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8/6/2019 Maxim is Ing Biogas Production Efficiency
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WORLDPUMPSFebruary 2011Feature323232
www.worldpumps.com 0262 1762/11 2011 Elsevier Ltd. All rights reserved
Biofuel processing
Maximising biogasproduction efficiency
The biofuels sector, including biogas, is a fast growing industry
because it means less reliance on fossil fuels, and it is sustainable.
However, biomass is a difficult media, so has to be broken down
to allow pumping to take place efficiently and to maximize biogas
production. Harald Vogelsang explains.
Biogases are gases produced by the
biological breakdown of organic
matter in the absence of oxygen.
Such gases mainly methane and carbon
dioxide (CO2) are produced by anaerobic
digestion or fermentation of biodegradablematerials, which include municipal waste,
biomass, manure/sewage, green waste, and
energy crops (Figure 1).
As methane can be burned, it makes an
ideal low-cost and relatively green sustain-
able and renewable fuel to power any
form of heat engine to generate either
mechanical or electrical power. It can also
be compressed to power vehicles. Biofuels,
such as biogases, therefore help reduce
reliance on often dirty and increasingly
expensive fossil fuels.
Many biogas plants originally started in
Germany, because German farmers typically
had slurries they needed to be rid of this
provided the biomass from which biogases
could be obtained. In addition, there were
biogas plants for producing power out of
various wastes, including biological waste.
Ever since the biogas boom started about
a decade ago, the demand for biogas tech-
nology has become very strong, and there
is increasing interest around the world. In
Germany, for example, there is currently a
great deal of business to be had in biogas
production, pumping and storage, which
involves, among other things, biomatter
crushing techniques and signifcant use of
pumps. Apart from the intrinsic merits of
biogas, one significant reason for this is
that biogas demand has been increasing
because of legislation. In Germany, compa-
nies are paid for any power they supply
to the grid. The legislation was changed
recently, so that electrical power produced
from biogas now obtains a high purchase
price for electricity generating companies.
It is this aspect that has helped the biogas
boom in Germany, but other countries
either have similar legislation or are likely to
have it soon.
Figure 1. Biodegradable materials include municipal waste, biomass, manure/sewage, green waste, and energy crops.
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Pump manufacturers, being often involved in
supplying large products for very big projects,
have a much more immediate feel for how
economies are doing around the world,
because they are much more international in
terms of contract placements, which are often
municipal or governmental. This feeds back
a realistic barometer of the general global
economic situation, because when money
starts to be spent on biogas or wastewaterprojects, pump manufacturers know that
money is being released through various
government departments and budgets.
Biomatter preparation
Biomass is a difficult media, so has to be
broken down to allow pumping to take
place efficiently and to maximize the biogas
yield. The biomatter has to be crushed or
cut, so that fibres and biological matter
are chopped up, creating a greater surface
area that makes it easier for the bacteria to
digest the material. In addition, any heavy
objects must be removed before processing
can proceed further.
This is achieved using high performance wet
cutters and macerators having an integrated
heavy object separator. Such machines areoften similar to those used in the waste-
water treatment industry (sludge and very
dirty wastewater present similar problems),
but biogas is a much newer industry with
heavier end user involvement. Biogas
companies tend to take greater ownership
and are more involved with the plant design
from the very beginning.
Hugo Vogelsang Maschinenbau GmbH, for
example, is a leading designer and manufac-
turer of agricultural, municipal and industrial
products that are used to prepare biodegrad-
able materials for biogas production plant. The
company is also a pump manufacturer but it
focuses on the biogas and wastewater treat-
ment sectors, and on agriculture and the oil
industry. Even over the past year, the company
grew 10% despite the recession, and it has
seen years with 30 to 40% growth. As a result,
it expects good future turnover and profit.
Importantly, a significant part of this is built
upon the biogas sector.
Products for these sectors include wet cutters,
macerators and rotary lobe pumps, and
combinations of the two. The high demandfor products such as these that disintegrate
biomass and biological materials is because
they are exactly what biogas industry needs.
Biomass preparation
The crushing and macerating machines, like
Vogelsangs RotaCut (Figure 2), solve typical
problems involving coarse and fibrous foreign
matter and foreign objects in liquid media.
The liquid media flows continuously through
the unit. Foreign objects such as stones, metal
parts, etc are separated by gravity and caneasily be removed later through a cleaning out
port. All material that floats, such as fibrous
materials, bones, wood, etc, are carried by the
flowing medium to the cutting screen where
the solids are cut up using rotating, self-sharp-
ening knives. In this way, foreign objects are
separated, while coarse and fibrous materials
are chopped up, making the liquid medium
homogeneous. The method also keeps all
foreign objects away from pipe systems,
preventing pump clogging and helping to
assure trouble-free system operation. Blockage
protection is available through the auto-reverse function.
Four different heavy object separators are
available for different applications and media.
These are: cyclone with heavy object separator;
intake and discharge arranged in-line; the MXL
that is ideal for vehicle mounting; and the
compact XL model. Different drive systems
and hardened steel cutting screen sizes also
help customers meet varying applications.
Another way of disintegrating biological
materials is by using high voltages. Theprocess is extremely good at disintegrating
these, providing a greater surface area that
makes it easier for the bacteria to consume
the biomatter. The result is extra gas yield out
of the digested material up to 18% more.
Vogelsangs BioCrack (Figure 3) works this way,
and its other great advantage is that very little
energy is used each system runs using just
35 W of power. This relatively new technology
also works well with macerating machines,
such as RotaCut. Typically, a rotary lobe pump
is used to flush through a RotaCut into the
BioCrack, recycling material to the digesterin exactly the right form for efficient biogas
production.
Such a system reduces the power required for
mixing a very significant benefit, because
conventionally, mixing is energy intensive.
Several technologies from various manufac-
turers are available that provide good biomate-
rial disintegration, but the energy demand is
high, and an increasing number of end-users
are requesting greater energy savings. The
combination of RotaCut and BioCrack is ideal
for obtaining good results at very low cost.
Figure 2. Crushing and macerating machines, such asVogelsangs RotaCut, solve typical problems involving
coarse and fibrous foreign matter and foreign objects in
liquid media.
Figure 3. Vogelsangs BioCrack uses high voltages to
disintegrate biological materials. One great advantage is
that very little energy is used each system runs using just
35 W of power.
Figure 4. Vogelsang rotary lobe pumps such as this VX230
model are used in conjunction with biomass crushers,
cutters and macerators.
Figure 5. BioCut is a combination of rotary lobe pump and
the RotaCut wet shredder.
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Elastomer-coated pumps
Vogelsang rotary lobe pumps (Figure 4) are used in conjunction with
biomass crushers, cutters and macerators, sometimes in the same unit,
such as the BioCut (Figure 5), which is a combination of rotary lobe
pump and RotaCut wet shredder. These pumps can easily handle even
abrasive media, acids or liquids with high solids content.
To meet virtually any application, the pumps are available in various
materials, including grey cast iron with tungsten carbide (TC) coating,
aluminium or stainless steel, with combinations of hardened and/
or coated housing and wear components. There are also mechanical
sealing options, including as a cartridge, with duronite or SiC, and there
are various lobe materials and geometries that can be provided to suit
specific applications.
The advantages of this type of pump for the biogas, wastewater,
sewage treatment, recycling, drinking water supply and other sectors
are as follows:
Changeable pumping direction Self-priming Insensitive to running dry, foreign objects and particles Compact design allowing reduced space requirements Pulsation-free lobes Flow rate proportional to pump speed Very good accessibility for maintenance and repair.
Improving maintenance
The bio industry is very demanding because of the highly diffi cult
media that systems have to contend with. Examples include sludge
and maize, which both contain much dirt, such as sand, stones andforeign bodies. All of this has to be mixed together and pumped to
all of the bio-units. This is a very abrasive and demanding material,
and can quickly wear pumps and other equipment, so customers
are requesting that lifetimes be improved. Research and develop-
ment is ongoing into this crucial aspect.
A related aspect is ease of maintenance, which is one of the key
features for customers. Everything must be accessed very easily; it
must be possible to remove and replace worn parts quickly.
Figure 6. A Vogelsang rotary lobe pump showing the coated lobes.
ContactHolger Eggert
Director of Marketing
Hugo Volgelsang Maschinenbau GmbH
Holthoge 10 - 14, D-49632
Essen Oldb, Germany
Tel: +49 5434 83 231
Email:[email protected]
Web: www.vogelsang.info
mailto:[email protected]:[email protected]://www.vogelsang.info/http://www.vogelsang.info/mailto:[email protected]