DE1444963A1 - Process for removing carbonyl sulphide from gases and liquids - Google Patents

Description

"Process for removing carbonyl sulfide from gases and liquids" Priori ts June 30, 1959 / Netherlands / No. 240 771 If petroleum hydrocarbons, the If they contain sulfur, are split or reformed, hydrogen sulphide is formed and carbon sulfoxide, which are the main loci in the fractionation of the cleaved products remaining in the fraction are the atane, ethylene, propane, propylene, butane and butylene contains. The presence of these sulfur compounds increases these cleavage products smelly and corrosive and also dies if the products are processed further are, for example, on Solvents with @@ el, such as alcohols.

Even if you store split products that have already been completely removed from Are hydrogen sulfide free, the presence of small amounts of water leads to Formation of carbon dioxide and sulphurous water from the carbon sulphoxide by hydroxylysis, in that the sulfur water sotff oxidizes free sulfur with traces of Saueratofw ird, which is very difficult to remove.

The sulfur compounds mentioned also occur in industrial applications Gases such as water gas, coke oven gas, Cenerator-Sas and coal gas. The applicability of this Substance in the mentioned technical products is almost as undesirable as in the fission products.

Ea slad different useful ways of working for the removal of hydrogen sulfide has been applied. Bite bottles become hydrocarbons gowaschan with alkali hydroxide solution, and remove hydrogen sulphide.

Furthermore, the American patent 2 238 201 describes a Process, according to soft liquid hydrocarbons, the hydrogen sulfide and / or contain acidic Vorunrdiniguneen, are treated with water-soluble, basic reactive amines such as ethanolamine, isopropanolamine, polyethylene and polypropylene amines, Aminopopanediols and dieminopropanols. According to British patent publication 631 704 but amines cannot be used with success in those cases in which the hydrocarbons Carbon sulfoxide, carbon disulfide and / or Contain aldehydes, since these compounds with the amines to form stable, neutral nitrogen compounds react which do not have the opportunity to absorb possess any further amounts of hydrogen sulfide.

In addition, the original amines cannot be derived from them Reaction product can be restored by simply heating. According to the aforementioned British patent, however, atells an aqueous solution of diethanolamine Except for the insolfern because they are made for the removal of hydrogen sulfide Liquid hydrocarbons can be used, with any existing carbon dioxide is not bound. The diethanolamine solution, which contains hydrogen sulfide, can be regenerated by heating. The latter working method, however, asked the disadvantage that starting materials, which carbon sulfoxide in addition to hydrogen sulfide must be subjected to a separate aftertreatment, un the carbon sulfoxide to remove. According to British patent specification 481 235, such an aftertreatment is used carried out in a two-stage process in the case of coal hydrogen, in which A carbon dioxide which is free from hydrogen sulfide is, first of all is brought into contact with a practically anhydrous alcoholic solution of alkali hydroxide, whereupon the carbon sulfoxide formed from the hydrogen sulfide from the treated carbon Hydrogen with the help of an aqueous Alkelihydroxydlösung is revealed. A disadvantage of this approach is that that a large amount of alkali hydroxy is consumed, which is not a simple matter can be regenerated.

Contrary to what is stated in British patent specification 631 504 Regarding the inert nature of carbon sulfoxide in relation to the aqueous diethanolamine absorption y been told iot to have tore investigations (british patent 803 045) I was reluctant to use carbon sulfoxide when intensive milk conditions were used Removed from cheesecloth or liquids using an aqueous diethanolamine solution can be, and that also zip regenerates used diethanolamine solution obtained can be.

In this context, reference is also made to the American patent specification 2 726 992, which describes a method for removing carbon dioxide from normalerwieg gaseous petroleum hydrocarbons by intensively mixing this cace in liquid state with an aqueous diethanolaminluoun describes.

Contrary to expectations, it is now felt that the i .. 'application the intensive mixing enables the carbon sulfoxide to be completely or approximately Completely from gases and liquids, which at least partly not with water miscible are to be removed by applying an aqueous solution of dipropanolamines, and that the liquids consumed anialiendo in this treatment are simpler Way can be regenerated.

Lie invention also refers to a method of manufacture of funds and / or liquids that are completely or substantially completely have been freed from carbon dioxide and at least partially not with water mishcbar oind, by @ebanelen of alleys and / or liquids, which carbon sulfoxide and are at least partially not miscible with water with an aqueous solution Solution of an amino. After the process, the alley containing carbon sulfoxide will be or liquids at least 15 laps with an intensity not exceeding 70 ° the suspected amine phase is then separated off with the aqueous amine solution. Dna The process is characterized in that all amine liquids are a pure solution of one or several Dipropanolamines is used. The aqueous solution is one or less Dipropunolamine is hereinafter referred to as a dipropanolamine phase or merely as an amine term designated.

The sur use according to the previous conditions. Propanolamines suitable for the invention include the di-n-propanolamine [HN (CH2-CH2-CH2OH) 2] and the di-isopropanolamine [HN (CH2-CHOH-CH3) 2] and Camische these. Diisopro has proven to be particularly suitable proven.

Lo @s is to be found. because this compound has a greater absorption capacity in relation to the acidic compounds, such as hydrogen sulphide and carbon dioxide, has than diethanolanine, so that a smaller amount of the absorption liquid is required is.

A practical experiment showed that asked from a certain gas 1 mol of hydrogen sulfide and carbon dioxide can be absorbed by mol of diethanolamine can, while under otherwise yellow conditions only 3 moles of diisopropanolamine are required was.

For economic reasons, technical Diproapnaomian mixes are used in practice preferably used as a by-product in the manufacture of diethanolars can be obtained. these technical mixtures usually contain more than 90% by weight diisoporapnolamine nd 10 wt.% or less mono- and tripropanolamines. It's clear, that mixtures containing dinthanolamine can also be used.

When mixing the phase containing the carbon sulfoxide with the Dipropanaomainphase goes to a portion of the carbon sulfoxide in the last-named phase about, in weclher he presumably very quickly to hydrogen sulfide and carbon dioxide is hydrolyzed, which binds to amine with a basic reaction would. As a result, the shortage of carbon sulfoxide in the dipropanolamine phase becomes reduced and a further proportion of the hollow sulphoxide can be seen from the below treatment phase to transition into the dipropanolanine phase.

The time it takes for the carbon sulfoxide to transition from one phase into which the other is required depends mainly on the intensity of the touch between the two phases. Good contact is first and foremost cultivated by intimate mixing of the two phases; but also the relationship between the Renewing the two phases is an extremely important factor.

The more intense the mixing, the shorter the contact time be. With the setup that is currently available. it is, however, parking space Impossible to reduce the duration to less than every 15 declarations, as this is the application such a large mixing energy would mean that the present process For economic reasons, it is not suitable for use on a technical scale would come because the energy required would be so large and expensive.

When used in laboratory wet conditions, the present method has been found to be approximately 2 seconds can be carried out with a colloid mill. In these .. s case is however the mechanical power which is caused by the stirring device on the mixture of the two phases are transmitted nus, about 150 is / cbz of the Cet heu Vca technical and from an economic point of view, good results are usually obtained when the mixing takes place in such a way that the mechanical energy transmitted by the stirrer to the mixture of the two phases is 0.2 to 1.5 kw / cbm of the Gemsiches. In this case, the duration begins of the contact a usually not more than 30 minutes. When the phase to be treated a large henge contains carbon sulfoxide is the duration of contact between the in the. Phases are longer and / or intensive stirring is necessary the purification of a phase that contains less carbon oxide. Mixer in which the method can be carried out expediently, in particular for the treatment of liquids are, for example, propeller mixers and centrifugal mixers such as Trubomishcer and ultratrurax mixer. Apparatuses are preferably used for the treatment of gases used, by which the gas in the treatment liquid are finely distributed can. Very good results are obtained with coloons that have intermediate floors. can be seen, as well as with columns that are filled with packing material, such as Raschigringne are.

'..' "'-'-' When treating gases is the weight ratio used the dipropanolamine phase to the Cas phase to be treated is very dependent on the salary Hydrogen sulfide and carbon sulfoxide in these Gases, in practice this ratio is generally between 0, 1 and 2, c and usually between 2 and 10.

It is advantageous to use the dipropanolamine solution in the gases to be treated to bring into contact with increased pressure. In this case it enables the smaller Gas volumes a touch-up device with smaller dimensions. to use. Am second advantage is that the transition deo Sohwofelwascoratoffs and des Kohlonsulfoxyda in the anine phase through the increased partial pressure of these compounds is improved in the Gan.

When treating liquids, it is desirable that the volume ratio the diproapnolamine phase to the liquid phase to be treated is at least 0.1. In addition, it is being worked towards. daD. after the treatment a minimum period of time Liquid gel is dispersed. To achieve this, the volume ratio should be DipropanolaainphaBe to the liquid to be treated on during mixing a value not below 0.25 and preferably at 0.5, as below Under these conditions the Rpropanolmajknphaw is continuous and only small quantities the treated liquid can be carried along into the diproapnalmin phase.

The concentration of the aqueous Diproapnlaminlaminlpsung can. within further limits fluctuate. The amount of dipropanolamine in the charge is generally 10 to 60% by weight and expediently 15 to 30% by weight of the results of the present method can be further improved perdent by adding the aqueous dipropanolamine solution one or more compounds such as triethylene glycol or 2-methoxyethanol added, which the transition of carbon sulfoxide from the Cs or the liquid into this Favor solution.

The temperature at which daa. pre-existing procedures carried out is, is generally in the range from 0 to 70 ° and preferably from 10 to 15 °. If the from a. Splitting plant obtained xthane, propane or butane fraction If the method according to the invention is used, this is generally done at supra-atomic pressure. as in many cases these fractions are borne in the refinery exist in a liquid state and also further processed in this agate state will. For example, when treating liquid propane according to the invention, the is Printing usually extra. 25 at. Abs. and in the treatment of butane there is the pressure in general at ..

*. ' The procedure of the present invention is preferably described in carried out two stages close to the counter-current principle. Y.'onnd the previous years is carried out in mixers and settling vessels, one mixes the phase, which the Contains carbon sufloxdy and should be treated in the first Stucs with the liproapnolamine solution, which has already been partially used up. The two phases are placed in a sedimentation vessel separated and the phase to be treated is then ait fresher and / or regenerated Diporpanomain injection mixed to complete treatment. the partially used dipropanolamine solution, which is obtained in the last stage, can turn be mixed with untreated gas and / or untreated liquid.

The advance can of course also be carried out in more than two stages The individual treatments are carried out in a countercurrent torrent in a column be performed.

If the procedure is used in one stage, there is a risk of that the total amount of carbon oxides is transferred to the dipropanomain phase, or that not the Gemstemgen of the hydrogen sulfide bound by the Dipropanolacin is and in the phase to be treated backbone b bw. back into this. if If more than one stage can be used, the conditions described above are met the intimate cEschens compliance with certain volume ratios between the two Phases, the appropriately applied pressure and the Xoncement of the dipropanolamine solution generally maintained at every stage. At a Mehratufigan Arbaitawaiaa ka = as it is advantageous to use a temperature gradient, where the temperature as highest is in the stage in which the phase to be treated is for the first time with the Dipropanompsung is spoiled.

The completely or partially used solution. can in very can be easily regenerated before using them in the process can. The regeneration can take place, for example, by adding the amine solution a temperature from 70 to 130 °. delayed 100 to 120 °, heated, wordurh the components absorbed from the treated casings or the hydrolysis products formed by which steam escaping from the boiling solution is stripped off. These Treatment can be carried out very conveniently by indirect heating of the su regenerating solution bit low pressure steam, reducing the absorbed hydrogen sulfide. carbon dioxide, etc., are effectively expelled.

Surprisingly, it has been shown that with regeneration one used Diisoproaptnomainoläsur less stripping steam has to be used than with the regeneration of a corresponding used diethanolamine solution. The shit content of carbon sulfoyd in gases and / or liquids can be increased when using the method according to the invention can be reduced to less than 10% of the original salary, whereby the Hydrogen sulfide-sulfur content in this case is usually only 0.005 % or less.

The drawing shows an example of the treatment of a Liquid keti containing carbon sulfoxide according to the method according to the invention in a two-stage process and according to the countercurrent principle. The liquid to be treated enters the propeller through line 1. mixer 2 one, where ale with readyo partially previously used dipropanolaminlpsung, which is fed through line 3, stirred will. After vigorous stirring, the mixture is poured through line 4 into the settling tank 5 transferred, from where the consumed Dipropanolaminlosuhg through line 6 sur Regeneration system is derived. The liquid to be treated passes through. the line 7 in the propeller mixer 8, in which it is intimately mixed with fresh or regenerated dipropanolamine solution, which flows in through line 9. The chemical is transferred through the line 10 into the waste water tank 11, from where the completely or practically completely of carbon sulfoxide and hydrogen sulfide freed liquid is discharged through line 12. The teliwese used up Dipropanomainlösung is pumped through line 3 into the propeller mixer 3, where it is mixed with the liquid that has not yet been drilled. With treatment a gas containing carbon sulphoxide is passed through diesels into the propeller mixer an annular tube introduced, which is provided through openings and below of the propeller arranged it. In this case, the diproapnoma injection is guaranteed wisely supplied like this in the measurement by Bohandlung ainor Liquid represented @@@, with the exception that the dipropanomain solution at the bottom of the propeller mixer is initiated. The treatment of gases can, however, be a simple matter a Koloune, which nit intermediate floors, z. B. iöt with bell bottom, carried out will.

The invention is further elucidated with reference to the following pi example A gas consisting of t2 vol.% methane, 15 vol.% ethane + ethylene, 15% by volume propane + propylene, about 8% hydrogen and 0.05% by volume water sulfide and 50 parts to one million parts of carbon sulfoxide, was continuously introduced At the bottom of a column with a diameter of 1.8 m and a height of 12 m, eloha Contained 15 clock shelves. It was worked at 40 ° and a pressure of 15 at.

A 10% aqueous solution of technical diisopropanolamine, bestebehQ. us 94% by weight diisorpoapnomain, 4% by weight monopropanolamine and 2% by weight tripropanomain became continuous near the top of the column '-' '"." -... L ..'- "' e @ led. The relationship between the introduced gas @@@ nge and the dipropnaomain solution was (by volume) 900: 1. A total of 350 Tons of gas and 60 tons of diisopropanolamine solution in the course of 24 hours Column introduced. The gas discharged at the top of the column contained hydrogen sulfide less than 0.0015% by volume, while the carbon sulfoxide content is less than 0.5 part to a million parts. The above example is Kurdish in technical Na8 rod carried out and shows that practically the total amount of carbon sulfoxide namely 99 5, and approximately 97% of the hydrogen sulfide has been removed from the gas are.' When using an aqueous diethanolamine solution and. z Bonts constant Conditions were 80% of the carbon sulfoxide and 90% of the hydrogen sulfide the gas' away ...

....

The diisopropanol oil flowing out of the absorption tower, which 0.2 mol of hydrogen sulfide and carbon dioxide. contained per mole of diisopropanoimain, was continuously to the top of a Regeneration column passed. this column had a diameter of 0.9 m and a height of 15 m. It contained 16 clock floors. The floor temperature was kept by heating <.. '* with the correct defeat the Isorpopanllpsung and those from the treated Alleys and or The components that are eroded from the hydrolysis products are mixed with that from the boiling Solution escaping lapfmt is stripped off. With the amount of 3 kg stripping steam per Kilograms of the vapors circulating at the top of the column contained those at the bottom Falling diisopropane laminate solution 0.05 mol hydrogen sulphide and carbon dioxide per mole of diisopropanol.

This suggestion was traced back to the process after it had passed through Heat exchanger had cooled down.

The hydrogen sulfide concentration of the stripped gas, dae at the top of the regeneration column was such that it was without further Treatment can be processed in a sulfur recovery plant. regeneration a corresponding used diethanolamine solution would require an amount of 4k stripping steam 9 per kilogram of the gas expelled at the top of the column can be used.

Claims (1)

Claims: 1.) Process for removing carbonyl sulfide from Gases and liquids that are not or only partially miscible with water, by treating with an aqueous solution of a strong organic base, thereby characterized that the C05-containing case or liquids Bindceteno 15 seconds lanR at a temperature exceeding 70 degrees with an aqueous dipropanolamine solution brings into intimate contact and then the dipropanolamine phase enriched in COS separated and, if necessary, regenerated. ~ 2.) Vertabren according to claim 1, thereby Geeknnnzeichne that the Ceichteverheitnia between the dipropanominphase and a Subsequently treated Casphaae nd the gazon mixing process to a value two digits 0.1 and 20, preferably between 2 and 10, is held. 3.) Procedure according to claim 1, dadruch denoting that the volume ratio between the DipropacolaoinpRaae and a liquid Phzse to be treated during of the entire mixing process to at least 0.10 and preferably to about 0 will. 4.) Verharne after after 1 l to characterized in that the intimate Contact is ensured by the agitator of a mixer, which is on the A mixture of dipropanolsain phase and the phase to be treated is a mechanical force transfer, which is between 0.2 and 1t5 Kliowatt per cubic meter of the Gemsichen. : 5.) Proceed according to claims 1 to 4, characterized by t a the dipropanolanir content in the aqueous treatment location g is between 1 and 60% by weight. , 6.) Procedure hach Ansrpcuh 1 to 5, dadurhc marked, t that the aqueous diproanomain solution aulerdme still contains one or more compounds, which the passage of the carbonyl sulfide from the gas phase and / or flusat8ca Favor phase in this Meuxag. 7.) Method according to Ansrpuch 6, characterized in that the treatment solution Contains trinthylsengluycol. 8.) Proceed according to claim 6, since it is known that the Treatment solution contains 2-methoxyethanol. 9.) The method according to claim 1 to 8, d durch gekenzneihnt, da8 the applied temperature is between 155 and 50 °. 10.) Method according to claims 1 to 9, dadurhc gekenzneichn, ty daa Liquefied fission gauze can be treated with an aqueous dipropanolamine solution. 11.) Procedure according to claim 1 to 10, marked thereby that the treatment de & Ghseaunabs ... oderöerFlÜec'-ability with the aqueous dirpopanclamino solution in more than one stage and according to the countercurrent principle is carried out. 12.) according to claim 1 to H., characterized in that a technical da9 Dipropanolamine compound with a diisoprpanic clamine content of more than 90% by weight of mandrel will.