Chemicals
based Technologies-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
