257results about "Fractional condensation purification/separation" patented technology

The invention relates to a separation method for non-cryogenic low-carbon hydrocarbon containing light gases. The method comprise the steps as follows: (1) pre-treated gas at the outlet of a reactor is cooled to the temperature of 10-37 DEG C and sent to a pre-cutting tower; (2) a product at the top of the pre-cutting tower is cooled and sent to an absorption tower, and C2 hydrocarbons in the product at the top of the pre-cutting tower are absorbed by an absorbent consisting of C3, C4, C5 or the mixture of hydrocarbons thereof; and (3) tower kettle products of the pre-cutting tower are sent to a deethanizing column for clearly cutting the C2 and the C3 to obtain C2 distillate at the top of the tower; the tower kettle products are C3 and heavier components. Compared with the prior art, the method has the advantages of lower investment, lower energy consumption, higher recycling rate of materials, simpler operation, less maintenance workload, reliable operation, etc.

An ethylbenzene production system comprises a reactor vessel, a vapor phase ethylene feed stream, a benzene feed stream entering the reactor vessel, and a product stream containing ethylbenzene exiting the reactor vessel. The reactor vessel has an ethylation section and a benzene stripping section, whereby fluid communication via integrated vapor and liquid traffic is maintained between the ethylation section and stripping section. The vapor phase ethylene feed stream contains 3 to 50 mol % ethylene and at least 20 mol % methane entering the reactor vessel.

Recycle of a stream comprising C₈ oligomers to an oligomerization zone to be oligomerized with C₄ olefins can produce diesel range oligomers. A diesel stream can be separated from a gasoline stream which can be recycled to the oligomerization zone.

Processes utilizing the integration of (i) processes and the associated equipment used to purify and recover propylene from propane- and/or C₄+-containing refinery hydrocarbon streams, with (ii) catalytic dehydrogenation are disclosed. This integration allows for elimination of some or all of the conventional fractionation section of the dehydrogenation process, normally used to purify propylene from unconverted propane in the reactor effluent. Significant capital and utility savings are therefore attained.

A method is disclosed a method for recovering olefins and for producing hydrogen from a refinery off-gas stream in which such stream is conventionally pretreated and separated to obtain a light ends stream that contains nitrogen, hydrogen and carbon monoxide and a heavy ends stream that contains the olefins. The light ends stream is subjected to reforming and a water gas shift reactions after addition of a natural gas stream. The addition of the natural gas increases the hydrogen recovery from the light ends and also stabilizes the hydrocarbon content in the stream to be subjected to the reforming and water gas shift reactions. The heavy ends can be further treated to recover olefins such as ethylene and propylene. The rate of natural gas addition is controlled so that the concentration of the nitrogen in a stream exiting the water gas shift reactor is less than about 5 percent by volume so that hydrogen separation from such stream becomes practical.

A process for ethane extraction from a gas stream based on turboexpansion and fractionation with no mechanical refrigeration is provided. The feed gas is sweetened and dehydrated by a conventional amine process and by a molecular sieve unit, to remove carbon dioxide and water. After this pretreatment, the feed gas undergoes to a series of cooling steps through a cryogenic brazed aluminum heat exchanger and fed to a demethanizer column. A stream rich in methane is recovered from the top of this column and fed to a centrifugal compressor and subsequently routed to a booster/turboexpander. The temperature of the methane gas is greatly reduced by the expansion allowing the cooled methane stream to be a cooling source for cryogenic heat exchanger. Feed for a de-ethanizer column comes from the bottom liquids of the de-methanizer column. Ethane is recovered overhead at the de-ethanizer column.

Methods and systems are provided for converting methane in a feed stream to acetylene. The hydrocarbon stream is introduced into a supersonic reactor and pyrolyzed to convert at least a portion of the methane to acetylene. The reactor effluent stream may be treated to convert acetylene to another hydrocarbon process. The method according to certain aspects includes controlling the level of water, carbon dioxide and other condensable contaminants in the hydrocarbon stream by use of a fluid separation assembly such as a supersonic inertia separator. In addition, one or more adsorbent beds may be used to remove remaining trace amounts of condensable contaminants. The fluid separation assembly has a cyclonic fluid separator with a tubular throat portion arranged between a converging fluid inlet section and a diverging fluid outlet section and a swirl creating device.

The invention discloses a method for reclaiming ethylene in catalytic dry gas, belongs to an ethylene separation method, and provides the method for separating the ethylene from the catalytic dry gas by using mixed gas as refrigerant in order to solve the problems that the prior process for reclaiming the ethylene from the dry gas of a refinery has high energy consumption, large equipment scale, high investment and the like. The method adopts an expander and an ice chest to reclaim cold energy through three-stage compression and refrigeration, and then obtains material flow rich in the ethylene from a tower bottom by removing methane and hydrogen in a methane removing tower so as to greatly improve the reclamation rate of the ethylene and reduce the energy consumption. The method of the invention has the advantages of less equipment, simple flow, simple refrigeration cycle and less investment.

The invention relates to a high and low-temperature Fischer-Tropsch synthesis co-production technology which is characterized in that the high-temperature Fischer-Tropsch synthesis technology and the low-temperature Fischer-Tropsch synthesis technology are coupled; a coal gasifying and purifying unit is adopted to produce synthetic gases; the purified synthetic gases (CO+H2) enter a high-temperature Fischer-Tropsch synthesis unit and a low-temperature Fischer-Tropsch synthesis unit at different ratios of CO to H2 respectively; and the crude products obtained by the high-temperature Fischer-Tropsch synthesis unit and the low-temperature Fischer-Tropsch synthesis unit form a mixture flow which enters the subsequent oils deep-processing unit and hydrocarbon gas downstream processing unit according to the characteristics of different crude products to produce gasoline, diesel oil, synthetic lubricating oil, polypropylene, polyethylene and high value-added alpha-olefin. The technology provided by the invention avoids the uncertainty of the oils market under the fluctuation of the international crude oil market, realizes balance of the oils income by use of the income of chemical products, and finally achieves the aim of enhancing the competitiveness of the Fischer-Tropsch synthesis oils.

The invention discloses a membrane separation process for recovering organic hydrocarbons and nitrogen from the tail gas of a polyethylene device. The recovery technology caustic-washes, compresses and cools the tail gas; the tail gas after being cooled is put in a segregator, and the organic hydrocarbons is separated and recovered; gas exhausted from the segregator is put in an organic steam membrane; the gas which enters into a membrane separator is divided into a permeating airflow rich in the organic hydrocarbons and a retentate airflow rich in N2. The technology can lead the recovery rate of the organic hydrocarbons to reach more than 99 percent, lead the recovery rate of the nitrogen to reach more than 99 percent, and lead the purity to be 99 percent. The membrane separation process is applied to the recovery and treatment of the tail gas of the polyethylene device.

The invention discloses a recycling device of p-xylene and methyl acetate, which comprises the following parts: high-effective condenser, which quenches gas p-xylene and methyl acetate into liquid; oil-water separator, which separates p-xylene and methyl acetate from water automatically. The invention solves the problem of tail gas with liquid as well as the problem of separation and recycling.

A process for recovering unreacted olefin in a polyolefin manufacturing process comprising the treatment of a purge bin vent gas. The process involves cooling and condensing the vent gas (purge stream), which contains at least an olefin, a paraffin, and nitrogen, to produce a liquid condensate and an uncondensed (residual) gas stream. Both streams are then passed through membrane separation steps. The membrane separation of the uncondensed gas stream results in a residue stream containing mostly nitrogen and/or paraffin and a permeate stream enriched in either C₂₊ hydrocarbons or olefin, depending on the type of separation. The permeate from this step is recirculated within the process prior to the condensation step. The membrane separation of the condensate results in a residue stream containing paraffin and a permeate stream enriched in olefin, which may be recycled to the polymerization reactor.

The present invention concerns a process for recovering lower carbon olefins from MTO or DTO product gas. Said process primarily comprises the product gas compressing, pre-deethanizing, demethanizing and ethylene recovering apparatus, depropanizing column, ethylene rectification column, propylene rectification column and the like. In addition, the process of the present invention needs no independent ethylene cooling system, and the ethylene recovery rate may achieve 99.5%.

A process for producing olefins from a coal feed includes providing a coal tar stream and fractionating the coal tar stream to provide a hydrocarbon stream that includes hydrocarbons having an initial boiling point of about 250° C. or greater. The hydrocarbon stream is hydrotreated to reduce a concentration of one or more of nitrogen, sulfur, and oxygen in the hydrocarbon stream, and the hydrotreated hydrocarbon stream is cracked in a fluidized catalytic cracking zone to produce an olefin stream.

A process for recovering unreacted olefin in a polyolefin manufacturing process comprising the treatment of a purge bin vent gas. The process involves cooling and condensing the vent gas (purge stream), which contains at least an olefin, a paraffin, and hydrogen, to produce a liquid condensate and an uncondensed (residual) gas stream. Both streams are then passed through membrane separation steps. The membrane separation of the uncondensed gas stream results in a residue stream containing mostly nitrogen and/or paraffin and a permeate stream enriched in either C₂₊ hydrocarbons or olefin, depending on the type of separation. The permeate from this step is recirculated within the process prior to the condensation step. The membrane separation of the condensate results in a residue stream containing paraffin and a permeate stream enriched in olefin, which may be recycled to the polymerization reactor.

A method is described for processing an olefin-containing product stream (1) that contains, besides ethylene and propylene, longer-chain olefins and compounds of hydrocarbons with oxygen (oxygenates). Such a product stream (I) can occur in particular in olefin synthesis from methanol. The product stream is dewatered in successive process steps, optionally compressed in several steps and dried. Then it is subjected to fractionation. For removal of the undesired oxygenates it is proposed that the oxygenates be washed out of the gaseous product stream after the compression steps and before the drying step in a column (12) with methanol.

A process for treating an effluent gas stream arising from a manufacturing operation that produces an olefin or a non-polymeric olefin derivative. The process involves cooling and condensing the effluent gas stream, which comprises an olefin, a paraffin, and a third gas, to produce a liquid condensate and an uncondensed (residual) gas stream. Both streams are then passed through membrane separation steps. The membrane separation of the uncondensed gas stream results in an olefin-enriched stream and an olefin-depleted stream. The olefin-enriched stream is recirculated within the process prior to the condensation step. The membrane separation of the condensate also results in an olefin-enriched stream, which may be recycled for use within the manufacturing operation, and an olefin-depleted stream, which may be purged from the process.

The invention belongs to the field of chemical engineering, and particularly discloses a method and a device for separating ethylene from refinery plant dry gas. The method comprises the steps of compression, purification, cooling, absorption, propane removal, methane removal, and ethylene refining. The method is based on a shallow cold oil absorption technology, directly produces a polymer-gradeethylene product from refinery plant dry gas on the premise that the refrigeration process is simplified, the cold consumption is reduced and the investment is saved, and has great industrial application prospects.