Ammonia decomposition reactor and method using liquid metal as catalyst

Abstract

The invention discloses an ammonia decomposition reactor taking liquid metal as a catalyst, and relates to the technical field of ammonia decomposition hydrogen production. The reactor comprises liquid metal, a porous metal tube and a reaction cavity. In practical application, after the reactor is heated, ammonia gas is introduced from the porous metal tube, the ammonia gas is distributed and introduced through the porous metal tube, and the ammonia gas is decomposed into hydrogen and nitrogen under the catalytic action of liquid metal. High temperature is needed for industrial ammonia decomposition, the reactor adopts liquid metal as a catalyst, ammonia gas is distributed and fed through the porous metal pipe, the contact area of reaction gas and the liquid metal is enlarged, the reaction efficiency is improved, and the reaction temperature is reduced.

Description

Background Art

[0001] The invention belongs to the technical field of hydrogen production by decomposing ammonia, and in particular relates to a gallium-copper liquid metal ammonia decomposition reactor technology. Technical Field

[0002] In hydrogen production technology, ammonia, as an efficient hydrogen storage medium, has the advantages of easy liquefaction, storage and transportation, high safety and zero carbon emissions. The general ammonia decomposition reaction temperature is above 600°C, and high temperature has certain limitations on application. Using the catalytic properties of liquid metal for ammonia decomposition reaction can greatly reduce the reaction temperature. In addition, since the reaction gas and the liquid metal catalyst belong to two phases, the reaction gas uses a gas distributor with a microporous structure to introduce ammonia into the liquid metal, which greatly increases the contact area between the reaction gas and the liquid metal and improves the reaction efficiency. Summary of the invention

[0003] The purpose of the present invention is to provide a liquid metal ammonia decomposition reactor, the inner diameter of the reactor is 25 cm, and the reactor comprises liquid metal, a porous metal tube, and a reaction chamber.

[0004] In practical applications, after heating the reactor, ammonia is introduced through the porous metal tube, and the ammonia is distributed and introduced through the porous metal tube. Under the catalytic action of liquid metal, the ammonia is decomposed into hydrogen and nitrogen. Industrial ammonia decomposition requires high temperature. This reactor uses liquid metal as a catalyst and distributes ammonia through a porous metal tube, which increases the contact area between the reaction gas and the liquid metal, improves the reaction efficiency, and reduces the reaction temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 It is a liquid metal ammonia decomposition reactor; in the figure: 1 liquid metal, 2 metal tube, 3 porous metal, 4 reactor shell, 5 ammonia inlet, 6 reaction product outlet. DETAILED DESCRIPTION

[0006] An ammonia decomposition reactor using liquid metal as a catalyst adopted in an embodiment of the present invention comprises a reaction container and a porous metal tube; the porous metal tube is a metal tube with one end sealed and the other end open, and a plurality of through holes are formed on the side wall surface of the metal tube to form the porous metal tube;

[0007] The reaction vessel is filled with liquid metal, and the porous metal tube is placed in the liquid metal in the reaction vessel. The open end of the porous metal tube is connected to the external ammonia gas source through another metal conduit. The inner diameter of the reaction vessel is 25 cm; the porous metal tube is placed vertically in the liquid metal with the open end at the top, and through holes are evenly distributed on the side wall surface.

[0008] Embodiment 1:

[0009] like Figure 1As shown, gallium copper liquid metal with a copper content of 0.05% wt is used and loaded into a reaction vessel with a filling depth of 10 cm. The aperture of the through hole opened on the side wall of the metal porous tube is 1 micron to 20 microns, the length is 9 cm, the porosity is 50%, the inner diameter of the stainless steel porous metal tube is 6 mm, and after welding with one end of a stainless steel metal conduit with an inner diameter of 6 mm, the metal porous tube is vertically placed in the liquid metal, and the metal porous tube is completely immersed in the liquid metal, and its uppermost open end is 1 cm away from the liquid surface (buried depth). Ammonia is introduced into the metal conduit from the other open end of the metal conduit, with a flow rate of 10 ml / min, and the ammonia pressure in the porous metal tube is 4 Bar. At room temperature and pressure, the product gas generation is detected at the upper open end (outlet) of the reaction vessel. The hydrogen flow rate is detected to be 12 ml / min, and the ammonia conversion rate is 80%.

[0010] Embodiment 2:

[0011] like Figure 1 As shown, gallium copper liquid metal with a copper content of 0.05% wt is used and loaded into a reaction vessel with a filling depth of 50 cm. The aperture of the through hole opened on the side wall of the metal porous tube is 1 micron to 30 microns, the length is 40 cm, the porosity is 55%, the inner diameter of the stainless steel porous metal tube is 6 mm, and after welding with one end of a stainless steel metal conduit with an inner diameter of 6 mm, the metal porous tube is vertically placed in the liquid metal, and the metal porous tube is completely immersed in the liquid metal, and its uppermost open end is 5 cm away from the liquid surface (buried depth). Ammonia is introduced into the metal conduit from the other open end of the metal conduit, with a flow rate of 300 ml / min, and the ammonia pressure in the porous metal tube is 4 Bar. At room temperature and pressure, the product gas generation is detected at the upper open end (outlet) of the reaction vessel. The hydrogen flow rate is detected to be 320 ml / min, and the ammonia conversion rate is 71%.

[0012] Embodiment 3:

[0013] like Figure 1 As shown, gallium copper liquid metal with a copper content of 0.05% wt is used and loaded into a reaction vessel with a filling depth of 70 cm. The aperture of the through hole opened on the side wall of the metal porous tube is 1 micron to 100 microns, the length is 80 cm, the porosity is 65%, the inner diameter of the stainless steel porous metal tube is 6 mm, and after welding with one end of a stainless steel metal conduit with an inner diameter of 6 mm, the metal porous tube is vertically placed in the liquid metal, and the metal porous tube is completely immersed in the liquid metal, and its uppermost open end is 10 cm away from the liquid surface (buried depth). Ammonia is introduced into the metal conduit from the other open end of the metal conduit, with a flow rate of 500 ml / min, and the ammonia pressure in the porous metal tube is 4 Bar. At room temperature and pressure, the product gas generation is detected at the upper open end (outlet) of the reaction vessel. The hydrogen flow rate is detected to be 470 ml / min, and the ammonia conversion rate is 63%.

Claims

1. An ammonia decomposition reactor using liquid metal as a catalyst, characterized in that: It includes a reaction container and a porous metal tube; the porous metal tube is a metal tube with one end sealed and the other end open, and a plurality of through holes are opened on the side wall of the metal tube to form the porous metal tube; The reaction container is filled with liquid metal, the porous metal tube is placed in the liquid metal in the reaction container, and the open end of the porous metal tube is connected with an external ammonia gas source through another metal conduit.

2. The reactor according to claim 1, characterized in that: The material of the liquid metal is: metallic gallium and one or more of copper, magnesium, vanadium and gold. The mass content of gallium in the liquid metal is 98% to 99.9%, and the total mass content of copper, magnesium, vanadium and gold is 2% to 0.1%. The filling height in the reactor is 0.1m to 1m.

3. The reactor according to claim 1, characterized in that: The porous metal tube is a porous stainless steel hollow tube, the open end of which is welded to one end of a two-end open stainless steel tube with the same inner diameter. The aperture of the through hole on the side wall of the porous metal tube is 1 micron to 100 microns (preferably 1 micron to 50 microns, more preferably 1 micron to 20 microns), the inner diameter of the porous metal tube is 5-7mm, the sum of the open end areas of the through holes on the outer surface of the side wall of the porous metal tube is 40% to 70% of the surface area of ​​the side wall of the porous metal tube (i.e., the porosity, preferably 45% to 55%), and the porous metal tube is completely immersed in liquid metal.

4. The reactor according to claim 1, characterized in that: The porous metal tube is placed vertically in the liquid metal with the opening end at the top, and the diameters of the through holes thereon are distributed from small to large from top to bottom; the through holes thereon are evenly distributed on the side wall surface; The distance between the upper opening end of the porous metal tube and the liquid metal surface is 0.5-30 cm, preferably 1-20 cm.

5. A method for carrying out ammonia decomposition reaction using the reactor according to any one of claims 1 to 4, characterized in that: It uses liquid metal as a catalyst and a porous metal tube as an air inlet distributor. Ammonia gas is introduced into the liquid metal through a metal conduit and the porous metal tube to perform an ammonia decomposition reaction.

6. The method according to claim 5, characterized in that: The reaction temperature of the liquid metal ammonia decomposition reactor membrane reactor is 20°C to 400°C (preferably 20-30°C), and the ammonia pressure in the porous metal tube is 1 Bar to 10 Bar (preferably 4 Bar).

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