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 further information please contact

Mr. S.S. Verma
Department of Physics,
S.L.I.E.T., Longowal
Distt.-Sangrur (Punjab)- 148106
E-mail : ssverma123@rediffmail.com