Refineries and petrochemical plants are like steel cities that never sleep, turning crude oil into a wide range of fuels, gases and chemical products for industry, not to mention plastics for all uses. Shown here is the Ras Laffan refinery in Qatar.
1. Refining and Petrochemicals in 15 images
1. Refining and Petrochemicals in 15 images
2. Separation by atmospheric distillation
The first step in the refining process is to separate the hydrocarbon molecules according to weight. The crude oil is heated to 400°C in a 60-meter-high distillation column. The products are separated from lightest to heaviest, with bitumen falling to the bottom and gases rising to the top. Pictured here is Total's Donges refinery in western France.
3. Conversion by catalytic cracking
After distillation, the proportion of heavy hydrocarbons in the mix is still too large. These heavy molecules are broken down or 'cracked' by raising the temperature to 500°C in the presence of a catalyst. Catalytic cracking converts 75% of the heavy products into gas, gasoline and diesel. This picture shows the cracking unit at the Donges refinery.
4. High-precision processes
Conversion operations can be improved by adding hydrogen (hydrocracking) or extracting carbon. The more complex the operation, the more it costs and the more energy it uses. All operations must be closely monitored. Shown here is the hydrocracking pilot unit at the Total research center in Normandy, France.
5. Enhanced environmental performance
Some procedures eliminate or significantly reduce molecules that are corrosive or cause air pollution. This is particularly true for sulfur, which is subject to strict standards within the European Union. Diesel desulfurization takes place at 370°C and a pressure of 60 bar. This picture shows the sulfur recovery unit at the Donges refinery.
6. The link between refining and petrochemicals
Petrochemical units recover refining distillates such as naphtha and use them as feedstock for other products, like plastics. Refineries and petrochemical units are often located on the same site for greater energy efficiency. This picture shows Total's Gonfreville-l’Orcher petrochemical plant, as seen from the Normandy refinery.
Naphtha can be converted into intermediate products known as aromatics, such as benzene, toluene and xylene, in a distillation column at temperatures above 500°C. These aromatics are then used as solvents in the chemical industry. Here, an engineer is shown carrying out an inspection on top of the distillation column at the Hanwha Total Petrochemical plant in South Korea.
8. Olefins or alkenes
The long chain molecules in naphtha are cracked into smaller chains using high temperatures and steam. This process, known as 'steam cracking' is used to obtain olefins (or alkenes) such as ethylene, propylene, butane and butadiene. After polymerization, these molecules form the basis of many plastic materials. Shown here is the ethylene unit at the Hanwha Total Petrochemical in South Korea.
9. Sea links
Refineries and petrochemical plants are often located along rivers near deepwater ports or give directly onto the sea to make transporting products easier. Here the Hanwha Total Petrochemical plant in South Korea is shown with its offshore loading dock.
10. Major accident hazards
Refineries and petrochemical plants are governed by strict safety measures. Staff also undergo regular safety training, like this fire drill at the Port Arthur refinery's sulfur processing unit in Texas.
11. Plastics manufacturing
Ethylene and propylene can group into huge molecules forming long chains. They are often first sold in pellet form and melted, extruded or molded into objects made out of a variety of materials, including polyethylene, polypropylene and polystyrene.
Polyethylene is the most common plastic in the world and is widely used in packaging for plastic shopping bags, bottles and films. In its more solid form, popular uses include toys and pipes. Seen here is the Carling-Saint-Avold plant in eastern France.
Polystyrene foams are widely used for insulation. Polystyrene is also used to manufacture televisions, household appliances and food packaging. This picture shows the polystyrene storage area at the Carling Saint-Avold plant.
Polypropylene is known for being extremely tough and resilient. This makes it a popular choice in the automotive industry for car bumpers and dashboards. Here, a unit used for the initial polypropylene processing phase is shown at the Samsung Total Petrochemicals in Guangzhou, Guangdong Province (China).
15. Plastics in automotive innovation
Modern vehicles contain an increasing number of thermoplastic parts. This allows for a more flexible design and, more importantly, reduces vehicle weight, cutting fuel and electricity consumption as well as CO2 emissions. The Daimler-Benz smart car shown here was designed as a light, compact urban vehicle.