Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/12—Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers

Definitions

• the subject of the invention is a process for the purification of acetylene.
• Acetylene is industrially stored under pressure in containers in the form of a solute in a solvent or in a mixture of solvents such as acetone or dimethylformamide (DMF), fixed by a porous material.
• the pressure in the container is between approximately 15.10 5 Pa and 20.10 5 Pa.
• acetylene When stored in solution in a solvent, acetylene contains at the outlet of the container, in addition to conventional impurities, oxygen, nitrogen, water or phosphine, a non-negligible amount of solvent in a content essentially dependent on storage pressure and temperature.
• acetylene When it comes to acetone, acetylene generally contains between 1% v / v and 10% v / v. Sometimes the solvent is entrained in liquid form with acetylene which hinders the user in the application in which he uses it.
• Another solution is to produce acetylene on the user's site to avoid this storage in solvent.
• This solution is not always industrially possible because the process by cracking hydrocarbons involves large investments which can only be made profitable by a high consumption of acetylene by the user. The same applies to the process by hydrolysis of calcium carbide.
• the subject of the invention is a process for the purification of acetylene stored under pressure in a container dissolved in a solvent, characterized in that it comprises: At least one step (a) of expansion of the acetylene at the outlet of the container, to produce a stream of acetylene gas comprising a non-zero quantity of liquid impurities,
• the acetylene obtained at the end of step (a) must be at a temperature sufficient to prevent its liquefaction and lower than the temperature Tdec, causing the decomposition of said gas. This temperature depends in particular on the working pressure of the gas.
• the process as defined above is generally implemented for a pressure of use of the acetylene gas greater than atmospheric pressure (approximately 10 5 Pa) and generally less than 10.10 5 Pa (10 bars) and more particularly less than or equal to 5.10 5 Pa (5 bars).
• atmospheric pressure approximately 10 5 Pa
• 10.10 5 Pa 10.10 5 Pa
• 5.10 5 Pa 5.10 5 Pa
• the process may include one or more separation steps.
• separation step (b) there is for example a step of condensing the solvent by cooling the gas stream from step (a) to a temperature lower than or equal to the liquefaction temperature of the solvent or of the mixture of solvents. .
• the stream of acetylene gas is more particularly made to circulate through a bed of activated carbon.
• the activated carbon used in the process which is the subject of the present invention has the following properties:
• the speed of circulation of the flow in the activated carbon bed is between 1 cm / s and 1 m / s and preferably between 5 cm / s and 50 cm / s.
• the acetylene leaving the container is expanded to a pressure less than or equal to 2.5 ⁇ 10 5 Pa (2.5 bars) and it is cooled to a temperature less than or equal to -15 ° C. .
• the solvent condensed during step (b) is recovered to be reused.
• it comprises a step of regenerating the bed of adsorbents.
• the regeneration of the adsorbent bed is carried out for example, with a hot gas such as nitrogen or acetylene, within pressure and temperature limits which do not induce acetylene instability. whether it is regenerating gas or whether it is the fraction of adsorbed gas.
• a hot gas such as nitrogen or acetylene
• the latter is preferably again subjected to steps (b) then (c) of the process as defined above.
• the invention finally relates to an acetylene production installation capable of implementing the method as defined above, comprising: an expansion means capable of delivering, at its outlet, acetylene at a pressure below 10.10 5 Pa (10 bars) and more particularly less than or equal to 5.10 5 Pa (5 bars), a means of exchanging frigories able to deliver downstream, a stream of gas cooled to a temperature between -70 ° C and 15 ° C, a means of purification by adsorption on a bed of particles and more particularly on a bed of activated carbon, capable of separating the residual liquid impurities from the cooled gas flow, a first connection pipe adapted so that the expanded gas s '' flows there from the outlet of said expansion means to the inlet of said refrigerant exchange means, and a second connecting pipe adapted so that the cooled gas flows there from the outlet of said refrigerant exchange means until the entry of said purification means by adsorption on a bed of particles.
• an expansion means capable of delivering, at its
• the refrigeration exchange means will consist of one or more exchangers connected to each other in series or in parallel, supplied with a refrigerant having a temperature lower than the gas flowing against the flow of the gas to be cooled.
• it comprises means for recovering the droplets of condensed solvent.
• a capacity containing packing rings provided with a drain in its lower part, to allow the evacuation of the condensate.
• the means for recovering droplets is integrated by means of exchange of fiigories.
• the means of separation by adsorption will consist of one or more beds of particles.
• the installation is insulated as a whole so as to limit the transfers of heat energy with the external environment with the exception of said first connecting pipe.
• Said first connecting line is long enough to prevent the acetylene from cooling downstream of the regulator
• the installation comprises a third non-insulated pipe adapted so that the hot gases serving for the regeneration of the adsorbent bed flow therein at the outlet of said bed and having a length large enough to not create hot spots in the residual acetylene .
• the process and the installation which are the subject of the present invention have the following advantages: They make it possible to easily make available to the user acetylene with a very low residual solvent content, often less than 500 ppm. When the process involves passing over a bed of adsorbents, they make it possible to obtain the gas with an impurity content of less than 100 ppb.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Analytical Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Water Supply & Treatment (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Separation Of Gases By Adsorption (AREA)
• Treatment Of Liquids With Adsorbents In General (AREA)

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Publications (2)

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• 2003
  • 2003-04-04 FR FR0304192A patent/FR2853313B1/fr not_active Expired - Fee Related
• 2004
  • 2004-03-17 JP JP2006505854A patent/JP2006522079A/ja active Pending
  • 2004-03-17 WO PCT/FR2004/050112 patent/WO2004089859A2/fr not_active Ceased
  • 2004-03-17 EP EP04721218A patent/EP1613575A2/fr not_active Withdrawn
• 2010
  • 2010-08-23 JP JP2010186242A patent/JP2011021017A/ja not_active Withdrawn

Non-Patent Citations (1)

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