Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
  • C01C3/00—Cyanogen; Compounds thereof
  • C01C3/02—Preparation, separation or purification of hydrogen cyanide
  • C01C3/0208—Preparation in gaseous phase
  • C01C3/0212—Preparation in gaseous phase from hydrocarbons and ammonia in the presence of oxygen, e.g. the Andrussow-process
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
  • C01C3/00—Cyanogen; Compounds thereof
  • C01C3/02—Preparation, separation or purification of hydrogen cyanide
  • C01C3/04—Separation from gases
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
  • C07C209/44—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of carboxylic acids or esters thereof in presence of ammonia or amines, or by reduction of nitriles, carboxylic acid amides, imines or imino-ethers
  • C07C209/48—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of carboxylic acids or esters thereof in presence of ammonia or amines, or by reduction of nitriles, carboxylic acid amides, imines or imino-ethers by reduction of nitriles
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C253/00—Preparation of carboxylic acid nitriles
  • C07C253/08—Preparation of carboxylic acid nitriles by addition of hydrogen cyanide or salts thereof to unsaturated compounds
  • C07C253/10—Preparation of carboxylic acid nitriles by addition of hydrogen cyanide or salts thereof to unsaturated compounds to compounds containing carbon-to-carbon double bonds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/10—Process efficiency

Definitions

• the present invention is directed to an integrated process for the reduction of one or more dinitrile compounds to form diamines.
• the present invention is directed to improving process efficiency by recovering a hydrogen stream and a hydrogen cyanide product stream from a crude hydrogen cyanide product, using the hydrogen cyanide product stream to hydrocyanate butadiene to form one or more dinitrile compounds, and using the hydrogen stream to hydrogenate the dinitrile compounds to form a diamine.
• the pressure for the dinitrile compound hydrogenation may be less than 5000 kPa.
• Butadiene also referred to as 1,3 -butadiene, is commonly used to form further industrially applicable chemicals, including adiponitrile (ADN), methylglutaronitrile (MGN), ethylsuccinonitrile (ESN) and synthetic rubbers.
• ADN adiponitrile
• MGN methylglutaronitrile
• ESN ethylsuccinonitrile
• Butadiene may be prepared by numerous processes, including extraction from C4 hydrocarbons, dehydrogenation of n-butane, and from butenes, butanediols, and ethanol.
• ADN and/or MGN from butadiene, butadiene is hydrocyanated using a nickel catalyst and a boron promoter.
• ADN is generally prepared by this method
• ADN may alternatively be prepared by the methods disclosed in Integrated Organic Chemistry, Weissermel et al. 1997, pp. 245-250, by chlorinating butadiene to form 1,4-dichlorobutene, which is reacted with sodium cyanide to form 1,4-dicyanobutene, which is then hydrogenated to ADN, or by hydrodimerizing acrylonitrile.
• ADN may serve as an intermediate for the production of 6-aminocapronitrile (ACN), hexamethylenediamine (HMD), and combinations thereof.
• ACN may be cyclized to form caprolactam which may be used as an intermediate for Nylon-6.
• HMD is produced on an industrial scale as an intermediate for products in the industrial, textile, resin, carpet and coating sectors. Additionally, HMD may be used in coatings, curing agents, petroleum additives, adhesives, inks, scale and corrosion inhibitors, and water treatment chemicals.
• HMD is as an intermediate for forming hexamethylene diisocyanate via phosgenation, commonly used in polyurethane manufacturing, and as an intermediate for nylon, including Nylon-6,6, Nylon-6, 10, and Nylon-6, 12, among other nylons of the formula Nylon-6,x, wherein x is the number of carbons in the diacid.
• HMD may be commercially prepared by hydrogenating ADN under pressure, at elevated temperature, by mixing ADN with an excess of ammonia and hydrogen, and passing the mixture through a catalyst bed comprising copper, nickel or cobalt, with or without a support.
• the elevated temperature may range from 85 to 150°C and the pressure may range from 200 to 500 atms. (See e.g., U.S. Patent No. 3,398,195).
• MGN may serve as an intermediate for the production of methylpentamethylenediamine (MPMD), also referred to as 2-methylpentamethylenediamine.
• MPMD is produced on an industrial scale, and may be used in plastics, films, fibers, adhesives, epoxy curing agents, water treatment processes, and as an intermediate to prepare polyamides or to prepare ⁇ -picoline.
• ⁇ - picoline is used as an intermediate in the preparation of nicotinamide.
• MGN is hydrogenated under pressure in the presence of a Raney cobalt or Raney nickel catalyst to form MPMD. Under high hydrogen pressure, the hydrogenation of MGN in the presence of a nickel or Raney nickel catalyst forms a mixture of MPMD and 3-methylpiperidine (MPP). The pressure may be less than 50 bars, e.g., from 10 to 35 bars. (See e.g., U.S. Patent No. 8,247,561).
• HMD hydrogen cyanide
• ADN butadiene
• MGN hydrogen cyanide
• HCN hydrogen cyanide
• BMA BMA process
• HCN can be commercially produced by reacting ammonia with a methane-containing gas and an oxygen-containing gas at elevated temperatures in a reactor in the presence of a suitable catalyst (U.S. Patent Nos. 1,934,838; and 6,596,251).
• Sulfur compounds and higher homologues of methane may have an effect on the parameters of oxidative ammonolysis of methane. See, e.g., Trusov, Effect of Sulfur Compounds and Higher Homologues of Methane on Hydrogen Cyanide Production by the Andrussow Method, Russian J. Applied Chemistry, 74:10 (2001), pp. 1693-1697).
• Unreacted ammonia is separated from HCN by contacting the reactor effluent gas stream with an aqueous solution of ammonium phosphate in an ammonia absorber. The separated ammonia is purified and concentrated for recycle to HCN conversion. HCN is recovered from the treated reactor effluent gas stream typically by absorption into water.
• the recovered HCN may be treated with further refining steps to produce purified HCN.
• Clean Development Mechanism Project Design Document Form CDM PDD, Version 3
• Purified HCN can be used in hydrocyanation, such as hydrocyanation of an olefin-containing group, or such as hydrocyanation of 1,3-butadiene and pentenenitrile, which can be used in the manufacture of ADN and/or MGN.
• HCN is synthesized from methane and ammonia in the substantial absence of oxygen and in the presence of a platinum catalyst, resulting in the production of HCN, hydrogen, nitrogen, residual ammonia, and residual methane (See e.g., Ullman's Encyclopedia of Industrial Chemistry, Volume A8, Weinheim 1987, pages 161-163).
• Commercial operators require process safety management to handle the hazardous properties of hydrogen cyanide. (See Maxwell et al. Assuring process safety in the transfer of hydrogen cyanide manufacturing technology, JHazMat 142 (2007), 677-684).
• emissions of HCN production processes from production facilities may be subject to regulations, which may affect the economics of HCN manufacturing. (See Crump, Economic Impact Analysis For The Proposed Cyanide Manufacturing NESHAP, EPA, May 2000).
• U.S. Patent No. 2,797,148 discloses the recovery of ammonia from a gaseous mixture containing ammonia and hydrogen cyanide.
• a reaction off-gas from the process of preparing hydrogen cyanide by reacting ammonia with a hydrocarbon-bearing gas and an oxygen- containing gas, comprises ammonia, hydrogen cyanide, hydrogen, nitrogen, water vapor and carbon oxides.
• the off-gas is cooled to a temperature of 55 to 90°C and is then led into an absorption tower for separation of ammonia from the off-gas.
• U.S. Patent No. 3,647,388 discloses a process for the manufacture of hydrogen cyanide from a gaseous hydrocarbon of up to six carbon atoms, such as methane, and ammonia.
• the preferred process is carried out in a burner having a center conduit for the flow of an oxygen bearing stream and one or more annular conduits adjacent to the center conduit for the concurrent flow of hydrogen, ammonia and the gaseous hydrocarbon, the conduits ending in a reaction chamber where the gaseous hydrocarbon and ammonia react at the flame front of the hydrogen and oxygen combustion flame.
• the process eliminates the use of a catalyst.
• the present invention is directed to a process for producing diamines comprising: (a) determining methane content of a methane-containing gas and purifying the methane-containing gas when the methane content is determined to be less than 90 vol.%; (b) reacting in a first reaction zone a ternary gas mixture comprising at least 25 vol.% oxygen in the presence of a catalyst to form a crude hydrogen cyanide product comprising hydrogen cyanide and off-gas, wherein the ternary gas mixture comprises the methane- containing gas, an ammonia-containing gas, and an oxygen-containing gas; (c) separating the crude hydrogen cyanide product to form a hydrogen cyanide product stream and an off-gas stream comprising hydrogen, water, carbon monoxide, carbon dioxide; or combinations thereof, (d) separating the off-gas stream to form a hydrogen stream, and a purge stream comprising carbon monoxide, carbon dioxide and water; (e) contacting in a second reaction zone at least a portion
• Reducing, also referred to as hydrogenating, the one or more dinitrile compounds in step (f) may be conducted at a pressure of less than 5000 kPa, and may also form at least one of 6- aminocapronitrile, 3-methylpiperidine and combinations thereof.
• the ternary gas mixture may comprise from 25 to 32 vol.% oxygen.
• the oxygen-containing gas may comprise greater than 21 vol.% oxygen, e.g., at least 80 vol.% oxygen, at least 95 vol.% oxygen or pure oxygen.
• the off-gas stream may comprise from 40 to 90 vol.% hydrogen; from 0.1 to 20 vol.%) water; from 0.1 to 20 vol.% carbon monoxide; and from 0.1 to 20 vol.% carbon dioxide.
• the off-gas stream may be separated using a pressure swing adsorber.
• the pressure swing adsorber may be operated at a pressure from 1400 kPa to 2400 kPa and at a temperature from 16 to 55°C.
• the pressure swing adsorber may comprise at least two adsorption beds.
• the first adsorption bed and second adsorption bed may each comprise at least one adsorbent.
• the hydrogen stream may comprise at least 95 vol.% hydrogen or at least 99 vol.% hydrogen.
• the hydrogen cyanide product stream may comprise less than 5 vol.% hydrogen or may be substantially free of hydrogen. At least 70% of hydrogen from the crude hydrogen cyanide product may be recovered in the hydrogen stream.
• Step (c) may further comprise separating the crude hydrogen cyanide product to form an ammonia stream.
• the ammonia stream may be returned to the reactor.
• the present invention is directed to a process for producing hexamethylenediamine comprising: (a) determining methane content of a methane-containing gas and purifying the methane-containing gas when the methane content is determined to be less than 90 vol.%; (b) reacting in a first reaction zone a ternary gas mixture in the presence of a catalyst to form a crude hydrogen cyanide product comprising hydrogen cyanide and off-gas, (c) separating the crude hydrogen cyanide product to form a hydrogen cyanide product stream and a hydrogen stream comprising hydrogen; (d) contacting in a second reaction zone at least a portion of the hydrogen cyanide product stream of step (c) with butadiene to hydrocyanate butadiene to form one or more dinitrile compounds; and (e) contacting in a third reaction zone at least a portion of the hydrogen stream of step (c) with the one or more dinitrile compounds to hydrogenate the one or more dinitrile compounds to form
• the ternary gas mixture may comprise methane, ammonia, and at least 25 vol.% oxygen.
• the reduction pressure may be less than 5000 kPa, e.g., less than 4000 kPa.
• the one or more dinitrile compounds may be selected from the group consisting of adiponitrile, methylglutaronitrile, and combinations thereof.
• the present invention is directed to a process for producing hexamethylenediamine comprising: (a) determining methane content of a methane-containing gas and purifying the methane-containing gas when the methane content is determined to be less than 90 vol.%; (b) reacting in a first reaction zone a ternary gas mixture in the presence of a catalyst to form a crude hydrogen cyanide product comprising hydrogen cyanide and off-gas; (c) separating the crude hydrogen cyanide product to form a hydrogen cyanide product stream and a hydrogen stream comprising hydrogen; (d) contacting in a second reaction zone at least a portion of the hydrogen cyanide product stream of step (c) with butadiene to hydrocyanate butadiene to form adiponitrile; and (e) contacting in at least a third reaction zone at least a portion of the hydrogen stream of step (c) with adiponitrile to reduce the adiponitrile to form hexam
• Reducing, also referred to as hydrogenating, adiponitrile in step (e), upon reduction, may also form 6-aminocapronitrile.
• the ternary gas mixture may comprise from 25 to 32 vol.% oxygen.
• the oxygen-containing gas may comprise greater than 21 vol.% oxygen, e.g., at least 80 vol.% oxygen, at least 95 vol.% oxygen or pure oxygen.
• the off-gas stream may comprise from 40 to 90 vol.% hydrogen; from 0.1 to 20 vol.% water; from 0.1 to 20 vol.% carbon monoxide; and from 0.1 to 20 vol.% carbon dioxide.
• the off-gas stream may be separated using a pressure swing adsorber.
• the pressure swing adsorber may be operated at a pressure from 1400 kPa to 2400 kPa and at a temperature from 16 to 55 °C.
• the pressure swing adsorber may comprise at least two adsorption beds.
• the first adsorption bed and second adsorption bed may each comprise at least one adsorbent.
• the hydrogen stream may comprise at least 95 vol.% hydrogen or at least 99 vol.% hydrogen.
• the hydrogen cyanide product stream may comprise less than 5 vol.% hydrogen or may be substantially free of hydrogen. At least 70% of hydrogen from the crude hydrogen cyanide product may be recovered in the hydrogen stream.
• Step (c) may further comprise separating the crude hydrogen cyanide product to form an ammonia stream.
• the ammonia stream may be returned to the reactor.
• the present invention is directed to a process for producing methylpentamethylenediamine comprising: (a) determining methane content of a methane- containing gas and purifying the methane-containing gas when the methane content is determined to be less than 90 vol.%; (b) reacting in a first reaction zone a ternary gas mixture in the presence of a catalyst to form a crude hydrogen cyanide product comprising hydrogen cyanide and off-gas; (c)separating the crude hydrogen cyanide product to form a hydrogen cyanide product stream and a hydrogen stream comprising hydrogen; (d) contacting in a second reaction zone at least a portion of the hydrogen cyanide product stream of step (c) with butadiene to hydrocyanate butadiene to form methylglutaronitrile; and (e) contacting in at least a third reaction zone at least a portion of the hydrogen stream of step (c) with methylglutaronitrile to reduce the methylglutaronitrile to form
• the ternary gas mixture may comprise from 25 to 32 vol.% oxygen.
• the oxygen-containing gas may comprise greater than 21 vol.% oxygen, e.g., at least 80 vol.% oxygen, at least 95 vol.% oxygen or pure oxygen.
• the off-gas stream may comprise from 40 to 90 vol.% hydrogen; from 0.1 to 20 vol.% water; from 0.1 to 20 vol.% carbon monoxide; and from 0.1 to 20 vol.% carbon dioxide.
• the off-gas stream may be separated using a pressure swing adsorber.
• the pressure swing adsorber may be operated at a pressure from 1400 kPa to 2400 kPa and at a temperature from 16 to 55°C.
• the pressure swing adsorber may comprise at least two adsorption beds.
• the first adsorption bed and second adsorption bed may each comprise at least one adsorbent.
• the hydrogen stream may comprise at least 95 vol.% hydrogen or at least 99 vol.% hydrogen.
• the hydrogen cyanide product stream may comprise less than 5 vol.% hydrogen or may be substantially free of hydrogen. At least 70% of the hydrogen from the crude hydrogen cyanide product may be recovered in the hydrogen stream.
• Step (c) may further comprise separating the crude hydrogen cyanide product to form an ammonia stream.
• the ammonia stream may be returned to the reactor.
• FIG. 1 is a schematic representation of an integrated HMD and/or MPMD production system.
• the present invention provides a process for integrating the production of diamines with a process for producing HCN.
• the HCN process includes recovering a hydrogen stream and recovering HCN.
• Each of the hydrogen and HCN may then be integrated with a diamine production system, e.g., a system for producing at least one of HMD, MPMD and combinations thereof.
• the system may include a first reaction zone to produce HCN, a second reaction zone for the hydrocyanation of butadiene to form one or more dinitrile compounds, e.g., ADN, MGN, and combinations thereof, and a third reaction zone to reduce, e.g., to hydrogenate, the one or more dinitrile compounds to form a diamine, e.g., HMD, MPMD, and combinations thereof.
• hydrogen in the prior art may be recovered from steam reforming of methane. Hydrogen obtained in this manner may have numerous contaminants that are then introduced into each process in which the hydrogen is used.
• the hydrogen recovered from the HCN process using the inventive process described herein is of a high purity and does not introduce impurities into further processes.
• current processes require numerous feed streams and/or reaction systems to produce diamines. Thus, by integrating these systems, improved process efficiency and cost savings are achieved.
• HMD formation of HMD
• HMD is formed under elevated temperature and under pressure in the presence of a catalyst, optionally in the presence of ammonia.
• the ADN hydrogenation to form HMD may be conducted at low pressure, e.g., at a pressure of less than 5000 kPa, or less than 4000 kPa. Unless otherwise indicated as gauge, all pressures are absolute. In some embodiments, the low pressure may range from 1000 to 3500 kPa, as is described in U.S. Patent No. 8,247,561.
• the catalyst may include cobalt, nickel, iron and precious metals, including ruthenium, rhenium, platinum and palladium. In some embodiments, the catalyst comprises nickel or cobalt.
• the catalyst may be on a support, including an alumina support.
• Conversion of ADN may range from 80 to 100% and may have a selectivity to HMD and/or 6-aminocapronitrile (ACN) from 95 to 99%. In some embodiments, conversion of ADN may exceed 98%). It is understood that the ratio of HMD to ACN formed may be controlled by adjusting residence time and/or other process conditions. Conversion of ADN is calculated as follows:
• ADN conversion (%) (initial ADN moles - final ADN moles) x 100
• HMD selectivity (%) (HMD mole formed) x 100
• ACN selectivity(%) (ACN mole formed) x 100
• ADN may be partially hydrogenated to form ACN, which may then be converted to caprolactam for synthesis of Nylon-6, as is described in U.S. Patent No. 5,900,511, the entire contents and disclosures of which is hereby incorporated by reference.
• ADN may be formed through the following 2-step process:
• butadiene is hydrocyanated to a mixture of 3-pentenenitrile (“3PN”) and 2-methyl-3-butenenitrile (“2M3BN”).
• 3PN is then hydrocyanated to form ADN and/or MGN.
• Each hydrocyanation step may be catalyzed by a nickel catalyst, preferably a zero valent nickel catalyst. Examples of such catalysts are described in U.S. Patent No. 8,088,943, the entirety of which is hereby incorporated by reference.
• the hydrocyanation of 3PN may be in the presence of a Lewis acid co-catalyst, also described in U.S. Patent No. 8,088,943.
• the reaction may be carried out in the liquid phase at a pressure from 500 to 51,000 kPa, e.g., from 1000 to 50,000 kPa, and at a temperature from 0 to 200°C, e.g., from 50 to 100°C.
• MPMD The formation of MPMD may be represented by the following formula:
• MPMD is formed under elevated temperature and under pressure in the presence of a catalyst and optionally in the presence of ammonia.
• the elevated temperature may range from 60 to 160°C, e.g., from 80 to 140°C.
• the MGN hydrogenation to form MPMD may be conducted at low pressure, e.g., at a pressure of less than 5000 kPa, or less than 4000 kPa.
• the low pressure may range from 1000 to 3500 kPa, as is described in U.S. Patent No. 8,247,561.
• the catalyst may include cobalt and, as doping elements, chromium and nickel. [0028] Conversion of MGN may range from 95 to 100% and may have a selectivity to MPMD and/or MPP from 94 to 99%. In some embodiments, conversion of MGN may exceed 98%).
• MGN conversion (%) (initial MGN moles - final MGN moles) x 100 initial MGN moles
• Hydrogen cyanide for the hydrocyanation of butadiene and 3PN, may be obtained from the Andrussow or BMA processes.
• the Andrussow process for forming HCN methane, ammonia and oxygen raw materials are reacted at temperatures above 1000°C in the presence of a catalyst to produce a crude hydrogen cyanide product comprising HCN, hydrogen, carbon monoxide, carbon dioxide, nitrogen, residual ammonia, residual methane, and water.
• These components, i.e., the raw materials are provided to the reactor as a ternary gas mixture comprising an oxygen-containing gas, an ammonia-containing gas and a methane-containing gas.
• the source of the methane may vary and may be obtained from renewable sources such as landfills, farms, biogas from fermentation, or from fossil fuels such as natural gas, oil accompanying gases, coal gas, and gas hydrates as further described in VN Parmon, "Source of Methane for Sustainable Development", pages 273- 284, and in Derouane, eds. Sustainable Strategies for the Upgrading of Natural Gas: Fundamentals, Challenges, and Opportunities (2003).
• the methane purity and the consistent composition of the methane-containing source is of significance.
• the process may comprise determining methane content of the methane-containing source and purifying the methane-containing source when the methane content is determined to be less than 90 vol.%.
• Methane content may be determined using gas chromatograph-based measurements, including Raman Spectroscopy. The methane content may be determined continuously in real time or as needed when new sources of methane-containing sources are introduced into the process.
• the methane- containing source may be purified when the methane content is above 90 vol.%, e.g., from 90 to 95 vol.%.
• Known purification methods may be used to purify the methane-containing source to remove oil, condensate, water, C2+ hydrocarbons (e.g., ethane, propane, butane, pentane, hexane, and isomers thereof), sulfur, and carbon dioxide.
• C2+ hydrocarbons e.g., ethane, propane, butane, pentane, hexane, and isomers thereof
• Natural gas is typically used as the source of methane while air, oxygen-enriched air, or pure oxygen can be used as the source of oxygen. Preferably oxygen-enriched air or pure oxygen is used.
• the ternary gas mixture is passed over a catalyst to form a crude hydrogen cyanide product.
• the crude hydrogen cyanide product is then separated to recover HCN. In the present invention, the crude hydrogen cyanide product is also separated to recover hydrogen.
• air refers to a mixture of gases with a composition approximately identical to the native composition of gases taken from the atmosphere, generally at ground level. In some examples, air is taken from the ambient surroundings. Air has a composition that includes approximately 78 vol.% nitrogen, 21 vol.% oxygen, 1 vol.% argon, and 0.04 vol.% carbon dioxide, as well as small amounts of other gases.
• oxygen-enriched air refers to a mixture of gases with a composition comprising more oxygen than is present in air.
• Oxygen-enriched air has a composition including greater than 21 vol.% oxygen, less than 78 vol.% nitrogen, less than 1 vol.%) argon and less than 0.04 vol.% carbon dioxide.
• oxygen-enriched air comprises at least 28 vol.% oxygen, e.g., at least 80 vol.% oxygen, at least 95 vol.% oxygen, or at least 99 vol.% oxygen.
• Natural gas refers to a mixture comprising methane and optionally ethane, propane, butane, carbon dioxide, oxygen, nitrogen, and/or hydrogen sulfide. Natural gas may also comprise trace amounts of rare gases including helium, neon, argon and/or xenon. In some embodiments, natural gas may comprise less than 90 vol.% methane.
• the crude hydrogen cyanide product comprises the components of air, e.g., 78 vol.% nitrogen, and the nitrogen produced in the ammonia and oxygen side reaction.
• the crude hydrogen cyanide product contains the HCN and also by-product hydrogen, methane combustion byproducts (carbon monoxide, carbon dioxide, water), residual methane, and residual ammonia.
• air i.e., 21 vol.% oxygen
• the presence of the inert nitrogen renders the residual gaseous stream with a fuel value that may be lower than desirable for energy recovery.
• the use of oxygen-enriched air or pure oxygen instead of air in the production of HCN provides several benefits, including the ability to recover hydrogen. Additional benefits include an increase in the conversion of natural gas to HCN and a concomitant reduction in the size of process equipment.
• the use of oxygen-enriched air or pure oxygen reduces the size of the reactor and at least one component of the downstream gas handling equipment through the reduction of inert compounds entering the synthesis process.
• the use of oxygen-enriched air or pure oxygen also reduces the energy consumption required to heat the oxygen-containing feed gas to reaction temperature.
• the crude hydrogen cyanide product is formed using oxygen-enriched air or pure oxygen, it is desirable to process the off-gas from the crude hydrogen cyanide product to recover the hydrogen content rather than burn the off-gas in a boiler.
• the off-gas may be separated from the crude hydrogen cyanide product using an absorber.
• the hydrogen can be recovered from at least a portion of the off-gas using pressure swing adsorption (PSA), membrane separation, or other known purification/recovery methods.
• PSA pressure swing adsorption
• membrane separation membrane separation
• a PSA unit is used to recover hydrogen.
• the gas is first compressed from 130 kPa to 2275 kPa, e.g., from 130 kPa to 1700 kPa, or from 136 kPa to 1687 kPa, and is then sent to the PSA unit.
• the high purity recovered hydrogen is more valuable as an ingredient than as a fuel and as such may be used as a feed stream to another process such as in the hydrogenation of ADN to 6-aminocapronitrile and/or HMD or in the hydrogenation of MGN to MPMD and/or MPP. It should be noted that the amount of nitrogen in the off-gas will impact the economic feasibility of recovering hydrogen from the off-gases rather than burning the off-gases in a boiler.
• compositions or ingredients can also impact the desirability of recovering hydrogen.
• the off-gas stream can be redirected to either the steam-generating boilers or to a flare rather than proceeding to hydrogen recovery.
• FIG. 1 shows an embodiment of an integrated HMD production process.
• the ternary gas mixture 105 comprises a methane-containing gas 102, an ammonia- containing gas 103, and an oxygen-containing gas 104.
• the oxygen content of the oxygen- containing gas 104 is greater than 21 vol.%, e.g., oxygen-enriched air or pure oxygen.
• the oxygen content in the oxygen-containing gas 104 is at least 28 vol.% oxygen, at least 80 vol.% oxygen, at least 95 vol.% oxygen, or at least 99 vol.% oxygen.
• the amount of oxygen present in the ternary gas mixture 105 is controlled by flammability limits. Certain combinations of air, methane and ammonia are flammable and will therefore propagate a flame following ignition. A mixture of air, methane and ammonia will burn if the gas composition lies between the upper and lower flammability limits. Mixtures of air, methane and ammonia outside of this region are typically not flammable.
• the use of oxygen- enriched air changes the concentration of combustibles in the ternary gas mixture. Increasing the oxygen content in the oxygen-containing gas feed stream significantly broadens the flammable range. For example, a mixture containing 45 vol.% air and 55 vol.% methane is considered very fuel-rich and is not flammable, whereas a mixture containing 45 vol.% oxygen and 55 vol.% methane is flammable.
• An additional concern is the detonation limit.
• a gas mixture containing 60 vol.% oxygen, 20 vol.% methane and 20 vol.% ammonia can detonate.
• the oxygen-enriched air or pure oxygen feed is controlled to form a ternary gas mixture within the flammable region, but not within the detonable region.
• the ternary gas mixture 105 comprises at least 25 vol.% oxygen, e.g., at least 28 vol.% oxygen.
• the ternary gas mixture comprises from 25 to 32 vol.% oxygen, e.g., from 26 to 30 vol.% oxygen.
• the ternary gas mixture may have a molar ratio of ammonia-to-oxygen from 1.2 to 1.6, e.g., from 1.3 to 1.5, a molar ratio of ammonia-to-methane from 1 to 1.5, e.g., from 1.10 to 1.45, and a molar ratio of methane-to- oxygen of 1 to 1.25, e.g., from 1.05 to 1.15.
• a ternary gas mixture may have a molar ratio of ammonia-to-oxygen of 1.3 and methane-to-oxygen 1.2.
• the ternary gas mixture may have a molar ratio of ammonia-to-oxygen of 1.5 and methane-to-oxygen of 1.15.
• the oxygen concentration in the ternary gas mixture may vary depending on these molar ratios.
• HCN production occurs in a first reaction zone.
• the ternary gas mixture 105 is fed to the reactor 106 where it is passed over a catalyst to form a crude hydrogen cyanide product 107.
• the catalyst is typically a wire mesh platinum/rhodium alloy or a wire mesh platinum/iridium alloy.
• Other catalyst compositions can be used and include, but are not limited to, a platinum group metal, platinum group metal alloy, supported platinum group metal or supported platinum group metal alloy.
• Other catalyst configurations can also be used and include, but are not limited to, porous structures including woven, non-woven and knitted configurations, wire gauze, tablets, pellets, monoliths, foams, impregnated coatings, and wash coatings.
• the crude hydrogen cyanide product 107 is cooled in a heat exchanger afterto exiting the reactor.
• the crude hydrogen cyanide product 107 is cooled from up to 1200°C to less than 400°C, less than 300°C or less than 250°C.
• Exemplary crude hydrogen cyanide product compositions are shown below in Table 1.
• preparing HCN using the air process only produces 13.3 vol.% hydrogen, while the oxygen process results in an increased hydrogen concentration of 34.5 vol.%.
• the amount of hydrogen may vary depending on oxygen concentration of the feed gases and ratios of reactants, and may range from 34 to 36 vol.% hydrogen.
• oxygen concentration of the crude hydrogen cyanide product is low, preferably less than 0.5 vol.%), and higher amounts of oxygen in the crude hydrogen cyanide product may trigger shut down events or necessitate purging.
• the crude hydrogen cyanide product formed using the Oxygen Andrussow Process may vary as shown in Table 2.
• the crude hydrogen cyanide product is then separated, using an absorber 110, to form an off-gas stream 111 comprising hydrogen, water, carbon dioxide and carbon monoxide; and a hydrogen cyanide product stream 112, comprising hydrogen cyanide.
• the hydrogen cyanide product stream comprises less than 10 vol.% hydrogen, e.g., less than 5 vol.% hydrogen, less than 1 vol.% hydrogen, less than 100 mpm hydrogen, or is substantially free of hydrogen.
• a comparison of the off-gas stream 1 11 after separation from the crude hydrogen cyanide product 107, for the oxygen Andrussow process and for the air Andrussow process, and the amount of nitrogen in each of such processes is tabulated below in Table 3.
• the off-gas stream 111 comprises greater than 80 vol.% hydrogen.
• the off-gas stream 111 comprises from 40 to 90 vol.% hydrogen, e.g., from 45 to 85 vol.% hydrogen or from 50 to 80 vol.% hydrogen.
• the off-gas stream 11 may further comprise from 0.1 to 20 vol.% water, e.g., from 0.1 to 15 vol.% water or from 0.1 to 1 vol.%> water.
• the off-gas stream 111 may further comprise from 1 to 20 vol.% carbon monoxide, e.g., from 1 to 15 vol.% carbon monoxide or from 1 to 10 vol.% carbon monoxide.
• the off-gas stream 111 may further comprise from 0.1 to 20 vol.% carbon dioxide, e.g., from 0.5 to 15 vol.% carbon dioxide or from 0.75 to 2 vol.% carbon dioxide.
• the off-gas stream 111 comprises 78 vol.% hydrogen, 12 vol.% carbon monoxide, 1 vol.% carbon dioxide and the balance of water and hydrogen cyanide.
• the off-gas stream 111 may also comprise trace amounts of dinitriles, and small amounts of additional components, including methane, ammonia, nitrogen, argon and oxygen. Preferably, these additional components are present at a total of less than 10 vol.%>.
• the amount of nitrogen is less than 20 vol.%, e.g., less than 15 vol.%, or less than 10 vol.%.
• the off-gas stream 111 may be separated using a PSA unit 130.
• a typical PSA process and apparatus is described in U.S. Pat. Nos. 3,430,418 and 3,986,849, the entireties of which are hereby incorporated by reference.
• the PSA 130 may comprise at least two beds, e.g., at least 3 beds or at least 4 beds, and is operated at a pressure from 1400 kPa to 2400 kPa, e.g., from 1600 kPa to 2300 kPa or from 1800 kPa to 2200 kPa.
• the PSA 130 is operated at a temperature from 16 to 55°C; e.g. from 20 to 50°C or from 30 to 40°C.
• the PSA may be a polybed PSA.
• Each bed comprises adsorbents.
• each bed comprises the same adsorbents.
• each bed comprises different adsorbents.
• the adsorbents may be conventional adsorbents used in PSA units, including zeolites, activated carbon, silica gel, alumina, and combinations thereof.
• the cycle time through each bed may range from 150 to 210 seconds, e.g., from 180 to 200 seconds and the total cycle time may range from 300 seconds to 1000 seconds, e.g., 400 seconds to 900 seconds.
• the off-gas stream 111 is separated in PSA 130 to form a hydrogen stream 132 and a purge stream 131.
• the hydrogen stream 132 may be considered a high purity hydrogen stream and comprises at least 95 vol.% hydrogen, e.g., at least 99 vol.% hydrogen or at least 99.5 vol.% hydrogen.
• the purge stream 131 comprises carbon dioxide, carbon monoxide, water and hydrogen. The purge stream 131 may be burned as fuel. Hydrogen stream 132 is discussed further herein.
• Recovering hydrogen by using a PSA 130 allows at least 70% hydrogen from the crude hydrogen cyanide product 107 made using the oxygen Andrussow process to be recovered, e.g., at least 72.5%, at least 75% or at least 76%.
• the crude hydrogen cyanide product 107 may optionally be subjected to further processing steps prior to separation of the off-gas from the crude hydrogen cyanide product 107.
• the Andrussow process when practiced at optimal conditions, has potentially recoverable residual ammonia in the hydrogen cyanide product stream. Because the rate of HCN polymerization increases with increasing pH, residual ammonia must be removed to avoid the polymerization of the HCN. HCN polymerization represents not only a process productivity problem, but an operational challenge as well, since polymerized HCN can cause process line blockages resulting in pressure increases and associated process control problems.
• ammonia removal unit 108 which may include scrubbers, strippers, and combinations thereof. At least a portion of crude hydrogen cyanide product 107 is directed to ammonia scrubbers, absorbers and combinations thereof 108, to remove residual ammonia.
• the crude hydrogen cyanide product, after ammonia removal, 109 comprises less than 1000 mpm ammonia, e.g., less than 500 mpm or less than 300 mpm.
• the ammonia stream 113 may be recycled to the reactor 106, to the ternary gas mixture 105 for re-use as a reactant feed, or to the HMD production process, described further herein.
• HCN polymerization is inhibited by immediately reacting the hydrogen cyanide stream with an excess of acid (e.g., H 2 S0 4 or H 3 P0 4 ) such that the residual free ammonia is captured by the acid as an ammonium salt and the pH of the solution remains acidic.
• an excess of acid e.g., H 2 S0 4 or H 3 P0 4
• Formic acid and oxalic acid in ammonia recovery feed stream are captured in aqueous solution in an ammonia recovery system as formates and oxalates.
• the crude hydrogen cyanide product 109 may then be separated to remove off-gas, as described herein, to form the hydrogen cyanide product stream 112.
• This stream 1 12 may be further processed in HCN refining zone 120 to recover a finished hydrogen cyanide stream 121 for hydrocyanation.
• hydrocyanation as used herein is meant to include hydrocyanation of aliphatic unsaturated compounds comprising at least one carbon-carbon double bond or at least one carbon-carbon triple bond or combinations thereof, and which may further comprise other functional groups including, but not limited to, dinitriles, esters, and aromatics.
• aliphatic unsaturated compounds include, but are not limited to, alkenes (e.g., olefins); alkynes; dienes; and functional substituted compounds thereof. Suitable dienes include 1,3- butadiene. Functional substituted compounds may include pentenenitriles. Hydrocyanation may include 1,3 -butadiene and pentenenitrile hydrocyanation to produce ADN.
• the HCN recovered from the finished hydrogen cyanide stream 121 is uninhibited HCN.
• the term "uninhibited HCN” as used herein means that the HCN is substantially depleted of stabilizing polymerization inhibitors.
• stabilizers are typically added to minimize polymerization of HCN and require at least partial removal of the stabilizers prior to utilizing the HCN in hydrocyanation of, for example, 1,3- butadiene and pentenenitrile to produce ADN.
• HCN polymerization inhibitors include, but are not limited to mineral acids, such as sulfuric acid and phosphoric acid; organic acids such as acetic acid; sulfur dioxide; and combinations thereof.
• At least a portion of the finished hydrogen cyanide stream 121 is directed to a second reaction zone, e.g., dinitrile compound production reactor 140 to produce ADN, MGN, or combinations thereof.
• a second reaction zone e.g., dinitrile compound production reactor 140 to produce ADN, MGN, or combinations thereof.
• the dinitrile compound production process may include separation equipment (not shown). If desired, dinitrile compounds may be separated to form an ADN stream and an MGN stream (not shown). See U.S. Patent No. 5,312,959.
• the one or more dinitrile compounds exit dinitrile compound production unit 140 via line 141 and are directed to third reaction zone, e.g., diamine unit 150 to form HMD, MPMD, and combinations thereof. Additionally, reduction of the one or more dinitrile compounds may form 6-aminocapronitrile, MPP, or combinations thereof.
• An optional ammonia stream may also fed to the reactor (not shown). The optional ammonia stream may be a fresh ammonia stream or may comprise at least a portion of recovered ammonia from line 113.
• At least a portion of hydrogen stream 132 is also directed to diamine reactor 150 to hydro genate the one or more dinitrile compounds to form a crude diamine product stream 151. If needed, additional hydrogen from a source external to the process may be combined with hydrogen stream 132. The hydrogen may be compressed prior to entering the reactor.
• Crude diamine product stream 151 exits diamine unit 150 and enters refining system 160, where crude diamine product stream is separated to form a diamine product 161 and a residue 162 comprising 6-aminocapronitrile, MPP, unreacted dinitrile compound, and/or reaction by-products, including tetrahydroazepine ("THA").
• THA tetrahydroazepine Separation of HMD is described in U.S. Patent No. 6,887,352, the entirety of which is hereby incorporated by reference.
• HMD product 161 comprises less than 1000 mpm THA, e.g., less than 500 mpm, less than 150 mpm, less than 20 mpm, or is substantially free of THA. If desired, the 6-aminocapronitrile may be recovered.
• MPMD can be further purified as described in U.S. Patent No. 8,247,561.
• the foregoing functions and/or process may be embodied as a system, method or computer program product.
• the functions and/or process may be implemented as computer-executable program instructions recorded in a computer-readable storage device that, when retrieved and executed by a computer processor, controls the computing system to perform the functions and/or process of embodiments described herein.
• the computer system can include one or more central processing units (i.e., CPUs), computer memories (e.g., read-only memory, random access memory), and a data storage devices (e.g., a hard disk drive).
• CPUs central processing units
• computer memories e.g., read-only memory, random access memory
• a data storage devices e.g., a hard disk drive
• the computer-executable instructions can be encoded using any suitable computer programming language (e.g., C++, JAVA, etc.). Accordingly, aspects of the present invention may take the form of an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects.
• a ternary gas mixture is formed by combining pure oxygen, an ammonia-containing gas and a methane-containing gas.
• the ammonia-to-oxygen molar ratio in the ternary gas mixture is 1.3:1 and the methane-to-oxygen molar ratio in the ternary gas mixture is from 1.2:1
• the ternary gas mixture which comprises from 27 to 29.5 vol.% oxygen, is reacted in the presence of a platinum/rhodium catalyst to form a crude hydrogen cyanide product comprising from 34 to 36 vol.% hydrogen. Hydrogen forms during the reaction.
• the crude hydrogen cyanide product is removed from the reactor and sent to an ammonia removal unit to separate residual ammonia from the crude hydrogen cyanide product.
• the crude hydrogen cyanide product is then sent to an absorber to form an off-gas and a hydrogen cyanide product stream.
• the off-gas has a composition as is shown in Table 3, Oxygen Andrussow Process, and is compressed to a pressure of 2275 kPa and is sent to a PSA unit.
• the PSA unit comprises four beds, each bed comprising activated carbon and zeolite. Each bed adsorbs non-hydrogen components in the off- gas, such as nitrogen, carbon monoxide, carbon dioxide, and water.
• the PSA is operated at a temperature of 40°C for a total cycle time of 800 seconds (approximately 190 seconds in each bed). 75 to 80%> of the hydrogen from the crude hydrogen cyanide product is recovered in a hydrogen stream.
• the hydrogen stream has a purity of 99.5% or higher.
• the hydrogen stream from Example 1 is directed to an HMD production system comprising an HMD reactor where it is used to hydrogenate ADN.
• the HMD production process is described in US Patent No. 3,398,195.
• the hydrogen stream is able to supply at least 20% of the hydrogen, on a molar basis, needed to hydrogenate ADN to form HMD.
• the hydrogen stream from Example 1 is directed to a methylglutaronitrile production system as described in US Patent No. 8,247,561.
• the hydrogen stream is able to supply at least 20% of the hydrogen, on a molar basis, needed to hydrogenate methylglutaronitrile to form methylpentamethylenediamine. Comparative Example A
• Example 1 An off-gas is separated as indicated in Example 1, except that air is used instead of pure oxygen to form the ternary gas mixture. Thus the ternary gas mixture would have less than 25 vol.% oxygen.
• the ammonia separation equipment is larger in size than the equipment used in Example 1, and the absorber is larger than in Example 1 due to the increased amount of nitrogen as compared to Example 1.
• the off-gas composition is shown in Table 1, Air Andrussow Process.
• the off-gas is compressed and sent to the PSA unit used in Example 1.
• the number of compressors is eight times larger than the number of compressors required to compress the off-gas in Example 1. After the non-hydrogen components are adsorbed in the first bed, the PSA is no longer able to operate due to an insufficient volume of hydrogen. It is not be economically or energetically feasible to recover hydrogen.
• the hydrogen is not be integrated with HMD and/or methylpentamethylenediamine production.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• General Health & Medical Sciences (AREA)
• Inorganic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=49881132

Family Applications (1)

Country Status (4)

Cited By (2)

Families Citing this family (1)

Citations (2)

• 2013
  • 2013-12-12 WO PCT/US2013/074668 patent/WO2014099610A1/en active Application Filing
  • 2013-12-12 TW TW102145779A patent/TW201425277A/zh unknown
  • 2013-12-12 CN CN201310682047.6A patent/CN103864623B/zh active Active
• 2014
  • 2014-12-17 HK HK14112626.1A patent/HK1199016A1/zh unknown

Patent Citations (2)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events