• 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:
    A process for the synthesis of urea from ammonia and carbon dioxide in which high yield reaction and optimal reactor heat balance control are achieved at the same time by using two reaction zones, where two different NH3/CO2 molar ratios are maintained, and by treating the effluent from the second reaction zone in a separation treatment in two steps in series; the reactant gas stream discharged from the second treatment step is recycled, after partial condensation, to the first reaction zone, while at least part of the gas stream discharged from the first treatment step is recycled directly to the second reaction zone, the gas stream from both the first and second treatment step being so controlled as to obtain optimal NH3/CO2 ratios and optimal reaction temperatures in the two reaction zones.
    公开号:SU1428191A3
    申请号:SU823494195
    申请日:1982-09-20
    公开日:1988-09-30
    发明作者:Зарди Умберто
    申请人:Аммония Казале С.А. (Фирма)；
    IPC主号:
    专利说明:


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    The invention relates to amino compounds, in particular to an improved method for producing urea. The aim of the invention is to reduce steam consumption.
    Figures 1-4 are flow diagrams showing the implementation of the proposed method. (The letter R denotes the entire synthesis zone — reaction soHg, and the letters STR refer to the entire separation flow treatment zone leaving R).
    The entire reaction zone R is divided into at least two reaction zones: R, where the reaction between fresh reagents N (denoting
    fresh NHj stream) and Ci (denoting fresh CO2 stream) and recycled stream (gas + liquid) С + Lt
    (or L, with G / 1 0) at the molar ratio (NHj / COz) /, pressure P, temperature TC and get urea with a conversion of Q4; RH, g De, the reaction of synthesis of a stream of Si from P is obtained with the possible addition of fresh raw material of ammonia N7 and / or carbon dioxide Cj at a molar ratio () pressure Pj, temperature TE and output Qj. The stream flowing from the second reaction zone Pr is further subjected to a quantitative treatment of STP, also in two stages of decomposition of the carbamate and isolation of unreacted compounds, consisting of: stage E, where for a given working pressure P & and temperature T3 (except for the residence time) some gas G is allocated, its bulk is recycled as stream G g directly to the second stage of the reaction R, the rest of Cr, if any, is directed along the RC circuit and / or directly to the first Zone R (;. Stage Eg, in which the flow Sj from the first treatment zone E ;, is treated at pressure P, temperature T4, preferably in countercurrent with fresh carbon dioxide Cr to regenerate all remaining unreacted materials Cj, which after partial condensation intoEj (operating at pressure PS and temperature TS with possible addition of fresh ammonia N3) is recycled as a vapor-liquid mixture С-h + L to the first reaction zone R (. In another embodiment, condensation in Ej can be complete (C4 O, recycling RS , Bd) and part
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    vapor G (C s) is sent directly to the first reaction zone R4, Flows S (from Eg is usually then treated to E, where the desired final product Sj is separated, and the Lg solution is recycled to condenser E.
    According to the proposed method, it is possible to achieve a completely isobaric scheme, where P Pg Pj PA Pb, or preferably a non-isobaric scheme. For a non-isobaric scheme, for advantages of maximum efficiency and flexibility, RZ and EI can be maintained at the same pressure P Pg P3 and P, E2 and EZ at the same pressure P P, P PS, moreover P above P, therefore high pressure P support only a small part of the installation, which significantly saves energy consumption and installation cost,
    At the same time, at high pressure Pi, a high value of the ratio (NHj / COa.) Z is chosen to achieve the highest yields.

    In accordance with the main features of the invention, since the processing for the decomposition and release of compounds that have reacted to EI and Er is quantitative, this treatment is controlled so that both the first (E () and the second (E E) stages it was possible to directly obtain non-gas streams (C) and (Gj), which are separately directed to the second and first reaction zones, providing optimal ratios (NHj / COj) and (NHj / COj) and optimal heat balances to achieve maximum yields and desired reaction rate euraty,
    Example 1, Non-isobaric regimen (FIG. 2, Table 1)
    In the first reaction zone Ri, operating in the P mode, 160 atm and Ti 182 ° C, 32.32 mol HH3 (stream N / I) are fed at 40 ° C and the liquid – vapor mixture G + LI containing 20 mol CO2, 30 , 68 mol NHi, 6 mol HjO at 174 ° C; the molar ratio (NHj / COz) i is 3.2, and the conversion at the output of Q CO2 to urea is 60%. The urea solution Sx entering the second reaction zone Rj therefore consists of 12 moles of urea, 8 moles of CO2, 40 moles of NHs and 18 moles of Ng (
    The second reaction zone operating in the PZ 185 atm mode and T 192 ° C, except for the Si solution from the first input zone, for example, through the P. pump to overcome the pressure difference (from P, 160 atm to PI 185 atm), serves G i i vapors at TBE C, containing 2.2 mol C02 and 36 mol NHi and 1 mol NgO, coming from the first treatment stage E, also operating at 185 atm and Tj In the second reaction zone, Kg molar ratio ( NHj / CO2 = j is 4.5 and the yield of CO2 = 75%. A solution of urea Sj containing 16.66 mol of urea, 5.54 mol of CO2, 66.68 mol of Schz and 23.66 mol of HjO goes to the first treatment stage E (where, at PA Pt, 185 atm and Tj are separated. 2, 2 mol of COi, 36 mol of NHj and 1 mol of HgO, which are sent directly to the second reaction zone of Pr. I CTBOP Sa, containing 16.66 mol of urea, 3, 34 mol of CO, 30.68 mol of NHj and 22.66 mol of HgO , is fed to the second stage of processing, Her, operating at P PI of 160 atm and T / i 185 s, where using 16.66 mol of CO2 in a countercurrent (indicated by Cr), 1.84 mol of CO2, 27, are taken from the urea solution 48 mol NHa and 2 mol HgO.
    The gas coming from Ej and containing 18.5 mol of CO2, 47.48 mol of NHi and 2 mol of NgO, enters the condenser E3 (carbamate condenser), into which the solution SE - 1.5 also enters. moles of CO2, 3.2 moles of NHj, and 4 moles of NgO, coming from the final processing system E, where the last traces of COg and HjO, still contained in the solution of Zl, drained from Er, are finally separated. The mixed phase (vapors + carbamate solution) + LI at 160 atm and 175 C, which is formed in the condenser Ej, is recirculated under the action of gravity to the first reaction zone RA. It contains 20 moles of CO2, 30.68 moles of NHi and 6 moles of HjO.
    Isobaric mode (Fig. 3, Table 2).
    In the first reaction zone R4, operating at P 160 atm and T5 180 C, 25.82 mol NHj (stream Nt) are fed at and the mixture of liquid - vapor Gi + L «, containing 21 mol CO, 37.18 mol NHj and 6 mol NgO at 175 ° C; the molar ratio (NHj / COa) i is 3,
    and the conversion of C02 to urea is 57%. RiCTBOp of urea S ,, which is fed to the second reaction zone R, thus consists of 12 mol of urea, 9 mol of CO2, 39 mol of Schz, and 18 mol of NgO.
    In the second reaction zone RZ, operating at Pr pp 160 atm and Tj 190 ° C, in addition to the solution Si of the first reaction zone RI, the pairs Gch with, containing 2.8 moles of CO2, 24.7 moles of NHa and 1 moles of NgO, are supplied from the first stage of treatment, E, also operating at P Pg P “16 atm and at Te 194 s.
    At the second reaction zone Rt, 7.5 mol NHj (stream Nt) is also fed at 40 s, the molar ratio (NHj) / C0 g) is 4; COg Q2 conversion is 70%.
    Urea solution 3g, containing 16.66 mol of urea, 7.14 mol of COg, 61.88 mol of NHj and 23.66 mol of H (0, is fed to the first treatment stage E, where, at RE, Prg 160 atm and Tz the stream C is separated , with this stream containing 2.8 moles of SOe, 24.7 moles of NHj and 1 mole of HjtO, is fed directly to the second reaction zone Rj .. thief Sj, containing 16.66 moles of urine, 4.34 moles of CO2, 37.19 mol Shz and 22.66 mol HgO, are fed to the second stage of treatment Eg, operating at P4 RH PI 160 atm and T4 185 C, where, using a flow of Cg containing 16.66 mol Cr in countercurrent, is taken from the urea solution, 2 , 84 mol C02, 33.98 mol NHj and 2 mol NgO. Gas Gj, waste with E, consisting of 19.50 mol CO2, 33.98 mol NHj and 2 mol NgO at P4 PS Р ≈ 160 atm and at 190 s are fed to the EZ condenser (carbon mat condenser) which is also fed with a solution of LI consisting of 1.5 mol of COt, 3.2 mol of NHj and 4 mol of HjO discharged from the final processing system. Sf, where the last traces of CO2 and HgO are finally separated, still remaining in the solution from stage Ej. The displaced phase (vapors + carbamate solution) G4 + + L "at 160 atm and 175 ° C, which is formed in stage E, is recycled to the first reaction zone R. It contains 21 mol CO2, 37.18 mol NHj, 6 mol NgO. . All streams circulate in the isobaric system under the influence of gravity.
    51
    . Non-pressure mode (full condensation in the condenser) carbamate (Fig. 4, Table 3).
    As in Example 1, however, with full condensation, part of the recycled vapors sent to the first reaction zone R, while the rest of the recycled vapors are recycled directly to the reactor,
    In this case, only the solution is cyclized. From the condenser Ej to the reactor, without the vapor phase LJ (C 0), and to the condenser only part of the gas C3 is fed, part of which Gj is fed directly to the reactor.
    The total steam balance (1 kg per 1 ton of urea) is shown in Table. four.
    As can be seen from the table. 4, the proposed method makes it possible to reduce steam consumption to 1997–2055 kg per 1 ton of urea versus 3179 kg in the known method.
    权利要求:
    Claims (1)
    [1]
    Invention Formula
    A method of producing urea by reacting ammonia and carbon dioxide at elevated temperature and pressure, an excess of ammonia in two synthesis zones, to produce a melt containing urea, ammonium carbamate, water, ammonia, carbon dioxide, which is subjected to two-stage distillation with a gas phase return first distillation step to z91.9.
    On the synthesis and direction of the liquid phase of the first stage to the second stage of distillation, which is carried out in a stream of carbon dioxide to produce a gas phase, which is condensed and sent to the synthesis zone, and a liquid phase containing urea, characterized in that, in order to reduce steam consumption, the interaction of ammonia and carbon dioxide is carried out successively in two zones — the first zone at a molar ratio of (3-3.2): 1, ISO-ISZ C temperature and pressure of 160 atm and in the second zone at a molar ratio of (4- 4,5): 1, the temperature is 190-196 C and the pressure is 160-185 atm. dosing the streams from two distillation steps so as to ensure the indicated ratios of reactants and temperatures in the reaction zones, with one part of the gas phase of the second distillation step containing ammonia and carbon dioxide being fully condensed and sent to the first reaction zone along with the other A part of this gas phase or the whole gas phase of this stage is subjected to condensation to obtain a vapor-liquid mixture and then sent to the first reaction zone, and the gas phase of the first distillation stage, containing th ammonia and carbon dioxide, is fed directly into the second reaction zone.
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    Total
    Table A
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    486 491.5 493 1997 2055.5 2051
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    同族专利:
    公开号 | 公开日
    NL8203258A|1983-05-16|
    AR230620A1|1984-05-31|
    IT1211125B|1989-09-29|
    IN157310B|1986-03-01|
    ES516549A0|1984-05-01|
    GB2107311A|1983-04-27|
    US4670588A|1987-06-02|
    GB2107311B|1986-01-29|
    ES8404676A1|1984-05-01|
    IT8124526D0|1981-10-16|
    DE3228594A1|1983-04-28|
    FR2514758A1|1983-04-22|
    CA1327606C|1994-03-08|
    JPS5883666A|1983-05-19|
    FR2514758B1|1985-07-05|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    CH498811A|1967-05-22|1970-11-15|Chemical Construction Corp|Process for the production of urea from ammonia and carbon dioxide|
    ES379855A1|1969-06-11|1973-02-16|Titsui Toatsu Chemicals Inc|Synthesis of urea|
    US4137262A|1969-10-16|1979-01-30|Snam Progetti S.P.A.|Process for the production of urea|
    US3984469A|1969-10-16|1976-10-05|Snam Progetti S.P.A.|Process for the production of urea|
    BE787832A|1971-09-02|1973-02-22|Stamicarbon|PROCESS FOR THE PREPARATION OF UREA|
    IT1068268B|1976-09-09|1985-03-21|Snam Progetti|PROCEDURE FOR THE PRODUCTION OF UREA AND PURIFICATION OF WATERS|
    BG35038A3|1977-05-05|1984-01-16|Montedison Spa,It|Method and installation for synthesis of urea|
    IT1174366B|1978-07-24|1987-07-01|Ortu Francesco|CARBAMATE DECOMPOSITOR FOR INDUSTRIAL PRODUCTION OF UREA|
    IT1141030B|1980-08-29|1986-10-01|Snam Progetti|PROCEDURE FOR THE PRODUCTION OF UREA|NL8400840A|1984-03-16|1985-10-16|Unie Van Kunstmestfab Bv|METHOD FOR THE PREPARATION OF UREA.|
    JPH082859B2|1987-02-24|1996-01-17|東洋エンジニアリング株式会社|Urea production method|
    IN169678B|1987-08-13|1991-11-30|Austral Pacific Fertilizers|
    EP0479103B1|1990-10-05|1996-03-06|Urea Casale S.A.|Process for the production of urea by steps with differentiated yields, and relevant implementations also on existing plants|
    US5276183A|1991-01-29|1994-01-04|Urea Casale S.A.|Process and plant for the production of urea|
    EP0544056B1|1991-11-14|1998-06-24|Urea Casale S.A.|Process for urea production with differentiated yield reaction spaces|
    US6274767B1|1992-11-19|2001-08-14|Urea Casale, S.A.|Process for the revamping of urea synthesis plants consisting of a stripper with ammonia|
    IT1274362B|1995-02-16|1997-07-17|Snam Progetti|HIGH YIELD PROCEDURE FOR THE SYNTHESIS OF UREA|
    US5767313A|1995-05-23|1998-06-16|Dsm N.V.|Method for the preparation of urea|
    US6231632B1|1999-05-25|2001-05-15|Engelhard Corporation|Urea processing agent|
    EP2644264A1|2012-03-28|2013-10-02|Aurotec GmbH|Pressure-controlled multi-reactor system|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    IT2452681A|IT1211125B|1981-10-16|1981-10-16|NITROGEN COMPOUNDS. PROCESS FOR THE PREPARATION OF|
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