JP2014172786A - Apparatus for producing hydroxylammonium salt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for producing a hydroxyl ammonium salt, which can prevent corrosion of a reaction vessel where a reductive reaction is carried out and can produce a hydroxylammonium salt with suppressed performance deterioration due to the corrosion.SOLUTION: A production apparatus 100 is an apparatus for producing a hydroxylammonium salt by reducing nitrogen monoxide with hydrogen in an acidic medium in the presence of a catalyst. The production apparatus 100 comprises a reaction vessel 1, a first gas supply part 2, a second gas supply part 3, and a temperature control part 4. The reaction vessel 1 stores an acidic medium having a catalyst dispersed, in which a reduction reaction is carried out, and at least a portion thereof which comes into contact with the acidic medium is formed of two-phase stainless steel. The first gas supply part 2 supplies nitrogen monoxide to the reaction vessel 1, and the second gas supply part 3 supplies hydrogen to the reaction vessel 1. The temperature control part 4 controls temperature of the reaction vessel 1 at a predetermined value.

Description

  The present invention relates to a production apparatus for producing a hydroxylammonium salt.

  Hydroxyl ammonium salt is used as a raw material for producing cyclohexanone oxime for producing caprolactam, in addition to uses such as antioxidants, stabilizers, fiber dyes, and analytical reagents.

  Hydroxyl ammonium salt can be produced by reducing nitric oxide with hydrogen in an acidic medium such as an aqueous sulfuric acid solution in the presence of a catalyst (see Patent Document 1).

  For example, when sulfuric acid is used as the acidic medium and hydroxylammonium sulfate is produced as the hydroxylammonium salt, the reaction tank in which the reduction reaction is performed needs to be formed of a material excellent in sulfuric acid resistance.

  Stainless steel such as SUS304 and SUS316, depending on the type, conditions, etc., at a temperature around room temperature (25 ° C.), sulfuric acid having a low concentration of 5 to 10% by mass and a high concentration of 90% by mass or more, Has corrosion resistance.

  By using a material having a high content of Si, Mo and Cu, the concentration range of sulfuric acid having corrosion resistance is expanded, and the main component containing Mo and Cu at high Ni is 18Cr-18Ni-2Mo-2Cu (the numerical value is mass%) The remainder is Fe and inevitable impurities.) Stainless steel has corrosion resistance to sulfuric acid in a wide temperature range and concentration range.

  As such materials, warsite (22Cr-22Ni-2.2Mo-1.6Cu), carpenter 20 (20Cr-29Ni-2.3Mo-3.5Cu), iridium R (22Cr-64Ni-4Mo-2.5Cu). However, relatively low-cost DIN4577 (25Cr-25Ni-2Mo-0.3Ti) can be used for sulfuric acid having a low temperature of 50 ° C. or lower. “DIN” is a symbol representing the German Industrial Standard.

JP-A-8-34610

  However, when producing a hydroxylammonium salt, when a reaction vessel formed by DIN4577 is used as a reaction vessel in which a reduction reaction is performed, the reason is not clear if it is used over a long period of time. Corrosion may occur due to the approaching concentration and temperature of the boundary having corrosion resistance due to the fluctuation of the surface. Thus, when corrosion generate | occur | produces in a reaction tank, it may lead to the performance deterioration of the hydroxylammonium salt which is a manufacturing target object resulting from the corrosion.

  Therefore, an object of the present invention is to produce a hydroxylammonium salt in a production apparatus for producing a hydroxylammonium salt, in which the corrosion of the reaction tank in which the reduction reaction is performed is suppressed and the performance deterioration due to the corrosion is suppressed. It is providing the manufacturing apparatus which can do.

The present invention relates to a production apparatus for producing a hydroxylammonium salt by reducing nitric oxide with hydrogen in an acidic medium in the presence of a catalyst.
A reaction tank for storing an acidic medium in which a catalyst is dispersed, wherein at least a portion in contact with the acidic medium is formed from a duplex stainless steel;
A first gas supply unit for supplying nitric oxide to the reaction vessel;
A second gas supply unit for supplying hydrogen to the reaction vessel;
And a temperature adjusting unit for adjusting the reaction vessel to a predetermined temperature.
In the present invention, the acidic medium is sulfuric acid.

Moreover, in this invention, the said duplex stainless steel is the material containing Cr: 23-30%, Ni: 3-8%, Mo: 1-5% by the mass%.
Moreover, in this invention, the said predetermined temperature is 30-50 degreeC, It is characterized by the above-mentioned.

  According to the present invention, it is a production apparatus for producing a hydroxylammonium salt by reducing nitric oxide with hydrogen in an acidic medium in the presence of a catalyst. The manufacturing apparatus includes a reaction tank, a first gas supply unit, a second gas supply unit, and a temperature adjustment unit. The reaction tank stores an acidic medium in which a catalyst is dispersed, and a reduction reaction is performed. At least a portion in contact with the acidic medium is formed from duplex stainless steel. The first gas supply unit supplies nitric oxide to the reaction tank, and the second gas supply unit supplies hydrogen to the reaction tank. The temperature adjusting unit adjusts the reaction vessel to a predetermined temperature.

  In the production apparatus of the present invention, the acidic medium in which the catalyst is dispersed is stored, and in the reaction tank adjusted to a predetermined temperature by the temperature adjustment unit, the nitric oxide and the first gas supply unit and the second gas supply unit Hydrogen is supplied. Thereby, a reduction reaction for reducing nitric oxide with hydrogen is performed in the reaction vessel, and a hydroxylammonium salt can be produced. In the reaction tank in which such a reduction reaction is performed, at least a portion that contacts the acidic medium is formed of duplex stainless steel, so that corrosion of the reaction tank due to the reduction reaction can be suppressed. Therefore, it is possible to produce a hydroxylammonium salt in which performance deterioration due to corrosion of the reaction vessel is suppressed.

  Also according to the invention, the acidic medium is preferably sulfuric acid. By using sulfuric acid as the acidic medium, hydroxylammonium sulfate can be produced as the hydroxylammonium salt. When sulfuric acid is used as the acidic medium, the corrosion of the reaction tank becomes significant, but even in such a case, at least the portion that contacts the acidic medium is formed by the duplex stainless steel. Corrosion of the reaction tank due to the reaction can be suppressed.

  Moreover, according to this invention, it is preferable that a duplex stainless steel is the material containing Cr: 23-30%, Ni: 3-8%, Mo: 1-5% by the mass%. The duplex stainless steel having such a composition is a material having a high effect of suppressing corrosion due to a reduction reaction. Therefore, by using the duplex stainless steel having the above composition as the material constituting the reaction tank, corrosion of the reaction tank due to the reduction reaction can be suppressed over a long period of time.

  Moreover, according to this invention, it is preferable that a temperature adjustment part adjusts the temperature of the reaction tank at the time of a reduction reaction to 30-50 degreeC. The effect of suppressing the corrosion due to the reduction reaction of the duplex stainless steel is more remarkable at 30 to 50 ° C. in a relatively low temperature range. Therefore, by adjusting the temperature of the reaction vessel to 30 to 50 ° C. during the reduction reaction, corrosion of the reaction vessel due to the reduction reaction can be suppressed over a long period of time.

It is a figure which shows the structure of the manufacturing apparatus 100 which concerns on embodiment of this invention.

  FIG. 1 is a diagram showing a configuration of a manufacturing apparatus 100 according to an embodiment of the present invention. The production apparatus 100 is an apparatus for producing a hydroxylammonium salt by reducing nitric oxide with hydrogen in an acidic medium in the presence of a catalyst.

  The manufacturing apparatus 100 includes a reaction tank 1, a first gas supply unit 2, a second gas supply unit 3, and a temperature adjustment unit 4.

  The reaction tank 1 stores an acidic medium in which a catalyst is dispersed and performs a reduction reaction, and at least a portion in contact with the acidic medium is formed from duplex stainless steel. The reaction vessel 1 may be entirely formed from duplex stainless steel, or only the inner layer portion may be formed from duplex stainless steel. The reaction tank 1 is formed in a bottomed cylindrical shape (for example, a bottomed cylindrical shape), and includes a main body 12 that houses an acidic medium in which a catalyst is dispersed, and a lid that is detachably provided at an opening of the main body 12. Part 11.

  In the reaction tank 1, a gas supply opening 121 is provided on the side wall of the main body 12. The gas supply opening 121 forms an opening through which nitrogen monoxide derived from the first gas supply unit 2 described later and hydrogen derived from the second gas supply unit 3 are supplied into the reaction tank 1. . Nitric oxide and hydrogen supplied from the gas supply opening 121 are injected into an acidic medium accommodated in the main body 12 and in which the catalyst is dispersed.

  Further, in the reaction tank 1, the lid portion 11 is provided with an exhaust gas opening 111. The exhaust gas opening 111 forms an opening for discharging the exhaust gas generated when the reduction reaction of nitrogen monoxide with hydrogen is performed in the reaction tank 1 to the outside of the reaction tank 1.

  Further, the reaction tank 1 is provided with a stirring means 13 for stirring the acidic medium accommodated in the main body portion 12. The stirring means 13 is provided at a rod-shaped shaft portion 131 provided through the lid portion 11, a stirring blade 132 fixed to one end portion of the shaft portion 131, and the other end portion of the shaft portion 131. And a stirring drive unit 133 that rotates 131. In the stirring means 13, the stirring blade 132 rotates as the shaft portion 131 is rotated by the stirring driving unit 133, thereby stirring the acidic medium accommodated in the main body 12. By stirring the acidic medium by the stirring means 13, the catalyst is dispersed in the acidic medium.

  Furthermore, when the reduction reaction of nitric oxide with hydrogen is performed in the reaction tank 1, the pressure in the reaction tank 1 is normally maintained at atmospheric pressure, but is maintained at a pressure of 4 MPa or less. Also good.

  Here, a mineral acid such as sulfuric acid, nitric acid, hydrochloric acid, or phosphoric acid is used as the acidic medium stored in the reaction tank 1 and coexisting during the reduction reaction. The concentration of the free acid is preferably 0.1 to 5N. As the acidic medium, sulfuric acid is preferable among the mineral acids. By using sulfuric acid as the acidic medium, hydroxylammonium sulfate can be produced as the hydroxylammonium salt. When sulfuric acid is used as the acidic medium, the corrosion of the reaction tank 1 becomes significant, but even in such a case, at least a portion in contact with the acidic medium is formed of the duplex stainless steel. Corrosion of the reaction tank 1 due to the reduction reaction can be suppressed.

  Moreover, as a catalyst used at the time of a reduction reaction, the platinum catalyst carry | supported on support | carriers, such as a graphite, activated carbon, a silica, an alumina, can be mentioned. As such a platinum catalyst, a catalyst such as thiosulfate such as sodium thiosulfate or a mixture of thiosulfate and an alkali metal sulfide such as sodium sulfide as described in JP-A-1-15956 is used. It is preferable to use a catalyst prepared by reducing a platinum compound in the presence of a support.

  Even if the catalyst is used as it is, the hydroxylammonium salt can be obtained with high selectivity, but further reduction with a reducing agent may be performed. As the reducing agent, hydrogen, alcohol, formic acid, hydrazine or the like is used. Further, a method of reducing a platinum compound in the presence of the third component metal salt may be applied. As the third component, metal salts such as gold, silver, iridium, mercury, lead, arsenic, antimony, bismuth, selenium or tellurium are used. As salts of various metals, hydrochloride, nitrate, sulfate and the like are used. The amount used is not particularly limited, but is selected from the range of 0.001 to 0.2 in terms of the atomic ratio of metal to platinum.

  The first gas supply unit 2 derives nitric oxide and supplies the derived nitric oxide to the reaction tank 1. Between the 1st gas supply part 2 and the gas supply opening part 121 of the reaction tank 1, the 1st piping 5 in which the 1st flow control part 51 and the 2nd flow control part 52 were provided is connected. In the first pipe 5, the first flow rate adjustment unit 51 is arranged on the first gas supply unit 2 side, and the second flow rate adjustment unit 52 is arranged on the reaction tank 1 side. The flow rate of the nitric oxide derived from the first gas supply unit 2 is adjusted by the first flow rate adjustment unit 51 and the second flow rate adjustment unit 52 and flows through the first pipe 5. Through the reaction tank 1.

  The second gas supply unit 3 derives hydrogen and supplies the derived hydrogen to the reaction tank 1. Between the 2nd gas supply part 3 and the 1st piping 5, the 2nd piping 6 in which the 3rd flow volume adjustment part 61 was provided is connected. In the second pipe 6, one end is connected to the second gas supply unit 3, and the other end is connected between the first flow rate adjustment unit 51 and the second flow rate adjustment unit 52 in the first pipe 5. The hydrogen derived from the second gas supply unit 3 has its flow rate adjusted by the third flow rate adjustment unit 61 and flows through the second pipe 6, and further flows into the first pipe 5 from the other end of the second pipe 6. And flows through the first pipe 5 and is supplied into the reaction tank 1 through the gas supply opening 121.

  In the manufacturing apparatus 100 of the present embodiment, nitrogen monoxide derived from the first gas supply unit 2 and hydrogen derived from the second gas supply unit 3 are mixed in the first pipe 5 to supply gas. It is supplied into the reaction tank 1 through the opening 121. The molar ratio of nitric oxide and hydrogen supplied into the reaction vessel 1 is in the range of nitric oxide: hydrogen = 1: 1 to 1: 6, preferably 1: 1.5 to 1: 5. .

  The temperature adjustment unit 4 is provided so as to cover the main body 12 of the reaction vessel 1 from the outside, and adjusts the reaction vessel 1 to a predetermined temperature. It is preferable that the temperature adjustment part 4 adjusts the temperature (reaction temperature) of the reaction tank 1 at the time of the reduction reaction of nitric oxide with hydrogen to 30 to 50 ° C. The effect of suppressing the corrosion due to the reduction reaction of the duplex stainless steel is more remarkable at 30 to 50 ° C. in a relatively low temperature range. Therefore, by adjusting the temperature of the reaction tank 1 to 30 to 50 ° C. during the reduction reaction, corrosion of the reaction tank 1 due to the reduction reaction can be suppressed over a long period of time.

  In the manufacturing apparatus 100 of this embodiment, the acidic medium in which the catalyst is dispersed is stored, and nitrogen monoxide is supplied by the first gas supply unit 2 into the reaction tank 1 adjusted to a predetermined temperature by the temperature adjustment unit 4. Then, hydrogen is supplied by the second gas supply unit 3. Thereby, the reduction reaction which reduces nitric oxide with hydrogen is performed in the reaction tank 1, and a hydroxylammonium salt can be manufactured. In the reaction tank 1 in which such a reduction reaction is performed, at least a portion in contact with the acidic medium is formed of duplex stainless steel, so that corrosion of the reaction tank 1 due to the reduction reaction can be suppressed. Therefore, a hydroxylammonium salt in which performance deterioration due to corrosion of the reaction tank 1 is suppressed can be produced.

  Next, the material which comprises the reaction tank 1 is demonstrated. As described above, in the reaction vessel 1, at least a portion in contact with the acidic medium is formed from duplex stainless steel.

  The duplex stainless steel constituting the reaction tank 1 is preferably a material containing Cr: 23 to 30%, Ni: 3 to 8%, and Mo: 1 to 5%. Examples of the duplex stainless steel having such a composition include SAF 2507, SAF 2707, and DP-3. The duplex stainless steel having the above composition is a material having a high effect of suppressing corrosion due to a reduction reaction. Therefore, by using the duplex stainless steel having the above composition as the material constituting the reaction tank 1, corrosion of the reaction tank 1 due to the reduction reaction can be suppressed over a long period of time. The corrosion resistance of such duplex stainless steel is based on the following experimental results.

(Experimental conditions)
The manufacturing apparatus 100 shown in FIG. 1 was operated under the following conditions.
・ Acid medium: 0.3-4.6N sulfuric acid ・ Catalyst: Platinum catalyst ・ Reactor 1 temperature: 40-45 ° C.

  And in the reaction tank 1, the test piece (size: 40 mm x 40 mm x 2 mm) of each steel material shown by Table 1 was installed for 1 year.

  Table 1 shows the composition of each steel material used in the experiment in mass%. For example, the duplex stainless steel SAF2507 used as a test piece is in mass%, C: 0.016%, S: 0.00. Contains 0002%, Cr: 24.64%, Ni: 6.76%, Mo: 3.78%, Cu: 0.095%, N: 0.25%, the balance being the composition of Fe and inevitable impurities It has a steel material. Further, the duplex stainless steel SAF2707 is, in mass%, C: 0.014%, S: 0.0005%, Cr: 26.49%, Ni: 6.48%, Mo: 4.81%, N: The steel material contains 0.41%, Co: 0.94%, and the balance is the composition of Fe and inevitable impurities. Further, the duplex stainless steel DP-3 is in mass%, C: 0.034%, S: 0.011%, Cr: 25.04%, Ni: 6.9%, Mo: 3.35%, It is a steel material containing Cu: 0.56%, N: 0.142%, W: 0.2%, and the balance having a composition of Fe and inevitable impurities.

(Evaluation method)
About the test piece of each steel material after installing in the reaction tank 1 for one year, weight reduction and the corrosion rate were evaluated.

<Weight reduction>
The weight reduction (g) of the test piece of each steel material was calculated from the weight measurement results before and after the experiment.

<Corrosion rate>
The first corrosion rate (g · m ⁻² · h ⁻¹ ) was calculated from the weight loss (g), the surface area of the test piece (m ² ), and the test time (h). A value obtained by multiplying the first corrosion rate by (8.76 / density) was calculated as a second corrosion rate (mm · yr ⁻¹ ).

(Experimental result)
The experimental results are shown in Table 2.

  As apparent from the experimental results in Table 2, the duplex stainless steels SAF2507, SAF2707, and DP-3 have a smaller weight loss and a lower corrosion rate than other steel materials.

  From this result, it can be seen that the duplex stainless steel is a material having a high corrosion inhibiting effect during the reduction reaction of nitrogen monoxide with hydrogen. Therefore, by using duplex stainless steel as a material constituting the reaction tank 1, corrosion of the reaction tank 1 due to a reduction reaction can be suppressed over a long period of time.

DESCRIPTION OF SYMBOLS 1 Reaction tank 2 1st gas supply part 3 2nd gas supply part 4 Temperature adjustment part 5 1st piping 6 2nd piping 11 Cover part 12 Main body part 13 Stirring means 51 1st flow control part 52 2nd flow control part 61 1st 3 Flow Control Unit 100 Manufacturing Device 111 Exhaust Gas Opening Portion 121 Gas Supply Opening Portion 131 Shaft Portion 132 Stirring Blade 133 Stirring Driving Unit

Claims (4)

In a production apparatus for producing a hydroxylammonium salt by reducing nitric oxide with hydrogen in an acidic medium in the presence of a catalyst,
A reaction tank for storing an acidic medium in which a catalyst is dispersed, wherein at least a portion in contact with the acidic medium is formed from a duplex stainless steel;
A first gas supply unit for supplying nitric oxide to the reaction vessel;
A second gas supply unit for supplying hydrogen to the reaction vessel;
An apparatus for producing a hydroxylammonium salt, comprising: a temperature adjusting unit that adjusts the reaction tank to a predetermined temperature.   The apparatus for producing hydroxylammonium salt according to claim 1, wherein the acidic medium is sulfuric acid.   3. The hydroxylammonium salt according to claim 1, wherein the duplex stainless steel is a material containing Cr: 23 to 30%, Ni: 3 to 8%, and Mo: 1 to 5%. manufacturing device.   The said predetermined temperature is 30-50 degreeC, The manufacturing apparatus of the hydroxylammonium salt as described in any one of Claims 1-3 characterized by the above-mentioned.

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