RU2323035C2 - Method of removing hydrogen sulfide from oxygen-containing gases - Google Patents

Abstract

FIELD: gas purification.

SUBSTANCE: method comprises purifying gas in vortex chambers provided with a rotating gas-liquid layer and causing the gas to be in a contact with the liquid main absorber. The time interval for which gas stays within the layer ranges from 0.001 to 0.1. The absorber additionally has soluble catalyzer for oxidizing hydrosulfides by oxygen. The trapped hydrogen sulfide is oxidized in the vortex chamber producing soluble oxygen-containing composition of sulfur.

EFFECT: improved method.

3 cl, 1 tbl, 8 ex

Description

The invention relates to the field of purification from hydrogen sulfide of oxygen-containing gases, air and gas-air mixtures, in which the content of H ₂ S does not exceed the oxygen content, in particular gas-air mixtures generated by air blowing of hydrogen sulfide from spent solutions of ash in the processing of leather; flue gas production nitron fiber; gas-air emissions of degassing pits of liquid sulfur, etc.

A known method of purifying air from hydrogen sulfide by absorption with an absorbing solution containing an alkaline agent and cobalt phthalocyanine disulfonic acid (DSFC), followed by regeneration of the saturated absorber by blowing air with the formation of elemental sulfur (L. Rybakov, Alkaline-hydroquinone and alkaline-phthalocyanine cleaning methods of aspiration gases from hydrogen sulfide // Industrial and sanitary cleaning of gases. - M.: TSINTIHIMNEFTEMASH. - 1976. - No. 2. - C.2-3). The advantages of this method are a high degree of air purification and disposal of trapped hydrogen sulfide in the form of sulfur and sodium thiosulfate. The disadvantages of this method are the high capital costs for the installation of cleaning due to the fact that bulky devices are used: an absorber and a flotator (bubbler type device) with low-intensity gas / liquid mass transfer. The oxidation of trapped hydrogen sulfide in aqueous-alkaline solutions with air in bubblers occurs rather slowly even in the presence of highly active oxygenation catalysts for sulfur compounds with oxygen such as DSPK. The low rate of dissolution of oxygen in aqueous solutions limits the rate of oxidation of aqueous-alkaline solutions of hydrogen sulfide.

A known method of the oxidative purification of solutions of hydrogen sulfide in a centrifugal bubbler apparatus (CBA) using a cobalt tetrasodium salt tetrasodium sulfonate tetrasulfonate catalyst (TSFK) (Zavarukhin SG, Kuvshinov G.G., Gogina L.V., Kundo N.N. The intensification of the process of catalytic oxidative purification of solutions from hydrogen sulfide using a catalyst TSFK in a centrifugal bubble reactor // Chemical Industry, 1999. - No. 2, S.90-94). This method allows you to very quickly oxidize solutions containing hydrogen sulfide in a centrifugal bubbler apparatus (CBA). However, in the method described above, the product obtained by purification is elemental sulfur. When cleaning dilute solutions of hydrogen sulfide, this method may possibly be implemented on current CBAs, since an oxidized solution containing freshly formed finely dispersed sulfur is immediately removed from the treatment plant. But this method is not suitable for purification of gases from hydrogen sulfide, when the absorption solution circulates in the purification unit, and products from the oxidation of hydrogen sulfide accumulate in it, in this case elemental sulfur. Fine sulfur accumulating in the absorption solution, deposited on the walls of the liquid lines and the CBA, causes the clogging of these liquid lines and the "fouling" of the gray of the centrifugal bubbler apparatus, which makes its operation impossible.

Closest to the claimed method is a method for purifying process gases from hydrogen sulfide, including countercurrent contact of gases with the liquid main absorber and absorption of hydrogen sulfide by the absorber in the vortex chambers with a rotating gas-liquid layer with a residence time of gases in the layer from 0.001 to 0.1 sec (Pat. RF 2245897 , C10K 1/12, B01D 53/14, 53/52, 02/10/2005). The advantage of this method is that a high degree of gas purification from H ₂ S is achieved at low capital and operating costs due to the fact that a highly efficient mass transfer apparatus is used.

The disadvantage of the prototype is to obtain as a result of purification of highly toxic waste solutions of sulfides of alkali and alkaline-earth metals of high concentration. These solutions must be disposed of, which is not always easily practicable.

The technical problem is based on the invention: in the case of purification of oxygen-containing gases in which the hydrogen sulfide content does not exceed the oxygen content, or if it is possible to dose oxygen in the amount to be purified in which the hydrogen sulfide content does not exceed the oxygen content, carry out in a vortex chamber with a rotating gas-liquid layer not only the absorption of hydrogen sulfide from gas, but also the conversion of the captured hydrogen sulfide into non-toxic soluble oxygen-containing sulfur compounds, pre proprietary sulfates and thiosulfate.

The problem is solved by a method of purifying oxygen-containing gases from hydrogen sulfide in a vortex chamber with a rotating gas-liquid layer with a duration of gas stay in the layer from 0.001 to 0.1 s, including countercurrent contact of gases with the liquid main absorber and absorption of hydrogen sulfide by the absorber. Oxygen-containing gas is purified, in which the hydrogen sulfide content does not exceed the oxygen content. The absorber contains a soluble catalyst for the oxidation of hydrosulfide ions with oxygen to non-toxic soluble oxygen-containing sulfur compounds, mainly sulfates and thiosulfates.

As the catalysts, a soluble salt of divalent manganese, a cobalt phthalocyanine disulfonic acid, and a catalytic system containing cobalt phthalocyanine disulfonic acid and a soluble manganese salt can be used as catalysts.

In addition to the capture of hydrogen sulfide, in the vortex chamber with a rotating gas-liquid layer, in addition to the capture of hydrogen sulfide, the trapped hydrogen sulfide is also oxidized with oxygen to form non-toxic soluble oxygen-containing sulfur compounds, mainly sulfates and thiosulfates. The residence time of the liquid in the layer is from 10 to 15 s; the ratio of gas / liquid is, wt .: 1-3.

EFFECT: high degree of gas purification from hydrogen sulfide with its simultaneous utilization in the form of non-toxic soluble oxygen-containing sulfur compounds, mainly sulfates and thiosulfates.

The invention is illustrated by the following examples.

Example 1

A gas mixture with a flow rate of 100 m ³ / h is fed into the vortex chamber of a centrifugal bubbler apparatus (CBA) with a rotating gas-liquid layer. The duration of gas in the gas-liquid layer of the vortex chamber is 7 · 10 ^-3 s. The scheme provides for continuous circulation of the absorption solution supplied to the CBA vortex chamber. In accordance with the scheme, at the outlet from the CBA, gas purified from H ₂ S is obtained, which is emitted into the atmosphere.

A 0.001 M solution of Na ₂ CO ₃ with a pH of 8.2–8.4 is used as an absorber. The circulation rate of the absorption solution through the CBA vortex chamber is 0.83 dm ³ / min (0.5 dm ³ per 1 m ^{3 of} gas). A gas mixture containing 0.04 vol.% H ₂ S enters for cleaning, the rest is air.

At the same time as the supply of the gas mixture, the MnCl ₂ catalyst is dosed into the absorption solution in an amount providing a ratio of “hydrogen sulfide: catalyst” equal to 86.83 mol / mol.

The purification is carried out with continuous monitoring of the presence of hydrogen sulfide in the gas mixture at the outlet from the CBA and iodometric monitoring of the content of HS ^- in the absorption solution, as well as its oxidation products. The hydrogen sulfide content in the purified gas mixture does not exceed 5 mg / m ³ . The absorption solution at the outlet of CBA no H ₂ S, HS ^{- -} and S ^2- ions. The main oxidation products are sodium sulfate and sodium thiosulfate, elemental sulfur is absent. The installation operates in this mode for 72 minutes. The amount of purified gas is 120.24 m ³ , the amount of trapped and oxidized hydrogen sulfide is 2.16 g-mol (73.44 g).

Example 2

The same as in example 1, but the hydrogen sulfide content in the cleaned air-gas mixture is 0,067 vol.%.

The hydrogen sulfide content in the purified gas-air mixture does not exceed 5 mg / m ³ . The absorption solution at the outlet of CBA no H ₂ S, HS ^{- -} and S ^2- ions. The main oxidation products are sodium sulfate and sodium thiosulfate, elemental sulfur is absent. The installation works in this mode for 48 minutes. The amount of purified gas is 80.16 m ³ , the amount of trapped and oxidized hydrogen sulfide is 2.41 g-mol (81.94 g).

Example 3

The same as in example 2, but the ratio of "hydrogen sulfide: catalyst" is 17.36 mol / mol.

The hydrogen sulfide content in the purified gas mixture does not exceed 5 mg / m ³ . The absorption solution at the outlet of CBA no H ₂ S, HS ^{- -} and S ^2- ions. The main oxidation products are sodium sulfate and sodium thiosulfate, elemental sulfur is absent. The installation works in this mode for 78 minutes. The amount of purified gas is 131.93 m ³ , the amount of trapped and oxidized hydrogen sulfide is 3.96 g-mol (134.64 g).

Example 4

The same as in example 1, but the content of H ₂ S in the cleaned gas mixture is 0.14 vol.%.

The hydrogen sulfide content in the purified gas mixture does not exceed 5 mg / m ³ . The absorption solution at the outlet of CBA no H ₂ S, HS ^{- -} and S ^2- ions. The main oxidation products are sodium sulfate and sodium thiosulfate, elemental sulfur is absent. The installation works in this mode for 24 minutes. The amount of purified gas is 40.08 m ³ , the amount of trapped and oxidized hydrogen sulfide is 2.41 g-mol (81.94 g)

Example 5

The same as in example 4, but the ratio of "hydrogen sulfide: catalyst" is 17.36.

The hydrogen sulfide content in the purified gas mixture does not exceed 5 mg / m ³ . The absorption solution at the outlet of CBA no H ₂ S, HS ^{- -} and S ^2- ions. The main oxidation products are sodium sulfate and sodium thiosulfate, elemental sulfur is absent. The installation works in this mode for 43 minutes. The amount of purified gas is 73.48 m ³ , the amount of trapped and oxidized hydrogen sulfide is 4.41 g-mol (149.94 g).

Example 6

The same as in example 1, but the content of H ₂ S in the cleaned gas-air mixture is 0.15 vol.%, And the catalyst used is cobalt phthalocyanine disulfonic acid -CoPc (SO ₃ H) ₂ (DSPA), which in the absorption solution containing sodium carbonate is converted to cobalt phthalocyanine disulfonate disodium salt of CoPc (SO ₃ Na) ₂ . Moreover, DSPK is introduced into the absorption solution before the gas mixture is supplied at the rate of 1.28 · 10 ^-6 mol / dm ³ (1.00 mg / dm ³ CoPc (SO ₃ Na) ₂ ).

The hydrogen sulfide content in the purified gas mixture does not exceed 5 mg / m ³ . The absorption solution at the outlet of CBA no H ₂ S, HS ^{- -} and S ^2- ions. The main oxidation products are sodium sulfate and sodium thiosulfate, elemental sulfur is absent. The installation works in this mode for 24 minutes. The amount of purified air is 40.45 m ³ , the amount of trapped and oxidized hydrogen sulfide is 2.71 g-mol (92.14 g).

Example 7

The same as in example 6, but using a catalytic system comprising catalysts CoPc (SO ₃ H) ₂ and MnCl ₂ . The concentration of the CoPc (SO ₃ H) ₂ catalyst is 1.28 · 10 ^-6 mol / dm ³ (1.00 mg / dm ³ CoPc (SO ₃ Na) ₂ ), the concentration of the MnCl ₂ catalyst is 0.16 mg / dm ³ . The introduction of CoPc (SO ₃ H) ₂ and MnCl _{2 is} carried out in the same manner as in example 6.

The installation works in this mode for 36 minutes. The hydrogen sulfide content in the purified gas mixture does not exceed 5 mg / m ³ . The absorption solution at the outlet of CBA no H ₂ S, HS ^{- -} and S ^2- ions. The main oxidation products are sodium sulfate and sodium thiosulfate, elemental sulfur is absent. The installation works in this mode for 36 minutes. The amount of purified gas is 60.45 m ³ , the amount of trapped and oxidized hydrogen sulfide is 4.05 g-mol (137.70 g).

Example 8

The same as in example 7, but without first obtaining a mixture of catalysts in the absorption solution. The introduction of CoPc (SO ₃ H) ₂ in the absorption solution is carried out in the same way as in example 6, and in the same amount. The introduction of MnCl _{2 is} carried out by fractional dosing in an amount providing a feed ratio of "H ₂ S: MnCl ₂ " equal to 86.83 mol / mol.

The hydrogen sulfide content in the purified gas mixture does not exceed 5 mg / m ³ . The absorption solution at the outlet of CBA no H ₂ S, HS ^{- -} and S ^2- ions. The main oxidation products are sodium sulfate and sodium thiosulfate, elemental sulfur is absent. The installation operates in this mode for 40 minutes. The amount of purified air is 68.51 m ³ , the amount of trapped and oxidized hydrogen sulfide is 4.59 g-mol (156.06 g).

The data shown in examples 1-8 are summarized in table.

From the above examples and the table it follows that the proposed method allows to achieve a high degree of gas purification from hydrogen sulfide with its simultaneous utilization in the form of non-toxic soluble oxygen-containing sulfur compounds, mainly sulfates and thiosulfates.

Table 1 Examples No. The hydrogen sulfide content in the gas mixture,% vol. Catalyst Name The ratio of "hydrogen sulfide / MnCl ₂ /", mol / mol Unit operation time, min The amount of captured hydrogen sulfide, g-mol; (g) Notes one 0.04 MnCl ₂ 86.83 72 2.16; (73.4) 2 0,07 MnCl ₂ 86.83 48 2.41; (81.9) 3 0,07 MnCl ₂ 17.36 78 3.96; (134.6) four 0.14 MnCl ₂ 86.83 24 2.41; (81.9) 5 0.14 MnCl ₂ 17.36 43 4.41; (149.9) 6 0.15 CoCs (SO ₃ H) ₂ 24 2.71; (92.1) The content of CoPc (SO ₃ Na) ₂ in the absorption solution
1.28 · 10 ^-6 mol / dm ³ (1.0 mg / dm ³ ) 7 0.15 MnCl ₂
CoCs (SO ₃ H) ₂ 36 4.05; (137.7) The content of MnCl ₂ 1.28 · 10 ^-6 mol / dm ³ (0.16 mg / dm ³ ), the content of CoPc (SO ₃ Na) ₂ 1.28 · 10 ^-6 mol / dm ³ (1.00 mg / dm ³ ) 8 0.15 MnCl ₂
CoCs (SO ₃ H) ₂ 86.83 40 4.59; (156.1) The content of CoPc (SO ₃ Na) ₂ 1.28 · 10 ^-6 mol / dm ³ (1.00 mg / dm ³ ),
MnCl _{2 is} dosed into the solution at the same time as the feed gas mixture

Claims (4)

1. The method of purification of gases from hydrogen sulfide in vortex chambers with a rotating gas-liquid layer with a residence time of gases in the layer from 0.001 to 0.1 s, including countercurrent contact of gases with the liquid main absorber and absorption of hydrogen sulfide by the absorber, characterized in that the gas is cleaned, wherein the H ₂ S content is higher than the oxygen content, the absorber further comprises a soluble catalyst for the oxidation of oxygen hydrosulfides and wherein in the swirl chamber is also captured oxidation with rovodoroda oxygen to form soluble oxygenated sulfur compounds, predominantly sulfates and thiosulfates. 2. The method according to claim 1, characterized in that the catalyst used is a soluble salt of divalent manganese. 3. The method according to claim 1, characterized in that the catalyst used is a catalytic system containing cobalt phthalocyanine disulfonic acid. 4. The method according to claim 1, characterized in that the catalyst used is a catalytic system containing cobalt phthalocyanine disulfonic acid and a soluble divalent manganese salt.