Abstract:
A process for separating acrylonitrile from a mixture of acrylonitrile and acetonitrile includes providing a mixture of acrylonitrile and acetonitrile to a recovery column; contacting the mixture of acrylonitrile and acetonitrile with aqueous solvent to provide an acrylonitrile-water azeotrope; and separating the acrylonitrile-water azeotrope from the acetonitrile to provide an overhead stream that includes the acrylonitrile-water azeotrope and about 0.05 weight percent or less acetonitrile, a bottoms stream that includes about 0 to about 0.0075 weight percent acetonitrile, and a sidestream that includes about 5 to about 70 weight % acetonitrile.
Abstract:
A process and system for removing heavy organic impurities from a process stream includes providing a process stream having water and about 0.5 to about 1.5 weight percent heavy organic impurities. The process includes separating water from the heavy organic impurities in an evaporator system having one or more evaporation stages to provide an aqueous condensate and a liquid residue. The aqueous condensate has about 0.1 weight percent or less heavy organic impurities and the liquid residue has about 3 to about 10 weight percent heavy organic impurities.
Abstract:
A method is provided comprising adding acid to a reflux stream, and conveying the reflux stream to an acetonitrile fractionator, wherein the acid reduces fouling in the acetonitrile fractionator.
Abstract:
The cooling coils used in a commercial oxidation or ammoxidation reactors can be made more closely packed by providing the individual courses defining the cooling coil in a transverse arrangement rather than a linear alignment.
Abstract:
An apparatus comprises a heads column and an overhead system. The heads column is configured to receive a crude nitriles feed stream. The heads column is configured to distill the crude nitriles feed stream under a partial vacuum and produce a heads column overhead stream comprising HCN at the top of the heads column, and a bottom liquid stream comprising acrylonitrile product at the bottom of the heads column. The heads column comprises a condenser that is configured to condense the heads column overhead stream. The apparatus comprises a glandless pump in the overhead system. The pump is configured to pump at least a portion of the heads column overhead stream as a reflux stream to the heads after the heads column overheard stream is condensed in the condenser.
Abstract:
A process and system for acrylonitrile and HCN recovery includes a heads column system operated to reduce heads column condenser duty and reduce equipment while maintaining required purity and specifications with minimal increases in reboiler duty. In one aspect, the process includes providing a feed stream that includes acrylonitrile, HCN and water to a heads column; distilling the feed stream in the heads column to produce a heads column overhead stream that includes HCN and a bottom liquid stream that includes acrylonitrile; removing a sidestream from a side draw of the heads column that includes water and organics; separating at least some water and organics from the sidestream to provide an organic stream; returning the organic stream to the heads column; and adjusting a ratio of an amount of sidestream removed from a side draw of the heads column to an amount of organic stream returned to the heads column below the side draw to provide the bottom liquid stream with 500 ppm or less HCN.
Abstract:
An ammoxidation reactor includes an outer ring of sets of multistage cyclones suspended in the reactor. Each multistage set of cyclones includes a first stage cyclone having a first stage inlet configured to receive a reactor stream flowing up from a fluidized catalyst bed in the reactor and separate at least a portion of catalyst from the reactor stream. A ratio of square meter of first stage inlet area per square meter of available cross sectional area of the reactor is about 0.03 to about 0.05. An ammoxidation process includes reacting a hydrocarbon stream in a fluidized catalyst bed in a reactor to produce a reactor stream. The process further includes separating catalyst from the reactor stream in an outer ring of sets of multistage cyclones, each multistage set of cyclones including a first stage cyclone having a first stage inlet configured to receive a reactor stream flowing up from a fluidized catalyst bed in the reactor and separate at least a portion of catalyst from the reactor stream. A ratio of cyclone inlet velocity in meters/second to a reactor effluent velocity in meters/second is 15 or greater.
Abstract:
Control of a reaction temperature occurring inside an ammoxidation reactor is achieved by controlling a flowrate of superheated steam allowed to bypass superheat cooling coils of the cooling system of the reactor in response to a measured reaction temperature. In another aspect, control of the reaction temperature is achieved by controlling a pressure inside a steam drum used to supply the superheated steam used for cooling purposes.
Abstract:
Replacement of different sections of the feed sparger used in a commercial ammoxidation reactor is facilitated by using gas-tight quick-disconnect fittings to attach various sections of the sparger to one another as well as to the wall of the reactor. In addition, the diameters of the lateral conduits in these sparger sections, as well as the diameters of the feed nozzles attached to these laterals, are varied to facilitate uniform flow of feed gas through these components. The sparger can be subdivided into multiple feed sparger section arranged for better reactor control. Finally, the end caps terminating the distal ends of the sparger lateral conduits can be provided with nozzles for removal of any ammoxidation catalyst that may have inadvertently reached the sparger interior.
Abstract:
An apparatus comprises a heads column, the heads column configured to receive a crude nitriles feed stream and to distill the crude nitriles feed stream and produce a heads column overhead stream comprising HCN at the top of the heads column, and a heads bottom liquid stream comprising acrylonitrile product at the bottom of the heads column. The apparatus comprises an overhead system comprising a condenser, the condenser configured to condense the heads column overhead stream. The apparatus comprises an acid addition system. The acid addition system is configured to add an acid to an inlet to maintain a predetermined concentration of acid in an HCN final product, and to maintain a predetermined concentration of acid in the heads column bottom liquid.