Chemical loop system

Abstract

A chemical loop system capable of adjusting the ratio of produced hydrogen to produced heat in one embodiment comprises a cyclone separator, a combustor, a reducer, an oxidizer, a buffer tank and a gas supply device which can be sequentially communicated from top to bottom, the ascending pipe is used for communicating the air supply device at the bottom and the cyclone separator at the top end; wherein the carrier particles can continuously circulate up and down in the system.

Description

TECHNICAL FIELD

[0001] The present application relates to a chemical loop system, in particular, to a chemical loop system for hydrogen production. BACKGROUND

[0002] In a general fluidized bed reaction system, the carrier particles are mainly powder with a particle size less than 1 mm, which is convenient for fluidized reaction in a two-reactor (air reactor / combustor, reducer) system. The system is relatively simple, and the reduction degree of the carrier particles is also relatively low, which is not suitable for hydrogen production. SUMMARY

[0003] One embodiment of the present application provides a chemical loop system capable of adjusting the ratio of hydrogen production and heat production, comprising:

[0004] A cyclone separator is configured to separate a plurality of carrier particles from a gas stream and to downwardly convey the carrier particles;

[0005] A combustor is configured to generate heat and to receive the carrier particles from the cyclone separator, wherein the carrier particles, after absorbing the heat, can exit the combustor and be downwardly conveyed;

[0006] A reducer is configured to receive and reduce the carrier particles exiting the combustor, wherein the carrier particles can react with a hydrocarbon fuel, and after reduction, form a plurality of hydrogen production path particles and a plurality of non-hydrogen production path particles, which are respectively downwardly conveyed from the reducer;

[0007] An oxidizer is configured to receive and oxidize the hydrogen production path particles from the reducer, wherein the hydrogen production path particles can react with water vapor, and after oxidation, exit the oxidizer and be downwardly conveyed;

[0008] A buffer tank is configured to receive and mix the non-hydrogen production path particles from the reducer and the hydrogen production path particles from the oxidizer, thereby forming a plurality of particles to be heated;

[0009] A first non-mechanical valve includes a first gas injection port and is configured to adjust a first mass flow rate passing through the first non-mechanical valve, wherein the first non-mechanical valve is connected to the reducer and the oxidizer and is configured to convey the hydrogen production path particles;

[0010] A second non-mechanical valve includes a second gas injection port and is configured to adjust a second mass flow rate passing through the second non-mechanical valve, wherein the second non-mechanical valve is connected to the reducer and the buffer tank and is configured to convey the non-hydrogen production path particles. BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. 1 is a schematic diagram of an embodiment of the present application, which is a chemical loop system suitable for hydrogen production. DETAILED DESCRIPTION

[0012] Reference Figure 1 A chemical loop system, in one embodiment, comprises a cyclone 1, a combustor 2, a reducer 3, an oxidizer 4, a buffer tank 5, and a gas feeding device 6, which are sequentially connected from top to bottom; an upcomer 7 connects the bottom gas feeding device 6 and the top cyclone 1; carrier particles can be circulated in the system. In one embodiment, the reducer 4 is connected to the oxidizer 4 by a first L-valve 8, and connected to the buffer tank 5 by a second L-valve 9. In one embodiment, both the reducer 3 and the oxidizer 4 are designed as countercurrent moving beds. In one embodiment, the L-valves can be replaced by other non-mechanical valves, such as J-valves. In one embodiment, the carrier particles have a particle size of about 1 millimeter (mm). In one embodiment, the gas feeding device 6 comprises a venturi valve and a gas feeding line, wherein one end of the gas feeding line is connected to the venturi valve, the other end is connected to the upcomer 7, and the buffer tank 5 is connected to the gas feeding line. In one embodiment, the upcomer 7 comprises a blower arranged at the bottom end, and the top end is connected to the cyclone 1.

[0013] In one embodiment, the carrier particles comprise metal oxides and ceramic supports, which can be used to carry oxygen and heat. In one embodiment, the iron-based carrier particles generate an exothermic oxidation reaction with air in the combustor 2, the carrier particles can be heated to 1000 degrees Celsius and generate fully oxidized iron (Fe2O3), and the heat energy released by the oxidation reaction can also be used for power generation. In one embodiment, the carrier particles carry the heat by heating and carry the oxygen by full oxidation, which is sufficient to supply the carrier particles and the fuel to react in the reducer 3. In one embodiment, the carrier particles carrying oxygen and heat leave the combustor 2 and are sent downward to the reducer 3 to react with the fuel therein, releasing oxygen and reducing to metallic iron or low-oxidation-state FeO. In one embodiment, the fuel can be a hydrocarbon fuel, such as natural gas (methane), synthetic gas, pulverized coal, bio-methane, or crushed biochar, which is input from the bottom of the reducer 3 and reacts with the carrier particles falling from above, wherein the reaction products can be carbon dioxide and water vapor, which are output from the reducer 3. In one embodiment, the carrier particles are in the form of particles with a particle size greater than 1 mm, which can increase the porosity between the carrier particles accumulated in the reducer 3, thereby increasing the opportunity for the carrier particles to react with the fuel and making the reduction degree of the carrier particles higher.

[0014] In one embodiment, after the carrier particles react with the fuel, including reduced iron Fe in metallic state and FeO in low oxidation state, can leave the reducer 3 via a hydrogen production path and a non-hydrogen production path. In one embodiment, in the hydrogen production path, the first L valve 8 transports a portion of the carrier particles to the oxidizer 4 by water vapor, and in the non-hydrogen production path, the second L valve 9 transports another portion of the carrier particles to the buffer tank 5 by nitrogen gas. In one embodiment, the first L valve 8 includes a first gas injection port for injecting water vapor, and the second L valve 9 includes a second gas injection port for injecting nitrogen gas, which can assist in avoiding high-temperature agglomeration and sintering of the carrier particles by isolating the carrier particles from the high-temperature environment and disturbing the flow of the carrier particles. In one embodiment, by adjusting the gas injection flow rates of the first and second gas injection ports, the mass flow rates of the carrier particles transported to the oxidizer 4 and the buffer tank 5 can be controlled, thereby adjusting the ratio of hydrogen production to heat production of the system. In one embodiment, the hydrogen production path includes the first L valve 8 and the oxidizer 4.

[0015] In one embodiment, water vapor is input from the bottom of the oxidizer 4 and reacts with the carrier particles falling from above, wherein the products of the reaction can be hydrogen gas and water vapor, which are output from the oxidizer 4, and the carrier particles can be partially oxidized to ferrous oxide (Fe3O4) and then leave the oxidizer 4 to be transported downward to the buffer tank 5. In one embodiment, the buffer tank 5 provides sufficient space to collect and mix carrier particles of different oxidation states from the reducer 3 and the oxidizer 4, and then the carrier particles are transported together to the gas delivery device 6 via a single pipeline.

[0016] In one comparative embodiment, the carrier particles from the reducer 3 and the oxidizer 4 are directly collected, mixed, and transported via a single pipeline without passing through the buffer tank 5, which can easily cause blockage.

[0017] In one embodiment, in order to be able to circulate back to the combustor 2 for further oxidation and heating, the gas delivery device 6 provides a gas delivery flow rate by using a Venturi valve with nitrogen gas as the medium to transport the carrier particles received by the gas delivery pipeline to the riser 7. In one embodiment, the riser 7 provides a high-speed gas flow, such as nitrogen gas or air, by using a blower at another gas delivery flow rate, which, in combination with the gas delivery device 6, provides the power for the carrier particles to be heated to rise. In one embodiment, the gas flow in the riser 7 can transport the carrier particles from the bottom end to the top end of the riser 7 within two to three seconds, and then the carrier particles are separated from the gas flow by the cyclone separator 1, and then the carrier particles are transported downward to the combustor 2. In one embodiment, the combustor 2 with a moving bed architecture is placed above the reducer 3, which allows the carrier particles to be completely oxidized and exothermic in the combustor 3, and then the carrier particles can avoid additional heat loss by not going through other transportation procedures and can directly carry enough heat from the reduction reaction to drop by gravity to the reducer 3 for the next redox reaction to produce hydrogen and heat.

[0018] 1 cyclone separator;

[0019] 2 burner;

[0020] 3 reducer;

[0021] 4 oxidizer;

[0022] 5 buffer tank;

[0023] 6 gas feeding device;

[0024] 7 riser;

[0025] 8 first L valve;

[0026] 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 chemical circuit system according to claim 1, characterized in that, The first non-mechanical valve includes a first L valve, and the second non-mechanical valve includes a second L valve.

3. The chemical circuit system according to claim 1, characterized in that, This hydrocarbon fuel includes natural gas.

4. The chemical loop system according to claim 1, characterized in that, The first gas injection port can inject water vapor, and the second gas injection port can inject nitrogen.

5. The chemical loop system according to claim 1, characterized in that, These carrier particles include multiple iron-based oxygen carrier particles.

6. The chemical loop system according to claim 1, characterized in that, These carrier particles are millimeter in size.

7. The chemical loop system according to claim 1, characterized in that: 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.

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