Neste Oy

Neste Oil Oyj

Neste Ot

Harri Jarvelin

Petri Lindqvist

Matti Koskinen

Juha Jakkula

Juhani Aittamaa

A process for producing alkyl ethers, by etherification of tertiary Colefins with an alkanol, comprising carrying out the etherification in reactor train system primarily configured for dimerization of isoolefins. In the etherification, the ratio of alkanol-to-olefin is 0.5 to 2, calculated from the amount of tertiary Colefins of the fresh feedstock. The invention makes it possible to change the product of the process from dimer to ether and vice versa merely by adjusting specific flows within the process. The present kind of process is therefore readily adaptable to fluctuating market demands for various gasoline octane-boosters (isooctane or MTBE).

Production of fuel components

The invention concerns a process for preparing a tertiary alkyl ether product. The process comprises reacting the isoolefins of an olefinic hydrocarbon feedstock in a reaction zone (1-3) with an alkanol to form a reaction mixture, which is subjected to distillation in a first distillation zone (4). The bottoms product of the first distillation contains the ether(s), whereas the overhead stream contains unreacted alkanol and a mixture of light hydrocarbons. The overhead stream is subjected to a second distillation in a second distillation zone (15). The overhead product of the second distillation mainly contains the lightest hydrocarbons and a small amount of alkanol, and the bottoms product contains an essentially oxygenate-free hydrocarbon stream which can be used as such for alkylation. In order to increase the conversion of the process, a side drawoff is withdrawn from the second distillation zone (15) and recirculated to the reaction zone (1-3).

Process for preparing alkyl ethers and mixtures thereof

A process for producing tertiary alkyl ethers by reacting an olefinic hydrocarbon feedstock, which contains a mixture of reactive C.sub.4 -C.sub.7 isoolefins, with an alkanol in the presence of a catalyst that will enhance the reaction between the isoolefins and the alkanol. By adjusting the weight ratio of the isobutylene to the reactive C.sub.6 isoolefins of the feed to a value of about 0.2 to 10, it is possible to increase the conversion of reactive C.sub.4 's to over 95%, of reactive C.sub.5 's to over 85% and of reactive C.sub.6 's to over 57%.

Process for preparing a mixture of tertiary alkyl ethers

The present invention concerns a process for preparing tertiary alkyl ethers. The process comprises the steps of contacting in the presence of a catalyst a feedstock containing saturated hydrocarbons and dienes having 4 to 7 carbon atoms with an excess of hydrogen in relation to the amount of dienes in the feed in order selectively to hydrogenate at least a part of the dienes, feeding the treated hydrocarbon feedstock together with at least a part of the unreacted hydrogen to a catalytic distillation reactor system which includes at least one distillation column, reacting the C.sub.4-7 isoolefines of the feedstock with methanol or ethanol in the presence of a catalyst to form tertiary alkyl ethers, subjecting the reaction mixture to distillation in the distillation column, recovering the alkyl ethers and substantially all of the unreacted hydrocarbons with the bottoms product of the distillation, withdrawing an overhead product of the distillation, which mainly contains an azeotrope of saturated C.sub.4 hydrocarbons and the alkanol, and maintaining the pressure of the distillation column at least essentially constant by adjusting the amount of gaseous distillate containing hydrogen in the column. The selective hydrogenation operation of the present invention reduces the amount of dienes contained in the feed to below 0.5% and also causes isomerization of olefins to increase the amounts of reactive olefins.

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Helsinki, Finland

Harri Jarvelin