N-hexane production process
Most of the foreign hexane production uses molecular sieve adsorption processes, such as Richfielcd (Richfield) and Watson (Watson) in the United States, using reconstituted raffinate as raw material, by recycling two or more beds for adsorption. Press desorption to produce n-hexane.
Most domestic hexane manufacturers use the hydrogenation distillation process, which is divided into two types:
First, hydrogenation then rectification.
Also known as pre-hydrogenation, the raw material is heated by heat exchange, reaches the reaction temperature, enters the hydrogenation reactor, desulfurization and dearomatization reaction under the action of the catalyst, the solvent oil and the hydrogen mixture enter the separation tank for separation, hydrogen recovery, solvent oil into the fractionation tower Cut into finished products. Generally speaking, after the hydrogenation of raw materials, it is still fractionated and cut into n-hexane, and other different types of solvent oil. The advantage is that all raw materials are dearomatized and depleted, making full use of each product. The disadvantage is that the investment is large and the material consumption is high.
Second, rectification then hydrogenation.
Also referred to as post-hydrogenation, in the case of n-hexane, the raw material is first cut into the crude hexane of the 66-69 distillation range, the purity of the crude hexane is greatly improved, and since the phenyl group is contained in n-hexane, the hexane in the crude hexane The content is also greatly increased, and then subjected to hydrodebenzene desulfurization to produce high quality n-hexane. The advantage is that the investment is small and the material consumption is small. The disadvantage is that the unhydrogenated portion is not effectively utilized.