What happens to the used cooking oil you recycle?

Forth Road Bridge

Ever thought about what happens to the used cooking oil collected from your hotel, restaurant, café or other professional kitchen?

A licensed waste cooking oil collector will make sure all your used cooking oil is refined into biodiesel – a green fuel helping to reduce lower greenhouse gas emissions for diesel vehicles on the roads.

Every litre of used cooking oil we collect is used to make a litre of biodiesel – in turn displacing a litre of fossil fuel diesel.

Your oil goes through several processes before it can become biodiesel – from grading, cleaning and filtering to the chemical reaction transesterification.

Here’s how it works:

Once your driver has loaded the oil onto our lorry and handed over your waste transfer note, the oil is transported to our recycling unit in Southall, west London.

At Proper Oils HQ

Proper Oils Mitsubishi Canter cooking oil collection and delivery trucks new livery designs

Here all our waste cooking oil must be cleaned and filtered to a tight specification before it is ready for the biofuel refineries.

First, our yard team check and grade your oil for quality. We look at the clarity and colour of the oil as this will determine how long it needs to stay in each stage of the recycling.

Next, we start cleaning it, pouring the oil into a large square tank topped with a metal grid – our pre-filtration system. The grid acts rather like a sieve, catching food and any other debris, which is removed for recycling.

Meanwhile, inside the tank, the oil is heated to make it more viscous, allowing any smaller debris, water and impurities to sink to the bottom so they can be separated.

We are also able to recycle solid animal fats, which are melted in a separate tank, and undergo the same process.

All the oil is then piped into our large filtering system, where it’s finely filtered until it meets the exact specifications of the biofuel refineries.

Once we are happy that the oil has been recycled correctly, it is transferred to our bulk storage tank. This is emptied every few days into an oil tanker from a biofuels refinery, like Greenergy. The tanker collects 26.5 tonnes of used cooking oil each time.

Transporting the oil to Greenergy

Next stop: a Greenergy biodiesel refinery in Teeside or Humberside. Each of these plants processes about 20 tonnes of used cooking oil every hour, 365 days a year.

On arrival at the plant, a Greenergy technician draws a sample of oil from the tanker for testing in a laboratory. This is to check that the oil meets their specifications.

Once approved, the oil moves through the plant via a complex network of pipes and pumps for further purification in centrifuges and a distillation unit.

Conversion to biodiesel

Finally, it reaches a chamber fitted with beaters – think ‘giant blender’, and you’re on the right lines.

This is where the oil is mixed with methanol and potassium hydroxide in the chemical reaction that turns the cooking oil into biodiesel. This is called transesterification. The blending action ensures every molecule of oil reacts with the methanol and potassium.

Each litre of biodiesel produced results in 91% lower greenhouse gas emissions than a litre of fossil fuel diesel, according to Greenergy.

All the petrol and diesel sold in the UK has, by law, to include a ratio of 4.75% biofuel to help reduce greenhouse gas emissions.

To create this 4.75% blend, Greenergy transports the finished biodiesel to diesel tanks in Teeside or near London, and mixes them to their formula. The resulting diesel, known as B7, is collected by tankers and distributed to garage forecourts across Europe, helping to keep the road and rail network moving.

What was once considered a waste product in your kitchen has been transformed into a greener fuel and natural resource, reducing greenhouse gas emissions for the whole country.

To book a used cooking oil collection, or find out more about Proper Oil’s services, please call us on 0208 894 9476, email info@properoils.co.uk or simply fill in our form.

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Read more:

Why we’re working with Considerate Hoteliers
6 ways our new bins could help your waste cooking oil collection
6 problems you may have with your used cooking oil storage – and how to fix them
10 years of waste cooking oil collections with Proper Oils


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