Device, process, and catalyst intended for desulfurization and demercaptanization of gaseous hydrocarbons

Abstract

This application is in the field of technologies for desulfurization and demercaptanization of gaseous hydrocarbons. The device includes a catalytic reactor loaded with a catalyst solution in an organic solvent, a means of withdrawal sulfur solution from the reactor into the sulfur-separating unit, and a sulfur-separating unit. The said device has at least means of supplying gaseous hydrocarbon medium to be purified and oxygen-containing gas into the reactor, and a means of outletting the purified gas from the reactor. The sulfur-separation unit includes a means of sulfur extraction. The reactor design and the catalyst composition provide conversion of at least 99.99% of hydrogen sulfide and mercaptans into sulfur and disulfides. The catalyst is composed of mixed-ligand complexes of transition metals. The technical result achieved by use of claimed invention is single-stage purification of gaseous hydrocarbons from hydrogen sulfide and mercaptans with remaining concentration of SH down up to 0.001 ppm.

Claims

1. A device for desulfurization and demercaptanization of a gaseous hydrocarbon medium, comprising: a catalytic reactor containing an organic solvent of a catalyst for H.sub.2S oxidation and RSH oxidation into sulfur and disulfides respectively, a sulfur-separating unit, a means for withdrawing a sulfur solution from the reactor into the sulfur-separating unit, at least one means for supplying into the reactor a gas to be purified and an oxygen-containing gas, a means for outputting a purified gas from the reactor, wherein the sulfur-separating unit comprises a means for sulfur extraction, wherein a reactor design and a catalyst composition provide for at least a 99.99% conversion of hydrogen sulfide and mercaptans into sulfur and disulfides, and wherein the catalyst comprises mixed-ligand complexes of transition metals, the mixed-ligand complexes comprising cupric chloride and an amide, wherein the catalyst comprises a metal to amine ratio of at most 40 percent metal by weight and at least 60 percent amine by weight.

2. The device of claim 1, wherein the means for supplying a gas to be purified and an oxygen-containing gas comprises a means for homogenization of a mixture of hydrocarbon gas to be purified and an oxygen-containing gas.

3. The device of claim 1, wherein the reactor further comprises a means for distribution of a supplied gas flow evenly within the reactor or within one or more filling plates of said device.

4. The device of claim 1, wherein the device further comprises a means for metered supply of the catalyst.

5. The device of claim 1, wherein said mixed-ligand complexes are based on ferric and cupric halides.

6. The device of claim 1, wherein the sulfur-separating unit comprises a means for sulfur extraction from the sulfur solution and a means for recycling the sulfur solution thereafter.

7. The device of claim 1, wherein the amide is dimethylformamide (DMF).

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows the block diagram of the proposed device in the most appropriate composition, where the following notations are used: inlet pipe 1 that supplies raw medium to be purified, mixing unit 2 that mixes hydrocarbon gas to be purified with oxygen-containing gas, inlet pipe 3 that supplies oxygen-containing gas, agitator 4 of oxygen-containing gas discharge, pipe 5 that supplies mixture of hydrocarbon gas to be purified with oxygen-containing gas, catalytic reactor 6, means 7 of distribution of mixture of hydrocarbon gas and oxygen-containing gas in the volume of reactor 6 or filling plates, tank 8 containing catalyst solution, agitator 9 of metered supply of catalyst solution from tank 8 into reactor 6, pipe 10 that supplies catalyst solution into reactor 6, pipe 11 that outlets purified gas, pipe 12 that outlets sulfur suspension into sulfur-separating unit 13, pipe 14 of sulfur outlet from sulfur-separating unit 13, pipe 15 that outlets catalyst solution from sulfur-separating unit 13 into catalytic reactor 6 after sulfur has been separated, agitator 16 of catalyst solution recycling from sulfur-separating unit 13 into catalytic reactor 6.

(2) The general stages or the process realization are shown in FIG. 2, where the following notation is used: supplying raw hydrocarbon material mixed with oxygen-containing gas to the reactor17, passing the raw material through the reactor containing organic solution of the catalyst18, output of pure gas from the reactor, where the conversion of hydrogen sulfide and mercaptans to sulfur and disulfides is 99.99%19, usage of oxygen, not less than 50% of total amount of hydrogen sulfide and mercaptan sulfur20, distribution of gas mixture evenly in the reactor volume21, metered supply of the catalyst into the reactor22, separation of sulfur from the suspension and recycling of catalyst solution into the reactor23, maintaining of temperature in the device in range of 25-140? C.24.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(3) As an agitator of oxygen-containing gas discharge, an air compressor can be used, as an agitator of catalyst solution supply from the tanka metering pump, and as an agitator of catalyst solution recycling from sulfur-separating unitwhereby a regular pump can be used.

(4) Below, the essence and advantages of the developed technical solution are discussed in examples of practical implementation. a. Example 1. Synthesis of catalyst C1. Into a retort, at a room temperature, 10 ml of ethyl alcohol, 100 ml of octane, 0.2-1 g of CuCl.sub.2.2H.sub.2O and 0.5-3 g of amine (benzylamine, cyclohexamine, pyridine) are put. The contents of the retort are mixed until cupric chloride dissolves completely. This composition of the catalyst is disclosed in (RU, patent No. 2405738, issued 27 Apr. 2010). b. Example 2. Synthesis of catalyst C2. Into a retort, at a room temperature, 100 ml of ethyl alcohol, 20 ml of water, 20 ml (0.25 moles) of dimethylformamide (DMFA), and 15 g (0.09 moles) of CuCl.sub.2.2H.sub.2O are put. The contents of the flask are mixed until cupric chloride dissolves completely. This composition of the catalyst is known from (RU, patent No. 2398735, issued 10 Sep. 2010), however, even before the scientific research being a basis of current invention was finished, no data on demercaptanization capabilities of the said catalyst had been known.

(5) Example 3. Synthesis of catalyst C3. Into a retort, at a room temperature, 100 ml of alcohol, 8-60 g of amine-dimethylformamide (DMFA) mixture, 1.5-14 g of CuCl.sub.2.2H.sub.2O are put. The contents of the flask are mixed until copper chloride dissolves completely. a. Example 4. Gas purification involving catalyst C1. The gas is purified with use of the device and the process that are claimed as the current invention, but C1 known from (RU, patent No. 2405738, issued 27 Apr. 2010) is used as the catalyst. b. Non-aqueous organic solvent and catalyst C1 synthesized as in Example 1 are put into the reactor. The gas supplied into the reactor contains 0.1% vol. of hydrogen sulfide, 0.05% of mercaptan sulfur and 0.06% vol. of oxygen. The solution temperature is 25? C. The output gas contains, according to potentiometric titration results, 40 ppm and 50 ppm of hydrogen sulfide and mercaptan respectively. Conversion of hydrogen sulfide and mercaptan is 95.5 and 91% respectively. c. Thus the device and the process claimed as the current invention even with use of a known catalyst composition (known from RU, patent No. 2405738, issued 27 Apr. 2010) provide conversion rate of hydrogen sulfide and mercaptan into sulfur and disulfides not more than 95.5%.

(6) Example 5. Gas purification in accordance with current invention claim using catalyst C2. Non-aqueous organic solvent and catalyst C2 are put into the reactor. The gas supplied into the reactor contains 1% vol. of hydrogen sulfide, 0.05% SH and 0.5025% vol. of oxygen. The solution temperature is 25? C. The output gas contains, according to potentiometric titration results, 60 ppm of hydrogen sulfide and 60 ppm of mercaptan. Conversion of hydrogen sulfide and mercaptane is 99.4?88% respectively. a. Thus examples 4 and 5 illustrate that even using of non-optimal catalyst composition the device and process claimed as current invention provide hydrogen sulfide conversion of 95.5-99.4% and mercaptan conversion of 88-91%.

(7) Examples 6-14. Gas purification using catalyst C3 that utilizes the proposed process, catalyst and device.

(8) Non-aqueous organic solvent ant catalyst C3 with content of 0.001-100% are placed into the reactor. The gas supplied into the reactor contains 0.1-1.8% vol. of hydrogen sulfide, 0.05-0.5% of mercaptans and 0.075-1.15% vol. of oxygen. The solution temperature is 20-40? C. The output gas according to potentiometric titration contains 10-0.001 ppm of hydrogen sulfide and 0.001-20 ppm of mercaptans. The conversion of hydrogen sulfide is 99.8-99.9999%, of mercaptan98-99.9999%. The experiment results with use of different catalysts C1-C3 are shown in Table 1.

(9) TABLE-US-00001 TABLE 1 [H.sub.2S] [RSH] content, % mas. in, % out, in, % out, No catalyst amine + amide Cu + Fe vol. ppm vol ppm 4 C1 93 7 0.1 40 0.05 50 5 C2 56 44 1 60 0.05 60 6 C3 60 40 1 10 0.05 10 7 C3 70 30 1 10 0.05 10 8 C3 80 20 1.8 8 0.05 10 9 C3 85 15 0.5 4 0.05 10 10 C3 94 6 0.5 3 0.1 10 11 C3 93 7 1.0 2 0.5 4 12 C3 92 8 1.0 2 0.5 3 13 C3 91 9 1.0 0.01 0.5 0.01 14 C3 90 10 0.1 0.001 0.1 0.001

(10) In frame of current work, the following results were discovered:

(11) Using catalyst C1 with device and process claimed as current invention provide insufficient conversion of hydrogen sulfide and mercaptans, 95.5% and 91% respectively.

(12) Using catalyst C2 with device and process claimed as current invention provides not only desulfurization as in U.S. Pat. No. 2,398,735, issued 10 Sep. 2010, but also demercaptanization. Mercaptan conversion proves to be 88%.

(13) The catalyst proposed in current application catalyzed oxidation of both hydrogen sulfide and mercaptans with high degree of conversion, see Table 2.

(14) Conversion of hydrogen sulfide and mercaptans in Examples 6-14 is shown in Table 2.

(15) TABLE-US-00002 TABLE 2 No conversion, % 6 7 8 9 10 11 12 13 14 H.sub.2S 99.0 99.9 99.96 99.8 99.9 99.9 99.98 99.999 99.9999 RSH 98.0 98.0 98.0 98.0 99.8 99.9 99.9 99.99 99.9999

(16) Results of gas purification by proposed process and with proposed device and catalyst C3 with different ratio of amine/amide/transition metal are shown in Table 3. The conditions of experiment are similar to those of experiments No. 6-14.

(17) TABLE-US-00003 TABLE 3 [H.sub.2S] [RSH] Content, % mas. in, out, in, out, No catalyst amine amide metal % vol. ppm % vol. ppm 15 C3 89 10 1 1 10 0.1 10 16 C3 45 50 5 1 10 0.1 10 17 C3 40 50 10 1 4 0.1 6 18 C3 10 70 20 1 4 0.1 6

(18) Results of gas purification by proposed process and with proposed device and catalyst C3 in various solvents with ratio of amine/amide/transition metal=4:5:1 are shown in Table 4. The conditions of experiment are similar to those of experiments No. 6-14.

(19) TABLE-US-00004 TABLE 4 [H.sub.2S] [RSH] in, out, in, out, catalyst solvent % vol. ppm % vol. ppm C3 octane 1 4 0.1 6 C3 naphtha 1 10 0.1 10 C3 petrol 1 10 0.1 10

(20) Results of gas purification by proposed process and with proposed device, with different content of catalyst C3 are shown in Table 5. The conditions of experiment are similar to those of experiments No. 6-14.

(21) TABLE-US-00005 TABLE 5 [H.sub.2S] [RSH] No [C3], % vol. in, % vol. out, ppm in, % vol. out, ppm 19 0.001-0.5 1 10 0.1 12 20 1-5 1 4 0.1 6 21 10 1 0.001 0.1 0.01

(22) Results of gas purification where the gas has different content of methane, ethane, C.sub.3+ by proposed process and with proposed device and catalyst C3 are shown in Table 6. The conditions of experiment are similar to those of experiments No. 6-14.

(23) TABLE-US-00006 TABLE 6 content, [H.sub.2S] [RSH] % vol. in, out, in, out, No catalyst C.sub.1 C.sub.2 C.sub.3+ % vol. ppm % vol. ppm 22 C3 85 12 3 1 10 0.1 10 23 C3 74 22 4 1 10 0.1 10 24 C3 100 1 10 0.1 10 25 C3 95 5 1 4 0.1 5

(24) The examples provided confirm that the stated technical result is achieved, yet they do not show the limits of proposed technical solution.

(25) It will be understood that the system and method may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the system method is not to be limited to the details given herein.