Appendix A
Glossary
Term | Explanation |
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Atom economy | The percentage of atoms in the starting reagents which are converted to product. A measure of the amount of waste products that are generated. Formally defined as atom economy = (molecular mass of product)/(molecular mass of all starting reagents) * 100. |
Bench scale | A stage of commercialization where critical functions are proved and components or systems are validated in a laboratory environment and at a laboratory scale. |
Biological utilization | Conversion of gaseous carbon wastes through biological processes. |
Carbon capture | Carbon dioxide is captured at its point of production and separated from other by-products of fossil fuel combustion, compressed, and transported in a pipeline either for utilization or sequestration. |
Carbon dioxide removal | The objective is large-scale removal of carbon dioxide from the atmosphere. Carbon dioxide removal approaches considered by the committee are coastal and land ecosystem management, accelerated weathering, bioenergy with carbon capture, direct air capture, and geologic sequestration. |
Carbon utilization | The manufacture of valuable products from a gaseous carbon waste feedstock (carbon dioxide and methane) that results in a net reduction of greenhouse gases emitted to the atmosphere. |
Chemical utilization | Conversion of gaseous carbon wastes through chemical processes. |
Circular carbon economy | An industrial carbon-based system that is restorative or regenerative by intention and design. |
Commercial–broad | A stage of commercialization where a product is manufactured in such a way that it does not rely on local environmental, regulatory, or other factors. |
Commercial–limited | A stage of commercialization where a product is manufactured in an area with specific advantages that make it viable due to the local environmental, regulatory, or other factors. |
Term | Explanation |
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Conversion | The amount of the starting material which is consumed in a reaction. Typically expressed as a percentage and defined as conversion = {1 − (amount of starting material at end of reaction)/(initial amount of starting material)} * 100. |
Demonstration scale | A stage of commercialization where a full-scale system is demonstrated in a relevant environment. |
Disruptive change | A change that creates a new market and value network that disrupts an existing market and value network. |
Economic value | A measure of the benefit provided by a good or service to an economic agent. |
Enabling resources | Resources such as hydrogen, electricity, and heat needed for carbon utilization. |
Enabling technologies | Technologies such as transportation infrastructure and separations methods required for carbon utilization. |
Energetic efficiency | The ratio, expressed as a percentage, of theoretical energy required (standard reduction / oxidation potential) multiplied by Faradaic efficiency to the actual energy required (standard reduction / oxidation potential plus overpotential). For an electrochemical process, the energetic efficiency is calculated by summing the energetic efficiencies of all reactions involved at the cathode and the anode. |
Energy requirement | The amount of energy per mole or per mass of product needed to drive an electrochemical conversion (including the energy needed in excess of the thermodynamic minimum required), also accounting for parasitic reactions (e.g., hydrogen evolution at the cathode, oxygen evolution at the anode). |
Faradaic efficiency | In electrochemistry the efficiency with which electrons that are introduced into the reaction are converted into a specific product. Typically expressed as a percentage. |
Fundamental research | A stage of commercialization where fundamental principles of a scientific or engineering process are observed and reported, and a technology concept is formed. |
Gaseous carbon waste streams | Carbon dioxide, methane, or biogas that is present in a waste gas stream. |
Life-cycle assessment | A technique used to catalog energy, water, and materials (e.g., chemicals, metals) inputs, outputs, and emissions over the life cycle of a process or product. |
Long-lived | Carbon waste is not emitted through use of the product for a period of more than 100 years. |
Term | Explanation |
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Low or zero carbon | A property of a process which describes the emissions attributed to the process. Low carbon means producing fewer carbon compounds such as carbon dioxide that might contribute to pollution than similar technologies. Zero carbon means the process is not associated with net emission of carbon wastes to the atmosphere. The terms carbon free, low carbon, and carbon neutral are each synonymous with the spectrum of properties described as low or zero carbon. |
Mineral carbonation | Formation of carbonates by contacting alkaline solids, often in an aqueous suspension, with carbon dioxide in a fluid state. In the context of this study, mineral carbonation refers to forming a useful product, rather than related chemical processes to sequester carbon in the form of natural carbonates. |
Overpotential | In electrochemistry the difference in potential between the thermodynamically determined reduction potential of a half-reaction and the potential at which the half-reaction is observed experimentally. |
Pilot scale | A stage of commercialization where a system validated in a relevant environment and at an engineering scale. |
Selectivity | The amount of the converted starting material which forms the desired product. Typically expressed as a percentage and defined as selectivity = (amount of product)/(amount of conversion of starting material) * 100. |
Sequestration | Carbon dioxide trapped for more than 100 years. |
Short-lived | Carbon waste is emitted through use or disposal of the product in less than 100 years. |
Storage | Carbon dioxide trapped for 100 years or less. |
Technoeconomic analysis | A tool that is widely used in industry to evaluate commercial viability of any new technology. |
Turnover frequency (TOF) | In a catalytic reaction the number of moles of product produced per mole of catalyst per unit of time. |
Turnover number (TON) | In a catalytic reaction the number of moles of product produced per mole of catalyst. |
Valorization | A process which enhances the value of a material by transforming it into a product. |
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