Green Gold – Transforming the UK’s Used Cooking Oils into Premium Biodiesel

Charlotte Miller

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Biodiesel production from sustainable transport fuel sources such as UCO is an integral element of sustainable fuel development. UCO provides a readily accessible lipid raw material source which doesn’t conflict with food chains and comes free from unwanted contaminants – essential requirements in creating environmentally-friendly transport fuels.

How It’s Done

Used cooking oil (UCO) that we collect is sent directly to our state-of-the-art bio refinery, one of the largest facilities in the UK solely dedicated to processing UCO. Here it undergoes a series of reaction, separation and refining processes designed to produce high quality biodiesel fuel without modification to engines or ignition systems; plus it can even be blended seamlessly with fossil diesel without loss in performance.

UCO cannot be recycled back into human or animal food chains due to safety concerns; therefore biodiesel production is the most sustainable solution for disposing of this waste material. Transesterification is used as the process for this conversion; during which oil is heated, filtered and combined with alcohol (usually methanol) and catalyst to form an ester which then separates into biodiesel and glycerol products.

Biodiesel differs significantly from traditional diesel, which is a fossil fuel and thus emits carbon dioxide when burned, by emitting greenhouse gas emissions only when its source vegetable or animal fat grows. Its environmental footprint is far less damaging as it doesn’t contain any sulfur nor pollute groundwater supplies like its petroleum-based counterparts do.

Biodiesel can be produced from vegetable oils, animal fat/oil/tallow or waste vegetable and cooking oil. Commercial production like that done at Syntech usually relies on oil crops such as rapeseed or palm but this places undue stress on land needed to grow food. This explains why most biodiesel production in the UK currently comes from waste vegetable oil production.

Biodiesel fuel used in a diesel engine produces significantly less pollution than its fossil counterpart, and causes far less environmental damage if spilled as it degrades quickly and is non-toxic. Biodiesel is also much safer to handle due to its higher flashpoint that resists ignition and explosions.

Biodiesel helps us become less dependent upon fossil fuel reserves that are quickly diminishing and the global politics surrounding their acquisition. Producing it sustainably from domestic resources reduces greenhouse gas emissions while simultaneously saving on our dependence on foreign imports.

Biodiesel production is more eco-friendly than drilling and refining of conventional fossil fuels, as its production uses vegetable and animal fats rather than toxic by-products produced during fossil fuel extraction processes. Conventional oil drilling, for instance, is known to produce surface and atmospheric pollution and has even caused explosions on poorly managed wells.

For example, one such well erupting into the Gulf of Mexico released 1 Million Barrels into it in 2010. By comparison, biodiesel comes from vegetable or animal oils, and produces much fewer toxic by-products during production than fossil fuel extraction processes do.

The Process

Oil undergoes a series of chemical reactions when combined with alcohol (usually methanol) to form glycerol and biodiesel; this process is known as transesterification, and its products can then be used to create renewable diesel and heating oil products.

Heat is applied to raw materials at temperatures ranging between 140 and 180 degrees Celsius to speed up reaction rates and enhance formation of esters desired for production, while also eliminating the need for toxic solvents that would normally be necessary in this process.

UCO requires more stringent transesterification conditions ( due to its higher content of free fatty acids; however, methanol can mitigate this impact.

To achieve optimal reaction conditions, an acid pretreatment process is often utilized. This involves adding acid catalyst and alcohol in order to lower fatty acid levels; though this step may be costly it does improve product quality while decreasing side reactions.

Once pre-treatment of oil has been completed, it can then be combined with various feedstocks and subjected to transesterification reaction. The proportion of UCO within this mixture will depend on its composition; typically up to 20%. Reaction can either be carried out discontinuously or continuously.

SAF (stratified aviation fuel) is used by commercial flights around the world as an alternative to jet fuel; however, those made from UCO could potentially contribute to deforestation as countries which harvest palm oil will export some of it as SAF to meet global demand, according to research by green campaign group Transport & Environment.

The End Product

Used cooking oil is taken to our state-of-the-art bio refinery – one of the UK’s largest facilities solely dedicated to this process. At our bio refinery, it goes through an intensive series of refining, reaction, and separation processes to turn it into high-quality, low-odor green fuel that’s then distributed through our national distribution network.

Biodiesel can be found at garage forecourts across the UK, blended at up to 4.75% with traditional diesel fuel for use in engines. When spilled accidentally or intentionally it quicklydegrades into harmless forms that won’t pollute the environment; its higher flash point means it will not ignite upon an accident or fire incident.

Biodiesel production requires high-grade raw materials such as canola or rapeseed oil that is low in free fatty acids. When purchasing our biodiesel we use only top quality raw materials; to do this we rely on canola or rapeseed oils which contain less free fatty acids. You can easily identify our quality oils by inspecting what arrives in jugs and containers: its color should differ significantly from fresh or unopened cooking oils, may contain small food particles and water droplets but these will be removed easily during refinement processes.

GLT will enable us to use even less expensive raw materials in the long term, as their research work at the Centre for Process Innovation will open up even cheaper sources for biodiesel production from feedstocks with one or two percent contaminants – far superior than current energy-intensive processes which only use refined virgin vegetable oils that have had all contaminants removed prior to refinement. This exciting development opens the door to recycling plastic trash as well as agricultural and household waste in this manner.