The Geekspeak of Refineries

The biggest key in running complex facilities such as petroleum refineries is communication. Ever wondered how people communicate in such refineries and what technical terms they use? Well here is a list of a few such technical terms you should know about petroleum refineries:


A refinery feedstock is a product or a combination of products derived from crude oil and destined for further processing other than blending in the refining industry. It is transformed into one or more components and/or finished products. It is to keep in mind that feedstock is different from raw materials, those are the ones that are unprocessed.


Off-gases formed at refineries often contain components such as diolefins, olefins, CO2, CO, hydrocarbons, H2S, and various organic sulfur species – all of which are harmful to the environment and subject to increasingly stricter regulations. The goal of the refineries is to minimize the emission of off-gas and further try to convert undesirable products into high-value products


 ADU refers to the Atmospheric Distillation Unit in refineries where lighter hydrocarbons are separated from heavier oils by boiling them off where heavier oils are left in the bottoms which are further passed to a Vacuum Distillation Column also known as VDU, in short, is operated at low pressures or vacuum so that oils in the bottom product can be boiled off without cracking.

Octane and Cetane Number 

Octane no. is the measure of the percentage of isooctane in the fuel when knocking is initiated thereby estimating the performance of the engine. Cetane No. is an indicator of the combustion speed of the diesel fuel. The engine is more effective when Cetane and Octane no. both are high.

Fluid Catalysed Cracking Unit

A process to break long-chain hydrocarbons to small- chain hydrocarbons with heat and catalyst which is a sand-like solid fluidized by hot liquid and vapor. Mostly the products are distillate, gasoline, butane and propane fuels.


Reforming is the process of converting petroleum naphtha obtained from crude oil distillation to high-octane compounds. These compounds, called reformates, generally consist of branched and cyclic alkanes, which have higher octane numbers than straight-chain hydrocarbons. These are further dehydrogenated to form aromatic compounds which have even higher octane numbers.

Since platinum is the most widely used catalyst in reforming, the process is also known as platforming.

A large amount of hydrogen gas is formed as a by-product, which is reused in other refinery processes such as hydrodesulfurization and hydrocracking. 


HDS is the abbreviation for ‘Hydrodesulfurization’, which, as the name suggests is the removal of sulfur using hydrogen gas from refinery products such as gasoline, diesel, fuel oil, naphtha streams, etc. Due to its application in HDS, hydrogen gas is also known as a detergent in refineries. 

Removal of sulfur from refinery products is very crucial for both environmental and commercial reasons. Sulfur is a major pollutant in fuels. In naphtha streams, high amounts of sulfur can poison precious metal catalysts used in reforming processes. H2S gas obtained from HDS is converted to elemental sulphur and sulfuric acid, which constitute the majority of the global supply of sulfur.


O2C stands for ‘Oil to Chemicals’ (also referred to as COTC – Crude Oil to Chemicals) is the latest buzzword in the future of refineries. Traditionally, refineries converted nearly 50-80% of the feedstock into transportation fuels (e.g. gasoline, diesel, etc), but with the integration of O2C technologies, they are gradually shifting the focus of production to high-value chemical products. This holds special significance in light of falling demand for conventional fuels, environmental concerns and a general rise in demand for petrochemicals.

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