Thermal coupling of cement production with gasification

Abstract

The present invention relates to a cement plant in which at least a portion of the hot air obtained from the clinker cooler is utilized to provide heat to at least one gasifier. At least a portion of the hot air is thermally coupled directly or indirectly with the at least one gasifier. The invention further relates to a method for gasifying a feedstock in at least one gasifier, wherein at least a portion of the hot air obtained from the clinker cooler is thermally coupled directly or indirectly with the at least one gasifier.

Description

TECHNICAL FIELD

[0001] The present invention relates to the thermal coupling of cement production in a cement plant and synthesis gas production in a synthesis gas plant comprising at least one gasifier. BACKGROUND

[0002] Cement production is one of the most energy-intensive industrial processes. Therefore, heat recovery and on-site utilization of the recovered heat is an important and necessary measure in cement production. In modern cement plants, raw clinker is preheated in a series of cyclone preheaters and fed to a cement kiln, most often a rotary kiln, where the raw clinker is heated to about 1350°C to 1500°C within a residence time of about 20 min to 40 min. Next, the hot clinker leaves the cement kiln and passes through a pre-cooling section at the outlet of the cement kiln at a temperature of about 1150°C to 1350°C. The hot clinker is then fed to a clinker cooler, where it is cooled to a temperature of about 80°C to 200°C by contacting the hot clinker with an air stream in counterflow or cross-counterflow. The thermal economy of the kiln system depends mainly on the efficiency of the cooling section.

[0003] When using a tube cooler, a planetary cooler or a satellite cooler, the hot air stream leaving the clinker cooler can be fully utilized as "secondary combustion air" in the cement kiln. In tube coolers, planetary coolers and satellite coolers, a split use of the hot air is usually not possible. Furthermore, the clinker throughput of tube coolers, planetary coolers and satellite coolers is limited to about 3000 t / d, which makes these types of clinker coolers less attractive for modern cement plants. Grate coolers are suitable for much higher throughputs of hot clinker of more than 10000 t / d and for a split use of the hot air obtained in the cooler for subsequent use, which is desirable. Grate coolers require more cooling air than is needed for subsequent use, e.g. as combustion air. A part of the hot air obtained from a grate cooler can be used as "secondary combustion air" in the cement kiln, just like in the case of tube coolers, planetary coolers and satellite coolers. Another part of the hot air can be used as "tertiary combustion air" in case the cement plant is equipped with a calciner as final part of the raw clinker preheating unit. In case the cement plant is not equipped with such a calciner, another part of the hot air (German: "Mittenluft") and the "tertiary combustion air" are either treated as waste gas or used for drying raw materials (such as coal and waste) or clinker raw meal used as primary fuel for the cement kiln. The moisture content of such raw materials ranges on average from about 5 wt.-% to about 8 wt.-%. The temperature of the hot air is about 900°C to 1100°C (when used as secondary air close to the grate cooler) or about 700°C to 1000°C (when used as tertiary combustion air, e.g. in a more distant optional calciner). In case the hot air is used for drying raw materials, the hot air has a temperature of about 250°C to 350°C, which means that a large part of the temperature is wasted before the hot air is used further. The "Mittenluft" can also be used for steam generation and / or power generation, however, such processes are less efficient. Thus, even when using modern grate coolers, the utilization of the heat generated in the form of hot air in the clinker cooler in a cement plant is still incomplete.

[0004] It is therefore an object of the present invention to provide a cement plant, in which the remaining unused part of the hot air and / or the inefficiently used hot air obtained from the clinker cooler is utilized in an economic way. It is a further object to provide a method for further utilizing the hot air obtained from a clinker cooler in a cement plant. SUMMARY

[0005] The problem of the incomplete utilization of the hot air obtained from a clinker cooler, preferably from a grate clinker cooler, is solved by a cement plant, comprising

[0006] (i) at least one cement kiln which is heated by combusting at least one fuel and in which hot clinker is formed from preheated raw meal,

[0007] (ii) at least one clinker cooler in which the hot clinker transfers heat to an air stream to form a hot air stream,

[0008] wherein the clinker cooler is downstream of and fluidly connected to the at least one cement kiln,

[0009] (iii) and at least one gasifier for producing a raw synthesis gas from a first feedstock by gasification, the raw synthesis gas optionally comprising a halogen,

[0010] wherein at least a portion of the hot air stream formed in step (ii) and the at least one gasifier are directly or indirectly thermally coupled.

[0011] The problem of not fully utilizing the hot air obtained from at least one clinker cooler, preferably from at least one grate clinker cooler, is further solved by a method for gasifying a first feedstock in at least one gasifier, the method comprising the steps of

[0012] (i) providing a cement plant comprising at least one cement kiln, at least one clinker cooler and at least one gasifier,

[0013] (ii) forming hot clinker in the at least one cement kiln,

[0014] (iii) cooling the hot clinker in at least one clinker cooler with an air stream and thereby forming a hot air stream,

[0015] (iv) transferring heat from at least a portion of the hot air stream to the at least one gasifier,

[0016] (v) forming a raw synthesis gas in the at least one gasifier, the raw synthesis gas optionally comprising a halogen.

[0017] preferably in step (iv),

[0018] a) adding at least a portion of the hot air leaving the at least one clinker cooler to the at least one gasifier, or

[0019] b1 ) transferring heat energy from at least a portion of the hot air leaving the at least one clinker cooler to a steam stream and / or an oxygen stream, and then feeding the steam stream and / or the oxygen stream to the at least one gasifier, or

[0020] b2) transferring heat energy from at least a portion of the hot air leaving the at least one clinker cooler to a first feedstock, and then feeding the first feedstock to the at least one gasifier.

[0021] Thus, in all three cases, at least a part of the hot air leaving the at least one clinker cooler and the at least one gasifier are directly or indirectly thermally coupled.

[0022] Feeding at least a part of the hot air into the at least one gasifier or feeding a preheated oxygen stream and / or a steam stream into the at least one gasifier or feeding a preheated first raw material into the at least one gasifier leads to a higher yield of the desired synthesis gas components H2and CO formed by the gasification reaction within the at least one gasifier, since less first raw material needs to be completely oxidized, for example, to CO2and H2O to provide the heat required for the gasification reaction.

[0023] Both the cement plant and the gasification method according to the present invention provide for an extended and more efficient utilization of the hot air formed in the clinker cooler, preferably in the grate clinker cooler, and thus provide for a more economic and more ecological production of cement. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A cement plant according to a first embodiment of the present invention is shown.

[0025] Figure 2 A cement plant according to a second and third aspect of the first embodiment of the present invention is shown.

[0026] Figure 3 A cement plant according to a second embodiment of the present invention is shown.

[0027] Figure 4 A cement plant according to a third embodiment of the present invention is shown.

[0028] Figure 5 A cement plant according to a fourth embodiment of the present invention is shown. DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the examples and the accompanying drawings, but the invention is not limited to these examples and any modification or alternative within the basic spirit of the invention is still within the scope of the invention as claimed. Furthermore, features of individual examples can also be combined into additional examples.

[0030] Definitions:

[0031] In the context of the present specification and the appended claims, the term "about" preferably means a deviation of ± 15% from the value thus described.

[0032] In the context of the present invention, the term "combinations thereof includes one or more of the recited elements.

[0033] In the context of the present invention, the term "mixtures thereof" includes one or more of the recited elements.

[0034] "Syngas" (also called "synthesis gas") means a mixture of mainly H2 and CO, which can be obtained by gasifying a feedstock in a gasifier.

[0035] The term "upstream of" is defined herein in relation to a series of unit operations as being located next to the side opposite to the direction of flow of the fluid passing through said series of unit operations.

[0036] The term "downstream of" is defined herein in relation to a series of unit operations as being located next to the side along the direction of flow of the fluid passing through said series of unit operations.

[0037] The term "in fluid connection with" in relation to two or more units is defined herein as fluid (such as solids, liquids, gases and mixtures thereof) can flow from one such unit to another such unit and through and / or along such analytical units. Two units that are "in fluid connection with" each other are connected, for example, by one or more pipes connected to each other or by a screw conveyor or by an extruder or by a solids pump.

[0038] The term "in physical connection with" means a direct ("physical") connection of two or more units, including a gasifier.

[0039] The term "thermally coupled" is defined herein as the ability of a component of two material streams, two units, a material stream and a unit, or more than two such list members to transfer heat from one list member to another such list member. For example, in the case where the material streams a and b are "thermally coupled", the hot material stream a can transfer heat to the cold material stream b, or in the case where the hot material stream and the gasifier are "thermally coupled", the hot material stream can transfer heat to a unit such as a gasifier.

[0040] The term "natural gas pipeline network" is defined herein as a pipe or a network of pipes for transporting natural gas and methane, or suitable for transporting natural gas and methane. The "natural gas pipeline network" is also called "natural gas network".

[0041] A preheated clinker raw mix (1) enters at least one cement kiln (2), in which the clinker raw mix (1) is converted by a thermo-chemical process into hot clinker (3), which leaves the at least one cement kiln in a downstream direction. The at least one cement kiln (2) is heated by combustion of at least one fuel together with combustion air.

[0042] At least one clinker cooler (4) is downstream of and fluidly connected to at least one cement kiln (2). Hot clinker (3) enters the at least one clinker cooler (4) and is contacted with an air stream (6). Next, cold clinker (5) exits the at least one clinker cooler (4) in a downstream direction and is further processed. Heat is transferred in the at least one clinker cooler (4) from the hot clinker (3) to the air stream (6), which exits the at least one clinker cooler (4) as a hot air stream (7).

[0043] The preheated clinker raw meal mixture (1) has a temperature of about 750 °C to about 850 °C when entering the at least one cement kiln (2). The preheated clinker raw meal mixture (1) is moved through the at least one cement kiln (2), which is typically a rotary kiln, at a temperature of about 1350 °C to about 1500 °C within about 20 min to about 40 min. The hot clinker exiting the at least one cement kiln (2) has a temperature of about 1150 °C to about 1350 °C, which is approximately the same temperature range as the hot clinker (3) when entering the at least one clinker cooler (4).

[0044] The clinker cooler (4) is preferably selected from the group comprising a tube cooler, a planetary cooler, a satellite cooler, and a grate cooler. Most preferably, the clinker cooler (4) is a grate cooler.

[0045] In case the clinker cooler (4) is a grate cooler, the hot clinker is transported horizontally through the cooler, and the air stream (6) is blown through the hot clinker (3) from a bottom region of the at least one clinker cooler (4) and exits the at least one clinker cooler (4) as a hot air stream (7) on a top section (= cross counter-current flow), or the air stream (6) is directed to the moving hot clinker (3) in a counter-current flow scheme. The temperature of the hot air stream (7) is preferably in the range of about 700 °C to about 1100 °C.

[0046] Next, at least a portion of the hot air stream (7) is used to provide heat for a gasification reaction in at least one gasifier (8). Thus, at least a portion of the hot air stream (7) is thermally coupled to the at least one gasifier (8). A first feedstock (9) enters the at least one gasifier (8), where it is converted to a raw synthesis gas (10) by a gasification reaction, which exits the at least one gasifier (8) in a downstream direction. The raw synthesis gas (10) optionally comprises a halogen.

[0047] The type of thermal coupling of at least a portion of the hot air stream to the at least one gasifier (8) depends on the type of gasifier(s) used in the cement plant and the method according to the present invention:

[0048] a) in a first aspect of the first embodiment, the at least one gasifier (8) is a fluidized bed gasifier, and the at least a portion of the hot air stream (7) is thermally coupled to the at least one gasifier (8) by means of a heat exchanger (11) that is in thermal contact with the at least one gasifier (8) and is in thermal contact with the at least a portion of the hot air stream (7).Figure 1 ), in case that the at least one gasifier (8) is selected from the group consisting of a counter-current fixed bed reactor, a co-current fixed bed reactor, a bubbling fluidized bed reactor and a circulating fluidized bed reactor and wherein at least a part of the hot air stream is added to the gasifier, at least a part of the hot air stream (7) is added to the at least one gasifier (8). In this case, at least a part of the hot air stream (7) transfers heat to the at least one gasifier (8), i.e. is directly thermally coupled with the at least one gasifier (8), and in addition acts as oxidizing agent in the gasification reaction, which is a partial oxidation reaction requiring at least one oxidizing agent, or

[0049] b1) in a second aspect of the first embodiment ( Figure 2 ), in case that the at least one gasifier is selected from the group consisting of a downer entrained flow reactor and an uper entrained flow reactor, heat is transferred from at least a part of the hot air stream (17) to the at least one gasifier (22) preferably by transferring heat from at least a part of the hot air stream (17) to a steam stream (20a) and / or an oxygen stream (20a) in at least one heat transfer device (18) to form a preheated steam stream (21a) and / or a hot oxygen stream (21a), which is then fed as oxidizing agent to the at least one gasifier (22), and wherein the at least a part of the hot air stream (17) and the at least one gasifier (22) are indirectly thermally coupled by the steam stream (20a) and / or the oxygen stream (20a), or

[0050] b2) in a third aspect of the first embodiment ( Figure 2 ), in case that the at least one gasifier (22) is selected from the group consisting of a downer entrained flow reactor and an uper entrained flow reactor, heat is transferred from at least a part of the hot air stream (17) to the at least one gasifier (22) by a heat transfer device (18), wherein heat from at least a part of the hot air stream (17) is transferred in the heat transfer device (18) to a first feedstock stream (20b) to form a preheated first feedstock stream (21b), which is then fed to the at least one gasifier (22), and wherein the at least a part of the hot air stream (17) and the at least one gasifier (22) are indirectly thermally coupled by the first feedstock stream (20b).

[0051] The second aspect b1) of the first embodiment and the third aspect b2) of the first embodiment are shown in Figure 2 .

[0052] In a first aspect, in case the at least one gasifier (8) is selected from the group consisting of a counter-current fixed bed reactor, a co-current fixed bed reactor, a bubbling fluidized bed reactor and a circulating fluidized bed reactor (e.g. with at least one burner), at least a portion of the hot air stream (7) is added to the at least one gasifier (8). Other suitable means for adding a hot air stream to such a gasifier are known in the art and can be chosen accordingly.

[0053] In a second aspect of the first embodiment of the present invention, Figure 2 In a second aspect of the first embodiment of the present invention, the clinker raw meal mixture (1 1 ) enters at least one cement kiln (12) and hot clinker (13) exits the at least one cement kiln (12) in a downstream direction. Next, the hot clinker (13) enters a clinker cooler (14) downstream of and fluidly connected to the at least one cement kiln (12). The hot clinker (13) is cooled in the clinker cooler (14) by an air stream (16). Cold clinker (15) exits the clinker cooler (14) in a downstream direction. At least a portion of a hot air stream (17) also exits the clinker cooler (14) and is added to at least one heat transfer device (18) fluidly connected to the clinker cooler (14). A steam stream (20a) and / or an oxygen stream (20a) also enter the at least one heat transfer device (18). Heat is transferred within the at least one heat transfer device (18) from the at least a portion of the hot air stream (17) to the steam stream (20a) and / or the oxygen stream (20a). A cold air stream (19) and a preheated steam stream (21 a) and / or a hot oxygen stream (21 a) exit the at least one heat transfer device (18) through a cold air stream (19) outlet and a preheated steam (21 a) outlet and / or a hot oxygen stream (21 a) outlet, respectively. The preheated steam (21 a) and / or the hot oxygen stream (21 a) then enter at least one gasifier (22) downstream of and fluidly connected to the preheated steam (21 a) outlet and / or the hot oxygen stream (21 a) outlet. The preheated steam stream (21 a) and / or the hot oxygen stream (21 a) act as an oxidizing agent for a gasification reaction within the at least one gasifier (22). A first feedstock stream (23a) enters the at least one gasifier (22) and is converted in the gasification reaction with the preheated steam stream and / or the hot oxygen stream (21 a) to a raw synthesis gas stream (24) which exits the at least one gasifier (22) in a downstream direction. The raw synthesis gas stream (24) optionally comprises a halogen.

[0054] Preferably, the steam stream (20a) is heated in the at least one heat transfer device by at least a portion of the hot air stream (17) before entering the at least one gasifier (22) as a preheated steam stream (21a). More preferably, the oxygen stream (20a) is heated in the at least one heat transfer device by at least a portion of the hot air stream (17) before entering the at least one gasifier (22) as a hot oxygen stream (21a). Most preferably, heat is transferred in a first heat transfer device from at least a portion of the hot air stream to the steam stream, and then heat is transferred in a second heat transfer device from at least a portion of the hot air stream to the oxygen stream.

[0055] In this second aspect of the first embodiment, the at least one gasifier (22) is preferably selected from the group consisting of a downflow entrained flow reactor and an upflow entrained flow reactor.

[0056] In the second aspect of the first embodiment, the at least one heat transfer device (18) is preferably a heat exchanger suitable for transferring heat from a first gaseous stream to a second gaseous stream. The heat transfer device (18) is more preferably selected from the group comprising a tube-in-tube heat exchanger, a shell-and-tube heat exchanger, a plate heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, and a waste heat recovery unit. Suitable flow arrangements include counterflow flow, crossflow flow, and the like.

[0057] In the case where heat is transferred from at least a portion of the hot air stream to the oxygen stream and the steam stream, preferably heat is transferred in a first heat transfer device from at least a portion of the hot air stream to the steam stream, and then heat is transferred in a second heat transfer device from at least a portion of the hot air stream to the oxygen stream. More preferably, the first heat transfer device is a heat exchanger suitable for transferring heat from a first gaseous stream to a second gaseous stream, and the second heat transfer device is a heat exchanger suitable for transferring heat from a first gaseous stream to a second gaseous stream. Most preferably, the first heat transfer device is selected from the group comprising a tube-in-tube heat exchanger, a shell-and-tube heat exchanger, a plate heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, and a waste heat recovery unit. Most preferably, the second heat transfer device is selected from the group comprising a tube-in-tube heat exchanger, a shell-and-tube heat exchanger, a plate heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, and a waste heat recovery unit. For the first heat transfer device and the second heat transfer device, suitable flow arrangements include counterflow flow, crossflow flow, and the like.

[0058] In a third aspect of the first embodiment of the present invention, Figure 2), the clinker raw meal mixture (11) enters at least one cement kiln (12), and hot clinker (13) exits the at least one cement kiln (12) in a downstream direction. Next, the hot clinker (13) enters a clinker cooler (14) downstream of and fluidly connected to the at least one cement kiln (12). The hot clinker (13) is cooled in the clinker cooler (14) by a stream of air (16). Cold clinker (15) exits the clinker cooler (14) in a downstream direction. At least a portion of the stream of hot air (17) also exits the clinker cooler (14) and is fed into a heat transfer device (18) fluidly connected to the clinker cooler (14). A first raw material stream (20b) also enters the heat transfer device (18). Heat is transferred within the heat transfer device (18) from the at least a portion of the stream of hot air (17) to the first raw material stream (20b). A stream of cold air (19) and a preheated first raw material stream (21b) exit the heat transfer device (18) through a stream of cold air (19) outlet and a preheated first raw material stream (21b) outlet, respectively. The preheated first raw material stream (21b) then enters at least one gasifier (22) downstream of and fluidly connected to the preheated first raw material stream (21b) outlet. The preheated first raw material stream (21b) enters the at least one gasifier (22) and is converted in a gasification reaction to a raw synthesis gas stream (24) with a stream of oxygen (23b) that is also fed into the at least one gasifier (22) and acts as an oxidizing agent, the raw synthesis gas stream exiting the at least one gasifier (22) in a downstream direction. The raw synthesis gas stream (24) optionally comprises a halogen.

[0059] In this third aspect of the first embodiment, the at least one gasifier (22) is preferably selected from the group consisting of a downflow entrained flow reactor and an upflow entrained flow reactor.

[0060] The heat transfer device (18) is preferably a heat exchanger suitable for transferring heat from a gaseous stream (at least a portion of the stream of hot air (17)) to a solid and / or liquid first raw material stream (20b). Suitable heat exchangers include direct contact heat exchangers, plate heat exchangers, tube heat exchangers, and the like. Suitable heat exchangers for transferring heat from a gaseous stream (at least a portion of the stream of hot air (17)) to a solid and / or liquid first raw material (20b) are known in the art and can be selected accordingly. Suitable flow arrangements include counterflow flow, crossflow flow, and the like.

[0061] In a second embodiment of the present invention ( Figure 3 ), the cement plant comprises at least one cement kiln, at least one clinker cooler, and at least one gasifier.

[0062] The preheated clinker raw meal mixture (31) enters at least one cement kiln (32), in which the clinker raw meal mixture (31) is converted by a thermochemical process into hot clinker (33), which leaves the at least one cement kiln (32) in a downstream direction. The at least one cement kiln (32) is heated by combustion of at least one fuel.

[0063] At least one clinker cooler (34) is downstream of and fluidly connected to the at least one cement kiln (32). The hot clinker (33) enters the at least one clinker cooler (34) and is contacted with an air stream (36). Next, cold clinker (35) leaves the at least one clinker cooler (34) in a downstream direction and is further processed. Heat is transferred in the at least one clinker cooler (34) from the hot clinker (33) to the air stream (36), which leaves the at least one clinker cooler (34) as a hot air stream (37).

[0064] The preheated clinker raw meal mixture (31) has a temperature of about 750°C to about 850°C when entering the at least one cement kiln (32). The preheated clinker raw meal mixture (31) is moved through the at least one cement kiln (32), which is typically a rotary kiln, at a temperature of about 1350°C to about 1500°C within about 20 min to about 40 min. The hot clinker leaving the at least one cement kiln (32) has a temperature of about 1150°C to about 1350°C, which is approximately the same temperature range as the hot clinker (33) when entering the at least one clinker cooler (34).

[0065] The clinker cooler (34) is preferably a grate cooler, through which the hot clinker is transported horizontally, and an air stream (36) is blown through the hot clinker (33) from a bottom region of the at least one clinker cooler (34) (= cross counter-current flow) or is directed towards the moving hot clinker (33) in a counter-current flow scheme and leaves the at least one clinker cooler (34) as a hot air stream (37) on a top section. The temperature of the hot air stream (37) is preferably in the range of about 700°C to about 1100°C.

[0066] Next, at least a portion of the hot air stream (37) is used to provide heat for a gasification reaction in at least one gasifier (38). Thus, at least a portion of the hot air stream (37) is thermally coupled to the at least one gasifier (38). A first feedstock (40) enters the at least one gasifier (38), in which the first feedstock (40) is converted by a gasification reaction into a raw synthesis gas (41), which leaves the at least one gasifier (38) in a downstream direction.

[0067] The first portion of the crude synthesis gas stream (43) is then separated from the crude synthesis gas stream (41) in an optional synthesis gas stream splitter (42). The first portion of the crude synthesis gas stream (43) can be used, for example, as a feedstock for the (petro)chemical industry and for the production of, for example, methane, methanol and Fischer-Tropsch hydrocarbons.

[0068] A second portion of the crude syngas (44) is separated from the crude syngas (41) in an optional syngas splitter (42). The second crude syngas (44) is then used as supplementary fuel for at least one cement kiln (32). Thus, at least a portion of the crude syngas (44) formed in at least one gasifier (38) is used as fuel to heat at least one cement kiln (32) by burning said fuel.

[0069] The thermal coupling type between at least a portion of the hot airflow and at least one gasifier depends on the type of one or more gasifiers used in the cement plant according to the present invention:

[0070] a) In the case where at least one gasifier (38) is selected from the group consisting of a countercurrent fixed-bed reactor, a co-current fixed-bed reactor, a bubbling fluidized-bed reactor, and a circulating fluidized-bed reactor, and where at least a portion of a hot air stream is added to the gasifier, at least a portion of a hot air stream (37) is added to at least one gasifier (38). In this case, at least a portion of the hot air stream (37) transfers heat to at least one gasifier (38), i.e., is directly thermally coupled to at least one gasifier (38), and further acts as an oxidant (which is a partial oxidation reaction requiring at least one oxidant), or

[0071] b1) In the case where at least one gasifier is selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor, heat is preferably transferred from at least a portion of the hot air flow (37) to the gasifier in the following manner (second aspect of the second embodiment). Figure 3 (Not shown): In at least one heat transfer device, at least a portion of the heat from a hot air stream (37) is transferred to a steam stream and / or an oxygen stream to form a preheated steam stream and / or a hot oxygen stream, wherein the preheated steam stream and / or hot oxygen stream is then fed into at least one gasifier and acts as an oxidant, and wherein at least a portion of the hot air stream and at least one gasifier are indirectly thermally coupled via the steam stream and / or oxygen stream, or

[0072] b2) In the case where at least one gasifier is selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor, heat is transferred from at least a portion of the hot air flow (37) to at least one gasifier (third aspect of the second embodiment) via a heat transfer device. Figure 3wherein heat from at least a portion of the hot air stream is transferred through the heat transfer device to the first feedstock stream to form a preheated first feedstock stream, which is then fed into the at least one gasifier, and wherein the at least a portion of the hot air stream and the at least one gasifier are indirectly heat coupled by the first feedstock stream.

[0073] In case the at least one gasifier (38) is selected from the group consisting of a counter-current fixed bed reactor, a co-current fixed bed reactor, a bubbling fluidized bed reactor and a circulating fluidized bed reactor (e.g. with at least one burner), at least a portion of the hot air stream (37) can be added to the at least one gasifier (38). Other suitable means for adding a hot air stream to such a gasifier are known in the art and can be chosen accordingly.

[0074] In a second aspect of the second embodiment of the present invention, the clinker raw meal mixture (31) enters the at least one cement kiln (32), and a hot clinker (33) exits the at least one cement kiln (32) in a downstream direction. Next, the hot clinker (33) enters a clinker cooler (34) downstream of and fluidly connected to the at least one cement kiln (32). The hot clinker (33) is cooled in the clinker cooler (34) by an air stream (36). A cold clinker (35) exits the clinker cooler (34) in a downstream direction. A hot air stream (37) also exits the clinker cooler (34) and is added to at least one heat transfer device (39) fluidly connected to the clinker cooler (34). Figure 3 A steam stream and / or an oxygen stream (41) also enters the at least one heat transfer device. Heat is transferred within the at least one heat transfer device from at least a portion of the hot air stream (37) to the steam stream and / or the oxygen stream. A cold air stream (42) and a preheated steam stream and / or hot oxygen stream (43) exit the at least one heat transfer device through a cold air stream outlet and a preheated steam stream outlet and / or hot oxygen stream outlet, respectively. Figure 3 A steam stream and / or an oxygen stream (41) also enters the at least one heat transfer device. Heat is transferred within the at least one heat transfer device from at least a portion of the hot air stream (37) to the steam stream and / or the oxygen stream. A cold air stream (42) and a preheated steam stream and / or hot oxygen stream (43) exit the at least one heat transfer device through a cold air stream outlet and a preheated steam stream outlet and / or hot oxygen stream outlet, respectively. Figure 3 A steam stream and / or an oxygen stream (41) also enters the at least one heat transfer device. Heat is transferred within the at least one heat transfer device from at least a portion of the hot air stream (37) to the steam stream and / or the oxygen stream. A cold air stream (42) and a preheated steam stream and / or hot oxygen stream (43) exit the at least one heat transfer device through a cold air stream outlet and a preheated steam stream outlet and / or hot oxygen stream outlet, respectively. Figure 3 A steam stream and / or an oxygen stream (41) also enters the at least one heat transfer device. Heat is transferred within the at least one heat transfer device from at least a portion of the hot air stream (37) to the steam stream and / or the oxygen stream. A cold air stream (42) and a preheated steam stream and / or hot oxygen stream (43) exit the at least one heat transfer device through a cold air stream outlet and a preheated steam stream outlet and / or hot oxygen stream outlet, respectively.

[0075] In this second aspect of the second embodiment, the at least one gasifier (38) is preferably selected from the group consisting of a downer entrained flow reactor and an uper entrained flow reactor.

[0076] Preferably, the steam stream is heated in the at least one heat transfer device by at least a portion of the hot air stream (37) before entering the at least one gasifier (38) as a preheated steam stream. More preferably, the oxygen stream is heated in the at least one heat transfer device by at least a portion of the hot air stream (37) before entering the at least one gasifier (38) as a hot oxygen stream. Most preferably, heat is transferred in a first heat transfer device from at least a portion of the hot air stream to the steam stream, and then heat is transferred in a second heat transfer device from at least a portion of the hot air stream to the oxygen stream.

[0077] The at least one heat transfer device is preferably a heat exchanger suitable for transferring heat from a first gaseous stream to a second gaseous stream. The heat transfer device (18) is more preferably selected from the group consisting of a tube-in-tube heat exchanger, a shell-and-tube heat exchanger, a plate heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, and a waste heat recovery unit. Suitable flow arrangements include counterflow flow, crossflow flow, and the like.

[0078] In the case where heat is transferred from at least a portion of the hot air stream to the oxygen stream and the steam stream, preferably heat is transferred in a first heat exchanger device from at least a portion of the hot air stream to the steam stream, and then heat is transferred in a second heat transfer device from at least a portion of the hot air stream to the oxygen stream. More preferably, the first heat transfer device is a heat exchanger suitable for transferring heat from a first gaseous stream to a second gaseous stream, and the second heat transfer device is a heat exchanger suitable for transferring heat from a first gaseous stream to a second gaseous stream. Most preferably, the first heat transfer device is selected from the group consisting of a tube-in-tube heat exchanger, a shell-and-tube heat exchanger, a plate heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, and a waste heat recovery unit. Most preferably, the second heat transfer device is selected from the group consisting of a tube-in-tube heat exchanger, a shell-and-tube heat exchanger, a plate heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, and a waste heat recovery unit. Suitable flow arrangements for the first heat transfer device and the second heat transfer device include counterflow flow, crossflow flow, and the like.

[0079] In a third aspect of the second embodiment of the present invention, the clinker raw meal mixture (31) enters the at least one cement kiln (32), and hot clinker (33) exits the at least one cement kiln (32) in a downstream direction. Next, the hot clinker (33) enters a clinker cooler (34) downstream of and fluidly connected to the at least one cement kiln (32). The hot clinker (33) is cooled in the clinker cooler (34) by an air stream (36). Cold clinker (35) exits the clinker cooler (34) in a downstream direction. At least a portion of the hot air stream (37) also exits the clinker cooler (34) and is added to a heat transfer device (18) fluidly connected to the clinker cooler (34). The at least one heat transfer device (18) is suitable for transferring heat from a first gaseous stream to a second gaseous stream. The first gaseous stream is the hot air stream (37) and the second gaseous stream is the steam stream (39) and / or the oxygen stream (40). The at least one heat transfer device (18) is selected from the group consisting of a tube-in-tube heat exchanger, a shell-and-tube heat exchanger, a plate heat exchanger, a plate-fin heat exchanger, a microchannel heat exchanger, and a waste heat recovery unit. Suitable flow arrangements include counterflow flow, crossflow flow, and the like. Figure 3(Not shown in the image) In the first raw material stream ( Figure 3 (Not shown in the image) also enters the heat transfer device. Heat is transferred within the heat transfer device from at least a portion of the hot air stream (37) to the first raw material stream. The cold air stream and the preheated first raw material stream ( Figure 3 (Not shown) The feedstock exits the heat transfer device through a cold air outlet and a preheated first feedstock outlet, respectively. The preheated first feedstock is then fed into at least one gasifier (38) downstream of and fluidly connected to the preheated first feedstock outlet, and is converted into a crude synthesis gas stream (41) by an oxygen stream (as an oxidant for the gasification reaction) in the gasification reaction. The crude synthesis gas stream exits the at least one gasifier (38) in a downstream direction.

[0080] In this third aspect of the second embodiment, at least one gasifier (38) is preferably selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor.

[0081] The heat transfer device is preferably a heat exchanger suitable for transferring heat from a gaseous flow (at least a portion of the hot air flow (37)) to a solid and / or liquid feedstock flow. Suitable heat exchangers include direct contact heat exchangers, plate heat exchangers, tubular heat exchangers, etc. Suitable heat exchangers for transferring heat from a gaseous flow (at least a portion of the hot air flow (37)) to a solid and / or liquid feedstock are known in the art and can be selected accordingly. Suitable flow arrangements include countercurrent flow, crossflow, etc.

[0082] In the third embodiment of the present invention ( Figure 4 In a cement plant, there is at least one cement kiln, at least one clinker cooler, at least one gasifier, and at least one dehalogenation unit.

[0083] The preheated raw and cooked food mixture (51) enters at least one dehalogenation unit (52) and exits the at least one dehalogenation unit (52) downstream as a halogen-loaded cooked food stream (53). The dehalogenation unit (52) is located in the preheating unit for the raw and cooked food mixture. Figure 4 Downstream of and fluidly connected to the preheated clinker-raw mixture (51), the preheated clinker-raw mixture (51) leaves the preheating unit and enters the dehalogenation unit (52) at a temperature of about 800°C to about 850°C. The preheating unit is preferably a multi-stage cyclone separator system, such as a four-stage, five-stage, or six-stage cyclone separator preheater.

[0084] The halogen-loaded clinker stream (53) then enters at least one cement kiln (54), in which the halogen-loaded clinker stream (53) is converted by a thermochemical process into hot clinker (55), which leaves the at least one cement kiln (54) in downstream direction or first enters an optional calciner (calcination unit) and then enters the at least one cement kiln (54). The at least one cement kiln (54) is downstream and fluidly connected to the at least one dehalogenation unit (52) or downstream and fluidly connected to the optional calciner and in both cases is preferably heated by combustion of at least one fuel.

[0085] At least one clinker cooler (56) is downstream and fluidly connected to the at least one cement kiln (54). The hot clinker (55) enters the at least one clinker cooler (56) and is in contact with an air stream (58). Next, the cold clinker (57) leaves the at least one clinker cooler (56) in downstream direction and is further processed. Heat is transferred in the at least one clinker cooler (56) from the hot clinker (55) to the air stream (58), which leaves the at least one clinker cooler (56) as a hot air stream (59).

[0086] The halogen-loaded clinker (53) has a temperature of about 700 °C to about 900 °C when entering the at least one cement kiln (54). The halogen-loaded clinker (53) is moved through the at least one cement kiln (54), which is typically a rotary kiln, at a temperature of about 1350 °C to about 1500 °C within about 20 min to about 40 min. The hot clinker (57) leaving the at least one cement kiln (54) has a temperature of about 1150 °C to about 1350 °C, which is approximately the same temperature range as the hot clinker (55) has when entering the at least one clinker cooler (57).

[0087] The clinker cooler (56) is preferably a grate cooler, through which the hot clinker is transported horizontally and through which an air stream (58) is blown from a bottom region of the at least one clinker cooler (56) through the hot clinker (55) (= cross counterflow flow) or is directed towards the moving hot clinker (55) in a counterflow flow regime. The temperature of the hot air stream (59) is in the range of about 700 °C to about 1100 °C.

[0088] Next, at least a part of the hot air stream (59) is used to provide heat for a gasification reaction in at least one gasifier (60). Thus, at least a part of the hot air stream (59) is thermally coupled to the at least one gasifier (60). A first feedstock (61) enters the at least one gasifier (60), in which the first feedstock (61) is converted by a gasification reaction into a raw synthesis gas (62), which comprises halogen, which leaves the at least one gasifier (60) in downstream direction.

[0089] The crude synthesis gas (62) is then fed to a dehalogenation unit (52) in which the crude synthesis gas is contacted with the preheated clinker raw meal mixture (51). The dehalogenation unit (52) can be, for example, a device for conveying the preheated clinker raw meal mixture (51) and at the same time contacting the crude synthesis gas (62) with the preheated clinker raw meal mixture (51). The dehalogenation unit (52) can also be a cyclone, such as one of the cyclones for preheating the clinker raw meal mixture or an additional cyclone. The preheated clinker raw meal mixture (51) is contacted with the crude synthesis gas (62) in such a cyclone and thereby at least a portion of the halogen in the crude synthesis gas (62) is transferred to the preheated clinker raw meal mixture (51). The crude synthesis gas (62) comprises halogen-containing compounds ("halogen") as impurities, which react, for example, with alkali metals (ions) present on and in the surface of the preheated clinker raw meal mixture (51) and thereby form alkali metal halides in the at least one dehalogenation unit (52). Thereby, the crude synthesis gas (62) is converted into an at least partially dehalogenated synthesis gas (63). The preheated clinker raw meal mixture (51) acts as a moving bed within the at least one dehalogenation unit (52). The preheated clinker raw meal mixture (51) and the crude synthesis gas (62) can be contacted within the at least one dehalogenation unit (52) in the same direction (co-current flow), cross counter-current, or in opposite directions (counter-current flow). Preferably, the clinker raw meal mixture (51) and the crude synthesis gas (62) are contacted in counter-current flow.

[0090] Thus, the cement plant further comprises a device for preheating raw clinker meal mixture and a device for contacting said preheated raw clinker meal mixture with said crude synthesis gas comprising halogen, thereby transferring at least a portion of said halogen from said crude synthesis gas to said pre-treated clinker, and wherein the device for contacting said preheated raw clinker meal mixture with said crude synthesis gas comprising halogen has an inlet for preheated raw clinker meal mixture and an outlet, and wherein said inlet for preheated raw clinker meal mixture is downstream of and fluidly connected to said device for preheating raw clinker meal mixture, and wherein said at least one cement kiln is downstream of and fluidly connected to said outlet for preheated raw clinker meal mixture.

[0091] The halogen component of the halogen-containing compounds is converted, for example, into alkali metal halides (such as NaCI and KCI), which are then decomposed in the at least one cement kiln (54). The halogen is removed from the at least one cement kiln (54) as part of the combusted fuel exhaust stream and re-enters the preheating unit as hot gas. Thus, the halides transferred from the crude synthesis gas (62) to the preheated clinker raw meal mixture (53) become part of an "internal halide cycle" of the cement plant.

[0092] The type of heat coupling of at least one part of the hot air stream and the at least one gasifier depends on the type of gasifier used in the cement plant according to the present application:

[0093] a) In case the at least one gasifier (60) is selected from the group consisting of a counter-current fixed bed reactor, a co-current fixed bed reactor, a bubbling fluidized bed reactor and a circulating fluidized bed reactor and wherein at least one part of the hot air stream is added to the gasifier, at least one part of the hot air stream (59) can be added to the at least one gasifier (60). In this case, at least one part of the hot air stream (59) transfers heat to the at least one gasifier (60), i.e. is directly heat coupled with the at least one gasifier (60), and in addition acts as oxidizing agent (which is part of the partial oxidation reaction requiring at least one oxidizing agent), or

[0094] b1) In case the at least one gasifier (60) is selected from the group consisting of a downer entrained flow reactor and an uper entrained flow reactor, heat is transferred from at least one part of the hot air stream (59) to the at least one gasifier (60) by transferring heat from at least one part of the hot air stream in at least one heat transfer device to a steam stream and / or an oxygen stream to form a preheated steam stream and / or a hot oxygen stream, which is then fed to the at least one gasifier and acts as oxidizing agent, and wherein the at least one part of the hot air stream and the at least one gasifier are indirectly heat coupled via the steam stream and / or the hot oxygen stream (second aspect of the third embodiment, not shown in Figure 4 b2) In case the at least one gasifier is selected from the group consisting of a downer entrained flow reactor and an uper entrained flow reactor, heat is transferred from at least one part of the hot air stream (59) to the at least one gasifier by transferring heat from at least one part of the hot air stream in a heat transfer device to a first feedstock stream to form a preheated first feedstock stream, and wherein the at least one part of the hot air stream and the at least one gasifier are indirectly heat coupled via the first feedstock stream (third aspect of the third embodiment, not shown in

[0095] Figure 4

[0096] In case the at least one gasifier (60) is selected from the group consisting of a counter-current fixed bed reactor, a co-current fixed bed reactor, a bubbling fluidized bed reactor and a circulating fluidized bed reactor (e.g. with at least one burner), at least one part of the hot air stream (59) can be added to the at least one gasifier (60). Other suitable means for adding at least one part of the hot air stream to such a gasifier are known in the art and can be chosen accordingly.

[0097] ​​In the second and third aspects of the third embodiment of the invention, a preheated clinker-raw meal mixture (51) enters at least one dehalogenation unit (52) and exits the at least one dehalogenation unit (52) as a halogen-loaded clinker stream (53) in a downstream direction. The halogen-loaded clinker stream (53) then enters at least one cement kiln (54), in which the halogen-loaded clinker stream (53) is converted into hot clinker (55) by a thermochemical process, which exits the at least one cement kiln (54) in a downstream direction. The at least one cement kiln (54) is downstream of and fluidly connected to the at least one dehalogenation unit (52) and is heated by the combustion of at least one fuel.

[0098] In a second aspect of the third embodiment, at least a portion of the hot airflow (59) exits the clinker cooler (56) and is incorporated into at least one heat transfer device fluidly connected to the clinker cooler (56). Figure 4 (Not shown in the image). Steam and / or oxygen streams also enter the heat transfer device. Heat is transferred from at least a portion of the hot air stream (59) to the steam and / or oxygen stream within at least one heat transfer device. The cold air stream and the preheated steam and / or hot oxygen stream exit the at least one heat transfer device through the cold air stream outlet and the preheated steam stream outlet and / or hot oxygen stream outlet, respectively. The preheated steam and / or hot oxygen stream then enters at least one gasifier (60) downstream of and fluidly connected to the preheated steam stream outlet and / or hot oxygen stream outlet. The preheated steam and / or hot oxygen stream acts as an oxidant for the gasification reaction within the at least one gasifier (60). A first feed stream (61) enters the at least one gasifier (60) and is converted into a crude synthesis gas stream (62) in the gasification reaction by the preheated steam and / or hot oxygen stream, which exits the at least one gasifier (60) in a downstream direction.

[0099] In this second aspect of the second embodiment, at least one gasifier (60) is preferably selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor.

[0100] Preferably, the steam stream is heated in at least one heat transfer device by at least a portion of the hot air stream (59), and then enters at least one gasifier (60) as a preheated steam stream. More preferably, the oxygen stream is heated in at least one heat transfer device by at least a portion of the hot air stream (59), and then enters at least one gasifier (60) as a hot oxygen stream. Most preferably, heat is transferred from at least a portion of the hot air stream to the steam stream in a first heat transfer device, and then heat is transferred from at least a portion of the hot air stream to the oxygen stream in a second heat transfer device.

[0101] At least one heat transfer device is preferably a heat exchanger suitable for transferring heat from a first gaseous flow to a second gaseous flow. The heat transfer device (18) is more preferably selected from the group consisting of: shell-and-tube heat exchangers, tube-and-shell heat exchangers, plate heat exchangers, plate-fin heat exchangers, microchannel heat exchangers, and waste heat recovery units. Suitable flow arrangements include countercurrent flow, crossflow, etc.

[0102] In cases where heat is transferred from at least a portion of the hot air stream to the oxygen stream and the steam stream, it is preferable that the heat is transferred from at least a portion of the hot air stream to the steam stream in a first heat exchange device, and then the heat is transferred from at least a portion of the hot air stream to the oxygen stream in a second heat transfer device. More preferably, the first heat transfer device is a heat exchanger suitable for transferring heat from a first gaseous stream to a second gaseous stream, and the second heat transfer device is a heat exchanger suitable for transferring heat from the first gaseous stream to the second gaseous stream. Most preferably, the first heat transfer device is selected from the group consisting of: shell-and-tube heat exchangers, shell-and-tube heat exchangers, plate heat exchangers, plate-fin heat exchangers, microchannel heat exchangers, and waste heat recovery units. Most preferably, the second heat transfer device is selected from the group consisting of: shell-and-tube heat exchangers, shell-and-tube heat exchangers, plate heat exchangers, plate-fin heat exchangers, microchannel heat exchangers, and waste heat recovery units. Suitable flow arrangements for the first and second heat transfer devices include counter-current flow, cross-flow, etc.

[0103] In a third aspect of the third embodiment of the invention, at least a portion of the hot air stream (59) exits the clinker cooler (56) and is incorporated into a heat transfer device fluidly connected to the clinker cooler (56). Figure 4 (Not shown in the image) In the first raw material stream ( Figure 4 (Not shown) also enters the heat transfer device. Heat is transferred within the heat transfer device from at least a portion of the hot air stream (59) to the first feed stream. The cold air stream and the preheated first feed stream exit the heat transfer device through the cold air stream outlet and the preheated first feed stream outlet, respectively. The preheated first feed stream is then fed into at least one gasifier (60) downstream of and fluidly connected to the preheated first feed stream outlet of the heat transfer device, and in the gasification reaction, the oxygen stream also fed into the at least one gasifier is converted into a crude synthesis gas stream (62), which exits the at least one gasifier (60) in a downstream direction.

[0104] In this third aspect of the third embodiment, at least one gasifier (60) is preferably selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor.

[0105] The heat transfer device is preferably a heat exchanger suitable for transferring heat from a gaseous flow (at least a portion of the hot air flow (59)) to a solid and / or liquid first feedstock flow. Suitable heat exchangers include direct contact heat exchangers, plate heat exchangers, tubular heat exchangers, etc. Suitable heat exchangers for transferring heat from a gaseous flow (at least a portion of the hot air flow (59)) to a solid and / or liquid first feedstock are known in the art and can be selected accordingly. Suitable flow arrangements include countercurrent flow, crossflow, etc.

[0106] The halogen-loaded clinker (53) has a temperature of about 700°C to about 900°C when it enters at least one cement kiln (54). The halogen-loaded clinker (53) moves through at least one cement kiln (54) at a temperature of about 1350°C to about 1500°C over about 20 min to about 40 min, which is typically a rotary kiln. The hot clinker (55) leaving at least one cement kiln (54) has a temperature of about 1150°C to about 1350°C, which is approximately the same temperature range as the hot clinker (55) when it enters at least one clinker cooler (56).

[0107] The crude syngas (62) is then added to the dehalogenation unit (52), where it is contacted with the clinker-raw meal mixture (51). The crude syngas (62) contains halogenated compounds (“halogens”) as impurities, which react with alkali metal (ions) present on and within the preheated clinker-raw meal mixture, forming alkali metal halides in at least one dehalogenation unit (52). Thus, the crude syngas (62) is converted into at least partially dehalogenated syngas (63). The clinker-raw meal mixture (51) acts as a moving bed within at least one dehalogenation unit (52). The clinker-raw meal mixture (51) and the crude syngas (62) can be contacted in the same direction (co-current flow) or in opposite directions (counter-current flow) within at least one dehalogenation unit (52). Preferably, the clinker-raw meal mixture (51) and the crude syngas (62) are contacted in counter-current flow.

[0108] At least a portion of the hot air stream (59), excluding the combustion air, serves as the heat source for the gasification reaction of the feedstock in at least one gasifier. Furthermore, in the case where at least one gasifier is selected from the group consisting of a counter-current fixed-bed reactor, a co-current fixed-bed reactor, a bubbling fluidized-bed reactor, and a circulating fluidized-bed reactor, at least a portion of the hot air stream also serves as the oxidant in the gasification reaction. Additionally, the preheated clinker-raw mixture (53) is used as a reactant for halogens in the crude syngas (62) and provides the heat energy required for the dehalogenation. Thus, at least partially dehalogenated syngas (63) is obtained economically.

[0109] In the fourth embodiment of the present invention (Figure 5 In a cement kiln (72), a preheated clinker-raw meal mixture (71) is fed into at least one cement kiln (72), where the clinker-raw meal mixture (71) is converted into hot clinker (73) through a thermochemical process, which exits the at least one cement kiln in a downstream direction. The at least one cement kiln (72) is heated by the combustion of at least one fuel.

[0110] At least one clinker cooler (74) is downstream of and fluidly connected to at least one cement kiln (72). Hot clinker (73) enters at least one clinker cooler (74) and comes into contact with an airflow (76). Next, cold clinker (75) exits at least one clinker cooler (74) in a downstream direction and is further processed. Heat is transferred from the hot clinker (73) to the airflow (76) within at least one clinker cooler (74), which exits at least one clinker cooler (74) as a hot airflow (77).

[0111] The preheated clinker-raw meal mixture (71) has a temperature of about 750°C to about 850°C when it enters at least one cement kiln (72). The preheated clinker-raw meal mixture (71) moves through at least one cement kiln (72) at a temperature of about 1350°C to about 1500°C for about 20 min to about 40 min, which is typically a rotary kiln. The hot clinker (73) leaving at least one cement kiln (72) has a temperature of about 1150°C to about 1350°C, which is approximately the same temperature range as the hot clinker (73) when it enters at least one clinker cooler (74).

[0112] The clinker cooler (74) is preferably a grate cooler through which hot clinker is transported horizontally, and an airflow (76) is blown, for example, from the bottom region of at least one clinker cooler (74) through the hot clinker (73) and exits at least one clinker cooler (74) as a hot airflow (77) at the top section (= cross-current flow), or the airflow (76) is directed toward the moving hot clinker (73) in a counter-current flow pattern. The temperature of the hot airflow (77) is in the range of about 700°C to about 1100°C.

[0113] Next, at least a portion of the hot air stream (77) is used to provide heat for the gasification reaction in at least one gasifier (78). Thus, at least a portion of the hot air stream (77) is thermally coupled to at least one gasifier (78). A first feedstock (79) enters at least one gasifier (78), in which the first feedstock (79) is converted into crude syngas (80) through a gasification reaction, which exits at least one gasifier (78) in a downstream direction.

[0114] The type of thermal coupling between at least a portion of the hot airflow and at least one gasifier depends on the type of gasifier used in the cement plant according to the invention:

[0115] a) In a first aspect of the fourth embodiment, where at least one gasifier (78) is selected from the group consisting of a countercurrent fixed-bed reactor, a co-current fixed-bed reactor, a bubbling fluidized-bed reactor, and a circulating fluidized-bed reactor, and wherein at least a portion of a hot air stream is added to the gasifier, at least a portion of a hot air stream (77) may be added to the at least one gasifier (78). In this case, at least a portion of the hot air stream (77) transfers heat to the at least one gasifier (78), i.e., is directly thermally coupled to the at least one gasifier (78), and further acts as an oxidant (which is a partial oxidation reaction requiring at least one oxidant), or

[0116] b1) In the second aspect of the fourth embodiment ( Figure 5 (Not shown in the image) In the case where at least one gasifier is selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor, heat is transferred from at least a portion of the hot air stream (77) to at least one gasifier (78) in such a way that at least a portion of the heat from the hot air stream is transferred to a steam stream and / or an oxygen stream in at least one heat transfer device to form a preheated steam stream and / or a hot oxygen stream that acts as an oxidant in the gasification reaction, and wherein at least a portion of the hot air stream and at least one gasifier are indirectly thermally coupled through the steam stream and / or the oxygen stream, or

[0117] b2) In the case where at least one gasifier is selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor, heat is transferred from at least a portion of the hot air flow (77) to at least one gasifier (78) via a heat transfer device (third aspect of the fourth embodiment). Figure 5 (not shown), wherein at least a portion of the heat from the hot air stream is then transferred to the feed stream via a heat transfer device to form a preheated feed stream, and wherein at least a portion of the hot air stream is indirectly thermally coupled to at least one gasifier.

[0118] When at least one gasifier (78) is selected from the group consisting of a countercurrent fixed-bed reactor, a co-current fixed-bed reactor, a bubbling fluidized-bed reactor, and a circulating fluidized-bed reactor (e.g., having at least one burner), at least a portion of the hot air stream (77) can be added to at least one gasifier (78). Other suitable means for adding the hot air stream to such a gasifier are known in the art and can be selected accordingly.

[0119] In a second aspect of the fourth embodiment of the invention, a clinker-raw meal mixture (71) enters at least one cement kiln (72), and hot clinker (73) exits the at least one cement kiln (72) in a downstream direction. Next, the hot clinker (73) enters a clinker cooler (74) downstream of and fluidly connected to the at least one cement kiln (72). The hot clinker (73) is cooled by an airflow (76) in the clinker cooler (74). The cooled clinker (75) exits the clinker cooler (74) in a downstream direction. A hot airflow (77) also exits the clinker cooler (74) and is incorporated into at least one heat transfer device fluidly connected to the clinker cooler (74). Figure 5 (Not shown in the image) Steam flow and / or oxygen flow ( Figure 5 (Not shown) also enters at least one heat transfer device. Heat is transferred within at least one heat transfer device from at least a portion of the hot air stream (77) to the steam stream and / or oxygen stream. The cold air stream ( Figure 5 (not shown in the image) and preheated steam stream and / or hot oxygen stream ( Figure 5 (Not shown) The pretreated steam and / or hot oxygen streams exit at least one heat transfer device through a cold air outlet and a preheated steam and / or hot oxygen outlet, respectively. The pretreated steam and / or hot oxygen streams then enter at least one gasifier (78) downstream of and fluidly connected to the preheated steam and / or hot oxygen outlets. The preheated steam and / or hot oxygen streams act as oxidants for the gasification reaction within the at least one gasifier (78). A first feed stream (79) enters at least one gasifier (78) and is converted into a crude synthesis gas stream (80) in the gasification reaction using the preheated steam and / or hot oxygen stream, which exits at least one gasifier (78) in a downstream direction. The crude synthesis gas stream (80) optionally contains halogens.

[0120] In this second aspect of the first invention, at least one gasifier (78) is preferably selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor.

[0121] Preferably, the steam stream is heated in at least one heat transfer device by at least a portion of the hot air stream (77), and then enters at least one gasifier (78) as a preheated steam stream. More preferably, the oxygen stream is heated in at least one heat transfer device by at least a portion of the hot air stream (77), and then enters at least one gasifier (78) as a hot oxygen stream. Most preferably, heat is transferred from at least a portion of the hot air stream to the steam stream in a first heat transfer device, and then heat is transferred from at least a portion of the hot air stream to the oxygen stream in a second heat transfer device.

[0122] At least one heat transfer device is preferably a heat exchanger suitable for transferring heat from a first gaseous flow to a second gaseous flow. More preferably, the heat transfer device is selected from the group consisting of: shell-and-tube heat exchangers, tube-and-shell heat exchangers, plate heat exchangers, plate-fin heat exchangers, microchannel heat exchangers, and waste heat recovery units. Suitable flow arrangements include countercurrent flow, crossflow, etc.

[0123] In cases where heat is transferred from at least a portion of the hot air stream to the oxygen stream and the steam stream, it is preferable that the heat is transferred from at least a portion of the hot air stream to the steam stream in a first heat exchange device, and then the heat is transferred from at least a portion of the hot air stream to the oxygen stream in a second heat transfer device. More preferably, the first heat transfer device is a heat exchanger suitable for transferring heat from a first gaseous stream to a second gaseous stream, and the second heat transfer device is a heat exchanger suitable for transferring heat from the first gaseous stream to the second gaseous stream. Most preferably, the first heat transfer device is selected from the group consisting of: shell-and-tube heat exchangers, shell-and-tube heat exchangers, plate heat exchangers, plate-fin heat exchangers, microchannel heat exchangers, and waste heat recovery units. Most preferably, the second heat transfer device is selected from the group consisting of: shell-and-tube heat exchangers, shell-and-tube heat exchangers, plate heat exchangers, plate-fin heat exchangers, microchannel heat exchangers, and waste heat recovery units. Suitable flow arrangements for the first and second heat transfer devices include counter-current flow, cross-flow, etc.

[0124] In a third aspect of the fourth embodiment of the invention, a clinker-raw meal mixture (71) enters at least one cement kiln (72), and hot clinker (73) exits the at least one cement kiln (72) in a downstream direction. Next, the hot clinker (73) enters a clinker cooler (74) downstream of and fluidly connected to the at least one cement kiln (72). The hot clinker (73) is cooled by an airflow (76) in the clinker cooler (74). The cooled clinker (75) exits the clinker cooler (74) in a downstream direction. A hot airflow (77) also exits the clinker cooler (74) and is incorporated into a heat transfer device fluidly connected to the clinker cooler (74). Figure 5 (Not shown in the image) In the first raw material stream ( Figure 5 (Not shown) also enters the heat transfer device. Heat is transferred within the heat transfer device from at least a portion of the hot air stream (77) to the first feed stream. The cold air stream and the preheated first feed stream exit the heat transfer device through the cold air stream outlet and the preheated first feed stream outlet, respectively. The preheated first feed stream then enters at least one gasifier (78) downstream of and fluidly connected to the preheated first feed stream outlet, and is converted into a crude synthesis gas stream (80) in the gasification reaction by an oxygen stream (optionally together with a steam stream as an oxidant), which exits the at least one gasifier (78) in a downstream direction.

[0125] In this third aspect of the fourth embodiment, at least one gasifier (78) is preferably selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor.

[0126] The heat transfer device is preferably a heat exchanger suitable for transferring heat from a gaseous flow (at least a portion of the hot air flow (77)) to a solid and / or liquid first feedstock flow. Suitable heat exchangers include direct contact heat exchangers, plate heat exchangers, tubular heat exchangers, etc. Suitable heat exchangers for transferring heat from a gaseous flow (at least a portion of the hot air flow (77)) to a solid and / or liquid first feedstock are known in the art and can be selected accordingly. Suitable flow arrangements include countercurrent flow, crossflow, etc.

[0127] The cement plant according to the first aspect of the fourth embodiment, the second aspect of the fourth embodiment, and the third embodiment of the fourth embodiment further includes at least one pyrolysis reactor (81) having an inlet for a second feedstock (82), a first outlet for a condensable pyrolysis product stream (84) (“pyrolysis oil”), a second outlet for a non-condensable pyrolysis product stream (83) (“pyrolysis gas”), and a third outlet for solid and highly viscous byproducts of the pyrolysis reaction. Figure 5 (Not shown in the image). The non-condensable pyrolysis stream (83) contains methane, ethane, propane, H2, and CO2. At least one cement kiln (72) is downstream of and fluidly connected to a second outlet for the non-condensable pyrolysis product stream (83). The non-condensable pyrolysis product stream (83) exits at least one pyrolysis reactor (81) through the second outlet for the non-condensable pyrolysis product stream (83) and enters at least one cement kiln (72), whereby the non-condensable pyrolysis product stream (83) is used as supplementary fuel to heat clinker within at least one cement kiln. Solid and highly viscous byproducts of the pyrolysis reaction may also optionally be used as supplementary fuel to heat clinker within at least one cement kiln.

[0128] The second raw material is preferably selected from mixed waste plastics and waste rubber, such as scrap tires. Other raw materials suitable for pyrolysis reactions can also be used as secondary raw materials.

[0129] Pyrolysis is the thermal decomposition or degradation of feedstocks (such as mixed waste plastics and tires) under inert conditions, resulting in gaseous, liquid, and solid char fractions. During pyrolysis, the feedstock is converted into a variety of chemical substances, including a) gases such as H2, C1-C4 alkanes, C2-C4 alkenes, acetylene, propyne, and 1-butyne; b) pyrolysis oils with boiling temperatures ranging from 25°C to 500°C; and c) char. Pyrolysis methods are known in themselves. They are described, for example, in EP 0713906 A1 and WO95 / 03375 A1.

[0130] A gaseous fraction containing methane, ethane, propane, H2, and CO2 can be used as supplemental fuel to heat clinker in at least one cement kiln. This gaseous fraction has a higher calorific value than other supplemental (“secondary” fuels” such as waste. A liquid fraction (i.e., pyrolysis oil with a boiling point in the range of 25°C to 500°C) can be used, for example, as feedstock for olefin production in steam crackers and / or syngas production in syngas plants. The pyrolysis oil can be transported in suitable containers, for example, by truck or rail, to another location for further processing. Solid and highly viscous byproducts of the pyrolysis reaction can also be used as supplemental fuel to heat clinker in at least one cement kiln.

[0131] Therefore, the cement plant further includes at least one pyrolysis reactor that produces pyrolysis oil and pyrolysis gas from a second raw material, and wherein the pyrolysis gas is used to heat at least one cement kiln.

[0132] The portion of the hot air stream (77) not used as combustion air serves as the heat source for the gasification reaction of the first feedstock in at least one gasifier. Furthermore, in cases where at least one gasifier is selected from the group consisting of a counter-current fixed-bed reactor, a co-current fixed-bed reactor, a bubbling fluidized-bed reactor, and a circulating fluidized-bed reactor, at least a portion of the hot air stream is also used as an oxidant in the gasification reaction; or at least a portion of the hot air stream is used to transfer heat to a steam stream and / or an oxygen stream to form a preheated steam stream and / or a hot oxygen stream, which is then fed into at least one gasifier; or at least a portion of the hot air stream is used to transfer heat to the first feedstock, which is then fed into at least one gasifier. Additionally, the non-condensable pyrolysis product stream (83) is used as supplementary fuel to heat clinker in at least one cement kiln.

[0133] Any combination of the first, second, third, and fourth embodiments of the present invention as described above is within the scope of the present invention.

[0134] For example, the components of the cement plant according to the first embodiment can be combined with a dehalogenation unit (third embodiment) and a pyrolysis reactor (fourth embodiment).

[0135] The hot clinker exits the cement kiln after passing through a pre-cooling zone at a temperature of approximately 1150°C to approximately 1350°C. The hot clinker then enters a clinker cooler, where it is cooled to approximately 80°C to approximately 200°C using an airflow. Suitable clinker cooler designs include tubular coolers, planetary coolers, satellite coolers, and grate coolers. The hot clinker is cooled in at least one clinker cooler using counter-current or cross-counter-current airflows. The high-temperature components of such clinker coolers are fitted with refractory materials. The hot clinker is brought into contact with the airflow within the clinker cooler. Heat from the hot clinker is transferred to the airflow, which exits the clinker cooler as hot air.

[0136] Most preferably, at least one clinker cooler is a grate cooler. In such a grate cooler, hot clinker is transported on a moving grate bed or a combination of a fixed grate bed and a moving grate bed. The grate cooler is suitable for higher hot clinker throughput and for selectively diverting the hot airflow formed within the clinker cooler during heat transfer from the hot clinker to the airflow for further utilization. The grate cooler requires more cooling air than combustion (i.e., as secondary combustion air and optionally as tertiary combustion air).

[0137] The first raw material is preferably a solid and / or liquid material or a mixture of materials comprising organic compounds and / or organic polymers. The organic compounds and / or organic polymers contain bio-derived carbon and / or fossil-derived carbon. The carbon is preferably derived from post-consumer waste (“recycled carbon”). The first raw material may further contain impurities, such as inorganic and metallic components. Preferably, the first raw material is a solid and / or liquid raw material and is selected from the group consisting of carbonaceous products from crude oil refining, such as extra-heavy crude oil, tar sands, bitumen, coke, biomass, waste, mixtures thereof, and mixtures thereof with fossil raw materials such as coal, oil, and natural gas.

[0138] The term "biomass" includes, but is not limited to, wood, wood pellets, wood chips, straw, lignocellulosic biomass, energy crops, and algae.

[0139] The term "waste" includes fossil-based waste, bio-based waste, and mixtures thereof. Examples of waste suitable as feedstock include agricultural / cultivation residues such as wood processing residues, waste wood, logging residues, switchgrass, discarded seed corn, corn stalks and other crop residues, municipal solid waste (MSW), textiles, industrial waste, sewage sludge, plastic waste, mixed plastic waste, end-of-life tires, packaging waste, and pulverized residues such as automotive pulverized residues and mixtures thereof.

[0140] Preferably, the raw materials are selected from the group consisting of: biomass, municipal solid waste (MSW), pulverized residues such as automotive pulverized residues, textiles, plastic waste, packaging waste, and mixtures thereof.

[0141] The selection of gasifier type and size depends on the physical and / or chemical properties of the feedstock, preferably selected from the group consisting of water content, ash content, elemental composition, particle size distribution, and calorific value. Furthermore, the selection of gasifier type and size also depends on the availability of the feedstock type and quantity, and the infrastructure for transporting the feedstock to the location where at least one gasifier is installed. The selection of gasifier type and size also depends on the pretreatment methods applied to the feedstock. An overview of gasifier types is provided, for example, in James G. Speight, Handbook of Gasification Technology, Scrivener Publishing and Wiley, 2020, Chapter 8.4.2, pages 259–262.

[0142] At least one gasifier is selected from the group consisting of: countercurrent fixed bed reactor, co-current fixed bed reactor, bubbling fluidized bed reactor, circulating fluidized bed reactor, bottom-out entrained flow reactor and top-out entrained flow reactor.

[0143] In the case of a cement plant according to the invention comprising two or more gasifiers, at least two gasifiers are selected from the group consisting of countercurrent fixed-bed reactors, cocurrent fixed-bed reactors, bubbling fluidized-bed reactors, circulating fluidized-bed reactors, bottom-exhaust entrained flow reactors, and top-exhaust entrained flow reactors, and preferably are installed in series, i.e., gasifier 2 is downstream of and fluidly connected to gasifier 1. The advantage of installing at least two gasifiers in this manner is a higher conversion rate of the feedstock and intermediate products of the gasification reaction to the desired syngas components H2 and CO. More preferably, the first gasifier and the second gasifier are preferably gasifiers of different types. Most preferably, the first gasifier (gasifier 1) is selected from the group consisting of countercurrent fixed-bed reactors, cocurrent fixed-bed reactors, bubbling fluidized-bed reactors, and circulating fluidized-bed reactors, and the second gasifier (gasifier 2) is a bottom-exhaust entrained flow reactor or a top-exhaust entrained flow reactor. In this case, the conversion rate of the feedstock and intermediate products of the gasification reaction to the desired syngas components H2 and CO is even higher. Furthermore, in this preferred installation, solid byproducts (such as sludge) are preferably carbon-free and can therefore be disposed of, for example, in a landfill without further treatment. The same limitations discussed above regarding the addition of hot air or hot oxygen to at least one gasifier also apply to this aspect of the invention.

[0144] When three gasifiers are connected to each other in this manner, all three gasifiers are preferably of different types. The advantage of such an installation (especially when different types of gasifiers are used) is that the desired yields of the syngas components H2 and CO are even higher.

[0145] At least one gasifier is preferably selected from the group consisting of a free countercurrent fixed bed reactor, a co-current fixed bed reactor, a bubbling fluidized bed reactor, and a circulating fluidized bed reactor, wherein at least a portion of the hot air stream is added to the at least one gasifier; or wherein the at least one gasifier is preferably selected from the group consisting of a free bottom-exhaust entrained flow reactor and a top-exhaust entrained flow reactor, and wherein the cement plant further includes means for transferring heat from at least a portion of the hot air stream to the oxygen stream and / or steam stream.

[0146] Gasification reactions in gasifiers typically occur at temperatures >500°C in the presence of substoichiometric amounts of an oxidant (such as oxygen, air, steam, supercritical water, or mixtures of the foregoing). Oxygen is the most common oxidant used for gasification due to its availability and low cost. If steam is used as the oxidant, the crude syngas has a higher initial H₂:CO molar ratio than when oxygen is used as the oxidant. For example, a typical molar ratio “typical air:oxygen required for total oxidation of the feedstock” ranges from 0.3 to <1.

[0147] The feedstock is converted in at least one gasifier to produce crude syngas, which is primarily composed of H2, CO, H2O, CO2, methane, other hydrocarbons, and impurities. The initial H2:CO molar ratio of the crude syngas exiting the gasifier ranges from about 0.1:1 to about 3:1, and depends on the type of solid and / or liquid feedstock used, the oxidant, and other applied reaction conditions (such as the temperature and / or residence time used for the gasification reaction). The most desirable components of the syngas are H2 and CO.

[0148] The following optional features of the present invention can be combined with any of the embodiments described above:

[0149] Optionally, the crude syngas obtained by gasification in at least one gasifier is purified in at least one syngas purification unit to obtain clean syngas. Other gaseous substances (such as HCl and H2S) are formed and / or separated from the crude syngas in at least one optional syngas purification unit. Impurities are removed from the crude syngas in at least one syngas purification unit, and clean syngas is produced from the crude syngas.

[0150] It is preferred to use clean syngas obtained from at least one optional syngas purification unit because when clean syngas is used instead of crude syngas obtained directly from the gasification reaction in at least one gasifier, the catalyst utilized in the continuous process steps has an improved lifetime and maintains its activity.

[0151] Typical impurities in the crude syngas obtained from the gasification reaction in at least one gasifier include chlorides, sulfur-containing organic compounds (such as sulfur dioxide), trace heavy metals (e.g., as corresponding salts), and particulate residues. Various chemical and / or physical methods for removing such impurities from the crude syngas, such as filtration, washing, hydrotreating, and absorption / adsorption, are known and can be selected and tailored according to the type and corresponding concentration of impurities in the crude syngas and the tolerance for such impurities in continuous process steps. Some selected methods for removing impurities from the crude syngas will be discussed in more detail. One or more of these methods can also be implemented in at least one optional syngas purification unit. The selection of such methods does not limit the scope of the invention. A portion of the impurities, as well as ash and / or sludge formed as byproducts in the gasification reaction, are removed from the syngas.

[0152] Fine particles can be removed from crude syngas via cyclone separators and / or filters; trace heavy metals and chlorides are removed by wet scrubbing, catalytic hydrolysis is used to convert sulfur-containing organic compounds into H2S, and acid gas removal is used to extract sulfur-containing gases such as H2S. Large and fine particles in the syngas can also be removed by quenching in a flue gas scrubbing unit.

[0153] Preferably, the cement plant further includes a syngas purification unit for producing clean syngas from crude syngas, the syngas purification unit being downstream of and fluidly connected to at least one gasifier.

[0154] Optionally, the cement plant includes an additional chemical synthesis unit selected from the group consisting of a methanation unit, a methanol synthesis unit, and a Fischer-Tropsch synthesis unit, said additional chemical synthesis unit being downstream of and fluidly connected to a syngas purification unit or an optional water-gas shift unit, said optional water-gas shift unit being downstream of and fluidly connected to the syngas purification unit and upstream of and fluidly connected to the optional chemical synthesis unit.

[0155] The clean syngas may undergo a water-gas shift reaction before being fed into an optional methanation unit, methanol unit, or Fischer-Tropsch unit. The water-gas shift reaction may be combined with gasification in at least one gasifier, and / or the water-gas shift reaction may be carried out in a separate water-gas shift unit downstream of and fluidly connected to at least one syngas purification unit.

[0156] Impurities are removed from the crude syngas, and the clean syngas, having a first H2:CO molar ratio, then optionally enters a methanation unit (preferably having a water-gas shift unit downstream of and fluidly connected to at least one syngas purification unit and upstream of and fluidly connected to the methanation unit) or a methanol synthesis unit (preferably having a water-gas shift unit downstream of and fluidly connected to at least one syngas purification unit and upstream of and fluidly connected to the methanol synthesis unit) or a Fischer-Tropsch synthesis unit (preferably having a water-gas shift unit downstream of and fluidly connected to at least one syngas purification unit and upstream of and fluidly connected to the Fischer-Tropsch synthesis unit), in which the clean syngas is converted into methane or methanol or Fischer-Tropsch hydrocarbons.

[0157] Methane is formed by a methanation reaction in a methanation unit. Optional methanation units are downstream of and fluidly connected to at least one gasifier, and / or at least one optional syngas purification unit or optional methanation unit is downstream of and fluidly connected to a water-gas shift unit.

[0158] In this case, preferably, the clean syngas having a first H2:CO molar ratio undergoes a water-gas shift reaction in at least one water-gas shift unit. This increases the H2 content in the clean syngas by reacting a portion of the CO in the clean syngas with water to form additional H2 (and CO2), thereby forming a second syngas having a second H2:CO molar ratio and exiting the at least one water-gas shift unit. The second syngas having the second H2:CO molar ratio has a higher H2 content than the clean syngas having the first H2:CO molar ratio. This step is referred to as the water-gas shift reaction and is represented by chemical reaction scheme (1):

[0159] CO + H2O → CO2 + H2(1)

[0160] The water-gas shift reaction will be carried out in a temperature range of about 200°C to about 480°C using a variety of catalysts (such as copper-zinc-aluminum catalysts and chromium or copper-promoted iron-based catalysts). The required water-gas shift reaction and the type of unit can be adapted to the general conditions of the method (e.g., the type of feedstock used for the gasification reaction and how much additional H2 is expected to be obtained by the chemical reaction scheme (1)).

[0161] The methanation reaction is described by chemical reaction schemes (2) and (3):

[0162] CO + 3H2 → CH4 + H2O(2)

[0163] CO2 + 4H2 → CH4 + 2H2O (3)

[0164] Methanation reactions and suitable methanation units are described, for example, in S. Rönsch, J. Schneider, S. Matthischke, M. Schlüter, M. Götz, J. Lefebvre, P. Prabhakaran, S. Bajohr: Review on methanation - From fundamentals to current projects; Fuel 166 (2016) 276-296, and can be selected and adapted by a technician.

[0165] The methanation reaction is a catalytic reaction, for example, using an alumina-supported nickel catalyst, preferably a honeycomb catalyst, at 1 bar to 70 bar and 200°C to 700°C, preferably 5 bar to 60 bar and 200°C to 700°C, more preferably 10 bar to 45 bar and 200°C to 550°C.

[0166] Clean syngas can be converted into methanol in an optional methanol synthesis unit. In this case, the clean syngas having a first H2:CO molar ratio preferably undergoes a water-gas shift reaction in at least one water-gas shift unit as described above before entering the methanol synthesis unit. Methanol is produced from the syngas in a low-pressure methanol process, for example in an adiabatic or quasi-isothermal reactor, by a catalytic gas-phase reaction using a catalyst at about 5 MPa to about 10 MPa and about 200°C to about 300°C. The clean syngas is provided by a syngas purification unit or by an optional water-gas shift unit in which the H2:CO molar ratio is changed for methanol synthesis. The catalyst is, for example, a mixture of copper and zinc oxides supported on alumina. Methanol synthesis suitable for combination with the production system according to the invention and various alternatives thereof are disclosed in Ullmann's Encyclopedia of Industrial Chemistry (2012), chapter “Methanol”, pages 3 to 12.

[0167] Clean syngas can be converted into hydrocarbons (“Fischer-Tropsch hydrocarbons”) such as light synthetic crude oil via an FT process in an optional Fischer-Tropsch (FT) reactor unit. In this case, the clean syngas having a first H2:CO molar ratio preferably undergoes a water-gas shift reaction in at least one water-gas shift unit as described above before entering the FT synthesis unit. The light synthetic oil can be further converted into naphtha, light olefins, or diesel fuel by hydrocracking and / or isomerization. For the production of gasoline and light olefins, the FT process operates at a temperature range of about 330°C to about 350°C and a pressure of about 2.5 MPa (high-temperature FT process); for the production of waxes and / or diesel fuels, the process operates at a temperature range of about 220°C to about 250°C and a pressure of about 2.5 MPa to about 4.4 MPa (low-temperature FT process). Suitable reactors for the low-temperature FT process include tubular fixed-bed reactors and slurry-bed reactors. Suitable reactors for the high-temperature FT process include circulating fluidized-bed reactors and SAS (Sasol Advanced Synthol) reactors. Iron-based and / or cobalt-based catalysts are used in the FT process. Suitable combinations of Fischer-Tropsch synthesis with the production system according to the invention and various alternatives thereof are disclosed in Ullmann's Encyclopedia of Industrial Chemistry (2012), chapter “Coal Liquefaction”, pages 20-33.

[0168] Therefore, the cement plant may optionally further include a syngas purification unit for obtaining clean syngas, the syngas purification unit being downstream of and fluidly connected to the gasifier; and optionally a methanation unit for obtaining methane from the clean syngas, the optional methanation unit being downstream of and fluidly connected to the syngas purification unit or an optional water-gas shift unit, the optional water-gas shift unit being downstream of and fluidly connected to the syngas purification unit.

[0169] The advantages of optionally converting syngas into methane are as follows:

[0170] The cement plants and methods according to the invention that produce syngas are typically installed in locations different from one or more (petrochemical) plants that require syngas as a feedstock to produce chemical products. Furthermore, the transportation of syngas over long distances is not feasible for safety reasons. The syngas produced by gasification is converted and continuously converted into methane, which is suitable for transport in a natural gas pipeline network to locations where syngas is required as a feedstock. There, the methane is converted back into syngas by, for example, methane steam reforming.

[0171] Optionally, the crude syngas obtained by the method can be at least partially dehalogenated by contacting it with a preheated mixture of raw and cooked feedstocks.

[0172] The first raw material is subjected to thermal pretreatment using at least a portion of a hot air stream, the thermal pretreatment being selected from the group consisting of drying and roasting.

[0173] Suitable drying methods include contacting at least a portion of the hot air stream with the first raw material via belt drying, fluidized bed drying, drum drying, spray drying, furnace drying, and rotary tray drying.

[0174] At least a portion of the hot air stream can be used to indirectly heat the first feedstock, preferably biomass, to a temperature in the range of about 200°C to about 320°C during the roasting pretreatment, so as to convert the first feedstock into char and thereby obtain a first feedstock with better fuel quality for gasification reaction.

[0175] Optionally, the crude syngas is cleaned in an optional syngas purification unit, and then, optionally, after a water-gas shift reaction, the clean syngas is converted into chemical products selected from the group consisting of methane, methanol, and Fischer-Tropsch hydrocarbons.

[0176] Optionally, a portion of the crude syngas is used to heat the cement kiln by burning the crude syngas in the method.

Claims

1. A cement plant, comprising: (i) At least one cement kiln, which is heated by burning at least one type of fuel and in which preheated raw clinker is formed into hot clinker. (ii) at least one clinker cooler, wherein the hot clinker transfers heat to an airflow to form a hot airflow. The clinker cooler is located downstream of and fluidly connected to at least one cement kiln. (iii) and at least one gasifier for producing crude syngas from a first feedstock by gasification, the crude syngas optionally containing halogens. At least a portion of the hot airflow formed in step (ii) is directly or indirectly thermally coupled to the at least one gasifier.

2. The cement plant according to claim 1, wherein, The at least one gasifier is selected from the group consisting of a counter-current fixed-bed reactor, a co-current fixed-bed reactor, a bubbling fluidized-bed reactor, and a circulating fluidized-bed reactor, wherein at least a portion of the hot air stream is added to the at least one gasifier, and wherein at least a portion of the hot air stream is directly thermally coupled to the at least one gasifier, or The at least one gasifier is selected from a group consisting of a bottom-flow entrained reactor and an top-flow entrained reactor, and the cement plant further includes at least one device for transferring heat from at least a portion of the hot air stream to a steam stream and / or an oxygen stream to form a preheated steam stream and / or a hot oxygen stream, and wherein at least a portion of the hot air stream is indirectly thermally coupled to the at least one gasifier, or The at least one gasifier is selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor, and the cement plant further includes means for transferring heat from at least a portion of the hot air stream to a first raw material stream to form a preheated first raw material stream, and the at least a portion of the hot air stream is indirectly thermally coupled to the at least one gasifier.

3. The cement plant according to any one of claims 1 and 2, wherein, The temperature range of the hot air stream formed in step (ii) is from about 700°C to about 1100°C.

4. The cement plant according to any one of claims 1 to 3, wherein, At least a portion of the crude syngas formed in the gasifier is used as fuel to heat the at least one cement kiln by burning the fuel.

5. The cement plant according to any one of claims 1 to 4, wherein, The crude syngas further contains halogens, and the cement plant further includes means for preheating the raw-clinker mixture and means for contacting the preheated raw-clinker mixture with the crude syngas, thereby transferring at least a portion of the halogens from the crude syngas to the pretreated clinker. The means for contacting the preheated raw-clinker mixture with the crude syngas has an inlet for the pretreated raw-clinker mixture and an outlet for the preheated raw-clinker mixture. The inlet for the preheated raw-clinker mixture is downstream of and fluidly connected to the means for preheating the raw-clinker mixture, and the at least one cement kiln is downstream of and fluidly connected to the outlet for the preheated raw-clinker mixture.

6. The cement plant according to any one of claims 1 to 5, wherein, The cement plant further includes at least one pyrolysis reactor that produces pyrolysis oil and pyrolysis gas from a second raw material, wherein the pyrolysis gas is used to heat the at least one cement kiln.

7. The cement plant according to any one of claims 1 to 6, wherein, At least one clinker cooler is a grate cooler.

8. The cement plant according to any one of claims 5 to 7, wherein, The preheated raw and cooked materials and the crude syngas are in countercurrent contact.

9. The cement plant according to any one of claims 1 to 8, wherein, The cement plant further includes a syngas purification unit for producing clean syngas from the crude syngas, the syngas purification unit being downstream of and fluidly connected to the at least one gasifier; and an additional chemical synthesis unit optionally selected from the group consisting of a methanation unit, a methanol synthesis unit, and a Fischer-Tropsch synthesis unit, the additional chemical synthesis unit being downstream of and fluidly connected to the syngas purification unit or an optional water-gas shift unit, the optional water-gas shift unit being downstream of and fluidly connected to the syngas purification unit and upstream of and fluidly connected to the optional chemical synthesis unit.

10. A method for gasifying a first feedstock in at least one gasifier, the method comprising the following steps (i) Provide a cement plant comprising at least one cement kiln, at least one clinker cooler, and at least one gasifier. (ii) Hot clinker is formed in at least one cement kiln. (iii) The hot clinker is cooled by an airflow in at least one clinker cooler, thereby forming a hot airflow. (iv) Transferring heat from at least a portion of the hot air stream to the at least one gasifier. (v) A crude syngas is formed in the at least one gasifier, the crude syngas optionally containing halogens.

11. The method according to claim 10, wherein, In step (iv) a) Introducing at least a portion of the hot air leaving the at least one clinker cooler into at least one gasifier, or b1) Transferring thermal energy from at least a portion of the hot air exiting the at least one clinker cooler to a steam stream and / or an oxygen stream, and then feeding the steam stream and / or oxygen stream into at least one gasifier, or b2) Transfer at least a portion of the hot air leaving the at least one clinker cooler to the first raw material, and then feed the first raw material into at least one gasifier.

12. The method according to any one of claims 10 and 11, wherein, The at least one gasifier is selected from the group consisting of the following: a) a countercurrent fixed-bed reactor, a co-current fixed-bed reactor, a bubbling fluidized-bed reactor, and a circulating fluidized-bed reactor, wherein at least a portion of the hot air stream is added to the at least one gasifier, and wherein at least a portion of the hot air stream is directly thermally coupled to the at least one gasifier, or b1) wherein the at least one gasifier is selected from the group consisting of a bottom-flow entrained reactor and an top-flow entrained reactor, and wherein the cement plant further includes at least one means for transferring heat from at least a portion of the hot air stream to the steam stream and / or oxygen stream to form a preheated steam stream and / or hot oxygen stream, and wherein at least a portion of the hot air stream is indirectly thermally coupled to the at least one gasifier, or b2) wherein the at least one gasifier is selected from the group consisting of a bottom-flow entrained flow reactor and an top-flow entrained flow reactor, and wherein the cement plant further includes means for transferring heat from at least a portion of the hot air stream to the first raw material stream to form a preheated first raw material stream, and wherein at least a portion of the hot air stream is indirectly thermally coupled to the at least one gasifier.

13. The method according to any one of claims 10 and 12, wherein, The temperature range of the hot air stream formed in step (ii) is from about 700°C to about 1100°C.

14. The method according to any one of claims 10 to 13, wherein, The crude syngas is at least partially dehalogenated by contacting it with the preheated raw-cooked mixture.

15. The method according to any one of claims 10 to 14, wherein, The crude syngas is cleaned in an optional syngas purification unit, and then, optionally, after a water-gas shift reaction, the cleaned syngas is converted into chemical products selected from the group consisting of methane, methanol, and Fischer-Tropsch hydrocarbons.

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