SU923941A1 - Process for producing technical hydroxylamine sulphate - Google Patents

Description

The invention relates to the industrial production of hydroxylamine sulfate (GAS - raw materials for the production of caprolactam) and can be used in all plants producing GUS by catalytic reduction of nitric oxide using converted nitrogen as a hydrogenating agent.

A method of obtaining gas with the use of nitric oxide and hydrogen, containing impurities of other gases. The essence of the method lies in the fact that the gaseous mixture of nitric oxide with hydrogen, containing impurities Ν, ίχπ ΝςΟ, is passed through an aqueous solution of mineral acid,

In which a finely dispersed catalyst is suspended. The reaction proceeds. by equation

2Ν0 + ЗНо + (№1 ₃ 0Н) _g 50 ₄

Platinum, palladium or gold is used as a catalyst.

then on carriers with a developed surface [13.

The disadvantages of this method are the high consumption of raw materials and low GAS output.

Closest to the proposed technical essence and the achieved result is a method for the production of gas with the use of converted gas and nitric oxide containing an admixture of oxygen, including the stage afterburning of residual oxygen in nitric oxide and catalytic hydrogenation of nitric oxide.

Nitric oxide, necessary for the synthesis of gas, is obtained by the oxidation of ammonia on a platinum-rhodium catalyst with the addition of water vapor to the ammonia-air mixture. For

_Μ afterburning of residual oxygen in

nitric oxide used converted gas in the amount of 120 nmts.

For the synthesis of gas the oxide is mixed

nitrogen with an N0 content of at least

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93% in the amount of 500-20000 nm ³ / h and the converted gas in the amount of 800-3500 nm ³ / h. Converted gas has a composition,%: 92-94,

.4ο.4-5, _ ₄ 0Η ₄ 2-3, CO up to 0.004, H ^ 5 0.26 * 10. Pressure 3 ”4 MPa, temperature 20-40 ° С. Convertible gas is used at the stage of afterburning of residual oxygen in nitrogen oxides and at the stage of GAS synthesis.

The synthesis gas enters the first group of reactors, filled with a suspension of fine platinum catalyst in sulfuric acid. Converted gas and nitric oxide interact in dilute sulfuric acid at 40-45 ^ 0 and a pressure of 0.101793 "0.10395 MPa in the presence of a catalyst slurry - platinum on

graphite The reaction proceeds with vigorous stirring. The resulting solution gas is taken through the filters, and the catalyst is returned in the form of a suspension in the reactor. The reacted gases from the reactors of the first group are fed to the reactors of the second group. N0 in the amount b0 ~ 90 nm ^ / h is added here. Formed in the reaction process in the second group of reactors, gaseous by-products containing 3-10% Ν ^ Ο, 20102%

Να + СН ₄ , as well as 50-60% Н ^ and 15-20%

N0, in the amount of 1000-1400 nm ^ / h output to the torch. The liquid phase is removed from the solutions with a GAS content of at least 265 g / l (in terms of 100% hydroxylamine 110 g / l) in an amount of 5.3 “22.3 m ^ / h [2].

The presence of methane in the converted gas leads to the fact that carbon monoxide is formed at the stage of afterburning of residual oxygen in nitrogen oxides, which at the stage of HAS synthesis reversibly poison platinum catalysts. This leads to a low gas output of 75%.

The presence in the converted gas "ballast" of nitrogen and methane leads to a decrease in the production of gas and the unsustainable consumption of large amounts of raw materials (more than 1000 nm / h of gas containing 50-65% H <1, 15 “20% N0 is emitted to the torch).

Hydrogen sulfide, present in ‘in the converted gas, irreversibly poisons expensive platinum catalysts. This leads to the need to regenerate platinum catalysts every 4 days and limits the lifetime of the catalysts to three years.

The purpose of the invention is to increase the yield of hydroxylamine sulfate, reducing the amount of exhaust gases and increasing the service life of platinum catalysts.

This goal is achieved by the fact that in the process of obtaining technical hydroxylamine sulfate from converted gas and nitrogen oxide containing oxygen admixture, including the steps of afterburning residual oxygen in nitric oxide and subsequent catalytic hydrogenation of nitric oxide, the converted gas is passed through membranes from polyvinyltrimethylsilane and hydrogen-enriched gas is directed to the stage of afterburning of residual oxygen, in-nitrogen oxide and to the stage rolled tic hydrogenation of nitric oxide and non-diffundundi ripped gas is removed from the process.

The use of polyvinyltrimethylsilane membranes reduces the concentration in the hydrogen-rich converted gas by 3 times and as a result increases the range between regeneration of platinum catalysts up to 8-10 days, and the service life of platinum catalysts also increases 2-2.5 times.

Reducing the concentration of methane in the converted gas 4 times leads to a decrease in the concentration of carbon monoxide formed at the stage of afterburning of residual oxygen in nitric oxide 5 times.

The concentration of 40 in the diffusant is 0.05-10 *, i.e. decreases 6 times after passing through polyvinyltrimethylsilane membranes. As a result, the poisoning of the platinum catalyst with carbon monoxide is reduced, the catalyst activity increases and the GAS yield increases.

As a result of an increase in the concentration of hydrogen in the converted gas by 6%, the yield of HAS increases by at least 6%. The release of HAS per hour is increased by 600 kg (due to an increase in the concentration of hydrogen and an increase in the activity of the catalyst) and amounts to 5.67 tons (84% of the theoretical). Emission amount

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is 5

2 times

And _g 5

gases, decreases to 600 nm / m. The gas permeability coefficients of all the components of the converted gas through polyvinyltrimethylsilane are determined by mass spectrometry under laboratory conditions.

Gas permeability coefficients of various gases through polyvinyl trimethylsilane, m ³ m / m ^ MPa10: Ηιχ 6.54,

N <2 0.30, CH ₄ 0.70, CO 0.54,

1.42.

Hydrogen has a higher gas permeability through polyvinylmethylsilane compared to other gases, so it penetrates through polymer membranes more easily and enters the enriched gas mixture. The hydrogen concentration in the enriched gas mixture is 98-99%. The nitrogen concentration in the hydrogen-enriched gas mixture decreases. 7 times, methane 4 times, carbon monoxide 6 times, hydrogen sulfide 3 times.

The method is as follows.

12000 nm ³ / h of the converted gas having the composition of%: Ho.93 "α. 4.9 *, CH ₄ 2.1; CO 0.3-Yu * Η <χ5 0.2bH10 ^% (temperature 40 ° С, pressure 4 MPa), enters the diffusion apparatus, in which it is divided into two streams. The first stream enriched with hydrogen, having a composition,%: ^ ιΐ98,8-, Νο.0,7; .

CH ₄ 0.5; with 0.05-10 ^ -, ⁿ <2 ⁵ 0.08-10,.

(pressure 1.5 MPa), a value of 3000 nm7h ', is sent to the stage of afterburning of residual oxygen in nitrogen oxide (100.0 nm-3 / h) and to the stage of catalytic hydrogenation of nitrogen oxide (2900 nm ^a / h). The second stream, non-diffused gas, containing 90.8% And o. (pressure 4 MPa), the value of 90θθ nm ³ / h enters the stage * of benzene hydrogenation. * ₄₅

For processing 12000 nm® / h of converted gas at a given level, about 80 m of asymmetric polyvinyltrimethylsilane membrane is required.

Nitric oxide, purified from oxygen, is fed to the stage of synthesis of HAS in the amount of 1620 nm ³ / h. A mixture of 1620 nm® / h of nitric oxide and 2820 nm ′ / h (98.8%) of hydrogen enters the reactant-filled suspension, o

15

20

25

zo

50

ry of the first group, Zia platinum catalyst ⁵⁵ in the sulfuric acid.

/ VNIIPI

(prototype).

Circulation 514 Subscription Branch of the PPP "Patent", Uzhgrod, ul Proektnaya, 4

Order 2709/28

• The reaction of the formation of HAS occurs with vigorous stirring at 42-43 ^ 0 and a pressure of 0.102-0.103 MPa. The acid in the reactors is gradually neutralized. At the end of the reaction, the concentration of the free is 0.40.3 n. The resulting solution HAS taken through the filters, the catalyst is washed from the filter with a solution of sulfuric acid and return it to the reactor. Non-resorbed gases from the first group reactor are fed to the second group of reactors, N0 80 nm ^ / h is added here. The waste gases from the reactors in the amount of 600 nN ^ / h are fed to the flare.

The economic effect of the introduction of the proposed method is determined by the increase in the production of hydroxylamine sulfate, reducing the amount of exhaust gases sent to the flare, and the consumption of expensive platinum catalysts by reducing the concentration of hydrogen sulfide in the converted gas ...

Claims (1)

Claim A method of obtaining technical hydroxylamine sulfate from a converted gas and nitric oxide containing an oxygen impurity, which includes the stage of afterburning residual oxygen in nitric oxide and the subsequent catalytic hydrogenation of nitric oxide, which is characterized by the fact that plate catalysts, the converted gas is passed through polyvinyltrimethyl membranes before the stage of afterburning of residual oxygen in nitrogen oxide silane and hydrogen-enriched gas are directed to the stage of afterburning of residual oxygen in nitric oxide and to the stage of catalytic hydrogenation of nitric oxide, and the undifferentiated gas is removed from the process.