• 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:
    The present invention provides a method for separating fractions containing low and medium boiling point substances from a mixture of low, medium and high boiling point substances, wherein the medium boiling point component is stored in the vapor of the low boiling point substance and the medium boiling point component is It is directed to a separation process in which the mixture of the bottoms is treated with a low boiling point of vapor in the tower to be obtained at a temperature level.
    公开号:KR20000064483A
    申请号:KR1019980704679
    申请日:1996-12-20
    公开日:2000-11-06
    发明作者:오토 바트젠베르거
    申请人:스타르크, 카르크；바스프 악티엔게젤샤프트；
    IPC主号:
    专利说明:

    Method for separating heavy boiling point material from mixtures of low, medium and high boiling point materials
    The present invention relates to a method for separating heavy boiling point materials from a mixture of low, medium and high boiling point substances, which is separated into low and medium boiling point containing fractions and low and high boiling point containing fractions.
    A frequently encountered problem in the chemical industry is to have pure or only traces of low boiling point substances from a liquid multicomponent mixture consisting of a low boiling point (L), a medium boiling point (M) and a high boiling point (H) fraction. It is necessary to separate heavy boiling point materials.
    To this end, for example, Ullmann's Encyclopedia of Industrial Chemistry Vol. B3, see pages 4 to 46, known distillation methods can be used. A common feature of known distillation methods is that the high boiling point material is withdrawn from the bottom in pure form or with a trace of residual heavy boiling point material, the heavy boiling point component being at the top at a temperature determined mainly by the concentration of the high boiling point component or its boiling point. Withdraw. In addition, it is not possible to separate the mixture of low and high boiling point materials which do not contain the medium boiling point material and to co-separate the mixture of low and medium boiling point materials by the above known method. In many cases, however, co-separation would be desirable, especially if the low and high boiling point materials were placed in some additional common use (sale, recovery, disposal).
    Pages 4 to 48 of the aforementioned document describe the use of side columns to separate middle boiling materials from mixtures of low, medium and high boiling materials (L, M, H mixtures). Also in this case, the low and high boiling point materials are always separated. The same applies to the towers directly or indirectly bound described on pages 4 to 62 and pages 4 to 63 of the document. In any case, the separation of the heavy boiling point component by distillation from the high boiling point component is required. In each case, at least the same temperature as the boiling point of the medium boiling point component is required, and in extreme cases, it is close to the boiling point of the high boiling point component. Very high temperatures are required. This is especially true when the heavy boiling component must be completely separated from the high boiling component. Such high temperatures can lead to decomposition of related materials and generation of chemical conversions (polymerization reactions, etc.) even in the case of relatively thermally stable materials. For this reason, complex distillation techniques, such as gentle distillation (thin film evaporators, molecular jet distillation, etc.) performed under reduced pressure conditions, are often essential for this kind of separation process. This distillation technique has the disadvantage of extremely low throughput. This leads to expensive investment and product costs, which in itself means that advantageous distillation separation methods can be uneconomical to carry out.
    Special techniques are also known for separating liquid mixtures that are difficult to separate. This particular technique is only appropriate when it is more cost effective or when other conventional techniques have failed. This technique is often used for materials with limited ability to withstand thermal strains, i.e. boiling points above or near the decomposition temperature. Known methods for separating low volatile components from mixtures comprising immiscible components include carrier-gas distillation. The basis of the method is that, in a mixture of immiscible substances, each substance behaves as if it is free of other substances, that is, at a given temperature, each substance is at the same partial pressure as the vapor pressure of that substance, regardless of the composition of the mixture. Is to have. Thus, the total pressure of this mixture is equal to the sum of the vapor pressures of the individual components. Known examples are water / bromobenzene systems. Pure material boils at 100 ° C (water) and 156 ° C (bromobenzene), while the mixture boils at 95 ° C. Carrier gas distillation is relatively difficult to handle and relatively difficult to directly heat, because of the separation of relatively high boiling immiscible components (e.g. glycerol), the separation of substances that polymerize or decompose before reaching the boiling point (e.g. fatty acids). Particularly suitable for the separation of substances (eg terebin).
    The best known example of carrier gas distillation is steam distillation, ie distillation method in which the vapor is a carrier gas. This includes, for example, the removal of light hydrocarbons from absorbent oils in the refinery industry; Steam distillation of hydrocarbon fractions from coal distillation processes in the coal industry; Separation of terebin from resins in the rubber industry; And widely used in manufacturing organic chemistry. As described on pages 4-50 to 4-52 of the above-mentioned documents, steam distillation is a special form of azeotropic or extractive distillation. The technical effect of the method is based on the discovery that by adding a substitute (coating agent), far exceeding the azeotropic point results in the desired concentration being achieved even beyond the azeotropic point.
    All these techniques have the disadvantage of introducing an additive (coating agent) into the system to be distilled off and then separating it again from the system through further processing steps.
    A further known method of removing relatively high boiling materials from a mixture of certain materials is stripping. Stripping always produces only a very thin solution of the high boiling point component or the medium boiling point component in the stripping medium, which has the disadvantage of being difficult and expensive to separate. In general, the process is economical only when the product can be separated by phase separation, ie when the mixture of materials shows a difference in miscibility.
    It is therefore an object of the present invention to provide a simple and gentle method for separating middle boiling point or fraction comprising low and medium boiling point substances from a mixture comprising low, medium and high boiling point substances.
    The inventors have surprisingly found that the above-mentioned mixture in the column can be achieved by treating the above mentioned mixture with steam of low boiling point material at the bottom of the column.
    Thus, the present invention relates to fractions containing low and medium boiling point substances (L, M fraction) and homogeneous mixtures comprising low, medium and high boiling point substances (L, M, H mixtures) and low and high boiling point substances. A method for separating fractions (L, H fractions) comprising treating an L, M, H mixture with a low boiling point vapor in a column and separating the mixture into L, M fractions and L, H fractions. It provides a separation method. The L and M fractions can be recovered above the feed site of the mixture, and the L and H fractions accumulate in the vapor of the low boiling point material so that they can be obtained in the liquid phase.
    The mixture to be separated is usually passed directly to the top. Treatment of the mixture with steam of low boiling point material is preferably carried out in countercurrent, in particular by passing the vapor of low boiling point material to the bottom or by boiling it at the bottom by feeding the liquid low boiling point component. The low boiling point component supplied to the tower is usually the same as that present in the mixture.
    It has been found to be particularly advantageous to treat with low boiling point vapors in stripping towers. It may be a conventional plate column, for example a bubble-cap top or a sieve plate tower, or a conventional packing, for example Raschig rings, Pall rings, pedestals and the like can be provided, preferably in the range of 5 to 100 virtual plates. Depending on the separation process used, the number of plates may exceed 100.
    As a result of passing the vapor of the low boiling point material through the column bottom, the middle boiling component accumulates in the vapor of the low boiling point material. The L, M fraction is advantageously obtained above the vertical height of the feed plate. Preferably, the L and M fractions are withdrawn from the column top.
    Generally, the L and M fractions contain low to high boiling point components in large quantities. Therefore, in order to enrich the boiling point components in the L and M fractions, it is particularly advantageous to concentrate the L and M fractions. This can be done, for example, by passing L, M fractions through separate multi-columns, which serve as rectification towers, where the low boiling point components are separated to remove only the L, M fractions or pure heavy boiling point components rich in the medium boiling point components. Create
    It is particularly preferred that the rectification tower be provided as a separate distillation column or placed directly on the tower and treated with steam of the low boiling point material to distill the low boiling point component out of the column top. Concentrated L, M fractions or middle boiling components can be removed via lateral stream removal for the top conveying stream. It is particularly preferable to use partition walls that are essentially vertical in this regard. In this case, the mixture to be separated is usually fed to the center of the stripping-coupling column. At the vertical height of this feed point, the dividing wall is generally within the column in the range of 1 to 10, 1 to 5, in a theoretical manner, in such a way that the tower is vertically divided into two separate sections so that the supply is nearly centered on the dividing wall. Device. In this way, the fraction rich in the heavy boiling point component can be withdrawn from the opposite side of the feed site in the region of the dividing wall. The partition wall separates the withdrawal site from the supply site. There is a high boiling point material in the mixture only on the feed site side, but the heavy boiling point component is present on both sides of the dividing wall at the same concentration. The heavy boiling point-rich fraction is preferably withdrawn at approximately the vertical height of the feed site or, if appropriate, to some point below the point.
    As an alternative to an embodiment including a dividing wall, the side towers can be placed above the stripping-rectifying column in such a way that the gaseous or liquid phase of the stripping-refining tower communicates with the side towers above and below the feed site, This richer fraction is withdrawn through the side column. The side towers are arranged so that high boiling point components do not pass over to the side of the side towers. Means suitable for this are well known to those skilled in the art.
    If desired, a droplet separator (anti-fog device or other conventional device) can be installed on the feed plate or in the vapor outlet to prevent the high boiling components from being entrained by the droplets.
    The L, M fraction, enriched in the middle boiling point component from the above mentioned rectification column, can be separated or concentrated in further towers with rectification section and stripping section if necessary.
    A further advantageous embodiment of the novel process involves passing steam from a stripping tower or stripping distillation column back to the bottom of the treatment tower, if possible, after conventional compression, as steam of low boiling point components or low boiling point material. In this novel method, since low boiling point components or low boiling point vapors are generated during direct heating, steam compression is required only to overcome the pressure difference across the tower, so that energy consumption and energy input required for cooling can be extremely reduced at the same time. .
    The treatment tower and / or rectifier or distillation column may be operated continuously or batchwise under atmospheric pressure, reduced pressure or pressure. Against this background, of course, the operating conditions depend on the mixture to be separated and can be determined by a skilled person in the usual way. An important factor is the temperature of the vapor of the low boiling point material, which must be high enough to distill the L and M fractions and to obtain the L and H fractions at the bottom.
    The new method has the advantage of being convenient to carry out and can be carried out without the addition of any foreign material. The concentration of heavy boiling components is low over the entire process range. During the process, ie the residence time in the tower is relatively short. Simple process, low cost Moreover, the present process is almost infinite in its scale.
    This novel process allows very gentle separation of the L, M fraction or the middle boiling component from a mixture comprising low, medium and high boiling substances at the boiling point of the low boiling component. Thus, this process is particularly advantageous if it is necessary to separate the boiling point component as gently as possible from the L, M, H mixture which tends to decompose or polymerize heat. This process is particularly useful when the high boiling point components present in the crude mixture tend to undergo chemical reactions such as, for example, polymerization, in pure form or in concentrated form, or in high viscosity, solid precipitates, or relatively high concentrations. It is advantageous. Indeed, this novel process ensures evaporative removal of the high boiling point component dissolved in the low boiling point component. Thus, only solution is handled. In other words, problems such as viscosity and solids are eliminated.
    This new process is particularly suitable for obtaining heat sensitive products. Examples of such applications are:
    Obtaining an aqueous hydroxylamine solution from an aqueous solution of a hydroxylamine salt,
    Obtaining a mixture capable of polymerization, for example recovery of styrene from the mixture obtained in the production of styrene,
    Recovery of dichloroethane from a mixture obtained in the production of chlorinated hydrocarbons, for example in the production of dichloroethane,
    Recovery of carboxylic acids and aldehydes from acid stripping of cyclohexane oxidation by air or production of adipic acid,
    -Separation of organic acids and aldehydes such as acetic acid, acrylic acid, methacrolein or methacrylic acid from the product effluent, which will still contain high boiling point substances, organic compounds, salts (catalysts) and the like,
    Separation of amines from mixtures comprising ammonia and high boiling substances.
    This novel method will be described in more detail with reference to the schematic diagram shown in FIG. 1.
    1 shows a tower for separating L, M, H mixtures, including a stripping tower 1 with a rectifying tower 2 disposed thereon. The mixture to be separated is fed directly to the top of the stripping tower (1). A vapor L of low boiling point material is passed through the bottom of the stripping tower 1 in countercurrent to the mixture. L, M fractions are obtained which are essentially free of high boiling point materials in the column, while L, H fractions are withdrawn from the column bottoms. The L and M fractions are concentrated in the column. That is, the middle boiling point component is enriched. The concentrated L, M fractions are withdrawn to some extent on the feed site of the mixture to be separated. The low boiling point component is obtained from the top of the tower and can be concentrated and transferred for later use if necessary. Alternatively, the low boiling point component can be conveyed straight or after compression to the bottom of the stripping tower 1.
    The following examples illustrate the invention but are not limited thereto.
    <Example 1>
    Obtaining Hydroxylamine (HA) Aqueous Solution from Hydroxylamine (HA) / Ammonium Sulfate (AS) Solution Using Stripping Tower
    An aqueous solution containing 218 g HA per liter and 680 g AS per liter was fed to the top top tray of the stripping tower at a rate of 300 ml / h. The stripping tower is a glass product, 2 m high and 35 mm in diameter, and filled with a 3 mm glass Raschig ring to a vertical height of 1.8 m. 1000 mL / h of distilled water was fed to the bottom. The pressure in the tower was 40 kPa. The bottom temperature was 84 degreeC. 1000 mL / h of unsalted HA aqueous solution was distilled off from the top at a rate of 39.0 g HA / h, corresponding to 59.6% of the total HA on feed. 300 ml / h of ammonium sulfate solution having a HA content of 86.0 g of HA per liter was withdrawn from the bottom. This is equivalent to 39.4% of the total HA supply.
    The highest HA concentration in the column was 100 g / l. The amount of liquid in the column according to the specific fill amount was 20 to 225 ml. Thus, the residence time of the liquid in the column is only 1.5 to 10 minutes. Within these low concentrations and short times, the rate of degradation is low.
    Further experiments are listed in the table below.
    Separation of HA Solution from HA / AS Solution Feed HA content ml / h g / lH 2 O / -SteamPressureTower top temperature ℃HA amount from the top of the column g / ℓ (%)Amount of HA from the column bottom g / l (%) 318 2221156 *50.081.040.5 66.948.6 21.2 170 2221060 *70.090.522.8 65.645.2 17.2 370 2191475 yen100.4100.932.4 62.275.6 47.8 179 105.51530∧100.8100.69.0 70.529.0 27.6 245 220.01530∧100.8100.628.0 73.354.0 42.2 150 4990 yen100.8100.00.4 68.10.8 15.7 150 5.6990 yen100.899.90.6 73.00.4 5.6 119 20.41063∧101.5100.415.4 67.640.5 19.7 * The column bottom is heated by thermostat ∧ water is supplied as superheated steam for simultaneous bottom heating
    <Example 2>
    Separation of HA Solution from HA / Na 2 SO 4 Aqueous Solution Using Stripping Tower
    An aqueous solution from Example 3 containing 11 weight% HA and 23.6 weight% Na 2 SO 4 was fed to the top tray of the stripping tower at a rate of 978 g / h. The stripping tower was made of enamel and was filled with a 5 mm glass raschig ring, 2 m high and 50 m in diameter. The pressure in the tower was atmospheric pressure. The steam at 2.5 bar absolute was passed through to the bottom. The steam / feed ratio was 2.9: 1. 985 g / h of sodium sulfate solution having an HA content of 1.7 g of HA per liter were withdrawn from the bottom. This corresponds to 1% of the total amount of HA in the feed. 3593 g / h of an unsalted HA aqueous solution containing 36.8 g of HA per liter, corresponding to 99.2% of the total amount of HA in the feed, were distilled off from the tower.
    Further experiments are listed in the table below.
    Separation of HA Solution from HA Solution Feed HA content g / h g / ℓSteam / feed kg / kgPressureTower top temperature ℃HA amount from the top of the column g / ℓ (%)Amount of HA from the column bottom g / l (%) 945 1352.6200125.434.0 84.07.8 17 970 1362.7101106.335.5 96.23.3 2.5 980 802.8101107.02.1 95.50.45 5.7
    <Example 3>
    Obtaining HA Solution from HA / Sodium Sulfate Aqueous Solution Using a Stripping Distillation Column
    An aqueous solution containing 221 g of HA per liter and AS 540 g per liter was placed on the eleventh tray of a glass bubble-cap top 35 mm in diameter and 1.6 m in total length with 21 trays (lowest tray = tray 1). Feeding was at a rate of 202 mL / h. 1300 mL / h of steam (about 125 ° C.) was fed to the bottom. The pressure in the tower was 99 kPa. In the column top, 180 mL / h of substantial HA-free water (0.6 g of HA per liter) was withdrawn at a reflux ratio of 1: 3 (reflux: feed) at a tower top temperature of 99.8 ° C. An aqueous solution of HA (product solution) was withdrawn from the tray 12 through a lateral stream at a concentration of 44 g / l at a rate of 1180 ml / h. 400 ml / h of salt solution was withdrawn from the bottom.
    <Example 4>
    Obtaining HA Solution from HA Sodium Sulphate Aqueous Solution by Concentration by Side Draw-Out Using a Stripping Distillation Column
    An aqueous HA solution as in Example 3, containing 11% by weight of HA and 23.6% by weight of Na 2 SO 4 , was fed to an eleventh virtual plate of a glass bubble-cap top of 50 mm in diameter (30 virtual trays). Corresponding to the edition). 125 ° C. steam at 2.5 bar absolute was fed to the bottom. The pressure in the tower was 101 kPa. Substantial HA-free water (0.05 g HA per liter) was withdrawn from the top. An aqueous solution of unsalted HA (product solution) at a concentration of 8.3% by weight was recovered from tray 12 in a liquid form via a lateral stream. A salt solution with a 0.2 wt% residual HA content was withdrawn from the bottom.
    Example 5
    Concentration of Unsalted Hydroxylamine Solution by Distillation
    In a glass bubble-cap top having a diameter of 50 mm and a 30 bubble-cap tray, 1600 g / h of stable, unsalted hydroxylamine aqueous solution at a concentration of 8.3% by weight was fed on an eighth tray continuously. In addition, a small amount of stabilizer in the hydroxylamine solution was metered into the top tray of tray, tray number 30. The reflux ratio was set at 0.5. Water was distilled off from the top. The distillate still contained 0.07 wt% hydroxylamine residual. 240 mL / h of hydroxylamine solution at a concentration of 50% by weight was pumped out of the tower bottom.
    权利要求:
    Claims (12)
    [1" claim-type="Currently amended] A homogeneous mixture (L, M, H mixture) comprising low, medium and high boiling point materials in the column is treated with the vapor of the low boiling point material at the bottom and the mixture is separated into L, M fractions and L, H fractions. A process for separating fractions (L, M fractions) containing low and medium boiling point substances from a mixture of L, M, and H, comprising:
    [2" claim-type="Currently amended] The process of claim 1 wherein the L, M, H mixture is treated by passing a vapor of low boiling point material through the bottom of the column.
    [3" claim-type="Currently amended] The method according to claim 1 or 2, wherein the treatment is performed in countercurrent.
    [4" claim-type="Currently amended] The method according to any one of claims 1 to 3, wherein the tower used is a stripping tower.
    [5" claim-type="Currently amended] The process according to claim 1, wherein the L, M fraction is withdrawn from or above the vertical height of the feed tray, in particular from the top.
    [6" claim-type="Currently amended] The method according to any one of claims 1 to 5, wherein the L, M fractions are passed into a rectification column to separate low boiling point components to produce L, M fractions richer in heavy boiling materials in the rectification column.
    [7" claim-type="Currently amended] 7. The process according to claim 6, wherein the rectification column is disposed on the treatment tower, the low boiling point component is distilled off from the column top, and the L, M fractions enriched in the middle boiling point component are removed by lateral stream extraction.
    [8" claim-type="Currently amended] 8. The method of claim 7, wherein the treatment tower communicates with the bottom of the side tower and the rectification tower communicates with the tower top of the side tower.
    [9" claim-type="Currently amended] 8. The method of claim 7, wherein the dividing wall is essentially perpendicular to the stripping / rectification tower at the vertical height of the feed site of the L, M, H mixture.
    [10" claim-type="Currently amended] 10. The process according to any one of the preceding claims, wherein the middle boiling material of the L, M fractions is separated or concentrated in a further column having a rectifying section and a stripping section.
    [11" claim-type="Currently amended] The process according to claim 1, wherein the low boiling point component withdrawn from the column or rectifying column is at least partially conveyed to the column bottom after compression, if necessary.
    [12" claim-type="Currently amended] The method according to any one of claims 1 to 11, wherein the heavy boiling point product is sensitive to heat.
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    同族专利:
    公开号 | 公开日
    HRP960599B1|2001-12-31|
    KR20000064481A|2000-11-06|
    US5837107A|1998-11-17|
    KR100466771B1|2005-04-14|
    HRP960599A2|1998-02-28|
    JP4150075B2|2008-09-17|
    KR100479395B1|2005-05-16|
    US6254735B1|2001-07-03|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1995-12-20|Priority to DE19547758.8
    1995-12-20|Priority to DE19547758
    1996-07-29|Priority to US08/688,281
    1996-07-29|Priority to US8/688,281
    1996-07-29|Priority to US08/688,281
    1996-12-20|Priority to PCT/EP1996/005772
    1996-12-20|Application filed by 스타르크, 카르크, 바스프 악티엔게젤샤프트
    2000-11-06|Publication of KR20000064483A
    2005-04-14|Application granted
    2005-04-14|Publication of KR100466771B1
    优先权:
    申请号 | 申请日 | 专利标题
    DE19547758.8|1995-12-20|
    DE19547758|1995-12-20|
    US8/688,281|1996-07-29|
    US08/688,281|US5837107A|1995-12-20|1996-07-29|Process for production of aqueous solutions of free hydroxylamine|
    US08/688,281|1996-07-29|
    PCT/EP1996/005772|WO1997022550A1|1995-12-20|1996-12-20|Process for separating medium boiling substances from a mixture of low, medium and high boiling substances|
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