Abstract:
This century can be called “Plastic age”, plastics play a major role in our modern life, plastic was alternative for most industrial materials due to its fabulous properties, there is an increase in the production and consumption of plastics day by day, the quantum of solid waste is increasing due to increasing in population, developmental activities, and changes in life style.
All plastics need to be disposed after their usage, as waste. The need to manage this waste from plastic becomes more essential for the environmental concern.
This project aims to participate in minimizing the impact of plastic waste on environment by converting it into beneficial fuel, to achieve this objective a device was designed and constructed to crack the plastic waste using two methods: thermal, and catalytic cracking, the device was a fixed bed reactor provided with condenser, receiver, and a safety bubbler.
A sample of 1 kg of LDPE was examined using the two methods, thermal cracking was heated to 540°C, the reaction time was about 70 minutes, it produced a dark black liquid fuel with yield of 55.1% and a conversion of 67.04%. Whereas the catalytic cracking was heated up to 500°C, the reaction time was about 50 minutes, it produced a clear yellow liquid fuel with yield of 61.24% and conversion of 77.41%.
The resulted products from LDPE catalytic and thermal cracking were mostly similar to the specifications of diesel and gasoline respectively.
Other types of plastics were experimented only using catalytic cracking, HDPE, PP, and PS has given yields of 62.78%, 44.10%, and 42.30% respectively. And conversions of 78.98%, 72.10%, and 70.00% respectively.
Due to its fabulous properties, plastic plays an important role in almost every aspect of human’s lives. Most products or tools used involve plastic or were manufactured from plastic such as bags, covers, toys, etc. The widespread use of plastics demands proper end of life management.
The quantum of solid waste is ever increasing due to increase in population,developmental activities, changes in life style, and socio-economicconditions, Plastics waste is a significant portion of the total municipalsolid waste (MSW). The environmental hazards due tomismanagement of plastics waste include the following aspects:
o
Littered plastics spoils beauty of the city and choke drains and make
Important public places filthy;
o
Garbage containing plastics, when burnt may cause air pollution by
emitting polluting gases;
o
Garbage mixed with plastics interferes in waste processing facilities
and may also cause problems in landfill operations;
o
Recycling industries operating in non-conforming areas are posing
unhygienic problems to the environment. [1]
It is estimated that 200 million tones of plastic are produced each year and less the 3.5% is recycled. The world plastic production is increasing at 3.5% per year. This means every twenty years the amount of plastic we produce doubles. [2]
Plastic waste affects our environment , it cause pollution to the oceans , garbage has been discarded into the oceans for as long as humans have sailed the seven seas or lived on seashores or near waterways flowing into the sea. Plastic also affect the landscape, once they are used, most plastic bags go into landfill, or rubbish tips. Each year more and more plastic bags are ending up littering the environment. Once they become litter, plastic bags find their way into our waterways, parks, beaches, and streets. And, if they are burned, they infuse the air with toxic fumes. Notes that the decomposition of plastic bags takes about 1000 years [3].
There are three main methods that used to dispose the plastic waste around the world which is:
1) Plastic Biodegradation in Landfills
2) Reduced Use and Recycling
3) Burning Plastic
All the previous methods have their advantages and disadvantages, humans started to deal with waste by burning, then by dumping, and now recycle is used. But the main point is not only get rid of plastic wastes; it’s how possible to exploit as much as possible.
The new method strategy is to convert waste plastic into fuel, this requires feedstock’s which are non hazardous and combustible. In particular each type of waste plastic conversion method has its own suitable feedstock. The composition of the plastics used as feedstock may be very different and some plastic types might contain undesirable substances (e.g. additives such as pigments, plasticizers, fillers, and etc) which pose potential risks to humans and to the environment, these additives will remain as residues mixed with the long chain carbons, and can be used for further applications according to the residues’ properties.
So to overcome the abundance plastics waste problem and also to increase its economic value the convert of plastics waste into fuels using catalytic cracking process is one of the most economic methods used.
By this process, plastic can be converted into monomers, fuels, and chemicals, despite of that, fuels from chemical recycling process also can be used as alternative energy, replacing natural gas and crude oils.
The process is really simple, if plastic waste heated in non oxygen environment in the presence of catalyst; it will melt, but will not burn. After it has melted, it will start to boil and evaporate, the out coming gas is then run through a condenser which reduces the temperature to liquefy the gas and some of the vapors with shorter hydrocarbon lengths will remain as a gas.
This process has a lot of advantages such as:
o
Available raw material, (waste plastic).
o
A good quality fuel.
o
Simple system.
o
Low operating cost.
o
Safe & environmentally friendly process.
o
Doesn’t require accurate separation
AlkaZadgaonkar, who lives and works as an applied chemistry professor in the central Indian town of Nagpur, began to work her magic almost 2 years ago. A zero pollution industrial process to convert non-biodegradable - and mostly non-recyclable plastic waste into liquid hydrocarbons is quietly underway in the Butibori industrial estate.
After that the world started to think in this strategy to convert plastic wastes into a very useful fuel so many companies appear in the world. [4]
In March of 2008, GPI completed their first production prototype that is said to be capable of processing 100 tons of municipal and other waste per day in a low heat and low pressure, proprietary catalytic system, converting the feedstock into high grade fuel, including diesel, kerosene, and fuel oil; as well as electricity and an asphalt component. [5]
The idea of this innovation is to find a suitable yet cheap solution for the increasing problem of plastic waste, which is to manufacture a device that produces fuel from plastic waste;that can be used in many applications. This method provides a great solution for the problem of waste, and also the problem of decreasing fossil fuels that are extracted from underground because fossil fuels are expensive and non-renewable source of energy, the world needs a solution to that problem and this is the solution.