What are incinerator machines? An idiot’s guide

Whether you work in waste management or specialise in medical or farming industries, the responsible disposal of waste is an ongoing challenge. In these industries you’re likely to have come across the terms ‘incinerator machine’ or ‘incineration’.

But what exactly are incinerator machines? What does the process of incineration include, and how do incinerator machines work for different industries?

What is an incinerator machine?

An incinerator machine is a mechanical unit that is built to destroy waste. this happens by burning the waste at an extremely high temperature, reducing it to bottom ash. The machines can be manufactured from small garden waste incinerators, all the way to large scale industrial sized machines.

Waste of all manners is burned until it is reduced to nothing but ash, gas and heat. While many people think gas generated from incineration is harmful for the environment, modern incinerators filter out pollutants meaning only clean air is released from the machine.

Incineration, also known as ‘thermal treatment’, is the process of combustion of organic elements within waste streams. The incineration process requires 3 main elements to work efficiently. These are fuel, heat, and oxygen. There must be fuel to burn for the combustion process to happen. This would be your desired material such as wood or soil. there must be a heat source to start and continue the combustion process. This would be the ignition temperature as once the incinerator is started; the fire will supply it’s own heat. Finally, there must be a sufficient amount of oxygen to start and keep the combustion process active.

Parts of an Incinerator

The parts of most incinerator are quite standard. Some parts can be added during purchase such as air pollution control systems. All incinerators have to have a combustion chamber where the waste is loaded. The majority of incinerators available will now have 2 chambers due to changes in environmental protection regulations.

  • Primary Chamber (Combustion Chamber) – this is where the waste is loaded and ignited. In most incinerators, the ignition occurs due to the high temperatures being retained within the chambers lining.
  • Secondary Chamber – the secondary chamber is sometimes known as the ‘afterburner’ chamber. It is required by law in Europe, USA, Australia and Canada to prevent the formation of harmful particles. In many countries the law stipulates that all flue gas must be resident in the secondary chamber for at least 2 seconds at 850⁰C.
  •  Flue Stack – The flue stack is also known as the chimney. Most incinerators require a stack height of at least 3m. This requirement will be higher in more built up areas or where atmospheric conditions dictate.
  • Control Panel & Thermocouples – These parts of the incinerator control the operation of the machine and ensure the chambers are up to temperature before any waste is loaded for incineration.
  • Burners – Most modern incinerators are fitted with low NOx or modulated gas flow burners.
  • Fuel Tanks – Fuel tanks should be bunded to ensure safe strange of fuel

The Incineration Process

Incineration of waste materials converts the waste into ash, flue gas, and heat. Most waste streams will require some pre-preparation. The incineration process is as follows:

  • Sort – When sorting the waste before incineration, it is important to remove any high value recyclable items for resale.
  • Shred – Normalise the particle size and add air to the mix
  • Dry – Moisture can impact the incineration process and the time it takes for combustion. The energy used for burning the waste will first be used to dry out the material. The waste won’t actually start to burn until it is dry. For this reason, we suggest a max of 30% moisture to ensure best efficiency.
  • Determine batch size – establish the optimum batch size based on the volume you can burn for the lowest cost. It is important not to overfill your incinerator as overfilling the incinerator will cause slow burning of the waste.
  • De-ash – Once the chamber has cooled, you can easily de-ash the incinerator system ready for the next batch of waste.
  • Spot Checks – It is important that regular checks are carried out to ensure that the chamber, burners and fuel lines are all in good condition.
  • Re-load – Load the chamber for the next operation and repeat the process.

Types of Incinerator

There are many different types of waste incinerator designs available. These designs can range from small 75ltr oil drum models, to huge waste to energy plants that take years to construct before they are suitable for operation.

At Inciner8, we specialise in the design and manufacture of direct-flame incinerators alongside moving grate technologies.

The following are different types of incinerators:

Rotary Kiln – A rotary kiln incinerator is designed and manufactured with a rotating combustion chamber that keeps the waste continuously moving. This allows the waste to vaporise for easier burning. A lot of medical waste incinerators use this design of incinerator. Common types of waste that can be processed in a rotary kiln incinerator are:

  • Hazardous Waste
  • Medical Waste e.g. infectious waste, sharps, medical remains, surgical waste, clinical waste, laboratory waste etc.
  • Pharmaceutical waste

Fluidised Bed – Fluidised bed incinerators are mainly used for the treatment of sludge waste. A fluidised bed is typically a sand bed or another granular like material. Air is pushed through it to the point where the sand begins to act like a liquid. The waste then sits on top of the moving sand and is kept constantly moving. This helps the waste to burn quicker as the constant movement exposes more surface area of the waste.

Moving Grate – Moving grate incinerators are typically used for the destruction of municipal solid waste. The moving grate moves the waste through to the combustion chamber. By having the waste constantly moving, it allows air to flow through the waste allowing for quicker combustion and burning of the waste.

Liquid Injection – Liquid injection incineration is the process in which liquid waste is injected directly into the hot gases inside the incinerator. This causes the liquid waste to be mixed in with the heat and gases. This provides instantaneous oxidisation of the injected waste and conversion of pollutants.

Multiple Hearth – A multiple hearth incinerators consists of a number of circular hearths positioned in a column. The waste is fed in through the top of the incinerator and moved in a spiral path across each hearth. When it reaches the bottom it is cooled and discharged as ash.

Catalytic Combustion- Catalytic incinerators are used for destroying gaseous pollutants such as VOCs (Volatile Organic Compounds). These are compounds that can easily become vaporous gases. Catalytic incinerators speed up the oxidation rate, enabling the conversion of pollutants at a lower temperature than some other types of incinerator. This incinerator would be useful when creating a cost effective waste management plan.

Fixed Grate/ Direct- Flame – The fixed grate/ direct flame incinerator is the standard design for an incinerator. it is typically the most commonly manufactured and used. The direct flame is maintained by fuel and oxygen to allow for the combustion of waste.

Why would I need an incinerator machine?

Incineration is a waste management process used all around the world. From America, to Southeast Asia, businesses, farmers and institutions such as colleges and universities, are using incineration to prevent the spread of infection from contaminated waste. This is because it offers a more cost effective and immediate solution compared to other waste management options.

Investing in an incinerator machine, which stays on your premises, allows you to manage your waste very quickly and no longer pay any waste collection costs. It also means you’re playing a part in reducing the amount of material that ends up in landfill, as you’re destroying waste at source.

Different uses for incinerator machines

Medical waste

Medical waste is posing a growing problem worldwide. Medical waste can be generated from various sites. Some of the most common are:

If it isn’t destroyed effectively, it can bring health risks to staff, patients and waste disposal workers. In some cases, members of the public are also at risk due to improper medical waste disposal.

Hazardous materials from these sites can’t simply be discarded. Incinerator machines are the only tool proven to destroy and neutralise medical waste. Around 20-25 per cent of the total waste generated by healthcare establishments is hazardous. Incineration can play a key role in protecting everyone working within that space by destroying the waste on site.

Animal waste

The Department for Environment, Food and Rural Affairs (DEFRA), states that “animal carcasses or parts of animal carcasses suspected or confirmed as infected, must be disposed of by incineration.”

Not disposing of animal waste – including waste, carcases and by-product – can lead to the spread of infection and viruses amongst animals and can also contaminate the food we eat and water we drink. Incineration with the use of an incinerator machine is the only way to guarantee complete bio security.

Inciner8 have many years of experience when dealing with animal biohazards. Our products are developed for rapid disposal of infected animals over a wide area to reduce cross contamination.

General waste

‘General’ types of waste that don’t fall under specific categories like animal or medical, can include waste generated from sites such as military operations, mining operations, small communities, remote housing estates or even boarding schools. It is waste that is not typically harmful, but which needs to be destroyed to minimise its environmental impact.

Our range of incinerator machines are specifically designed to deal with general or specialised waste. If you need more advice on whether investing in an incinerator machine would be worthwhile for you and your organisation, please get in touch with one of our experts today.

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