Made by adeeba shamim Student of petroleum technology department5/1/2012
ALKYLATION Alkylation is the transfer of alkyl group from one molecule to another Alkyl group may transferred an alkyl carbocation free readical a carbanion or a carbene (or their equipment)Alkylation process used in many aspect of chemistryIn oil refineries: in oil refineries alkylation process refers to a particular alkylation of iso butane with olefins it is a major aspect of up grating of petroleum
NUCLEOPHILIC ALKYLATINGAGENTS Nucleophilic alkylation (carbanion) e.g. include the use of organometallic compound such as Grignard (organo magnesium)agent. organoithm and organosidium reagent .these compound typically can add to an electro deficient carbon atom such as to carbonyl group they are also alkyl ate alkyl and aryl halides as exemplified by suzuki couplings. Where Grignard is the chemical process in which alkyl may halide add to a carbonyl group for sale are in production plant.
ELECTROPHILIC ALKYLATINGPROCESS Electrophilic alkylating agent deliver the equivalent of an alkylation Electrophilic soluble alkylating agent are often very toxic ,due to their ability to alkylate DNA. they should be handled by proper ppe. the mechanism of toxicity is also responsible for the ability of some alkylating agent to perform as anti –cancer drug in the form of alkylating antineoplastic agent.
CARBENE ALKYLATING AGENT Carbene are extremely reactive and are known to attack even un- activated c-h bend carbenes can be generated by elimination of a diazo group Where diazo group is a type of organic compound called diazo compound heat with nitrogen atom
IN OIL REFINERIES USES OFALKYLATION In standard oil refining process ,iso butane is alkylated with low molecular weight. Alkenes (primarily a mixture of propane and butane) in the presence of a strong and catalyst, either sulfuric Acid or hydro fluoric acid.In an oil refinery it is referred as sulfuric acid alkylation unit (SAAU) or hydrofluoric alkylation unit .(HFAU) refinery worker may simply referred it the alkyl unit .
SAAU plant required lower temp so water medium need to be chilled for catalytic processHFAU normal refinery cooling water will suffice“ Since crude oil generally contain only up to 10 to 40% of hydrocarbon refineries use fluid catalytic cracking process to convert high molecular weight hydrocarbon Into smaller and more metallic compound which are then converted in to liquid gasoline size hydrocarbon”.
COMBINING CRACKINGPOLYMERIZATION Combining polymerization ,and alkylation can result in gasoline yield represent 70# of the starting crude oil, more advanced process such as cyclization of paraffins and dehydration of naphthenic forming aromatics hydrocarbon in a catalytic reformer ,have also been developed to increase the action rating of gasoline. Refineries examine whether it makes sense economically to install alkylation units. in addition to a suitable quantity of feed stock the price spread by the value of alkylate product and value must be large enough to justify the installation
HF- ALKYLATION PROCESS Primary process technique1.Alkylation occurs in the presence of a highly acidic catalyst process step2.Olefins from fcc are combined with iso butane and feed to the hf reaction where alkylation occur3.Acid settler separates the free hf from hydrocarbons and recycles the acid back to the reactor.4. A portion of the hf is generation remove acid oil formed by feed contamination of hydrocarbon polymerization.
5. Hydro carbon from settler to the delso- butinizer for fractionating the propane and iso –butane from n- butane and alkylate6. Propane is fractionated from the iso –butane ,propane as a product and iso –butane to be recycled to the reactor7. N-butane and alkylate deflourized in a bed of solid adsorb and fractionated as separate particles ,