Electro-activation system and method of electro-activating and providing auxiliary cementitious materials

Abstract

The present invention provides an activation system (1, 101, 201) and method of activating a solid auxiliary cementitious material (SCM) precursor. The activation system (1, 101, 201) comprises a first subsystem (2, 102, 202) comprising an inlet (21, 121), an electrical heating device (23, 123, 223), an activation vessel (22, 122), a fluid outlet (26, 126, 226), and a separation device (24, 124) configured to separate an activated solid SCM material from a fluid. The first subsystem (2, 102, 202) further comprises means for providing the activated solid SCM material to the second subsystem (3, 103, 203). The second subsystem (3, 103, 203) comprises a cooling device (31a, 31b, 31c, 131a, 131b, 131c).

Description

Background Art

[0001] In the cement industry, the use of supplementary cementitious materials (SCM) is strongly driven by the possibility of reducing CO2 emissions. SCM, such as fly ash or calcined clay, is a material that contributes to the properties of hardened concrete by hydraulic or pozzolanic activity when added in limited amounts. SCM can therefore replace some cement clinkers. Since clinker production is a large source of CO2 emissions, the use of SCM can contribute to the overall reduced CO2 emissions. Some SCMs need to be activated before obtaining cement properties. Clay needs to be calcined (dehydroxylated) to obtain cement properties. The calcination of clay occurs at a temperature lower than the formation temperature required for cement clinker, therefore requiring less energy.

[0002] The clay calcining process has evolved over time from a rotary kiln process known as "soak-calcining," where clay lumps are fed into a rotary kiln and calcined for about 20-30 minutes, to a flash calcining process, a much faster process that provides higher clay activity and lower operating costs.

[0003] One challenge in using calcined clay is the red coloration of the clay when it is exposed to high temperatures in the presence of oxygen. This is usually due to the presence of iron compounds in the clay, which are oxidized to iron oxide in the presence of oxygen. When the activated clay is mixed with cement clinker to produce cement, the red color is undesirable for most customers because the market requires grey cement rather than red cement.

[0004] There are several different techniques to avoid the reddish coloration of clays. In EP 3 218 320 B1, the clay is heated to an activation temperature of 600 to 1050° C. under reducing conditions to avoid oxidation of the iron, and then the clay is cooled under reducing conditions.

[0005] In US8906155 BB, clay may be calcined under oxidizing conditions and then the clay is heat treated under reducing conditions. Subsequently, the reduced clay is cooled in a first step under reducing conditions to obtain a stable reduced clay compound and then further cooled.

[0006] Reducing conditions are typically obtained by displacing oxygen with combustion exhaust gases or by adding a carbon source, optionally in combination with the addition of water.

[0007] In WO2021 / 224055, clay is calcined under oxidizing conditions and then the clay is heat treated under reducing conditions. Subsequently, the reduced clay is rapidly cooled under oxidizing conditions to preserve the stable reduced clay compound while enabling heat recovery to be maximized and even further reduce fuel consumption and CO2 footprint.

[0008] With the increasing discussion about CO2 emissions and the possible increase in the price of CO2 quotas, it is desirable to make the production of SCM, especially calcined clay, even more environmentally friendly and reduce CO2 emissions. In addition, it is desirable to improve the temperature control of the calcination system, because the calcination temperature has a large impact on the cement properties obtained from the calcined SCM. If the SCM is optimally activated (calcined), it achieves better cement properties and can therefore replace larger amounts of clinker. This results in the production of cement / concrete mixes produced with lower CO2 emissions. Summary of the invention

[0009] Therefore, in this context, the object of the present invention is to provide an alternative process for activating SCMs, by which some of the disadvantages of the prior art can be alleviated. In a first aspect of the present invention, these and further objects are obtained by an activation system for activating solid SCM-precursor materials into activated secondary cementitious materials (SCMs) suitable for clinker replacement. The activation system comprises a first subsystem and a second subsystem, the first subsystem comprising:

[0010] an inlet for providing a solid SCM-precursor material and optionally a reducing agent;

[0011] an electric heating device adapted to heat the fluid at least to an activation temperature of the solid material;

[0012] an activation vessel for contacting the solid SCM precursor material with the heating fluid to activate the solid SCM precursor material;

[0013] a fluid outlet configured to at least partially remove volatiles released from the activated solid SCM;

[0014] a separation device configured to substantially separate the activated solid SCM from the fluid;

[0015] means for providing the separated solid material to a second subsystem; and

[0016] wherein components in the first subsystem are arranged such that at least a portion of the fluid in the first subsystem is recirculated within the first subsystem;

[0017] The second subsystem includes:

[0018] A cooling device is configured to receive the separated activated solid material and cool the activated solid material to a stable temperature or below the stable temperature.

[0019] The activation system allows activation and optional calcination of SCM with low CO2 emissions. If the electricity used for heating is generated in a green way, the activation system allows for a substantially to completely fossil-free production of bioremediation SCM. Electric heating allows for greater temperature control in the system, which provides optimal conditions for activating SCM precursors.

[0020] The electric heating device does not require an oxygen source for combustion, and the composition of the fluid within the first subsystem can be easily adjusted and controlled to improve process conditions. Because the first subsystem is arranged with recirculation, the requirements for introducing fluid into the first subsystem can be limited. Therefore, the volume of the outlet fluid containing volatiles is small compared to a process with a constant supply of, for example, air.

[0021] The term "fluid" is used to describe the gas and / or liquid in the activation system, because the fluid can undergo phase changes due to heating and cooling operations. Once heated to the activation temperature, the fluid is generally in gaseous form, and if cooled to the condensation temperature, the fluid can at least partially liquefy. The fluid can include solids, such as fine particles. If additional fluid is provided to the activation system, it can be provided as a liquid or as a gas.

[0022] In one embodiment, the first subsystem may be operated under oxygen-depleted conditions or reducing conditions, which provide ideal conditions for providing a reduced SCM (eg, a gray clay material).

[0023] In one embodiment, the oxygen concentration in the first subsystem may be configured to oxidize the gaseous species released from the activated SCM into oxides. As an example, the oxygen concentration in the first subsystem may be configured to oxidize sulfur species into SO2.

[0024] The oxygen concentration in the first subsystem may be controlled by providing an oxygen source such as air, nitrogen-depleted oxygen-containing gas, or concentrated oxygen.

[0025] The activation vessel may be configured to provide a heat induced reaction. As an example, the activation vessel may be a calcination vessel, wherein the SCM precursor is calcined. Calcination generally refers to decomposition (of carbonates) and associated loss of gaseous species.

[0026] Depending on the mode of operation of the activation system, the main fluid added to the first subsystem may be volatiles released from the SCM precursor material as it is heated and activated. The type of volatiles is highly dependent on the environment in the first subsystem, such as oxidation / reduction conditions, but may include HO, NO x 、NH3、HCN、SO x , H2S, CO x and / or C x H y .

[0027] In the case where the feedstock contains organic carbon content, some oxygen can be provided to the first subsystem to promote combustion of the organic carbon and utilize energy and reduce emissions.

[0028] It is expected that some small amount of false air may enter the first subsystem and may be sufficient to burn organic carbon released from the feedstock.

[0029] Because SCM precursor materials typically release volatiles, some fluid must be removed from the first subsystem to maintain a substantially constant fluid balance.

[0030] In one or more embodiments, at least 50 V / V% of the fluid in the first subsystem is recirculated, such as at least 60 V / V%, such as 70 V / V%, such as 80 V / V%, such as 90 V / V%. In one or more embodiments, 60 V / V% to 95 V / V% of the fluid in the first subsystem is recirculated. Depending on the activation temperature and the heat loss in the system, it may be necessary to further cool the fluid in the first system. This may be due to condensation or because a lower temperature is required for a pressurized container (e.g., a fan).

[0031] In one or more embodiments, the first subsystem may include multiple components to manipulate the temperature of the fluid through a cycle of heating and cooling steps.

[0032] Due to the cooling and heating in the activation system, the term "fluid" is used to describe both gases and liquids, as these may undergo condensation and evaporation through the system.

[0033] In some embodiments of the invention, it may be desirable to provide some addition of a reducing agent. The reducing agent may be hydrogen, ammonia and / or a small amount of a carbon compound. This depends on which substances are released from the SCM-precursor and which process conditions are preferred in the activation system.

[0034] In one or more embodiments, the cooling device includes a cooling gas inlet and a cooling container, and the cooling container is configured to contact the activated solid SCM provided from the first subsystem with the cooling gas provided from the cooling gas inlet, so that the activated SCM is cooled from the general activation temperature to the stable temperature. Preferably, the second subsystem is substantially isolated from the first subsystem fluid. This means that substantially no fluid from the first subsystem is provided to the second subsystem together with the separated solid. It should be understood that it may be impossible to separate all fluids from the solid, and "substantially no fluid" should be understood as how a technician will interpret "no fluid" with the technical tolerance provided by the separation method of the prior art.

[0035] In one or more embodiments, the activation system includes a reduction vessel connected to the first subsystem. The reduction vessel can be configured to receive the activated SCM material, provide a residence time of the activated SCM material under reducing conditions to provide a reduced SCM. The reduction vessel can be further connected to a cooling vessel.

[0036] Solid SCM precursor material means a solid material that achieves cementitious properties once activated and can therefore be used as an SCM. Possible examples of SCM precursors that require calcination / activation include, but are not limited to, shale, clay, pozzolan (partially hydrated), zeolite, partially hydrated ash (e.g., deposited fly ash).

[0037] The difference between the first subsystem and the second subsystem is that the temperature range of operation is different. The first subsystem can be characterized as a high temperature system, and the second subsystem can be characterized as a low temperature system. The temperature in the first subsystem can be from the general condensation temperature of the volatiles to at least higher than the activation temperature of the SCM precursor. The activation temperature depends on the chemical composition of the SCM precursor. In particular, different clays may require different activation temperatures. The activation temperature can vary between about 600°C and 1100°C. The activation system is generally optimized for a specific type of SCM with slight chemical differences. As an example, the activation system can be optimized for a temperature of 600°C to 700°C, 700°C to 800°C, 800°C to 900°C, 900°C to 1000°C, or 1000°C to 1100°C.

[0038] The electric heating device may be an arc burner, an electric heating gas generator, an induction heating device and / or a resistance heating device.

[0039] The activated SCM may be a calcined SCM, ie a SCM-precursor which has been thermally activated to achieve / improve its cementitious properties. Thermally activated clays are often referred to as calcined clays.

[0040] Examples of gas-solid separation devices may include, but are not limited to, gas cyclones and / or filters.

[0041] The fluid outlet may be a drain port to remove fluid from the system. In one embodiment, the fluid outlet is a vent / chimney where excess gas can be removed from the system. Alternatively, the fluid outlet may be a liquid outlet arranged after the condenser so that volatiles are condensed and removed in liquid form. The fluid removed through the fluid outlet may be a mixture of volatiles and other components to maintain a constant flow in the system.

[0042] The fluid outlet may be connected to a suitable cleanup device for removing undesirable substances. In one or more embodiments, the cleaned fluid may be returned to the activation system.

[0043] The cooling gas inlet may provide cooling gas to the second subsystem. The cooling gas may be atmospheric air.

[0044] In one or more embodiments, the one or more cooling vessels may be heat exchangers, such as powder cooling. In a particular embodiment, the cooling vessel may be a gas cyclone, preferably a multi-stage gas cyclone.

[0045] In one or more embodiments of the present invention, at least 50 w / w% of the fluid in the first subsystem is recycled within the first subsystem, preferably 60 w / w%, more preferably 70 w / w%, more preferably 80 w / w%, more preferably 90 w / w%.

[0046] There are several potential benefits to recycling the volatile emissions released during preheating back to the calciner. Any released organic carbon emissions returned to the calciner can be burned, thereby reducing energy consumption and minimizing or even eliminating the need for organic emissions cleanup. Any potential NO x Can be reduced by simple low capital cleanup equipment such as SNCR rather than more expensive SCR. Any possible HCl, HF, SO2 emissions returned to the calciner can achieve higher adsorption efficiency to the solids in the calciner, minimizing the need for scrubber cleanup.

[0047] How much fluid is removed from the system through the fluid outlet and therefore how much fluid is recycled depends on the type and amount of volatiles generated by the SCM precursor and the gas tightness of the first subsystem.

[0048] In one or more embodiments of the present invention, the first subsystem further comprises a secondary heating device, so that heat can be provided in the mixed solution. The secondary heating device can be indirect heating. Indirect heating means that substantially no combustion gas or exhaust gas is provided to the first subsystem while heating with the secondary heating device. This can be achieved, for example, by heating outside the activation vessel with a hydrogen burner, or by heating the fluid in the first subsystem in a heat exchanger.

[0049] In one or more embodiments, the first subsystem further comprises a condenser unit, and wherein the fluid outlet is configured to remove condensate comprising at least a portion of the volatiles released from the activated SCM precursor.

[0050] In one or more embodiments, the first subsystem includes an O2 sensor and is configured with a device to adjust the O2 concentration based on a measurement from the O2 sensor. The O2 sensor may be a sensor that can measure a parameter indicative of O2 content.

[0051] O2 concentration can be regulated by removing the recirculating fluid of larger volume, or can be contacted with chemical recycling material.In some embodiments, it is desirable to remove dioxygen at least partially from fluid to obtain desired reaction during activation of SCM precursor.This can be achieved by contacting at least a portion of fluid with redox active solid, which is already in lower oxidation state before contact.Therefore, oxygen from fluid will react with redox active solid, causing oxidation state to increase, while removing dioxygen from fluid stream.The redox potential of redox active solid can be adjusted to adjust dioxygen concentration in fluid loop to desired redox potential.Activation or reactivation of redox active solid can be achieved by several methods, including contacting with other chemical substances or by electrochemical means.The example of redox active solid is metal oxide, such as FeO, CuO, MnO of different oxidation states.

[0052] In one or more embodiments, the components in the second subsystem are configured to recirculate at least a portion of the fluid in the second subsystem within the second subsystem.

[0053] The fluid (preferably gas) in the second subsystem can be used to cool the SCM from the first subsystem. This cooling step of the SCM can be performed once the SCM has left the first subsystem, and thus cooling can be performed in the second subsystem. This ensures that the oxygen-containing gas from the second subsystem is not provided to the first subsystem.

[0054] Preferably, the heat / energy obtained in the fluid is used for heat exchange with the first subsystem. In order to supply sufficient gas with a sufficiently low temperature, it may also be necessary to provide a constant flow of cooling gas (e.g. atmospheric air) to maintain a temperature suitable for cooling the SCM. In the case where the SCM is an iron-containing clay, the cooling should preferably be quenching, so that the temperature of the SCM is quickly reduced to below the stable temperature to maintain the grey color of the SCM.

[0055] In one or more embodiments, the reduction container is connected with the first subsystem and the second subsystem so that the SCM from the first subsystem passes through the reduction container before being provided to the second subsystem. In a specific embodiment, the excess reducing agent from the reduction container can be provided to the first subsystem. If the atmosphere in the first subsystem includes excessive oxygen concentration, a reduction container may be needed. In this case, the reduction container can be used to provide the SCM in a reduced state, thereby controlling the color of the iron-containing SCM. The reduction container is a container that allows SCM to pass through while comprising a reducing atmosphere (i.e., an atmosphere that is at least depleted of oxygen). This can be obtained by providing a reducing agent such as hydrogen, ammonia or a carbonaceous substance that exceeds the dioxygen available at a temperature higher than the ignition point of the reducing agent.

[0056] In one or more embodiments, the second subsystem includes a device for reducing the size of solid materials, a device for drying solid materials, and a gas-solid separation device. The device for reducing the size, drying and / or separating is located downstream of the cooler and is configured to receive hot gases from the cooler. The gas-solid separation device is configured to separate the dried solid material into a solid material flow. The second subsystem is further configured to provide the dry solid material flow to the first subsystem. In one or more embodiments, the size reduction device and the drying device can be a dryer crusher. In one or more embodiments, the gas-solid separation device can be an air filter or a gas cyclone. The above embodiments allow the use of hot gases from the cooler to dry the raw materials.

[0057] In one or more embodiments, the first subsystem includes a fluid inlet for providing water or steam to the first subsystem. It is believed that during activation, particularly of clay, some steam / humidity provides increased activity (cement properties). Steam can be provided as liquid water that evaporates upon entering the first subsystem, or can be provided using a steam generator.

[0058] In one or more embodiments, the second subsystem comprises an electric heating device. The electric heating device may be configured to heat the gas to a temperature suitable for drying the feedstock, preferably after cooling the activated SCM material.

[0059] In another aspect, the present invention relates to a method for activating a SCM precursor material to provide an activated SCM suitable for clinker replacement. The method comprises the following steps:

[0060] a. electrically heating the fluid to at least the activation temperature of the SCM precursor;

[0061] b. providing a solid SCM precursor and contacting the solid SCM precursor with an electrically heated fluid for a period of time sufficient to activate the SCM precursor into an SCM;

[0062] c. Separating the SCM from the fluid;

[0063] d. removing a portion of the fluid and recycling at least a portion of the remaining fluid to the electrical heating step;

[0064] e. Provide cooling gas;

[0065] f. Cooling the separated SCM to a temperature below the stable temperature of the SCM by contacting the activated SCM with the cooling gas.

[0066] Steps e. and f. are performed separately from steps a., b., c. and d. such that substantially no gas from steps e. and f. is provided to steps a., b., c. or d.

[0067] Separating the gases in different subsystems provides different process conditions at different stages of the process.

[0068] During activation of the SCM precursor, volatiles and water may be released. Therefore, a portion of the fluid is removed from the process to achieve a substantially constant fluid balance in the process.

[0069] In one or more embodiments, the fluid heated in step a. can be substantially oxygen-depleted. In this article, oxygen-depleted means a gas with an oxygen content less than that of atmospheric air. The fluid may include oxygen molecules bound in, for example, water, volatiles, or organic compounds, but in this case, oxygen-depleted refers to free oxygen molecules, i.e., dioxygen. Preferably, the oxygen content of the oxygen-depleted gas is less than 10 V / V%, more preferably less than 5 V / V%. In one or more embodiments, the oxygen-depleted gas is substantially free of oxygen gas.

[0070] The required activation temperature highly depends on the type of SCM. Typically, it is between 500°C-1100°C.

[0071] Depending on the SCM material, the stabilization temperature may be lower than 350-650° C. For iron-containing SCM materials that may oxidize to a reddish color, such as some clays, a stabilization temperature of 350-450° C. may be suitable to avoid a reddish coloration. For other SCM materials, a stabilization temperature of 450-650° C. may be suitable to substantially stop the chemical conversion of the SCM material.

[0072] In one or more embodiments, the CO2 concentration of the fluid recycled to the electric heating step may be measured. Preferably, the CO2 concentration may be adjusted. Depending on the desired operating conditions, it may be preferred to operate at a high or low CO2 concentration. In one or more embodiments, it may be desirable to operate at a concentration below 10 V / V%, such as below 5 V / V%.

[0073] In one or more embodiments, it may be desirable to operate at a CO2 concentration of 10 V / V% or higher, such as 20 V / V% or higher, such as 50 V / V% or higher.

[0074] The CO2 concentration can affect the reaction rates and equilibrium in the system. Additionally, it may be desirable to have an exhaust gas with a high CO2 concentration for carbon capture, or it may be desirable to have a low CO2 concentration if the outlet fluid is only exhausted to the surrounding environment.

[0075] In one or more embodiments, substantially all of the remaining gas in step d. is recycled after removing at least a portion of the materials released from the activated SCM solids.

[0076] In one or more embodiments, at least a portion of the gas is cooled and condensed into a condensate after step c., and wherein a portion of the fluid in step d. is removed in liquid form.

[0077] In one or more embodiments, the method further comprises the step of drying the solid SCM precursor using the cooling gas from step f. prior to step b., thereby recovering heat in the cooling gas. In one or more embodiments, the cooling gas used for drying can be partially or completely thermally boosted by electrically heating the cooling gas.

[0078] The dried SCM-precursor can be separated from the gas and fed to step a., without substantially providing any gas to step a..

[0079] In one or more embodiments, the method further comprises the step of removing heat from the cooling gas after step f. and recycling at least a portion of the cooled cooling gas to step f.

[0080] Other presently preferred embodiments and other advantages will be apparent from the following detailed description and the appended dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The invention will now be described in more detail by means of non-limiting examples of currently preferred embodiments and with reference to the accompanying drawings, in which:

[0082] Figure 1 A process flow chart of an activation system according to an embodiment of the present invention is shown;

[0083] Figure 2 A process flow chart of an activation system according to another embodiment of the present invention is shown;

[0084] Figure 3 A process flow chart of an activation system according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0085] Figure 1A process flow diagram of an activation system 1 according to one embodiment of the present invention is shown. The activation system 1 includes a first subsystem 2 and a second subsystem 3. An inlet 21 is configured to provide solid material to the first subsystem 2. In the specific embodiment shown, the inlet 21 is connected to an activation container 22. An example of an activation container may be a flash calciner or other heating device. Therefore, the solid material is directly provided to the activation container 22. The inlet 21 may optionally be configured to provide a reducing agent to the first subsystem 2. Optionally, a second inlet (not shown) may provide an optional reducing agent. In the activation container 22, the solid material is activated by contact with hot gas. An electric heating device 23 is provided upstream of the activation container 22 for heating the gas to at least the activation temperature of the solid material. A gas-solid separation device in the form of a gas cyclone 24 is provided downstream of the activation container 22. The separated solid material is provided to the second subsystem 3 through a feed pipe 25. The separated gas from the gas cyclone 24 is cooled in a heat exchanger and provided to a fan 28 before being circulated back to the electric heating device 23. The fluid outlet 26 is configured to remove a portion of the fluid from the first subsystem 2. Because different chemical compounds may be released from the solid material during activation, some fluid may be removed from the system to maintain a constant fluid balance in the first subsystem 2. The fluid outlet 26 may be adapted to remove outlet gas or outlet liquid depending on cooling in the heat exchanger 27.

[0086] The second subsystem comprises a cooling vessel in the form of a plurality of cyclones 31a, 31b, 31c. The activated solid material supplied to the second subsystem 3 via the feed pipe 25 is supplied to the cyclones 31a, 31b, 31c where it can be quenched with gas. In the embodiment shown, the cooling gas is atmospheric air supplied from the cooling gas inlet 32. A material outlet 34 is provided in the cyclone 31c to remove the cooled solid material. The cooling gas leaves through the gas outlet 33.

[0087] Now turn to Figure 2 , which shows a process flow diagram of an activation system 101 according to one or more embodiments of the present invention. The activation system 101 includes a first subsystem 102 and a second subsystem 103. The first subsystem 102 is similar to Figure 1 A first subsystem 2 is described.

[0088] The first subsystem 102 includes an inlet 121 connected to an activation vessel 122 and is configured to provide solid material into the first subsystem 102. The solid material is provided to the inlet 121 from a dryer 135, which utilizes gas from the second subsystem 103 to dry and depolymerize the solid material. This allows for better energy utilization and less evaporated water in the first subsystem 102. Optionally, the dryer 135 can be a grinding system for grinding and drying, such as a ball mill and a vertical roller mill. An electric heating device 123 is provided upstream of the activation vessel 122 for heating the gas to at least the activation temperature of the solid material. A gas-solid separation device in the form of a gas cyclone 124 is provided downstream of the activation vessel 122. The separated solid material is provided to the second subsystem 103 through a feed pipe 125. The reduction vessel 150 is in Figure 2 A second feed conduit 151 allows solid material from the gas cyclone 124 to be provided to the reduction vessel 150. If the reduction vessel operates with a combustible gas as the reducing agent, the reduction vessel may optionally be fluidly connected to the calciner to provide excess gas to the calciner for combustion.

[0089] The separated gas from the gas cyclone 124 can be optionally cooled in a heat exchanger 127 to remove and utilize the high temperature energy from the gas. The gas is then provided to a condenser 128, where the temperature is reduced to below the condensation point of the gas to remove the fluid and chemical compounds in liquid form released from the activated solid material. In the illustrated embodiment, the gas from the second subsystem 103 is used to condense the gas in the condenser 128. The heat recovered from the gas in the second subsystem 103 can then be used in a dryer 135 to dry the solid material. After condensation, the remaining fluid is returned to the electric heating device 123 and recycled within the first subsystem 102. One or more fluid outlets 126 can be configured to remove a portion of the condensed fluid and / or gas from the first subsystem 102.

[0090] exist Figure 2 In the illustrated embodiment, the second subsystem 103 is also provided in a loop configuration to provide a system that is as energy efficient as possible.

[0091] The second subsystem 103 includes a cooling vessel in the form of a plurality of cyclones 131a, 131b, 131c. The activated solid material is supplied to the second subsystem 103 via a feed pipe 125, or supplied to the cyclones 131a, 131b, 131c from a reduction vessel 150, where it is quenched with gas. In the illustrated embodiment, the cooling gas is a combination of atmospheric air and recirculated gas supplied from a cooling gas inlet 132. The solid material is supplied to the activation system 101 via a main inlet 137 and enters a dryer 135. The hot gas from the cyclones 131a, 131b, 131c is used to dry the solid material and convey the solid material to a filter 136. The gas and the solid are separated, and the solid is supplied to the first subsystem 102 for activation. The separated gas in the second subsystem is returned to the cyclone 131 or supplied to a condenser 128.

[0092] Now go to Figure 3 , which shows an activation system 201. The activation system 201 includes a first subsystem 202 and a second subsystem 203. The first subsystem 202 is similar to Figure 1 The first subsystem 2 is described. Subsystem 203 also includes a solid-gas separation device in the form of a thermal electrostatic precipitator (ESP) 251 or alternatively a ceramic filter. The thermal ESP 251 is located upstream of the fluid outlet 226 and the electric heating device 223 to remove particles before removing and reheating the fluid. Figure 3 The heat exchanger in FIG. 2 is shown as a multi-stage cyclone preheater 227. The fluid in the first subsystem 202 is not condensed, but the excess fluid is removed in gaseous form through the outlet 226.

[0093] The second subsystem 203 is configured with a gas-solid separation device in the form of a thermal ESP 264, a size reduction device in the form of a grinder 261, and an electric heating device in the form of an electric hot gas generator (HGG) 263. Alternatively, the grinder 261 can be a dry crusher. The second subsystem 202 is thus configured to heat and dry the raw materials using the heat from the cooling containers 231a, 231b, and 231c.

[0094] The hot gases from the cyclones 231a, 231b, 231c are provided to an optional hot ESP 264 to remove any solids. A portion of the gases may be provided directly to the grinder 261, while the remaining gases may be heated by the HGG 263. The feedstock inlet 237 is connected to the grinder, or just before the grinder, where the hot gases are used to dry the feedstock. Downstream of the grinder 261, the solid material may be filtered out in the filter device 265 and then provided to the material inlet 221 in the first subsystem 202.

[0095] The gas may be recycled and / or abated and purified within the second subsystem 203 .

Claims

1. An activation system (1, 101, 201) for activating a supplementary cementitious material (SCM) precursor into an SCM suitable for clinker replacement, the activation system (1, 101, 201) comprising a first subsystem (2, 102, 202) and a second subsystem (3, 103, 203), The first subsystem (2, 102, 202) includes: An inlet (21, 121) for providing a solid SCM precursor material and an optional reducing agent; an electric heating device (23, 123, 223) adapted to heat a fluid to at least the activation temperature of the solid SCM precursor material; an activation vessel (22, 122) for contacting the solid SCM precursor material with a heated fluid to activate the solid SCM precursor material; Fluid outlet (26, 126, 226); a separation device (24, 124) configured to separate the activated solid SCM material from the fluid; means for providing activated solid SCM material to a second subsystem (3, 103, 203); and wherein the components in the first subsystem (2, 102, 202) are arranged so that at least a portion of the fluid in the first subsystem (2, 102, 202) is recirculated within the first subsystem (2, 102, 202); The second subsystem (3, 103, 203) includes a cooling device (31a, 31b, 31c, 131a, 131b, 131c, 231a, 231b, 231c) configured to receive the separated activated solid SCM material and cool the activated solid SCM material to a stable temperature or below the stable temperature.

2. An activation system (1, 101, 201) according to claim 1, wherein at least 50V / V% of the fluid in the first subsystem (2, 102, 202) is recycled within the first subsystem (2, 102, 202), preferably 60V / V%, more preferably 70V / V%, more preferably 80V / V%, more preferably 90V / V%.

3. The activation system (1, 101, 201) according to claim 1 or 2, wherein: The first subsystem (2, 102, 202) further comprises a secondary heating device, preferably, wherein the secondary heating device is an indirect heating device.

4. The activation system (1, 101, 201) according to any one of the preceding claims, wherein: The first subsystem (2, 102, 202) further comprises a condenser unit (128), and wherein the fluid outlet (126) is configured to remove condensate containing substances released from the activated solid SCM material.

5. The activation system (1, 101, 201) according to any one of the preceding claims, wherein: The first subsystem (2, 102, 202) includes an O2 sensor and is provided with means for adjusting the O2 concentration based on measurements from the O2 sensor.

6. The activation system (1, 101, 201) according to any one of the preceding claims, wherein: At least a portion of the fluid in the second subsystem (3, 103, 203) is recirculated within the second subsystem (3, 103, 203).

7. The activation system (1, 101, 201) according to any one of the preceding claims, wherein: The second subsystem (3, 103, 203) comprises a device for reducing the size of solid materials, a device for drying solid materials and a gas-solid separation device, which is preferably located downstream of the cooling container and is configured to receive gas from the cooling container.

8. The activation system (1, 101, 201) according to claim 7, wherein: The dryer and sizer are located downstream of the cooling container and are configured to receive hot gas from the cooling container, and wherein the gas-solid separation device is configured to separate dry solid material into a solid material flow, and wherein the second subsystem (3, 103, 203) is also configured to provide the dry solid material flow to the first subsystem (2, 102, 202).

9. A system according to any one of the preceding claims, wherein: The first subsystem (2, 102, 202) comprises a fluid inlet for providing water or steam to the first subsystem (2, 102, 202).

10. A method of activating a solid SCM precursor material to provide an activated SCM suitable for clinker replacement, comprising the steps of: a. electrically heating the fluid to the activation temperature of the solid SCM precursor material; b. Providing a solid SCM precursor material and contacting the solid SCM precursor material with an electrically heated fluid; c. separating the activated SCM from the fluid; d. removing at least a portion of the fluid and recycling at least a portion of the remaining fluid to the electrical heating step; e. Provide cooling gas; f. Cooling the separated activated SCM to a temperature below the stable temperature of the SCM by contacting the activated SCM with the cooling gas.

11. A method according to claim 10, wherein steps a. to d. are performed in a first subsystem (2, 102, 202), and steps e. to f. are performed in a second subsystem (3, 103, 203), and wherein the first subsystem (2, 102, 202) and the second subsystem (3, 103, 203) are substantially fluidically isolated from each other.

12. A method according to claim 10 or 11, wherein the remaining fluid in step d. comprises at least 50 V / V%, such as at least 60 V / V%, such as 70 V / V%, such as 80 V / V%, such as 90 V / V% of the fluid provided in step a.

13. The method according to any one of claims 10 to 12, wherein after step c, the gas is cooled and condensed into a condensate, and wherein in step d the removal fluid is removed in liquid form.

14. A method according to any one of claims 10 to 13, wherein the method further comprises the step of drying the solid SCM precursor material using the cooling gas from step f. prior to step b.

15. The method according to any one of claims 10 to 14, wherein: The method further comprises the step of removing heat from the cooling gas after step f. and recycling at least a portion of the cooled cooling gas to step f.

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