Chemical loop system and process

Abstract

A chemical loop system and process capable of adjusting the ratio of hydrogen production to heat generation. In an embodiment, the system comprises a cyclone separator, a burner, a reducer, an oxidizer, a buffer tank and an air supply device, which can be sequentially connected from top to bottom. In addition, the system further comprises a riser pipe, by means of which the air supply device at the bottom is in communication with the cyclone separator at the top end, wherein carrier particles can be continuously circulated vertically in the system.

Description

Chemical circuit system and procedure Technical Field

[0001] This invention relates to a chemical circuit system and procedure, and more particularly to a chemical circuit system and procedure for hydrogen production. Background Technology

[0002] In general fluidized bed reaction systems, the carrier particles are mainly powders with a particle size of less than 1 mm, which facilitates fluidized reaction in dual-reactor (air reactor / burner, reducer) systems. The system is relatively simple, but the reduction degree of the carrier particles is also low, making it less suitable for hydrogen production. Summary of the Invention

[0003] One embodiment of the present invention provides a chemical loop system with an adjustable ratio of hydrogen production to heat production, comprising:

[0004] A cyclone separator can separate multiple carrier particles from an airflow and convey those carrier particles downwards;

[0005] A burner is used to generate heat and receive carrier particles from the cyclone separator, wherein the carrier particles absorb the heat and can leave the burner and be conveyed downwards;

[0006] A reducer is used to receive and reduce the carrier particles leaving the burner, wherein the carrier particles can react with hydrocarbon fuel and after reduction can form multiple hydrogen-producing path particles and multiple non-hydrogen-producing path particles, which leave the reducer and are conveyed downwards respectively.

[0007] An oxidizer is used to receive and oxidize the hydrogen-producing pathway particles from the reducer, wherein the hydrogen-producing pathway particles can react with water vapor and leave the oxidizer after oxidation and be conveyed downwards.

[0008] A buffer tank is used to receive and mix the non-hydrogen-producing path particles from the reducer and the hydrogen-producing path particles from the oxidizer, thereby forming multiple particles to be heated.

[0009] A first non-mechanical valve, including a first gas inlet, is used to regulate a first mass flow rate through the first non-mechanical valve, wherein the first non-mechanical valve is connected to the reducer and the oxidizer and can be used to transport the hydrogen-producing path particles.

[0010] A second non-mechanical valve, including a second gas inlet, is used to regulate a second mass flow rate through the second non-mechanical valve, wherein the second non-mechanical valve is connected to the reducer and the buffer tank and can be used to transport particles that are not produced by hydrogen production pathways.

[0011] Another embodiment of the present invention provides a chemical circuit method for adjusting the ratio of hydrogen production to heat production, comprising:

[0012] Multiple carrier particles undergo a reduction reaction in a reducer, and then multiple hydrogen-producing path particles among the carrier particles are conveyed downwards at a first mass flow rate via a first non-mechanical valve, and multiple non-hydrogen-producing path particles among the carrier particles are conveyed downwards at a second mass flow rate via a second non-mechanical valve, wherein the first mass flow rate and the second mass flow rate are adjustable.

[0013] These hydrogen-producing pathway particles enter the oxidizer, react with water vapor to produce hydrogen, and then are conveyed downwards out of the oxidizer;

[0014] The hydrogen-producing particles leaving the oxidizer and the non-hydrogen-producing particles leaving the reducer enter a buffer tank respectively, then mix to form multiple particles to be heated, and then convey them downwards from the buffer tank via an exit line.

[0015] The particles to be heated leaving the buffer tank are supplied with a first air flow rate by an air supply device and are conveyed upward to a burner via an ascending pipe, wherein the ascending pipe includes a blower to provide a second air flow rate. Attached Figure Description

[0016] Figure 1 is a schematic diagram of a chemical loop system suitable for hydrogen production according to one embodiment of the present invention. Detailed Implementation

[0017] Referring to Figure 1, a chemical loop system, in one embodiment, includes a cyclone separator 1, a burner 2, a reducer 3, an oxidizer 4, a buffer tank 5, and a gas supply device 6, which can be sequentially connected from top to bottom; an ascender pipe 7 connects the gas supply device 6 at the bottom and the cyclone separator 1 at the top; carrier particles can continuously circulate up and down in this system. In one embodiment, the reducer 4 is connected to the oxidizer 4 via a first L valve 8, and to the buffer tank 5 via a second L valve 9. In one embodiment, both the reducer 3 and the oxidizer 4 are counter-current moving bed designs. In one embodiment, the L valve can be replaced by other non-mechanical valves, such as J valves. In one embodiment, the particle size of the carrier particles is approximately 1 millimeter (mm). In one embodiment, the gas supply device 6 includes a Venturi valve and a gas supply line, wherein one end of the gas supply line is a Venturi valve, and the other end is connected to the ascender pipe 7; furthermore, the buffer tank 5 is connected downwards to this gas supply line. In one embodiment, the riser 7 includes a blower at the bottom and is connected to the cyclone separator 1 at the top.

[0018] In one embodiment, the carrier particles comprise metal oxides and a ceramic matrix, which can be used for carrying oxygen and heat. In one embodiment, the iron-based carrier particles undergo an exothermic oxidation reaction with air in the burner 2. The carrier particles can be heated to 1000 degrees Celsius and produce fully oxidized iron oxide (Fe2O3), and the heat released by the oxidation reaction can be used for additional power generation. In one embodiment, the heat carried by the carrier particles through heating and the oxygen carried by complete oxidation are sufficient to supply the needs of the carrier particles and fuel reaction in the reducer 3. In one embodiment, the carrier particles, carrying oxygen and heat, leave the burner 2 and are transferred downwards to the reducer 3, where they react with the fuel, releasing oxygen and being reduced to metallic iron or lower-order oxidized FeO. In one embodiment, the fuel may be a hydrocarbon fuel, such as natural gas (methane), syngas, pulverized coal, biomethane, or fragmented biochar, which is input from the bottom of the reducer 3 and reacts with carrier particles falling from above. The reaction products may be carbon dioxide and water vapor, which are output from the reducer 3. In another embodiment, the carrier particles are particles with a diameter greater than 1 mm, which can increase the porosity between the carrier particles packed in the reducer 3, thereby increasing the chance of the carrier particles reacting with the fuel and resulting in a higher degree of reduction of the carrier particles.

[0019] In one embodiment, after the carrier particles react with the fuel, including being reduced to metallic iron (Fe) and lower-order oxidized FeO, they can leave the reducer 3 via hydrogen-producing and non-hydrogen-producing paths, respectively. In one embodiment, in the hydrogen-producing path, a first L-valve 8 transmits a portion of the carrier particles to the oxidizer 4 via steam, while in the non-hydrogen-producing path, a second L-valve 9 transmits the remaining portion of the carrier particles to the buffer tank 5 via nitrogen. In one embodiment, the first L-valve 8 includes a first gas injection port for injecting steam, and the second L-valve 9 includes a second gas injection port for injecting nitrogen. The isolation of the gases and the disturbance of the airflow help prevent the carrier particles from agglomerating and sintering at high temperatures. In one embodiment, adjusting the gas injection flow rates of the first and second gas injection ports controls the mass flow rate of the carrier particles delivered to the oxidizer 4 and the buffer tank 5, thereby adjusting the ratio of hydrogen production to heat production in the system. In one embodiment, the hydrogen-producing path includes the first L-valve 8 and the oxidizer 4.

[0020] In one embodiment, water vapor is input from the bottom of the oxidizer 4 and reacts with carrier particles falling from above. The reaction products may be hydrogen and water vapor, which are output from the oxidizer 4. The carrier particles may be partially oxidized to ferrous oxide (Fe3O4) and then leave the oxidizer 4, being conveyed downwards to the buffer tank 5. In another embodiment, the buffer tank 5 provides sufficient space to collect and mix carrier particles from the reducer 3 and the oxidizer 4 at different carrier flow rates and oxidation states. These particles are then conveyed together through a discharge line from the buffer tank 5 to the gas supply line of the gas supply device 6.

[0021] In a comparative embodiment, the carrier particles from the reducer 3 and the oxidizer 4 are collected, mixed and transported directly through a single pipeline without passing through the buffer tank 5, which can easily lead to blockage.

[0022] In one embodiment, to allow the carrier particles to circulate back to combustion chamber 2 for further oxidation and heating, the gas supply device 6 provides a gas flow rate using nitrogen as a medium via a Venturi valve, conveying the carrier particles received in the gas supply line to the riser pipe 7. In another embodiment, the riser pipe 7 is supplied with gas, such as nitrogen or air, at high speed by a blower at a different gas flow rate, which, together with the gas supply device 6, provides the power for the carrier particles to be heated to rise. In another embodiment, an airflow is formed in the riser pipe 7, which can convey the carrier particles from the bottom end to the top end of the riser pipe 7 within two to three seconds. Then, the carrier particles are separated from the airflow by the cyclone separator 1, and then the carrier particles are conveyed downward to the burner 2. In another embodiment, the moving bed structure burner 2 is placed above the reducer 3, allowing the carrier particles to be completely oxidized and release heat in the burner 3. Without undergoing other transfer procedures, additional heat loss is avoided, and the particles directly carry sufficient heat from the reduction reaction and fall to the reducer 3 by gravity for the next oxidation-reduction reaction to produce hydrogen and heat.

[0023] Legend: 1. Cyclone separator; 2. Burner; 3. Reducer; 4. Oxidizer; 5. Buffer tank; 6. Gas supply device; 7. Ascend pipe; 8. First L valve; 9. Second L valve.

Claims

1. A chemical circuit system, comprising: A cyclone separator can separate multiple carrier particles from an airflow and convey those carrier particles downwards; A burner is used to generate heat and receive carrier particles from the cyclone separator, wherein the carrier particles absorb the heat and can leave the burner and be conveyed downwards; A reducer is used to receive and reduce the carrier particles leaving the burner, wherein the carrier particles can react with hydrocarbon fuel and after reduction can form multiple hydrogen-producing path particles and multiple non-hydrogen-producing path particles, which leave the reducer and are conveyed downwards respectively. An oxidizer is used to receive and oxidize the hydrogen-producing pathway particles from the reducer, wherein the hydrogen-producing pathway particles can react with water vapor and leave the oxidizer after oxidation and be conveyed downwards. A buffer tank is used to receive and mix the non-hydrogen-producing path particles from the reducer and the hydrogen-producing path particles from the oxidizer, thereby forming multiple particles to be heated. A first non-mechanical valve, including a first gas inlet, is used to regulate a first mass flow rate through the first non-mechanical valve, wherein the first non-mechanical valve is connected to the reducer and the oxidizer and can be used to transport the hydrogen-producing path particles. A second non-mechanical valve, including a second gas inlet, is used to regulate a second mass flow rate through the second non-mechanical valve, wherein the second non-mechanical valve is connected to the reducer and the buffer tank and can be used to transport particles that are not produced by hydrogen production pathways.

2. The system as described in claim 1, wherein, The first non-mechanical valve includes a first L valve, and the second non-mechanical valve includes a second L valve.

3. The system as described in claim 1, wherein, This hydrocarbon fuel includes natural gas.

4. The system as described in claim 1, wherein, The first gas injection port can inject water vapor, and the second gas injection port can inject nitrogen.

5. The system as described in claim 1, wherein, These carrier particles include multiple iron-based oxygen carrier particles.

6. The system as described in claim 1, wherein, These carrier particles are millimeter in size.

7. The system as described in claim 1, further comprising: An air supply device includes a Venturi valve and an air supply line, wherein the air supply line can receive the particles to be heated conveyed downward, and then the Venturi valve provides a first air supply flow rate to convey the particles to be heated along the air supply line. An ascender pipe includes a blower, wherein the ascender pipe can receive the particles to be heated conveyed along the air supply line, and then the blower provides a second air supply flow to convey the particles to be heated upward along the ascender pipe to the cyclone separator.

8. A chemical circuit procedure, comprising: Multiple carrier particles undergo a reduction reaction in a reducer, and then multiple hydrogen-producing path particles among the carrier particles are conveyed downwards at a first mass flow rate via a first non-mechanical valve, and multiple non-hydrogen-producing path particles among the carrier particles are conveyed downwards at a second mass flow rate via a second non-mechanical valve, wherein the first mass flow rate and the second mass flow rate are adjustable. These hydrogen-producing pathway particles enter the oxidizer, react with water vapor to produce hydrogen, and then are conveyed downwards out of the oxidizer; The hydrogen-producing particles leaving the oxidizer and the non-hydrogen-producing particles leaving the reducer enter a buffer tank respectively, then mix to form multiple particles to be heated, and then convey them downwards from the buffer tank via an exit line. The particles to be heated leaving the buffer tank are supplied with a first air flow rate by an air supply device and are conveyed upward to a burner via an ascending pipe, wherein the ascending pipe includes a blower to provide a second air flow rate.

9. The procedure as described in claim 8, wherein, The first non-mechanical valve includes a first L valve, and the second non-mechanical valve includes a second L valve.

10. The procedure as described in claim 8, wherein, The first non-mechanical valve includes a first gas injection port for injecting water vapor to regulate the first mass flow rate, and the second non-mechanical valve includes a second gas injection port for injecting nitrogen to regulate the second mass flow rate.

11. The procedure as described in claim 8, wherein, These carrier particles include multiple iron-based oxygen carrier particles.

12. The procedure as described in claim 8, wherein, These carrier particles are millimeter in size.

13. The procedure as described in claim 8, wherein, The gas supply device includes a Venturi valve and a gas supply line connected to the riser pipe.

14. The procedure as described in claim 8, wherein, The burner is connected downwards to the reducer.

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