Plastic Pyrolysis: A Beacon of Hope to Get Rid of Plastic Waste

Plastic waste is a global environmental problem
Plastic waste is a global environmental problem

I. Introduction

The global consumption of plastic products is increasing year by year. And with it, the volume of plastic waste is rapidly but steadily increasing.

Plastic waste has become a global environmental crisis, with unprecedented amounts of waste polluting our land, waterways, and oceans.

The detrimental effects of plastic pollution on ecosystems, wildlife, and human health are becoming increasingly evident. 

What to do with mountains of plastic waste? One such method is pyrolysis. Plastic Pyrolysis refers to the process of plastic decomposition under the influence of high temperatures and in the absence of oxygen.

Plastic pyrolysis involves subjecting plastic waste to high temperatures, causing it to break down into pyrolysis oil, gas, and residue.

With careful optimization, this process has the potential to significantly reduce plastic pollution while simultaneously creating valuable products.

In this article, we explore the vast potential of plastic pyrolysis as a sustainable waste management solution. We will look into the process, highlighting its benefits and applications.

By harnessing the power of pyrolysis, nations can pave the way toward a cleaner, greener future where plastic waste is no longer a burden but a valuable resource waiting to be utilized.

II. Methods for the disposal and recycling of plastic waste

The main methods of handling plastic waste can be divided into 4 groups:

Mechanical processing (recycling)

Chemical Disposal

Burial

Thermal methods (incineration, pyrolysis)

The mechanical method (recycling)

Granulation is a mechanical technique that can be used to process materials including waste film, polycarbonate, low-pressure polyethylene, expanded polystyrene, polyamide, and others.

The method consists of heating, passing through an extruder, granulating, and cooling. The pellets can then be reused in the production of plastic goods.

The disadvantage of this method can be considered the fact that only lower-quality plastic products can be made from recycled materials.

Chemical disposal 

involves the use of toxic solvents, which also fail to “recreate” plastic of the original quality. 

In addition, any chemical process is critically dependent on the homogeneity of raw materials, which is difficult to achieve with regard to waste. Sorting facilities are needed.

Burial:

Even discussing the benefits and drawbacks of a practice like burial is not entirely suitable.

This is the method of the day, unfortunately, widespread today due to the relative cheapness of the present moment. But in the near future, it will play out with much worse dangers than other methods.

Thermal methods (incineration, pyrolysis)

subdivided into incineration and pyrolysis, are also widely used for the recycling of plastics. 

Advantage of incineration– in its “omnivorous” and reduction of the initial volume of waste, especially in relation to plastics that have a considerable calorific value (of course, the calorific value of different types of plastic is radically different).

Given a high-quality modern gas cleaning system, incineration is widely used today, for example, Germany burns up to 60% of its plastic waste.

A surge in plastic incineration was observed from 2000-2016 in Europe, where the amount of plastic burned increased by 61%.

There are 231 large waste incineration plants in China and, accordingly, the share of incineration there is also high.

However, the senseless waste of a fairly valuable secondary resource is not permissible today.

Pyrolysis

involves the heating of raw materials without access to oxygen and the decomposition of polymer chains without their oxidation.

 This is a rather promising method, which, to a lesser extent than incineration or chemical recycling, which burdens the environment, has one Achilles’ heel – low productivity.

Almost all pyrolysis systems on the market today still operate on a periodic or semi-continuous basis, which is associated with difficulties in closing the process.

III. Pyrolysis of plastic 

Pyrolysis is a process of thermochemical destruction of plastic waste at high temperatures without air access.

As a result, plastic waste is decomposed into simpler molecules, which can then be used in various industries.

The pyrolysis process takes place in special reactors. Plastic waste is loaded into them, where it is heated to a temperature of 300–800 °C. At this temperature, plastic decomposes into its components: gases, oils, and carbon.

The resulting products pass through a cooling system where they condense back into liquid form. The solid residue is discharged from the reactor.

The resulting substances are used as fuel. They can be used to generate electricity, heat, get fuel for cars and other mechanisms, as well as for the production of other chemicals.

IV. Actual steps involved in plastic pyrolysis

A. Pre-pyrolysis: 

1. Plastic waste shredding:

In this step, the plastic waste is shredded into smaller pieces or granules.

Shredding increases the surface area of the plastic, making it easier to handle and promoting efficient heating during the pyrolysis process.

2. Plastic waste drying:

Before undergoing pyrolysis, the shredded plastic waste needs to be dried to remove any moisture content. Moisture can interfere with the pyrolysis reaction and affect the quality of the end products.

Drying is typically achieved by subjecting the shredded plastic to heat or using a drying mechanism.

3. Plastic waste preprocessing to separate non-plastics:

This step involves the separation of non-plastic components from shredded plastic waste.

Non-plastics, such as paper labels, metals, and other contaminants, are removed to ensure that only plastic materials are processed in the subsequent steps.

Various techniques like sieving, magnetic separation, and density-based separation can be employed for this purpose.

B. Pyrolysis

4. Pyrolysis:

The shredded and preprocessed plastic waste is fed into a pyrolysis reactor, where it undergoes the pyrolysis process.

Pyrolysis involves the application of heat in the absence of oxygen, causing the plastic molecules to break down into smaller molecules.

This results in the formation of pyrolysis oil, pyrolysis gas, and pyrolysis residue.

The specific temperatures and conditions in the reactor can vary depending on the type of plastic and the desired product yields.

5. Pyrolysis Oil Distillation & Purification:

After the pyrolysis process, the pyrolysis oil is typically subjected to distillation and purification to remove impurities and separate them into different fractions.

Distillation helps separate the oil into various components with different boiling points, such as gasoline, diesel, and heavy oils.

Purification processes like filtration and chemical treatments may also be employed to improve the quality of the pyrolysis oil.

6. Pyrolysis Oil Storage and Dispatch:

The final step involves storing the processed pyrolysis oil in appropriate storage tanks or containers.

The oil can be further transported or dispatched for various applications such as fuel, feedstock for other chemical processes, or further refining.

One of the advantages of pyrolysis is that it allows you to process a wide range of plastic waste, including those that are difficult to recycle. 

In addition, pyrolysis can be implemented locally – localized at enterprises and in areas where plastic waste is generated, which reduces the cost of their transportation.

V. Types of plastic pyrolysis plants

Plastic pyrolysis plants are specialized devices designed for the pyrolysis processing of plastics. 

Depending on the design and purpose, several types of such installations can be distinguished:

 

1. Continuous pyrolysis plants.

They work non-stop, continuously processing plastic waste and giving out ready-made pyrolysis products.

Such plants can be automatic or semi-automatic and are used for the industrial processing of large volumes of plastic waste.

The optimal solution for enterprises of various sizes is a continuous pyrolysis rotary kiln, which is characterized by high efficiency and fast self-sufficiency.

2. Mobile ovens for pyrolysis.

These are plants consisting of a mixing chamber in which plastic waste is mixed with catalysts and then pyrolyzed in a sealed oven.

They are small in size and can be used for both industrial and small-scale plastics processing. This is explained in the following section. 

3. Vertical and horizontal retorts.

These are installations in which pyrolysis takes place in a vertical or horizontal reactor – a retort.

In a vertical reactor, materials are loaded from above, and pyrolysis products exit from below.

In a horizontal reactor, materials are loaded from one end, and pyrolysis products exit from the other. Vertical and horizontal reactors can be used for industrial and polymer processing.

4. Installations for pyrolysis with a liquid phase.

These are plants in which plastic waste is pyrolyzed in the presence of a liquid phase such as oil or water.

They can be used to process various types of plastic waste, and are highly efficient and environmentally friendly.

In terms of design, plastic waste pyrolysis plants include

(1) a furnace with a retort, (2) a system for loading and unloading materials, (3) a system for monitoring and controlling the process, (4) collecting products, and (5) cleaning gas emissions.

The size of the plants and their performance can vary depending on the requirements and needs of companies.

Plastic pyrolysis converts plastic waste into pyrolysis oil, gas, and residue.

The typical yields from plastic pyrolysis depend on the grade of the plastic waste and include:

Pyrolysis oil ranges from 50 to 80 percent, depending on the kind and amount of plastic in the waste plastic.

Pyrolysis gas ranges from 20 to 35%, depending on the kind and amount of plastic in the waste plastic.

Pyrolysis residue can range from 3% to 30%, depending on the amount of ash and dirt in the plastic waste.

Wastewater will be produced if the plastic trash has any moisture in it.

VI. What is catalytic pyrolysis technology?

 

 Catalytic pyrolysis technology can pyrolysis waste tire/plastic
Catalytic pyrolysis technology can pyrolysis waste tire/plastic (Courtesy: https://www.wastetyreoil.com)

 

In recent years, catalytic pyrolysis has emerged as an advanced waste treatment technology.

Scientists discovered in the 1990s that incinerating trash produces a highly hazardous human carcinogen called Tetrachlorodibenzo-p-dioxin.

To prevent secondary pollution, Western industrialized nations have invested heavily in developing innovative garbage disposal equipment.

Environmental experts agree that pyrolysis technology offers a new approach to waste reduction, recycling, and safety.

The theory of catalytic pyrolysis technology

Catalytic pyrolysis technology and incineration are two distinct procedures. Incineration is exothermic, while pyrolysis requires heat absorption.

The primary byproducts of incineration are carbon dioxide and water.

In catalytic pyrolysis technology, organic waste undergoes thermal instability under anaerobic or anoxic conditions.

This causes the waste to crack and condense, forming new gases, liquids, and solids. Fuel oil and combustible gas can be extracted from this process.

Catalytic pyrolysis technology involves heating organic molecules and breaking them into smaller molecules.

This process encompasses various physical and chemical processes. Simply put, it’s the essence of catalytic pyrolysis technology.

VII. Benefits and disadvantages of pyrolysis

 

Fuel oil extracted from waste plastic using plasic pyrolysis process

Fuel oil extracted from waste plastic using a plastic pyrolysis process (Courtesy:https://www.wastetyreoil.com)

 

1. High efficiency

The pyrolysis technique is suitable for all types of plastic waste, whether clean, unwashed, or unsorted. Shredding is not required in a batch waste plastic pyrolysis plant.

The waste pyrolysis reactor and its accessory system handle all operations, from plastic breakdown to fuel oil production. This approach is practical and labor-saving.

2. High profit

Waste plastics such as PE (polyethylene), PP (polypropylene), PS (polystyrene), and ABS, among others, have greater oil yields above 50%.

This indicates that from the above 10ton waste plastic, you may extract at least 10ton x 50% = 5-ton pyrolysis fuel oil.

This project is certainly profitable because it involves a way to turn garbage into fresh energy.

3. Other benefits

With the use of this technology, it is possible to create valuable and popular goods out of waste plastic, most notably fuel oil, diesel, and heating oil.

The possibilities of pyrolysis are not limited to these kinds of goods. It is also achievable to obtain hot gas for boiler houses of thermal power plants with the use of a pyrolysis reactor.

To accomplish this, you will need to slightly alter the technological procedure previously mentioned, stopping it at the point where plastic changes from a solid state to a gaseous state.

By using pyrolysis, it is feasible to eliminate 99% of the dangerous components that go into making plastic. It is one of the methods for recycling that is least harmful to the environment.

 VIII. Disadvantages of pyrolysis: 

1. Environment problem

The main disadvantage of pyrolysis technology is reflected by the waste pyrolysis plant. Technology is very good, but you need to be careful to choose the right pyrolysis plant supplier.

An unqualified waste plastic pyrolysis plant does not meet environmental emission standards and will cause air and soil pollution, which will decide if you are able to continue this project in your local area. 

 

Pollution produced by an unqualified waste plastic pyrolysis plant
The pollution produced by an unqualified waste plastic pyrolysis plant (Courtesy:https://www.wastetyreoil.com)

 

2. Project Permit

Since using pyrolysis technology to convert plastic into oil belongs to a chemical project, so to get a permit is necessary for you to do such a project in your place legally.

It will take time and effort, but different areas have different policies. For more information, you are welcome to check with us.

In a nutshell, the advantages of using pyrolysis technology to convert plastic to oil outweigh its disadvantages, the most important thing is to get a qualified waste pyrolysis plant from a good supplier.

During the operation of the pyrolysis reactor, a sufficiently large amount of harmful chemical compounds is released.

In principle, if the equipment is properly equipped with a filtration and purification system, this factor should not be a serious problem. Quality equipment for pyrolysis is quite expensive.

 To organize the process of operation of the pyrolysis reactor in accordance with all the rules, serious financial investments are required, which not all companies can afford.

FAQs

What is the difference between plastic pyrolysis and plastic recycling?

Plastic recycling involves the process of transforming plastic waste into new plastic products through sorting, cleaning, and reprocessing. It typically requires the plastic waste to be of high quality and relatively homogeneous.

On the other hand, plastic pyrolysis is a thermochemical process that converts plastic waste into pyrolysis oil, gas, and residue through the application of heat in the absence of oxygen.

Unlike recycling, pyrolysis can handle a broader range of plastic waste, including mixed and contaminated plastics, which are challenging to recycle.

How does plastic pyrolysis contribute to a circular economy?

Plastic pyrolysis contributes to a circular economy by enabling the conversion of plastic waste into valuable resources.

Instead of discarding plastic waste or relying solely on traditional recycling methods, pyrolysis allows for the recovery of energy and materials from plastic waste that would otherwise end up in landfills or incinerators.

The pyrolysis products, such as pyrolysis oil, can be used as a substitute for fossil fuels, while pyrolysis gas can be used for heat and power generation.

Additionally, the carbon-rich pyrolysis residue can be utilized in various applications, such as construction materials or carbon black production.

Is plastic pyrolysis a safe process?

Plastic pyrolysis, like any industrial process, requires proper safety measures and equipment to ensure safe operation.

The heating of flammable materials during pyrolysis poses potential hazards if not managed correctly.

Reputable pyrolysis plants incorporate safety features and follow strict protocols to minimize risks.

Companies like APChemi emphasize safety as a key performance indicator and offer standardized pyrolysis plants designed for robust and safe operation.

It is important to adhere to safety guidelines, train personnel, and implement comprehensive safety protocols to ensure the safe implementation of plastic pyrolysis technology.

What are the challenges associated with plastic pyrolysis?

Plastic pyrolysis faces several challenges that include the varying quality of plastic waste, which affects the yield and quality of pyrolysis products.

The presence of contaminants, moisture, and non-plastics in the waste stream can impact the process efficiency and product outcomes.

Additionally, scaling up pyrolysis operations and achieving economic viability can be challenging due to the initial investment costs, energy requirements, and market demand for pyrolysis products.

However, technological advancements, process optimization, and supportive policies can help overcome these challenges and improve the effectiveness and efficiency of plastic pyrolysis.

What types of plastic waste can be processed through pyrolysis?

Pyrolysis technology can process a wide range of plastic waste. That includes post-consumer plastics, municipal solid waste segregated plastics, rejected plastics from mechanical recycling, multi-layer packaging, and mixed PET/PVC-contaminated plastics.

The flexibility of pyrolysis plants allows for the processing of various forms of plastic waste, including solids, semisolids, waxes, and liquids.

This versatility enables the utilization of different feedstock compositions, including plastic, tires, biomass, and waste oils, all within the same pyrolysis reactor.

What are the end-products generated from plastic pyrolysis used for?

Plastic pyrolysis generates several valuable end-products. Pyrolysis oil can be used as a substitute for fossil fuels in industrial applications, power generation, or as feedstock for further refining processes.

The pyrolysis gas produced can be utilized for heat and power generation, reducing the reliance on traditional energy sources.

The carbon-rich pyrolysis residue, also known as char, can be used as a solid fuel or as an additive in construction materials.

Additionally, some pyrolysis processes can recover carbon black, a valuable material used in the manufacturing of tires, rubber products, and other industrial applications.

These end-products contribute to resource recovery, energy production, and the reduction of greenhouse gas emissions.

IX. Conclusion 

 Plastic pyrolysis technology presents a promising and sustainable solution for effectively managing plastic waste.

By converting plastic waste into valuable products, such as pyrolysis oil, gas, and residue, pyrolysis offers numerous environmental, economic, and social benefits.

Plastic pyrolysis addresses plastic pollution, reducing waste in landfills, oceans, and ecosystems. It transforms plastic waste into resources, conserving natural resources and reducing carbon emissions.

The economic potential is significant. Demand for pyrolysis products, like oil and carbon black, is growing in the energy, chemicals, and construction sectors, creating revenue and jobs.

Pyrolysis plants provide decentralized waste management, cutting transportation costs and fostering local development. It offers an alternative to landfilling and incineration, which harm human health.

In summary, plastic pyrolysis technology demonstrates the potential to transform the plastic waste crisis into an opportunity.

Through technological advancements, supportive policies, and market developments, plastic pyrolysis can play a vital role in achieving a more sustainable and circular economy, where plastic waste is seen as a valuable resource rather than a burden.

 

Share On
Sunil Kirloskar
Sunil Kirloskar

Hi, I am Dr. Sunil. My present blog greenappleplanet.com mainly focuses on various aspects of environment, green living, green technology, solutions to various areas towards preservation of the planet-our mother earth. Blog articles revolve around environment protection at its core. I am sure the young environmentalists will be inspired through these articles. This bog is dedicated to those working for achieving sustainable enviroment and living.

Articles: 17

3 Comments

  1. Hi there, I just came across your new site and saw that you’re getting started with WordPress – something I’m well experienced in! It’s always thrilling to see how new websites unfold. Building a website is not always a simple task – are you doing this on your own or do you have a developer to help you out? Regardless, I can’t wait to see how your site progresses. If you ever need to discuss anything WordPress-related, feel free to drop me an email at contact@ghazni.me, or message me on WhatsApp or Telegram.

    Kind regards,
    Mahmud Ghazni
    WhatsApp: +880 1322-311024
    Telegram: https://t.me/ghaznidev

  2. Amazing blog! Do you have any suggestions for aspiring writers?
    I’m planning to start my own site soon but I’m a little lost on everything.

    Would you recommend starting with a free platform like WordPress or go for
    a paid option? There are so many choices out there that I’m completely confused ..
    Any recommendations? Bless you!

Leave a Reply

Your email address will not be published. Required fields are marked *