Frequently Asked Questions
Q. What is MAP?
A. MAP stands for Mineralization via Aqueous Precipitation. Calera is able to form specific carbonate minerals that can be formed into cements, supplementary cementitious materials, and synthetic limestone which is useful as aggregate. The MAP process removes dissolved ions from natural waters like seawater or geologic formation waters, producing softened water that can be economically desalinated.
Q. Can the carbon dioxide escape?
A. Calera converts carbon dioxide to carbonates. The three species of carbonate produced are carbonic acid, bicarbonate, and carbonate. Strongly acidic conditions or very high heat are required for the carbon dioxide to escape from these forms. All of the applications of MAP technology leave the converted carbon in the stable and permanent carbonate state where carbon dioxide will never likely be released.
Q. What is unique about Calera’s technology?
A. The Calera technology is a portfolio of patented technologies associated with the carbon conversion and mineralization of carbon dioxide (CO2) in the form of carbonate and subsequent conversion to building materials. Also included is the high efficiency production of alkalinity using a low voltage base production technology. Calera pioneered these developments at its state-of-the-art laboratories in Los Gatos, California and scaled the technology to pilot scale and demonstration scale in Moss Landing, California.
Q. What are the inputs to the Calera process?
A. The inputs are a source of carbon dioxide, a source of water, a source of alkalinity and a source of divalent cations.
Q. How much alkalinity is required and what is the source?
A. The amount of alkalinity required depends on the particular site location specifics and the carbonate species that is required for the local market. Some applications require no alkalinity beyond the available alkalinity already present in the site by products; others require one equivalent of alkalinity per carbon dioxide molecule in the case of bicarbonate products, still others require two units of alkalinity per carbon dioxide molecule converted in the case of carbonate products. Calera has developed techniques to secure useful alkalinity from a number of sources of material, including alkaline surface waters, certain types of natural geologic brines and minerals, and solid industrial effluents or byproducts such as fly ash from coal fired boilers, cement kiln dust, iron smelter residue, aluminum anodization byproducts, and paper mill effluent. If insufficient alkalinity is available for the particular production plan from these sources, the alkalinity is produced from a proprietary technology known as ABLE (Alkalinity Based on Low Energy) that uses only salt water and electricity as inputs.
Q. What is the source of divalent cations?
A. Divalent cations are principally calcium and magnesium that can be abundant in natural waters. These ions are what is known as the hardness of the water. "Hard" water has a large number of these ions. According to the USGS Produced Water database, a significant fraction of the waters currently produced from oil production have calcium concentrations greater than 20,000 ppm. Calcium enriched brines are formed by several natural processes that are well known to geochemists. Hard brines can also be supplied from man-made sources, such as desalination concentrates, fracking waters from tight shales, and other produced waters from oil and gas fields. Calcium and magnesium are also present in solid waste products as well as in many naturally occuring minerals such as gypsum & mafic minerals, fly ash and cement kiln dust.
Q. Will the Calera process only work with seawater?
A. This is a common misconception, due to the fact that Calera’s initial process was demonstrated at a site in California where seawater was used as one of the potential sources of divalent cations. The Calera process is well suited to locations that do not have access to seawater. In fact, it is easier to use waters such as geologic brines due to the significantly higher concentration of calcium than in seawater. The testing at laboratory, pilot scale and demonstration scale has proven the robustness and flexibility of the MAP process to effectively use a variety of hard water and alkalinity sources.
Q. What products does Calera produce?
A. The outputs from the Calera process are clean air, calcium carbonate, and chemicals. If the proprietary low voltage electrochemical process is required for additional alkalinity, hydrochloric acid or alternative byproducts will also be produced.
Q. What will happen to the hydrochloric acid?
A. The hydrochloric acid can be sold on the open market for industrial uses, used internally to extract divalant cations from solid soures, used for oil well or brine production, or injected in deep geologic reservoirs. Calera is also continuing to innovate new tehcnologies which do not produce acid products.
Q. Are there chlorides in the Calera products?
A. No. The concrete building code produced by the American Concrete Institute (ACI 318) strictly limits the amount of chloride ion contained in concrete. This restriction is intended to protect the reinforcing steel in concrete from chloride-induced corrosion.
The limits on chloride content apply to all potential sources within the concrete including cementitious materials (SCMs) and aggregates. Calera is aware of these limits and includes steps in the manufacturing process to reduce and maintain the chloride content of our products to acceptable limits.
Q. What is the carbon footprint of your product?
A. All Calera building materials contain embodied CO2. The products contain carbon that would have been emitted from a stationary point source, and there is also an offset of the avoided carbon emission from the traditional techniques used to generate the building materials; i.e. the cement plant emissions. The ultimate goal is to produce products that are carbon negative, and as we scale up and refine our technology, that remains in the forefront.
Q. Have you verified the “carbon capture” of your products?
A. Yes, using stable isotopic methods we have verified the “carbon content” of our products and have also confirmed that the carbon captured originated from the flue gas source (as opposed to atmospheric CO2).
Q. Where will you sell your products?
A. Our products will, in most cases, be sold and distributed in markets in close proximity to the flue gas CO2 sources i.e. close to the power or industrial plants. Large power plants are typically located close to big population centers, which provide a large product market.
Q. When can we expect to see an actual Calera cement?
A. Initially we are focused on the production of supplementary cementitious products to make carbon embodied concrete for use in non-structural applications. These materials are currently being produced in large (ton) quantities at Mos sLanding, and are being used in construction demonstration projects.
Q. Can the Calera process handle the other pollutants in a typical coal flue gas such as mercury?
A. At the pilot plant at Moss Landing, we have evaluated the flu gas emissions from several different coal types from a coal-fired boiler simulator and can confirm that most of the other pollutants (e.g. SOx, other acid gases, and mercury) present in the flue gas are removed at very high efficiencies.
Q. What percentage of the CO2 in a typical flue gas can the Calera process capture?
A. At our Moss Landing 10 MW demonstration absorption unit, we have proven 86% capture of the CO2 from a flue gas slip-stream from Dynegy’s adjacent gas powered power plant. We have also achieved similar capture percentages from the flue gas from our pilot size coal combustion test unit.
Q. When are you going to prove that your process works at coal-fired power plant?
A. We have a coal combustion unit in our Moss Landing pilot plant, and results from this were used to successfully design our demonstration plant at a scale up factor of 100 fold. We are also working with several U.S. coal power companies with the support of the DOE.
Q. Do Calera building materials meet the ASTM standards?
A. Yes, our intent is to meet the current ASTM standards for building materials and the EPA standards for water products. All our tests on samples have demonstrated that our products are comparable to traditional concrete products and have been externally validated by third party independent labs. Continuous testing to these industry standards will be carried out as we scale up our process to full commercial scale.
Q. Is the Calera process scalable?
A. We are currently operating a demonstration plant in Moss Landing, California to determine the commercial scale processing and energy requirements for the removal of carbon dioxide from power plant flue gas. The Demonstration Plant removes carbon dioxide from a slipstream of the flue gas produced by the adjacent Dynegy Moss Landing natural gas fired combined cycle power plant. The design rate of flue gas flow that can be processed in the Demonstration Plant, approximately 20,000 standard cubic feet per minute, is equivalent to approximately 10 MW of electrical power from a coal-fired plant. We have proven, and the engineering firm RW Beck has independently verified, that we met our goal of a minimum of 80 percent carbon dioxide removal with less than 10 percent power consumption. We have successfully designed the Demonstration Plant and the supporting equipment with sufficient flexibility in testing equipment components and operating conditions such that we are able to select and then confirm or subsequently modify promising internal configurations and operating conditions that ultimately lead to producing “best” results. The scale of the Demonstration Plant is sufficiently large that any issues specific to large scale can be observed and corrected. The Demonstration Plant also has sufficient flexibility in the scrubber liquid preparation area to allow Calera to test synthetic versions of the brines and base sources that we will use commercially.
Q. Are there major risks associated with the scale up of your process technology?
A. Calera, as with any new technology, will face challenges, but overall, the risk is lower than that related to other carbon capture approaches. Ian Copeland, President of Bechtel Renewables and New Technology, said about Calera in a recent press release; “While there are challenges to bringing the Calera process to commercial scale, they are not as great as those facing other carbon sequestration approaches." We anticipate that the process technology will be scaled progressively to larger scale at various demonstration sites. The ultimate scale of projects will be dictated by access to input feedstock and out put market demand.
Q. Some skeptics of the Calera process say this has been tried before and does not work. What is your response to these skeptics?
A. We understand that some people may have doubts about a technology capable of converting CO2 (a bad thing) into building materials (a good thing). However, Calera’s MAP technology works and we have proven it in our pilot plant, and at our demonstration plant. After reviewing our technology in depth under confidentiality agreements, many independent scientists, researchers and industry experts agree with our conclusion. Also, we have filed over 300 patents around the world with over 3,500 claims and now have numerous patents actually granted, demonstrating novelty. Over time, as more patents are granted and the details become public, the skeptics will learn more and more about what we actually do in our process.
Q. Your critics say that you would emit more CO2 than what you would capture because the feedstocks you use are energy intensive.
A. To supplement our CO2 capture chemistry in some locations, we will make our own alkalinity/CO2 capture feedstock through a new electrochemistry process, our ABLE (Alkalinity Based on Low Energy) technology. This is a dramatic improvement over the current chlor-alkali process, and our proprietary technology is capable of delivering a sodium hydroxide feedstock with only a third to a fifth of the energy traditionally used in a chlor-alkali process. Patents have already been granted on this electrochemistry process.
Q. Cement is a hundred year old industry, how do you plan to replace it?
A. We do not plan to replace the cement industry but intend to work alongside it in developing products and markets that can continue to ensure its economic and environmental sustainability.
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