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How do we clean up this mess?

Our patent pending (Indian Patent Application No. 202431028425) Closed-Loop Hybrid Sorbent Carbon Capture and Mineralization process captures CO2 from industrial emissions as solid calcium carbonate (CaCO3) thus doing away the technical, operational and financial bottlenecks associated with capturing CO2 in gaseous form. 

In our process, aqueous solution of NaOH is mixed with CaO powder obtained from industrial waste to form a slurry. This slurry is circulated in a reactor and simultaneously exposed to Flue gases leading to capture of CO2 in the form of CaCO3 while NaOH is regenerated. The slurry is continuously circulated through the reactor as NaOH is regenerated in-situ. CaCO3 is filtered out from the slurry and CaO added  after fixed intervals.  


Value Proposition:


1. Solid State Sequestration of Carbon Dioxide: Capturing CO2 as solid calcium carbonate (CaCO3) presents a promising solution that circumvents numerous challenges associated with capturing CO2 as a gas. Solid CaCO3 not only provides a stable and easily manageable form for storage but also offers a sustainable approach by utilizing natural mineralization processes. This method reduces the risk of CO2 leakage, eliminates the need for complex pressurized storage systems, and minimizes energy-intensive separation processes. Moreover, solid CaCO3 can be utilized in various industrial applications, thereby providing economic incentives for carbon capture efforts.


Existing technologies capture carbon dioxide in gaseous form.


2. No Pipeline or Transportation Constraint: Capturing CO2 as a solid eliminates the need for extensive pipeline infrastructure within plant premises or a nationwide network, making it a highly adaptable solution for regions like India, which are non-gas-based economies. This means that industries can swiftly initiate carbon capture initiatives without the logistical constraints typically associated with gas transport and distribution networks. By enabling immediate deployment, solid capture technologies offer a pragmatic pathway towards sustainable carbon management, aligning with the urgent need for climate action.


3. Continuous Closed-Loop Operation: The ability to regenerate both sorbents (CaO can also be generated by heating CaCO3 at 9000C, if required) ensures a sustainable and continuous operation of the carbon capture system. As the sorbents can be reused in a closed-loop, the need for frequent replacement or disposal is minimized, leading to a more sustainable and environmentally friendly process.


The cyclic nature of the system, with the ability to regenerate both sorbents, promotes long-term stability and reliability. The consistent performance over extended periods enhances the feasibility and practicality of integrating this technology into various industrial processes.


The closed-loop design ensures that no chemicals are discharged or wasted during the process. Instead, all chemicals, including NaOH, Na₂CO₃, and Ca (OH)₂, continually participate in the carbon capture and mineralization process.


4. In-situ Low temperature Sorbent Regeneration: The disclosed invention utilizes a second sorbent (Calcium Oxide, CaO) along with the first (Aqueous Solution of NaOH) to capture carbon dioxide. During the process of carbon capture, the seconds sorbent regenerates the first or primary sorbent in-situ, thereby doing away the need to replace the first sorbent completely, reducing costs and makes the process commercially viable.


5. Hybrid Sorbent: The system utilizes a combination of Solid and Liquid Sorbent. The combination of solid (Calcium Oxide) and liquid (NaOH solution) components enhances the reactivity of the system. This can result in improved efficiency in capturing CO₂ compared to a system relying solely on solid sorbents. The liquid phase provides additional contact points and pathways for CO₂ absorption.


The following reactions happen in the system:


Hydration of CaO: CaO+H2O ➡ Ca (OH)2


Primary Reaction: 2NaOH +CO2 ➡ Na2CO3 + H2O


Secondary Reaction: Ca (OH)2 +CO2 ➡ CaCO3+H2O


Regeneration & Sequestration Reaction: Na2CO3 + Ca (OH)2 ➡CaCO3 +2NaOH


Furthermore, the secondary sorbent, CaO, which in the process is hydrated to Ca(OH)2 generates the primary sorbent, NaOH as per reaction (iv) above and itself gets transformed to Calcium Carbonate, via the same reaction, thereby sequestering CO2 in the solid state.


  1. Low Temperature Process: The system has been so designed that the reactions happen at ambient temperature thereby saving a substantial amount of energy. Generally, carbonation of CaO happen at a temperature over 650 Deg C.

  2. Additional Reaction of Ca(OH)₂: Within the circulating liquid, unreacted Ca(OH)₂ also has the opportunity to react with Na₂CO₃, leading to its conversion into CaCO₃. This dual-reaction mechanism further optimizes the capture process.

  3. No Chemical Separation Required: One of the notable advantages of this system is that there is no need for chemical separation in the circulating liquid as this is a Closed Loop Process. All the chemicals, including NaOH, Na₂CO₃, and Ca(OH)₂, are efficiently utilized within the process. This closed-loop design ensures that no chemical goes to waste, making it a highly resource-efficient and sustainable carbon capture and mineralization solution.

  4. Versatility: The technology can be used in a wide range of applications including Direct-Air-Capture (DAC). The technology can be used to capture CO2 from flue gases coming out of Steel, Power, and Cement Plants.



1. The process is a continuous closed loop system. A closed-loop system offers several advantages that make it favourable for scaling up carbon capture and mineralization technology:

  • Resource Efficiency: In a closed-loop system, the chemicals involved, such as NaOH, Na₂CO₃, and Ca (OH)₂, are continuously circulated and reused. This minimizes chemical waste and ensures efficient utilization of resources, making it cost-effective at scale.

  • Environmental Sustainability: The closed-loop design reduces the environmental impact of the process by preventing the discharge of chemicals into the environment. This aligns with sustainability goals and minimizes potential harm to ecosystems.

  • Consistent Performance: Closed-loop systems provide better control and stability over the reaction conditions. This leads to consistent and predictable performance, which is crucial when scaling up a technology for industrial applications.

  • Reduced Operating Costs: By reusing chemicals, the closed-loop system reduces the need for frequent replenishment of reactants. This leads to cost savings in terms of chemical procurement and handling.

  • Minimized Waste Management: With no chemical discharge, waste management becomes less complex. This simplifies regulatory compliance and lowers costs associated with waste disposal.

  • Enhanced Carbon Capture Efficiency: The continuous circulation of chemicals ensures that carbon capture reactions remain active and efficient. Unreacted Ca(OH)₂, for example, gets additional opportunities to react with CO₂, maximizing carbon capture efficiency.

  • Flexibility: Closed-loop systems can be adapted and fine-tuned for various applications and industries. Their flexibility makes them suitable for addressing diverse carbon capture challenges.

  • Continuous Operation: Your system operates continuously, allowing for a steady flow of captured CO₂ and minerals. This continuous operation minimizes downtime and enhances overall efficiency, making it well-suited for large-scale applications.


2. Hybrid Sorbent System: The combination of solid sorbent (CaO) and liquid sorbent (NaOH) in your system provides flexibility and adaptability. This hybrid approach allows for optimization based on the specific requirements of different industries and processes, making it versatile for scaling to various applications.


3. Single Cycle Process: The process involves only a single cycle making the process simple, less capital intensive and scalable.


4. Low-Temperature Operation: Operating at lower temperatures than traditional carbon capture methods can reduce energy requirements. This energy-efficient characteristic is valuable for scaling up because it can lead to lower operational costs when capturing CO₂ at a larger scale.


5. Minimized Chemical Handling: The closed-loop system reduces the need for extensive chemical handling and storage, which can become a logistical challenge at a larger scale. This simplifies the management of chemicals, making scaling up more feasible.


6. Minimal Waste Stream: Your system minimizes waste generation since most chemicals are continuously reused. This reduces the need for extensive waste treatment facilities, simplifying the scaling process.


7. Ease of Integration: The system's design allows for straightforward integration into existing industrial processes. This ease of integration is advantageous when adapting the technology for various industries and sectors.


8. Potential for Modular Design: The closed-loop and continuous operation aspects of your system make it amenable to modular design. Multiple reactor units can be added to scale up capacity incrementally, making it a flexible approach for large-scale deployment.


9. Environmental Benefits: The closed-loop design and efficient use of resources align with sustainability goals and environmental regulations. This can facilitate regulatory approvals and public acceptance when scaling up in different regions.


These attributes collectively make this carbon capture and mineralization technology well-suited for large-scale applications, providing advantages in terms of efficiency, adaptability, and environmental sustainability compared to some other carbon capture systems.

Write to us to know more about how our technology can help you simultaneously reduce and remove your emissions and our unique deployment model that will help you attain net-zero emissions. 

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