Hydrorefining

The most selective and widely used catalyst is palladium, usually on an alumina support. A bimetallic palladium catalyst has also been developed.310 Palladium is more selective and less sensitive to sulfur poisoning than are nickel-based catalysts. Additionally, sulfides can also be employed. 

C3 Hydrorefining. The aim of C3 hydrorefining is to hydrogenate methylacetylene and propadiene present in the cut. Efficient liquid-phase processes were developed by Bayer314-316 (cold hydrogenation process carried out at 10-20°C) and IFP,317 but hydrogenation in the gas phase is also practiced. 

C4 Hydrorefining. The main components of typical C4 raw cuts of steam crackers are butanes (4-6%), butenes (40-65%), and 1,3-butadiene (30-50%). Additionally, they contain vinylacetylene and 1-butyne (up to 5%) and also some methylacetylene and propadiene. Selective hydrogenations are applied to transform vinylacetylene to 1,3-butadiene in the C4 raw cut or the acetylenic cut (which is a fraction recovered by solvent extraction containing 20-40% vinylacetylene), and to hydrogenate residual 1,3-butadiene in butene cuts. Hydrogenating vinylacetylene in these cracked products increases 1,3-butadiene recovery ratio and improves purity necessary for polymerization.308 

Supported palladium and copper catalysts are usually used. A serious problem of this reaction is that palladium forms a complex with vinylacetylene below 100°C. This complex is soluble in the hydrocarbon mixture undergoing hydrorefining and, consequently, palladium is eluted from the catalyst. Operating at temperatures above 100°C or the use of bimetallic palladium catalysts310 solves this problem. 

It was not only gasoline production that was fundamental in the late 30s synthetic rubber was just as important. In 1934 BASF and Bayer had developed Buna-S rubber, which was a copolymer containing styrene. Processes were also developed in the U.S. to produce styrene. 

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Different treatments provide lubricant bases having accentuated isoparaffinic structures these are the bases from hydrorefining, hydrocracking and hydroisomerization (see paragraph 10.3.2.2.c.2). 

Hydrorefining can substitute for extraction processes such as furfural where it integrates perfectly into the conventional process scheme. 

Typical feedstock composition, yields and product properties for a hydrorefining unit (to be continued). 1... 

Figures 10.12 and 10.13 show, respectively, a flow diagram for lubricant oil production by hydrorefining and an integrated lubricating oil production unit using both extraction and hydrorefining.

DHR [Druck-Hydrogenium-Raffination German, meaning hydrorefining] A petroleum refining process developed by BASF in Germany. See DHC. 

Gulf HDS A process for hydrorefining and hydrocracking petroleum residues in order to make fuels and feeds for catalytic cracking. Developed by the Gulf Research Development Company. See also hydrodesulfurization. 

Hydrofinishing The final stage in a number of petroleum hydrorefining processes, commonly used in the manufacture of lubricating oil. 

Hydrorefining A general name for petroleum refining processes using hydrogen gas. See also Hydroprocessing. 

Kombi [Kombinations-Verfahren] A liquid-phase petroleum hydrogenation process which combined hydrogenation with hydrorefining. The catalyst contained molybdenum and tungsten on an aluminosilicate. Developed by BASF. 

Sulfur compounds are most commonly removed or converted to a harmless form by chemical treatment with lye. Doctor solution, copper chloride, or similar treating agents (Speight, 1999). Hydrorefining processes (Speight, 1999) are also often used in place of chemical treatments. When used as a solvent, naphtha is selected for its low sulfur content and the usual treatment processes remove only sulfur compounds. Naphtha, with its small aromatic content, has a slight odor, but the aromatics increase the solvent power of the naphtha and there is no need to remove aromatics unless odor-free naphtha is specified. 

Chromia and molybdena were found to effect dehydrocyclization of alkanes under reaction conditions similar to those of aromatization of cyclohexanes.96 Because of its great practical significance in refining (hydrorefining), chromia- alumina was extensively studied in the dehydrocyclization of alkanes. 

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