The Tribune, Chandigarh, India

Oil and gas from waste products
S.S. Verma

"WASTE" is an inevitable byproduct 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 utilise 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 is generating a heap of garbage in and out of our houses to tackle. Still, this attitude is limited to a very small fraction of our population but to what extent it will grow when a population of 10 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 end products. In this direction a latest miraculous technology making use of Thermal Depolymerisation Process (TDP) is reported to change any garbage into useful finished products.

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 TDP that 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 shortchain 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 depolymerisation 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.

The TDP is designed to handle almost any waste product imaginable, including turkey offal, tyres, plastic bottles, harboar-dredged muck, old computers, municipal garbage, cornstalks, paper-pulp effluent, infectious medical waste, oil-refinery residues, even biological weapons such as 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, fertilisers,or specialty chemicals for manufacturing.

Therefore, a thermal depolymerisation 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 a thermal depolymerisation 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.

Thermal depolymerisation 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)fertiliser-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 the TDP makes the water a friend rather than an enemy. The other processes all tried to drive out water whereas the TDP drives it in, inside the tank, with heat and pressure and then super-hydrates 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 260`B0C 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 depolymerised in the reactor vessel, phase two begins in which slurry is quickly dropped to a lower pressure. The rapid depressurisation releases about 90 per cent of the slurry’s free water. Dehydration via depressurisation 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 fertiliser. The remaining concentrated organic soup gushes into a second-stage reactor similar to the coke ovens used to refine oil into gasoline.

The reactor heats the soup to about 500`B0C to further break apart long molecular chains. Next, in vertical distillation columns, hot vapour 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 tyres, 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.

When waste has become the growing problem, the TDP has the potential to change the whole industrial equation related to waste management. 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 cooking 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, tyres, 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 whereas burning PVC in a municipal-waste incinerator generates dioxin — very toxic. Hence, it is the perfect process for destroying pathogens.

Thermal deploymerisation has proved to be 85 per cent 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 depolymersation 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 depolymerisation process will not only clean up wastes but also generate new sources of energy.

The writer is from the Department of Physics, SLIET, Longowal.

NEW PRODUCTS & DISCOVERIES
Computer control by eye

Computers of the future could be controlled by eye movements, rather than a mouse or keyboard.

Scientists at Imperial College, London, are working on eye-tracking technology that analyses the way we look at things.

The team is trying to gain an insight into visual knowledge - the way we see objects and translate that information into actions.

"Eye-trackers will one day be so reliable and so simple that they will become yet another input device on your computer, like a much more sophisticated mouse," said Prof Guang-Zhong Yang of the Department of Computing at Imperial College.

The scientists at Imperial College have been using an infra-red eye-tracking headset to understand how the eye moves when given a task.

For the research, people have been shown an image and given a limited amount of time to find a specific target, such as a waving hand in a crowd.

Searching for something like a hand in a crowd requires as much mental effort as, for example, solving a crossword puzzle. The scientists are trying to understand how this visual knowledge works.

"You can see things but you may not be able to recognise things," Professor Yang told the BBC programme Go Digital.

"It is the only when the eye registers with the cognitive part of the brain that things start to happen.

"We are trying to unravel how biological visual systems work and reverse-engineer better computer vision systems," he said.

The team is looking at applying its research for use in areas such as keyhole surgery or robotic surgery.

"If you want to operate on a moving object using keyhole surgery, such as the beating heart to do a coronary bypass, you want to have a stable view," he explained. BBC

Battery that runs on alcohol

From scientists at Saint Louis University comes a gadget fit for a James Bond movie. Imagine 007 sauntering up to the bar, ordering his trademark martini (shaken, not stirred) and, before taking a sip, topping off his cell phone with a few drops of alcohol to recharge the battery.

Researchers have developed a new type of biofuel cell — a battery that runs off alcohol and enzymes — that could replace the rechargeable batteries in everything from laptops to Palm Pilots. Instead of plugging into a fixed power outlet and waiting, these new batteries can be charged instantly with a few milliliters of alcohol. The new findings were presented at the 225th national meeting of the American Chemical Society, the world’s largest scientific society, in New Orleans.

Biofuel cells have been studied for nearly half a century, but the technology has not advanced to the point of practical use. Instead of using expensive metals to catalyse the power-producing reaction, these cells use enzymes — molecules found in all living things that speed up the body’s chemical processes. American Chemical Society

UNDERSTANDING THE UNIVERSE
WITH PROF YASH PAL

Does the intelligence of a person depend on the size of his skull? I am a student and do not feel comfortable in front of people who have bigger skulls than me.

I would straight away tell you to stop worrying. I know a lot of very intelligent persons with small heads and a quite a few who have big skulls and are not so bright. All of us use only a small fraction of our processing power. In absolute terms it is not only the sheer size that matters but also the structure and folds. Even more, brain needs nourishment and exercise, both physical and mental. Many of its powers develop through use and others die out if left unused. Just concentrate on that and stop feeling inferior when in front of swollen heads.

Will life on Mars be possible in next 10 years?

Human beings might visit Mars in 10 years or so. But they will have to live in the capsules they go in or build up there. Building cities and colonies is a distant dream. Talking of dreams there are people who are making plans for converting Mars into an earthlike planet. It is not so different in size and does show evidences that at one time it had lot of water flowing on its surface.

If human kind really wants to make Mars into an earth like planet, with plants, atmosphere rain and clouds, it will have to use biological means and it might take a few centuries if not a few millennia. I am not sure we have enough patience or cooperation for projects like this. We only think in terms of military bases and ways of dominating and conquering others. I personally think there is a lot to be done here on earth if only we will.

We have to remember that it is impossible to think of a habitat that contains only one species. Even we are not just one species alone. We would not be possible if we did not have within us a large number of other species inhabiting the world within us in a symbiotic relationship. All these would have to be sustainable in a planet that behaves like our earth. Just remember that even the earth had to be prepared by early life to come to a state where we became possible. For example oxygen in our atmosphere is a gift of that early life.

This is not to say that there was a conscious attempt to prepare for our arrival. We just happened, that also very recently. Thus a lot will have to happen before mars becomes and autonomous earth like planet. Who knows it might even happen in a few thousand years.