Closed loop calcination using heated carbon dioxide

Abstract

A manufacturing system 100 comprising; a carbon dioxide (CO2) source 106 to deliver a primary flow of CO2 114; a non-combustion heat source 108 that heats the primary CO2 flow; a reactor 102 having an

Description

BACKGROUND

[0001] Manufacturing processes, such as calcination processes are used to convert raw material into finished product using heat. One such process is used to convert raw materials into cement. These processes often generate carbon dioxide as part of the process. In addition, existing systems often used combustion as the source of heat to facilitate the process. Thus, these manufacturing processes can be a significant source of carbon dioxide emissions. SUMMARY

[0002] In one aspect, a manufacturing system includes a carbon dioxide source operable to deliver a primary flow of carbon dioxide, a non-combustion heat source that operates to heat the primary flow of carbon dioxide, and a reactor having an inlet end and an outlet end, the outlet end having a lower elevation than the inlet end and positioned to receive the primary flow of carbon dioxide from the non-combustion heat source. A flow of raw material enters the reactor at the inlet end and a flow of finished product exits the reactor at the outlet end, the reactor cooperating with the primary flow of carbon dioxide to convert the flow of raw material to the flow of finished product. An enclosure is arranged to capture carbon dioxide from the non-combustion heat source and the reactor, and to direct the capture carbon dioxide to the carbon dioxide source.

[0003] In another aspect, a manufacturing system includes a carbon dioxide source operable to deliver a primary flow of carbon dioxide, and a heat source that operates in response to a flow of electrical power to heat the primary flow of carbon dioxide. A plurality of pre-heaters is arranged in series with a first pre-heater of the plurality of pre-heaters receiving a flow of raw materials and a last pre-heater of the plurality of pre-heaters discharging the flow of raw material. A rotary kiln has an inlet end that receives the flow of raw material from the last pre heater and an outlet end that discharges finished product, the outlet end having a lower elevation than the inlet end. An enclosure is arranged to capture carbon dioxide from the heat source, the rotary kiln, and the plurality of pre-heaters. The enclosure contains the captured carbon dioxide as it mixes with the primary flow of carbon dioxide as the primary flow of carbon dioxide flows from the heat source where it is preheated, through the rotary kiln where the primary flow of carbon dioxide heats the flow of raw material, and through the plurality of pre-heaters. A return line is connected between the enclosure and the carbon dioxide source to direct the captured carbon dioxide and the primary flow of carbon dioxide to the carbon dioxide source.

[0004] In yet another aspect, a method of converting a raw material into a finished product includes delivering a flow of raw material to a first pre-heater in a plurality of pre-heaters, the plurality of pre-heaters arranged in series to define a last pre-heater in the plurality of preheaters. The method also includes discharging the flow of raw material from the last pre-heater and into an inlet end of a reactor, and operating the reactor to move the flow of raw material from the inlet end of the reactor to an outlet end. The method further includes storing a quantity of carbon dioxide in a carbon dioxide source, drawing a primary flow of carbon dioxide from the carbon dioxide source, heating the primary flow of carbon dioxide using an electrically-powered heater, and heating the flow of raw material by directing the heated primary flow of carbon dioxide into the outlet end of the reactor, through the reactor to the outlet end, into the last pre-heater, and through each of the plurality of pre-heaters. The method also includes enclosing the electrically powered heater, the reactor, and the plurality of pre-heaters to capture carbon dioxide that is released from the flow of raw material during the heating step and to contain the primary flow of carbon dioxide. The method also includes redirecting the captured carbon dioxide and the primary flow of carbon dioxide to the carbon dioxide source for reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0006] FIG. 1 is schematic illustration of a manufacturing system that includes a noncombustion heat source and an enclosure.

[0007] FIG. 2 is schematic illustration of a manufacturing system that includes a noncombustion heat source and an enclosure.

[0008] FIG. 3 illustrates a process to convert raw material into finished product. DETAILED DESCRIPTION

[0009] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in this description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0010] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout. The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0011] It should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms “including,” “having,” and “comprising,” as well as derivatives thereof, mean inclusion without limitation. The singular forms “a”, “an” and “the” are intended to include the plural forms (i.e., one or more) as well, unless the context clearly indicates otherwise. Further, the term “and / or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term “or” is inclusive, meaning and / or, unless the context clearly indicates otherwise. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. Furthermore, while multiple embodiments or constructions may be described herein, any features, methods, steps, components, etc. described with regard to one embodiment are equally applicable to other embodiments absent a specific statement to the contrary.

[0012] Also, terms such as “first”, “second”, “third” and so forth may be used herein to refer to various elements, information, functions, or acts, but should not be considered as limiting in any way. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0013] In addition, the term “adjacent to” may mean that an element is relatively near to but not in contact with a further element or that the element is in contact with the further portion unless the context clearly indicates otherwise. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms “about” or “substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard is available, a variation of twenty percent would fall within the meaning of these terms unless otherwise stated.

[0014] Calcination is a thermal treatment process that involves heating solid materials to high temperatures, typically between 700°C and 1200°C, in a controlled environment with limited oxygen supply. This process is primarily used to induce chemical changes in the material, such as the removal of volatile substances, moisture, or the thermal decomposition of compounds. A common use of the calcination process is the conversion of calcium carbonate (limestone) into calcium oxide (quicklime) and carbon dioxide gas during the manufacture of cement.

[0015] Calcination has several objectives including the goal of decomposing compounds, particularly carbonates, into their oxides. For example, the reaction for calcium carbonate is:

[0016] CaCO3(s)^CaO(s)+CO2(g).

[0017] The calcination process also helps in purifying materials by removing impurities and volatile components. In addition, calcination can lead to the oxidation of certain materials, facilitating further chemical reactions necessary for various industrial applications.

[0018] As is well known, calcination is widely used in various industries, including the conversion of limestone to lime for cement manufacturing, the extraction of metals from their ores, particularly when the ores are in the form of carbonates or sulfates, and in the processing of materials like bauxite (to produce alumina) and gypsum (to produce plaster) by removing water of crystallization. In addition, calcination could be used for the regeneration of quick lime from lime mud in the pulp and paper industry.

[0019] During cement production, an intermediary step of clinker production is often performed. A cement clinker is a crucial intermediary product in the production of Portland cement. It is formed by heating a mixture of limestone and aluminosilicate materials, such as clay, in a rotary kiln at high temperatures, typically between 1400°C and 1500°C. This process, known as sintering, results in the formation of small, hard nodules or lumps (clinkers) that range in size from approximately 3 mm to 25 mm in diameter.

[0020] For the specific application of forming Portland cement, the composition of the clinker typically falls within the following ranges: • Lime (CaO): 60% to 65% • Silica (S1O2): 17% to 25% • Alumina (AI2O3): 3% to 8% • Magnesia (MgO): 1% to 3% • Iron Oxide (Fe2Os): 0.5% to 6% • Calcium Sulfate (Gypsum): 0.1% to 0.5% • Sulfur Trioxide (SO3): 1% to 3%.

[0021] These components influence the properties of the resulting cement, such as its strength and setting time. Of course, other ranges are possible and will not affect the operation of the system described herein.

[0022] In foregoing compounds may further be found in the forms of Alite (CasSiOs) which is the primary mineral phase, contributing to the strength of the cement, Belite (Ca2SiO4) which is another calcium silicate that hydrates more slowly than alite, affecting the long-term strength, Tricalcium Aluminate (CasALOe) which contributes to the early strength of the cement but can lead to flash setting if not controlled, and Calcium Aluminoferrite (Ca2(Al,Fe)2Os) which plays a role in the color and setting properties of the cement.

[0023] The production of clinker involves the sintering of these minerals, which aggregate together without melting completely, forming nodules (or clinkers) typically between 3 mm and 25 mm in diameter. After cooling, each clinker is ground into a fine powder and mixed with gypsum to produce cement. The gypsum regulates the setting time and enhances the compressive strength of the cement. Due to its durability and ability to be stored for extended periods without quality loss, clinker is often traded internationally, particularly in regions where raw materials for cement are scarce. In summary, clinker is a fundamental material in cement production, serving as the backbone for various types of cement used in construction. Its composition and processing conditions directly affect the quality and characteristics of the final cement product.

[0024] To be clear, different processes may form different products entirely. The formation of clinkers and specifically clinkers for the formation of cement are one example for which the arrangements described herein are particularly suited. However, it should be clear that the arrangements described herein could be used for any calcination process or other similar thermal processes to form other products or intermediaries. As such the arrangements described herein should not be limited to the production of cement.

[0025] FIG. 1 schematically illustrates a manufacturing system 100 capable of treating a raw material to produce a desired finished product. In similar systems, heated air is used to heat the raw materials to produce the desired finished product. However, the heating process may produce significant quantities of carbon dioxide that are emitted into the atmosphere.

[0026] The manufacturing system 100 illustrated in FIG. 1 addresses this problem by using carbon dioxide as the heating fluid while also capturing any generated carbon dioxide. In the illustrated system, a carbon dioxide source 106, typically in the form of a tank or pressure vessel provides a flow of cold carbon dioxide 114 to a heat source, illustrated as a Turbo Heater 108 in FIG. 1. The Turbo Heater 108 operates to heat the cold carbon dioxide 114 and to output a flow of heated carbon dioxide 116. The Turbo Heater 108 could include a single Turbo Heater 108, a multi-stage Turbo Heater 108, or multiple parallel or series Turbo Heaters 108 as desired. In addition, other heat sources could be employed with the preferred heat sources being non-combustion based.

[0027] The heated carbon dioxide 116 then flows into a reactor 102. A flow of input raw materials 110 also enters the reactor 102. Within the reactor 102 heat is transferred from the heated carbon dioxide 116 to the input raw material 110 to facilitate a chemical or mechanical process that ultimately converts the input raw material 110 into an output finished product 112 and converts the heated carbon dioxide 116 into a flow of cool untreated carbon dioxide 118. In the illustrated construction, the reactor 102 has a counterflow arrangement such that an inlet end 126 includes the inlet for the input raw material 110 and the outlet of the flow of cool untreated carbon dioxide 118 with the opposite outlet end 128 including the outlet for the output finished product 112 and the inlet for the flow of heated carbon dioxide 116. Of course, other arrangements of the reactor 102 are possible. In addition, the reactor 102 may include one component or multiple separate components.

[0028] The cool untreated carbon dioxide 118 may flow to one or more auxiliary treatment devices 104 to treat the flow of cool untreated carbon dioxide 118 and to output a flow of cool treated carbon dioxide 120. The flow of cool treated carbon dioxide 120 is then returned to the carbon dioxide source 106 to complete the cycle. While any suitable auxiliary treatment device 104 may be employed, examples include waste heat recovery devices, dust or particle filters, moisture separators, and the like.

[0029] The flow of cool treated carbon dioxide 120 includes the carbon dioxide that made up the initial flow of cold carbon dioxide 114 as well as any carbon dioxide that may be produced, released or otherwise liberated in the Turbo Heater 108 and the reactor 102. While FIG. 1 illustrates an enclosure 124 that surrounds the Turbo Heater 108 and the reactor 102, most arrangements include airtight housings around the Turbo Heater 108 and the reactor 102 that inhibit leakage of the cold carbon dioxide 114 and the output finished product 112 as well as capture any produced or released carbon dioxide. Thus, the mass of carbon dioxide in the flow of cool untreated carbon dioxide 118 is greater than the mass of carbon dioxide in the flow of cold carbon dioxide 114. As such, the quantity of carbon dioxide retuned to the carbon dioxide source 106 in the flow of cool treated carbon dioxide 120 is greater than the quantity of carbon dioxide extracted as the flow of cold carbon dioxide 114. To maintain the desired quantity of carbon dioxide in the carbon dioxide source 106, an extraction flow 122 is provided. Carbon dioxide may be removed periodically or continuously as desired to maintain the mass and pressure desired in the carbon dioxide source 106.

[0030] In one example, the reactor 102 is a calciner that operates to treat limestone (CaCOs) and convert that limestone to lime (CaO) as part of a cement manufacturing process. In order to perform this operation, the flow of cold carbon dioxide 114 may be maintained at about 300 degrees Celsius with the Turbo Heater 108 operating to heat the carbon dioxide and discharge the flow of heated carbon dioxide 116 at a temperature between about 800 Celsius and 900 Celsius. Of course, different temperature ranges could be used for this process or other processes as may be necessary.

[0031] FIG. 2 schematically illustrates, in more detail, a process schematic of a manufacturing process such as a calcination process suitable for use in converting raw materials into finished products. The manufacture of cement is an example of a calcination process in which raw materials can be converted to “clinkers” using the arrangement illustrated in FIG. 2. While FIG. 2 will be described as a cement manufacturing process, one of ordinary skill in the art will realize that the illustrated arrangement, or similar arrangements could be used in the production of other finished products using other raw materials.

[0032] The manufacturing system 200 of FIG. 2 includes a carbon dioxide source 202, a heat source 208 such as a reactor or calciner, a plurality of pre-heaters 212, and an enclosure 218. The reactor illustrated herein includes a rotary kiln 210. However, the reactor could include rotary kilns, other calciners such as flash calciners, and / or other similar components or combinations thereof.

[0033] The carbon dioxide source 202 may include a tank or other storage device that is capable of holding sufficient carbon dioxide for the manufacturing system 200 plus any carbon dioxide that may be generated by the manufacturing system 200 during operation. In systems that collect the generated carbon dioxide some means of removing excess carbon dioxide is generally required to maintain the mass balance within the system. In some arrangements, the carbon dioxide source 202 may include a carbon dioxide extraction 232 that allows for the removal of carbon dioxide from the carbon dioxide source 202.

[0034] The heat source 208 is preferably a non-combustion heat source such as an electrically powered heat source 208. Non-combustion heat sources 208 are preferred because they do not generate additional carbon dioxide locally within the manufacturing system 200 such that the system is capable of capturing generated carbon dioxide from the manufacturing system 200 without being overwhelmed by the emissions of a combustion source. Of course, if a combustion-based heat source 208 is employed, the manufacturing system 200 may be arranged to capture that additional carbon dioxide. Examples of suitable non-combustion heat sources 208 include Turbo Heaters that heat a flow of gas or large electric heaters and in particular megawatt scale induction heaters that can be used to heat a flow of fluid. A source of electricity is provided to deliver the necessary electrical power 206 to the heat source 208.

[0035] The rotary kiln 210 is a cylindrical component that is slightly declined from the horizontal between an inlet end 236 and an outlet end 238 and rotates slowly around its longitudinal axis. The rotary kiln 210 is typically made of steel and can be quite large, often measuring up to 230 meters in length and 6 meters in diameter. Many rotary kilns 210 include a refractory liner which can include bricks or cast refractory concrete, designed to withstand the high temperatures inside the kiln.

[0036] As is known in the art, rotary kilns 210 are specialized pyroprocessing devices primarily used to heat materials to high temperatures for various industrial processes, including calcination and sintering. It operates continuously and is designed to facilitate chemical reactions or physical changes in solid materials through high-temperature treatment.

[0037] The plurality of pre-heaters 212 are positioned such that each of the pre-heaters of the plurality of pre-heaters 212 are arranged in series such that a first pre-heater 214 receives a flow of raw material 226 into the manufacturing system 200 and directs that flow of raw material 226 to a second pre-heater which in turn directs the 226 to an nth pre-heater, until a last pre-heater 216 is reached. The flow of raw material 226 is then directed to the rotary kiln 210 as will be discussed in greater detail.

[0038] In the illustrated construction, the plurality of pre-heaters 212 consists of multiple cyclone pre-reactors arranged in stages, usually between four to six, with ducts connecting adjacent reactors. The cyclone pre-reactors are set up in series and vertically, which allows for efficient heat exchange and separation of materials. Each pre-heater includes a cyclone preheater that facilitates gas-solid mixing, heat exchange, and separation. In addition, the plurality of pre-heaters 212 may include a combination of tall, thin cyclone pre-heaters at the top for better gas-solid separation and shorter, wider cyclones lower down to reduce pressure loss. A common configuration is a five-stage preheater as illustrated in FIG. 2. It should be noted that while a plurality of pre-heaters 212 is illustrated in FIG. 2 and described. Other arrangements could include a single pre-heater and could include pre-heaters other than cyclone pre-heaters as well as a combination of cyclone and non-cyclone pre-heaters.

[0039] The enclosure includes one or more structures that surround and enclose the various components of the manufacturing system 200 and in particular enclose those components that may generate or liberate carbon dioxide to facilitate the collection or capture of that carbon dioxide. In particular, the enclosure surrounds the heat source 208, the rotary kiln 210, and the plurality of pre-heaters 212 and provides a substantially air-tight seal. In addition, the components themselves could be airtight such that they serve as the enclosure.

[0040] During operation of the manufacturing system 200, there are two distinct material flows. The two materials can flow in the same direction, or as illustrated in FIG. 2, can flow in opposite directions.

[0041] The first material flow includes a flow of raw material 226 that enters the manufacturing system 200 at the plurality of pre-heaters 212 and specifically at the first preheater 214. The flow of raw material 226 then proceeds through each of the pre-heaters of the plurality of pre-heaters 212 in sequence until it reaches the last pre-heater 216. From the last pre-heater 216, the flow of raw material 226 is discharged into the inlet end 236 of the rotary kiln 210. As the rotary kiln 210 rotates, the flow of raw material 226 moves downward toward the outlet end 238 of the rotary kiln 210. As the flow of raw material 226 moves along the rotary kiln 210 it is transformed of converted to a finished product 228 which is what is ultimately discharged from the outlet end 238 of the rotary kiln 210.\

[0042] The second material flow includes a continuous and cyclical flow of carbon dioxide that generally moves in the opposite direction as the flow of raw material 226. Of course, other operations may employ a batch process in which carbon dioxide is added periodically.

[0043] The manufacturing system 200 is designed to operate with a carbon dioxide atmosphere within the enclosure 218 rather than atypical air-filled arrangement. Thus, during operation, a primary flow of carbon dioxide 204 passes from the carbon dioxide source 202 to the heat source 208 within the enclosure 218. The primary flow of carbon dioxide 204 may be pressurized before entering the enclosure 218 or, such as with a Turbo Heater, the primary flow of carbon dioxide 204 may be pressurized by the heat source 208.

[0044] After heating, the primary flow of carbon dioxide 204 passes into the rotary kiln 210 via the outlet end 238 when the carbon dioxide is at its highest temperature. The primary flow of carbon dioxide 204 flows upward along the rotary kiln 210 and operates to convert or react with the flow of raw material 226 to produce the finished product 228 and, during that process to produce or liberate additional carbon dioxide within the rotary kiln 210. The primary flow of carbon dioxide 204 and the produced or liberated carbon dioxide (kiln-produced carbon dioxide) mix within the rotary kiln 210 and are ultimately discharged from the rotary kiln 210 at the inlet end 236. While the discharged primary flow of carbon dioxide 204 and kiln-produced carbon dioxide mixture is cooled in the rotary kiln 210, the mixture is still sufficiently hot to be useful for pre-heating the flow of raw material 226 in the plurality of preheaters 212.

[0045] The mixture of the primary flow of carbon dioxide 204 and kiln-produced carbon dioxide enters the last pre-heater 216 first and then flows through the series of pre-heaters in reverse order until it is discharged from the first pre-heater 214. As the mixture of the primary flow of carbon dioxide 204 and kiln-produced carbon dioxide flows through the plurality of pre-heaters 212 its temperature drops while the temperature of the 226 is increased. During this process, additional carbon dioxide may be liberated or produced, and that carbon dioxide may flow with the primary flow of carbon dioxide 204 or may escape into the interior of the enclosure 218.

[0046] Thus, the rotary kiln 210 and plurality of pre-heaters 212 cooperate to define a counter flow heat exchanger with the flow of raw material 226 operating as the cold fluid and the primary flow of carbon dioxide 204 as well as any liberated or produced carbon dioxide operating as the hot fluid.

[0047] After exiting the first pre-heater 214, the primary flow of carbon dioxide 204 as well as any liberated or produced carbon dioxide is captured within the enclosure 218. A return line 240 transports the now used and captured carbon dioxide back to the carbon dioxide source 202 for re-use in the cycle. If the carbon dioxide exceeds the desired capacity of the carbon dioxide source 202, excess carbon dioxide can be extracted via the carbon dioxide extraction 232 and used in another process or otherwise sequestered.

[0048] In other constructions, additional components may be added to enhance the efficiency or other aspects of the process or to facilitate a different process. For example, a secondary flow of carbon dioxide 234 may be extracted from the carbon dioxide source 202 and mixed with the mixer 220 to provide an accurately controlled temperature for the carbon dioxide at the outlet end 238 of the rotary kiln 210.

[0049] Another arrangement may include a kiln mixer 222 disposed near the inlet end 236 of the rotary kiln 210. A bypass flow path 224 is provided to direct a portion of the heated primary flow of carbon dioxide 204 to the kiln mixer 222 such that the portion of the primary flow of carbon dioxide 204 bypasses the rotary kiln 210 and remains significantly hotter than the remainder of the primary flow of carbon dioxide 204 that passes through the rotary kiln 210. The two portions of the primary flow of carbon dioxide 204 are remixed using the kiln mixer 222 to provide a primary flow of carbon dioxide 204 to the plurality of pre-heaters 212 that is hotter than it would have been had it all passed through the rotary kiln 210.

[0050] In still another arrangement, a dust filter 230 is positioned in the return line 240 to remove unwanted dust or debris prior to returning the captured carbon dioxide from the enclosure 218 to the carbon dioxide source 202. Other components such as auxiliary gas treatment and dewatering or moisture separators could also be employed as required.

[0051] In a delivering raw material step 302, a process to convert raw material into finished product 300 delivers a flow of raw material 226 to a first pre-heater 214 in a plurality of pre heaters 212, the plurality of pre-heaters 212 arranged in series to define a last pre-heater 216 in the plurality of pre-heaters 212.

[0052] The flow of raw material 226 from the last pre-heater 216 is directed into an inlet end 236 of a rotary kiln 210 in a discharging raw material step 304.

[0053] The rotary kiln 210 is then operated in an operating the rotary kiln step 306. Operation of the rotary kiln 210 continues the process to convert raw material into finished product 300 and moves the flow of raw material 226 from the inlet end 236 of the rotary kiln 210 to an outlet end 238.

[0054] In a storing carbon dioxide step 308, the process to convert raw material into finished product 300 stores a quantity of carbon dioxide in a carbon dioxide source 202.

[0055] The process to convert raw material into finished product 300 draws a primary flow of carbon dioxide 204 from the carbon dioxide source 202 in a drawing a flow of carbon dioxide step 310.

[0056] In a heating the flow of carbon dioxide step 312, the process to convert raw material into finished product 300 heats the primary flow of carbon dioxide 204 using an electrically powered heat source 208.

[0057] In a heating the raw material step 314, the process to convert raw material into finished product 300 heats the flow of raw material 226 by directing the heated primary flow of carbon dioxide 204 into the outlet end 238 of the rotary kiln 210, through the rotary kiln 210 to the outlet end 238, into the last pre-heater 216, and through each of the plurality of pre-heaters 212.

[0058] The process to convert raw material into finished product 300 further includes enclosing the electrically powered reactor heat source 208, the rotary kiln 210, and the plurality of pre-heaters 212 to capture carbon dioxide that is released from the flow of raw material 226 during the heating the flow of carbon dioxide step 312 and to contain the primary flow of carbon dioxide 204 in an enclosure step 316.

[0059] In a redirecting the carbon dioxide step 318, the process to convert raw material into finished product 300 redirects the captured carbon dioxide and the primary flow of carbon dioxide 204 to the carbon dioxide source 202 for reuse.

[0060] The arrangement disclosed herein uses carbon dioxide in place of air throughout the process to facilitate the capture and reuse of the carbon dioxide. By using a non-combustion heat source, no other gases beyond those produced during the process enter into the system. While the arrangement illustrated could be used with a combustion heat source, that would introduce additional gasses and would make it more difficult to separate the carbon dioxide. Thus, the use of non-combustion heat sources is preferred. By utilizing the process and arrangement described herein the manufacturing system 200 can perform a calcination process or another process to convert a raw material into a finished product with zero or near zero carbon dioxide emissions. In addition, by enclosing the sources of carbon dioxide and by using carbon dioxide as the heat transfer fluid, the additional carbon dioxide naturally produced by the calcination reaction is not further diluted (as is the case when the heat is provided in a flow of air) and can more efficiently be captured without emission to the atmosphere.

[0061] In addition, the arrangement illustrated could be used for a process that includes the introduction of a diluent such as steam which will improve the chemical kinetics of the system and may be separated from the carbon dioxide at the dust filter 230 or another component positioned near the dust filter 230 that may be more suited to the task of moisture removal and separation.

[0062] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

[0063] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

Claims

What is claimed is:

1. A manufacturing system comprising:a carbon dioxide source operable to deliver a primary flow of carbon dioxide;a non-combustion heat source that operates to heat the primary flow of carbon dioxide;a reactor having an inlet end and an outlet end, the outlet end positioned to receive the primary flow of carbon dioxide from the non-combustion heat source;a flow of raw material entering the reactor at the inlet end;a flow of finished product exiting the reactor at the outlet end, the reactor cooperating with the primary flow of carbon dioxide to convert the flow of raw material to the flow of finished product; andan enclosure arranged to capture carbon dioxide from the non-combustion heat source and the reactor, and direct the captured carbon dioxide to the carbon dioxide source.

2. The manufacturing system of claim 1, further comprising a pre-heater positioned to receive the flow of raw material and the primary flow of carbon dioxide, the primary flow of carbon dioxide being received from the inlet end of the reactor, and wherein the enclosure is arranged to capture carbon dioxide from the pre-heater and to and direct the captured carbon dioxide to the carbon dioxide source.

3. The manufacturing system of claim 1, further comprising a mixer positioned to receive the primary flow of carbon dioxide and a secondary flow of carbon dioxide, the mixer operable to mix the primary flow of carbon dioxide and the secondary flow of carbon dioxide to the outlet end of the reactor.

4. The manufacturing system of claim 1, wherein the pre-heater is one of a plurality of pre-heaters arranged in series.

5. The manufacturing system of claim 1, wherein the non-combustion heat source includes an electrical induction heater.

6. The manufacturing system of claim 1, wherein the non-combustion heat source includes a Turbo Heater.

7. The manufacturing system of claim 1, wherein the reactor includes a rotary kiln, and wherein the outlet end has a lower elevation than the inlet end.

8. The manufacturing system of claim 7, further comprising a finished product discharged from an outlet end of the rotary kiln, the finished product including at least one of alite, belite, tricalcium aluminate, and calcium aluminoferrite.

9. The manufacturing system of claim 1, further comprising a kiln mixer positioned to receive the primary flow of carbon dioxide from the inlet end of the heater; and a bypass flow path formed between the non-combustion heat source and the kiln mixer to direct a portion of the heated primary flow of carbon dioxide to the kiln mixer to reheat the primary flow of carbon dioxide before entry into the pre-heater.

10. The manufacturing system of claim 1, wherein the pre-heater is a cyclone preheater.

11. A manufacturing system comprising:a carbon dioxide source operable to deliver a primary flow of carbon dioxide;a heat source that operates in response to a flow of electrical power to heat the primary flow of carbon dioxide;a plurality of pre-heaters arranged in series with a first pre-heater of the plurality of preheaters receiving a flow of raw materials and a last pre-heater of the plurality of pre-heaters discharging the flow of raw material;a rotary kiln having an inlet end that receives the flow of raw material from the last preheater and an outlet end that discharges finished product, the outlet end having a lower elevation than the inlet end;an enclosure arranged to capture carbon dioxide from the heat source, the rotary kiln, and the plurality of pre-heaters, the enclosure containing the captured carbon dioxide as it mixes with the primary flow of carbon dioxide as the primary flow of carbon dioxide flows from the heat source where it is preheated, through the rotary kiln where the primary flow of carbon dioxide heats the flow of raw material, and through the plurality of pre-heaters; anda return line connected between the enclosure and the carbon dioxide source to direct the captured carbon dioxide and the primary flow of carbon dioxide to the carbon dioxide source.

12. The manufacturing system of claim 11, further comprising a mixer positioned to receive the primary flow of carbon dioxide and a secondary flow of carbon dioxide, the mixer operable to mix the primary flow of carbon dioxide and the secondary flow of carbon dioxide to the outlet end of the rotary kiln.

13. The manufacturing system of claim 11, wherein the non-combustion heat source includes an electrical induction heater.

14. The manufacturing system of claim 11, wherein the non-combustion heat source includes a Turbo Heater.

15. The manufacturing system of claim 11, wherein the flow of raw material includes a flow of at least one of limestone, clay, shale, and gypsum.

16. The manufacturing system of claim 15, wherein the finished product includes at least one of alite, belite, tricalcium aluminate, and calcium aluminoferrite.

17. The manufacturing system of claim 11, further comprising a kiln mixer positioned to receive the primary flow of carbon dioxide from the inlet end of the rotary kiln; and a bypass flow path formed between the non-combustion heat source and the kiln mixer to direct a portion of the heated primary flow of carbon dioxide to the kiln mixer to reheat the primary flow of carbon dioxide before entry into the pre-heater.

18. The manufacturing system of claim 11, wherein each pre-heater of the plurality of pre-heaters is a cyclone pre-heater.

19. A method of converting a raw material into a finished product, the method comprising:delivering a flow of raw material to a first pre-heater in a plurality of pre-heaters, the plurality of pre-heaters arranged in series to define a last pre-heater in the plurality of preheaters;discharging the flow of raw material from the last pre-heater and into an inlet end of a reactor;operating the heater to move the flow of raw material from the inlet end of the reactor to an outlet end;storing a quantity of carbon dioxide in a carbon dioxide source;drawing a primary flow of carbon dioxide from the carbon dioxide source;heating the primary flow of carbon dioxide using an electrically powered reactor;heating the flow of raw material by directing the heated primary flow of carbon dioxide into the outlet end of the heater, through the heater to the outlet end, into the last pre-heater, and through each of the plurality of pre-heaters; andenclosing the electrically powered reactor, the heater, and the plurality of pre-heaters to capture carbon dioxide that is released from the flow of raw material during the heating step and to contain the primary flow of carbon dioxide; andredirecting the captured carbon dioxide and the primary flow of carbon dioxide to the carbon dioxide source for reuse.

20. The method of claim 19, further comprising directing a secondary flow of carbon dioxide from the carbon dioxide source to a mixer, and operating the mixer to mix the heated primary flow of carbon dioxide with the unheated secondary flow of carbon dioxide prior to directing the heated primary flow of carbon dioxide into the outlet end of the reactor.

21. The method of claim 19, further comprising directing a portion of the heated primary flow of carbon dioxide to a kiln mixer, the kiln mixer receiving the heated primary flow of carbon dioxide after it passes through the heater; and operating the mixer to heat the primary flow of carbon dioxide with the portion of the heated primary flow of carbon dioxide.

22. The method of claim 19, wherein the reactor includes a rotary kiln.s

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