• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Process for the co-production of methanol and urea from a hydrocarbon feed without venting large amounts of carbon dioxide to the atmosphere.
    公开号:AU2012364340A1
    申请号:U2012364340
    申请日:2012-12-21
    公开日:2014-07-24
    发明作者:Juul Per DAHL
    申请人:Haldor Topsoe AS；
    IPC主号:C01B3-02
    专利说明:
    WO 2013/102589 PCT/EP2012/076667 1 Title: CO-PRODUCTION OF METHANOL AND UREA The present invention relates to a process for the co production of methanol and urea from a hydrocarbon feed. 5 More particularly the invention is concerned with a sequen tial and once-through (single pass) process for the produc tion of methanol and urea product from a hydrocarbon con taining feed stock by means of primary and secondary re forming, intermediary methanol and ammonia formation and 10 conversion of the ammonia to urea product in a single proc ess train, with a much reduced production of excess of car bon dioxide and hydrogen. Production of urea by conversion of ammonia and carbon di 15 oxide is a well known process and conventionally employed in the industry. It is further known from US patent application No. 2010/0133472 to co-produce methanol and ammonia from syn 20 thesis gas with reduced production of excess of carbon di oxide and hydrogen. It is the general object of the invention to provide a process for co-producing methanol and urea with much re 25 duced production of excess of carbon dioxide and hydrogen from a hydrocarbon feed stock. The term "much reduced production of excess of carbon diox ide and hydrogen" shall be understood in such a manner that 30 conversion of the hydrocarbon feed stock to synthesis gas is performed at conditions to provide a substantially stoichiometric synthesis gas for the production of methanol WO 2013/102589 PCT/EP2012/076667 2 and urea, resulting in emission of carbon dioxide and hy drogen only as required for purging of inert gases from the co-production of methanol and urea. 5 The general object of the invention is achieved when per forming the production of synthesis gas in a combined steam and carbon dioxide primary hydrocarbon reforming step and a secondary reforming secondary step with oxygen enriched air. 10 Accordingly, the invention provides a process for co producing methanol and urea from a hydrocarbon feedstock comprising the sequential steps of: 15 (a) producing a synthesis gas containing hydrogen, carbon monoxide and dioxide and nitrogen by steam reforming the hydrocarbon feedstock in a primary reforming stage and sub sequently in a secondary reforming stage; 20 (b) subjecting the synthesis gas from step (a) to a partial water gas shift; (c) removing at least part of the carbon dioxide from the synthesis gas from step (b); 25 (d) catalytically converting the carbon monoxide, carbon dioxide and hydrogen of the synthesis gas from step (c) in a once-through methanol synthesis stage and withdrawing an effluent containing methanol and a gaseous effluent con 30 taining nitrogen, hydrogen and unconverted carbon monoxide and carbon dioxide; WO 2013/102589 PCT/EP2012/076667 3 (e) subjecting the gaseous effluent from step (d) to cata lytic methanation to remove the unconverted carbon monoxide and carbon dioxide; 5 (f) catalytically converting the nitrogen and hydrogen in the gaseous effluent from step (e) in an ammonia synthesis stage and withdrawing an effluent containing ammonia; and (g) passing at least part of the ammonia containing efflu 10 ent to an urea synthesis stage and converting the ammonia in the effluent to urea product by reaction with at least part of the carbon dioxide being removed from the synthesis gas in step (c), 15 wherein a part of the carbon dioxide obtained in step (c) is recycled to the primary reforming stage in step (a), and/or wherein the secondary reforming stage in step (a) is operated with oxygen enriched air. 20 As used herein the term "partial water gas shift of the synthesis gas" means that a part of synthesis gas is by passed the water gas shift reaction and combined with the shifted synthesis gas after the reaction. 25 As further used herein the term "primary reforming stage" means reforming being conducted in a conventional steam methane reformer (SMR), i.e. tubular reformer with the heat required for the endothermic reforming being provided by radiation heat from burners, such as burners arranged along 30 the walls of the tubular reformer.
    WO 2013/102589 PCT/EP2012/076667 4 As also used herein the term "secondary reforming stage" means reforming being conducted in an autothermal reformer or catalytic partial oxidation reactor. 5 As further used herein, the term "once-through methanol synthesis stage" means that methanol is produced in at least one catalytic reactor operating in a single pass con figuration, i.e. without significant recirculation (not more than 5%) of the volume flow of any gas produced in the 10 methanol synthesis back to the at least one methanol reac tor of the methanol synthesis stage, particularly the gas effluent containing hydrogen and unconverted carbon oxides. Suitable hydrocarbon feed stocks for use in the invention 15 include methane, natural gas, naphtha and higher hydrocar bons. Preferably the hydrocarbon feedstock comprises methane, for instance in the form of natural gas, liquefied natural gas 20 (LNG) or substitute natural gas (SNG). When employing naphtha and higher hydrocarbons, it is pre ferred to subject these feed stocks to a prereforming step prior to the primary reforming stage. However, prereforming 25 can be employed for all types of hydrocarbon feed stock. By the invention we make direct use of the reactions gov erning reforming, methanol synthesis, ammonia synthesis and urea synthesis so that methanol and urea can be co-produced 30 without venting carbon dioxide being removed from the sec ondary reformed synthesis gas.
    WO 2013/102589 PCT/EP2012/076667 5 By the process according to the invention the amount of carbon dioxide and carbon monoxide in the synthesis gas from step (b), minus the amount of carbon dioxide recycle from step(c) to step(a), fulfils the stoichiometric re 5 quired amount in the methanol synthesis reaction and the urea reaction: CO + 2 H 2 = CH 3 0H C02 + 3 H 2 = CH 3 0H + H 2 0 10 2NH 3 + C02 = (NH 2 ) 2CO + H 2 0 At the same time the amount of hydrogen and nitrogen in the synthesis gas from step (a) matches the stoichiometric re quired amounts in both the above methanol synthesis reac 15 tions and the ammonia synthesis: 2N 2 + 3H 2 = 2NH 3 This means that the molar content of H 2 , CO, C02 in the 20 synthesis gas from step (b) shall fulfil the relation:
    M(H
    2 ) = 3*M(N 2 ) + 2*M(CO) + 3*(M(CO 2
    )-M(N
    2 )-REC) where REC is the molar C02 recycle flow from step (c) to 25 step (a). This is obtained, when controlling the primary steam re forming reactions: 30 CH 4 + H 2 0 = CO + 3H 2 ; and
    CH
    4 + 2H 2 0 = C02 + 4H 2 WO 2013/102589 PCT/EP2012/076667 6 and/or the partial oxidation with oxygen enriched air in the subsequent secondary steam reforming:
    CH
    4 + 1/202 = CO + 2H 2 5 and the water-gas-shift reaction:
    H
    2 0 + CO = C02 + H 2 10 To maintain the required amounts of carbon monoxide, carbon dioxide and hydrogen in the final synthesis gas, a con trolled amount of carbon dioxide removed from the gas may be recycled to the primary reforming stage to suppress the shift reaction in order to avoid a production of hydrogen 15 and carbon dioxide in excess of the required amounts to be used in the methanol, ammonia and urea synthesis. The secondary reforming is conducted in a secondary re former or autothermal reformer with oxygen enriched air in 20 order to provide for the required amount of nitrogen for the ammonia synthesis and the required amount of carbon monoxide, carbon dioxide and hydrogen for the methanol syn thesis together with required amount of carbon dioxide nec essary for carbon dioxide recycle to the primary reformer 25 and the conversion of ammonia to urea. Final control of the carbon monoxide/carbon dioxide ratio to meet the required amount of nitrogen, carbon monoxide, carbon dioxide and hydrogen for the methanol and ammonia 30 synthesis together with required amount of carbon dioxide necessary for carbon dioxide recycle to the primary re former and the conversion of ammonia to urea, is obtained WO 2013/102589 PCT/EP2012/076667 7 by subjecting part of the synthesis gas to the water gas shift reaction prior to the removal af carbon dioxide in step (c). 5 The final synthesis gas is by the above measures adjusted to contain carbon monoxide, carbon dioxide, hydrogen and nitrogen in a molar ratio substantially complying to the stoichiometric amounts in the methanol synthesis and in the ammonia synthesis and to provide the necessary amount of 10 carbon dioxide for use in the urea synthesis and optionally for use in the primary reforming stage. Thus, in a preferred embodiment of the invention the molar content of H2, CO, C02, and N2 in the synthesis gas from 15 the partial shift in step (b) fullfill the following rela tion I, within 10% accuracy: I: M(H 2 ) = 3*M(N 2 ) + 2*M(CO) + 3* (M(CO 2
    )-M(N
    2 )-REC) 20 where REC is the molar C02 recycle flow from step (c) to step (a). The relation I is obtained by recycling carbon dioxide from step (c) to the primary reforming stage in step (a) and/or 25 by operating the secondary reforming stage in step (a) with oxygen enriched air and/or by partial shift of the synthe sis gas from step (a). The process of the present invention is environmentally 30 friendly because there are no emissions to the surroundings of the C02 removed from secondary reformed synthesis gas. Practically all carbon monoxide (and carbon dioxide) pro- WO 2013/102589 PCT/EP2012/076667 8 duced in the process is used for methanol and the urea syn thesis, beside small amounts of carbon dioxide which are vented to the atmosphere in purge gas. 5 Removal of carbon dioxide from the secondary reformed syn thesis gas may be performed by any conventional means in a physical or chemical wash as known in the art. Preferably, carbon dioxide is removed by the known Bene 10 field process, which allows easy recovery of absorbed car bon dioxide for use in the urea synthesis and optionally for recycle to the primary reforming stage, as discussed above. 15 The methanol synthesis stage is preferably conducted by conventional means by passing the synthesis gas at high pressure and temperatures, such as 60-150 bar and 150-300'C through at least one methanol reactor containing at least one fixed bed of methanol catalyst. A particularly pre 20 ferred methanol reactor is a fixed bed reactor cooled by a suitable cooling agent such as boiling water, e.g. boiling water reactor (BWR). In a specific embodiment the methanol synthesis stage in step (d) is conducted by passing the synthesis gas through a series of one or more boiling water 25 reactors and subsequently through an adiabatic fixed bed reactor. Preferably the one or more boiling water reactor is in the form of a single reactor of the condensing methanol type which comprises within a common shell a fixed bed of methanol catalyst particles and cooling means 30 adapted to indirectly cooling the methanol synthesis gas with a cooling agent, and which preferably operates at pressures above 90 bar and below 150 bar, more preferably WO 2013/102589 PCT/EP2012/076667 9 above 110 bar and below 130 bar, as described in our DK patent applications PA 2008 00261 and PA 2008 00260 filed 25 February 2008. The use of a methanol reactor according to these applications enables operation at pressures much 5 higher than conventional boiling reactors which typically are about 80 to 90 bar. In addition it enables the use of a single reactor rather than two conventional boiling water reactors, thereby significantly reducing plant costs. Fur thermore, since the operating pressure in the methanol syn 10 thesis stage can be kept as high as about 120 bar or even higher there are significant savings in terms of equipment size and overall investment costs as methanol synthesis is favoured at high pressures. 15 Accordingly, the invention enables the operation of the methanol and ammonia synthesis section at similar operating pressures, for instance 130 bar, which implies a simplified process with significant savings in size of equipment as mentioned above. Yet it is also possible to operate at two 20 different operating pressures, for instance 80-90 bar in the methanol synthesis stage and 130 bar in the ammonia synthesis stage, which implies energy savings in the metha nol synthesis stage. 25 In step (d) the effluent containing methanol is preferably a liquid effluent. This effluent is obtained by cooling and condensation of the synthesis gas from the methanol reac tors. Accordingly the process of the invention may further comprise cooling the synthesis gas withdrawn from each 30 methanol reactor to condense methanol and passing the gas through a separator, withdrawing a bottom fraction from the separator containing the raw methanol, withdrawing an over- WO 2013/102589 PCT/EP2012/076667 10 head fraction containing synthesis gas which is passed to the subsequent methanol reactor, and forming a single liq uid effluent containing methanol by combining the bottom fractions of the separators of each reactor containing the 5 raw methanol. It would be understood that the term "methanol reactor" as used herein encompasses adiabatic fixed bed reactors and cooled reactors such as boiling water reactors and reactors 10 of the condensing-methanol type which comprises within a common shell a fixed bed of methanol catalyst particles and cooling means adapted to indirectly cooling the methanol synthesis gas with a cooling agent adiabatic fixed bed re actors. 15 In step (e) the catalytic methanation stage for conversion of carbon monoxide to methane is conducted in at least one methanation reactor, which is preferably an adiabatic reac tor containing a fixed bed of methanation catalyst. 20 In step (f) the ammonia synthesis gas from the methanation stage containing the correct proportion of hydrogen and ni trogen (H 2
    :N
    2 molar ratio of 3:1) is optionally passed through a compressor to obtain the required ammonia synthe 25 sis pressure, such as 120 to 200 bar, preferably about 130 bar. Ammonia is then produced in a conventional manner by means of an ammonia synthesis loop comprising at least one ammonia converter containing at least one fixed bed of am monia catalyst, with interbed cooling. Ammonia may be re 30 covered from the effluent containing ammonia as liquid am monia by condensation and subsequent separation. Prefera bly, an off-gas stream containing hydrogen, nitrogen and WO 2013/102589 PCT/EP2012/076667 11 methane is withdrawn from the ammonia synthesis stage, as also is a hydrogen-rich stream (> 90 vol% H 2 ) . These streams may for instance stem from a purge gas recovery unit. Preferably, this hydrogen stream is added to the 5 methanol synthesis stage (step (c)), for instance by com bining with the methanol synthesis gas. The recycle of this hydrogen-rich stream enables a higher efficiency in the process as useful hydrogen is utilised in the methanol syn thesis and subsequent ammonia synthesis rather than simply 10 being used as fuel. In order to improve the energy efficiency of the process the off-gas stream containing hydrogen, nitrogen and meth ane of step (e) is returned to step (a), i.e. it is re 15 turned as off-gas fuel to the reforming section of the plant, specifically to the primary reforming stage. The ammonia being withdrawn from the ammonia synthesis is then converted to the urea product by reaction with carbon 20 dioxide recovered from step (c) as described above. By the invention part of the ammonia can be withdrawn as an ammonia product which alters relation I as follows: 25 II: M(H 2 ) = 3*M(N 2 ) + 2*M(CO) + 3*(M(CO 2
    )-M(N
    2 )+2*P-REC) where P is the molar ammonia product from step (f).
    权利要求:
    Claims (7)
    [1] 4. Process according to anyone of claims 1 to 3, wherein 25 the carbon dioxide is recycled to the primary reforming stage in step (a) in an amount to obtain a molar ratio of carbon dioxide to methane of 0.0 to 0.43.
    [2] 5. Process according to anyone of claims 1 to 4, wherein 30 the secondary reforming step is performed with the oxygen enriched air and wherein the oxygen enriched air contains ambient content of oxygen up to 99.5 vol% pure oxygen. WO 2013/102589 PCT/EP2012/076667 14
    [3] 6. Process according to anyone of claims 1 or 5 wherein the methanol synthesis stage in step (d) is conducted by pass ing the synthesis gas through a series of one or more boil ing water reactors and subsequently through an adiabatic 5 fixed bed reactor.
    [4] 7. Process according to claim 6, wherein the one or more boiling water reactor is in the form of a single reactor of the condensing-methanol type which comprises within a com 10 mon shell a fixed bed of methanol catalyst particles and cooling means adapted to indirectly cooling the methanol synthesis gas with a cooling agent.
    [5] 8. Process according to claim 6 or 7, further comprising 15 cooling the synthesis gas withdrawn from each methanol re actor to condense methanol and passing the gas through a separator, withdrawing a bottom fraction from the separator containing the raw methanol, withdrawing an overhead frac tion containing synthesis gas which is passed to the subse 20 quent methanol, and forming a single liquid effluent con taining methanol by combining the bottom fractions of the separators of each reactor containing the raw methanol.
    [6] 9. Process according to anyone of the preceding claims, 25 wherein an off-gas stream containing hydrogen, nitrogen and methane is employed as fuel for heating the primary reform ing stage in step (a).
    [7] 10. Process according of anyone of the preceding claims, 30 wherein the hydrocarbon feed stock is subjected to pre reforming upstream of step (a).
    类似技术:
    公开号 | 公开日 | 专利标题
    US9085513B2|2015-07-21|Co-production of methanol and urea
    CA2686034C|2015-04-28|Co-production of methanol and ammonia
    CA2859678C|2019-07-30|Process for producing ammonia and urea
    EP2199254A1|2010-06-23|Integrated gas refinery
    DK2723676T3|2019-02-25|PROCEDURE FOR MANUFACTURING AMMONIAK AND UREA
    US20180258019A1|2018-09-13|Method and apparatus for improving the efficiency of reforming process for producing syngas and methanol while reducing the co2 in a gaseous stream
    US8692034B2|2014-04-08|Co-production of methanol and ammonia
    AU2016261285A1|2017-11-23|A novel method for methanol synthesis
    OA16947A|2016-01-25|Co-production of methanol and urea.
    WO2021170625A1|2021-09-02|Co-production of methanol, ammonia and urea
    US20220048853A1|2022-02-17|Process for the production of urea formaldehyde concentrate
    CN110831893A|2020-02-21|Combined production of methanol and ammonia
    US20220048854A1|2022-02-17|Process for the production of urea formaldehyde concentrate
    CN110831892A|2020-02-21|Process and catalyst for producing ammonia synthesis gas
    同族专利:
    公开号 | 公开日
    WO2013102589A1|2013-07-11|
    AR089633A1|2014-09-03|
    US9085513B2|2015-07-21|
    KR102027913B1|2019-10-02|
    CA2860386A1|2013-07-11|
    EA201491322A1|2014-12-30|
    CN104024149B|2017-05-31|
    BR112014016436B1|2021-04-20|
    EA024553B1|2016-09-30|
    US20140357736A1|2014-12-04|
    KR20140111677A|2014-09-19|
    CA2860386C|2020-04-28|
    AP2014007727A0|2014-06-30|
    CN104024149A|2014-09-03|
    ZA201404424B|2015-12-23|
    IN2014CN04954A|2015-09-18|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2016-07-28| FGA| Letters patent sealed or granted (standard patent)|
    优先权:
    申请号 | 申请日 | 专利标题
    DKPA201200008||2012-01-04||
    DKPA201200008||2012-01-04||
    PCT/EP2012/076667|WO2013102589A1|2012-01-04|2012-12-21|Co-production of methanol and urea|
    [返回顶部]