Hydrogen production by methanol steam reforming based on electromagnetic induction heating

Abstract

The application discloses a methanol steam reforming hydrogen production method based on electromagnetic induction heating. A catalyst bed is arranged in a reactor, a magnetic conductive material layer is arranged close to the outer wall of the reactor, a spiral coil is arranged around the magnetic conductive material layer, the spiral coil is communicated with a high-frequency power supply, and induction heating is carried out by electrification. When the temperature in the reactor is 200-220 DEG C, methanol and water vapor are input into the inlet of the reactor, a reaction occurs, hydrogen is generated, and the hydrogen is discharged from the outlet of the reactor. The component of the magnetic conductive material layer is nano tin-cobalt alloy modified high-entropy ceramic powder, and the component of the catalyst bed is potassium modified carbon fiber loaded zinc-chromium spinel.

Claims

1. A method for hydrogen production by methanol steam reforming based on electromagnetic induction heating, characterized by, A catalyst bed is set inside the reactor, and a magnetic material layer is set in close contact with the outer wall of the reactor. A spiral coil is set around the magnetic material layer and connected to a high-frequency power supply for induction heating. When the temperature inside the reactor is 200-220°C, methanol and water vapor are introduced into the reactor inlet, and a reaction occurs to generate hydrogen gas, which is discharged from the reactor outlet. The magnetic material layer is composed of nano-scale tin-cobalt alloy modified high-entropy ceramic powder, and the catalyst bed is composed of potassium-modified carbon fiber supported zinc-chromium spinel. The high-entropy ceramic powder is (MgCoNiCuZn)O with a particle size of 20-30 μm. The nanoscale tin-cobalt alloy-modified high-entropy ceramic powder was prepared by the following method: (A) First, sodium borohydride is uniformly dispersed in diethylene glycol to obtain a sodium borohydride solution; then, tin chloride and cobalt chloride are uniformly dispersed in diethylene glycol to obtain a metal ion solution. (B) The high-entropy ceramic powder is then pretreated with poly(propyleneamine hydrochloride) to obtain pretreated high-entropy ceramic powder; (C) Then the pretreated high-entropy ceramic powder is ultrasonically dispersed in a sodium borohydride diethylene glycol solution and heated to 90-100°C under argon protection to obtain a premixed solution; (D) Finally, under the conditions of heat preservation and stirring, the metal ion solution is added to the premixed solution, heated and stirred to react, and then post-processed to obtain the final product. The potassium-modified carbon fiber-supported zinc-chromium spinel was prepared by the following method: (a) Prepare a solution containing shale tar, add zinc nitrate, chromium nitrate and urea, stir and mix well to obtain a precursor solution; (b) Electrospinning; (c) Pre-oxidation and carbonization to obtain carbon fiber-supported zinc-chromium spinel; (d) Potassium modification.

2. The method according to claim 1, characterized in that, The current frequency of the induction heating is 10-100 kHz, and the power density is 5-20 W / cm 3 .

3. The method according to claim 1, characterized in that, The molar ratio of methanol and water vapor is 1:1.1-1.2, the methanol liquid phase volume space velocity is 7000-8000 h -1 .

4. The method according to claim 1, characterized in that, The magnetic material layer is obtained by uniformly spraying nano-sized tin-cobalt alloy modified high-entropy ceramic powder onto the outer wall of the reactor using plasma spraying. The plasma spraying process conditions are: arc current 500-520V, spraying distance 110mm, powder feeding rate 20-25g / min, hydrogen pressure 0.6-0.8MPa, hydrogen flow rate 40-50L / h, argon pressure 1.2-1.5MPa, argon flow rate 1500-1600L / h; the thickness of the magnetic material layer is 500-600μm.

5. The method according to claim 1, characterized in that, The mass ratio of pretreated high-entropy ceramic powder to tin chloride is 1:3-4, the molar ratio of sodium borohydride, tin chloride, and cobalt chloride is 3-4:0.5-0.7:0.8-1, the concentration of sodium borohydride solution is 0.8-1 mol / L, and the concentration of metal ion solution is 4-5 mol / L.

6. The method according to claim 1, characterized in that, The specific method of step (B) is as follows: First, the high-entropy ceramic powder is ultrasonically dispersed in a 3-5 mol / L sodium chloride aqueous solution. Then, a 10-15% (w / w) poly(acrylamine hydrochloride) aqueous solution is added, stirred and mixed, centrifuged to collect the precipitate, and washed with water. The mass ratio of the high-entropy ceramic powder, sodium chloride aqueous solution, and poly(acrylamine hydrochloride) aqueous solution is 1:5-6:8-10, and the number average molecular weight of poly(acrylamine hydrochloride) is 100,000-150,000. In step (D), the heating and stirring reaction conditions are: 180-200℃ for 30-40 minutes with stirring. In step (D), the post-processing includes: naturally cooling to room temperature, adding an equal volume of anhydrous ethanol, centrifuging to collect the precipitate, and drying.

7. The method according to claim 1, characterized in that, In step (a), the solution containing shale tar is prepared by the following method: first, polyvinylpyrrolidone is added to N,N-dimethylformamide and stirred at 60-70°C for 8-10 hours; then, shale tar is added, and the mixture is kept warm and stirred until homogeneous; finally, toluene is added dropwise, and the mixture is kept warm and stirred for 6-8 hours. The ratio of polyvinylpyrrolidone, N,N-dimethylformamide, shale tar, and toluene is 1g:8-10mL:0.8-1g:1mL. The ratio of the solution containing shale tar, zinc nitrate, chromium nitrate, and urea is 40–42 mL: 1 mmol: 2 mmol: 20–22 mmol.

8. The method according to claim 1, characterized in that, In step (b), the electrospinning conditions are as follows: needle inner diameter 0.3–0.4 mm, feed rate 0.0006–0.0007 mm / s, voltage 18–20 V, spinning distance 18–20 cm, spinning temperature 30–35 °C, and relative humidity 50–60%. In step (c), the pre-oxidation conditions are: air flow rate of 80-100 mL / min, temperature increase to 300-320℃ at 2-3℃ / min, and pre-oxidation at this temperature for 2-3 hours; Carbonization conditions are: nitrogen flow rate 60-70 mL / min, temperature increased to 900-930℃ at 8-10℃ / min, carbonization for 2-3 hours; In step (d), the specific method for potassium modification is as follows: potassium nitrate is dispersed in 0.8-1 mol / L acetic acid solution, followed by the addition of carbon fiber-supported zinc chromium spinel. The mixture is stirred at room temperature for 5-6 hours, drained, and then calcined at 400-450℃ for 3-4 hours in air. The ratio of potassium nitrate, acetic acid solution, and carbon fiber-supported zinc chromium spinel is 0.3-0.5 g: 5-7 mL: 1-1.2 g.

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