grinding “solution grade”
limestone, phosphate rock, and/or gypsum. Solution grade fineness
(less than 75 microns) is necessary when soil amendments are
distributed to crops through irrigation systems.
The KDS Micronex™ has been used to process glacial clay
into a fine powder for use in health spas as a body treatment.
The KDS machine is easily able to dry glacial clay from an
initial moisture content of 10 % down to 1 % final moisture
while simultaneously grinding it to below 100 microns (140
mesh).
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Animal Manures
The total volume of animal manure (cow, hog, chicken, and
horse) in the United States is approximately 130 times greater
than that of human waste. Animal manure has a long tradition
of use as an effective fertilizer. However, with modern intensive
agricultural production, manure volumes can exceed the capacity
of nearby croplands to absorb the nutrients in the manure.
Numerous cases have been reported in the media of inappropriately
spread manure contaminating both surface and groundwater and
seriously affecting both human health and the environment.
The KDS System can reduce animal manures to a fine dry powder
which is virtually free of both pathogens and offensive odors.
In this dry state (approx. 10% moisture), the odor is significantly
reduced, and the manure can be stored, efficiently transported,
and sold as a fertilizer. The manure can be blended, at the
time of production, with a variety of other minerals and chemicals
for manufacture of custom fertilizers. Once processed, the
manure can also be pelletized for easy application to farmlands.
The key advantages of the KDS Micronex™ are the lower
operating costs and small space requirements compared with
conventional hammer mill and rotary drum dryer systems. FASC’s
machine footprint is about 100 sq. feet which is
about 1/5 the size of conventional systems. Conventional systems
also require significantly more operating energy to dry manures
compared to the KDS Micronex™.
Dried manure and other biomass can also have a value as a
fuel source. FASC and our joint-venture company Alternative
Green Energy Systems has developed complete turn-key solutions
to cleanly and cost effectively burn manure and generate “green”
power.
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Meat
Packing Waste, Food Waste, Okara
Meat
Packing plants produce a lot of waste, including bones, when
animals are processed into saleable meat. Inedible meat
trimmings from processing are called offal. Recent
concerns about mad cow disease (BSE) have made it impossible
to feed these wastes and offal to cattle. Land-filling
of these wastes is also becoming more difficult.
Recent testing by FASC has proven that after some
pre-processing, meat packing waste and offal can be converted
by the KDS Micronex into fine, dry powders, which are almost
completely bacteria-free. These wastes have to be first
chopped into 3 cm bits and back-mixed with the resulting dry
product before being fed into the KDS. When an initial
quantity of dry product is not available, the process can be
jump-started by feeding a 50:50 mixture of chopped meat waste
plus grain or wood waste. The product can be used as
fish food or even chicken feed, in some cases. When meat
waste and grain are jointly ground and dried in the KDS to
under 12 % moisture content, a nutritious product results.
FASC's earlier experiments with restaurant food waste and
okara also led to similar conclusions.
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Fish
Offal
Fish
processing plants produce a lot of waste, because the head,
tail and bones from each fish are discarded. Such
discarded body parts are called offal. Land-filling
of these wastes is becoming more difficult. However,
these wastes are nutritive enough to make good cattle
feed.
Extensive testing by FASC has recently proven that the KDS
Micronex can convert a mixture of tuna fish offal and grains
into cattle feed that has acceptable nutrient content and no
pathogens. Tests have shown that a 2:1 feed mixture of
grains : thawed fish offal will result in 0.5 tons/hour of
fine powder having under 20 % moisture content, with a power
consumption of 150 kW and no sticking inside the KDS
machine. A 1:1 mix of grains : tuna offal too can be
successfully processed if the grains and tuna offal are
carefully pre-blended in a mixer. The resulting
production rate was found to be 0.4 tons/hour with a similar
moisture content and power consumption. The product was
a fine, light brown odor-free powder in which no fish
flesh could be discerned. The powder was fed to cattle
over a 2 week period, with good results. The wheat grain
sells for $130 per ton, so the production economics are quite
favorable.
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Deinking Sludge
Sludges
from paper making and paper recycling (de-inking sludge) are
generated in large quantities throughout North America. Currently
common sludge management practices of land-filling and land-application
are under increased environmental scrutiny and are becoming
increasingly costly.
The KDS Micronex™ can dewater deinking sludge and enable the
separation of paper fiber from other paper components (i.e.
kaolin clay). The paper fiber can be recovered for fuel or
recycled as fiber. Kaolin clay can be recycled in the papermaking
process or other industrial applications. The removal of clay
also significantly increases the fuel value of and reduces
the ash created during combustion. FASC’s joint venture
company – Alternative
Green Energy Systems has designed turn-key solutions
using the KDS Micronex™ to recycle sludges from the
pulp and paper industry.
Extensive independent testing of the KDS done in the U.K
show that 900 kg/hr feed rate of deinking sludge can be dried
down from 38 % moisture to 16 % with a total power consumption
of only 90 kW and a water removal rate of 236 kg/hr.
Thus,the specific power consumption was 100 kWhr for a metric ton
of input material and 136 kWhr per ton of output product.
The water removal energy was 381 kWhr/ton or 1373 kilojoules
per kg of water removal., or 1.373 GJ/ton. It
must be noted that the theoretical minimum energy for water
removal is called the latent heat of water and equals about
2258 kilojoules per kg of water. In practice,
conventional thermal dryers use up to 3800 kilojoules of
energy to remove 1 kg of water, i.e., 3.8 GJ/ton.
Thus, the KDS uses only 36 % of the energy that a
conventional dryer uses in the form of heat.
Assuming
that electric power costs $0.06/KWhr and natural gas (the
cheapest of all conventional dryer fuels) costs $8 per
gigajoule (actual recent
natural gas futures price in New York), the drying energy
cost per ton of water removed is 0.06 x 381 = 22.86 dollars per ton of water removed in the KDS. In a conventional
dryer, the cost would be 3.8 x 8 = 30.4 per ton
of water removal.
Thus, the KDS has a 25 % cost
advantage over conventional dryers, assuming that the
relative prices of electricity and natural gas stay the
same.
It must be emphasized that clay and fiber components of
deinking sludge CANNOT be separated from the deinking sludge
dried in a drum dryer. In contrast, the KDS produces
a fluffy, fibrous product which enables the clay to be
separated from the residual fiber which then can be burned in
boilers as fuel. The clay can be calcined and reused in the
paper-making process.
Similarly extensive testing done in Ontario, Canada with a
local deinking sludge showed that deinking sludge can
be dried at similar feed rates and power consumption from an
initial water content of 50 % to a final water content of 15
%, i.e., water removal rate of 370 kg/hr with a total power
consumption of 100 kW.
This represents even better economics than in the U.K
testing, i.e., 33 % cost advantage over a natural gas-fired
dryer.
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Coal
About
half of the electricity generated in the United States comes
from coal-fired power plants. In all large power plants, coal
is dried and pulverized in a ball mill to under 75 microns
(200 mesh) before being burned. The drier the coal, the higher
the value for burning. Coal's moisture content can vary widely
from 5 to 50 %. Recent testing by FASC indicates that bituminous
coal can be dried from 15 % to 4 % final moisture content
and ground to a median diameter of 63 microns (230 mesh) at
a production rate of 3 or 4 tons per hour. The grinding energy
consumption of 30-40 kW hr/ton is competitive with that of
small ball mills.
Unlike ball mills, the KDS machine reuses that grinding energy
to dry the coal, hence is actually more efficient. With the
KDS Micronex, it is possible to increase the value of lower
grade coals which have limited use at present.
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Bio solids (Sewage Sludge)
Sewage
sludge, also called digested sludge or “bio solids” are created at wastewater
treatment plants as water is processed and purified. Currently
many municipalities are facing challenges to environmentally
and economically dispose of wastewater treatment plant bio
solids.
The KDS Micronex™ can dewater bio solids to reduce their
volume and the associated transportation and disposal costs.
The KDS Micronex™ is certified by the US Environmental
Protection agency for its ability to destroy pathogens including
salmonella, e-coli, and fecal coliforms. The dry powders produced
by the KDS Micronex™ are suitable for land application
or for use as a fuel source where they can replace fossil
fuels.
Extensive testing in British Columbia, Canada has shown
that digested sludge containing 80 % water can be processed at
the rate of 300 kg/hr and that the resulting product had only
10-13 % water content. The fecal coliform count was
consistently reduced from over 4 million MPN/gram (Most
Probable Number of fecal coliforms per gram) in the raw
digested sludge to well under 1000 MPN/gram in the dried
product. This means that the product from the KDS
Micronex met Class A standards for biosolids, i.e., the KDS
can convert Class B biosolids to Class A biosolids, which are
much more valuable as fertilizer. The power consumption
was 500 kWhr per metric ton of raw digested sludge. A
detailed economic analysis shows that the processing cost will
be $80 per wet ton of digested sludge, including amortization,
labor and power costs. In other words, the production
cost of one bone-dry ton of product will be $400.
According to a leading academic researcher, competing
technologies that convert Class B to Class A biosolids have
processing costs ranging from $400 to $800 per bone-dry
ton. Thus, the economics of the KDS for this application
are extremely competitive. While this sludge-derived
fertilizer is still rather expensive to produce, it is
environmental regulation which requires that wastewater sludge
be rendered pathogen-free. Hence, wastewater sludge
beneficiation is one of the best applications for the KDS
Micronex.
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Gypsum Wallboard
Gypsum
wallboard (gyproc or sheet roc) comprises about 10% of all
the waste materials left over following construction/renovations
in North America.
When gypsum degrades in the low oxygen environment of landfills,
hydrogen sulphide is generated. This gas contributes to both
air and water pollution. As a result, government agencies
are looking to encourage recycling to keep drywall out of
landfills. Currently there are only a few specialized facilities
for processing waste drywall in North America.
The KDS System reduces drywall to a powder that can be utilized
as a soil amendment or recycled into the production on new
building materials. The powder produced from the processing
of drywall is compact, consistent in particle size, dry (less
than 10% moisture content) easily packaged or bulk loaded
for distribution.
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Glass
Though
already recycled in large quantities, the value of recycled
glass is generally low and the costs of transportation can
make recycling uneconomical.
Glass fragments introduced to the KDS system in pieces 2”
in diameter, or less, are ground at the rate of 1 - 1.5 tons
per hour into a fine powder. The powder is smooth and fine
to the touch, without sharp edges. The maximum particle size
is about 150 microns and about half of the powder is below
45 microns.
Even finer particle sizes have been achieved with the KDS
system at lower feed rates. In one such test, 18 % of the
glass powder, i.e., 200 lb/hr of output had a particle size
of less than 1 micron. The grinding energy required was only
200 kW hr/ton. No other grinder can produce sub-micron glass
powder in such large quantities while consuming so little
energy. Such fine glass powder can command high prices as
an industrial feedstock.
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Wood Chips, Sawdust and Bark
In
North America, wood waste, unsuitable for timber or pulp can
be a disposal problem for the forestry industry. Wood waste
can be efficiently burnt and is a renewable energy source;
but wet wood is often only marginally economic because up
to 40% of the heat value in the wood is used to dry the moisture
in the wood chips.
The KDS Micronex™ technology is an alternative to traditional
methods of drying wood. The KDS Micronex™ combines both
the pulverizing and drying operations in one compact machine,
simplifying the process. Furthermore, the system is tolerant
of contaminants such as dirt and stones that can cause sparking
and fires in hammer mills.
While grinding spruce/pine/fir (SPF) hog fuel of 25 mm size
and 14 % water content, the KDS
consumes 150 kW for every ton per hour of product having a top
size of 2 mm and median size of 600 microns. With 50 %
moist SPF or hemlock wood chips, the energy consumption is 300
kWhr/ton. 135 kg/hr of water are removed when the
grinding power consumption is 150 kW.
SAWDUST: FASC has dried and ground wet sawdust from initial
moisture of 48 % down to 15 % while also making a fine powder out
of it. 185 kg/hr of such fine powder having a median
particle size of 250 microns was produced with a grinding
power consumption of 140 kW. This fine, dry powder was then utilized
to make wood-plastic composite. The KDS was leased as the
equipment of choice because no separate dryer or heat source
was necessary. Hammer-mills are unsuitable for such fine
grinding. Attrition mills can be used but they require
the feedstock to be first pre-processed in a hammer mill and
their capacity is limited. A scientific paper by
Holtzapple et al. reports that attrition mills have an energy
requirement of 261 kWhr/ton (0.94 MJ/kg) to grind down to 850
microns and 656 kWhr/ton (2.36 MJ/kg) to grind down to 106
microns top size. This does not include the energy
required for drying the wood. An economic analysis shows
that in this particular case, the KDS and conventional
technology are roughly comparable in terms of their energy
cost. The KDS does have the advantage of requiring no
heat input and combines the functions of both a conventional
dryer and grinder.
BARK: A test in which SPF bark was ground and dried in the
KDS showed that 636 kg/hr of bark having 50 % water content
could be ground and dried to produce 361 kg/hr of product
having 12 % final moisture content and median particle
diameter of 250 microns. The water removal rate was 277
kg/hr (twice that achievable with wood) and the total power
consumption was 180 kW. Such fine grinding down to 250
microns median diameter is required if the bark powder is to
be burned in a dust burner.
At $0.06/kWhr electricity cost, the combined grinding and
drying energy cost in the KDS was calculated to be $16.98 per
metric ton. The conventional technology to dry and grind
wet wood-bark is a drum dryer, hammer mill and attrition mill
combination. With $8/GJ dryer fuel cost and an energy
consumption of 3.8 GJ per ton of water, the drying cost in a
drum dryer would have been $8.42 per hour or $13.24 per metric
ton of feed material. The grinding cost would have been
$6.5 per hour or $10.21 per feed ton, assuming 300 kWhr/ton
grinding energy requirement in the hammer mill and attrition
mill [Ref: Holtzapple et al.]. Thus, with conventional
technology, the total drying and grinding cost would have been
$23.45 per feed ton. Thus, the KDS, in this case, has
a 27 % cost advantage over conventional technology.
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Precious Metals
The
KDS System enables a completely unique method of extracting
gold from quartzite rock. While quartzite is being ground
in the KDS Micronex™, the heavy gold-rich particles
tend to stay in the grinding chamber called the clam and the
rest of the ore is pneumatically conveyed out of the KDS machine.
Gold recoveries of up to 90 % and quartzite grinding
rates of 2 tons per hour have been achieved. This method of
gold extraction is potentially revolutionary for gold mining.
Currently research is ongoing to commercialize this application.
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