What is Pyrolysis?

Pyrolysis is a thermochemical process that turns waste into useful resources. Materials such as biomass, plastics, tyres, or sludge are heated in the absence of oxygen and broken down into valuable products such as fuels or oils, syngas, and biochar. Unlike burning, pyrolysis reduces harmful emissions and offers a sustainable way to recover energy from waste.

How does pyrolysis work?

Pyrolysis chemically breaks material down in accordance with its chemical structure. The fixed carbon and ash content of the materials will remain as solid, whereas the volatile content of the materials will be released as a gas mixture.

• The solid product is known as char or biochar

• The gas product is known as syngas

• The condensable part of the syngas is known as pyrolysis oil or tars

The higher the temperature of the pyrolysis, the more chemical breakdown of the material will occur resulting in a more stable biochar and the less condensable portion of the syngas that will be produced giving a richer syngas.

This is the basis of Anergy High Temperature Pyrolysis (HTP) which is to operate at a higher temperature as compared to conventional pyrolysis 

The Pyrolysis Processes

The general pyrolysis process utilising Anergy’s HTP can be described as follows:

1. Feedstock preparation

Feedstock is loaded into a feed bin equipped with a sealing rotary valve to maintain an oxygen starved condition and transported via a conventional feed screw into the pyrolysis unit.

2. Feedstock into Char

In this process, feedstock is slowly heated in a rotating heat tube using indirect heat from gas burners. With no oxygen present within, the material does not burn and instead is thermally broken down into char and unrefined syngas. Char product is cooled and collected.

3. Syngas cleaning 

Unrefined or raw syngas from the pyrolysis process contains impurities in the form of inorganics, dust and tar which are removed in the cleaning process prior to utilising the syngas for the intended applications.

Pyrolysis Applications

Pyrolysis can be applied to various types of waste. The following are the more well-known process pyrolysis applications.

Biomass Applications

Taking advantage of the pyrolysis process, biochar can be produced from biomass. In addition, energy in the form of heat or electricity or other fuel types can also be produced from the pyrolysis of biomass. 

Biomass is also considered as a renewable energy source and it can be used to replace fossil fuel consumption. In addition the biochar produced can also be sequestered into the ground as part of the carbon sink. This will help in the effort for a cleaner and greener environment.

Plastic Applications

There is a massive issue in dealing with plastic waste as they are considered non-degradable. They will not be broken down naturally such that it will keep piling up in landfills. 

Dealing with plastic waste through pyrolysis helps to break down the plastic waste and at the same time extract the energy from it to be converted into useful products such as for heat, electricity or fuel.

The benefits of Pyrolysis

Pyrolysis is one of the thermochemical processes available to process waste and convert it into useful energy. Others include gasification and incineration.

Waste into resource

Through pyrolysis, waste is no longer seen as a disposal problem but as a valuable resource for Anergy’s HTP process. Organic materials such as solid waste, plastics, and biomass can be thermochemically broken down into syngas, bio-oil, and biochar. 

These products serve as valuable and some even renewable sources of energy, which effectively closes the loop between waste generation and resource recovery. 

By converting discarded materials into energy and useful by-products, pyrolysis supports a circular economy, reduces dependence on fossil fuels, and helps communities derive value from materials that would otherwise contribute to landfill accumulation.

Environmentally friendly waste management

Pyrolysis offers an environmentally sustainable alternative to conventional waste treatment methods like landfilling and incineration. 

Since Anergy’s HTP operates in the absence of oxygen and at higher temperatures, it significantly reduces harmful emissions. As an added benefit, the process also diverts waste away from landfills by virtue of utilisation as a resource. 

Additionally, by producing clean syngas and stable biochar, pyrolysis transforms the environmental burden of waste into renewable energy opportunities.

Carbon Sequestration

The absence of oxygen in the process allows biochar to be produced.

The oxygen that is present in gasification and incineration will consume and oxidise the fixed/organic carbon content of the material to maintain the high operating temperature.

The biochar produced from the pyrolysis process can be sequestered. The sequestration of biochar slows down the release of greenhouse gases into the environment. The biochar is able to hold the carbon, that would otherwise be released as greenhouse gases, for thousands of years.

Undiluted Syngas Production

Oxygen for the gasification and incineration generally comes from the environment which contains 78% nitrogen.

The inert nature of nitrogen will dilute the syngas from the gasification and incineration processes such that it has lower calorific value as compared to syngas from pyrolysis process.

Anergy and Pyrolysis

Pyrolysis is a process that can be helpful in creating a cleaner and greener environment. Pyrolysis is able to produce biochar that can be sequestered as carbon sinks and at the same time it is able to produce energy in the form of heat, electricity or other fuel.

Anergy is performing pyrolysis at a higher temperature such that it allows a more thorough chemical breakdown of the materials such that the products produced from Anergy’s HTP are of superior quality. 

If you are a business looking into the applications of Pyrolysis, be sure to contact our team, today.

 

 

Frequently Asked Questions

How does Pyrolysis remove carbon?

Pyrolysis does not remove carbon per se, but it stabilizes and stores it in the form of biochar rather than releasing it into the atmosphere as carbon dioxide. The process itself is still releasing greenhouse gases, but the source can come from renewable energy sources such as biomass. The biochar that is produced from biomass is considered a carbon-negative process.

What is pyrolysis in biochar?

Pyrolysis is a process required in producing biochar. The absence of oxygen in the process prevents any oxidation of the solid product, such that biochar can be formed. 

Other thermochemical processes, such as torrefaction, gasification, and incineration, are unable to produce any biochar. 

In the case of torrefaction, the biochar is not stable enough to be a carbon sink as it can combust easily. As such, it is generally used as solid fuel. In the gas of gasification and incineration, the oxygen that is injected into the process will oxidise the char such that the remaining solid product is mostly ash. 

Is pyrolysis just burning?

No, pyrolysis is not the same as burning. 

Although both processes involve heating, burning requires oxygen and converts matter into carbon dioxide, water, and heat (depending on the degree of completeness for combustion). 

On the other hand, pyrolysis occurs at a high temperature to allow the matter to thermochemically break down in the absence of oxygen into useful products such as syngas and char. This process allows the recovery of valuable resources and at the same time minimises the impact of wastes and harmful emissions to the environment. 

Is pyrolysis the same as gasification?

No, pyrolysis is not the same as gasification.

Both processes are thermochemical processes, but they are fundamentally different. 

Pyrolysis is a process in the absence or limited oxygen environment, whereby gasification involves the injection of oxygen or air into the process. 

This difference is significant, such that the products from both processes are very different. Biochar can only be produced from pyrolysis. 

On the syngas side, while both are producing syngas, the injection of air introduces inert nitrogen into the syngas mix such that it is diluted, unlike in pyrolysis. 

As such, in converting to electricity, steam turbines are generally used in gasification, whereas in pyrolysis, gas engine generators can be used. 

Similarly, it is unheard of that syngas from gasification can be used to sustain its process, which can be the case for pyrolysis. 

This is mainly due to the diluted syngas from gasification, such that the syngas combustion is not yielding enough energy to sustain the process.