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

Abstract

This application is in the field of technologies for desulfurization and demercaptanization of raw gaseous hydrocarbons (including natural gas, tail gas, technological gas, etc, including gaseous media). It can be used for simultaneous dehydration and desulfurization/demercaptanization of any kind of raw gaseous hydrocarbons.

Claims

1. A process of desulfurization and/or demercaptanization and/or dehydration of gaseous hydrocarbons, comprising: mixing one or more gaseous hydrocarbons comprising an initial amount of hydrogen sulfide, mercaptans, and water, to be purified with an oxygen-containing gas, pressurizing and passing through a reactor loaded with a solution of a catalyst for oxidating the hydrogen sulfide and mercaptans in an absorbent that also provides for dehydration of said gaseous hydrocarbons, maintaining a gas pressure, as determined by a desired content of water in purified gas thereby simultaneously dehydrating the gaseous hydrocarbons, wherein the catalyst comprises mixed-ligand complexes of transition metals, wherein the catalyst comprises an amine, dimethylformamide (DMF), and CuCl.sub.2*2H.sub.2O, and producing an end product having a residual mercaptan concentration of 10 ppm or less and a residual hydrogen sulfide concentration of 10 ppm or less.

2. The process of claim 1, wherein an amount of oxygen is at least 50% of the total initial amount of hydrogen sulfide and mercaptan sulfur.

3. The process of claim 1, wherein the gaseous hydrocarbons that are supplied into the reactor are distributed evenly within the reactor.

4. The process of claim 1, wherein the catalyst is supplied into the reactor by a metered supply unit.

5. The process of claim 1, further comprising: separating sulfur from a suspension, and recycling the catalyst into the reactor.

6. The process of claim 1, wherein the absorbent comprises glycols or mixtures of glycols with organic compounds.

7. The process of claim 1, wherein a pressure and a temperature of the reactor is maintained in a desired range to provide a required rate of dehydration of the gaseous hydrocarbons.

8. The process of claim 1, wherein the catalyst comprises mixed-ligand complexes based on ferric and/or cupric halogenides with an addition of one or more solvating agents.

9. The process of claim 1, wherein the gas pressure is up to 6 kgf/cm.sup.2.

10. The process of claim 1, wherein the gas pressure is 25 kgf/cm.sup.2.

11. The process of claim 1, wherein the gas pressure is 60 kgf/cm.sup.2.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows the block diagram of the proposed device in the preferred embodiment where the following notations are used: pipeline 1 that supplies the raw gas 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, desulfurization/demercaptanization/dehydration reactor 6, means 7 of distribution of mixture of hydrocarbon gas and oxygen-containing gas in the volume of reactor 6, tank 8 containing catalyst solution, agitator 9 of 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 reactor 6 after sulfur has been separated, agitator 16 of catalyst solution recycling from sulfur-separating unit 13 into 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 loaded with a solution of a catalyst in an absorbent18, 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 unita regular pump can be used.

(4) Below, the essence and advantages of the developed technical solution are discussed in examples of practical implementation.

(5) Example 1. Synthesis of catalyst C1. Into a retort, at a room temperature, 50 ml of ethyl alcohol, 100 ml of octane, 0.2-10 g of CuCl.sub.2.2H.sub.2O and 0.5-50 g of benzylamine are put. The contents of the retort are mixed until cupric chloride dissolves completely.

(6) Example 2. Synthesis of catalyst C2. Into a retort, at a room temperature, 50 ml of ethyl alcohol, 100 ml of octane, 0.2-10 g of CuCl.sub.2.2H.sub.2O and 0.5-50 g of cyclohexamine are put. The contents of the retort are mixed until cupric chloride dissolves completely.

(7) Example 3. Synthesis of catalyst C3. Into a retort, at a room temperature, 50 ml of ethyl alcohol, 100 ml of octane, 0.2-10 g of

(8) CuCl.sub.2.2H.sub.2O and 0.5-50 g of pyridine are put. The contents of the retort are mixed until cupric chloride dissolves completely.

(9) Example 4. Synthesis of catalyst C4. Into a retort, at a room temperature, 50 ml of ethyl alcohol, 20 ml of water, 0.2-60 g of dimethylformamide (DMFA), and 0.2-10 g of CuCl.sub.2.2H.sub.2O are put. The contents of the flask are mixed by means of a magnetic mixer until cupric chloride dissolves completely.

(10) Example 5. Synthesis of catalyst C5. Into a retort, at a room temperature, 50 ml of alcohol, 0.2-60 g of mixture of amine (cyclohexamine, pyridine) with dimethylformamide (DMFA), 0.2-10 g of CuCl.sub.2.2H.sub.2O are put. The contents of the flask are mixed until cupric chloride dissolves completely.

(11) Examples 6-27. Gas purification using catalysts C1-05. The reactor is loaded with glycol and one of the catalysts C1-05 synthesized as in examples 1-5, respectively. The gas supplied into the reactor contains 1%-2.2% vol. of hydrogen sulfide, 0.05% of mercaptan sulfur and 0.5025%-1.125% vol. of oxygen. The gas pressure is 2.5-60 kgf/cm.sup.2. The solution temperature is 25-40 C. The output gas contains, according to potentiometric titration results, 0.001 ppm-70 ppm of hydrogen sulfide and mercaptan.

(12) The rate of hydrogen sulfide removal is 99.6%-99.99999%, the rate of mercaptan removal is up to 99.998%. The rate of dehydration is determined by the gas pressure. The higher the gas pressure is, the lower amount of water remains in the output gas.

(13) Experimental data on hydrogen sulfide, mercaptan and water contents after desulfurization/demercaptanization/dehydration of the gas using catalyst C1 is given in Table 1.

(14) TABLE-US-00001 TABLE 1 [H.sub.2S] [RSH] Example T, Input, Output, Input, Output, [H.sub.2O], g/m.sup.3 No C. % vol. ppm % vol. ppm Input Output Gas pressure 6 kgf/cm.sup.2 6 25 1.5 40 0.05 50 3.584 0.424 7 40 1.5 60 0.05 60 8.284 0.939 Gas pressure 25 kgf/cm.sup.2 8 25 1.5 45 0.05 60 1.069 0.135 9 40 1.5 45 0.05 60 2.425 0.291

(15) Experimental data on hydrogen sulfide, mercaptan and water contents after desulfurization/demercaptanization/dehydration of the gas using catalyst C2 at temperature 25-40 C. and under different conditions is given in Table 2.

(16) TABLE-US-00002 TABLE 2 [H.sub.2S] [RSH] Example T, Input, Output, Input, Output, [H.sub.2O], g/m.sup.3 No C. % vol. ppm % vol. ppm Input Output Gas pressure 6 kgf/cm.sup.2 10 25 1.5 40 0.05 50 3.584 0.424 11 40 1.5 50 0.05 60 8.284 0.939 Gas pressure 25 kgf/cm.sup.2 12 25 1.5 45 0.05 60 1.069 0.135 13 40 1.5 45 0.05 60 2.425 0.291

(17) Experimental data given in Tables 1 and 2 show that the proposed device and process is capable of achieving the stated technical result even if the catalyst composition used is not optimal.

(18) Experimental data on hydrogen sulfide, mercaptan and water contents after desulfurization/demercaptanization/dehydration of the gas using catalysts C1, C2, C3 at temperature 25-40 C. and under different conditions is given in Table 3.

(19) TABLE-US-00003 TABLE 3 [H.sub.2S] [RSH] Example T, Input, Output, Input, Output, [H.sub.2O], g/m3 No C. % vol. ppm % vol. ppm Input Output Gas pressure 6 kgf/cm.sup.2 14 25 1.5 50 0.05 60 3.584 0.424 15 40 1.5 60 0.05 70 8.284 0.939 Gas pressure 25 kgf/cm.sup.2 16 25 1.5 45 0.05 60 1.069 0.135 17 40 1.5 45 0.05 60 2.425 0.291

(20) Experimental data on hydrogen sulfide, mercaptan and water contents after desulfurization/demercaptanization/dehydration of the gas using catalyst C4 at temperature 25-40 C. and under different pressure is given in Table 4.

(21) TABLE-US-00004 TABLE 4 [H.sub.2S] [RSH] Example T, Input, Output, Input, Output, [H.sub.2O], g/m3 No C. % vol. ppm % vol. ppm Input Output Gas pressure 6 kgf/cm.sup.2 18 25 1.5 40 0.05 50 3.584 0.424 19 40 1.5 45 0.05 50 8.284 0.939 Gas pressure 25 kgf/cm.sup.2 20 25 1.5 40 0.05 60 1.069 0.135 21 40 1.5 40 0.05 60 2.425 0.291

(22) Experimental data on hydrogen sulfide, mercaptan and water (g/m.sup.3 and T.sub.dew point, C., water dew point temperature at P=3.92 MPa) contents after desulfurization/demercaptanization/dehydration of the gas using catalyst C5 at temperature 25-40 C. and under different pressure is given in Table 5.

(23) TABLE-US-00005 TABLE 5 Exam- [H.sub.2S] [RSH] [H.sub.2O] in output ple T, Input, Output, Input, Output, T.sub.dew point, No C. % vol. ppm % vol. ppm g/m.sup.3 C. Gas pressure 2.5 kgf/cm.sup.2 22 25 1.5 4 0.05 5 0.817 27 Gas pressure 6 kgf/cm.sup.2 23 25 1.5 4 0.05 5 0.424 15.0 24 40 1.8 7 0.05 7 0.939 29.0 Gas pressure 25 kgf/cm.sup.2 25 25 1.5 0.001 0.05 0.01 0.135 2.0 26 40 2.2 2 0.05 4 0.291 9.0 Gas pressure 60 kgf/cm.sup.2 27 25 2.2 0.001 0.05 0.01 0.074 10.0

(24) Hydrogen sulfide and mercaptan conversion in Examples 6-27 is given in Table 6.

(25) TABLE-US-00006 TABLE 6 Example No Conversion, % 6 7 8 9 22 23 24 25 26 27 H.sub.2S 99.7 99.6 99.7 99.7 99.97 99.97 99.96 99.9999 99.991 99.9999 RSH 90.0 90.0 88.0 88.0 99.0 99.0 98.6 99.998 99.2 99.998

(26) The examples provided show efficiency of the proposed device and process of hydrogen sulfide and mercaptans conversion. The amount of remaining water after dehydration therein is determined by process pressure and temperature, as is demonstrated in Tables 1-5. Under pressure 60 kgf/cm.sup.2 the water content in the gas is reduced to 0.074 g/m.sup.3, that corresponds to water dew point of 10 C.

(27) Table 7 shows the results of gas purification by means of the proposed device and process with different concentration of catalyst C5. The conditions of the experiment are similar to those of experiments No. 6-27, temperature is 25 C.

(28) TABLE-US-00007 TABLE 7 [H.sub.2O] in P, [H.sub.2S] [RSH] output [C5], % kgf/ Input, Output, Input, Output, T.sub.dew point, vol. cm.sup.2 % vol. ppm % vol. ppm g/m.sup.3 C. 0.005 6 1 10 0.1 10 0.42 15 0.005 25 1 10 0.1 10 0.14 2 0.3 60 1 10 0.1 10 0.07 10

(29) Table 8 shows results of purification and dehydration of gas having different hydrocarbon composition, with different contents of methane, C.sub.1, ethane, C.sub.2, and C.sub.3+ by proposed device and process, using catalyst K5. The conditions of experiments are similar to those of experiments No. 6-27.

(30) TABLE-US-00008 TABLE 8 [H.sub.2O], in [H.sub.2S] [RSH] output Content, % vol. P, Input, Output, Input, Output, T.sub.dew point, C.sub.1 C.sub.2 C.sub.3+ kgf/cm.sup.2 % vol. ppm % vol. ppm g/m.sup.3 C. 85 12 3 6 1 10 0.1 10 0.42 15 74 22 4 25 1 10 0.1 10 0.14 2 100 25 1 10 0.1 10 0.14 2 95 5 60 1 4 0.1 5 0.07 10

(31) The examples provided confirm achievement of the stated technical result, yet they do not show the limits of proposed technical solution.

(32) 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.