• 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 relates to a unit (1) for recovering hydrogen chloride from a hydrochloric acid, aqueous liquid (31) contaminated with low or non-volatile impurities, comprising an evaporation unit (30) for forming a vapor (32) containing hydrogen chloride and one with the heavy or non-volatile impurities contaminated liquid concentrate (33) from the liquid (31), a first distillation unit (10) for separating the steam containing hydrogen chloride (32) into a first overhead product (12) and a first bottom product (13), and a second distillation unit (20) for separating a hydrogen chloride-containing aqueous fluid (21) into a second top product (22) and a second bottom product (23), one of these two distillation units being designed to be able to carry out a distillation therein above ambient pressure and the other of these two Distillation units is designed to be a distillation to be able to carry it out below the ambient pressure, and the first distillation unit (10) is connected in a fluid-conducting manner to the second distillation unit (20) in such a way that at least a part of the first bottom product (13) is able to form at least a part of the hydrogen chloride-containing aqueous fluid (21) .
    公开号:AT16772U2
    申请号:TGM50066/2020U
    申请日:2020-03-24
    公开日:2020-06-15
    发明作者:
    申请人:Sgl Carbon Se；
    IPC主号:
    专利说明:

    description
    HCL RECOVERY UNIT
    The present invention relates to a unit and a method for the recovery of hydrogen chloride (HCl) from hydrochloric acids, contaminated with non-volatile or non-volatile impurities, aqueous liquids, which occur in particular in the production of aluminum oxide as a by-product stream. DESCRIPTION
    [0002] Aluminum oxide can be obtained from bauxite. The Bayer process is predominantly used for this, whereby bauxite is digested under pressure with sodium hydroxide (e.g. 7 bar, 180 ° C), insoluble impurities are separated off and aluminum hydroxide is precipitated from the supernatant. The aluminum hydroxide is converted to aluminum oxide by calcination. This process requires a lot of energy. When this process was developed, ores with high aluminum contents were available in sufficient quantities.
    The remaining aluminum-containing ores sometimes have a significantly lower aluminum content. Alternative, efficient processes are being developed with which aluminum oxide can be extracted from the remaining ores in the desired purity.
    Processes which start from kaolin are described in AU 2014 253 487 A1 and AU 2018 101 228 A4. Hydrogen chloride in the form of gas and in the form of hydrochloric acid is used in different process steps. The aluminum is extracted from the crushed and calcined ore with hydrochloric acid. Other metals contained in the ore also go into solution. Insoluble components such as SiO>, are then separated from the solution by solid-liquid separation. The supernatant obtained contains, in addition to large amounts of dissolved aluminum, also other dissolved metals, e.g. Traces of iron, magnesium, manganese, calcium, sodium and / or potassium. The aluminum is separated from the other dissolved metals by increasing the HCI content of the supernatant, which is in any case hydrochloric acid (e.g. by introducing HCI gas), as a result of which aluminum chloride hexahydrate fails. The aluminum chloride hexahydrate is separated from the supernatant of the aluminum chloride hexahydrate precipitation and converted to alpha-aluminum oxide by heating up to 1300 ° C., the hydrogen chloride-containing roasting gas being driven off.
    In such, HCI-driven processes for the extraction of aluminum oxide, HCI-rich by-products or by-product streams are produced. These include the supernatant of the aluminum chloride hexahydrate precipitation, which has a high HCl concentration and also contains aluminum and other metals which have not precipitated. In addition, the roasting gas containing hydrogen chloride is produced. It is very difficult to handle because it is very hot and highly corrosive. No fully satisfactory proposal has yet been made for handling these HCI-rich by-product streams.
    The present invention has for its object to provide a unit for the described, HClI-driven processes for aluminum oxide extraction, with the help of which a high purity of the aluminum oxide is guaranteed and at the same time a particularly efficient process control is achieved. In particular, the unit, in cooperation with the HCI-driven process, should effectively counteract the carryover of metals contained in the ore into the aluminum oxide. This should essentially be achieved without the supply of fresh HCI from the outside and with the lowest possible disposal costs for by-products contaminated with hydrogen chloride.
    [0007] This object is achieved by a unit for the recovery of hydrogen chloride
    from a hydrochloric acid, contaminated with heavy or non-volatile impurities
    th, aqueous liquid, comprising
    an evaporation unit for the formation of a vapor containing hydrogen chloride and a liquid concentrate from the liquid which is contaminated with the non-volatile or non-volatile impurities,
    a first distillation unit for separating the steam containing hydrogen chloride into a first top product and a first bottom product, and
    a second distillation unit for separating an aqueous fluid containing hydrogen chloride into a second top product and a second bottom product,
    in which
    one of these two distillation units is designed to be able to carry out a distillation above the ambient pressure and the other of these two distillation units is designed to be able to carry out a distillation therein below the ambient pressure, and
    - The first distillation unit is fluidly connected to the second distillation unit so that at least a part of the first bottom product is able to form at least a part of the hydrogen chloride-containing aqueous fluid.
    The top product of the distillation unit, which is designed for distillation above ambient pressure, is very rich in hydrogen chloride and contains e.g. at least 90% by weight hydrogen chloride. It is (quasi) free of non-volatile or non-volatile contaminants, e.g. Metals. This overhead product can thus preferably be used to precipitate an aluminum chloride hexahydrate from an aluminum-containing solution, e.g. from the supernatant obtained in the process of AU 2018 101 228 A4 after the separation of SiO. The overhead product replaces fresh HCl, which would otherwise have to be added. In certain units according to the invention, a drop separation device is integrated, through which the top product of the distillation unit, which is designed for distillation above ambient pressure, is passed. This makes it possible to achieve a total content of metallic impurities below 10 ppmw.
    As hydrochloric acid, contaminated with low or non-volatile impurities, an aqueous liquid can e.g. each supernatant is used to precipitate aluminum chloride hexahydrate by increasing the HCl concentration, e.g. the supernatant of the aluminum chloride hexahydrate precipitation in HClI-driven processes for the extraction of aluminum oxide. The non-volatile or non-volatile impurities then include the non-precipitated aluminum and the non-precipitated other metals. However, the invented unit can also be used to treat any other aqueous hydrochloric acid contaminated with non-volatile or non-volatile impurities. E.g. any hydrochloric acid, aqueous liquid which has been brought into contact with an ore in an acidic digestion.
    Surprisingly, it was found that the first and / or second bottom product, which collect in the distillation units below during operation of the unit according to the invention, each represent ideal absorption liquids for taking up further hydrogen chloride. For example, in the process of AU 2018 101 228 A4 roasted gases containing hydrogen chloride are produced, from which hydrogen chloride gas can be at least partially separated by absorption in at least one of the bottom products. Thus, the unit according to the invention is equally suitable for the treatment of hydrochloric acids, aqueous liquids contaminated with nonvolatile or non-volatile impurities and for the treatment of gases contaminated with hydrogen chloride.
    The invention can be used universally in conjunction with any process in which HCl and / or hydrochloric acid are required and hydrochloric acid, aqueous by-products containing heavy or non-volatile impurities are obtained.
    The present invention is not limited in terms of the type of evaporation unit. The vaporization units which are known to the person skilled in the art and are sufficiently corrosion-resistant to hydrogen chloride and hydrochloric acid can be used to form the hydrogen chloride-containing vapor from the aqueous liquid. Good results are achieved in particular if the hydrogen chloride-containing vapor is formed from the aqueous liquid in an evaporation unit which has at least one evaporator selected from natural circulation evaporators, forced circulation evaporators, kettle evaporators, falling film evaporators.
    steamers and any combination of the above evaporators. Forced circulation evaporators are particularly preferred. Little crystallization (fouling) occurs in it. The liquid concentrate that forms can then be further concentrated, so that a particularly small volume, to be treated, with the low or non-volatile impurities, e.g. Metals, contaminated liquid. If the evaporation unit comprises a forced circulation evaporator, this can also be followed by a flash evaporator.
    Although it is fundamentally possible in the context of the present invention that the evaporation unit is designed in several stages, single-stage evaporation units are particularly preferred.
    In contrast to single-stage, multi-stage in connection with the evaporation unit means that there are at least one upstream and one downstream evaporator stage. A part of the steam containing hydrogen chloride is formed in the upstream evaporator stage. This part of the steam containing hydrogen chloride provides at least part of the thermal energy for the operation of the downstream evaporator stage. In the downstream evaporator stage, part of the liquid is evaporated that has not yet evaporated in the first evaporator stage. The downstream evaporator stage is generally operated at a lower pressure and / or at a lower temperature than the upstream evaporator stage.
    The one-stage evaporation unit is preferred because of the simplicity of the apparatus. In addition, the invention realizes the energy recovery inherent in a two-stage evaporation even with a one-stage evaporation unit. This is because the steam containing hydrogen chloride helps to heat the bottom of the first distillation unit.
    In order to protect the evaporation unit from a corrosive attack by the hydrochloric acid, aqueous liquid, inner surfaces of the evaporation unit that come into contact with the liquid and / or with the hydrogen chloride-containing vapor are at least partially preferably made of graphite, silicon carbide, carbon fiber-containing composite materials, fluorinated polymers, Enamel, glass, glass fiber reinforced plastic (GRP) and / or rubberized steels are formed, with graphite, silicon carbide and / or polytetrafluoroethylene being particularly preferred. This increases the longevity of the evaporation unit. The graphite is preferably impregnated with resin such as phenolic resin. Polytetrafluoroethylene can be applied to inner surfaces as a coating or as a film.
    During operation of the evaporation unit, the liquid is concentrated to the liquid concentrate. The evaporation unit preferably has a liquid outlet for removing the liquid concentrate which is formed. The term liquid concentrate means that the non-volatile or non-volatile impurities are present in a higher concentration (i.e. with a higher mass fraction) than in the liquid. The liquid concentrate can also contain solids, e.g. dispersed metal salts. The removal of the liquid concentrate that is formed means that non-volatile or non-volatile substances, e.g. metal ions or dispersed metal salts dissolved therein are not led into one of the distillation units via the liquid discharge. Ultimately, this enables a high-purity HCI gas to be generated.
    [0018] The evaporation unit can have a phase separator. The vapor generated during evaporation flows into the phase separator. Liquid collects in the phase separator, which is entrained by the steam in the form of droplets. The phase separator preferably has a return line in order to feed the collecting liquid again to the evaporation. This has the advantage that even less difficult or non-volatile substances, e.g. dissolved metal ions are carried into the first distillation unit, in the bottom of which they would otherwise collect. This makes the unit according to the invention even more efficient, since no or only a very small proportion of bottom products has to be removed in order to prevent undesired accumulation of non-volatile or non-volatile substances, e.g. counteract dissolved metal ions in the bottom products.
    The evaporation unit is fluidly connected to the first distillation unit according to the invention such that at least a portion of the steam containing hydrogen chloride, preferably all of the steam containing hydrogen chloride, can get into the first distillation unit. The fluid-conducting connection of the two units can be provided, for example, by a line which leads from the evaporation unit to the first distillation unit. A droplet separating device can be integrated in the fluid-conducting connection. Droplets are separated in the droplet separator, which otherwise would contain certain quantities of non-volatile or non-volatile substances, e.g. dissolved metal ions, would carry into the first distillation unit. A part of the steam containing hydrogen chloride can also be branched off.
    The fluid-conducting connection of the evaporation unit to the first distillation unit preferably opens into a lower region of the first distillation unit. It was shown that heat that was used for evaporation in the evaporation unit can be introduced with the steam into the first distillation unit and used to heat the sump if the fluid-conducting connection opens into the lower region of the first distillation unit. Surprisingly, this saves a large part of the energy that would otherwise have to be supplied from the outside to heat the sump of the first distillation unit.
    [0021] The unit according to the invention has a first distillation unit. Any distillation unit with which the hydrogen chloride-containing vapor can be separated into the first top product and the first bottom product is suitable as the first distillation unit. The first top product is a lower boiling gaseous fraction and the first bottom product is a higher boiling liquid fraction. The first distillation unit is preferably a first column.
    [0022] The unit according to the invention also has a second distillation unit. Any distillation unit with which the aqueous fluid containing hydrogen chloride can be separated into the second top product and the second bottom product is suitable as a second distillation unit. The second top product is a lower boiling gaseous fraction and the second bottom product is a higher boiling liquid fraction. The second distillation unit is preferably a second column.
    The person skilled in the art knows adequately corrosion-resistant internals, packing and linings against the influence of hydrochloric acid and hydrogen chloride gases and equips the first and second distillation units or columns accordingly, e.g. by lining with PTFE.
    According to the invention, the first distillation unit is connected in a fluid-conducting manner to the second distillation unit in such a way that at least part of the first bottom product is able to form at least part of the hydrogen chloride-containing aqueous fluid. The fluid-conducting connection of the two units can be provided, for example, by a line which leads from the bottom of the first distillation unit to the second distillation unit. Then the first bottom product forms the hydrogen chloride-containing aqueous fluid. A tank is preferably integrated in the line, a section of the line leading from a lower region of the tank to the second distillation unit. This ensures that a constant stream of hydrogen chloride-containing aqueous fluid can be fed to the second distillation unit, even if fluctuations occur in upstream process steps. However, the indication that at least a part of the first bottom product is able to form at least a part of the hydrogen chloride-containing aqueous fluid expresses that the fluid-conducting connection e.g. may have a branch and a branchable part of the first bottom product is not fed to the second distillation unit, but is discharged from the unit, e.g. to remove heavy or non-volatile impurities (entrained in the evaporation unit during evaporation). Alternatively or additionally, a further fluid can be supplied to the fluid-conducting connection, e.g. via a feed line opening into the line or the tank, so that a further part which is not formed from the first bottom product
    of the hydrogen chloride-containing aqueous fluid to a feedable liquid.
    [0025] According to the invention, the two distillation units are designed differently. One of the two distillation units is designed to be able to carry out a distillation therein above the ambient pressure and the other of these two distillation units is designed to be able to carry out a distillation therein below the ambient pressure.
    Distillation units such as e.g. Columns that are designed for operation above ambient pressure must be sealed against the outflow of fluid from the inside to the outside. In addition, their walls must be designed in such a way that they can absorb the tensile loads associated with overpressure without being deformed.
    In contrast, distillation units, e.g. Columns which are designed for operation below the ambient pressure must be sealed against the inflow of ambient air into the column. In addition, their walls must be designed in such a way that they can withstand the pressure load associated with the vacuum without deformation.
    The first distillation unit can be designed to separate a fluid which can be recycled into the distillation unit and the steam containing hydrogen chloride into the first top product and the first bottom product. In addition to the inlet for the hydrogen chloride-containing steam, it then has an additional inlet for the recyclable fluid, which is preferably arranged above the inlet for the hydrogen chloride-containing steam. In general, the second distillation unit is then fluidly connected to the first distillation unit in such a way that at least a part of the second bottom product is able to form at least a part of the recyclable aqueous fluid. The fluid-conducting connection of the two units can be provided, for example, by a line which leads from the bottom of the second distillation unit to the first distillation unit. Then the second bottom product forms the recyclable aqueous fluid. A tank is preferably integrated in the line, a section of the line leading from a lower region of the tank to the first distillation unit. This ensures that a constant flow of the aqueous fluid can be fed to the first distillation unit, even if fluctuations occur in the second distillation unit. However, the indication that at least a part of the second bottom product is able to form at least a part of the recyclable aqueous fluid expresses that the fluid-conducting connection e.g. can have a branch and a branchable part of the second bottom product is not fed to the first distillation unit, but is removed from the unit according to the invention. Alternatively or additionally, a further fluid can be supplied to the fluid-conducting connection, e.g. via a feed line opening into the line or the tank, so that a further part of the recyclable aqueous fluid, which is not formed from the second bottom product, is due to a feedable liquid.
    According to a specific embodiment of the units for the recovery of hydrogen chloride according to the invention, a hydrochloric acid removal unit can be provided, through which part of one of the bottom products or the steam containing hydrogen chloride can be introduced. Suitable hydrochloric acid extraction units are the branches mentioned here or the tanks. The extracted hydrochloric acid can be recycled in an HCI-driven process for the extraction of aluminum oxide and there e.g. be used to extract aluminum from the crushed and caleined ore.
    However, it is particularly preferred according to the invention to obtain all hydrochloric acid and all the hydrogen chloride gas which is to be recycled in the HClI-driven process for the production of aluminum oxide from the overhead product of the distillation unit designed for operation above ambient pressure, if necessary with the addition of Water to form hydrochloric acid. This ensures that virtually no non-volatile or non-volatile impurities are recycled into the aluminum oxide production. This ensures a particularly high purity of the aluminum oxide.
    It was already emphasized above that the first and / or the second bottom product, which collects in the distillation units below during operation of the unit according to the invention,
    represent ideal absorption liquids for the absorption of further hydrogen chloride. Based on this, a preferred embodiment of the unit according to the invention is proposed, which is additionally suitable for the recovery of hydrogen chloride from gas containing hydrogen chloride, comprising an absorption unit for absorbing hydrogen chloride gas from the gas into an absorption medium while obtaining a hydrogen chloride-enriched absorption medium and a hydrogen chloride-depleted gas. The gas containing hydrogen chloride may e.g. is a roasting gas generated in HCI-driven processes for the extraction of aluminum oxide. At least one of the distillation units is preferably connected to the absorption unit in a fluid-conducting manner in such a way that at least a part of at least one of the two bottom products in the absorption unit can serve as the absorption medium.
    As an absorption unit, any unit comes into consideration that enables measurable absorption of hydrogen chloride in an absorption liquid. This is always the case when there is only a little intensive contact between the hydrogen chloride gas and one of the bottom products. As an absorption unit, e.g. also serve as a quencher. Preferred absorption units have internals and / or packings which bring about intimate mass transfer contact between gas and liquid.
    The absorption unit can be an absorption unit with countercurrent flow of roasting gas and absorbent or with cocurrent flow of roast gas and absorption medium.
    Another aspect of the invention thus relates to the use of hydrochloric acid for the absorption of hydrogen chloride from a hydrogen chloride-containing gas formed during thermal decomposition. The hydrochloric acid used for absorption preferably contains at least 21% by weight, in particular at least 22% by weight, of hydrogen chloride. This refers to the hydrochloric acid present before absorption. Thermal decomposition includes e.g. thermal decomposition of a metal chloride, e.g. in the presence of water, preferably a thermal decomposition of a metal chloride hydrate, in particular the thermal decomposition of aluminum chloride hexahydrate. The protons required for the complete conversion of the chloride ions to HCl according to the respective stoichiometry can thus be e.g. come wholly or in part from water molecules that are coordinated in hydration shells of certain metal chloride hydrates. The absorption can take place in an absorption unit with countercurrent flow of gas and hydrochloric acid or with cocurrent flow of gas and hydrochloric acid.
    The second distillation unit is preferably connected to the absorption unit in a fluid-conducting manner in such a way that at least a part of the second bottom product in the absorption unit can serve as an absorption medium. The second distillation unit can e.g. be connected to the first distillation unit in a fluid-conducting manner via the absorption unit in such a way that the second bottom product is able to act as an absorption medium and the hydrogen chloride-enriched absorption medium is able to form at least part of the recyclable aqueous fluid.
    Alternatively, the absorption unit can be integrated into a bottom circulation of a distillation unit (preferably the second distillation unit) in such a way that part of the bottom product of this distillation unit (preferably the second bottom product) can act as an absorbent.
    In a particularly preferred embodiment, the absorption unit is fluidly connected to the distillation unit which is designed to carry out a distillation below the ambient pressure in such a way that the hydrogen chloride-depleted gas can be drawn off from the absorption unit into this distillation unit. The fluid-conducting connection of the absorption unit to this distillation unit is preferably on the gas side, so that the reduced pressure prevailing in the distillation unit allows a steady gas flow from the absorption unit into this distillation unit, e.g. via a valve. This in turn leads to a subsequent flow of hydrogen chloride gas (e.g. roasting gas) into the absorption unit. This particularly preferred embodiment has the
    surprising advantage that roasting gas leaks into the environment can be avoided particularly reliably. Each roasting gas-forming and roasting gas-carrying plant part of a plant for the production of aluminum oxide can then be designed for operation under ambient pressure. This is done in a particularly economical manner using the negative pressure that prevails in the distillation unit operated under ambient pressure.
    In a preferred unit according to the invention, the first distillation unit is designed to be able to carry out a distillation above the ambient pressure and the second distillation unit is designed to be able to carry out a distillation below the ambient pressure.
    In another unit according to the invention, the second distillation unit is designed to be able to carry out a distillation below the ambient pressure and the first distillation unit is designed to be able to carry out a distillation therein below the ambient pressure.
    The invention also relates to a process for the recovery of hydrogen chloride from
    a hydrochloric acid, contaminated with difficult or non-volatile impurities
    aqueous liquid, being
    the liquid in a vaporization unit forms a vapor containing hydrogen chloride and a liquid concentrate contaminated with the low-volatile or non-volatile impurities,
    the hydrogen chloride-containing steam is separated into a first top product and a first bottom product in a first distillation unit,
    an aqueous fluid containing hydrogen chloride is separated into a second top product and a second bottom product in a second distillation unit,
    in which
    - Distillation above ambient pressure is carried out in one of these two distillation units and distillation is carried out below ambient pressure in the other of these two distillation units, and
    - The first bottom product forms at least part of the hydrogen chloride-containing aqueous fluid.
    In general, at least a portion of the second bottom product is recycled to the first distillation unit.
    [0042] The method is preferably not an extractive distillation method. The bottom products of both distillation units are essentially free of additives, e.g. Salts or contain significantly lower concentrations of salts based on the output streams. The proportion of additives other than hydrogen chloride and water in both bottom products is preferably at most 20% by weight, particularly preferably at most 6% by weight and very particularly preferably at most 3% by weight. This means that the HCI top product of the distillation unit, which is operated at ambient pressure, is almost completely free of entrained contaminants due to additives, and it was surprisingly found that aluminum oxide can only be reliably obtained in the desired purity levels for this reason.
    In certain processes according to the invention, the top product of the distillation unit, in which the distillation is carried out above ambient pressure, is passed through a droplet separator. As a result, the total content of metallic impurities in this top product can be reduced to below 10 ppmw.
    The hydrochloric acid aqueous liquid contaminated with low or non-volatile impurities generally has at least 0.5% by weight, e.g. at least 1% by weight of dissolved metals and a hydrogen chloride content of at least 10% by weight, in particular at least 15% by weight, preferably at least 20% by weight, e.g. at least 25% by weight.
    The hydrochloric acid, contaminated with difficult or non-volatile impurities
    71717
    aqueous liquid can contain 0.1 to 12% by weight, in particular 0.3 to 9% by weight, e.g. 0.5 to 7% by weight aluminum; and 0.1 to 12% by weight, especially 0.3 to 9% by weight, e.g. 0.5 to 7% by weight of other metals; and 10 to 37% by weight, especially 15 to 35% by weight, e.g. Contain 20 to 35 wt .-% hydrogen chloride. The metals are in the liquid as ions, e.g. with a hydration shell or with coordinated or otherwise associated chloride counterions.
    The mass fractions of aluminum and other metals each relate to the aluminum or metal salt present as chloride, in the highest, stable oxidation state of the respective metal (iron is therefore taken into account as FeCl3s). The mass fraction of other metals relates to the sum of the mass fractions of all metals other than aluminum. According to a particularly preferred embodiment of the method according to the invention, the hydrochloric acid aqueous liquid, which is contaminated with low or non-volatile impurities, is formed by increasing the hydrogen chloride content of an aluminum-rich aqueous solution, e.g. by introducing a HCI-containing gas, and the aluminum chloride which precipitates is separated off by solid-liquid separation. The HOCI-containing gas is preferably formed at least partially from the top product of the distillation unit in which the distillation is carried out above ambient pressure.
    The refinements of the invention described in connection with the unit according to the invention also apply in connection with the method according to the invention and vice versa.
    Preferably, the method according to the invention also serves for the recovery of hydrogen chloride from a gas containing hydrogen chloride, e.g. Roasting gas containing hydrogen chloride, the hydrogen chloride-containing gas being brought into contact with an absorption medium in an absorption unit. The absorbent can then e.g. are formed at least partially from at least a part of at least one of the two bottom fractions. It goes without saying that the bottom fraction here is synonymous with the bottom product.
    Preferably, the first distillation unit is operated above the ambient pressure and the second distillation unit is operated below the ambient pressure. Alternatively, the second distillation unit can be operated above ambient pressure and the first distillation unit can be operated below ambient pressure. The person skilled in the art knows how the respective distillation unit can be designed for overpressure or underpressure operation.
    The invention also relates to a set, e.g. an assembly for the construction of a unit according to the invention for the recovery of hydrogen chloride from a hydrochloric acid, contaminated with heavy or non-volatile impurities, aqueous liquid; comprising - the evaporation unit (30) having
    an entrance,
    an outlet and
    a liquid drain, - the first distillation unit (10) having
    an entrance,
    an upper outlet and
    having a lower outlet, - the second distillation unit (20)
    an entrance,
    an upper outlet and
    a lower outlet, one of these two distillation units being designed to be able to carry out a distillation above the ambient pressure and the other of these two distillation units being designed to be able to carry out a distillation therein below the ambient pressure, and the set, e.g. the assembly, to interconnect the evaporation unit
    and the two distillation units is designed as described for the unit according to the invention. The set, e.g. the assembly, a connecting element, e.g. a line for establishing a fluid-conducting connection from the outlet of the evaporation unit to the inlet of the first distillation unit and / or a connecting element for establishing a fluid-conducting connection from the lower outlet of the first distillation unit to the inlet of the second distillation unit.
    It is understood that the set, e.g. the assembly, may also include the absorption unit described herein. The absorption unit then typically has a liquid inlet, a liquid outlet, a gas inlet and a gas outlet. The set, e.g. the assembly with the absorption unit is then designed to be connected to the evaporation unit and the two distillation units, as described for an inventive unit with an absorption unit. The set, e.g. the assembly can also comprise at least one connecting element with which a fluid-conducting connection can be established from at least one lower outlet from one of the distillation units to the liquid inlet of the absorption unit.
    The embodiments of the invention described here in connection with the unit according to the invention also apply in connection with the set according to the invention, e.g. in connection with the assembly according to the invention, and vice versa.
    [0053] The invention is illustrated by the following figures, without being restricted thereto.
    Figure 1, Figure 2 and Figure 3 show different configurations of the unit for recovering HCl.
    Figure 1 shows a unit 1 for the recovery of hydrogen chloride from a hydrochloric acid, with heavy or non-volatile impurities (dissolved aluminum and other metals here) aqueous liquid 31. The unit 1 has an evaporation unit 30 to form a hydrogen chloride-containing vapor 32 and a liquid concentrate 33 from the liquid 31. Evaporation unit details such as the heating unit for providing the heat required for the evaporation, a phase separator for returning entrained, metal-containing liquid droplets, are not shown. The unit 1 also has a first distillation unit 10 for separating the steam containing hydrogen chloride 32 into a first top product 12 and a first bottom product 13. Unit 1 also has a second distillation unit 20 for separating a second hydrogen chloride-containing aqueous fluid 21 into a second top product 22 and a second bottom product 23. The hydrogen chloride-containing aqueous fluid 21 is formed from the first bottom product 13, a partial stream 19 of the first bottom product 13 being discharged in order to counteract an accumulation of metal impurities in the distillation units. The fluid 11 returned to an upper region of the first distillation unit 10 is formed from the second bottom product 23. The distillation units 10, 20 shown in the figures are columns. For simplification, heating units for heating the column bottoms and cooling units for cooling the column heads are not shown. In the example illustrated here, the first distillation unit 10 is designed in order to be able to carry out a distillation therein above the ambient pressure. The second distillation unit 20 is designed in order to be able to carry out a distillation below the ambient pressure. The pump 18 conveys the bottom product 23 against a pressure drop. The seals, wall thicknesses and column materials required for the respective operating pressure of the respective column are not indicated. Likewise, the linings of the various units which are resistant to the action of hydrochloric acid or hydrogen chloride gas are also not shown. Tanks and heat exchangers are also not shown.
    In FIGS. 2 and 3, the same reference symbols have the same meaning as in FIG. 1. The units 1 according to the invention for the recovery of hydrogen chloride shown in FIGS. 2 and 3 also have an absorption unit 40. The absorption unit is used to absorb hydrogen chloride from a gas 41 containing hydrogen chloride (e.g. roasting gas)
    into an absorbent 42 to obtain a hydrogen chloride-enriched absorbent 43 and a hydrogen chloride-depleted gas 44.
    In the unit 1 of Figure 2, the second distillation unit 20 is fluidly connected to the absorption unit 40 so that the second bottom product 23 in the absorption unit 40 serves as an absorbent 42. The absorption unit 40 is connected in a fluid-conducting manner to the first distillation unit 10 in such a way that the absorption agent 43 enriched with hydrogen chloride forms the recirculated fluid 11. A part of the second bottom product 23 which has not passed into the hydrogen chloride-depleted gas 44 in the absorption unit 40 thus forms part of the recycled aqueous fluid 11, the fluid 11 also comprising absorbed portions of the hydrogen chloride-containing gas 41. In the absorption unit 40, the absorption medium 42 is guided in countercurrent from the top to the rising gas 41.
    In unit 1 of FIG. 3, absorption unit 40 is integrated into the bottom circulation of second distillation unit 20 in such a way that part of second bottom product 23 functions as absorbent 42. The hydrogen chloride-depleted gas 44 is drawn off into the second distillation unit 20, which - as described above for FIG. 1 - is designed in order to be able to carry out a distillation therein below the ambient pressure.
    REFERENCE SIGN LIST:
    Unit for the recovery of hydrogen chloride 1 first distillation unit 10 recyclable fluid 11 first top product 12 first bottom product 13 pump 18 partial flow 19 second distillation unit 20 aqueous fluid containing hydrogen chloride 21 second top product 22 second bottom product 23 evaporation unit 30 hydrochloric acid, with low or non-volatile
    Contaminated, aqueous liquid 31 Vapor containing hydrogen chloride 32 Liquid concentrate 33 Absorption unit 40 Gas containing hydrogen chloride 41 Absorbent 42 Absorbent enriched with hydrogen chloride 43
    hydrogen chloride depleted gas 44
    权利要求:
    Claims (15)
    [1]
    1. Unit (1) for the recovery of hydrogen chloride from a hydrochloric acid, contaminated with heavy or non-volatile impurities, aqueous liquid (31), comprising - an evaporation unit (30) for forming a hydrogen chloride-containing vapor (32) and one with the heavy or non-volatile impurities contaminated liquid concentrate (33) from the liquid (31),
    - A first distillation unit (10) for separating the hydrogen chloride vapor (32) into a first top product (12) and a first bottom product (13), and
    a second distillation unit (20) for separating an aqueous fluid (21) containing hydrogen chloride into a second top product (22) and a second bottom product (23),
    in which
    one of these two distillation units is designed to be able to carry out a distillation above the ambient pressure and the other of these two distillation units is designed to be able to carry out a distillation therein below the ambient pressure, and
    - The first distillation unit (10) is connected in a fluid-conducting manner to the second distillation unit (20) in such a way that at least part of the first bottom product (13) is able to form at least part of the aqueous fluid (21) containing hydrogen chloride.
    [2]
    2. Unit (1) according to claim 1, comprising
    a first distillation unit (10) for separating a fluid (11) which can be recycled into the distillation unit (10) and the steam (32) containing hydrogen chloride into the first top product (12) and the first bottom product (13),
    in which
    - The second distillation unit (20) is fluidly connected to the first distillation unit (10) in such a way that at least part of the second bottom product (23) is able to form at least part of the recyclable aqueous fluid (11).
    [3]
    3. Unit (1) according to claim 1 or 2 for the recovery of hydrogen chloride from a hydrochloric acid, aqueous liquid (31) loaded with heavy or non-volatile impurities and for the recovery of hydrogen chloride from a gas (41) containing hydrogen chloride, comprising - an absorption unit (40 ) for the absorption of hydrogen chloride gas from the gas (41)
    into an absorbent (42) to obtain a hydrogen chloride-enriched absorbent (43) and a hydrogen chloride-depleted gas (44).
    [4]
    4. Unit (1) according to claim 3, wherein at least one of the distillation units (10, 20) is fluidly connected to the absorption unit (40) such that at least a portion of at least one of the two bottom products (13, 23) in the absorption unit ( 40) can serve as an absorbent (42).
    [5]
    5. Unit (1) according to claim 4, wherein the second distillation unit (20) is fluidly connected to the absorption unit (40) in such a way that at least part of the second bottom product (23) in the absorption unit (40) acts as an absorption medium (42) can serve.
    [6]
    6. Unit (1) according to claim 3, wherein the second distillation unit (20) is fluidly connected via the absorption unit (40) to the first distillation unit (10) in such a way that the second bottom product (23) can act as an absorbent (42) and the hydrogen chloride enriched absorbent (43) is capable of forming at least a portion of the recyclable aqueous fluid (11).
    [7]
    7. Unit (1) according to claim 5, wherein the absorption unit (40) is integrated into a bottom circulation of the second distillation unit (20) in such a way that part of the second bottom product (23) can act as an absorbent (42).
    [8]
    8. Unit (1) according to claim 3, wherein the absorption unit (40) is fluidly connected to that distillation unit (10, 20) which is designed to be able to carry out a distillation below the ambient pressure in that the hydrogen chloride-depleted gas (44 ) can be removed from the absorption unit (40) into this distillation unit (10, 20).
    [9]
    9. The unit (1) according to claim 1, wherein the first distillation unit (10) is designed to be able to carry out a distillation therein above the ambient pressure and the second distillation unit (20) is designed to be able to carry out a distillation therein below the ambient pressure .
    [10]
    10. Unit (1) according to claim 1, wherein the second distillation unit (20) is designed to be able to carry out a distillation therein above the ambient pressure and the first distillation unit (10) is designed to be able to carry out a distillation therein below the ambient pressure .
    [11]
    11. A process for the recovery of hydrogen chloride from an aqueous hydrochloric acid, which is contaminated with non-volatile or non-volatile impurities, whereby - from the liquid (31) in an evaporation unit (30) a vapor (32) containing hydrogen chloride and a vapor containing the heavy or liquid concentrate (33) contaminated with non-volatile impurities is formed,
    the hydrogen chloride-containing vapor (32) is separated in a first distillation unit (10) into a first top product (12) and a first bottom product (13),
    an aqueous fluid (21) containing hydrogen chloride is separated in a second distillation unit (20) into a second top product (22) and a second bottom product (23),
    in which
    distillation above ambient pressure is carried out in one of these two distillation units and distillation is carried out below ambient pressure in the other of these two distillation units, and
    - The first bottom product (13) forms at least part of the hydrogen chloride-containing aqueous fluid (21).
    [12]
    12. The method according to claim 11, for the recovery of hydrogen chloride from a hydrochloric acid, with aqueous or non-volatile impurities loaded aqueous liquid (31) and for the recovery of hydrogen chloride from hydrogen chloride-containing gas (41), wherein in an absorption unit (40) the hydrogen chloride-containing gas ( 41) is brought into contact with an absorbent (42).
    [13]
    13. Use of hydrochloric acid for the absorption of hydrogen chloride from a gas containing hydrogen chloride formed during thermal decomposition.
    [14]
    14. Use according to claim 13, wherein the thermal decomposition comprises thermal decomposition of aluminum chloride hexahydrate.
    [15]
    15. Set for erecting a unit according to at least one of claims 1 to 10;
    full
    - The evaporation unit (30), having an inlet, an outlet and a liquid drain,
    - the first distillation unit (10), having an inlet, an upper outlet and a lower outlet,
    - The second distillation unit (20), having an inlet, an upper outlet and a lower outlet
    wherein one of these two distillation units is designed to be able to carry out a distillation above the ambient pressure and the other of these two distillation units is designed to be able to carry out a distillation therein below the ambient pressure,
    and the set is designed to connect the evaporation unit and the two distillation units to form a unit according to at least one of claims 1 to 10.
    3 sheets of drawings
    类似技术:
    公开号 | 公开日 | 专利标题
    EP2909132B1|2020-06-17|Method for concentrating aqueous hydrogen halide solutions
    DE2257037C2|1986-03-06|Process for the recovery of sulfuric acid from sulfuric acid diluted with water containing metal salts
    DE60021308T2|2006-04-27|Process for the preparation of | acrylic acid
    DE2208102B2|1979-04-12|Process for removing sulfur dioxide from a gas containing sulfur dioxide
    DE202020101571U1|2020-04-08|HCl recovery unit
    DE4201494A1|1993-02-18|METHOD FOR PURIFYING RAW SALT ACID
    EP0180925A2|1986-05-14|Process for the preparation of vinyl chloride by thermal splitting of purified 1,2-dichloroethane
    DE2652524A1|1977-05-26|PROCESS FOR SEPARATION OF ACID GASES AND AMMONIA FROM YOUR DILUTED, Aqueous SOLUTIONS
    DD143596A5|1980-09-03|CONTINUOUS METHOD FOR OBTAINING PURE ALUMINUM OXIDE
    DE3018665A1|1980-12-18|METHOD AND DEVICE FOR REGENERATING SULFURIC ACID
    WO2014106667A2|2014-07-10|Method for the solvolysis of aqueous organic suspensions and solutions to form concentrated, aqueous, black-liquor-like and/or salt-like solutions of organic compounds
    DE3441080A1|1986-05-15|METHOD FOR PROCESSING THE PYROLYSIS PRODUCT FROM THE 1.2 DICHLORETHANE CLEAVAGE WITH HEAT RECOVERY
    DE2823972A1|1978-12-14|METHOD AND DEVICE FOR THE SEPARATION OF NITROGEN TRICHLORIDE FROM CHLORINE
    DE2331569A1|1974-01-17|METHOD OF TREATMENT OF CONSUMED ACID LIQUID
    EP1899287B1|2013-09-18|Method and device for using reaction heat during the production of 1,2-dichlorethane
    EP2439175B1|2015-06-17|Method for waste lye oxidation under increased pressure
    DE102011111316A1|2013-02-28|Purifying and concentrating hydrogen fluoride containing sulfuric acid, comprises stripping hydrogen fluoride containing sulfuric acid with steam in countercurrent manner, to obtain stripped sulfuric acid, and concentrating sulfuric acid
    US20120241309A1|2012-09-27|Process for Purifying Processing Fluids
    DE1567575A1|1970-07-16|Process for cooling chlorine and heating brine
    DE4230266A1|1994-03-17|Method and device for heat recovery in the chemical degradation of sewage sludge or waste water
    DD290858A5|1991-06-13|INDUSTRIAL PROCESS FOR SEPARATION AND RECOVERY OF CHLORINE
    CN106868325A|2017-06-20|A kind of method of scandium-enriched in hydrochloric acid leaching ilmenite production rich-titanium material flow
    DE1670026A1|1972-03-02|Process and apparatus for the production of a cyanuric chloride solution from gaseous cyanuric chloride
    EP1877387B1|2010-10-06|Method and device for crystallizing melamine
    DE2251696A1|1973-05-03|IMPROVED PROCESS FOR OXYCHLORINATION OF AETHYLENE
    同族专利:
    公开号 | 公开日
    CN113614028A|2021-11-05|
    AU2020222023A1|2021-09-30|
    DE202020101571U1|2020-04-08|
    WO2020165462A1|2020-08-20|
    DE102019204498A1|2020-10-01|
    EP3947270A1|2022-02-09|
    AT16772U3|2021-04-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US5174865A|1991-01-25|1992-12-29|Dow Deutschland Inc.|Process for purifying crude hydrochloric acid|
    DE10250131A1|2002-10-28|2004-05-06|Basf Ag|Process for the production of chlorine from hydrochloric acid|
    TN2016000187A1|2013-11-25|2017-10-06|Enviro Water Minerals Company Inc|System and mehtod for removing minerals from a brine using electrodialyis.|
    AU2014253487A1|2014-02-26|2015-09-10|Altech Chemicals Australia Pty Ltd|A method for the preparation of alumina|
    WO2017039439A1|2015-08-31|2017-03-09|Avantium Knowledge Centre B.V.|Process for the recovery of hydrochloric acid|
    CA3046151A1|2016-12-13|2018-06-21|Avantium Knowledge Centre B.V.|Process for purifying a contaminated hydrochloric acid composition|
    AU2018101228A4|2017-09-22|2018-09-27|Altech Chemicals Australia Pty Ltd|A method for the preparation of alumina|WO2022018076A1|2020-07-22|2022-01-27|Sgl Carbon Se|High pressure desorption of hydrogen chloride gas|
    法律状态:
    2021-04-15| HA| Change or addition of new inventor|Inventor name: CHRISTIAN WOLTZ, DE Effective date: 20210216 Inventor name: ODON DE JESUS ANGELES PALACIOS, DE Effective date: 20210216 Inventor name: MARTIN KIBILI, DE Effective date: 20210216 Inventor name: CHRISTOPHER LEUSCHNER, DE Effective date: 20210216 |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102019204498.0A|DE102019204498A1|2019-03-29|2019-03-29|HCl recovery unit|
    [返回顶部]