• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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    • 专利摘要:

    公开号:SE0850164A1
    申请号:SE0850164
    申请日:2008-12-19
    公开日:2010-06-20
    发明作者:Ritz N Ola；Naresh Jagjivandas Suchak
    申请人:Aga Ab；
    IPC主号:
    专利说明:

    15 20 25 30 N2O5 + HQO à 2HNO3 A scrubber is a device in which inflowing gas is exposed to very strong and turbulent mixing with a scrubber liquid. A scrubber usually contains filler bodies, so the contact surface gas / liquid becomes large.
    Such procedures to take care of. NOX [is described, inter alia, in U.S. Patents 6,162,409 and 5,985,223.
    In subsequent steps, the nitric acid formed can then be further treated. However, this is problematic, as there is a risk that nitrates will eventually leak into the environment.
    At the same time, the concentrations of nitric acid formed are so low that it is often not economically profitable to extract it.
    The present invention solves the problems described above.
    Thus, the invention relates to a process for pickling nettle material in a pickling bath, wherein reaction gases from the pickling containing NOX compounds are oxidized to form N 2 h, wherein the reaction gases are treated in a scrubber where the formed N to dissolve in the scrubber fluid and. hence. form HNO3, and is characterized in that the scrubber and the beet bath are made to communicate with each other so that the scrubber liquid and the beet liquid are made to be common to the scrubber and the beet bath.
    The invention will now be described in detail, with reference to exemplary embodiments of the invention and the accompanying drawings, in which: error! the number can not be represented in the given format., 2008-12-18 10 15 20 25 30 Figure 1 is a general view of a conventional pickling device; Figure * 2 is a schematic view of a pickling device in accordance with the present invention. in which Figure * 1 illustrates a conventional pickling bath 1, pickling of a metal material 2 is performed. The pickling bath can, for example, use a pickling acid in the form of a mixture of HF and HNO® to remove oxides from the surface of the metal material 2. A commonly used mixture is about 15% HNO3 and about 5% HF in water.
    In the pickling bath 1 there is arranged a stirring means 3, for example in the form of a pump, in order to set the pickling liquid in motion and thereby increase the pickling efficiency and repeatability.
    During pickling, NOX is formed, in the embodiment illustrated in Figure 1, approximately 10% NO and approximately 90% NO 2, although this distribution may vary depending on the particular application. This formed NOX is collected in gas phase in a hood 4 or equivalent, and is passed on to a device 5 which mixes ozone gas into the formed gases. In this case, in accordance with the above, a scrubber 6 is formed.
    N fl h, which is passed on to a per se conventional so In this a large contact surface is created between the gases led from the device 5 and water, so that nitric acid is formed. The nitric acid formed is discharged through an outlet pipe 7a for further treatment. The purified gas is discharged into a chimney 7b.
    For a normal-sized installation, typical concentrations of NOX formed in the gas removed from the beet bath 1 are between 1000 and 5000 ppm. In the same way, a typical outflow of errors! the number can not be represented in any format., 2008-12-18 10 15 20 25 30 reaction gases between 1000 and 15000 Nm / h. These values vary depending on how the process is designed in detail.
    All process steps take place in a humid environment and normally at a temperature exceeding the sublimation temperature of N 2 O 3. However, the temperature in the beet bath 1 may vary between about 20 and 95 ° C, preferably between 70 and 95 ° C.
    Figure 2 shows a bite step in accordance with the present invention. The reference numerals are the same as. those in Figure * 1 for corresponding parts.
    According to a preferred embodiment. the metal material 2 is stainless steel, and preferably elongate in the form of strip, sheet metal, wire, pipe, rod or the like. According to a preferred embodiment, the pickling takes place batchwise, according to another preferred embodiment it takes place continuously.
    According to the invention. they are oxidized at. the pickling. formed the NOX compounds so that N fi h is formed.
    According to a preferred embodiment, the NOX-containing reaction gases from the beet bath 1 are collected in the hood 4 and then led to the scrubber 6. On the way. they are mixed with ozone gas in the device 5, whereby bbO5 is formed as described above. Preferably, the residence time in the device 5, i.e. the time for mixing between reaction gases and ozone gas, before the reaction gases are introduced into the scrubber (6) for at least 2 seconds. In this way, the reaction between NOX compounds and ozone is allowed to proceed long enough to such as. for example at least 90%, a high proportion of NOm must be converted to NQO5. wrong! The scrubber (6) is then mixed in the scrubber (6), which in this position contains * significantly lower concentrations' of NOX, under very turbulent forms with the scrubber liquid so that it dissolved N5 O5 is dissolved in the scrubber liquid to form HNO3.
    According to the invention, the scrubber 6 and the beet bath 1 communicate with each other so that the scrubber liquid and the beet liquid are common to the scrubber 6 and the beet bath I. In other words, the beet liquid is also used as a scrubber liquid.
    Such an arrangement provides a number of advantages.
    First, the dissolved nitric acid is again used in the form of pickling acid by the enrichment of nitric acid in the scrubber liquid, which desires the need for filling of pickling acids in the pickling bath 1.
    Secondly, the problem of disposing of the nitric acid formed in the scrubber 6 is avoided, since it is instead used in the beet bath 1. In particular, the risk of the formed nitric acid being released into the environment and causing environmental damage is avoided.
    If HF is used as the beet liquid, part of the HF dissolved in the beet bath I will evaporate and accompany the gases to the scrubber, 6. In the scrubber. 6, they can again be partially dissolved in the scrubber liquid, in order to be returned again to the bite bath 1 in dissolved form by the liquid communication between the bite bath 1 and thus the further scrubber I. thereby. the advantage is added that a cycle of HF is achieved, where a part of the evaporated HF will be returned to the beet bath l. wrong! The number cannot be represented in the given format., 2008-12-18 10 15 20 25 30 The actual use of the beet liquid as a scrubber liquid can be achieved in several different ways.
    According to a particularly preferred embodiment, the pickling liquid is conveyed, via a pipeline and by means of one or more pumps 12, 13 or corresponding means and partly a temperature regulator - from the pickling bath 1 to the scrubber 6. tor 14, The pickling liquid is conveyed, via a pipeline 16, to the bottom of the scrubber 6 so that it is mixed with. the scrubber fluid. In addition. the beet liquid, via the pump 13, to the upper part of the scrubber 6, where it is spread in a conventional manner in the scrubber 6 through the scrubber's normal Scrubber liquid, in addition, function. via a pipe 15, from the bottom of the scrubber 6. and. again, via. the pump 13, to the upper part of the scrubber 6. In addition, scrubber liquid is carried from the bottom of the scrubber 6 back to the beet bath 1, via a pipeline 17. In this way a circulation of the common beet and scrubber liquid is achieved partly around the scrubber 6, partly back and forth between the beet bath 1 and the scrubber 6, which gives a good. enrichment 'of nitric acid. and the scrubber. 6 som. then can beet bath 1 to part. The temperature controller 14 makes it possible to control the temperature in the scrubber separately from the temperature in the beet bath, so that an optimal process temperature can be achieved in both vessels.
    In the event that HF is used as a beet liquid in combination with HNO®, * HF will partially evaporate from the beet bath 1 and again By dissolving with in the scrubber 6, according to the above. by means of the temperature regulator 14, which regulates the temperature of the beet liquid fed into the scrubber 6, maintains a temperature in the scrubber 6 which is lower than that in the beet bath 1, efficient recovery of gaseous HF in the scrubber 6 is achieved, namely the vapor pressure of HF increases sharply with increasing temperature, for which much more efficient discharge of HF can be achieved in the event of a fault! the number can not be represented in the given format., 2008-12-18 10 15 20 25 30 lower temperatures than at higher temperatures. To achieve an efficient HF cycle, according to a preferred embodiment, the temperature in the scrubber 6 is about ambient temperature or about 15-20 ° C, in other words about room temperature, and the temperature in the bath is at least about 60 ° C.
    According to another preferred embodiment, the ozone gas is supplied already in the beet bath 1, for example by bubbling ozone gas at the bottom of the beet liquid. In this way, the NOX compounds formed during pickling will react in whole or in part. with the ozone already in the beet liquid so that N fi h is formed, which is dissolved in In order to improve the pre-formed beet liquid and thus the HNOy forms for efficient formation of the HNO3 NOX compounds, in this case the beet liquid can be circulated in the beet bath 1 so strongly that substantially all formed NOX is reacted with ozone gas so that N fi h is formed in the beet bath 1. In other words, the scrubber 6 is arranged in this case as an integral part of the beet bath 1. It is preferred that the amount of ozone gas supplied is large enough and that the turbulence in the beet bath 1 is sufficiently strong. for the amount of NOX leaving the bed in this case to be less than about 100 ppm, preferably less than 50 ppm.
    According to another preferred embodiment, the ozone gas is supplied to the scrubber 6 itself. This has the advantage that the reaction time and surface area between the ozone gas and the NOX compounds are maximized.
    Preferred embodiments have been described above. However, it will be apparent to those skilled in the art that many changes may be made to the described embodiments without departing from the spirit of the invention. Thus, the invention should not be limited by errors! the number cannot be represented in the given format., 2008-12-18 the described embodiments, but can be varied within the scope of the appended claims. wrong! the number can not be represented in any format., 2008-12-18
    权利要求:
    Claims (11)
    [1]
    1. A process for pickling metal material (2) in a pickling bath (1), causing compounds to be oxidized to form N 2 h, wherein reaction gases from the pickling containing NOX- where the reaction gases are treated in a scrubber (6) where it formed N5 O5 is caused to dissolve in the scrubber liquid and thereby form HNO3, the characteristic rod and the bite bath (1) that the scrubber (6) is caused to communicate with each other so that the scrubber liquid and the bite liquid are made to be common to (1). the scrubber (6) and the beet bath
    [2]
    2. Process according to claim 1, characterized in that ozone gas is used as oxidizing agent to oxidize NOX to Nyh.
    [3]
    3. A process according to claim 2, characterized in that the reaction gases are caused to mix with the ozone gas before the reaction gases reach the scrubber (6).
    [4]
    A process according to claim 3, characterized in that the reaction gases are caused to mix with ozone gas for at least 2 seconds before the reaction gases are caused to reach the scrubber (6).
    [5]
    5. A method according to claim 2, 3 or 4, characterized in that the ozone gas is brought to be supplied already in the beet bath, which can be so strongly.
    [6]
    A method according to claim 5, that the beet liquid is circulated in the beet bath while substantially all of the NOX formed in the beet bath is caused to react with (1), (6) forming an integral part of the beet bath (1). ozone gas so that N fl h whereby the scrubber wrong! the number can not be represented in the specified format., 2008-12-18 10 15 20 25 10
    [7]
    7. A process according to claim 2, characterized in that the ozone gas is supplied to the reaction gases in the scrubber (6).
    [8]
    A method according to any one of the preceding claims, characterized in that the pickling liquid is caused to be carried from the pickling bath (1) aV to the scrubber (6) and back, but also in that the scrubbing liquid is simultaneously caused to circulate in a cycle from the scrubber ( 6) bottom to its upper part.
    [9]
    Method according to one of the preceding claims, characterized in that the metal material (2) is stainless steel.
    [10]
    Procedure according to any one of the preceding claims, k e n n e - t e c k n a t that EH used j. combination 1ned HNO3 in the beet bath (l) aV and by that temperature. in the scrubber (6) by means of a temperature regulator (14) is brought to control that (1). be lower than in the beet bath
    [11]
    11. ll. Process according to Claim 10, characterized in that the temperature. in the scrubber (6) is brought to be about room temperature while the temperature in the beet bath (1) is made to be at least about 60 ° C. wrong! the number can not be represented in the specified format., 2008-12-18
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    同族专利:
    公开号 | 公开日
    SE533919C2|2011-03-01|
    FI20096352A|2010-06-20|
    FI126236B|2016-08-31|
    FI20096352A0|2009-12-18|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2021-08-03| NUG| Patent has lapsed|
    优先权:
    申请号 | 申请日 | 专利标题
    SE0850164A|SE533919C2|2008-12-19|2008-12-19|Method of handling NOx compounds in metal pickling|SE0850164A| SE533919C2|2008-12-19|2008-12-19|Method of handling NOx compounds in metal pickling|
    FI20096352A| FI126236B|2008-12-19|2009-12-18|Procedure for pickling metal material|
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