Uop Lcc

Union Carbide Corporation

Carmen M Yon

Henry Rastelli

Stanley Joseph Frey

John Markovs

Joe Quock

Gordon T Cartwright

Wim P Reel

John Patrick Brady

A process is provided for the removal of trace amounts of aromatic hydrocarbons from an acid waste gas feed stream comprising sulfur compounds and the aromatic hydrocarbons. An adsorption process employing an adsorbent such as a high silica zeolite adsorbent having a framework silica-to-alumina ratio greater than about 15 and having a pore size greater than about 6.2 angstroms is used to remove from the feed gas mixture aromatic hydrocarbon contaminants and permit the recovery of a high purity sulfur product from the treated effluent stream. The use of the present invention removes aromatic hydrocarbon contaminants which are responsible for the degeneration of the performance of the downstream sulfur recovery zone.

Sulfur production process

A process is provided for the removal of trace amount of aromatic hydrocarbons from a waste feed gas stream comprising sulfur compounds and the aromatic hydrocarbons. An adsorption process employing an adsorbent such as a high silica zeolite adsorbent having a framework silica to alumina ratio greater than about 15 and having a pore size greater than about 6.2 Angstroms is used to remove from the feed gas mixture aromatic hydrocarbon contaminants and permit the recovery of a high purity sulfur product from the treated effluent stream. The adsorption zone comprises at least 2 adsorption beds wherein one of the first adsorption beds is operating in an adsorption mode and the other is being regenerated at a desorption pressure higher than the adsorption pressure. The regeneration is performed in a closed system or partially closed system, and prior to returning a regenerated adsorption zone to adsorption conditions the waste feed gas stream is used to cool and purge the regenerated zone. Purge effluent from the regeneration zone is passed to a bed undergoing adsorption in a lead/trim configuration to prevent a slug of aromatic hydrocarbons from entering the adsorption effluent. The use of the present invention removes aromatic hydrocarbon contaminants which are responsible for the degeneration of the performance of the downstream sulfur recovery zone.

The present invention relates to a cyclic process for the preparation of ethyl tert.-alkyl ethers by the reaction of an alcohol, such as ethanol, with an iso-olefin such as isobutylene or isoamylene wherein an effluent from the reaction zone is first separated in a distillation column to provide an overhead effluent stream and a bottoms effluent stream comprising ethyl tert.-alkyl ether and unreacted ethanol, and the ether product is passed to an adsorption zone to remove the unreacted ethanol. When the reaction occurs in the presence of water, a tert. alcohol (e.g., TBA or TAA) is produced and, if returned to the reaction zone, the tertiary alcohol builds up in the process and reduces efficiency. An adsorbent selected from the group consisting of zeolite 13X, silica-bonded silicalite, an alkali-exchanged zeolite with an MFI structure having a silica/alumina ratio greater than 20 and mixtures thereof is employed in an adsorption zone to remove the unreacted ethanol from the ether product to provide ether product essentially free of ethanol and comprising the tertiary alcohol. Thus, the tertiary alcohol is removed with the ether product as a high octane, oxygenate blending component for reformulated gasoline with a low vapor pressure. The invention is useful in recovering unreacted ethanol from the other product stream and returning the unreacted ethanol to the reaction zone without returning TBA. The invention prevents the build-up of tertiary alcohol in the unreacted ethanol stream which adversely affects the operation of the reaction zone and reduces catalyst stability.

Process for the production of ethyl tert.-alkyl ethers

The present invention is a cyclic process for the preparation of ethyl tert.-alkyl ethers by the reaction of an alcohol, ethanol, with an iso-olefin such as isobutylene or isoamylene wherein an effluent from the reaction zone is separated in a distillation column to provide an overhead effluent stream and a bottoms effluent stream comprising ethyl tert.-alkyl ether and unreacted ethanol. The unreacted ethanol is recovered in an adsorption zone comprising a selective adsorbent selected from the group consisting of zeolite 13X, sodium zeolite Y, alumina, silicalite and mixtures thereof. The invention is useful in recovering unreacted ethanol from the bottoms effluent stream and returning the unreacted ethanol to the reaction zone. The invention reduces the cost of this separation which is complicated by the formation of an azeotrope between the unreacted alcohol and the ether.

A process is provided for the removal of heavy hydrocarbons from a feed gas mixture. An adsorption process employing a high silica zeolite adsorbent having a silica to alumina ratio greater than about 20 and having a pore size greater than about 4.5 Angstroms is used to remove from the feed gas mixture heavy hydrocarbon contaminants and permit the further treatment of the feed gas for the bulk removal of carbon dioxide. The adsorption zone comprises at least 2 adsorption beds wherein one of the first adsorption beds is operating in an adsorption mode and the other is being regenerated. The effluent from the adsorption zone, depleted in heavy hydrocarbons is passed to a membrane treating zone to provide a non-permeate stream depleted in carbon dioxide. At least a portion of the non-permeate stream is heated and the heated non-permeate stream is used to regenerate the adsorption zone. The use of the present invention removes heavy hydrocarbon contaminants which are responsible for the degeneration of the performance of the membrane treating zone.

Process for rejecting heavy hydrocarbons from light hydrocarbons gases

The present invention relates to a process for the separation of ethanol from a mixture thereof with ethyl tert.-alkyl ether employing a selective adsorbent comprising a mixture of sodium zeolite Y in combination with alumina wherein the percentage of the sodium zeolite Y ranges between 10 and 40 wt-%. The invention reduces the cost of this separation which is complicated by an azeotrope formation between the alcohol and the ether.

Adsorbent for the separation of ethanol from ethyl tert.-alkyl ether

A process for the regeneration of oxygenate containing adsorbents uses regenerant streams such as LPG and isomerate products for the desorption of oxygenate compounds. The process discloses arrangements for the integration of regenerant treatment into the adsorption scheme and for the enhancement of the isomerate product. The integrated flowscheme can be used to remove sulfur and water from contaminated regenerants or to deliver the oxygenates into the gasoline pool.

Liquid phase adsorption process

A process for the etherification and separation of C.sub.3 -C.sub.5 hydrocarbons is improved by the advantageous integration of an oxygenate recovery unit having a 3-bed arrangement into the etherification separation section. A feedstream including C.sub.3 hydrocarbons and isobutene are reacted with methanol in an etherification to produce an etherification effluent that is separated in a first separator into a bottoms stream of MTBE product and an overhead stream of unreacted isobutane, methanol, other oxygenate compounds and C.sub.3 -hydrocarbons. After recovery of methanol, in an adsorptive separation process, the methanol deficient overhead stream enters a second separation zone in the form of depropanizer for the separation of isobutane and higher boiling hydrocarbons from the C.sub.3 hydrocarbons. Any oxygenate compounds that are carried from the bottom of the column with the C.sub.4 + hydrocarbon stream are removed in an oxygenate recovery unit designed to produce an ultra pure product essentially free of oxygenates. A portion of the purified hydrocarbons from the oxygenate recovery unit are recycled as regenerant through the oxygenate recovery unit to desorb oxygenate compounds. This integration of the oxygenate recovery unit provides a closed loop for its regeneration that utilizes existing separation facilities for the removal of oxygenate compounds from the hydrocarbons of the regenerant stream.

Liquid adsorption process to produce an ultra pure product

In a fixed-bed vapor phase adsorption cycle for bulk separations wherein the heat front generated by the exothermic heat of adsorption is maintained in the bed either in or behind the mass transfer zone, and is subsequently utilized in the purge desorption/regeneration of the bed, improved efficiency and enhanced versatility with respect to the degree of product purity is obtained by treating the regeneration purge gas with a portion of the purified product.

Growing community of inventors

Carmel, NY, United States of America

Carmen M Yon