Flue gas treatment apparatus and associated methods

Abstract

A treatment plant of hot flue gases emitted by an industrial plant, the treatment plant comprising a gas circuit and having a first heat exchange chamber along a first branch and a second heat exchange chamber along a second branch, a temperature measuring device and / or a flow measuring device of the flue gases, an adjustment member movable at least between a first position and a second position. In the first position, the flue gases are allowed to be conveyed into the first heat exchange chamber, while the flue gases are prevented or reduced from being conveyed into the second heat exchange chamber, and in the second position, the flue gases are allowed to be conveyed into both the first heat exchange chamber and the second heat exchange chamber. A control unit is configured to command the adjustment member to be in the first position or in the second position based on the temperature value and / or the flow value of the flue gases.

Description

Technical Field

[0001] This invention relates to equipment for treating flue gas emitted from industrial plants, specifically metal processing or casting plants for ferrous and non-ferrous metals, wherein at least a portion of the thermal energy of the flue gas is recovered for reuse. The treatment equipment of this invention relates to eliminating or at least reducing one or more types of pollutants included in the flue gas. This invention also relates to a corresponding flue gas treatment method. Background Technology

[0002] In industrial processes involving high-temperature thermal processes, particularly when raw materials are contaminated with polymer elements, high concentrations of pollutants can be found in flue gas. This occurs, for example, in municipal solid waste treatment plants, waste-to-energy plants, or steel mills that recycle scrap metal, especially where ferrous metal scrap is melted in furnaces, such as electric arc furnaces. The materials introduced into these industrial processes (municipal waste in waste-to-energy plants, scrap metal in electric arc furnaces) inevitably contain polymer pollutants, which, due to the high temperatures and subsequent cooling, can generate dioxins and furans. Dioxins and furans carried by industrial process exhaust gases, if released into the atmosphere, can pose a threat to human health.

[0003] In the recycling of metal scrap, particularly ferrous metal scrap—which is often contaminated with polymeric substances such as paints, coatings, or plastics—electric arc furnaces (EAFs) are commonly used. Polymers are readily combustible, and their byproducts ultimately enter the gas stream generated by the processing in the EAF. EAF processing typically involves very high temperatures, particularly above 1500°C, resulting in the presence of dioxin precursors in the flue gas. Furthermore, EAF processing is characterized by a high degree of discontinuity due to the material loading operation, the melting process, and the subsequent casting of molten metal into the EAF: this leads to variations in the flow rate of the flue gas to be processed during batch-type processing steps. Finally, the exhaust gas from EAF processing is very high, necessitating energy recovery for further use.

[0004] Known methods for reducing pollutants in flue gas include maintaining the gases at temperatures above 700°C to 800°C, particularly above 850°C, for more than 2 seconds, followed by rapid cooling between 600°C and 250°C, preferably at a rate above 200°C / second to 300°C / second. Activated carbon injection can also be provided to reduce pollutants.

[0005] Rapid cooling of flue gas can be achieved using a quenching tower, in which a mixture of air and water is injected into the flue gas stream at ambient pressure and temperature. These gases, in close contact with the injected mixture, release the heat required for the liquid portion of the mixture to evaporate and cool down within the tower's volume. The tower is designed such that the velocity of the flue gas stream—combined with the velocity of the injected water stream—allows for the desired cooling rate of the flue gas. However, a drawback associated with quenching towers is that the process does not allow for the recovery, at least partially, of the heat energy present in the flue gas: in effect, the vapors produced by the process disperse into the atmosphere.

[0006] Systems that recover heat energy from industrial processes are known as “waste heat boilers” (WHBs), in which a working fluid flows within multiple tubes defining a heat exchanger to receive heat energy from flue gas: these tubes are fluidly connected to a steam tank that receives the gaseous working fluid. The circulation of the working fluid is determined by heat itself, causing the gaseous working fluid to flow toward the steam tank, and the liquid working fluid to flow from the steam tank toward the heat exchanger to remove heat from the flue gas of the industrial plant: in this type of WHB, the fluid circulation is called “natural circulation” to specify that no pump is involved in inducing the fluid flow (it can also be in auxiliary or forced circulation, in which at least one pump is installed for the circulation of the working fluid). However, since the flow rate of the working fluid depends on the heat energy exchanged with the flue gas, which is generated in a non-constant amount as is typically the case in EAF processes, it is impossible to achieve a sufficient flue gas cooling rate when the flow rate varies. The resulting flue gas cooling rate, beyond the parameters mentioned above, leads to the reorganization of dioxins and furans dispersed in the atmosphere through new synthesis.

[0007] In summary, the applicant points out that the two aforementioned technologies, namely the rapid quenching tower technology and the waste heat boiler technology, have significant drawbacks when it is necessary to combine the reduction of pollutants in flue gas with heat recovery.

[0008] Scope of Invention

[0009] Therefore, the scope of the present invention is to at least partially solve one or more of the disadvantages and / or limitations of the prior solutions.

[0010] The first scope is to provide flue gas treatment equipment and related methods that are capable of reducing one or more pollutants, particularly dioxins and furans, contained in flue gas emitted from industrial plants involving combustion or high-temperature processes.

[0011] Another scope is to provide flue gas treatment equipment and related methods that are capable of recovering, at least partially recovering, the thermal energy contained in the flue gas for further use.

[0012] Another area is providing flue gas treatment equipment and related methods that can combine energy recovery and reduction of pollutants in flue gas.

[0013] Another area is providing flue gas treatment equipment and related methods that can improve the control of flue gas cooling rates during pollutant treatment processes.

[0014] Another area is providing reliable and effective flue gas treatment equipment and related methods that reduce pollutants and are highly efficient in terms of energy recovery.

[0015] These ranges, and the many more ranges that will appear more frequently in the following description, are generally achieved by the flue gas treatment apparatus and related methods described in accordance with one or more of the appended claims and / or one or more of the following aspects. Summary of the Invention

[0016] The first aspect relates to a treatment apparatus (1) for hot flue gas discharged from an industrial plant, the treatment apparatus (1) comprising a gas circuit and a fluid circuit, the gas circuit comprising:

[0017] - At least a first heat exchange chamber (11) and a second heat exchange chamber (12), both the first heat exchange chamber (11) and the second heat exchange chamber (12) including corresponding gas inlets (11a, 12a) and gas outlets (11b, 12b), the first heat exchange chamber (11) and the second heat exchange chamber (12) being configured to receive the flue gas in the inlet;

[0018] - First flue gas supply pipe (23) and second flue gas supply pipe (24), the first flue gas supply pipe (23) and the second flue gas supply pipe (24) respectively connect the inlet (11a) of the first heat exchange chamber (11) and the inlet (12a) of the second heat exchange chamber (12) to the flue gas source (20);

[0019] - A first flue gas exhaust duct (25) and a second flue gas exhaust duct (26), the first flue gas exhaust duct (25) and the second flue gas exhaust duct (26) being connected to the outlet (11b) of the first heat exchange chamber (11) and the outlet (12b) of the second heat exchange chamber (12), respectively, and the first flue gas exhaust duct (25) and the second flue gas exhaust duct (26) being configured to transport flue gas away from the first heat exchange chamber (11) and the second heat exchange chamber (12),

[0020] The first flue gas supply pipe (23), the first flue gas discharge pipe (25) and the first heat exchange chamber (11) define the first branch of the gas circuit, while the second flue gas supply pipe (24), the second flue gas discharge pipe (26) and the second heat exchange chamber (12) define the second branch of the gas circuit.

[0021] - At least one of the temperature measuring device (50, 50a, 51, 51a) and the flow measuring device (60, 61), wherein the temperature measuring device (50, 50a, 51, 51a) and the flow measuring device (60, 61) are configured to provide a representative signal of the temperature of the flue gas and a representative signal of the flow rate, respectively.

[0022] - At least one adjusting member (40, 41), said at least one adjusting member (40, 41) being movable between at least two of the following:

[0023] In the first position, flue gas is allowed to be transported from the flue gas source (20) to the first heat exchange chamber (11), while preventing or reducing the transport of flue gas from the flue gas source (20) to the second heat exchange chamber (12), and

[0024] O Second position, in which flue gas is allowed to be transported from flue gas source (20) to both the first heat exchange chamber (11) and the second heat exchange chamber (12);

[0025] The fluid circuit is configured to transport working fluids, particularly water, in both liquid and gas phases, and the fluid circuit includes:

[0026] - At least a first heat exchange unit (101) and a second heat exchange unit (103), the first heat exchange unit (101) and the second heat exchange unit (103) being arranged in or in thermal contact with the first heat exchange chamber (11) and the second heat exchange chamber (12), respectively, and configured to allow heat exchange between flue gas and working fluid;

[0027] - A steam tank (110) is at least fluidly connected, optionally fluidly connected via natural circulation and / or auxiliary and / or forced circulation, to a first heat exchange unit (101) and a second heat exchange unit (103);

[0028] The processing device (1) further includes a control unit (200), which is configured to:

[0029] - Receive at least one of the representative signals of flue gas temperature and flow rate;

[0030] - Determine at least one of the representative temperature value and the representative flow rate value based on the corresponding representative signal;

[0031] - Determine at least one reference parameter based on at least one of the flue gas temperature or flow rate values;

[0032] - Defines the comparison between the reference parameter and at least one threshold;

[0033] Based on the comparison, the at least one adjusting member (40, 41) is commanded to be in a first position or in a second position.

[0034] The second aspect relates to a method for treating hot flue gas discharged from an industrial plant, the method being performed by a treatment apparatus optionally according to any of the aspects, the apparatus comprising a gas circuit and a fluid circuit, the gas circuit comprising:

[0035] - At least a first heat exchange chamber (11) and a second heat exchange chamber (12), both the first heat exchange chamber (11) and the second heat exchange chamber (12) including corresponding gas inlets (11a, 12a) and gas outlets (11b, 12b), the first heat exchange chamber (11) and the second heat exchange chamber (12) being configured to receive the flue gas in the inlet;

[0036] - First flue gas supply pipe (23) and second flue gas supply pipe (24), the first flue gas supply pipe (23) and the second flue gas supply pipe (24) respectively connect the inlet (11a) of the first heat exchange chamber (11) and the inlet (12a) of the second heat exchange chamber (12) to the flue gas source (20);

[0037] - A first flue gas exhaust duct (25) and a second flue gas exhaust duct (26), the first flue gas exhaust duct (25) and the second flue gas exhaust duct (26) being connected to the outlet (11b) of the first heat exchange chamber (11) and the outlet (12b) of the second heat exchange chamber (12), respectively, and the first flue gas exhaust duct (25) and the second flue gas exhaust duct (26) being configured to transport flue gas away from the first heat exchange chamber (11) and the second heat exchange chamber (12),

[0038] The first flue gas supply pipe (23), the first flue gas discharge pipe (25) and the first heat exchange chamber (11) define the first branch of the gas circuit, while the second flue gas supply pipe (24), the second flue gas discharge pipe (26) and the second heat exchange chamber (12) define the second branch of the gas circuit.

[0039] - At least one of the temperature measuring device (50, 50a, 51, 51a) and the flow measuring device (60, 61), wherein the temperature measuring device (50, 50a, 51, 51a) and the flow measuring device (60, 61) are configured to provide a representative signal of the temperature of the flue gas and a representative signal of the flow rate, respectively.

[0040] - At least one adjusting member (40, 41), said at least one adjusting member (40, 41) being movable between at least two of the following:

[0041] In the first position, flue gas is allowed to be transported from the flue gas source (20) to the first heat exchange chamber (11), while preventing or reducing the transport of flue gas from the flue gas source (20) to the second heat exchange chamber (12), and

[0042] O Second position, in which flue gas is allowed to be transported from flue gas source (20) to both the first heat exchange chamber (11) and the second heat exchange chamber (12);

[0043] The fluid circuit is configured to transport working fluids, particularly water, in both liquid and gas phases, and the fluid circuit includes:

[0044] - At least a first heat exchange unit (101) and a second heat exchange unit (103), the first heat exchange unit (101) and the second heat exchange unit (103) being arranged in or in thermal contact with the first heat exchange chamber (11) and the second heat exchange chamber (12), respectively, and configured to allow heat exchange between flue gas and working fluid;

[0045] - A steam tank (110) that is at least fluidly connected to a first heat exchange unit (101) and a second heat exchange unit (103);

[0046] The method includes at least the following steps performed by the processing device (1):

[0047] - Receive at least one of the representative signals of flue gas temperature and flow rate;

[0048] - Determine at least one of the representative temperature value and the representative flow rate value based on the corresponding representative signal;

[0049] - Determine at least one reference parameter based on at least one of the flue gas temperature or flow rate values;

[0050] - Defines the comparison between the reference parameter and at least one threshold;

[0051] Based on the comparison, the at least one adjusting member (40, 41) is commanded to be in a first position or in a second position.

[0052] In the third aspect according to any of the foregoing aspects, the gas circuit includes temperature measuring devices (50, 50a, 51, 51a), which include a first high-temperature sensor (50, 51) disposed upstream of the first heat exchange chamber (11).

[0053] In the fourth aspect according to any of the foregoing aspects, the gas circuit includes temperature measuring devices (50, 50a, 51, 51a), which include a second high-temperature sensor (51) arranged upstream of the second heat exchange chamber (12).

[0054] In the fifth aspect according to any of the foregoing aspects, the gas circuit includes temperature measuring devices (50, 50a, 51, 51a), the temperature measuring devices (50, 50a, 51, 51a) including at least one cryogenic sensor (50a, 51a) disposed downstream of the first heat exchange chamber (11) and / or the second heat exchange chamber (12).

[0055] In the sixth aspect according to any of the foregoing aspects, the gas circuit includes a first high-temperature sensor (50) located upstream of the first heat exchange chamber (11) and specifically arranged on the first flue gas supply duct (23).

[0056] In the seventh aspect according to any of the foregoing aspects, the gas circuit includes a second high-temperature sensor (51), which is specifically separate from and different from the first high-temperature sensor (50) and is arranged upstream of the second heat exchange chamber (12) on the second flue gas supply duct (24).

[0057] In the eighth aspect according to any of the foregoing aspects, the gas circuit includes a first cryogenic sensor (50a) disposed downstream of the first heat exchange chamber (11) on the first flue gas exhaust duct (25).

[0058] In the ninth aspect according to any of the foregoing aspects, the gas circuit includes a second cryogenic sensor (51a) disposed downstream of the second heat exchange chamber (12) on the second flue gas exhaust duct (26).

[0059] In the 10th aspect according to any of the foregoing aspects, the control unit is configured to determine the temperature change parameter as the difference between a temperature value measured by at least one high-temperature sensor (50, 51) and a temperature value measured by at least one low-temperature sensor (50a, 51a), the reference parameter being based on the temperature change parameter.

[0060] In the 11th aspect according to any of the foregoing aspects, the control unit is configured to determine a first temperature change parameter, which represents the temperature change of the flue gas, particularly between the upstream and downstream sections of the first heat exchange chamber (11).

[0061] In the 12th aspect according to any of the foregoing aspects, the control unit is configured to determine a second temperature change parameter that represents the temperature change of the flue gas, particularly between the upstream and downstream sections of the second heat exchange chamber (12).

[0062] In the 13th aspect according to any of the foregoing aspects, the reference parameter is based on a first temperature change parameter or a second temperature change parameter or a combination of the first temperature change parameter and the second temperature change parameter.

[0063] In the 14th aspect according to any of the foregoing aspects, the control unit is configured to:

[0064] - Compare the first temperature change parameter and / or the second temperature change parameter, or optionally a combination thereof, with the corresponding temperature change threshold;

[0065] - If the temperature change parameter is lower than the corresponding temperature change threshold, then command at least one adjusting member (40, 41) to be in the first position; or

[0066] Optionally, if the temperature change exceeds the corresponding temperature change threshold, then the at least one adjusting member (40, 41) is commanded to be in the second position.

[0067] Specifically, the temperature change threshold includes a range between 200°C and 600°C, particularly between 300°C and 500°C, and more particularly between 350°C and 450°C.

[0068] In the 15th aspect according to any of the foregoing aspects, the control unit is configured to determine the upstream temperature value of the flue gas upstream of the first heat exchange chamber (11) and / or the second heat exchange chamber (12) by means of a high temperature sensor, and compare the upstream temperature value with an upstream temperature value threshold. In particular, the control unit is also configured to command the adjustment member based on the comparison.

[0069] In the 16th aspect of the foregoing, the control unit is configured to issue an alarm signal when the upstream temperature value is higher or lower than the upstream temperature value threshold.

[0070] In aspect 17 according to the two aforementioned aspects, the upstream temperature threshold includes a range between 550°C and 800°C, particularly between 600°C and 700°C, and particularly between 640°C and 660°C.

[0071] In the 18th aspect according to any of the foregoing aspects, the first heat exchange chamber (11) and the second heat exchange chamber (12) are configured to determine the cooling process of flue gas passing through the first heat exchange chamber and / or the second heat exchange chamber.

[0072] In another 18th aspect according to any of the foregoing aspects, the control unit (200) is configured to:

[0073] –Based on the flow rate and temperature variation parameters of the flue gas across the first heat exchange chamber (11) and / or the second heat exchange chamber (12), the cooling parameters representing the current flue gas cooling rate are determined;

[0074] - Compare the cooling parameters with a cooling rate threshold, which is set between 200°C / second and 400°C / second, for example, between 200°C / second and 250°C / second, or between 250°C / second and 300°C / second, or between 300°C / second and 350°C / second, or between 350°C / second and 400°C / second;

[0075] -If the cooling parameters are lower than the cooling rate threshold, the command adjustment component is placed in the first position;

[0076] - Optionally, if the cooling parameter is higher than the cooling rate threshold, the at least one adjusting member (40, 41) is commanded to be in the second position.

[0077] In the 19th aspect according to the foregoing, the reference parameter is based on the cooling rate parameter, and wherein the at least one threshold includes the cooling rate threshold.

[0078] In the 20th aspect according to any of the foregoing aspects, the cooling rate parameter is calculated according to the following formula:

[0079] in

[0080] in:

[0081] C 速率 [ΔC° / s] = Cooling parameter;

[0082] ΔT[°C] = Temperature change across the first heat exchange chamber (11) and / or the second heat exchange chamber (12), and in particular, the temperature change is calculated as the difference between the temperature measured by the high-temperature sensor and the temperature measured by the low-temperature sensor;

[0083] t pg [s] = the time it takes for gas particles to travel from the high-temperature sensor to the low-temperature sensor;

[0084] V c [m 3 = The control volume is defined as the gas volume, which includes the volume between the high-temperature sensor and the low-temperature sensor;

[0085] F g[m 3 / s] = the flow rate of the flue gas, specifically the flow rate of the flue gas is measured by the flow measurement device (60, 61).

[0086] In the 21st aspect according to any of the foregoing aspects, the reference parameter is based on both the temperature value and the flow rate value of the flue gas, particularly based on the temperature change parameter and the flow rate value, and more particularly based on the first temperature change parameter and / or the second temperature change parameter and the flow rate value.

[0087] In the 22nd aspect according to any of the foregoing aspects, the reference parameter is based on the temperature value of the flue gas upstream of the first heat exchange chamber (11) and the second heat exchange chamber (12).

[0088] In the 23rd aspect according to any of the foregoing aspects, the flow measurement devices (60, 61) are configured to provide a signal representing the total flow rate of flue gas emitted from the gas source (20), wherein, in particular, the sum of the flow rates of the flue gas flowing through the first heat exchange chamber (11) and the second heat exchange chamber (12) corresponds to the total flow rate, and the reference parameter is based on the total flow rate of the flue gas.

[0089] In the 24th aspect according to any of the foregoing aspects, the step of defining the reference parameters includes determining the flow rate of the flue gas, optionally the total flow rate, and the control unit is further configured to:

[0090] – Compare the traffic flow, optionally the total traffic flow, with the corresponding traffic threshold;

[0091] - If the flow rate is lower than the corresponding flow rate threshold, then command at least one regulating member (40, 41) to be in a first position; or

[0092] - Optionally, if the flow rate is higher than the corresponding flow rate threshold, the at least one regulating member (40, 41) is commanded to be in the second position.

[0093] In the 25th aspect according to any of the foregoing aspects, the flow measurement device includes at least a first flow sensor (60) and a second flow sensor (61), the first flow sensor (60) and the second flow sensor (61) being arranged on a first branch and a second branch of the gas circuit, respectively, and each flow sensor being configured to provide a signal representing the flow rate of flue gas entering the first branch and the second branch, respectively, and the control unit being configured to receive the representative signal of the flow rate and determine a first flow rate value and a second flow rate value of the flue gas with respect to the first branch and the second branch.

[0094] In the 26th aspect of the foregoing, the reference parameter is based on the first flow value and the second flow value, and optionally on a combination of the first flow value and the second flow value, and optionally on the difference between the flow in the first branch and the flow in the second branch.

[0095] In aspect 27 according to any of the foregoing aspects, the first flow sensor (60) and the second flow sensor (61) are respectively arranged on the following:

[0096] - First flue gas supply pipe (23) and second flue gas supply pipe (24), or

[0097] - First flue gas emission pipe (25) and second flue gas emission pipe (26).

[0098] In aspect 28 according to any of the foregoing aspects, the gas circuit includes a main flue gas supply duct (22) that connects the inlets (28) of the first flue gas supply duct (23) and the second flue gas supply duct (24) to the flue gas source (20), the main flue gas supply duct (22) being configured to deliver the flue gas discharged from the flue gas source (20), in particular the total amount of flue gas, toward both the first flue gas supply duct (23) and the second flue gas supply duct (24).

[0099] In aspect 29 according to any of the foregoing aspects, the flow measurement device includes an upstream flow sensor arranged on the main flue gas supply duct (22) and configured to provide a signal representing the flow rate of flue gas discharged from the gas source (20).

[0100] In the 30th aspect according to any of the foregoing aspects, the temperature measuring device includes an upstream temperature sensor arranged on the main flue gas supply duct (22) and configured to provide a signal representing the temperature of the flue gas discharged from the gas source (20).

[0101] In the 31st aspect according to any of the foregoing aspects, the outlet of the first flue gas discharge duct (25) and the outlet of the second flue gas discharge duct (26) converge into a main flue gas discharge duct (27), which is configured to transport the total amount of flue gas discharged from the flue gas source (20), wherein the flow measurement device includes a downstream flow sensor arranged on the main flue gas discharge duct (27) and configured to provide a signal representing the flow rate of the flue gas discharged from the gas source (20).

[0102] In the 32nd aspect according to any of the foregoing aspects, the at least one regulating member includes a first damper (40) arranged on a first branch of the gas circuit.

[0103] In the 33rd aspect according to any of the foregoing aspects, the at least one regulating member includes a second damper (41) arranged on a second branch of the gas circuit.

[0104] In the 34th aspect according to any of the foregoing aspects, the at least one regulating member includes a first booster (40) arranged on a first branch of the gas circuit, the booster specifically including a fan configured to promote or inhibit the flow of flue gas in the gas circuit, the booster including an electric motor configured to rotate the fan.

[0105] In the 35th aspect according to any of the foregoing aspects, the at least one regulating member includes a second booster (41) arranged on a second branch of the gas circuit, the booster specifically including a fan configured to promote or inhibit the flow of flue gas in the gas circuit, the booster including an electric motor configured to rotate the fan.

[0106] In aspect 36 according to any of the foregoing aspects, the first damper (40) and the second damper (41) are arranged on the following:

[0107] - First flue gas supply pipe (23) and second flue gas supply pipe (24), or

[0108] - First flue gas emission pipe (25) and second flue gas emission pipe (26).

[0109] In the 37th aspect according to any of the foregoing aspects, the steam tank (110) is configured to receive a gaseous working fluid from at least one of the first heat exchange unit (101) and the second heat exchange unit (103), and to deliver a liquid working fluid to at least one of the first heat exchange unit (101) and the second heat exchange unit (103).

[0110] In aspect 38, as described in any of the foregoing aspects:

[0111] - When the at least one regulating member (40, 41) is arranged in a first position, the steam tank (110) is configured to receive gaseous working fluid from the first heat exchange unit (101) and to deliver liquid working fluid to the first heat exchange unit (101); and

[0112] When the at least one regulating member (40, 41) is arranged in the second position, the steam tank (110) is configured to receive gaseous working fluid from both the first heat exchange unit (101) and the second heat exchange unit (103), and to deliver liquid working fluid to both the first heat exchange unit (101) and the second heat exchange unit (103).

[0113] In the 39th aspect according to any of the foregoing aspects, the heat exchange between the flue gas and the working fluid determines that the working fluid changes from a liquid phase to a gas phase, the change determines that the working fluid flows through a fluid loop, and wherein the change determines that the gas phase working fluid is transported from at least one of the first heat exchange unit (101) and the second heat exchange unit (103) toward the steam tank (110).

[0114] In the 40th aspect according to any of the foregoing aspects, wherein:

[0115] - When the at least one adjusting member (40, 41) is arranged in a first position, heat exchange occurs in the first heat exchange chamber (11), while heat exchange is prevented in the second heat exchange chamber (12); and

[0116] - When the at least one adjusting member (40, 41) is arranged in the second position, heat exchange occurs in both the first heat exchange chamber (11) and the second heat exchange chamber (12).

[0117] In aspect 41 according to any of the foregoing aspects, the steam tank (110) is arranged relative to the ground at a height higher than the corresponding heights of the first heat exchange unit (101) and the second heat exchange unit (103). Optionally, the steam tank (110) is arranged relative to the ground at a height higher than the corresponding heights of the first heat exchange chamber (11) and the second heat exchange chamber (12).

[0118] In the 42nd aspect according to any of the foregoing aspects, the fluid circuit includes a first delivery conduit (111) that fluidly connects the outlet of the first heat exchange unit (101) to the steam tank (110) and is configured to deliver the working fluid in a gaseous phase from the first heat exchange unit (101) to the steam tank (110).

[0119] In the 43rd aspect according to any of the foregoing aspects, the fluid circuit includes a first return conduit (112) that connects the inlet of the first heat exchange unit (101) to the steam tank (110) and is configured to deliver the working fluid in liquid phase from the steam tank (110) to the first heat exchange unit (101).

[0120] In the 44th aspect according to any of the foregoing aspects, the fluid circuit includes a second delivery conduit (113) that fluidly connects the outlet of the second heat exchange unit (103) to the steam tank (110) and is configured to deliver the working fluid in a gaseous phase from the second heat exchange unit (103) to the steam tank (110).

[0121] In the 45th aspect according to any of the foregoing aspects, the fluid circuit includes a second return conduit (114) that connects the inlet of the second heat exchange unit (103) to the steam tank (110) and is configured to deliver the working fluid in liquid phase from the steam tank (110) to the second heat exchange unit (103).

[0122] In the 46th aspect according to any of the foregoing aspects, the fluid circuit includes a working fluid source (70) and at least one fluid delivery conduit (73, 74) connecting the working fluid source (70) to a steam tank (110), the working fluid source (70) being configured to deliver working fluid to the steam tank (110).

[0123] In the 47th aspect according to any of the foregoing aspects, the gas circuit includes an auxiliary heat exchange chamber (120) having a gas inlet (120a) and a gas outlet (120b), and the fluid circuit includes an auxiliary heat exchange unit (102') arranged in or in thermal contact with the auxiliary heat exchange chamber (120). In particular, the auxiliary heat exchange chamber (120) is separate from and different from the first heat exchange chamber (11) and the second heat exchange chamber (12), and the auxiliary heat exchange chamber (120) is configured to preheat the working fluid from the fluid source (70) before entering the steam tank (110).

[0124] In aspect 48 of the foregoing, the auxiliary heat exchange unit (102') includes an inlet (102'a) and an outlet (102'b), the inlet (102'a) being fluidly connected to a fluid source (70) via a fluid delivery pipe (73), and the outlet (102'b) being fluidly connected to a fluid supply inlet of a steam tank (110).

[0125] In the 49th aspect according to any of the foregoing aspects, the fluid circuit includes a first auxiliary heat exchange unit (102) arranged in or in thermal contact with the first heat exchange chamber (11) and configured to heat the working fluid flowing from the working fluid source (70) toward the steam tank (110).

[0126] In the 50th aspect according to any of the foregoing aspects, the fluid circuit includes a second auxiliary heat exchange unit (104) arranged in or in thermal contact with the second heat exchange chamber (12) and configured to heat the working fluid flowing from the working fluid source (70) toward the steam tank (110).

[0127] In aspect 51 according to any of the foregoing aspects, the first auxiliary heat exchange unit (102) includes an inlet fluidly connected to a fluid source (70) and an outlet fluidly connected to a fluid supply inlet of a steam tank (110).

[0128] In aspect 52 according to any of the foregoing aspects, the second auxiliary heat exchange unit (104) includes an inlet fluidly connected to a fluid source (70) and an outlet fluidly connected to a fluid supply inlet of a steam tank (110).

[0129] In aspect 53 according to any of the foregoing aspects, the first heat exchange chamber (11) and the second heat exchange chamber (12), and in particular the first heat exchange unit (101) and the second heat exchange unit (103), have different sizes to achieve different flow rates of flue gas and / or different heat exchange between flue gas and working fluid.

[0130] In the 54th aspect according to the foregoing, the first heat exchange unit (101) defines a first surface for heat exchange between flue gas and working fluid, and the second heat exchange unit (103) defines a second surface for heat exchange between flue gas and working fluid, the first surface being different from the second surface and particularly lower than the second surface.

[0131] In aspect 55 of the foregoing, the at least one adjusting member (40, 41) is movable in a third position, in which the transport of flue gas from the flue gas source (20) to the first heat exchange chamber (11) is prevented or reduced, while the transport of flue gas from the flue gas source (20) to the second heat exchange chamber (12) is permitted.

[0132] In the 56th aspect according to any of the foregoing aspects, the flow measurement device (60, 61) includes a differential pressure sensor or Pitot detector configured to provide a signal representing a differential pressure, and a control unit configured to determine the flow rate or velocity of flue gas flowing in the gas circuit based on the representative signal.

[0133] In aspect 57, as described in any of the foregoing aspects, the first heat exchange chamber (11) includes one or more, particularly two or more, first heat exchange units (101).

[0134] In aspect 58, as described in any of the foregoing aspects, the second heat exchange chamber (12) includes one or more, particularly two or more, second heat exchange units (103).

[0135] In aspect 59 according to any of the foregoing aspects, the gas circuit includes other heat exchange chambers configured to receive flue gas at an inlet, particularly a third or fourth heat exchange chamber, the other heat exchange chambers having corresponding inlets and outlets configured to receive and discharge flue gas, and the fluid circuit includes other heat exchange units respectively arranged in each of the other heat exchange chambers.

[0136] In the 60th aspect according to any of the foregoing aspects, the control unit is configured to determine the downstream temperature value of the flue gas downstream of the first heat exchange chamber (11) and / or the second heat exchange chamber (12) by means of a low temperature sensor, and compare the downstream temperature value with a downstream temperature value threshold. In particular, the control unit is also configured to command the adjustment member based on the comparison.

[0137] In aspect 61 of the foregoing, the downstream temperature threshold includes a range between 150°C and 350°C, particularly between 200°C and 300°C, more particularly between 230°C and 270°C, and more particularly approximately 250°C.

[0138] In aspect 62, as described in any of the foregoing aspects, the gas source (20) includes an electric arc furnace (EAF).

[0139] In aspect 63, as described in any of the foregoing aspects, the first branch of the flue gas circuit is arranged parallel to the second branch of the flue gas circuit.

[0140] In aspect 64 according to any of the foregoing aspects, the flue gas source (20) is configured to distribute the flue gas to the first heat exchange chamber (11) and / or the second heat exchange chamber (12).

[0141] In aspect 65 according to any of the foregoing aspects, the first heat exchange chamber (11) is directly connected to the flue gas source (20) via a first flue gas supply pipe (23), and the second heat exchange chamber (12) is directly connected to the flue gas source (20) via a second flue gas supply pipe (24), wherein the first supply pipe (23) and the second supply pipe (24) are different and discontinuous, and are specifically arranged to be parallel to each other.

[0142] Specifically, under at least one operating condition, the second heat exchange chamber (12) receives a large amount of flue gas that has not yet passed through the first heat exchange chamber (11).

[0143] In aspect 66 according to any of the foregoing aspects, the first flue gas supply duct (23) and the second flue gas supply duct (24) are parallel to each other according to the flue gas supply direction of the flue gas source (20).

[0144] In aspect 67, as described in any of the foregoing aspects, the first flue gas supply duct (23) and the second flue gas supply duct (24) are connected to each other based on the same flue gas source (20).

[0145] In aspect 68, as described in any of the foregoing aspects, the steam tank (110) is shared by the first heat exchange unit (101) and the second heat exchange unit (103).

[0146] In aspect 69 according to any of the foregoing aspects, the fluid circuit includes:

[0147] - A first delivery conduit (111) connected to the outlet of a first heat exchange unit (101) of a first heat exchange chamber (11), and configured to deliver the working fluid, particularly a gaseous working fluid, from the first heat exchange unit (101) to a steam tank (110); and

[0148] - A second delivery conduit (113) is connected to the outlet of the second heat exchange unit (103) of the second heat exchange chamber (12), and the second delivery conduit (113) is configured to deliver the working fluid, particularly the working fluid in the gas phase, from the second heat exchange unit (103) to the steam tank (110). Attached Figure Description

[0149] Some embodiments and aspects of the present invention will now be described with reference to the accompanying drawings, which are provided for illustrative purposes only. In the drawings:

[0150] - Figure 1 This is a schematic diagram of a processing device according to an embodiment of the present invention;

[0151] - Figure 2 This is a schematic diagram of a processing device according to another embodiment of the present invention.

[0152] definition

[0153] In this detailed description, corresponding parts illustrated in the various figures are indicated by the same reference numerals. The figures can be used to illustrate the invention by means of illustrations drawn to scale; therefore, the parts and components illustrated in the figures that are relevant to the purpose of the invention may be related only to schematic diagrams.

[0154] Upstream and / or downstream

[0155] The terms upstream and downstream refer to the direction or trajectory of fluid flowing within a fluid conduit configured for normal operation of the processing equipment. Specifically, in relation to gas circuits, upstream and downstream refer to the direction of gas flow from the gas source, i.e., the industrial plant, toward the outlet of the processing equipment. Detailed Implementation

[0156] Processing equipment and methods

[0157] Reference numeral 1 in the attached figure points to a treatment device for hot flue gas discharged from an industrial plant, which is implemented according to the first embodiment and the second embodiment respectively. Figure 1 and Figure 2 As shown, industrial plants, such as municipal solid waste treatment plants, waste-to-energy incineration plants, or electric arc furnaces (EAFs), melt scrap iron, particularly ferrous waste. The emitted hot flue gas typically contains several pollutants, such as dioxins and / or furans, which pose a threat to human health. The flue gas emitted from industrial plants is characterized by high temperatures, for example, between 800°C and 1600°C. This allows for at least partial recovery of thermal energy, but also, without adequate thermal and chemical treatment, can lead to the generation of the aforementioned pollutants.

[0158] Industrial plants are referred to as gas sources 20, such as Figure 1 and Figure 2 As shown, gas source 20 includes a furnace, such as an electric arc furnace (EAF): main flue gas supply duct 22 is configured to receive hot flue gas leaving the industrial plant and to convey the hot flue gas leaving the industrial plant toward the processing equipment to allow for gas processing and energy recovery. Main flue gas supply duct 22 is configured to convey a total flow rate of flue gas from gas source 20 toward the processing equipment.

[0159] The main flue gas supply duct 22 branches into a first flue gas supply duct 23 and a second flue gas supply duct 24 at branch point 28. The first flue gas supply duct 23 connects to the first heat exchange chamber 11, while the second flue gas supply duct 24 connects to the second heat exchange chamber 12. Therefore, flue gas can flow from the gas source 20 into the main flue gas supply duct 22, then separately into the first flue gas supply duct 23 and the second flue gas supply duct 24, and finally into the first chamber 11 and the second chamber 12. A settling chamber 30 can also be provided on the gas supply duct 22, in which—in a known manner—the flue gas velocity is reduced and the coarsest particles of dust in the suspension settle due to gravity and are collected at the bottom of the settling chamber 30. Depending on process requirements, air or oxygen can be injected to complete the combustion of gases such as CO and H2.

[0160] Each heat exchange chamber 11, 12 has corresponding inlets 11a, 12a fluidly connected to the first flue gas supply duct 23 and the second flue gas supply duct 24, and corresponding outlets 11b, 12b connected to the first flue gas exhaust duct 25 and the second flue gas exhaust duct 26, respectively. The first heat exchange chamber 11 and the second heat exchange chamber 12 internally define internal volumes for gas passages: according to one embodiment, the size of the first heat exchange chamber 11 is equal to the size of the second heat exchange chamber 12. Alternatively, according to another embodiment, the first heat exchange chamber and the second heat exchange chamber, and thus their corresponding internal volumes, can have different sizes: for example, the internal volume of the first heat exchange chamber 11 can be larger than the internal volume of the second heat exchange chamber 12.

[0161] according to Figure 1 and Figure 2 In the embodiment shown, the first flue gas emission duct 25 and the second flue gas emission duct 26 can converge at the convergence point 29 to form a common flue gas emission duct or a main flue gas emission duct 27, which is configured to transport the total amount of flue gas discharged from the flue gas source 20.

[0162] The combination of the first flue gas supply duct 23, the first flue gas exhaust duct 25, and the first heat exchange chamber 11 defines a first branch of the gas circuit. Similarly, the combination of the second flue gas supply duct 24, the second flue gas exhaust duct 26, and the second heat exchange chamber 12 defines a second branch of the gas circuit. Notably, the first and second branches are arranged in parallel and are fluidly connected to each other only through a branch point 28 and a convergence point 29. In other words, the flue gas flowing in the first branch is processed into the first heat exchange chamber 11, while the flue gas flowing in the second branch is processed into the second heat exchange chamber 12.

[0163] The gas circuit also includes at least one of temperature measuring devices 50, 50a, 51, 51a and flow measuring devices 60, 61, configured to provide representative signals of flue gas temperature and flow rate, respectively. The control unit 200 is set and configured to receive the corresponding representative signals and determine the temperature and / or flow rate values ​​of the flue gas.

[0164] More specifically, the temperature measuring device includes at least one high-temperature sensor 50, 51 disposed upstream of the first heat exchange chamber 11 and the second heat exchange chamber 12. The high-temperature sensor may be disposed upstream of the branch point 28 on the main flue gas supply duct 22: in this case, according to an alternative embodiment, the gas circuit may include a single high-temperature sensor. Alternatively, as... Figure 1 and Figure 2As shown in the embodiment, the high temperature sensor includes: a first high temperature sensor 50, which is arranged upstream of the first heat exchange chamber 11 on the first flue gas supply pipe 23; and a second high temperature sensor 51, which is separate from and different from the first high temperature sensor 50, and is arranged upstream of the second heat exchange chamber 12 on the second flue gas supply pipe 24.

[0165] The temperature measuring device may further include at least one cryogenic sensor 50a, 51a disposed downstream of the first heat exchange chamber 11 and the second heat exchange chamber 12. According to an embodiment not shown in the figures, the cryogenic sensor may be disposed downstream of the convergence point 29 on the main flue gas exhaust duct 27. Alternatively, according to... Figure 1 and Figure 2 In the embodiment shown, the temperature measuring device includes a first low-temperature sensor 50a disposed downstream of the first heat exchange chamber 11 on the first flue gas exhaust duct 25 and a second low-temperature sensor 51a disposed downstream of the second heat exchange chamber 12 on the second flue gas exhaust duct 26.

[0166] Based on the above, the control unit is configured to determine the temperature change parameter as the difference between the temperature values ​​measured by the high-temperature sensors 50, 51 and the low-temperature sensors 50a, 51a across the first heat exchange chamber 11 and / or the second heat exchange chamber 12. More specifically, the control unit is configured to determine the first temperature change parameter as the difference between the temperature value measured by the first high-temperature sensor 50 and the temperature value measured by the first low-temperature sensor 50a: in other words, the temperature change across the first heat exchange chamber 11 represents the cooling process of the flue gas flowing in the first branch.

[0167] Similarly, the control unit 200 is configured to determine the second temperature change parameter as the difference between the temperature value measured by the second high temperature sensor 51 and the temperature value measured by the second low temperature sensor 51a: the temperature change across the second heat exchange chamber 12 represents the cooling process of the flue gas flowing in the second branch.

[0168] The processing equipment also includes a flow measurement device, which in turn includes a first flow sensor 60 and a second flow sensor 61 respectively arranged on a first branch and a second branch of the gas circuit. Each flow sensor is configured to provide a signal representing the flow rate of flue gas entering the first branch and the second branch, respectively. The control unit is then configured to receive the representative flow rate signal and determine a first flow rate value and a second flow rate value for the flue gas in the first branch and the second branch. More specifically, the first flow sensor 60 and the second flow sensor 61 may be arranged on the first flue gas supply duct 23 and the second flue gas supply duct 24, or on the first flue gas exhaust duct 25 and the second flue gas exhaust duct 26, respectively. In other words, the flow sensors 60 and 61 may be arranged upstream or downstream of the heat exchange chamber; in any case, downstream arrangement is preferred for safety and reliability reasons due to the lower temperature involved.

[0169] The flow measurement devices 60 and 61 may include a differential pressure sensor or Pitot detector configured to provide a signal representing a pressure difference, and the control unit is then configured to determine the flow rate or velocity of flue gas flowing in the gas circuit based on the representative signal of the pressure difference.

[0170] The gas circuit also includes at least one regulating member 40, 41 movable at least between a first position and a second position. In the first position, flue gas is allowed to flow from the flue gas source 20 into the first heat exchange chamber 11, while preventing or reducing the flow of flue gas from the flue gas source 20 into the second heat exchange chamber 12; in the second position, flue gas is allowed to flow from the flue gas source 20 into both the first heat exchange chamber 11 and the second heat exchange chamber 12. In other words, the regulating member is configured to deflect the flue gas toward the first heat exchange chamber or alternatively toward both the first and second chambers. Therefore, when the regulating member is in the first position, the heat exchange surface between the flue gas and the working fluid is lower than the corresponding heat exchange surface when the regulating member is in the second position. This also determines that the amount of working fluid involved in the heat exchange with the flue gas when the regulating member is in the first position is lower than the amount of working fluid involved in the heat exchange with the flue gas when the regulating member is in the second position.

[0171] Furthermore, the regulating members 40 and 41 can also be moved in a third position, in which the transport of flue gas from the flue gas source 20 to the first heat exchange chamber 11 is prevented or reduced, while allowing the flue gas to be transported from the flue gas source 20 to the second heat exchange chamber 12. This last case is particularly advantageous when the sizes of the first and second heat exchange chambers are not the same: in fact, in this case, the amount of working fluid involved in heat exchange in the first heat exchange unit 101 is different from, for example, lower than, the amount of working fluid involved in the second heat exchange unit 103. When the first and second heat exchange chambers have different sizes, the control unit can command the regulating members to be in the first, second, and third positions according to the required heat exchange: in other words, the amount of working fluid involved in the cooling process varies between the first, second, and third positions of the regulating members, and therefore the exchanged heat energy (and therefore the cooling performance) also varies. Therefore, by commanding the regulating members to be in the first, second, and third positions, three different levels of energy exchange can be defined between the flue gas and the working fluid.

[0172] In one embodiment, the regulating component includes a first damper 40 and a second damper 41 respectively arranged on a first branch and a second branch of the gas circuit; these dampers are essentially baffles that either prevent or allow gas to pass through the first branch and / or the second branch. Partial opening of the dampers can result in regulation of the flue gas flow rate.

[0173] Alternatively, the regulating component includes a first booster 40 and a second booster 41 respectively arranged on a first branch and a second branch of the gas circuit, wherein the booster includes a fan configured to promote or inhibit the flow of flue gas within the gas circuit. The booster includes an electric motor connected to and commanded by the control unit, the electric motor being configured to rotate the fan; specifically, the control unit can change the angular velocity of the fan to regulate the flow of flue gas within the gas circuit.

[0174] The regulating component can be arranged upstream of heat exchange chambers 11 and 12 or alternatively downstream of them. Specifically, the regulating component can be arranged on both the first flue gas supply duct 23 and the second flue gas supply duct 24, or on the first flue gas exhaust duct 25 and the second flue gas exhaust duct 26, such as... Figure 1 and Figure 2 As shown in the diagram. Furthermore, regulating components can be arranged both upstream and downstream of heat exchange chambers 11 and 12.

[0175] The processing apparatus 1 also includes a fluid circuit configured to deliver a working fluid, such as water, in both liquid and gas phases to cause cooling of the flue gas as it passes through heat exchange chambers 11 and 12. The fluid circuit includes a working fluid source 70, at least one fluid delivery conduit 73 and 74, and a steam tank 110, wherein the fluid delivery conduit 73 and 74 fluidly connects the working fluid source 70 to the steam tank 110. The working fluid source 70 is configured to deliver the working fluid to the steam tank 110 via the fluid delivery conduit 77 and 74; pumps, i.e., electric pumps, may be provided on the fluid delivery conduit 77 and 74 to ensure the working fluid flows toward the steam tank.

[0176] The fluid circuit further includes at least a first heat exchange unit 101 and a second heat exchange unit 103, which are respectively arranged in or in thermal contact with the first heat exchange chamber 11 and the second heat exchange chamber 12, and are configured to allow heat exchange between the flue gas and the working fluid. The first heat exchange unit 101 includes at least one inlet 101a configured to receive the working fluid and at least one outlet 101b configured to deliver the working fluid: the inlet 101a of the first heat exchange unit 101 is fluidly connected to the outlet of the steam tank 110 via a first return pipe 112, while the outlet 101b of the first heat exchange unit 101 is fluidly connected to the inlet of the steam tank 110 via a first delivery pipe 111. Similarly, the second heat exchange unit 103 includes at least one inlet 103a configured to receive working fluid from the steam tank and at least one outlet 103b configured to deliver the working fluid to the steam tank: the inlet 103a of the second heat exchange unit 103 is fluidly connected to the outlet of the steam tank 110 via a second return pipe 114, while the outlet 103b of the second heat exchange unit 103 is fluidly connected to the inlet of the steam tank 110 via a second delivery pipe 113. It is noteworthy that the first heat exchange chamber 11 may include two or more first heat exchange units 101; similarly, the second heat exchange chamber 12 includes two or more second heat exchange units 103.

[0177] According to an embodiment, the first heat exchange unit 101 defines a first surface for heat exchange between flue gas and working fluid, and the second heat exchange unit 103 defines a second surface for heat exchange between flue gas and working fluid; the first surface may be different from the second surface. In this way, the heat exchanged in the first heat exchange chamber 11 will be different from the heat exchanged in the second heat exchange chamber 12.

[0178] Based on the above, the first heat exchange chamber 11 and the second heat exchange chamber 12, combined with the first heat exchange unit 101 and the second heat exchange unit 103, are configured to determine the heat exchange between the hot flue gas flowing in the gas loop and the working fluid flowing in the fluid loop. The heat exchange between the flue gas and the working fluid determines the state transition of the working fluid from the liquid phase to the gas phase: this transition determines the flow of the working fluid through the fluid loop; this is also referred to as natural circulation because no pump is provided to induce circulation of the working fluid within the fluid loop (in other embodiments, one or more pumps may be provided to obtain assisted or forced circulation). Specifically, this state transition determines the delivery of the gaseous working fluid from the first heat exchange unit 101 and / or the second heat exchange unit 103 toward the steam tank 110. Therefore, the steam tank 110 is configured to receive the gaseous working fluid through the first delivery conduit 111 and the second delivery conduit 113; the liquid working fluid then returns to the heat exchange units 101, 103 through the first return conduit 112 and the second return conduit 114.

[0179] More specifically, when the adjusting members 40 and 41 are arranged in the first position, heat exchange occurs in the first heat exchange chamber 11, while heat exchange is prevented in the second heat exchange chamber 12. Therefore, under these conditions, the working fluid flows in a gaseous state from the first heat exchange unit 101 to the steam tank 110, while no fluid flows from the second heat exchange unit 103 to the steam tank.

[0180] Conversely, when the adjusting members 40 and 41 are arranged in the second position, heat exchange occurs in both the first heat exchange chamber 11 and the second heat exchange chamber 12. Therefore, under this condition, the working fluid flows in a gaseous state from both the first heat exchange unit 101 and the second heat exchange unit 103 to the steam tank 110.

[0181] In one embodiment, the steam tank 110 is arranged at a height higher than the corresponding heights of the first heat exchange unit 101 and the second heat exchange unit 103 relative to the ground. More specifically, the steam tank 110 is arranged at a height higher than the corresponding heights of the first heat exchange chamber 11 and the second heat exchange chamber 12 relative to the ground to facilitate the delivery of gaseous working fluid from the heat exchange units to the steam tank 110.

[0182] The steam tank also includes a steam delivery conduit 130 configured to deliver a gaseous working fluid to an energy recovery device to at least partially recover the thermal energy contained in the steam. The energy recovery device may include a turbine for converting the pressure of the gaseous working fluid into mechanical or electrical energy. The energy recovery device is not described in detail in this document because its implementation is not essential to the purposes of this invention.

[0183] In a preferred embodiment, the fluid circuit includes at least one auxiliary heat exchange unit 102, 104, which is arranged in or in thermal contact with at least one of the first heat exchange chamber 11 and the second heat exchange chamber 12. The auxiliary heat exchange units 102, 104 are configured to heat the working fluid flowing from the working fluid source 70 toward the steam tank 110. In other words, the auxiliary heat exchange units 102, 104 ensure that the working fluid is preheated before entering the steam tank.

[0184] Specifically, the processing equipment may include a single auxiliary heat exchange unit 102 arranged in the first heat exchange chamber 11 or the second heat exchange chamber 12; alternatively, such as Figure 1 As shown, the processing equipment may include a first auxiliary heat exchange unit 102 and a second auxiliary heat exchange unit 104 respectively arranged in or in thermal contact with the first heat exchange chamber 11 and the second heat exchange chamber 12.

[0185] according to Figure 2 In the second embodiment shown, the fluid circuit may include an auxiliary heat exchange chamber 120 having a gas inlet 120a connected to the main flue gas exhaust duct 27 and a gas outlet 120b. The fluid circuit also includes an auxiliary heat exchange unit 102' disposed in or in thermal contact with the auxiliary heat exchange chamber 120, the auxiliary heat exchange unit 102' being configured to preheat the working fluid from the fluid source 70 before it enters the steam tank 110. Specifically, the inlet 102'a of the auxiliary heat exchange unit 102' is fluidly connected to the fluid source 70 via a fluid delivery pipe 73, and the outlet 102'b of the auxiliary heat exchange unit 102' is fluidly connected to the steam tank via another fluid delivery pipe 75. It is noteworthy that the auxiliary heat exchange chamber 120 and the auxiliary heat exchange unit 102' are distinct and separate from the first heat exchange chamber 11 and the second heat exchange chamber 12, as well as the first heat exchange unit 101 and the second heat exchange unit 103. According to the second embodiment, the auxiliary heat exchange chamber 120 is configured to receive flue gas in a first position, a second position, and an optional third position of the adjusting members 40, 41.

[0186] According to both the first and second embodiments, auxiliary heat exchange units 102, 104, 102' are arranged downstream of the first heat exchange unit 101 and the second heat exchange unit 103.

[0187] The control unit 200 of the processing equipment is configured to define a reference parameter based on at least one of the temperature or flow rate of the flue gas. For example, the reference parameter can be defined by the flow rate measured by a first or second flow sensor, or by the flow rate measured by a flow sensor arranged on the main flue gas supply duct 22 or the main flue gas discharge duct 27. Alternatively, the reference parameter can be determined by the temperature of the flue gas measured in the main flue gas supply duct 22 or in the first and / or second branches. Alternatively, the reference parameter can be based on a combination of the temperature measured by a temperature measuring device and the flow rate measured by a flow measuring device. Furthermore, in a specific embodiment, the reference parameter is based on a first temperature change parameter or a second temperature change parameter, or both of the first and second temperature change parameters, or a combination thereof. Additionally, the reference parameter is based on a combination of a first temperature change parameter and a flow rate measured in the first branch; similarly, the reference parameter can be based on a combination of a second temperature change parameter and a flow rate measured in the second branch. In another embodiment, the reference parameter can be based on a combination of a first and second temperature change parameter and a flow rate measured in the first and second branches.

[0188] The reference parameters can also be based on cooling parameters determined by the control unit, wherein the cooling parameters represent the current cooling rate of the flue gas based on the flow rate and temperature variation parameters of the flue gas flowing across the first heat exchange chamber 11 and / or the second heat exchange chamber 12. Specifically, the control unit 200 can be configured to calculate the cooling parameters according to the following formula:

[0189] in

[0190] in:

[0191] C 速率 [ΔC° / s] is the cooling parameter;

[0192] ΔT[°C] is the temperature change across the first heat exchange chamber 11 and / or the second heat exchange chamber 12. In particular, the temperature change is calculated as the difference between the temperatures measured by the high-temperature sensor and the low-temperature sensor of the first branch and / or the second branch.

[0193] t pg [s] is the time it takes for gas particles to travel from the high-temperature sensor to the low-temperature sensor;

[0194] V c [m 3 [ ] is the control volume defined as the gas volume, which includes the volume between the high-temperature sensor and the low-temperature sensor;

[0195] F g [m 3 / s] is the flow rate of the flue gas, specifically measured by flow measurement devices 60 and 61.

[0196] Furthermore, the control unit is configured to define a comparison between a reference parameter and at least one threshold. The threshold may include a temperature value and / or a flow rate value related to the reference parameter. In other words, if the reference parameter is based on temperature or flow rate, the relevant threshold will be the temperature or flow rate threshold.

[0197] For example, if the reference parameter based on the cooling parameters is below the cooling rate threshold, the control unit commands the adjusting member to be in a first position; alternatively, if the cooling parameters are above the cooling rate threshold, the control unit commands the adjusting members 40 and 41 to be in a second position. The cooling rate threshold can be set between 200°C / sec and 400°C / sec, specifically between 200°C / sec and 250°C / sec, or between 250°C / sec and 300°C / sec, or between 300°C / sec and 350°C / sec, or between 350°C / sec and 400°C / sec: this cooling rate range can help prevent or reduce the growth of dioxins and furans in the flue gas.

[0198] Alternatively, if a reference parameter based on the temperature change across the first heat exchange chamber 11 and / or the second heat exchange chamber 12 is lower than the corresponding temperature change threshold, the control unit commands the regulating member to be in the first position; alternatively, if the temperature change is higher than the temperature change threshold, the control unit commands the regulating members 40, 41 to be in the second position.

[0199] According to the overall concept, the treatment equipment is configured to cool the flue gas from a temperature between 550°C and 700°C (i.e., a temperature close to the output temperature of the flue gas from gas source 20) to a lower temperature between 150°C and 300°C, more particularly between 230°C and 270°C, and even more particularly 250°C. Therefore, the temperature change threshold—which represents the required temperature change across the heat exchange chamber—is between 280°C and 550°C, more particularly between 350°C and 450°C.

[0200] Although the above description refers to the first heat exchange chamber 11 and the second heat exchange chamber 12, the processing equipment 1 may include other heat exchange chambers, particularly a third or fourth heat exchange chamber, which has an inlet and an outlet configured to receive and discharge flue gas, respectively. The other heat exchange chambers may include other heat exchange units, each arranged in one of the other heat exchange chambers and having the same characteristics as the heat exchange units described above.

[0201] From the perspective of the working fluid, these additional exchange chambers are connected to a single steam tank 110, thus allowing the system to operate correctly even when the flow of hot smoke is only active in some branches and not in others.

Claims

1. A treatment device (1) for hot flue gas discharged from an industrial plant, said treatment device (1) comprising a gas circuit and a fluid circuit, The gas circuit includes: - A first heat exchange chamber (11) and a second heat exchange chamber (12), both of which include a corresponding gas inlet and a gas outlet, the first heat exchange chamber (11) and the second heat exchange chamber (12) being configured to receive the flue gas in the gas inlet; - First flue gas supply pipe (23) and second flue gas supply pipe (24), the first flue gas supply pipe (23) and the second flue gas supply pipe (24) respectively connect the gas inlet of the first heat exchange chamber (11) and the gas inlet of the second heat exchange chamber (12) to the flue gas source (20); - A first flue gas discharge duct (25) and a second flue gas discharge duct (26), the first flue gas discharge duct (25) and the second flue gas discharge duct (26) being connected to the gas outlet of the first heat exchange chamber (11) and the gas outlet of the second heat exchange chamber (12), respectively, and the first flue gas discharge duct (25) and the second flue gas discharge duct (26) being configured to transport the flue gas away from the first heat exchange chamber (11) and the second heat exchange chamber (12). The first flue gas supply pipe (23), the first flue gas discharge pipe (25) and the first heat exchange chamber (11) define the first branch of the gas circuit, while the second flue gas supply pipe (24), the second flue gas discharge pipe (26) and the second heat exchange chamber (12) define the second branch of the gas circuit. - At least one of a temperature measuring device and a flow measuring device, the temperature measuring device and the flow measuring device being configured to provide a representative signal of the temperature and a representative signal of the flow rate of the flue gas, respectively; - At least one adjusting member, said at least one adjusting member being movable between at least the following two: In the first position, the flue gas is allowed to be transported from the flue gas source (20) to the first heat exchange chamber (11), while preventing or reducing the transport of flue gas from the flue gas source (20) to the second heat exchange chamber (12), and 〇 Second position, in which the flue gas is allowed to be transported from the flue gas source (20) to both the first heat exchange chamber (11) and the second heat exchange chamber (12); The fluid circuit is configured to deliver working fluids in both liquid and gas phases, and the fluid circuit includes: - A first heat exchange unit (101) and a second heat exchange unit (103), the first heat exchange unit (101) and the second heat exchange unit (103) being respectively arranged in the first heat exchange chamber (11) and the second heat exchange chamber (12) or in thermal contact with the first heat exchange chamber (11) and the second heat exchange chamber (12) and configured to allow heat exchange between the flue gas and the working fluid; - A steam tank (110) which is at least fluidly connected to the first heat exchange unit (101) and the second heat exchange unit (103). Furthermore, the processing device (1) further includes a control unit (200), which is configured to: - Receive at least one of a representative signal of the temperature of the flue gas and a representative signal of its flow rate; - Determine at least one of the temperature value and the flow rate value based on the corresponding representative signal; - The reference parameter is defined based on at least one of the temperature value or the flow rate value of the flue gas; - Defines the comparison between the reference parameter and at least one threshold; - Based on the comparison, the at least one adjusting member is commanded to be in the first position or in the second position.

2. The processing apparatus (1) according to claim 1, wherein, The gas circuit includes both the temperature measuring device and the flow measuring device, and the reference parameter is based on both the temperature value and the flow rate value of the flue gas.

3. The processing apparatus (1) according to claim 1, wherein, The gas circuit includes the temperature measuring device, which includes at least one high-temperature sensor disposed upstream of the first heat exchange chamber (11) and / or the second heat exchange chamber (12). Furthermore, the temperature measuring device includes at least one low-temperature sensor disposed downstream of the first heat exchange chamber (11) and / or the second heat exchange chamber (12). The control unit is configured to determine the temperature change parameter as the difference between the temperature value measured by the at least one high-temperature sensor and the temperature value measured by the at least one low-temperature sensor. The reference parameter is based on the temperature change parameter.

4. The processing apparatus (1) according to claim 1, wherein, The temperature measuring device includes: a first high-temperature sensor (50), which is arranged upstream of the first heat exchange chamber (11) on the first flue gas supply pipe (23); and a second high-temperature sensor (51), which is separate from the first high-temperature sensor (50) and is arranged upstream of the second heat exchange chamber (12) on the second flue gas supply pipe (24). Furthermore, the temperature measuring device further includes: a first low-temperature sensor (50a), which is arranged downstream of the first heat exchange chamber (11) on the first flue gas emission pipe (25); and a second low-temperature sensor (51a), which is arranged downstream of the second heat exchange chamber (12) on the second flue gas emission pipe (26).

5. The processing device (1) according to claim 1, in, The gas circuit includes the temperature measuring device, which includes at least one high-temperature sensor disposed upstream of the first heat exchange chamber (11) and / or the second heat exchange chamber (12), and wherein the temperature measuring device includes at least one low-temperature sensor disposed downstream of the first heat exchange chamber (11) and / or the second heat exchange chamber (12), the control unit being configured to determine a temperature change parameter as the difference between a temperature value measured by the at least one high-temperature sensor and a temperature value measured by the at least one low-temperature sensor, the reference parameter being based on the temperature change parameter, or The temperature measuring device includes: a first high-temperature sensor (50), which is arranged upstream of the first heat exchange chamber (11) on the first flue gas supply pipe (23); and a second high-temperature sensor (51), which is separate from the first high-temperature sensor (50) and is arranged upstream of the second heat exchange chamber (12) on the second flue gas supply pipe (24). The temperature measuring device also includes: a first low-temperature sensor (50a), which is arranged downstream of the first heat exchange chamber (11) on the first flue gas discharge pipe (25); and a second low-temperature sensor (51a), which is arranged downstream of the second heat exchange chamber (12) on the second flue gas discharge pipe (26). The control unit (200) is configured to determine at least one of the following: - A first temperature change parameter, representing the temperature difference between the upstream and downstream sections of the flue gas in the first heat exchange chamber (11), and - A second temperature variation parameter, which represents the temperature difference between the upstream and downstream sections of the flue gas in the second heat exchange chamber (12). The reference parameter is based on at least one of the first temperature change parameter and the second temperature change parameter, or a combination of the first temperature change parameter and the second temperature change parameter.

6. The processing apparatus (1) according to claim 5, wherein, The control unit is configured to: - Compare at least one of the first temperature change parameter and the second temperature change parameter with the corresponding temperature change threshold; - If the temperature change parameter is lower than the corresponding temperature change threshold, then the at least one regulating member is commanded to be in the first position; - If the temperature change parameter is higher than the corresponding temperature change threshold, then the at least one regulating member is commanded to be in the second position.

7. The processing apparatus (1) according to claim 6, wherein, The temperature change threshold is between 200°C and 600°C.

8. The processing apparatus (1) according to claim 6, wherein, The temperature change threshold is between 350°C and 450°C.

9. The processing apparatus (1) according to any one of claims 5, 6, 7 or 8, wherein, The first heat exchange chamber (11) and the second heat exchange chamber (12) are configured to determine the cooling process of the flue gas, and the control unit (200) is configured to: - Cooling parameters are determined based on the flow rate value and temperature change parameters of the flue gas, the cooling parameters representing the current cooling rate of the flue gas; - Set a cooling rate threshold, which is between 200°C / second and 400°C / second; - Compare the cooling parameter with the cooling rate threshold. - If the cooling parameter is lower than the cooling rate threshold, then the at least one adjusting member is commanded to be in the first position; The reference parameter is based on the cooling parameter and at least one threshold including the cooling rate threshold.

10. The processing apparatus (1) according to claim 9, wherein, If the cooling parameter is higher than the cooling rate threshold, the control unit (200) is configured to command the at least one regulating member to be in the second position.

11. The processing apparatus (1) according to claim 9, wherein the cooling rate threshold is between 200°C / sec and 250°C / sec, or between 250°C / sec and 300°C / sec, or between 300°C / sec and 350°C / sec, or between 350°C / sec and 400°C / sec.

12. The processing apparatus (1) according to claim 9, wherein, The cooling parameters are calculated according to the following formula: ,in, in: C 速率 [ΔC° / s] is the cooling parameter; ΔT [°C] is the temperature change across the first heat exchange chamber (11) and / or the second heat exchange chamber (12); t pg [s] is the time it takes for the gas particles to travel from the high-temperature sensor to the low-temperature sensor; V c [m 3 [ ] is a control volume defined as the gas volume, the gas volume being included between the high-temperature sensor and the low-temperature sensor; F g [m 3 [ / s] is the flow rate of the flue gas.

13. The processing apparatus (1) according to claim 12, wherein, ΔT [°C] is the temperature change across the first heat exchange chamber (11) and / or the second heat exchange chamber (12), calculated as the difference between the temperature measured by the high-temperature sensor and the temperature measured by the low-temperature sensor. g [m 3 / s] is the flow rate of the flue gas measured by the flow measurement device.

14. The processing apparatus (1) according to claim 1, wherein, The step of defining the reference parameters includes determining the flow rate of the flue gas, and the control unit is further configured to: - Compare the traffic flow with the corresponding traffic threshold; - If the flow rate is lower than the corresponding flow rate threshold, then the at least one regulating member is commanded to be in the first position.

15. The processing apparatus (1) according to claim 14, wherein, The control unit is further configured to: if the flow rate is higher than the corresponding flow rate threshold, command the at least one regulating member to be in the second position.

16. The processing apparatus (1) according to claim 1, wherein, The flow measurement device includes a first flow sensor (60) and a second flow sensor (61), which are respectively arranged on the first branch and the second branch of the gas circuit, and each flow sensor is configured to provide a signal representing the flow rate of the flue gas entering the first branch and the second branch, respectively. The control unit is configured to receive a representative signal of the flow rate and determine a first flow rate value and a second flow rate value for the flue gas in the first branch and the second branch. The reference parameters are based on the first flow rate value and the second flow rate value.

17. The processing apparatus (1) according to claim 16, wherein, The first flow sensor (60) and the second flow sensor (61) are respectively arranged on the following: - The first flue gas supply pipe (23) and the second flue gas supply pipe (24), or - The first flue gas emission pipe (25) and the second flue gas emission pipe (26).

18. The processing apparatus (1) according to claim 1, wherein, The at least one adjusting member includes at least one of the following: - A first damper and a second damper, the first damper and the second damper being respectively arranged on the first branch and the second branch of the gas circuit. - A first booster and a second booster, the first booster and the second booster being respectively arranged on the first branch and the second branch of the gas circuit.

19. The processing apparatus (1) according to claim 18, wherein: - The first damper and the second damper are arranged on the following: 〇 The first flue gas supply pipe (23) and the second flue gas supply pipe (24), or 〇 The first flue gas emission pipe (25) and the second flue gas emission pipe (26).

20. The processing apparatus (1) according to claim 18, wherein: - The first booster and the second booster include a fan configured to promote or inhibit the flow of the flue gas within the gas circuit, and the first booster and the second booster include an electric motor configured to rotate the fan.

21. The processing apparatus (1) according to claim 1, wherein, The heat exchange between the flue gas and the working fluid determines the transition of the working fluid from a liquid phase to a gas phase, and this transition determines the flow of the working fluid through the fluid loop. Furthermore, the transformation also determines that the gaseous working fluid is transported from at least one of the first heat exchange unit (101) and the second heat exchange unit (103) toward the steam tank (110). And among them: - When the at least one regulating member is arranged in the first position, the steam tank (110) is configured to receive the gaseous working fluid from the first heat exchange unit (101) and to deliver the liquid working fluid to the first heat exchange unit (101); and - When the at least one regulating member is arranged in the second position, the steam tank (110) is configured to receive the gaseous working fluid from both the first heat exchange unit (101) and the second heat exchange unit (103), and to deliver the liquid working fluid to both the first heat exchange unit (101) and the second heat exchange unit (103).

22. The processing apparatus (1) according to claim 21, wherein, When the at least one regulating member is arranged in the first position, the steam tank (110) is configured to receive the gaseous working fluid from the first heat exchange unit (101) and deliver the liquid working fluid to the first heat exchange unit (101), wherein no working fluid flows from the second heat exchange unit to the steam tank.

23. The processing apparatus (1) according to claim 1, wherein: - When the at least one adjusting member is arranged in the first position, heat exchange occurs in the first heat exchange chamber (11), while heat exchange is prevented in the second heat exchange chamber (12); as well as - When the at least one adjusting member is arranged in the second position, heat exchange occurs in both the first heat exchange chamber (11) and the second heat exchange chamber (12).

24. The processing apparatus (1) according to claim 1, wherein, The fluid circuit includes: - A first delivery conduit (111) fluidly connects the outlet of the first heat exchange unit (101) to the steam tank (110), and the first delivery conduit (111) is configured to deliver the working fluid in the gas phase from the first heat exchange unit (101) to the steam tank (110). - A first return pipe (112) connects the inlet of the first heat exchange unit (101) to the steam tank (110) and is configured to deliver the working fluid in liquid phase from the steam tank (110) to the first heat exchange unit (101). - A second delivery conduit (113) fluidly connects the outlet of the second heat exchange unit (103) to the steam tank (110), and the second delivery conduit (113) is configured to deliver the working fluid in the gas phase from the second heat exchange unit (103) to the steam tank (110). - A second return pipe (114) connects the inlet of the second heat exchange unit (103) to the steam tank (110) and is configured to deliver the working fluid in liquid phase from the steam tank (110) to the second heat exchange unit (103).

25. The processing apparatus (1) according to claim 1, wherein, The fluid circuit includes a working fluid source (70) and at least one fluid delivery conduit connecting the working fluid source (70) to the steam tank (110), the working fluid source (70) being configured to deliver working fluid to the steam tank (110). Furthermore, the fluid circuit includes at least one auxiliary heat exchange unit, which is arranged in or in thermal contact with the first heat exchange chamber (11) and / or the second heat exchange chamber (12), and the at least one auxiliary heat exchange unit is configured to heat the working fluid flowing from the working fluid source (70) toward the steam tank (110). The at least one auxiliary heat exchange unit includes a first auxiliary heat exchange unit (102) and a second auxiliary heat exchange unit (104), the first auxiliary heat exchange unit (102) and the second auxiliary heat exchange unit (104) being respectively arranged in the first heat exchange chamber (11) and the second heat exchange chamber (12) or in thermal contact with the first heat exchange chamber (11) and the second heat exchange chamber (12), and the first auxiliary heat exchange unit (102) and the second auxiliary heat exchange unit (104) being configured to heat the working fluid flowing from the working fluid source (70) toward the steam tank (110).

26. The processing apparatus (1) according to claim 1, wherein, The first heat exchange unit (101) defines a first surface for heat exchange between the flue gas and the working fluid, and the second heat exchange unit (103) defines a second surface for heat exchange between the flue gas and the working fluid, wherein the first surface is different from the second surface. The at least one adjusting member is movable in a third position, in which the transport of flue gas from the flue gas source (20) to the first heat exchange chamber (11) is prevented or reduced, while the transport of flue gas from the flue gas source (20) to the second heat exchange chamber (12) is allowed.

27. The processing apparatus (1) according to claim 26, wherein, The first heat exchange chamber (11) has different channel sections relative to the second heat exchange chamber (12) to achieve different flow rates of the flue gas.

28. The processing apparatus (1) according to claim 26, wherein, The first surface is lower than the second surface.

29. The processing apparatus (1) according to claim 1, wherein, The first branch of the gas circuit is arranged parallel to the second branch of the gas circuit according to the flue gas supply direction of the flue gas source (20).

30. The processing apparatus (1) according to claim 1, wherein, The first heat exchange chamber (11) is directly connected to the flue gas source (20) through the first flue gas supply pipe (23), and the second heat exchange chamber (12) is directly connected to the flue gas source (20) through the second flue gas supply pipe (24). The first flue gas supply pipe (23) and the second flue gas supply pipe (24) are different.

31. The processing apparatus (1) according to claim 30, wherein, The first flue gas supply duct (23) and the second flue gas supply duct (24) are arranged parallel to each other.

32. The processing apparatus (1) according to claim 1, wherein, Under at least one operating condition, the second heat exchange chamber (12) is configured to receive a large amount of flue gas that has not yet passed through the first heat exchange chamber (11).

33. The processing apparatus (1) according to claim 1, wherein, The first flue gas supply pipe (23) and the second flue gas supply pipe (24) are connected to the same flue gas source (20).

34. The processing apparatus (1) according to claim 1, wherein, The steam tank (110) is shared by the first heat exchange unit (101) and the second heat exchange unit (103).

35. The processing apparatus (1) according to claim 1, wherein, The fluid circuit includes: - A first delivery conduit (111), the first delivery conduit (111) being connected to the outlet of the first heat exchange unit (101) of the first heat exchange chamber (11) and configured to deliver the working fluid from the first heat exchange unit (101) to the steam tank (110); and - A second delivery conduit (113) is connected to the outlet of the second heat exchange unit (103) of the second heat exchange chamber (12) and configured to deliver the working fluid from the second heat exchange unit (103) to the steam tank (110).

36. A method for treating hot flue gas discharged from an industrial plant, said method being performed by a treatment apparatus according to any one of claims 1 to 35, said treatment apparatus comprising a gas circuit and a fluid circuit. The gas circuit includes: - A first heat exchange chamber (11) and a second heat exchange chamber (12), both of which include a corresponding gas inlet and a gas outlet, the first heat exchange chamber (11) and the second heat exchange chamber (12) being configured to receive the flue gas in the gas inlet; - First flue gas supply pipe (23) and second flue gas supply pipe (24), the first flue gas supply pipe (23) and the second flue gas supply pipe (24) respectively connect the gas inlet of the first heat exchange chamber (11) and the gas inlet of the second heat exchange chamber (12) to the flue gas source (20); - A first flue gas discharge duct (25) and a second flue gas discharge duct (26), the first flue gas discharge duct (25) and the second flue gas discharge duct (26) being connected to the gas outlet of the first heat exchange chamber (11) and the gas outlet of the second heat exchange chamber (12), respectively, and the first flue gas discharge duct (25) and the second flue gas discharge duct (26) being configured to transport the flue gas away from the first heat exchange chamber (11) and the second heat exchange chamber (12). The first flue gas supply pipe (23), the first flue gas discharge pipe (25) and the first heat exchange chamber (11) define the first branch of the gas circuit, while the second flue gas supply pipe (24), the second flue gas discharge pipe (26) and the second heat exchange chamber (12) define the second branch of the gas circuit. - At least one of a temperature measuring device and a flow measuring device, the temperature measuring device and the flow measuring device being configured to provide a representative signal of the temperature and a representative signal of the flow rate of the flue gas, respectively; - At least one adjusting member, said at least one adjusting member being movable between at least the following two: In the first position, the flue gas is allowed to be transported from the flue gas source (20) to the first heat exchange chamber (11), while preventing or reducing the transport of flue gas from the flue gas source (20) to the second heat exchange chamber (12), and 〇 Second position, in which the flue gas is allowed to be transported from the flue gas source (20) to both the first heat exchange chamber (11) and the second heat exchange chamber (12); The fluid circuit is configured to deliver working fluids in both liquid and gas phases, and the fluid circuit includes: - A first heat exchange unit (101) and a second heat exchange unit (103), the first heat exchange unit (101) and the second heat exchange unit (103) being respectively arranged in the first heat exchange chamber (11) and the second heat exchange chamber (12) or in thermal contact with the first heat exchange chamber (11) and the second heat exchange chamber (12) and configured to allow heat exchange between the flue gas and the working fluid; - A steam tank (110) which is at least fluidly connected to the first heat exchange unit (101) and the second heat exchange unit (103). The method includes at least the following steps performed by the processing device (1): - Receive at least one of a representative signal of the temperature of the flue gas and a representative signal of its flow rate; - Determine at least one of the representative temperature value and the representative flow rate value based on the corresponding representative signal; - The reference parameter is defined based on at least one of the temperature value or the flow rate value of the flue gas; - Defines the comparison between the reference parameter and at least one threshold; - Based on the comparison, the at least one adjusting member is commanded to be in the first position or in the second position.

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