Nested-Flow Heat Exchangers and Chemical Reactors

• US 20160282052A1
• Filed: 03/12/2015
• Published: 09/29/2016
• Est. Priority Date: 03/12/2015
• Status: Active Grant

• Current Assignee: BayoTech, Inc.
• Original Assignee: BayoTech, Inc.
• Inventors: Vernon, Milton Edward
• Granted Patent: US 9,958,211 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01J 12/007 in the presence of catalytically active bodies, e.g. porous plates
• CPC Class Codes: B01J 2208/00212 Plates; Jackets; Cylinders
• CPC Class Codes: B01J 2208/00309 with two or more reactions in heat exchange with each other, such as an endothermic reaction in heat exchange with an exothermic reaction
• CPC Class Codes: B01J 2208/0053 Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
• CPC Class Codes: B01J 2208/025 Two or more types of catalyst
• CPC Class Codes: B01J 2219/00495 Means for heating or cooling the reaction vessels
• CPC Class Codes: B01J 2219/0072 Organic compounds
• CPC Class Codes: B01J 2219/00745 Inorganic compounds
• CPC Class Codes: B01J 8/008 Details of the reactor or of the particulate material; Processes to increase or to retard the rate of reaction B01J8/0285, B01J8/067, B01J8/087, B01J8/1836 take precedence
• CPC Class Codes: B01J 8/0257 in a cylindrical annular shaped bed
• CPC Class Codes: B01J 8/0278 Feeding reactive fluids for solid material B01J8/0015
• CPC Class Codes: B01J 8/0285 Heating or cooling the reactor for tubular reactors in furnaces B01J8/062
• CPC Class Codes: B01J 8/0465 the beds being concentric
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0283 containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 2203/068 Ammonia synthesis
• CPC Class Codes: C01B 2203/0811 by combustion of fuel
• CPC Class Codes: C01B 2203/1241 Natural gas or methane
• CPC Class Codes: C01B 2203/82 Several process steps of C01B2203/02 - C01B2203/08 integrated into a single apparatus
• CPC Class Codes: C01B 3/384 the catalyst being continuously externally heated
• CPC Class Codes: C01B 3/48 : followed by reaction of water vapour with carbon monoxide
• CPC Class Codes: C01C 1/0417 : characterised by the synthesis reactor, e.g. arrangement of catalyst beds and heat exchangers in the reactor arrangement of several reactors C01C1/0405; fixed-bed reactors in general B01J8/02
• CPC Class Codes: C01C 1/0482 : Process control; Start-up or cooling-down procedures
• CPC Class Codes: C05C 9/00 : Fertilisers containing urea or urea compounds
• CPC Class Codes: C07C 273/04 : from carbon dioxide and ammonia
• CPC Class Codes: F28D 2021/0022 : for chemical reactors
• CPC Class Codes: F28D 7/103 : consisting of more than two coaxial conduits or modules of more than two coaxial conduits
• CPC Class Codes: F28D 7/12 : the surrounding tube being closed at one end, e.g. return type F28D7/14 takes precedence
• CPC Class Codes: F28F 1/122 : and being formed of wires
• CPC Class Codes: H01M 2250/10 : Fuel cells in stationary systems, e.g. emergency power source in plant
• CPC Class Codes: H01M 8/0618 : Reforming processes, e.g. autothermal, partial oxidation or steam reforming
• CPC Class Codes: Y02B 90/10 : Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 20/10 : Process efficiency
• CPC Class Codes: Y02P 20/141 : Feedstock
• CPC Class Codes: Y02P 20/52 : using catalysts, e.g. selective catalysts

Abstract

Disclosed is a technology based upon the simple nesting of tubes to provide heat exchangers, chemical reactors or chemical reactors with built in heat exchanger. As a chemical reactor, the technology provides the ability to manage the temperature within a process flow to better control the process for improved performance, control the location of product production to control corrosion issue, or implement multiple steps for a process within the same piece of equipment. As a heat exchanger, the technology can provide large surface areas per unit volume and large heat transfer coefficients. As a combined heat exchanger and chemical reactor, the technology can recover the thermal energy from the product flow to heat the reactant flow to the reactant temperature, significantly reducing the energy needs for accomplishment of a process. Combined heat exchanger and chemical reactor examples for hydrogen production and ammonia production are presented, along with a urea production example that integrates the product formation, resonance time conversion and stripping steps for urea production all within a single process unit.

Claims

1. A process for making hydrogen comprising the steps of steam methane reforming and water shift reaction;

using nested-flow technology to maximize the energy utilization, maximize the thermal coupling between the reforming and combustion, and to improve the performance of the catalyst beds.

2. A process for making hydrogen of claim 1, wherein the energy required for heating up the steam and methane reactants is obtained from cooling down the carbon-monoxide, carbon-dioxide and hydrogen products;

wherein the hardware required for that energy transfer is internal to the chemical process reactor; and

wherein a significantly reduction in the energy needs for product formation is observed.

3. A process for making hydrogen of claim 1, wherein the energy required for heating up the combustion reactants is obtained from cooling down the combustion products;

wherein the hardware required for that energy transfer is internal to the chemical process reactor; and

wherein significant increase in the energy available from the combustion process for hydrogen production is observed.

4. A process for making hydrogen of claim 1, wherein the reforming catalyst is situated in such a way that reforming reactants are continuously heated while in the catalyst region to maintain the optimized temperature for hydrogen production.

5. A process for making hydrogen of claim 1, wherein the water shift reaction catalyst is situated in such a way that the water shift reactants temperature is maintained essentially constant in the catalyst region during the exothermic water shift reaction to maintain the optimized temperature for hydrogen production.

6. A process for making hydrogen of claim 1, wherein the combustion reactants are initially pressured to sufficient pressures to accomplish the combustion process within the nested-flow gaps, making available pressurized combustion products for use in other desired processes.

8. A process for making ammonia of claim 6, wherein the energy required for heating up the hydrogen and nitrogen reactants is obtained from cooling down the products, making a significant fraction of the heat of formation of ammonia available at an elevated temperature for other applications.

9. A process for making ammonia of claim 6, wherein the heat of formation during the catalyzed ammonia formation is removed by the nested-flow technology to limit the temperature rise and maximize the fraction of reactants converted to ammonia per pass through the system.

7. A process for making ammonia comprising the steps of the Haber-Bosch process;

using nested-flow technology to maximize the energy utilization and minimizing the physical size of the ammonia production system.

10. A process for making urea comprising of the steps of the Bosh-Meiser process using the nested-flow technology integrating the steps of ammonium-carbamate production, ammonium-carbamate to urea transformation, and ammonium-carbamate from urea stripping all within on nested-flow technology production unit.

11. A process for making urea of claim 10, wherein the carbon-dioxide reactant is used as a sweeping gas to prevent corrosion products from damaging the pressure boundary of the reactor based on the nested-flow paths of the nested-flow technology.

12. A process for making urea of claim 10, wherein the urea/ammonium-carbamate mixture is held at pressure for sufficient time to accomplish significant urea conversion based on the nested-flow paths of the nested-flow technology.

13. A process for making urea of claim 10, wherein the ammonium-carbamate is stripped from the urea/ammonium-carbamate mixture through a counter flow of the gaseous ammonia reactant and liquid urea/ammonium-carbamate mixture.

14. A mobile fertilizer production facility for a production rate of a few 10'"'"'s to tons per day using the nested-flow technology comprising of a nested-flow hydrogen production system, nested-flow ammonia production system and nested-flow urea production system for significant process equipment size reduction.

15. A facility of claim 14, wherein the facility is a net producer of electricity through use of hydrogen fuel cell technology.

16. A heat exchanger comprising of three or more nested tubes for thermal energy transfer from one fluid flow to another fluid flow in which the flow path is maintained open through the use of substantially-non-flow-blocking spacers.

17. A heat exchanger of claim 16, wherein the circular tubes are constructed substantially of metal.

18. A heat exchanger of claim 16, wherein the spacer used to assure flow path integrity is a spiral wire wrap around the outside of any circular tube nested within another circular tube.

19. A heat exchanger of claim 16, wherein more than two fluid flows are engaged in the transfer of thermal energy.

20. A heat exchanger of claim 16, wherein the tube wall thickness is varied with tube diameter to meet operational pressure requirements.

21. A heat exchanger of claim 16, wherein the flow gap is varied as a function of fluid to provide a better system performance.

22. A heat exchanger of claim 16, wherein multiple sets of nested tubes are connected together through the use of manifolds to achieve a total desired flow rate.

23. A chemical reactor comprising of three or more nested tubes to form three or more annular flow paths for processing one or more fluid flow(s) in which the flow path integrity is assured through the use of substantially-non-flow-blocking spacers.

24. A chemical reactor of claim 23, wherein the circular tubes are substantially made of metal.

25. A chemical reactor of claim 23, wherein an exothermic reaction is coupled to an endothermic reaction to substantially negate the energy transfer to-or-from the reactor.

26. A chemical reactor of claim 23, wherein one end of the nested tubes is at a substantially higher temperature than the other and where a substantial fraction of the thermal energy required in raising the reactants temperature to the required operating temperature is obtained from the cooling of the products

27. A chemical reactor of claim 23, wherein a catalyst is utilized within the flow channel to accelerate the rate of product formation.

28. A chemical reactor of claim 23, wherein independent flow channels are provided to inhibit product formation until a specific location has been reached.

29. A chemical reactor of claim 23, wherein the outer tube is made of metal and the inner tubes are made of non-metal to meet corrosion issues during some stage of the chemical process.

30. A chemical reactor of claim 23, wherein the chemical process is essentially some form of combustion and the reactor is configured as a boiler to accomplish a change of state from a liquid to a vapor in a second fluid.

31. A chemical reactor of claim 23, wherein multiple sets of nested circular tubes are connected together with one or more manifold systems to meet quantitative process flow requirements.

32. A chemical reactor of claim 31, wherein a common pressure chamber is incorporated around multiple nested circular tube assemblies to act as a constant temperature heat drain through fluid boiling or a constant temperature source through fluid condensation.