The Burton process is a method of thermal cracking that involves breaking down complex organic molecules into simpler molecules, specifically gasoline, diesel, and other related fuels. This is accomplished by exposing crude oil to temperatures in excess of 1,472°F (800°C) and pressures of around 100 PSI (700 kilopascals). Under those conditions, the crude oil molecules are cracked into gasoline molecules and other valuable substances. This method was patented in the year 1913, and was instrumental in doubling gasoline production in that year. The Burton process was later replaced by catalytic cracking in most applications, though it remains an important method for the manufacture of fuel oils such as petrodiesel.
During the early days of oil refining, the most common method used to produce usable fuel from crude oil was fractional distillation at regular atmospheric pressure. This method was both costly and inefficient, and proved incapable of keeping pace with the growing demand for gasoline. Around the turn of the 20th century, a handful of chemists were tasked with developing a better method for refining crude oil. This led to the invention of the Shukhov cracking method in Russia during the early 1890s, and the Burton process in the United States in the year 1913. These thermal cracking methods were responsible for a significant increase in the percentage of gasoline obtained from each barrel of crude oil.
Thermal cracking is a process that can be used to reduce complex molecules into simpler components. That general principal is at the heart of the Burton process, which effectively breaks down crude oil molecules into useful gasoline and diesel molecules through thermal cracking. In order to accomplish this, the crude oil is first fed into a pressure vessel. The oil is then heated, and the pressure inside the still is simultaneously increased. In order to successfully crack crude oil molecules, the minimum required pressure is about 75 PSI (517 kPA), and the temperature must be at least 850°F (about 450°C), though much higher pressures and temperatures can be used.
Between the years of 1913 and 1937, the Burton process was the the primary method of producing gasoline. After 1937, it was largely superseded by the more efficient catalytic cracking method. Fluid catalytic cracking results in a larger percentage of gasoline by volume than the Burton process, and also results in more valuable byproducts. The Burton process is still useful in the refining of fuel oil though, which is produced at different temperatures and pressures than gasoline.