Critical Infrastructure – How Refineries Work 

April 8, 2020

The U.S. Department of Homeland Security website says “there are 16 critical infrastructure sectors whose assets, systems, and networks, whether physical or virtual, are considered so vital to the United States that their incapacitation or destruction would have a debilitating effect on security, national economic security, national public health or safety, or any combination thereof.1”   

Of these 16 sectors designated as essential, the energy sector is considered uniquely critical because it facilitates most, if not all, of the other sectors functionality1

The energy sector is divided into three segments: electricity, oil, and natural gas.  In this sector, refineries are extremely important assets as they convert crude energy, such as oil, into usable products that fuel other essential sectors and aspects of our everyday life3.  

Let’s explore the process refineries use to convert raw materials into functional energy sources, as explained by the American Fuel & Petrochemical Manufacturers (AFPM) website. 

#1: Start with crude oil 

Refineries first obtain crude oil, or unrefined liquid petroleum, which according to National Geographic is “formed from the remains of ancient marine organisms, such as plants, algae, and bacteria”2,4. Through oxygen deprivation, these organisms became a waxy substance called Kerogen, which went through a process called catagenesis in which heat and pressure were administered over long periods of time to the Kerogen to become hydrocarbons4. Through different combinations of heat and pressure with the addition of time, different hydrocarbons are formed, the most common of which we call “coal, peat, and natural gas”4. Through different scientific processes these natural energy sources are transformed into usable energy and supplied via man-made infrastructure such as pipelines, refineries, and transportation systems. 

National Geographic indicates that the majority of global refineries “focus on producing transportation fuels” with U.S. refineries producing “about 19 to 20 gallons of motor gasoline, 11 to 12 gallons of distillate fuel, and 4 gallons of jet fuel” on average, from a 42-gallon barrel of crude oil”4

#2: Turn crude oil into usable fuel 

To turn the aforementioned crude oil into usable fuel, refineries pipe the oil through heated pipes set to different temperatures to separate the liquid into vapor. The crud material is piped into a structure called a distillation unit. Vapor rises to the top of the unit and turns back to liquid once cooled2,4. According to the AFPM, "the liquids are then drawn off the distilling column at specific heights to obtain fuels like gasoline, jet fuel and diesel fuel.2” 

#3: The liquids are processed further 

Once the liquids are collected in the distilling column, some liquids depending on what they are and what they are meant for, undergo additional processes to create usable fuel.  

The AFPM describes these processes as:  

  • cracking, which is breaking down large molecules of heavy oils; 

  • reforming, which is changing molecular structures of low-quality gasoline molecules; and 

  • isomerization, which is rearranging the atoms in a molecule so that the product has the same chemical formula but has a different structure2.  

Through these processes multiple types of fuels are created as well as “plastics and leading-edge technological devices like artificial heart valves”2.   

The equipment necessary to refine crude oil into the essential fuels and other products used in everyday life, are controlled with Operational Technology (OT). OT is the hardware and software that detects or causes a change, through the direct monitoring and/or control of industrial equipment such as its valves, pumps, etc.  

OT and the energy industry are essential to the functioning of the U.S. Apply for one of Capitol Technology University’s degrees in Critical Infrastructure to gain experience in IT, OT, and Cybersecurity learn about their applications in the 16 critical infrastructure sectors. 


  1. Cybersecurity & Infrastructure Security Agency. Energy Sector. Retrieved from

  2. Fuel & Petrochemical Manufacturers. (2020). How Refineries Work. Retrieved from

  3. U.S. Energy Information Administration. (2019, May 23). Oil: crude and petroleum products explained. Retrieved from

  4. National Geographic. (2020). Petroleum. Retrieved from