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Amiraculous Technology for Converting
Waste to Wealth
Waste's Problem
"Waste" is an inevitable by-product of
natural as well as man made activities. When Nature has full
control in managing its waste into useful resources Man too
has devised various methods to utilize the limited waste in
useful ways. But generation of waste in large quantities due
to man made activities that is turning into garbage is creating
serious environmental problems. India is moving very fast
towards the society with a philosophy of "use and throw",
show business with packaging syndrome and no reuse of items
etc. and this all is generating a heap of garbage in and out
of our houses to tackle. Still this life attitude is limited
to a very small fraction of our population but to what extent
it will grow when a population of 100 billion will contribute
towards this growing menace of garbage, is just an imagination.
There is a great need to change our way of life as well as
to devise technologies for recycling of used materials. Moreover,
it is required to develop technologies, which are cost effective
and environmental friendly to change all types of garbage
into some useful and products. In this direction a latest
miraculous technology making use of Thermal Depolymerization
Process (TDP) is reported to change any garbage into use full
finished products. A brief introduction to this technology
is presented here.
Natural waste management
Many scientists have tried to convert
organic solids to liquid fuel using waste products before,
but their efforts have been notoriously inefficient. The problem
with most of these methods was that they tried to do the transformation
in one step-superheat the material to drive off the water
and simultaneously break down the molecules. That leads to
profligate energy use and makes it possible for hazardous
substances to pollute the finished product. Very wet waste-and
much of the world's waste is wet-is particularly difficult
to process efficiently because driving off the water requires
so much energy. Usually, the energy content in the resulting
oil or gas barely exceeds the amount needed to make the stuff.
Prof. Baskis, a microbiologist and inventor from Illinois
(USA), confronted about how to improve the basic ideas behind
waste reforming process and worked out the Thermal depolymerization
Process (TDP). TDP makes use of an age-old trick that Earth
mastered long ago for making oil and gas from hydrocarbon-based
waste. Most crude oil comes from one-celled plants and animals
that die, settle to ocean floors, decompose, and are mashed
by sliding tectonic plates, a process geologists call subduction.
Under pressure and heat, the dead creatures' long chains of
hydrogen oxygen, and carbon -bearing molecules known as polymers,
decompose into short-chain petroleum hydrocarbons. However,
Earth takes its own sweet time doing this-generally thousands
or millions of years-because subterranean heat and pressure
changes are chaotic. Thermal depolymerization machines turbo-charge
the same process by precisely raising heat and pressure to
levels that break the feedstock's long molecular bonds in
a reduced time span.
Thermal depolymerization Process
Thermal depolymerization process (TDP)
is designed to handle almost any waste product imaginable,
including turkey offal, tires, plastic bottles, harbor-dredged
muck, old computers, municipal garbage, cornstalks, paper-pulp
effluent, infectious medical waste, oil-refinery residues,
even biological weapons such a anthrax spores except nuclear
wastes. In the process, waste goes in one end and comes out
the other as three products, all valuable and environmentally
benign: high-quality oil, clean-burning gas, and purified
minerals that can be used as fuels, fertilizers, or specialty
chemicals for manufacturing. Therefore, a thermal depolymerization
machine (Figure 1), an intimate human creation could become
a prime feedstock. The company that built this pilot plant
has just completed its first industrial-size installation.
The potential associated with the process is unbelievable.
Only cleaning up of waste will produce oil. This is a solution
to three of the biggest problems facing mankind I) growing
waste ii) support to dwindling supplies of oil and iii) slow
down global warming. Unlike other solid-to-liquid-fuel processes
this process will also accept almost any carbon-based feedstock
therefore, this is also called as switching to a carbohydrate
economy. It is reported that technological savvy could turn
600 million tons of turkey guts and other waste into 4 billion
barrels of light oil each year. Thus garbage will no longer
go to waste and each day 200 tons of turkey offal will be
carted to thermal depolymerization plant to transform it into
various useful products, including 600 barrels of light oil.
The oil thus produced is very light oil and the same as a
mix of half fuel oil and half gasoline.
How does it work?
Thermal depolymerization process is not
alchemy but pure chemistry that turns (A) turkey offal-guts,
skin, bones, fat, blood, and feathers-into a variety of useful
products. After the first-stage heat-and-pressure reaction,
fats, proteins, and carbohydrates break down into (B) carboxylic
oil, which is composed of fatty acids, carbohydrates, and
amino acids. The second-stage reaction strips off the fatty
acids' carboxyl group (a carbon atom, two oxygen atoms, and
a hydrogen atom) and breaks the remaining hydrocarbon chains
into smaller fragments, yielding (C) a light oil. This oil
can be used as is, or further distilled (using a larger version
of the bench-top distiller in the background) into lighter
fuels such as (D) naphtha, (E) gasoline, and (F) kerosene.
The process also yields (G) fertilizer-grade minerals derived
mostly from bones and (H) industrially useful carbon black.
The apparatus for TDP consists of a tangle of pressure vessels,
pipes, valves, and heat exchangers terminating in storage
tanks and resembles the oil refineries. The chief difference
in TDP to other processes is that TDP makes water a friend
rather than an enemy. The other processes all tried to drive
out water where as TDP drives it in, inside the tank, with
heat and pressure and then super-hydrate the material. Thus
temperatures and pressures need only be modest, because water
helps to convey heat into the feedstock. The temperatures
are of the order of 2600C and pressures of about 600 pounds
for most organic material not at all extreme or energy intensive
and the cooking times are pretty short, usually about 15 minutes.
Once the organic soup is heated and partially depolymerized
in the reactor vessel, phase two begins in which slurry is
quickly dropped to a lower pressure. The rapid depressurization
releases about 90 percent of the slurry's free water. Dehydration
via depressurization is far cheaper in terms of energy
consumed than is heating and boiling off the water, particularly
because no heat is wasted. The flashed-off water is sent back
to the beginning of the process to heat the incoming stream.
At this stage, the minerals are settled out and are shunted
to storage tanks. Rich in calcium and magnesium, the dried
brown powder is a perfect balanced fertilizer. The remaining
concentrated organic soup gushes into a second-stage reactor
similar to the coke ovens used ot refine oil into gasoline.
The reactor heats the soup to about 5000C to further break
apart long molecular chains. Next, in vertical distillation
columns, hot vapor flows up, condenses, and flows out from
different levels: gases from the top of the column, light
oils from the upper middle, heavier oils from the middle,
water from the lower middle, and powdered carbon-used to manufacture
tires, filters, and printer toners-from the bottom. As gas
is expensive to transport, so efforts are made to use the
produced gas on-site in the plant to heat the process.
Conclusion
When waste has become the growing problem,
the TDP has the potential to change the whole industrial equation
related to waste management and waste management will go from
a cost to a profit. The equipment, the procedures, the safety
factors, the maintenance related to TDP-it's all proven technology.
Depending on the feedstock and the cooking and coking times,
the process can be tweaked to make other specialty chemicals
that may be even more profitable than oil. Turkey offal, for
example, can be used to produce fatty acids for soap, tires,
paints, and lubricants. Polyvinyl chloride, or PVC-the stuff
of house siding, wallpapers, and plastic pipes-yields hydrochloric
acid, a relatively benign and industrially valuable chemical
used to make cleaners and solvents. The hydrogen in water
combines with the chlorine in PVC to make it safe where as
burning PVC in a municipal-waste incinerator generates dioxin-very
toxic. Hence, it is the perfect process for destroying pathogens.
Thermal depolymerization has proved to be 85 percent energy
efficient for complex feedstock and the efficiency is even
better for relatively dry raw materials, such as plastics.
Scientists and technologists anticipate that a large chunk
of the world's agricultural, industrial, and municipal waste
may someday go into thermal depolymerization machines scattered
all over the globe to produce useful end products in an environmental
friendly way. If the process works well as its creators claim,
not only would most toxic waste problems become history, so
would be imported oil. Thermal depolymerization process will
not only clean up wastes but also generate new sources of
energy.
For farther detail contact :
Mr. S.S. Verma
Department of Physics,
S.L.I.E.T., Longowal
Distt.-Sangrur (Punjab)- 148106
E-mail : ssverma123@rediffmail.com
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