User:ZacMH27/sandbox/Shukhov Cracking Process

The Shukhov Cracking Process is a thermal cracking process used to refine crude oil. The process was invented in 1891 by the Russian Engineers Vladmir Shukhov and Sergei Gavrilov. This invention impacted petroleum refining as it allowed for the valuable material such as gasoline found in crude oil to be easily extracted. During the Shukhov Cracking Process, large molecular compounds found in the crude oil are put under high temperature and pressure causing the compounds to break down into smaller and desired substances such as gasoline. The process is still in use today with some modifications made throughout the past century.

The Inventor
Vladmir Grigoryevich Shukhov(28 August 1853 - 2 February 1939) was an engineer for the Tsarist and Soviet Russia. Shukhov is most well known for his contributions to architecture and the oil industry. Shukhov impacted the petroleum industry with the invention of the Shukhov Cracking Process, the first of its kind that allowed the valuable material found in oil to be easily extracted, as well as designing oil pumps to extract oil from underground. Shukhov took a role in the government when the Soviet Union rose to power in Russia, many engineering projects in the 1920s in Russia were associated with him. His accomplishments under the Soviet Union won him the Lenin Prize in 1929 and the title of Hero of Labor in 1932.

The Cracking Process
The cracking process Vladmir Shukhov invented is part of the branch of oil refining known as the thermal cracking process. There are a multitude of different versions of the thermal cracking process with each one having different steps and different products from the reactions that occur. The version that Shukhov invented with his cracking process is referred to as delayed coking.

In delayed coking, crude oil is put under great heat and pressure in order to form products such as LPG, Ethane, Propane, Gasoline, Light and Heavy Gasoil. A byproduct of the cracking process is known as coke, which consists of all the elements in the oil that must be eliminated in order to form the product, including carbon, metals and sulfur. In the process, oil is put under temperatures of 482 degrees Celsius at a pressure of 150 psia(pounds per square inch absolute, 14 psia is the average pressure at sea level ).

The Steps to the Process

 * 1) Vacuum Residue, oil that has been put at pressures less than atmospheric pressure(known as Feed) is heated and pumped into the Fractionator at temperatures of 360 to 400 degrees Celsius.
 * 2) While the feed is at the bottom of the Fractionator it is combined with coking product vapors.  These coking product vapors are gaseous coke that are being recycled from the coke drums, these vapors help to heat the feed.
 * 3) The feed is then moved to the furnace in which temperature ranges from 480 to 500 degrees Celsius.  Cracking reactions begin at around 427 degrees Celsius.  The intense heat from the furnace causes the bonds between structures in the feed to break down into smaller compounds that are gases that will be collected to form fuel products such as gasoline.
 * 4) To maximize productivity, there are 2 coke drums, one is undergoing cracking while the other is being cleaned of the coke. The feed undergoing cracking proceeds to the coke drum in operation where the cracking continues.  Cracked products leave the coke drum as coking product vapor and proceed to the Overhead Vapor Lines, coke formed from the cracking deposits at the bottom of the coke drum and stacks overtime till the drum is filled with coke and must be decoked.
 * 5) The product vapor formed from the cracking process exits the Overhead Vapor Lines and enters into the Fractionator.  Some vapor combines with the incoming feed to go through the process again while other vapor is collected and goes through processes to result in the intended fuel to be formed.

The Removal of the Coke
The coking and decoking cycle typically takes 10 to 24 hours. The decoking process cleans out the coke in the coke drum that forms as a result of the cracking. Here is a sample of the typical processes and time lengths for decoking a coke drum over a 16 hour cycle period: Once a coke drum is filled with coke, feed is directed into the other coke drum and the decoking process begins. The coke is steam stripped(a superheated steam) which disposes of volatile material found in the coke. This is followed by several cycles of pouring water and steam into the drum to clean out the remaining coke and decrease the temperature inside the drum. The drum is then a Hydrostatic test, this test determines the strength of the coke drum and if there are any leaks. If the drum passes the hydrostatically test, the drum is reheated to prepare for the next cycle of feed that requires high temperature for the process to be complete.

Innovations to the Shukhov Cracking Process
Most innovations made to the Shukhov Cracking Process have been made in order to reduce the amount of time and effort required to remove the coke that forms after the completion of the refining process. These changes were able to be implemented as technology and understanding of cracking improved over the past century.


 * When Shukhov first invented the process in 1891 the oil was heated to 371-398 degrees Celsius at a pressure of 90 psia. In 1919, the Dubbs process was invented, which changed the temperature and pressure to 482 degrees Celsius at a pressure of 150 psia.
 * In 2001, Delta Valve began installing Coke Drum Unheading Valves at refineries, which removed the coke from the Coke Drums, known as Unheading, in an automated system.  Prior, unheading was performed manually and was a dangerous process as people would be exposed to hot steam, water, and coke which lead to injuries and death.  The Unheading values increased safety and reduced the time it took to clean the drums.

Impacts
The Shukhov Cracking Process is commonly cited as being the first thermal cracking process to be invented and is also the most commonly practiced technique for refining oil.

Growth in Use of the Shukhov Cracking Process
Initially the Shukhov Cracking Process had little use in the petroleum industry as there was little demand at the time for a light gasoline at the time. However with the inception and growth of the automotive industry in the early 1900s there became a demand for large quantities of light gasoline that the Shukhov Cracking Process could achieve. The automotive industry led a gradual increase in thermal cracking refineries around the United States and the world. With the economic boom that followed World War 2 cars became more affordable, which led to exponential use of the Shukhov Cracking Process. In 1998 there were 49 delayed coker refineries in the United States. By 2014, the capacity of barrels of oil of output that could be produced per day in the United States by the Shukhov Cracking Process was 3 million, an increase of nearly 26% from the previous decade.

Environmental Impacts
There are a multitude of environmental issues that have emerged from the use of the Shukhov Cracking Process.


 * The Shukhov Cracking Process has enabled the continued use of oil, a fossil fuel which admits greenhouse gases which cause global warming.
 * Refineries tend to use fresh water in their production processes. With fresh water scarcity being relevant, the petroleum industry has played a factor in the scarcity.
 * The decoking process releases VOC(volatile organic compounds) which lead to the production of ozone, a greenhouse gas.