Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
  • F25J3/0238—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 2 carbon atoms or more
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/09—Purification; Separation; Use of additives by fractional condensation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
  • F25J3/0209—Natural gas or substitute natural gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/0204—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the feed stream
  • F25J3/0219—Refinery gas, cracking gas, coke oven gas, gaseous mixtures containing aliphatic unsaturated CnHm or gaseous mixtures of undefined nature
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J3/00—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification
  • F25J3/02—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream
  • F25J3/0228—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream
  • F25J3/0233—Processes or apparatus for separating the constituents of gaseous or liquefied gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream characterised by the separated product stream separation of CnHm with 1 carbon atom or more
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2200/00—Processes or apparatus using separation by rectification
  • F25J2200/02—Processes or apparatus using separation by rectification in a single pressure main column system
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2200/00—Processes or apparatus using separation by rectification
  • F25J2200/74—Refluxing the column with at least a part of the partially condensed overhead gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2205/00—Processes or apparatus using other separation and/or other processing means
  • F25J2205/02—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum
  • F25J2205/04—Processes or apparatus using other separation and/or other processing means using simple phase separation in a vessel or drum in the feed line, i.e. upstream of the fractionation step
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2205/00—Processes or apparatus using other separation and/or other processing means
  • F25J2205/82—Processes or apparatus using other separation and/or other processing means using a reactor with combustion or catalytic reaction
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2210/00—Processes characterised by the type or other details of the feed stream
  • F25J2210/12—Refinery or petrochemical off-gas
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2215/00—Processes characterised by the type or other details of the product stream
  • F25J2215/62—Ethane or ethylene
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2270/00—Refrigeration techniques used
  • F25J2270/12—External refrigeration with liquid vaporising loop
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2270/00—Refrigeration techniques used
  • F25J2270/18—External refrigeration with incorporated cascade loop
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2270/00—Refrigeration techniques used
  • F25J2270/66—Closed external refrigeration cycle with multi component refrigerant [MCR], e.g. mixture of hydrocarbons
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
  • F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
  • F25J2270/00—Refrigeration techniques used
  • F25J2270/90—External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
  • F25J2270/902—Details about the refrigeration cycle used, e.g. composition of refrigerant, arrangement of compressors or cascade, make up sources, use of reflux exchangers etc.

Definitions

• the present invention relates, in general and according to a first of its aspects, the gas industry, and in particular a process for recovering ethane contained in a pressurized gas comprising methane and C 2 and higher hydrocarbons, putting implementing a multi-component refrigeration cycle.
• multicomponent refrigeration cycle it should be understood that it is a refrigeration cycle using a refrigerant mixture composed of at least two refrigerants.
• the invention relates, according to its first aspect, to a process for recovering ethane contained in a pressurized gas comprising methane and C 2 and higher hydrocarbons, implementing a refrigerant cycle in which a first refrigerant fluid relatively less volatile is compressed, cooled and expanded to then serve to cool said pressurized gas to be separated or first separation products to a first relatively high temperature, and in which a second relatively more volatile refrigerant is compressed, cooled and expanded to then serve for cooling at least second separation products of said gas under pressure to a second relatively low temperature.
• Refrigeration methods of this type are well known to those skilled in the art and have been used for many years. These refrigeration methods have drawbacks in operating costs due to energy costs linked to the low thermodynamic efficiency of these refrigeration cycles. These known methods also have drawbacks in operating costs generated by maintenance difficulties or by the frequency of interventions, for example on compression installations, pumps, or even on measurement and control devices.
• a first object of the present invention is to propose a method, moreover in accordance with the generic definition given by the preamble above, which is essentially characterized in that the first and second refrigerants are used in mixture when compressed and cooled, in that this mixture is then subjected to separation into a first fraction essentially containing the first relatively less volatile fluid, and into a second fraction essentially containing the second relatively more volatile fluid, in that the first refrigerant is used in the form of the first fraction for cooling, at the first relatively high temperature, and in that the second refrigerant is used in the form of the second fraction for cooling at the second temperature relatively low.
• thermodynamics and also with regard to maintenance, by reducing the number of devices in the installation due to the combination of two refrigeration circuits in one.
• maintenance operations are simplified, the duration of the determination of the causes of failure of the installation is reduced, and consequently, a possible stoppage of production will be shorter than when using installations using a process. according to the prior art.
• the first fraction can be cooled in a first exchanger, expanded to give a first expanded fraction, then reheated in the first exchanger, to then be introduced at a low pressure stage of a compressor.
• the second fraction can be cooled in the first exchanger then in a second exchanger, expanded then reheated in the second exchanger, and mixed with the first expanded fraction.
• a third fraction can be taken from the first fraction after it has cooled in the first heat exchanger, and the third fraction can be expanded and reheated in the first exchanger to provide a relaxed fourth fraction and which can be introduced to a medium pressure stage of the compressor.
• a fifth gaseous fraction can be taken from fluids being compressed in the compressor (Kl) at an average pressure slightly higher than that of the fourth fraction expanded and reheated, then be cooled. and relaxed at the same pressure as said fourth fraction to be then mixed with the latter.
• the first and second refrigerants can be used in admixture with a third refrigerant.
• the refrigerants can be methane, ethylene and propane.
• the invention relates to a gas enriched in methane and a product enriched in ethane obtained by the present process as well as a product enriched in C 2 and higher hydrocarbons, obtained by the present process.
• the invention relates to an installation for recovering ethane contained in a pressurized gas comprising methane and C 2 and higher hydrocarbons, implementing, in particular, a multi-component refrigeration cycle , this installation using a refrigerant cycle and comprising means for compressing, cooling and expanding a first relatively less volatile refrigerant, means for cooling, by means of the first refrigerant, said pressurized gas to be separated or first separation products to a first relatively high temperature, and means for compressing, cooling and expanding a second relatively more volatile refrigerant, means for cooling, by means of the second refrigerant, at least second separation products of said gas under pressure to a second temperature relatively low, characterized in that the first and cond refrigerants are used in mixture when compressed and cooled, and in that this installation includes means for submitting this mixing with a separation into a first fraction essentially containing the first relatively less volatile fluid, and into a second fraction essentially containing the second relatively more volatile fluid, the first refriger
• FIG. 1 represents a functional block diagram of an installation in accordance with an embodiment of the prior art
• FIG. 2 represents a functional block diagram of an installation in accordance with a preferred embodiment of the invention.
• the installation shown is intended to treat a dry feed gas, in particular to isolate a fraction composed mainly of methane essentially free of C 2 and higher hydrocarbons on the one hand, and a fraction composed mainly of ethane and other C 2 and higher hydrocarbons essentially free of methane, on the other hand.
• This installation has three independent circuits.
• a first circuit corresponds to the path taken by a gas to be purified
• a second circuit corresponds to the cooling cycle of a refrigeration unit whose refrigerant is ethylene
• a third circuit corresponds to the cooling cycle of a refrigeration unit refrigeration whose refrigerant is propane.
• a feed gas 1, available at 15 ° C and 18 bar, with a flow rate of 3903 kmol / h is cooled in an El exchanger to provide a cooled gas 302 at minus 17.52 ° C and 17.8 bar.
• the latter is further cooled in a second exchanger E2, to provide a cooled fluid 303 at minus 30.00 ° C and 17.6 bar, partially condensed.
• Stream 1 is composed of 0.1% carbon dioxide, 24.3% methane, 74.4% ethane and 1.2% propane.
• the fluid 303 is then introduced into a balloon VI where it undergoes a separation of its liquid and gaseous constituents:
• the gas phase, flow 304, available with a flow rate of 2219 kmol / h is cooled to minus 60 ° C and partially condensed in a exchanger E3, for supply a fluid 305 at 17.4 bar.
• This fluid 305 feeds a distillation column T1 in its upper part.
• the liquid phase, flow 306, available with a flow rate of 1684 kmol / h is pumped by a PI pump, circulates in a pipe comprising a controlled valve 321, the opening of which depends on a liquid level controller present in the flask VI , to provide a flow 307 at minus 29.8 ° C and 19.6 bar. The latter is then introduced into a middle part of the distillation column T1.
• the Tl column produces at the top a vapor 308 at minus 65.79 ° C and 17.2 bar, available at a flow rate of 1358 kmol / h, which is cooled in an exchanger E4, to provide a partially condensed fluid 309 at minus 90 ° C and 17.0 bar.
• the latter is then separated in a V2 flask into a gaseous fraction 310 at a rate of 971 kmol / h which is composed of 0.1% carbon dioxide, 94.9% methane and 5.0% ethane, and in a liquid fraction 311 at a rate of 387 kmol / h which is composed of 0.4% carbon dioxide, 47.6% methane and 52.0% ethane, which is pumped by a P2 pump to a pipe 312.
• This pipe 312 comprises a controlled opening valve 322, the opening of which depends on the flow rate in this same pipe.
• the liquid fraction transported in line 312 is then introduced to the last stage of column Tl.
• the distillation column T1 has in its lower part several plates which are connected two by two by heating circuits, two of which are shown. These are circuits 315, 316 and 318, 319. Each of these heating circuits constitutes a lateral reboiler for circuit 315, 316, and a column bottom reboiler for circuit 318, 319.
• the fluid circulating in line 315, at a flow rate of 3000 kmol / h and at a temperature of minus 20.26 ° C is heated in one heat exchanger El, by heat exchange with the feed gas 1 to provide a fluid heated 316 to minus 16.61 ° C which is then introduced on a plate lower than the plate where the fluid 315 is drawn off.
• 315, 316 is carried out using a controlled opening valve 323, positioned on a bypass pipes of the circuit 315, 316 which does not pass into the exchanger El.
• the opening of this valve 323 is controlled by a temperature controller connected to line 302.
• 316 is heated in an E5 heat exchanger, by heat exchange with a refrigerant fluid consisting of propane, to provide a heated fluid 319 at minus 14.87 ° C.
• a refrigerant fluid consisting of propane
• the latter is introduced on a plate lower than the plate where the fluid 318 is drawn off.
• the regulation of the temperature of circulation of fluid in this circuit 318, 319 is carried out using a controlled opening valve 324, positioned on a branch line for the coolant transported in lines 220, 221, which does not pass through the exchanger E5.
• the opening of this valve 324 is controlled by a temperature controller connected to line 319.
• the residual liquid obtained at the bottom of the column Tl which is enriched in C 2 and higher hydrocarbons, is drawn off at a temperature of minus 14.87 ° C and a pressure of 17.4 bar at the rate of 2932 kmol / h by a line 314.
• This comprises a valve 325 whose opening is controlled by a liquid level controller at the bottom of the column Tl.
• the vaporization of the ethylene contained in the exchanger E4 makes it possible to cool the flow 8 coming from the head of the column Tl.
• the ethylene vapor thus obtained, flow 107 at minus 93 ° C and 1.83 bar, is directed to the low pressure stage of the compressor K1, passing through the suction balloon V3.
• the vaporization of the ethylene contained in the exchanger E3 makes it possible to cool the stream 4 coming from the tank VI.
• the ethylene vapor thus obtained, flow 103 at minus 62.83 ° C and 6.79 bar, is directed to the medium pressure stage of the compressor Kl, passing through the suction balloon V4.
• the compressed ethylene obtained at the outlet of Kl provides a fluid 112 at 17.75 ° C and 20.6 bar with a flow rate of 2570 kmol / h, which is cooled and condensed by successive passage through the exchanger E8 to give a fraction 118 at minus 7 ° C and 20.1 bar, then the exchanger E9 to give a fraction 119 at minus 30 ° C and 19.6 bar, then supplying the V5 flask with liquid ethylene.
• a flow of 4340 kmol / h of pressurized liquid propane 220 is withdrawn from a storage tank V6 at 42 °. C and 18 bar.
• This flow 220 is cooled in the exchanger E5 by heat exchange with the liquid circulating in the pipes 18, 19 to provide a cooled fluid 221 at 33.64 ° C and 17.5 bar.
• a pipe comprising a valve 24 makes it possible to regulate the exchanges of energy within E5.
• the 4340 kmol / h of the cooled fluid 221 are then separated into two flows:
• the opening of the valve 226 is controlled by a liquid level controller contained in the exchanger E8.
• the flow 201 supplies the exchanger E8 with propane refrigeration.
• a second stream 222 of 310 kmol / h which is cooled in the exchanger E7 to give the stream 223 at minus 25 ° C.
• Flow 223 is expanded by passing through a valve
• the propane flow 201 which is introduced into the exchanger E8 is partially vaporized to give a vapor phase 203 at a rate of 1387 kmol / h and a liquid phase 204 at a rate of 2643 kmol / h.
• This flow 204 is divided into two flows:
• the streams 225 and 224 are combined prior to their introduction into the exchanger E2 to give a stream 209.
• the vaporization of the propane in the exchanger E2 makes it possible to cool and partially condense the stream 2.
• the steam propane thus obtained, stream 210 at minus 33 ° C. and 1.48 bar is mixed with a gaseous stream 207 originating from the exchanger E9 to give a flow 211 which is first sent to a suction tank V7, then is directed to the low pressure stage of a compressor K2.
• the vaporization of the propane in the exchanger E9 makes it possible to cool and partially condense the flow 118.
• the steam propane thus obtained, flow 207 at less than 33 ° C. and 1.48 bar is mixed with the gas flow 210 from the exchanger E9 to give the flow 211 which is sent first to the suction tank V7, then is directed to the low pressure stage of the compressor K2.
• the vaporization of the propane in the exchanger E8 makes it possible to cool and partially condense the stream 112.
• the steam propane thus obtained, stream 203 at minus 10 ° C. and 3.46 bar is first sent to the suction flask V8, then is directed to the medium pressure stage of compressor K2.
• the compressor K2 supplies a flow 217 of compressed propane gas hot at 78.02 ° C and 18.6 bar, at a flow rate of 4340 kmol / h.
• This flow 217 is cooled in a first ElO exchanger to provide a cooled flow 218 at 52.36 ° C and 18.3 bar, then in a second Eli exchanger to provide a liquid flow 219 at 42 ° C and 18.0 bar. The latter is then stored in the balloon V6.
• the installation shown is intended to treat a dry feed gas, in particular to isolate a fraction thereof composed mainly of methane essentially free of C 2 and higher hydrocarbons on the one hand, and a fraction composed mainly of ethane and other C 2 and higher hydrocarbons essentially free of methane, on the other hand.
• This installation has two independent circuits.
• a first circuit corresponds to the path taken by a gas to be purified
• a second circuit corresponds to the cooling cycle of a refrigeration unit, the refrigerant of which is a mixture of at least three different products which can be in particular propane, ethylene, and methane.
• a feed gas 1, available at 15 ° C and 18 bar, with a flow rate of 3903 kmol / h is cooled to minus 60 ° C and 17.7 bar in an El exchanger, which is here a plate heat exchanger, to supply a cooled gas 303.
• El exchanger which is here a plate heat exchanger
• the latter feeds a distillation column Tl in its upper part.
• Stream 1 is composed of 0.1% carbon dioxide, 24.3% methane, 74.4% ethane and 1.2% propane.
• the Tl column produces at the head a vapor 308, at minus 66.21 ° C and 17.0 bar, at a flow rate of 1342 kmol / h, which is cooled in a exchanger E2, to supply a partially condensed fluid 309.
• the streams 308 and 309 are composed of 0.16% of carbon dioxide, 81.8% of methane and 18.0% of ethane.
• the flow 309 is then separated in a balloon V2 into a gaseous fraction 310, and into a liquid fraction 311.
• This liquid fraction 311 is transported by gravity in a pipe which includes a controlled opening valve 322 whose opening depends on the level of liquid in the flask VI.
• the liquid fraction 311 is then introduced to the last stage of the column T1.
• the gaseous fraction 310 from balloon V2 is composed of 0.1% carbon dioxide, 94.9% methane and 5.0% ethane. This enters an E2 heat exchanger at minus 90 ° C to provide a fraction heated 326 to minus 70 ° C., then passes successively through the heat exchanger El and through a controlled valve 317, the opening of which depends on the pressure in line 326. At the outlet of valve 317, the product is collected in a line distribution system 320 at 39 ° C and leaves the installation.
• the distillation column T1 has in its lower part several plates which are connected two by two by heating circuits, two of which are shown. These are circuits 315, 316 and 318, 319. Each of these heating circuits constitutes a lateral reboiler for circuit 315, 316, and a column bottom reboiler for circuit 318, 319.
• the fluid circulating in line 315 at a flow rate of 1000 kmol / h and a temperature of minus 40.7 ° C is heated in one heat exchanger El to provide a heated fluid 316 to minus 19.14 ° C. This is then introduced onto a plate lower than the plate where the fluid 315 is drawn off.
• the regulation of the temperature of circulation of fluid in this circuit 315, 316 is carried out using a valve with controlled opening. 323, positioned on a bypass pipes of circuit 15, 16 which does not pass through the exchanger El.
• the opening of this valve 323 is controlled by a temperature controller connected to the pipe 316 downstream of the mixing zone of the fluids circulating in line 316 and the bypass line comprising valve 323.
• the fluid circulating in line 318 at a flow rate of 3790 kmol / h and a temperature of minus 17.36 ° C is heated in the heat exchanger El to provide a heated fluid 319 at minus 14.94 ° vs.
• the latter is then introduced onto a plate lower than the plate where the fluid 318 is drawn off.
• the regulation of the temperature of circulation of fluid in this circuit 318, 319 is carried out using a controlled opening valve 324 , positioned on a bypass pipes of circuit 315, 316 which does not pass through the exchanger El.
• the opening of this valve 324 is controlled by a temperature controller connected to the pipe 316 downstream of the mixing zone of the fluids circulating in the pipe 319 and the bypass line comprising the valve 324.
• the residual liquid obtained at the bottom of the column Tl which is enriched with C 2 and higher hydrocarbons, is withdrawn by a pipe 314 which includes a valve 325 whose opening is controlled by a liquid level controller at the bottom column Tl.
• This liquid available at minus 14.94 ° C and 17.4 bar, is composed of 0.1% carbon dioxide, 1% methane, 97.4% ethane and 1.5% propane.
• a refrigerant mixture 13 composed of 5% methane 12, 25% ethylene 3, and 70% propane 2, at a temperature of 42 ° C and a pressure of 27.79 bar, and whose flow rate is 3970 kmol / h, is separated in a V2 flask into a first fraction 4 containing essentially the first less volatile fluid 2 and in a second fraction 5 essentially containing the second more volatile fluid 3 and the third more volatile fluid 12.
• the stream 14 is then cooled in an exchanger E2 to give a stream 15 available at minus 90 ° C and 27.1 bar.
• This flow 15 is expanded in a valve 16 to provide a flow 17 at a pressure of 2.3 bar and at a temperature of minus 96 ° C.
• the opening of valve 16 is regulated by a temperature controller in line 310.
• the flow 17 is heated in the exchanger E2 and is partially vaporized in order to meet the refrigeration needs of the exchanger E2, to supply the flow 18 at a temperature of minus 67.9 ° C and a pressure of 2.2 bar at the outlet of the exchanger.
• Flow 4 which constitutes the liquid phase of the separating flask V2, is composed of 2.2% methane, 18.3% ethylene and 79.5% propane, the flow rate of which is 2501 kmol / h, is cooled in one heat exchanger El to give a flow 19 available at minus 60 ° C.
• the stream 19 is then separated into two streams:
• a flow 8 the flow rate of which is 1000 kmol / h, is expanded to 8.1 bar by passing through a valve 20, to give a flow 21.
• the latter is vaporized and reheated in the exchanger El to give a flow 9 at a temperature of 38.5 ° C and a pressure of 7.8 bar.
• the latter available at a temperature of minus 64, 93 ° C and a pressure of 2.2 bar, composed of 6.0% methane, 27.2% ethylene and 66.8% propane, is vaporized and heated in the El exchanger to provide a flow 7 available at 38.5 ° C and 1.9 bar.
• the flow 7 is directed to the low pressure stage of a compressor K1, passing through a suction balloon V3.
• the flow 9 flows through a suction balloon V4, then is mixed with the flow 25 to provide a flow 10 at a flow rate of 3970 kmol / h, at 41.01 ° C and 7.7 bar. This latter flow 10 is introduced at a medium pressure stage of the compressor K1.
• the method according to the invention allows a power gain of 9.4%
• the surface area of the cooling water exchangers of the process according to the invention is 29% less than that of the conventional process.
• the water consumption is 5.4% lower for the process of the invention.
• the process according to the invention uses a larger total exchange area of 21% compared to the known process. However, the cost of these exchangers is lower.
• the method of the invention comprises only 11 pieces of equipment instead of 24 for the known method.
• the new process has 8 control chains instead of 13 for the conventional process.
• the invention therefore presents an advantage for limiting energy expenditure during the production of purified gases. This object is achieved while allowing a high selectivity of separation of methane and other constituents during the implementation of the process.
• results obtained by the invention provide significant advantages constituted by a substantial simplification and economy in the production and technology of the equipment and methods of their implementation as well as in the quality of the products obtained by these methods.

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• 2001
  • 2001-02-26 FR FR0102582A patent/FR2821351B1/fr not_active Expired - Fee Related
• 2002
  • 2002-02-04 CN CNA028055640A patent/CN1509262A/zh active Pending
  • 2002-02-04 WO PCT/FR2002/000419 patent/WO2002068366A1/fr not_active Application Discontinuation
  • 2002-02-04 BR BR0207301-3A patent/BR0207301A/pt active Pending
  • 2002-02-04 US US10/469,090 patent/US20040069015A1/en not_active Abandoned
  • 2002-02-04 EP EP02701402A patent/EP1363867A1/fr not_active Withdrawn
  • 2002-02-04 CA CA002438872A patent/CA2438872A1/fr not_active Abandoned
  • 2002-02-22 AR ARP020100622A patent/AR032835A1/es not_active Application Discontinuation
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