Derivative works — US Patent 11673805

Defensive Disclosure: US Patent 11673805

This document outlines derivative variations and extensions of the processes and plants described in US Patent 11673805, aimed at establishing prior art for future incremental improvements by competitors. These disclosures cover material and component substitutions, operational parameter expansions, cross-domain applications, integration with emerging technologies, and inverse or failure modes of the invention.

Derivative Variations

1. Material & Component Substitution

Derivative 1.1: Advanced Catalysts for Reforming and Water-Gas Shift (WGS)

Enabling Description: The nickel-based reforming catalyst specified in claim 1(b) is substituted with bimetallic catalysts comprising noble metals such as Ruthenium (Ru) or Rhodium (Rh) supported on ceramic carriers like Alumina (Al₂O₃) or Zirconia (ZrO₂). These catalysts are designed for enhanced activity and coking resistance, allowing lower steam-to-carbon ratios and reduced operating temperatures in the endothermic reforming unit 200 while maintaining high methane conversion. Similarly, the suitable catalyst for the CO conversion in step (d) is replaced with a low-temperature shift (LTS) catalyst incorporating copper-zinc-aluminum oxide (Cu/ZnO/Al₂O₃) formulations, optimized for maximum CO conversion at temperatures between 180° C. and 250° C., thereby minimizing unconverted carbon monoxide in synthesis gas stream SG4.
Specific Technical Terminology: Bimetallic catalysts, Ruthenium/Rhodium-on-Alumina (Ru/Al₂O₃, Rh/Al₂O₃), Zirconia support, coking resistance, steam-to-carbon ratio, Low-Temperature Shift (LTS), Cu/ZnO/Al₂O₃ catalyst, CO conversion efficiency.

graph TD
    A[Feed Gas FG] --> B{Pre-Reformer (Optional)}
    B --> C{Bimetallic Reforming Unit (Endothermic)}
    C -- Heat Flow 202 (SG2/SG3) --> D{Autothermal Reforming Unit (ATR)}
    D -- SG2/SG3 Stream --> C
    C -- SG1 --> E[Mixer]
    D -- SG2 (Parallel) --> E
    E -- SG3 --> F{LTS Converter Unit}
    F -- SG4 --> G[PSA Unit]
    G -- HG1 --> H[Pure H2 Product]
    G -- RG1 --> I[Cryogenic CO2 Separation]
    I -- CG1 --> J[Liquid CO2 Product]
    I -- RG2 --> K[Further Separation / Fuel]

Derivative 1.2: Metal-Organic Frameworks (MOFs) as PSA Adsorbents

Enabling Description: The pressure swing adsorption unit 204 (claim 1(e)) utilizes Metal-Organic Frameworks (MOFs), specifically Cu-BTC (HKUST-1) or UiO-66 derivatives, as the adsorbent material for hydrogen purification. These MOFs possess highly selective adsorption characteristics for CO and CO₂ over hydrogen, operating typically at adsorption pressures between 10-40 bar and regeneration (desorption) pressures between 0.1-5 bar, with cycle times ranging from 60 seconds to 5 minutes. This allows for improved hydrogen recovery and higher purity (e.g., >99.999% H₂) compared to conventional adsorbents like activated carbon or zeolites, while also reducing the volume of the first residual gas stream RG1.
Specific Technical Terminology: Metal-Organic Frameworks (MOFs), Cu-BTC (HKUST-1), UiO-66, selective adsorption, pressure swing adsorption (PSA), regeneration pressure, cycle time, hydrogen purity, activated carbon, zeolites.

graph TD
    A[SG4 from Converter] --> B{MOF-based PSA Unit (Adsorption)}
    B -- Pure H2 (HG1) --> C[H2 Product Storage]
    B -- Impurities (CO, CO2, CH4) --> D{MOF-based PSA Unit (Desorption/Regeneration)}
    D -- Regenerated Adsorbent --> B
    D -- Residual Gas (RG1) --> E[Cryogenic CO2 Separation]
    E -- CG1 --> F[CO2 Product]
    E -- RG2 --> G[Fuel/Further Processing]

2. Operational Parameter Expansion

Derivative 2.1: Microreactor-based Distributed Hydrogen Production

Enabling Description: The endothermic reforming step (claim 1(b)) and the autothermal reforming step (claim 1(c)) are performed in a network of microreactors, each with characteristic dimensions in the sub-millimeter range. This configuration dramatically increases the surface area-to-volume ratio, facilitating rapid heat transfer and enabling highly intensified reactions. The microreactors operate at significantly higher mass transfer rates and potentially higher partial pressures (e.g., local pressures up to 70 bar, with overall system pressures similar to or slightly higher than conventional, 40-60 bar) and optimized temperature profiles tailored to micro-scale kinetics, for example, 800-900° C. for endothermic reforming. This distributed approach supports on-site, modular hydrogen production, reducing transportation costs and enhancing safety by minimizing large-scale equipment.
Specific Technical Terminology: Microreactor technology, surface area-to-volume ratio, intensified reactions, mass transfer rates, modular production, distributed hydrogen generation, optimized temperature profiles, micro-scale kinetics.

graph TD
    A[Feed Gas FG] --> B(Microreactor Manifold)
    B --> C{Endothermic Microreformer Array}
    B --> D{Autothermal Microreformer Array}
    D -- Heat Exchange Channels --> C
    C -- SG1 --> E[Micro-Mixer]
    D -- SG2 (Parallel) --> E
    E -- SG3 --> F[Miniaturized WGS Unit]
    F -- SG4 --> G[Compact PSA Unit]
    G -- HG1 --> H[Local H2 Dispenser]
    G -- RG1 --> I[Mini-Cryogenic CO2 Separator]
    I -- CG1 --> J[Local CO2 Storage/Use]
    I -- RG2 --> K[Recycle/Combust]

Derivative 2.2: Ultra-High Pressure Reforming and Water-Gas Shift

Enabling Description: The entire reforming (endothermic and autothermal, steps (b) and (c)) and CO conversion (WGS, step (d)) sections of the process are designed to operate at significantly elevated pressures, specifically ranging from 100 bar to 200 bar. This ultra-high pressure operation directly increases the partial pressures of reactants, accelerating reaction rates and shifting equilibrium towards product formation (hydrogen and carbon dioxide). The endothermic reforming unit 200 and autothermal reforming unit 201 are constructed with advanced high-strength alloys (e.g., Incoloy 800HT or equivalent for reformer tubes, pressure vessel steels for ATR) to withstand these pressures. The downstream PSA (step (e)) and cryogenic CO2 separation (step (f)) benefit from reduced compression requirements for product recovery and liquefaction, as the streams are already at a high baseline pressure.
Specific Technical Terminology: Ultra-high pressure operation, partial pressure, reaction kinetics, equilibrium shift, high-strength alloys, Incoloy 800HT, compression energy, liquefaction.

graph TD
    A[Feed Gas FG (100-200 bar)] --> B{Ultra-High Pressure Endothermic Reforming}
    B -- Heat from C --> C{Ultra-High Pressure Autothermal Reforming}
    C -- SG2/SG3 --> D{Ultra-High Pressure WGS Converter}
    B -- SG1 (Parallel) --> D
    D -- SG4 --> E[High-Pressure PSA]
    E -- HG1 --> F[High-Pressure H2 Product]
    E -- RG1 --> G[High-Pressure Cryogenic CO2 Sep.]
    G -- CG1 --> H[High-Pressure CO2 Product (Liquid)]
    G -- RG2 --> I[Fuel/Disposal]

3. Cross-Domain Application

Derivative 3.1: Martian In-Situ Resource Utilization (ISRU) Hydrogen and Carbon Dioxide Production

Enabling Description: The process for preparing hydrogen and separating carbon dioxide is adapted for Martian in-situ resource utilization (ISRU). A Martian atmospheric feed gas (primarily CO₂, with trace N₂, Ar) is combined with imported or in-situ produced water via the Sabatier reaction (CO₂ + 4H₂ → CH₄ + 2H₂O) or reverse water-gas shift (RWGS) to produce methane as the hydrocarbon feedstock. The methane/steam mixture is then fed into compact, radiation-hardened reforming units (endothermic and autothermal) using a robust, low-temperature-activation catalyst (e.g., ceria-zirconia supported Ru). The heat integration between the ATR and endothermic reformer is crucial for energy efficiency in a resource-constrained environment. The separated hydrogen is liquefied for rocket propellant, and the captured CO₂ is either stored or used for further synthesis (e.g., oxygen production via electrolysis). The entire plant, per claim 12, is miniaturized and designed for autonomous operation under Martian atmospheric and gravitational conditions.
Specific Technical Terminology: Martian In-Situ Resource Utilization (ISRU), Sabatier reaction, reverse water-gas shift (RWGS), radiation-hardened, low-temperature-activation catalyst, ceria-zirconia supported Ru, compact reforming units, autonomous operation, rocket propellant, oxygen production.

graph TD
    A[Martian Atmosphere (CO2, N2)] --> B{Sabatier/RWGS Reactor}
    B -- CH4, H2O --> C[Feed Gas FG (Martian)]
    C --> D{Endothermic Reforming (Martian-optimized)}
    C --> E{Autothermal Reforming (Martian-optimized)}
    E -- Heat Flow --> D
    D -- SG1 --> F[Mixer]
    E -- SG2 (Parallel) --> F
    F -- SG3 --> G[CO Conversion (Martian-optimized)]
    G -- SG4 --> H[PSA Unit (Martian-optimized)]
    H -- HG1 (H2) --> I[H2 Liquefaction / Propellant]
    H -- RG1 --> J[Cryogenic CO2 Sep. (Martian-optimized)]
    J -- CG1 (CO2) --> K[CO2 Storage / Electrolysis]
    J -- RG2 --> L[Recycle / Vent to Atmosphere]

Derivative 3.2: Waste-to-Hydrogen Production from Gasified Biomass Syngas

Enabling Description: The process is adapted to use synthesis gas derived from the gasification of biomass or municipal solid waste (MSW) as the primary hydrocarbon feedstock. This syngas, containing methane, carbon monoxide, hydrogen, and various impurities, is first cleaned and then fed to the combined endothermic and autothermal reforming units. Instead of natural gas, the "feed gas stream FG" (claim 1(a)) comprises pre-treated syngas. The autothermal reforming step is critical for handling variations in syngas composition and providing the necessary heat balance. The subsequent WGS, PSA, and cryogenic CO₂ separation steps function as described, producing renewable hydrogen ("green hydrogen") and capturing biogenic CO₂. This application contributes to waste valorization and circular economy principles.
Specific Technical Terminology: Biomass gasification, municipal solid waste (MSW), syngas, waste valorization, renewable hydrogen, biogenic CO₂, circular economy, pre-treatment, autothermal reforming.

graph TD
    A[Biomass/MSW] --> B{Gasifier}
    B -- Raw Syngas --> C{Syngas Cleaning Unit}
    C -- Clean Syngas FG --> D{Endothermic Reforming (Syngas-adapted)}
    C -- Clean Syngas FG --> E{Autothermal Reforming (Syngas-adapted)}
    E -- Heat Flow --> D
    D -- SG1 --> F[Mixer]
    E -- SG2 (Parallel) --> F
    F -- SG3 --> G[WGS Unit]
    G -- SG4 --> H[PSA Unit]
    H -- HG1 --> I[Green H2 Product]
    H -- RG1 --> J[Cryogenic CO2 Separation]
    J -- CG1 --> K[Biogenic CO2 Storage/Use]
    J -- RG2 --> L[Fuel/Recycle to Gasifier]

4. Integration with Emerging Tech

Derivative 4.1: AI-Driven Real-time Process Optimization

Enabling Description: An Artificial Intelligence (AI) system, specifically a deep reinforcement learning (DRL) agent, is integrated to optimize the operation of the process in real-time. IoT sensors (e.g., gas chromatographs, temperature/pressure transducers, flow meters) continuously feed data on feed gas composition (FG), synthesis gas streams (SG1-SG4), and residual gas streams (RG1-RG3) into the AI platform. The DRL agent, trained on simulation models and historical plant data, dynamically adjusts operational parameters such as steam-to-carbon ratio, oxygen-to-carbon ratio in ATR, reforming temperatures, WGS reactor temperatures, PSA cycle times, and cryogenic cooling rates. The objective function for the AI is to minimize specific CO₂ emissions (kg CO₂/m³ H₂) and maximize hydrogen purity (HG1) and yield, while ensuring safe operating limits and adapting to fluctuating natural gas supply quality or hydrogen demand.
Specific Technical Terminology: Artificial Intelligence (AI), deep reinforcement learning (DRL), IoT sensors, gas chromatograph, real-time optimization, steam-to-carbon ratio, oxygen-to-carbon ratio, PSA cycle times, cryogenic cooling rates, specific CO₂ emissions, hydrogen purity, dynamic control.

graph TD
    A[Feed Gas FG] --> B{Reforming Units (Endo + Auto)}
    B -- SG3 --> C{WGS Unit}
    C -- SG4 --> D{PSA Unit}
    D -- RG1 --> E{Cryogenic CO2 Separation}
    E -- RG2 --> F{Membrane Unit (Optional)}
    F -- RG3 --> G{Further Processing/Fuel}

    H[IoT Sensor Network] -- Real-time Data --> I(AI Optimization Platform)
    I -- Control Signals --> B
    I -- Control Signals --> C
    I -- Control Signals --> D
    I -- Control Signals --> E
    I -- Control Signals --> F

    J[Hydrogen Demand] --> I
    K[Feedstock Cost/Availability] --> I
    L[CO2 Emissions Target] --> I

Derivative 4.2: IoT-Enabled Predictive Maintenance for Catalyst and Heat Exchangers

Enabling Description: The plant components, particularly the endothermic reforming unit 200, autothermal reforming unit 201, and associated heat exchangers (involved in heat flow 202), are equipped with a comprehensive array of Internet of Things (IoT) sensors. These sensors monitor localized temperatures (e.g., thermocouple arrays inside reformer tubes), pressure drops across catalyst beds, acoustic emissions (for detecting micro-cracks in ceramic components), and real-time gas composition analysis (ee.g., via micro-GC or tunable diode laser spectroscopy). Data is transmitted wirelessly to a cloud-based analytics platform that employs machine learning algorithms for predictive maintenance. By analyzing trends in pressure drop, temperature gradients, and minor changes in product gas composition (e.g., slight increase in unreacted methane), the system predicts catalyst coking, sintering, or poisoning, and heat exchanger fouling or leakage, well in advance of critical failure. This enables scheduled, optimized maintenance interventions, minimizing downtime and maximizing operational efficiency.
Specific Technical Terminology: Internet of Things (IoT) sensors, thermocouple arrays, pressure drop, acoustic emissions, micro-GC, tunable diode laser spectroscopy (TDLAS), cloud-based analytics, machine learning algorithms, predictive maintenance, catalyst coking, sintering, poisoning, heat exchanger fouling, operational efficiency.

graph TD
    A[Feed Gas FG] --> B{Endothermic Reforming Unit 200}
    A --> C{Autothermal Reforming Unit 201}
    C -- Heat Flow 202 --> B

    B -- Sensor Data (Temp, Pressure, Comp) --> D(IoT Gateway)
    C -- Sensor Data (Temp, Pressure, Comp) --> D
    B -- SG1 --> E[WGS, PSA, Cryo Sep.]
    C -- SG2/SG3 --> E

    D -- Wireless Transmission --> F[Cloud Analytics Platform]
    F -- Machine Learning Models --> G(Predictive Maintenance System)
    G -- Maintenance Alerts/Recommendations --> H[Maintenance Crew / Control System]

5. The "Inverse" or Failure Mode

Derivative 5.1: Controlled Low-Power Standby and Safe Flaring/Recycling

Enabling Description: The process includes a controlled "low-power standby" or "limited-functionality" mode designed for safe operation during periods of low hydrogen demand, grid instability, or minor equipment malfunctions. In this mode, the feed gas stream FG (claim 1(a)) flow to the reforming units 200 and 201 is significantly reduced (e.g., to 10-20% of nominal capacity) or completely halted. If reforming is active at a reduced rate, the resulting synthesis gas stream SG3 is not processed through the full chain of WGS, PSA, and cryogenic separation. Instead, it is routed to an emergency flare stack for safe combustion (e.g., during critical failure) or, more preferentially, recycled upstream (e.g., to feed gas compression or the ATR unit as supplementary fuel) for energy recovery, ensuring that no off-specification hydrogen or partially separated CO₂ is produced or released unintentionally. Safety interlocks automatically trigger this mode upon detecting critical alarms or a predefined low-demand threshold.
Specific Technical Terminology: Low-power standby, limited-functionality mode, emergency flare stack, safe combustion, upstream recycle, energy recovery, off-specification product, safety interlocks, critical alarms, demand threshold.

stateDiagram-v2
    [*] --> Operational
    Operational --> LowPower: Low H2 Demand / Minor Fault
    LowPower --> Operational: Demand Recovery / Fault Cleared
    LowPower --> EmergencyShutdown: Critical Fault / Safety Breach
    Operational --> EmergencyShutdown: Critical Fault / Safety Breach
    EmergencyShutdown --> [*]

    state Operational {
        FeedGas --> Reforming --> WGS --> PSA --> CryoSep
        CryoSep --> H2Product & CO2Product
    }
    state LowPower {
        FeedGasReduced --> ReformingReduced
        ReformingReduced --> FlareOrRecycle
    }
    state EmergencyShutdown {
        FeedGasCutoff
        SystemPurge
        SafetyValveActuation
    }

Derivative 5.2: Tailored Process for High-Purity CO₂ Production with Co-Generated Hydrogen for Enhanced Oil Recovery (EOR)

Enabling Description: The primary objective of the process is shifted from hydrogen production to maximizing the yield and purity of the carbon dioxide-rich stream CG1 (claim 1(f)) for use in Enhanced Oil Recovery (EOR) or direct carbon sequestration. While hydrogen is still produced, its purity and quantity are optimized as a valuable co-product rather than the sole output. The process parameters, including steam-to-carbon ratio in reforming, WGS temperature profiles, and especially the cryogenic CO₂ separation unit (step (f)), are tuned for aggressive CO₂ capture and purification (e.g., >99.9% CO₂ purity, with minimal methane and H₂S impurities, potentially incorporating additional selective scrubbing steps before or after cryogenic separation). The co-generated hydrogen (HG1) can be entirely consumed internally as fuel for the ATR or other utility heating, or exported for other industrial uses, but the design prioritizes CO₂ capture efficiency and purity for geological storage or EOR injection.
Specific Technical Terminology: Enhanced Oil Recovery (EOR), carbon sequestration, co-product, aggressive CO₂ capture, CO₂ purity, methane impurities, H₂S impurities, selective scrubbing, geological storage, ATR fuel.

graph TD
    A[Feed Gas FG] --> B{Reforming (Endo + Auto) - CO2 Opt.}
    B -- SG3 --> C{WGS Unit - CO2 Opt.}
    C -- SG4 --> D{PSA Unit - CO2 Co-Gen H2}
    D -- HG1 (Co-gen H2) --> E[Internal Fuel / Other Use]
    D -- RG1 --> F{Cryogenic CO2 Separation (High Purity)}
    F -- CG1 (High Purity CO2) --> G[CO2 Compressor / EOR Injection / Sequestration]
    F -- RG2 --> H[Fuel / Further Processing]

Combination Prior Art Scenarios with Open-Source Standards

These scenarios demonstrate how the inventive process of US11673805 could be combined with established open-source or industry standards, thereby potentially rendering future modifications obvious.

1. Integration with IEC 61508 for Functional Safety:

Scenario: The plant for hydrogen production and carbon dioxide separation described in US11673805, involving high-temperature reforming, high-pressure gas streams, and handling of flammable hydrogen and inert CO₂, is implemented with a Safety Instrumented System (SIS) designed and verified according to IEC 61508 (Functional safety of electrical/electronic/programmable electronic safety-related systems). This involves designing the control architecture, selecting safety-certified sensors (e.g., for H₂ leaks, overpressure in reforming units, critical temperature deviations), actuators (e.g., emergency shutdown valves for feed gas), and logic solvers (e.g., PLCs) to achieve specific Safety Integrity Levels (SILs). This combination discloses applying established functional safety principles to the inherently hazardous components of hydrogen production and CO₂ capture, covering the entire process from feed gas supply to product delivery and waste gas handling.

2. Application of OPC UA for Industrial Data Exchange:

Scenario: The various units of the plant described in US11673805—specifically the endothermic reforming unit, autothermal reforming unit, water-gas shift converter, pressure swing adsorption unit, and cryogenic CO₂ separation unit—are configured to communicate and exchange data using the OPC Unified Architecture (OPC UA) standard. Each unit exposes its operational parameters (temperatures, pressures, flow rates, gas compositions, catalyst health indicators) and control interfaces via OPC UA information models. This enables seamless, secure, and vendor-agnostic interoperability for real-time monitoring, historical data logging, and control by a centralized Distributed Control System (DCS) or an external AI-driven optimization platform (as described in Derivative 4.1). This combination establishes prior art for a highly interconnected and standardized data infrastructure for this type of hydrogen and CO₂ production process.

3. Compliance with ISO 14064 for Greenhouse Gas Accounting and Verification:

Scenario: The process of US11673805, particularly focusing on the separation of carbon dioxide (step (f)) and its potential for sequestration or utilization, is implemented with a comprehensive framework for quantifying, monitoring, reporting, and verifying greenhouse gas (GHG) emissions and removals in accordance with ISO 14064 (Greenhouse gases – Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals; Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements; Part 3: Specification with guidance for the validation and verification of greenhouse gas assertions). This involves detailed measurement of CO₂ streams (FG, SG1-SG4, RG1-RG3, CG1), energy consumption, and fuel usage throughout the plant to accurately calculate the "specific carbon dioxide emission" (as presented in the patent's examples) and ensure that the captured CO₂ meets the criteria for carbon credits or environmental compliance. The combination demonstrates the application of internationally recognized standards for transparent and verifiable carbon management within this specific hydrogen production and CO₂ capture process.