[go: up one dir, main page]

WO2016198367A1 - Procédé et conception de réacteur de production d'ammoniac à l'aide de membranes sélectives pour l'ammoniac - Google Patents

Procédé et conception de réacteur de production d'ammoniac à l'aide de membranes sélectives pour l'ammoniac Download PDF

Info

Publication number
WO2016198367A1
WO2016198367A1 PCT/EP2016/062827 EP2016062827W WO2016198367A1 WO 2016198367 A1 WO2016198367 A1 WO 2016198367A1 EP 2016062827 W EP2016062827 W EP 2016062827W WO 2016198367 A1 WO2016198367 A1 WO 2016198367A1
Authority
WO
WIPO (PCT)
Prior art keywords
ammonia
gas
membrane system
membrane
converter
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2016/062827
Other languages
English (en)
Inventor
Poul Erik Højlund NIELSEN
Burcin Temel MCKENNA
Peter Mølgaard Mortensen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Topsoe AS
Original Assignee
Haldor Topsoe AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Haldor Topsoe AS filed Critical Haldor Topsoe AS
Publication of WO2016198367A1 publication Critical patent/WO2016198367A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
    • C01C1/00—Ammonia; Compounds thereof
    • C01C1/02—Preparation, purification or separation of ammonia
    • C01C1/04—Preparation of ammonia by synthesis in the gas phase
    • C01C1/0405—Preparation of ammonia by synthesis in the gas phase from N2 and H2 in presence of a catalyst
    • C01C1/0458—Separation of NH3
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
    • B01D53/228—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2257/00—Components to be removed
    • B01D2257/40—Nitrogen compounds
    • B01D2257/406—Ammonia
    • 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
    • Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
    • 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
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • the present invention relates to a process and a reactor design for ammonia production using ammonia selective membranes. More specifically, a membrane system is used which consists of one or more low temperature, high pressure am ⁇ monia selective membranes with an ammonia/H 2 selectivity of at least 4. Such ammonia selective membranes may be mem- branes consisting of polymer-based organic materials, but they may alternatively be membranes based on inorganic ma ⁇ terials .
  • the synthesis is carried out in a circulatory system commonly known as an ammonia synthesis loop. Only a fraction of the synthesis gas is converted per pass, as limited by the equilibrium concentration of N3 ⁇ 4 at the exit conditions of the converter.
  • the make-up gas fed to the loop will contain about 99% of nitrogen and hydrogen in a molar ratio H 2 / 2 of around 3.0 with about 1% methane and argon besides minor amounts of other molecules, some of which may be catalyst poisons .
  • the catalytic activity of an ammonia catalyst may be re ⁇ prised in the presence of certain chemical compounds (poi ⁇ sons) . These may be gaseous, occurring as minor components of the synthesis gas, or they may be solids introduced as impurities to the catalyst during the manufacturing pro ⁇ cess.
  • the deactivation of the ammonia catalyst is dependent on the operating conditions (pressure and temperature) , but more significantly on the small amounts of gaseous com ⁇ pounds contained in the feed gas. It is therefore impera- tive that such compounds are removed from the feed gas and that a feed gas with low N3 ⁇ 4 content to be fed to the con ⁇ verter is obtained.
  • the average lifetime of an ammonia synthesis catalyst has increased markedly since the early days of ammonia manufac ⁇ ture due to a number of process improvements.
  • One of these is the incorporation of a secondary ammonia condensation system, in which the make-up gas together with the recycle gas is washed in liquid ammonia before entering the ammonia synthesis converter.
  • a secondary ammonia condensation system in which the make-up gas together with the recycle gas is washed in liquid ammonia before entering the ammonia synthesis converter.
  • the process starts from a hydrogen and nitrogen containing feed, wherein (a) the feed is fed into a recycle circuit stream, the recycle circuit comprising at least one reactor in which ammonia is formed from hydrogen and nitrogen, and (b) the ammonia is abstracted from the recycle circuit stream leaving the reactor, after which the recycle circuit stream is fed back to the reactor. Furthermore (c) the re ⁇ cycle circuit incorporates a membrane unit, which is perme ⁇ able at least to ammonia.
  • the recycle circuit stream is passed through the membrane unit on one side of the mem ⁇ brane and the feed is passed through the membrane unit on the other side of the membrane in such a way that at least ammonia from the recycle circuit stream is incorporated in ⁇ to the feed.
  • Figs. 2 and 3 of EP 1 083 150 Al show a recycle circuit op ⁇ erating at pressures and temperatures similar to those of the present invention, with a pressure differential across the ceramic membrane of between 25 and 350 bar, the recycle circuit forming the x high pressure side' and the feed side forming the x low pressure side' .
  • the operation temperature is from -10°C to 100°C.
  • the action of the membrane ensures that ammonia in the recycle gas diffuses through the mem ⁇ brane, thereby lowering the concentration of ammonia in the recycle circuit stream to the inlet of the reactor. This results in an increased ammonia production.
  • the membrane is placed be ⁇ tween the recycle gas and the make-up gas, either before (Fig.
  • the gas is cooled after the first compressor step and the ammonia is condensed out together with i.a. water.
  • the make-up gas, now containing ammonia is sent to the second compressor step, and from there it moves on to be mixed with the exit gas from the converter to the separator.
  • the make-up gas stream is about 5 times smaller than the recycle gas stream, and the partial pressure difference will soon be very small. This means that only a limited amount of the ammonia will be captured via the membrane.
  • EP 1 083 150 Al The process steps and the advantages obtained according to EP 1 083 150 Al are rather similar to those of the present invention, but the EP publication only discloses use of a ceramic membrane, not a polymeric membrane or a combined polymeric/ceramic membrane.
  • the membranes described in EP 1 083 150 Al are not described as being low temperature or high temperature membranes, nor is the ammonia/H2 selectiv ⁇ ity of these membranes described.
  • US 4.758.250 A discloses a process for ammonia separation using polymeric ion exchange membranes and sorbents from an ammonia synthesis plant recycle loop gas. It is not clearly stated where the membrane is located in the recycle loop.
  • EP 0 293 736 A2 describes the separation of ammonia from mixtures containing ammonia and other gases, such as nitro ⁇ gen and hydrogen, using semipermeable ion exchange polymeric membranes and sorbents.
  • the active materials in said semipermeable membranes may also be used as selective N3 ⁇ 4 sorbents for the recovery of ammonia from such mixtures.
  • US 6.065.306 discloses a method of producing a pu ⁇ rified, pressurized ammonia stream from a feed stream com- prising ammonia, moisture and other impurities. The method is more focused on treatment of the ammonia exiting the converter than on the removal of residual ammonia from the recycle gas .
  • the previously suggested applications of polymer-based am ⁇ monia selective membranes have mainly looked at the ammonia membrane as an alternative to the removal of ammonia based on condensation, which is used today. However, this is a dubious way of using the membrane.
  • the system proposed with the pre ⁇ sent invention includes the best of the previous practice along with a new membrane system.
  • the present invention is based on the idea that the mem ⁇ brane system is to be placed at a point after cooling and condensing of the ammonia, thereby both removing impurities from the gas and obtaining a feed gas with low N3 ⁇ 4 content to be fed to the converter.
  • possible membrane types to separate the residual N3 ⁇ 4 from N 2 , H 2 , CH 4 and Ar in the recycle gas of an ammonia plant have been horr ⁇ gated.
  • the purpose was to be able to increase the ammonia production in the synthesis loop.
  • the inorganic mate ⁇ rials are recommended for high temperature applications, whereas the polymers are suitable for low temperature ap ⁇ plications.
  • the target tempera- ture is 0 to 35°C.
  • - Membrane stability For the purposes of the invention, stability against high pressure is very important. This can be achieved by depositing the membrane polymer on a porous support and then topping the membrane surface with a non ⁇ selective and very permeable polymer layer to prevent cracking or pinhole formation on the selective membrane layer .
  • - Membrane selectivity Especially the ammonia/H 2 selectiv ⁇ ity should minimum be 4.
  • the present invention relates to a process for ammo ⁇ nia production by separating residual N3 ⁇ 4 from N 2 , H 2 , CH 4 and Ar in the recycle gas of an ammonia plant in a membrane system, wherein the separation is carried out in the recycle line of an ammonia converter with the membrane system located at a point after cooling and condensing of the ammonia, there ⁇ by both removing impurities from the gas and obtaining a feed gas with low N3 ⁇ 4 content to be fed to the converter, wherein the membrane system consists of one or more low temperature, high pressure ammonia selective membranes with an ammonia/H 2 selectivity of at least 4, said ammonia se- lective membranes consisting of polymer-based organic mate ⁇ rials, and wherein N3 ⁇ 4 on the permeate side is removed by pumping or with the aid of a sweep gas.
  • N3 ⁇ 4 is removed either by pumping to ensure a constant and low pressure of N3 ⁇ 4 or with a sweep gas consisting of ei ⁇ ther CO 2 , N 2 , H 2 0, ethane, propane, butane, pentane or any combination of these.
  • the invention further relates to a reactor design for ammonia production, said design comprising at least one ammonia converter (AC), a heat exchanger (Hex2), a loop waste heat boiler (w) , a loop boiler feedwater preheater (bfw) , a compressor (C) and a membrane system (MS) .
  • the reactor design according to the invention is shown in the figure, which illustrates a part of the ammonia synthe ⁇ sis loop.
  • the membrane system would most suitably be locat ⁇ ed at a low temperature part of the ammonia synthesis loop before the gas arrives to the compressor (C) and the heat exchanger (Hex2) .
  • the gas is cold after having passed a first heat exchanger (Hexl) .
  • it is preferably located after the compressor, which condenses the ammonia in the gas before the gas enters the heat ex- changer (Hex2) .
  • the figure shows this latter possible loca ⁇ tion of the membrane system (MS) .
  • Organic polymer-based membranes can be used at low tempera ⁇ tures, which provide somewhat higher permeance selectivi- ties of N3 ⁇ 4 in comparison to the inorganic membranes.
  • the higher permeability of N3 ⁇ 4 in polymers results from its solubility in salts and ionic polymers. 2 and 3 ⁇ 4, which are less polar, are less soluble.
  • a potential problem when using these polymer membranes could be their stability un- der high pressures (180-190 bar) . However, this problem can be circumvented by depositing the polymer onto a mi- croporous support with large pores to avoid mass transfer limitations.
  • the feed gas to the converter is com- pressed in a recirculation compressor to a pressure of 18.6 MPa and a temperature of 40 °C.
  • the ammonia content is typi ⁇ cally in the order of 4 vol% corresponding to a partial pressure of 0.75 MPa.
  • the feed gas is introduced into a membrane unit in which the ammonia is removed down to a partial pressure of 0.2 MPa corresponding to 1 vol% in the feed gas.
  • the ammonia from the membrane is cooled and compressed and then sent to the product ammonia tank.
  • the resulting feed gas is more reactive, and thus the inlet temperature to the converter can be lowered by 10-20 °C.
  • the higher conversion per pass will also result in a smaller flow, which may be used either to be able to use smaller converters or alternatively to reduce the synthesis pres ⁇ sure .
  • Example 2 A residual recycle gas contains about 4% N3 ⁇ 4, 66% 3 ⁇ 4, 22%
  • the gas Before arriving to the compressor (C) , the gas has a temperature between 0 and 35°C under a pressure of 186 bar. After the compressor, the gas passes the membrane system (MS) , and a heat exchanger (Hex) heats the gas to 232 °C. Then the gas enters the ammonia converter (AC) , where the exit composition from the converter is found to be 17.8% NH 3 , 53.4% H 2 , 17.8% N 2 , 6.3% CH 4 and 2.9% Ar . The exit gas is then cooled to condense the ammonia, and the residual gas is recycled into the converter.
  • MS membrane system
  • Hex heat exchanger

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Analytical Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)

Abstract

Selon l'invention, dans un procédé de production d'ammoniac par séparation de NH3 résiduel à partir de N2, de H2, de CH4 et d'Ar dans le gaz de recyclage d'une usine d'ammoniac dans un système de membrane, la séparation est effectuée dans la ligne de recyclage d'un convertisseur d'ammoniac avec le système de membrane situé au niveau d'un point après le refroidissement et la condensation de l'ammoniac. De cette manière, les impuretés sont éliminées du gaz, et un gaz d'alimentation à faible teneur en NH3 à alimenter au convertisseur est obtenu. Le système de membrane se compose d'une ou de plusieurs membranes sélectives pour l'ammoniac sous haute pression, à basse température, avec une sélectivité pour l'ammoniac/H2 d'au moins 4, et le NH3 du côté perméat est éliminé par pompage ou à l'aide d'un gaz d'entraînement.
PCT/EP2016/062827 2015-06-11 2016-06-07 Procédé et conception de réacteur de production d'ammoniac à l'aide de membranes sélectives pour l'ammoniac Ceased WO2016198367A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DKPA201570361 2015-06-11
DKPA201570361 2015-06-11

Publications (1)

Publication Number Publication Date
WO2016198367A1 true WO2016198367A1 (fr) 2016-12-15

Family

ID=56101480

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2016/062827 Ceased WO2016198367A1 (fr) 2015-06-11 2016-06-07 Procédé et conception de réacteur de production d'ammoniac à l'aide de membranes sélectives pour l'ammoniac

Country Status (1)

Country Link
WO (1) WO2016198367A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0130846A2 (fr) * 1983-07-05 1985-01-09 Foster Wheeler Energy Corporation Procédé pour la production d'ammoniac
US4758250A (en) * 1987-06-01 1988-07-19 Air Products And Chemicals, Inc. Ammonia separation using ion exchange polymeric membranes and sorbents
US5455016A (en) * 1994-08-31 1995-10-03 Air Products And Chemicals, Inc. Membrane-assisted process to produce ammonia
EP1083150A1 (fr) * 1999-09-10 2001-03-14 Continental Engineering B.v. Procédé et dispositif pour la production d'ammoniac dans un circuit fermé utilisant des membranes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0130846A2 (fr) * 1983-07-05 1985-01-09 Foster Wheeler Energy Corporation Procédé pour la production d'ammoniac
US4758250A (en) * 1987-06-01 1988-07-19 Air Products And Chemicals, Inc. Ammonia separation using ion exchange polymeric membranes and sorbents
US5455016A (en) * 1994-08-31 1995-10-03 Air Products And Chemicals, Inc. Membrane-assisted process to produce ammonia
EP1083150A1 (fr) * 1999-09-10 2001-03-14 Continental Engineering B.v. Procédé et dispositif pour la production d'ammoniac dans un circuit fermé utilisant des membranes

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
TRICOLI V ET AL: "Ammonia selective hollow fibers", JOURNAL OF MEMBRANE SCIENCE, ELSEVIER BV, NL, vol. 104, no. 1, 15 August 1995 (1995-08-15), pages 19 - 26, XP004041319, ISSN: 0376-7388, DOI: 10.1016/0376-7388(94)00208-G *

Similar Documents

Publication Publication Date Title
EP0009385B1 (fr) Procédé de production de méthanol
CA1107479A (fr) Procede de synthese de l'ammoniac a partir d'azote et d'hydrogene
CA3223160A1 (fr) Craquage d'ammoniac pour hydrogene vert
Padinjarekutt et al. Na+-gated nanochannel membrane for highly selective ammonia (NH3) separation in the Haber-Bosch process
CA3006900C (fr) Procede permettant d'obtenir du dioxyde de carbone pour la synthese de l'uree
CA2522599C (fr) Procede de traitement d'un melange gazeux comprenant du propane et du propylene
US8829059B2 (en) Processes for the production of methanol using sweep-based membrane separation steps
EA028109B1 (ru) Способ разделения газов для получения водорода посредством автотермического риформинга природного газа с извлечением углекислого газа
US20040255778A1 (en) Psa sharing
JPH09511509A (ja) メタノールの製造方法
US20170081186A1 (en) Treatment method for separating carbon dioxide and hydrogen from a mixture
CA2772971A1 (fr) Procede de separation de l'ammoniac et du dioxyde de carbone de solutions aqueuses
CA1129626A (fr) Methodes pour separer au moins un gaz d'un melange gazeux par l'intermediaire de deux etages d'impregnation en serie
CA2205364A1 (fr) Azote d'une tres grande purete obtenu par separation par membrane
EA024085B1 (ru) Способ и установка для производства мочевины
WO2016198367A1 (fr) Procédé et conception de réacteur de production d'ammoniac à l'aide de membranes sélectives pour l'ammoniac
AU2013295271B2 (en) Concentration of the urea solution in a process for the synthesis of urea
JPH0733253B2 (ja) アンモニア及びメタノールの併産方法
US10508079B2 (en) Method for purification of a CO2 stream
WO2019052824A1 (fr) Procédé pour la production d'ammoniac
CN101648105B (zh) 采用金属钯膜分离技术从焦炉煤气中提取高纯度氢气的方法
NL1013016C2 (nl) Werkwijze en inrichting voor het bereiden van ammoniak in een kringloopstroom onder toepassing van keramische membranen.
JP7677476B2 (ja) アンモニア水の製造方法
KR20010031158A (ko) 가스 투과에 의한 에틸렌의 분리방법
CN120607264A (zh) 一种氨合成的膜反应器方法以及装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16727208

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16727208

Country of ref document: EP

Kind code of ref document: A1