Ni nano cluster support on MgO—CeO2—ZrO2 catalyst for tri-reforming of methane and a process for preparation thereof

Abstract

The present invention provides a Ni nano-cluster supported on MgOCeO.sub.2ZrO.sub.2 catalyst and processes the production of the catalyst. Further, the present invention discloses use of Ni nano-cluster supported on MgOCeO.sub.2ZrO.sub.2 catalyst for the synthesis gas (a mixture of CO and H.sub.2) by tri-reforming of methane. The process provides a direct single step selective vapor phase tri-reforming of methane to synthesis gas over NiOMgOCeO.sub.2ZrO.sub.2 oxide catalyst between temperature range of 600 C. to 800 C. at atmospheric pressure. The process provides a methane conversion of 1-99% with H.sub.2 to CO mole ratio of 1.6 to 2.3.

Claims

1. A nano NiMgCeZr oxide catalyst having a formula NiOMgOCeO.sub.2ZrO.sub.2 (NiO-MCZ) which comprises NiO in a range of 2.5-10 wt %, MgO in a range of 1-5 wt %, CeO.sub.2 in a range of 20-25 wt % and ZrO.sub.2 in a range of 60-72.5 wt %.

2. The catalyst as recited in claim 1, having a particle size of 5-10 nm.

3. The catalyst as recited in claim 1, wherein the wt % ratio of Ni and MCZ is in range of 2.5:97.5-10:90.

4. A process for the preparation of nano NiMgCeZr oxide catalyst as recited in claim 1, wherein said process comprises the steps of: a) stirring zirconium salt with ethanol for a period ranging between 1-2 hours at a temperature ranging between 25-35 C.; b) preparing a second solution by stirring a surfactant and ethanol for a period ranging between 1-2 hours at a temperature ranging between 25-30 C. subsequently adding magnesium salt and cerium salt and ethanol during continuous stirring and covering with paraffin film and stirring at a temperature ranging between 25-35 C. for a period ranging between 10-14 hours; c) mixing both solutions as prepared in step (a) and step (b) and stirring for 7-8 hours at a temperature ranging between 25-35 C. followed by drying at temp a temperature ranging between 50-70 C. and calcining at a temperature ranging between 400 C.-600 C. for a period ranging between 5-7 hours to obtain a magnesium-cerium-zirconium oxide support; d) preparing an aqueous solution of nickel salt with stirring for a period ranging between 1-2 hours at a temperature ranging between 25-30 C. and adding the magnesium-cerium-zirconium oxide support as obtained in step (c) into it; e) preparing a separate solution of urea in water with stirring for a period ranging between 1-2 hours at a temperature ranging between 25-30 C.; and f) mixing both solutions as obtained in step (d) and (e) with stirring for a period ranging between 10-14 hours at a temperature ranging between 25-30 C., subsequently setting the temperature at 70-100 C. followed by cooling after 24-48 hours and filtering and calcining at a temperature ranging between 400 C.-600 C. for a period ranging between 5-7 hours to obtain nano NiMgCeZr oxide catalyst.

5. The process as recited in claim 4, wherein Zr the zirconium salt used in step (a) is zirconium isopropoxide.

6. The process as recited in claim 4, wherein the magnesium and cerium salt used in step (b) are magnesium nitrate hexahydrate and cerium nitrate hexahydrate, respectively.

7. The process as recited in claim 4, wherein the surfactant used in step (b) is P123 (Pluronic acid).

8. The process as recited in claim 4, wherein the nickel salt used in step (d) is nickel nitrate.

9. The process as recited in claim 4, wherein the wt % ratio of Ni and MCZ is in range of 2.5:97.5-10:90.

10. The process as recited in claim 4, wherein the mole ratio of zirconium salt, cerium salt and magnesium salt is in a range of 23:5:6 to 25:6:7.

11. A process for production of methane using nano NiMgCeZr oxide catalyst to obtain syngas, wherein said process comprises passing an O.sub.2:CO.sub.2:H.sub.2O:CH.sub.4:He mixture with a molar ratio of 1:1:1.7:5:18 to 1:1:2.4:5:18 in a reactor at atmospheric pressure in the presence of a nano NiMgCeZr oxide catalyst at a temperature ranging between 600-800 C. for a period ranging between 1-100 hours at a gas hourly space velocity (GSHV) ranging between 20,000-200,000 mlg.sup.1h.sup.1 to obtain syngas.

12. The process as claimed in claim 11, wherein the process produces a H.sub.2/CO ratio 2.

13. The process as claimed in claim 11, wherein the conversion of methane is in a range of 50-99% over 5-10 nm catalyst particles.

14. The process as claimed in claim 11, wherein a H.sub.2/CO ratio of syngas obtained in a range of 1.6-2.3 over 5-10 nm catalyst particles.

Description

BRIEF DESCRIPTION OF DRAWING

(1) FIG. 1 X-ray Diffraction (XRD) of 2.5% Ni-MCZ.

(2) FIG. 2 Scanning Electron Microscope (SEM) image of 2.5% Ni-MCZ.

(3) FIG. 3 TEM image of 2.5% Ni-MCZ.

(4) FIG. 4 (a) Mapping of Ni in 2.5% Ni-MCZ; (b) Mapping of Mg in 2.5% Ni-MCZ; (c) Mapping of Ce in 2.5% Ni-MCZ; (d) Mapping of Zr in 2.5% Ni-MCZ.

(5) FIG. 5 X-ray Diffraction (XRD) of 5% Ni-MCZ.

(6) FIG. 6 SEM image of 5% Ni-MCZ.

(7) FIG. 7 TEM image of 5% Ni-MCZ.

(8) FIG. 8 (a) Mapping of Ni in 5% Ni-MCZ; (b) Mapping of Mg in 5% Ni-MCZ; (c) Mapping of Ce in 5% Ni-MCZ; (d) Mapping of Zr in 5% Ni-MCZ.

(9) FIG. 9 (a) TPR of 2.5% Ni-MCZ; (b) TPR of 5% Ni-MCZ.

DETAILED DESCRIPTION OF THE INVENTION

(10) The present invention provides a nanoNiMgCeZr oxide catalyst having formula NiOMgOCeO.sub.2ZrO.sub.2 comprises NiO in the range of 2.5-10 wt %, MgO in the range of range 1-5 wt %, CeO.sub.2 in the range of 20-25 wt % and ZrO.sub.2 in the range of 60-72.5 wt % with particle size of the catalyst is in the range of 5-10 nm.

(11) The present invention provides a process for the preparation of Ni-MCZ to produce synthesis gas by Tri-reforming of methane involves the following steps.

(12) The process for the preparation of Ni nano-cluster supported MgOCeO.sub.2ZrO.sub.2 catalyst comprising the steps of: a) Synthesis of Ni-MCZ was carried out using organic matrix decomposition method. b) Zirconium isopropoxide, magnesium nitrate hexahydrate, cerium nitrate hexahydrate, nickel nitrate hexahydrate, P123 (Pluronic acid), urea, ethanol, H.sub.2O were used for the synthesis where the metal nitrate salts were used as the respective precursors. c) The molar ratio of Zirconium isopropoxide to ethanol was varied in the range of 1:57. d) The molar ratio of P123 to ethanol was varied in the range of 1:950. e) After adding magnesium nitrate and cerium nitrate to the above mixture the solution was left for stirring 8-14 hrs. f) Mixture of all the solution was stirred for 7-8 hrs. g) The whole mixture was dried at 60 C. h) The dried mixture was calcined at 400 C. for 5-8 hrs.

(13) Loading of Ni on Support: a) Taken 750 ml of H.sub.2O in a beaker and added 0.37 g to 1.48 g of Nickel nitrate. b) Continued stirring for 1 hr. c) In another beaker taken 750 ml of H.sub.2O and add 0.25 gm to 1 gm of urea in this beaker. d) Continued stirring for 1 hr. e) In first beaker added 3 gm support and mixed both solutions. f) Continued stirring for 1 hr. g) The temperature was raised to 90 C. and kept for 48 hrs. h) Cooled to room temperature calcined at 400 C. for 5-8 hrs.

EXAMPLES

(14) The following examples are given by way of illustration of working of the invention in actual practice and should not be constructed to limit the scope of the present invention in any way.

(15) General Procedure for the Tri-Reforming of Methane to Synthesis Gas

(16) The Tri-reforming of methane was carried out in a fixed-bed down flow reactor at atmospheric pressure. Typically 10 to 500 mg of catalyst was placed in between two quartz wool plugged in the center of the 6 mm quartz reactor. The reaction was carried out with the freshly prepared catalyst at different temperatures ranging 600-800 C. The flow of feed gasses are controlled by mass flow controllers. The gas hourly space velocity (GHSV) was varied between 20000 to 200000 ml g-1 h-1 with a molar ratio of O2:CO2:H2O:CH4:He of 1:1:1.8:5:18 to 1:1:2.4:8:18. The reaction products were analyzed using an online gas chromatography (Agilent 7890A) fitted with a TCD detector using two different columns Molecular sieves (for analyzing H2) and PoraPack-Q (for analyzing CH4, CO2 and CO).

Example-1

Preparation of MCZ

(17) 7.54 g zirconium isopropoxide was taken in beaker and 50 ml ethanol was added and kept for stirring after covering it with paraffin film at temperature 30 C. for a period 1 hr. In another beaker 4.1 g P123 (Pluronic acid) was taken and 30 ml ethanol was added and kept for stirring at temperature 30 C. for a period 1 h. 1.58 g Magnesium Nitrate and 2.32 g Cerium Nitrate was added during continuous stirring. And 20 ml ethanol was added and covered with paraffin film and left for stirring 12 h at temperature 30 C. Both solutions were mixed in one beaker. After about 7 hrs of stirring, it was left for drying at 60 C. for 48 h and calcined at 400 C. for 5 hrs.

(18) Preparation of 2.5% Ni-MCZ:

(19) Taken 750 ml of H.sub.2O in a beaker and added 0.37 g of Nickel nitrate in it and kept on stirring for 1 hr at 30 C. In another beaker taken 750 ml of H.sub.2O and add 0.25 g of urea in this beaker and kept it on stirring for 1 hr at 30 C. In first beaker added 3 gm support and mixed both solutions. After 1 hr of stirring at temp 30 C., set the temperature at 90 C. After 48 hrs it was cooled and filtered and calcined at 400 C. for 5 hrs.

(20) The materials were characterized by XRD, SEM, elemental mapping and TEM.

(21) The XRD pattern of the 2.5% Ni-MCZ is shown in FIG. 1. XRD depicts the presence of Ni nitrate, MgO2, CeO.sub.2 and ZrO.sub.2 in the sample. The morphology of the material (2.5% Ni-MCZ) was characterized by SEM. The typical image of the 2.5% Ni-MCZ is shown in FIG. 2. From the SEM image it is clear that the particles are almost spherical in shape. The typical TEM images of the 2.5% Ni-MCZ are shown in FIG. 3. The dispersion of the Ni particles on MCZ support was analyzed by taking the elemental mapping of Ni, Mg, Ce, and Zr using SEM as shown in FIG. 5(a,b,c,d) respectively. The mapping confirms that Ni is highly dispersed on MCZ. FIG. 9 represents the TPR profile (a) of the catalyst 5% Ni-MCZ. The catalyst contains 2.5 wt. % NiO, 1 wt. % MgO, 20 wt. % CeO.sub.2, 76.5 wt. % ZrO.sub.2.

Example-2

Preparation of MCZ

(22) 7.54 g zirconium isopropoxide was taken in beaker and 50 ml ethanol was added and kept for stirring after covering it with paraffin film at temperature 30 C. for a period 1 hr. In another beaker 4.1 g P123 (Pluronic acid) was taken and 30 ml ethanol was added and kept for stirring at temperature 30 C. for a period 1 h. 1.58 g Magnesium Nitrate and 2.32 g Cerium Nitrate was added during continuous stirring. And 20 ml ethanol was added and covered with paraffin film and left for stirring 12 hrs at temperature 30 C. Both solutions were mixed in one beaker and after 7 hrs of stirring, it was left for drying at 60 C. for 48 h and calcined at 400 C. for 5 hrs.

(23) Preparation of 5% Ni-MCZ:

(24) Taken 750 ml of H.sub.2O in a beaker and added 0.74 g of Nickel nitrate in it and kept on stirring for 1 hr at 30 C. In another beaker taken 750 ml of H.sub.2O and add 0.46 g of urea in this beaker and kept it on stirring for 1 hr at 30 C. In first beaker added 3 gm support and mixed both solutions. After 1 hr of stirring at temp 30 C., set the temperature at 90 C. After 48 hrs it was cooled and filtered and calcined at 400 C. time 5 hrs.

(25) The materials were characterized by XRD, SEM, elemental mapping and TEM.

(26) The XRD pattern of the 5% Ni-MCZ is shown in FIG. 5. XRD depicts the presence of Ni nitrate, MgO.sub.2, CeO.sub.2 and ZrO.sub.2 in the sample. The morphology of the material (5% Ni-MCZ) was characterized by SEM. The typical image of the 5% Ni-MCZ is shown in FIG. 6. From the SEM image it is clear that the particles are almost spherical in shape. The typical TEM images of the 5% Ni-MCZ are shown in FIG. 7. The dispersion of the Ni particles on MCZ support was analyzed by taking the elemental mapping of Ni, Mg, Ce, and Zr using SEM as shown in FIG. 8 (a,b,c,d), respectively. The mapping confirms that Ni is highly dispersed on MCZ. FIG. 9 represents the TPR profile (b) of the catalyst 5% Ni-MCZ. The catalyst contains 5 wt. % NiO, 1 wt. % MgO, 20 wt. % CeO.sub.2, 74 wt. % ZrO.sub.2.

Example-3

(27) The example describes the effect of temperature on conversion and H.sub.2/CO ratio of partial oxidation of methane. The product analysis presented in Table 1.

(28) Process Conditions:

(29) Catalyst: 0.24 g Ni:MCZ weight ratio in the catalyst=2.5:97.5 Process pressure: 1 atm. Gas hourly space velocity (GHSV): 20000 ml g.sup.1 h.sup.1 Reaction time: 4 hrs O.sub.2:CO.sub.2:H.sub.2O:CH.sub.4:He=1:1:2:5:18 (mol %)

(30) TABLE-US-00001 TABLE 1 Effect of temperature on conversion Methane CO.sub.2 Temperature Conversion Conversion H.sub.2O Syngas ( C.) (%) (%) Conversion (%) H.sub.2/CO ratio 600 71.69 11.53 59.10 2.3 700 91.29 70.06 90.15 2.2 800 98.32 89.76 94.99 2.0

Example-4

(31) The example describes the effect of temperature on the conversion of methane and H.sub.2/CO ratio of partial oxidation of methane. The product analysis presented in Table 2.

(32) Process Conditions:

(33) Catalyst: 0.060 g Ni:MCZ weight ratio in the catalyst=2.5:97.5 Process pressure: 1 atm Gas hourly space velocity (GHSV): 80000 ml g.sup.1 h.sup.1 Temperature: 600-800 C. Reaction time: 4 hrs O.sub.2:CO.sub.2:H.sub.2O:CH.sub.4:He=1:1:2:5:18 (mol %)

(34) TABLE-US-00002 TABLE 2 Effect of temperature on conversion Methane CO.sub.2 Temperature Conversion Conversion H.sub.2O Syngas ( C.) (%) (%) Conversion (%) H.sub.2/CO ratio 600 67.56 41.53 59.96 2.2 700 89.46 72.36 88.15 2.1 800 96.32 94.01 93.8 2.1

Example-5

(35) The example describes the effect of gas hourly space velocity on the conversion of methane and H.sub.2/CO ratio of partial oxidation of methane. The product analysis presented in Table 3.

(36) Process Conditions:

(37) Catalyst: 0.030 g Ni:MCZ weight ratio in the catalyst=2.5:97.5 Process pressure: 1 atm Temperature: 800 C. Reaction time: 4 hrs O.sub.2:CO.sub.2:H.sub.2O:CH.sub.4:He=1:1:2:5:18 (mol %)

(38) TABLE-US-00003 TABLE 3 Effect of gas hourly space velocity (GHSV) on the conversion of methane and H.sub.2/CO ratio of partial oxidation of methane GHSV Methane (ml feed/ Conversion CO.sub.2 H.sub.2O Syngas h/g.sub.cat) (%) Conversion (%) Conversion (%) H.sub.2/CO ratio 20000 98.32 89.76 94.99 2.1 50000 93.78 86.67 89.26 2.1 100000 88.65 84.86 85.69 2.1 200000 68.80 61.79 64.39 2.1

Example-6

(39) The example describes the effect of time on stream on conversion of methane and H.sub.2/CO ratio of dry reforming of methane. The product analysis presented in Table 4

(40) Process Conditions:

(41) Catalyst: 0.06 g Ni:MCZ weight ratio in the catalyst=2.5:97.5 Process pressure: 1 atm Gas hourly space velocity (GHSV): 80000 ml g.sup.1 h.sup.1 Reaction temperature: 800 C. O.sub.2:CO.sub.2:H.sub.2O:CH.sub.4:He=1:1:2:5:18 (mol %)

(42) TABLE-US-00004 TABLE 4 Methane Conversion CO.sub.2 H.sub.2O Time (h) (%) Conversion (%) Conversion (%) 0 95.52 94.41 96.32 1 96.45 92.14 95.69 2 95.99 92.48 96.17 4 96.54 90.15 94.73 6 98.50 91.14 95.30 8 98.62 92.73 95.49 10 99.31 92.90 94.83 15 96.48 93.19 94.48 20 96.47 93.46 95.11 25 97.33 91.04 95.49 30 96.30 94.01 96.50 40 95.80 94.62 95.69 50 96.30 94.14 95.40 60 94.52 94.13 96.76 70 96.16 94.12 95.68 80 95.96 94.52 95.56 90 97.52 90.16 95.29 100 97.51 90.44 95.51

Advantages of the Present Invention

(43) The main advantages of the present invention are: a) The process of the present invention is to utilize methane by converting methane to syngas through Tri-reforming of methane in a single step with a single catalyst. b) The process of the present invention is to utilize carbon dioxide to produce syngas through Tri-reforming of methane in a single step with a single catalyst. c) The process of the present invention is to utilize steam by to produce syngas through Tri-reforming of methane in a single step with a single catalyst. d) The process provides not only good conversion but also good H.sub.2/CO ratio of syngas. e) The process utilizes a major component of abandoned new fuel resources to produce syngas with H.sub.2/CO ratio almost equal to two, which become the major advantages of this process and which can be directly use for the production of methanol and Fischer-Tropsch synthesis. f) The process utilizes three greenhouse gasses to produce synthesis gas. g) The process does not produce any major by-products which is also a major advantage of this process. h) The catalyst shows no deactivation up to 100 h time on stream at 800 C.; i) The catalyst is used in very low amounts.