Natural gas and water vapor mixing tank

Abstract

The utility model discloses a natural gas and water vapor mixing tank. An inner cavity of the tank body is divided into a steam cavity, a natural gas cavity and a mixed gas cavity from bottom to top through upper and lower partition plates. Laval nozzles are evenly distributed in the natural gas cavity, the Laval nozzles are communicated with the steam cavity and the natural gas cavity, and a plurality of evenly-distributed upward inclined holes are machined in thin necks and outlets of the Laval nozzles. A steam inlet is formed in the bottom of the steam cavity, and an arc plate is installed in the steam cavity and right faces the steam inlet. The upper portion of the mixed gas cavity is spherical, a mixed gas outlet is formed in the spherical top, a ball plate is arranged in the mixed gas cavity, and gas turbulent flow uniform mixing is achieved by means of space changes of the mixed gas cavity. The Laval nozzle is used for dispersing water vapor, natural gas is mixed into the inclined holes in the nozzle, and gas in the mixed gas cavity is in turbulent flow, so that uniform mixing is realized.

Description

Technical Field

[0001] The utility model is applied to the field of chemical industry and relates to a raw material mixed gas for manufacturing synthesis gas from natural gas, in particular to a mixing tank for turbulent mixing of natural gas and water vapor. Background Art

[0002] The catalytic reaction of natural gas and water vapor produces synthesis gas, which is a mixture of hydrogen and carbon monoxide. This synthesis gas can be used as a raw gas for the manufacture of a variety of chemicals, such as methanol or ammonia. The kinetics of the synthesis gas conversion reaction is determined by the diffusion rate of the gas. In order to ensure that the reaction of the synthesis gas conversion is thorough and smooth and to obtain synthesis gas with a low methane content, it is very necessary to uniformly mix the natural gas and water vapor in the raw gas, especially for large-scale synthesis gas production equipment, which can save equipment floor space and conversion energy.

[0003] In many patent applications for natural gas conversion to synthesis gas, there is a lack of description of uniform gas mixing. The main reason is that the production scale is small, the gas molecules diffuse quickly, and the impact of uniform gas mixing on production is ignored. For example, CN105347302B discloses a method for producing synthesis gas by natural gas conversion, CN100427384C discloses a method for preparing CO, synthesis gas and methanol by steam reforming hydrocarbons, and CN109694038A discloses a process system and conversion method for preparing synthesis gas by electrically heating light hydrocarbon reforming. All of them use pipelines, preheaters, or reactors for mixing, and no special gas mixing device is set. Utility Model Content

[0004] The technical problem solved by the utility model is to provide a natural gas and water vapor mixing tank, which utilizes the relevant principles of gas flow to increase the turbulence degree of the gas and realize uniform mixing of the natural gas and water vapor, and is specially configured for large-scale synthetic gas production equipment.

[0005] The technical solution adopted by the utility model is that the inner cavity of the natural gas and water vapor mixing tank is divided into a steam cavity, a natural gas cavity and a mixed gas cavity from bottom to top by an upper partition and a lower partition. A plurality of evenly distributed Laval nozzles are arranged in the natural gas cavity; the Laval nozzle connects the steam cavity and the natural gas cavity, and a plurality of evenly distributed upward inclined holes are processed on the narrow neck and the outlet of the Laval nozzle.

[0006] Furthermore, a steam inlet is arranged at the bottom of the steam chamber, and an arc plate is installed in the steam chamber, the arc plate is directly opposite to the steam inlet and fixed on the lower partition plate. Alternatively, the steam inlet is replaced by a double gas inlet, and the double gas inlet is a steam inlet inside an exhaust gas inlet.

[0007] Furthermore, the upper part of the mixed gas chamber is spherical, and a mixed gas outlet is arranged on the top of the sphere. A ball plate is arranged in the mixed gas chamber, and the ball plate is fixed on the upper partition plate, and its center is concentric with the spherical shape of the upper part of the mixed gas chamber. The ball plate is a whole sphere or a hemisphere. By utilizing the change of the mixed gas chamber space, the gas turbulence is uniformly mixed.

[0008] Furthermore, the natural gas chamber is connected to a natural gas inlet, and the natural gas inlet is tangent to or perpendicular to the circular tank body.

[0009] Furthermore, the outer surface of the tank body is wrapped with an outer insulation layer, and the inner surface is pasted with an inner insulation layer to ensure the temperature of the gas without dissipating heat.

[0010] The beneficial effects of the utility model are as follows: the utility model uses uniformly distributed Laval nozzles to disperse water vapor, Laval airflow negative pressure, and the uniformly distributed oblique holes on the nozzles mix natural gas, thereby increasing the contact area between water vapor and natural gas. The ball plate arranged in the mixed gas cavity changes the airflow space size, generates turbulence, and achieves the purpose of uniform mixing. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram of the main structure of Example 1;

[0012] Figure 2 yes Figure 1 AA cross-sectional view of ;

[0013] Figure 3 yes Figure 1 A partial enlarged view of the inclined hole;

[0014] Figure 4 is a schematic diagram of the main structure of Example 2;

[0015] Figure 5 is a top view schematic diagram of Example 3;

[0016] In the figure: 1-mixed gas outlet, 2-natural gas inlet, 3-steam inlet, 4-steam chamber, 5-lower baffle, 6-Laval nozzle, 7-inclined hole, 8-upper baffle, 9-natural gas chamber, 10-mixed gas chamber, 11-ball plate, 12-tank body, 13-outer insulation layer, 14-inner insulation layer, 15-arc plate, 16-exhaust gas inlet. DETAILED DESCRIPTION

[0017] The following is attached Figure 1 The gas flows from bottom to top based on the top and bottom of the pipe. Example

[0018] The structure of the natural gas and water vapor mixing tank in this embodiment is as shown in the attached figure. Figure 1 and attached Figure 2The inner cavity of the tank body is divided into a steam chamber 4, a natural gas chamber 9 and a mixed gas chamber 10 from bottom to top by a lower partition 5 and an upper partition 8. A plurality of evenly distributed Laval nozzles 6 are arranged in the natural gas chamber 9, and the Laval nozzles 6 are connected to the steam chamber 4 and the natural gas chamber 9. A plurality of evenly distributed upward inclined holes 7 are processed on the narrow neck and the outlet of the Laval nozzle 6, as shown in the attached figure. Figure 3 As shown, the inclined hole 7 allows the natural gas flow to flow toward the mixed gas chamber 10 .

[0019] A steam inlet 3 is arranged at the bottom of the steam chamber 4, and an arc plate 15 is installed in the steam chamber 4. The arc plate 15 is fixed on the bottom surface of the lower partition plate 5 and is directly opposite to the steam inlet 3. The natural gas chamber 9 is connected to the natural gas inlet 2, and the natural gas inlet 2 is tangent to the circular tank body 12, guiding the natural gas to enter the natural gas chamber 9 tangentially. The upper part of the mixed gas chamber 10 is spherical, and the mixed gas outlet 1 is arranged on the top of the sphere. A ball plate 11 is arranged in the mixed gas chamber 10, and the center of the ball plate 11 is concentric with the spherical upper part of the mixed gas chamber, so as to ensure that the ball plate 11 is consistent in size with the inner wall of the tank body.

[0020] When the mixing tank is working, in order to prevent the gas temperature from dropping, an outer insulation layer 13 is wrapped around the outer surface of the tank body 12. Although the tank body material can meet the high temperature of the mixed gas, in order to prevent the thermal stress damage caused by the thermal expansion and contraction of the tank body, an inner insulation layer 14 is attached to the inner surface of the tank body 12. The inner insulation layer 14 needs to meet the impact of the airflow and be firmly bonded to the tank body 12.

[0021] When this embodiment is used, water vapor flows into the steam chamber 4 from the steam inlet 3 at high speed. When the water vapor hits the arc plate 15, the kinetic energy of the water vapor is converted into potential energy, generating turbulence and high pressure in the steam chamber 4. High-pressure water vapor flows from the Laval nozzle 6 to the mixed gas chamber 10 at high speed. A slight negative pressure is generated on the side of the high-speed airflow at the narrow neck and outlet of the Laval nozzle 6, that is, a slight negative pressure is generated at the outlet of the inclined hole 7. The natural gas from the natural gas inlet 2 enters the natural gas chamber 9 at high speed and tangentially, generating turbulence. Similarly, the kinetic energy is converted into potential energy, which is conducive to the uniform pressure of the inclined hole 7 on each Laval nozzle 6. There is a positive and negative pressure difference at the inlet and outlet of the inclined hole 7, so that the natural gas enters the nozzle from the inclined hole 7 and flows into the mixed gas chamber 10 quickly together with the water vapor. The water vapor and natural gas entering the mixed gas chamber 10 from the Laval nozzle 6 have a gas flow rate that is reduced due to the sudden increase in space, and the water vapor and natural gas are turbulently mixed, and the kinetic energy of the gas is converted into potential energy. The ball plate 11 arranged in the mixed gas chamber 10 reduces the space for gas flow, and the flowing gas is turbulently mixed again, and the potential energy of the gas is converted into kinetic energy. The water vapor and natural gas after being evenly mixed become mixed gas, and flow out of the mixing tank from the mixed gas outlet 1. The purpose of using a spherical shape on the upper part and inside of the mixed gas chamber 10 is to utilize the Coanda wall effect to reduce the resistance of gas flow, and only by changing the spatial size, the conversion of gas kinetic energy and potential energy is achieved, and the turbulent and even mixing of water vapor and natural gas is realized.

[0022] This embodiment uses multiple Laval nozzles to disperse water vapor, uses the negative pressure of Laval airflow to mix natural gas, and uses multiple inclined holes on the Laval nozzle to increase the contact area between water vapor and natural gas, laying the foundation for uniform mixing of water vapor and natural gas in a small space. A ball plate is set in the mixed gas chamber, and the change in space size is used to make water vapor and natural gas produce turbulence, thereby greatly achieving the purpose of uniform mixing without increasing the resistance of gas flow. Example

[0023] Attached Figure 4 This is a schematic diagram of the structure of the natural gas and water vapor mixing tank in this embodiment. Compared with Example 1, the following changes are made:

[0024] 1) The ball plate 11 is changed from a whole sphere to a hemisphere. The mixed gas chamber 10 is changed from the change of the gas flow space from large to small in Example 1 to the change of the flow space from large to small and then from small to large, so that the gas turbulence is increased and the mixing uniformity is better.

[0025] 2) The steam inlet 3 in Example 1 is changed to a double gas inlet, that is, the tail gas inlet 16 is enclosed in the steam inlet 3. The tail gas comes from the reformer and is the tail gas after the combustion of natural gas, containing carbon dioxide, water vapor and a small amount of oxygen. When the water vapor flows into the steam chamber 4 at a high speed from the steam inlet 3, the tail gas is mixed with the water vapor at the tail gas inlet 16 by using the principle of the venturi tube, and enters the steam chamber 4 together. The tail gas and the water vapor are turbulently mixed in the steam chamber, and then mixed with the natural gas in the Laval nozzle. In the mixed gas chamber, all the gases are turbulently mixed and uniform.

[0026] Compared with Example 1, the tail gas entering the mixing tank in this embodiment utilizes the heat after combustion in the converter and increases the content of carbon dioxide in the mixed gas. The hydrogen-carbon ratio in the synthesis gas can be adjusted by carbon dioxide, making the production control of the synthesis gas more flexible. Example

[0027] This embodiment is shown in the attached Figure 5 As shown, the difference from the above embodiment is that the natural gas inlet 2 is not tangential to the circular tank body, but perpendicular, and the natural gas directly enters the center of the natural gas chamber 9 from the spacing space of the Laval nozzle 6, and then turbulently, the kinetic energy is converted into potential energy, and the pressure increases. In order to make the pressure in the natural gas chamber 9 uniform, when the natural gas enters the natural gas chamber, it is not suitable to be blocked by the Laval nozzle 6. Therefore, the position of the natural gas inlet 2 of this embodiment is related to the design position of the Laval nozzle 6.

[0028] In the process of gas flow, the utility model adopts the transformation of kinetic potential energy and spatial change to achieve turbulent mixing of gas, so as to achieve the purpose of uniform gas mixing. In terms of structural design, the utility model mostly adopts arc shape, spherical shape, etc., and uses the Coanda wall effect to minimize the resistance of gas flow. Only the arc plate is set at the steam inlet to block the water vapor, the purpose of which is to equalize the pressure in the steam chamber, avoid the water vapor short circuit, and cause uneven flow of the Laval nozzle.

Claims

1. A natural gas and water vapor mixing tank, characterized in that: The inner cavity of the tank body is divided into a steam cavity (4), a natural gas cavity (9) and a mixed gas cavity (10) from bottom to top by a lower baffle (5) and an upper baffle (8); uniformly distributed Laval nozzles (6) are arranged in the natural gas cavity (9); the Laval nozzle (6) connects the steam cavity (4) and the natural gas cavity (9), and uniformly distributed upward inclined holes (7) are processed on the narrow neck and the outlet of the Laval nozzle (6).

2. A natural gas and water vapor mixing tank according to claim 1, characterized in that: A steam inlet (3) is provided at the bottom of the steam chamber (4), and an arc plate (15) is installed in the steam chamber (4). The arc plate (15) is directly opposite to the steam inlet (3) and is fixed on the lower partition plate (5).

3. A natural gas and water vapor mixing tank according to claim 2, characterized in that: The steam inlet (3) is replaced by a dual gas inlet, wherein the dual gas inlet is an exhaust gas inlet (16) and an inner shell of the steam inlet (3).

4. A natural gas and water vapor mixing tank according to claim 1, characterized in that: The upper part of the mixed gas chamber (10) is spherical, and a mixed gas outlet (1) is arranged on the top of the sphere; a spherical plate (11) is arranged in the mixed gas chamber (10), and the center of the spherical plate (11) is concentric with the upper spherical part of the mixed gas chamber.

5. A natural gas and water vapor mixing tank according to claim 4, characterized in that: The ball plate (11) is a full sphere or a hemisphere.

6. A natural gas and water vapor mixing tank according to claim 1, characterized in that: The natural gas chamber (9) is connected to the natural gas inlet (2), and the natural gas inlet (2) is tangential to or perpendicular to the circular tank body.

7. The natural gas and water vapor mixing tank according to claim 1, characterized in that: The outer surface of the tank is wrapped with an outer insulation layer (13), and the inner surface is adhered with an inner insulation layer (14).

Images