The reactor used in a typical hydrotreater unit is more versatile.
In the hydrotreating process, the treated stream is mixed with hydrogen and heated between 500 degree and 800 degree F (260 degree and 427 degree c).
The hydrogen-oil mixture is then charged to a reactor filled with a pelleted catalyst and the following reactions takes place:
- The hydrogen combines with sulphur to form hydrogen sulphide.
- Some of the nitrogen is converted to ammonia.
- Any metals, entrained in oil are deposited on the catalyst.
- Some of the olefins, aromatics and naphthenes become hydrogen
saturated and some cracking takes place, causing the formation of butanes, propane and lighter gases.
- Following figure shows a typical hydrotreater process arrangement.
Catalyst promote a reaction but do not react in any way themselves. The catalyst used inside reactor is generally ball or pallet shaped and depending on the type of service, can be made from variety of materials, including alumina, zinc oxide, or even such an expensive metal as platinum.