Hydrotreating and Hydrocracking both primarily use the Fischer-Tropsch process to produce energy-rich chemicals. Hydrotreating is used primarily in chemicals, specifically oils and natural gasoline. Reactor Manufacturers in India mainly use Hydrocracking to produce diesel to make kerosene for aviation fuel. But what are the differences between these processes? Here’s how hydrotreating differs from Hydrocracking, its uses, and why they differ.
What is Hydrotreating?
Hydrotreating is a process that uses heated hydrogen and nitrogen to break down complex hydrocarbons into simpler components. The hydrocarbon feedstock is heated in a hydrotreater reactor, which produces hydrogen gas, carbon dioxide, and water as by-products. The key to Hydrocracking is using hydrotreating catalysts, which are used to speed up the reaction process.
Hydrotreating involves heating the feedstock to the point where it becomes a liquid and then adding hydrogen and steam. The hydrogen reacts with the olefin molecules in the feedstock, breaking down their molecular bonds and producing a mixture of hydrocarbon products.
The reactor is fed from a gas-liquid separator, which collects the petroleum fractions from the crude and separates them into their respective feed streams. The product stream is sent to a vacuum distillation column that extracts more of the lighter hydrocarbons from the mixture. After passing through this column, it is sent to an intermediate drum for further processing before being sent to storage or transported for sale.
What is Hydrocracking?
Hydrocracking is a chemical process that converts heavy oils, such as those in crude oil, into lighter products. By using hydrogen and steam, hydrocrackers can convert heavy oil into products such as gasoline, diesel fuel, and jet fuel. Hydrocrackers are often used in conjunction with hydrotreater reactors to increase the yield of these products.
Differences between Hydrotreating & Hydrocracking
There are many differences between hydrotreating and hydrocracking.
The main differences are:
The key difference is that hydrocracking processes produce a mixture of hydrocarbons, whereas hydrotreating processes produce only alkanes.
Hydrotreating is a process that converts hydrocarbon feedstock into a mixture of carbon monoxide, hydrogen, and other products. Hydrocracking is the reverse of hydrotreating and involves cracking hydrocarbons into hydrogen and aliphatic hydrocarbons.
Hydrotreating converts crude oil or other hydrocarbon feedstock into lighter products such as gasoline or diesel fuel. Hydrocracking is performed on petroleum refinery feedstocks to produce high-octane gasoline and diesel fuels with reduced sulfur content. Refineries often use the two processes to produce gasoline or diesel fuel from crude oil.
Hydrotreating is a process that uses heat and pressure to break carbon-hydrogen bonds in the feedstock. It creates lower molecular weight hydrocarbon molecules. These hydrocarbon molecules can then be used as fuel or chemicals. Hydrocracking is an industrial process that uses hydrogen and carbon monoxide to create higher molecular weight hydrocarbon molecules from hydrocarbons with lower molecular weights. It is done by heating the feedstock at high temperatures and pressures. It breaks down the carbon-hydrogen bonds in the feedstock and creates larger molecules.
Hydrocracking requires higher temperatures (around 700 C) than Hydrotreating (about 300 C). It is because, in Hydrocracking, the cracking process occurs at high temperatures under high pressure. In contrast, Hydrotreating takes place at low temperatures under low pressure.
Hydrotreating is an endothermic reaction requiring heat to complete the reaction. Hydrotreating is performed in a hydrogen-containing environment at elevated temperatures. Hydrocracking differs from Hydrotreating in that it occurs in an exothermic environment at lower temperatures than Hydrotreating. Hydrocracking uses catalysts to break down hydrocarbon molecules into smaller hydrocarbons. It can be further processed into other valuable chemicals or fuels.
The differences between both written above are based on operating temperature and pressure. There are other differences in the products produced from each process. Hydrodesulfurization (HDS), used extensively in diesel fuel production, can be produced only by Hydrocracking. It cannot be produced by Hydrotreating alone, because it requires high sulfur content.
As you can see, there are some differences between Hydrotreating and Hydrocracking. However, both processes produce valuable products from complex molecules in petroleum crude oil or natural gas streams.
These differences can have a very important impact on your process design. The key is understanding the fundamental differences in these two types of processes and how those differences can affect your design. The requirements for refinery feedstock or specialty products are big or small, complex or simple. Consider the advantages and disadvantages of both before deciding which of these technologies or both would work best for your next project.
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