ES2999292T3 - Pulse combustion dryer - Google Patents

Abstract

Pulsed combustion dryer comprising a pulsed combustion burner having a pulsed combustion chamber, a drying chamber, and an exhaust pipe connected to the pulsed combustion chamber and the drying chamber. The pulsed combustion dryer also comprises hydrogen and oxygen inlets for feeding hydrogen and oxygen to the pulsed combustion chamber, respectively, a product feed line for feeding the product to be dried to the drying chamber, a particle separation system for separating the dried product from water vapor, and a steam outlet line for evacuating the water vapor. The steam outlet line is connected to a steam supply line such that at least some of the water vapor is directed toward the pulsed combustion chamber to cool the hot flue gas passing into the drying chamber. The oxygen inlet is arranged in the steam supply line to mix oxygen and water vapor passing toward the pulsed combustion burner. (Automatic translation with Google Translate, no legal value)

Description

DESCRIPTION

Pulse combustion dryer

Technical field

The present invention relates to a device for drying liquid or pasty products by applying a pulsed flow of heated gas incident on the products. In particular, the invention relates to a pulsed combustion dryer or pulsed combustion dryer with atomization comprising a pulsed combustion burner that uses hydrogen as fuel and oxygen as an oxidizing agent for combustion.

State of the art

A pulse combustion dryer, or pulse combustion dryer with atomization, is a type of dryer that atomizes liquids or pastes inside a drying chamber. A pulse combustion burner is used to generate the atomization.

A pulsed combustion burner has a cylindrical combustion chamber into which fuel (usually a gaseous fuel such as natural gas, propane, LPG, etc., or a liquid fuel) is injected continuously. Air, on the other hand, is introduced in a pulsating manner, meaning that air is introduced through a valve that opens and closes between 50 and 500 times per second, or at higher frequencies. This results in a pulsating or oscillating combustion, at the same frequency. The combustion chamber exits through a narrow exhaust pipe. The combustion gases, the heat of combustion, and a series of pulses, each occurring between 50 and 500 times per second or more, exit the combustion chamber through the exhaust pipe. When the pulse frequency roughly equals the natural resonance of the combustion chamber and/or exhaust pipe, the combustion reaches resonance, and the pulses achieve greater amplitude or pressure oscillation. Pulse-fired burners are widely described in the prior art. In some configurations, pulse-fired burners operate without valves, and the combustion pulse can draw in air without the need for valves. Known fuels used in pulse-fired dryers are combustible gases such as natural gas, methane, or hydrogen, and liquid fuels such as alcohol.

The end of the exhaust pipe is connected to a drying chamber, at which point a liquid or paste-like product is introduced through a suitable injector. Strong pressure pulses or oscillations break the liquid or paste into thousands of tiny droplets, and the hot flue gas stream accelerates these droplets to near the speed of sound, dramatically increasing heat and mass transfer rates. As a result, atomization is generated within the drying chamber that evaporates the water from the droplets in an extremely short time, without overheating the product, transforming the liquid or paste-like product to be dried into a dry powder.

The dry dust, flue gases, and evaporated moisture leave the drying chamber and head toward a dust separation system, typically a cyclone and/or bag filter. At the end, an extraction fan draws the gases into a chimney.

EP1092060B1 discloses a pulse combustion dryer for dehydrating a fibrous web in papermaking using an unspecified fuel.

US20170314778A1 discloses a pulse combustion dryer that can use hydrogen as fuel, wherein the burner is designed to generate a pulsating flame to generate a pulsating hot gas flow as a swirl burner having a diffuser as an element at its outlet.

Document US20170307211A1 discloses a pulse combustion dryer that can use hydrogen as fuel, wherein an externally actuatable pulsation device for at least a part of the mass flow directed to the burner is arranged upstream in the pipe leading to the flame.

US20070251120A1 discloses a pulse combustion dryer capable of using hydrogen as fuel comprising a processing engine for generating a high velocity air stream and directing the high velocity air stream toward an acceleration tube, the high velocity air stream having a volume, heat, and velocity sufficient to vaporize substantially all of the water present in a stream of organic material; a working chamber mounted to the acceleration tube of the processing engine, the high velocity air stream having a path toward the working chamber, and the working chamber terminating within a micronization dryer; and an injection pump for injecting the organic material into the working chamber so that its interaction with the high velocity air stream occurs.

EP236152A1 discloses a pulse combustion dryer that can use hydrogen as fuel, comprising a line located upstream of the flame connected to an independent source, externally actuated pulsation device for at least a part of the mass flow directed to the burner.

An operating problem with the burner of a pulse-fired dryer using hydrogen and oxygen under stoichiometric conditions is that the combustion temperature will exceed 1500 °C. Such a high combustion temperature can melt or severely damage the burner. The solution to this problem according to the prior art is basically to circulate cooling water within the walls of the pulse-fired burner, by means of, for example, a cooling jacket or cooling coil, which makes the burner construction complex and the operation of the pulse-fired dryer risky in the event of a cooling water failure during operation.

Description of the invention

A first aspect of the invention relates to a pulse combustion dryer in which hydrogen is used as fuel and where the exhaust gases from the pulse combustion dryer are efficiently used to regulate the temperature in the pulse combustion burner.

A second aspect of the invention relates to a pulse combustion dryer using hydrogen as fuel, which does not require cooling water to circulate within the walls to lower the combustion temperature below 1500 °C.

A third aspect of the invention relates to a pulse combustion dryer that allows a portion of the water vapor exiting the dryer to be recirculated in the combustion chamber of the pulse combustion burner to cool the pulse combustion burner.

According to the invention, there is provided a pulse combustion dryer comprising

a pulse combustion burner having a cylindrical pulse combustion chamber for generating pulse combustion, a drying chamber and an exhaust pipe connected to the pulse combustion chamber for receiving and pressurizing pulses of hot combustion gas, and to the drying chamber for receiving pressurized pulses of hot combustion gas,

a hydrogen inlet for feeding hydrogen into the combustion chamber in a pulsed manner,

an oxygen inlet to supply oxygen to the combustion chamber in a pulsed manner,

a product feed line for feeding a liquid or pasty product to be dried into the drying chamber to produce a water vapor atomization and dried product powder,

a dust separation system having at least one dust outlet connected to the drying chamber for separating the dried product dust from water vapor from the drying chamber,

a steam outlet line connected to the dust separation system to evacuate water vapor, where

the steam outlet line is connected to a steam supply line that is connected to at least one steam inlet of the pulse firing burner, the steam supply line being configured to divert at least a portion of the water vapor passing through the steam outlet line to the at least one steam inlet of the pulse firing burner to enter the pulse firing chamber as a quenching medium at a steam rate sufficient to cool the hot flue gas passing into the drying chamber, or firing temperature, to a gas temperature reduced to between 300°C and 1200°C;

The oxygen inlet is arranged in a portion of the steam supply line to mix oxygen and water vapor passing through the steam supply line to the at least one steam inlet of the pulse combustion burner.

The flow rate and velocity at which water vapor is diverted to and introduced into the pulse combustion chamber can depend on several factors, including the temperature difference between the inside of the pulse combustion chamber and the water vapor, the volume of the pulse combustion chamber, and how much the temperature of the hot flue gas entering the drying chamber will be reduced, among others.

In some embodiments, the product feed line may comprise a free end with an injector arranged within or at the end of the exhaust pipe for injecting the product to be dried into the drying chamber.

In some embodiments, the pulse combustion dryer may further comprise at least one steam blower disposed in the steam supply line for drawing water vapor from the steam outlet line.

In some embodiments, the steam supply line comprises:

a first branch connected to a first steam inlet of the pulse combustion burner, a second branch connected to a second steam inlet of the pulse combustion burner, a first steam blower disposed in the first branch to draw a first portion of water vapor from the steam outlet line to provide basic water vapor entering the pulse combustion chamber at a basic rate sufficient to reduce the combustion temperature or to cool hot flue gas passing into the drying chamber to a first reduced gas temperature, and a second steam blower disposed in the second branch to draw a second portion of water vapor from the steam outlet line to provide additional water vapor entering or surrounding the pulse combustion chamber or the exhaust pipe, together with the basic water vapor, at an additional rate sufficient, to cool the hot flue gas passing into the drying chamber to a second reduced gas temperature.

In some embodiments, the oxygen inlet is arranged in the first branch downstream of the first steam blower.

In some embodiments, the pulse combustion dryer may further comprise a suction fan arranged in the steam outlet line at a position between the steam supply line and the connection of the outlet line to the dust separation system to maintain a vacuum pressure of 1 to 50 mbar below atmospheric pressure in the drying chamber.

In some embodiments, a valve, for example, a rotary valve, may be disposed in the steam supply line upstream of the at least one steam inlet of the pulse-combustion burner. The valve is configured to operate such that it can provide a pulsed flow of water vapor entering the pulse combustion chamber.

In some embodiments, the separation system comprises a cyclone connected to an outlet of the drying chamber and to the steam outlet line.

In other embodiments, the separation system comprises a bag filter connected to an outlet (9a) of the drying chamber and to the steam outlet line.

In still further embodiments, the separation system comprises a cyclone connected to an outlet of the drying chamber and a bag filter connected to the cyclone and to the steam outlet line.

In further embodiments, the separation system comprises a cyclone connectable to an outlet of the drying chamber and to the steam outlet line, and a bag filter connectable to the cyclone and to the outlet of the drying chamber, and connected to the steam outlet line.

In some embodiments, the steam outlet line may contain a filter, such as an activated carbon filter or the like, to remove volatile organic compounds that may volatilize from the dried product during the drying process. These volatile organic compounds are removed, in particular, from the water vapor once it has been separated from the dried product.

The pulse combustion dryer according to the invention provides some advantages, for example:

- The water vapor contained in the generated exhaust gases is used as a cooling medium for the pulse combustion burner.

- Basically, there is no free oxygen present in the drying medium, making the atmosphere inside the dryer a non-explosive atmosphere.

- The drying medium will not oxidize the product to be dried.

- Exhaust gas treatment to eliminate odors will be minimized or not necessary.

- No combustion products are generated by fuels containing carbon that could come into contact with the product to be dried.

- NOx is not generated during combustion, since there is no N2 present in combustion.

Other aspects, advantages and features of the invention become apparent from this specification and the drawings.

Brief description of the drawings

To complete the description and to provide a better understanding of the invention, a drawing is provided. Said drawing forms an integral part of the description and illustrates an embodiment of the invention, which should not be construed as a restriction on the scope of the invention, but merely as an example of how the invention can be carried out. The drawing comprises the following figure:

Figure 1 shows a schematic view of an embodiment of a pulse combustion dryer according to the invention.

The reference signs in this drawing have the following meanings:

1 Product tank to contain the liquid or pasty product to be dried

1st Product feeding line

2 Feed pump for the liquid or pasty product to be dried

3 Injector of the liquid or pasty product to be dried

4 Pulse combustion burner

4a Exhaust pipe

4b Pulse combustion chamber

5 Hydrogen gas train

6 Gaseous oxygen train

7 First steam blower

8 Second steam blower for temperature control around the product injector

9 Drying chamber

9th Exit

9b Starting line

9c Detour line

10 Cyclone for dry dust separation

10th Starting Line

10b Dust outlet

10c Detour line

11 Bag filter

11th Starting Line

11b Dust outlet

12 Suction fan

13 Steam outlet

13a Steam outlet line

14 Steam supply line

14a First branch of the steam supply line

14b Second branch of the steam supply line

15 First check valve

15a Second check valve

16 Third check valve

16a Fourth check valve

H2 Hydrogen

O2 Oxygen

Description of the ways of carrying out the invention

In the embodiment shown in Figure 1, the pulse combustion dryer comprises a product tank 1 for containing a liquid or pasty product to be dried, an injector 3, a pulse combustion burner 4, a drying chamber 9, a cyclone 10 and a bag filter 11.

The tank 1 is connected to an exhaust pipe 4a of the pulse combustion burner 4 via a product feed line 1a to the injector 3 which is arranged at the end of the exhaust pipe 4a. The exhaust pipe 4a connects an outlet of the pulse combustion burner 4 to an inlet of the drying chamber 9. The pulse combustion burner 4 comprises a combustion chamber 4b and a hydrogen inlet connected to a hydrogen gas train 5. A feed pump 2 is arranged in the product feed line 1a.

The drying chamber 9 comprises an outlet 9a which is connected by an outlet line 9b to an inlet of the cyclone 10, and also to a first bypass line 9c which is connected to an inlet of the bag filter 11. A first check valve 15 is placed in the first bypass line 9c to open or close access to the first bypass line 9c and a second check valve 15a is placed in the outlet line 9b between the inlet of the cyclone 10 and the connection of the outlet line 9a and the first bypass line 9c, to open or close the outlet line 9a. In the embodiment shown, the cyclone 10 and the bag filter 11 constitute a particle separation system. In other embodiments, the particle separation system comprises only the cyclone 10 or only the bag filter 11.

The cyclone 10 comprises an outlet which is connected to an inlet of the bag filter 11 via an outlet line 10a, and to a second bypass line 10c connected to the vapor outlet line 13a. The bag filter 11 comprises a vapor evacuation outlet 11a which is also connected to the vapor outlet line 13a. A third check valve 16 is connected in the outlet line 10a to open or close access to the outlet line 10a, and a fourth check valve 15a is arranged in the second bypass line 10c to open or close access to the second bypass line 10c.

A steam supply line 14, 14a, 14b branches off from the steam outlet line 13a, downstream of the steam evacuation outlet 11a of the bag filter 11 and the connection of the second bypass line 10c to the steam outlet line 13a. A suction fan 12 is arranged in the steam outlet line 13a at a position between the steam supply line 14 and the steam evacuation outlet 11a of the bag filter 11 and the connection of the second bypass line 10c to the steam outlet line 13a.

The steam supply line 14 comprises a first branch 14a and a second branch 14b, each of which is connected to a respective steam inlet of the pulse combustion burner 4. A first steam blower 7 is arranged in the first branch 14a and a gaseous oxygen train 6 is connected to the first between the first steam blower 7 and the corresponding steam inlet of the pulse combustion burner 4. A second steam blower 8 is arranged in the second branch 14a of the steam supply line 14.

During operation, the liquid or pasty product to be dried is pumped by pump 2 through the product feed line 1a, from the product tank 1 to the injector 3 which is inside the exhaust pipe 4a of the pulse combustion burner 4.

The pulse combustion burner 4 uses hydrogen H2 as fuel and oxygen O2 as the oxidizing agent for combustion. The hydrogen flow can come from an in situ electrolysis process or any other conventional hydrogen source. The hydrogen is introduced into the pulse combustion burner 4 via a suitable hydrogen gas train 5, at a constant mass flow rate.

Instead of using a blower to introduce combustion air into the pulse combustion burner 4, as conventional pulse combustion burners do, according to this invention, a first steam blower 7 introduces water vapor into the pulse combustion burner 4. Preferably, the water vapor is introduced through a valve, for example a rotary valve, (not shown in Figure 1), because this allows the frequency of the pulsing to be controlled, independent of other combustion parameters such as the combustion temperature. When a valveless pulse combustion burner 4 is used, the water vapor will enter the pulse combustion burner 4 without the need for valves or a blower, by utilizing the suction provided by the pulses from the pulse combustion burner 4 itself.

The steam blower 7 draws a portion of the water vapor flowing through the steam outlet line 13a into the steam supply line 14, which means that a portion of the water vapor is recirculated after the product has been dried, and there is no need for a specific water vapor generator or an external water vapor supply.

Pure oxygen O2 provided by the gaseous oxygen train 6 is introduced into the first branch 14a of the steam supply line 14, as the oxidizing agent for combustion in the combustion chamber 4b of the pulse-fired burner 4. This supplied oxygen may be from an in-situ electrolysis process, an air purification process, or may be from any other conventional oxygen source. The oxygen is introduced via a suitable gaseous oxygen train 6, at a constant mass flow rate.

The mass flow of hydrogen is constant and is directly proportional to the amount of water to be evaporated from the liquid or pasty product to be dried. The mass flow of oxygen is also constant and stoichiometric to the combustion of the hydrogen flow. The flow of water vapor from the first steam blower 7 is controlled by the desired combustion temperature in the pulse-fired burner 4, i.e., when a lower combustion temperature is desired, a higher flow of water vapor is blown and vice versa. Without this adjustable steam flow, the combustion temperature would be above 1500 °C, but by using the adjustable steam flow, the temperature can be cooled down to 300 °C at 1200 °C. No cooling jacket or coil is needed to protect the pulse-fired burner 4 from overheating.

In this way, pure water vapor is the only combustion product in the combustion chamber 4b of the pulse combustion burner 4. In addition, the second steam blower 8 (optional) in the second branch 14b can be used to obtain cooler temperatures around the product injector 3 and to direct the atomization into the drying chamber 9.

Water vapor leaves the pulse-fired burner 4 at a temperature between 300 and 1200 °C, which means that superheated water vapor is the drying medium throughout the entire volume of the drying chamber 9. The water vapor from the pulse-fired burner 4, together with the generated pulses, strikes the liquid or pasty product to be dried, which is introduced through the injector 3. The product is sprayed into the drying chamber 9, and the water in the droplets evaporates rapidly, so that the water vapor in the drying chamber 9 is cooled to a temperature between 300 and 1200 °C to a lower temperature between 100 and 200 °C, depending on the product to be dried. The temperature at which the powder-water vapor mixture leaves the drying chamber 9 is controlled by the flow rate of the product to be dried; if a lower temperature is desired, the flow rate is increased, and vice versa.

To prevent condensation, any point in the drying process between product injector 3 and steam outlet 13 must be at least 100°C at atmospheric pressure. At sub-atmospheric pressures, temperatures below 100°C can be achieved without steam condensation in the pulse-combustion dryer.

After leaving the drying chamber 9 via outlet 9a thereof, the gas mixture, i.e. water vapor from the pulse combustion burner 4 and evaporated moisture from the product to be dried and dust, is conducted via outlet line 9b to the cyclone 10, or via the first diversion line 9c directly to the bag filter 11 via the first diversion line 9c.

The steam/product mixture exiting the drying chamber 9 may be guided through the outlet line 9a of the cyclone 10 only and thence through the second bypass line 10c such that water vapor from the cyclone 11 is guided to the steam outlet line 13a by closing the outlet line 10a by means of the third check valve 16 and opening the second bypass line 10c by means of the fourth check valve 16a. Alternatively, the steam/product mixture exiting the drying chamber 9 may be guided through the outlet line 9a and the first bypass line 9c to the bag filter 11 only such that water vapor from the bag filter 11 is guided to the steam outlet line 13a by opening the first check valve 15 and closing the second check valve 15a. In another alternative, the steam/product mixture exiting the drying chamber 9 is guided to the cyclone 10 via the outlet line 9b by closing the first check valve 15 and opening the second check valve 15a, and from the cyclone 10 to the bag filter 11 via the outlet line 10a by opening the third check valve 16 and closing the fourth check valve 16a, such that water vapor from the bag filter 11 is guided to the steam outlet line 13a. The choice of the flow path of the steam/product mixture exiting the drying chamber 9 only through the cyclone 10 or only through the bag filter 11 or both the cyclone 10 and the bag filter 11 depends on the properties of the product to be dried. The cyclone 10 and the bag filter 11 are provided with respective dust outlets 10b, 11b, allowing the extraction of the dry powder product that has been separated from the water vapor.

The suction fan 12 draws water vapor originating in the drying chamber 9 into the cyclone 10 and/or the bag filter 11, to maintain a slight vacuum pressure of 1 to 50 mbar below atmospheric pressure in the drying chamber. A higher vacuum can be used if low drying temperatures are desired without problems with water vapor condensation. A portion of the water vapor drawn in by the fan 12 through the steam outlet line 13a is drawn into the steam supply line 14 and blown through the first branch 14a by the action of the first steam blower 7 and, when desired, also through the second branch 14b by the action of the second steam blower 8, to the respective steam inlets of the pulse-fired burner 4. In this way, a portion of the water vapor coming from the drying chamber 9 and from which the dried product has been removed is recirculated by the first steam blower 7 and, optionally, by the second steam blower 8, in the pulse-fired burner 4, while the remaining water vapor leaves the pulse-fired dryer through the steam outlet 13.

The gas flow in outlet line 13a is a flow of pure or nearly pure water vapor. The amount of water vapor exiting the pulse combustion dryer 4 through steam outlet 13 is essentially equal to the amount of water evaporated from the product to be dried, plus the water vapor generated during the combustion of hydrogen and oxygen. This makes the pulse combustion dryer operate as a superheated water vapor dryer.

As is evident, the pulse combustion dryer of the invention provides some advantages, for example:

- The water vapor contained in the generated exhaust gases is used as a cooling medium for the pulse combustion burner, and the residual heat contained in the generated exhaust gases can be relatively easy to reuse in other thermal processes such as evaporators.

- Basically, there is no free oxygen present in the drying medium, making the atmosphere inside the dryer a non-explosive atmosphere.

- The drying medium will not oxidize the product to be dried.

- Exhaust gas treatment to eliminate odors will be minimized or not necessary.

- No combustion products are generated by fuels containing carbon that could come into contact with the product to be dried.

- NOx is not generated during combustion, since there is no N2 present in combustion.

In this text, the terms first, second, third, etc., have been used herein to describe devices, elements, or parameters. It is understood that devices, elements, or parameters should not be limited by these terms, as the terms are only used to distinguish one device, element, or parameter from another. For example, the first branch could also be called the second branch, and the second branch could be called the first branch without deviating from the scope of this disclosure.

In this text, the term "comprises" and its derivatives (such as "comprising", etc.) should not be understood in an exclusive sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include other elements, stages, etc.

On the other hand, the invention is obviously not limited to the specific embodiment(s) described herein, but also encompasses any variation that any person skilled in the art may consider (for example, as to the choice of materials, dimensions, components, configuration, etc.), within the general scope of the invention, as defined in the claims.

Claims (13)

1. A pulse combustion dryer comprising a pulse combustion burner (4) having a cylindrical pulse combustion chamber (4b) for generating pulse combustion, a drying chamber (9) and an exhaust pipe (4a) connected to the pulse combustion chamber (4b) for receiving and pressurizing pulses of hot combustion gas, and to the drying chamber (9) for receiving pressurized pulses of hot combustion gas, a hydrogen inlet for feeding hydrogen to the pulse combustion chamber (4b), a product feed line (1a) for feeding a liquid or pasty product to be dried into the drying chamber (9) to produce an atomization of water vapor and powder of dry product, a dust separation system (10, 11) having at least one dust outlet (10b, 11b) connected to the drying chamber (9) for separating the powder from the dried product and the water vapor from the drying chamber (9), a steam outlet line (13a) connected to the dust separation system (10, 11) to evacuate water vapor, characterized in that the pulse combustion dryer further comprises an oxygen inlet for feeding oxygen into the pulse combustion chamber (4b) and that the steam outlet line (13a) is connected to a steam supply line (14, 14a, 14b) which is connected to at least one steam inlet of the pulse firing burner (4), the steam supply line (14, 14a, 14b) for diverting at least a portion of the water vapor passing through the steam outlet line (13a) to the at least one steam inlet of the pulse firing burner (4) to enter the pulse firing chamber (4b) as a cooling medium at a water vapor rate sufficient to cool the hot flue gas passing into the drying chamber (9) to a reduced gas temperature of between 300°C and 1200°C; and The oxygen inlet is arranged in a portion of the steam supply line (14, 14a, 14b) for mixing oxygen and water vapor passing through the steam supply line (14, 14a, 14b) to the at least one steam inlet of the pulse combustion burner (4). 2. The pulse combustion dryer according to claim 1, wherein the product feed line (1a) comprises a free end with an injector (3) arranged inside or at the end of the exhaust pipe (4a) for injecting the product to be dried into the drying chamber (9). 3. The pulse combustion dryer according to claim 1 or 2, comprising at least one steam blower (7, 8) arranged in the steam supply line (14, 14a, 14b) for drawing water vapor from the steam outlet line (13a). 4. The pulse combustion dryer according to claim 1, 2 or 3, wherein the steam supply line (14, 14a, 14b) comprises: a first branch (14a) connected to a first steam inlet of the pulse combustion burner (4), a second branch (14b) connected to a second steam inlet of the pulse combustion burner (4), a first steam blower (7) arranged in the first branch (14a) for drawing a first portion of water vapor from the steam outlet line (13a) to provide a basic water vapor entering the pulse combustion chamber (4b) at a basic rate sufficient to cool the hot flue gas passing into the drying chamber (9) to a first reduced gas temperature, and a second steam blower (8) arranged in the second branch (14b) to draw a second portion of water vapor from the steam outlet line (13a) to provide additional water vapor entering or surrounding the pulse combustion chamber (4b) or the exhaust pipe (4a), together with the basic water vapor, at an additional rate sufficient to cool the hot flue gas passing into the drying chamber (9) to a second reduced gas temperature. 5. The pulse combustion dryer according to claim 4, wherein the oxygen inlet is arranged in the first branch (14a) downstream of the first steam blower (7). 6. The pulse combustion dryer according to any one of claims 1 to 5, comprising a suction fan (12) arranged in the steam outlet line (13) in a position between the steam supply line (14) and the connection of the outlet line (13a) to the dust separation system (10, 11), the suction fan being configured to maintain a vacuum pressure of 1 to 50 mbar below atmospheric pressure in the drying chamber. 7. The pulse combustion dryer according to any one of claims 1 to 6, comprising a valve, preferably a rotary valve, arranged in the steam supply line (14, 14a, 14b) upstream of the at least one steam inlet of the pulse combustion burner (4), to provide a pulsed water vapor flow entering the pulse combustion chamber (4b). 8. The pulse combustion dryer according to any one of claims 1 to 7, wherein the dust separation system comprises a cyclone (10) connected to an outlet (9a) of the drying chamber (9) and to the steam outlet line (13a). 9. The pulse combustion dryer according to any one of claims 1 to 7, wherein the dust separation system comprises a bag filter (11) connected to an outlet (9a) of the drying chamber (9) and to the steam outlet line (13a). 10. The pulse combustion dryer according to any one of claims 1 to 7, wherein the dust separation system comprises a cyclone (10) connected to an outlet (9a) of the drying chamber (9) and a bag filter (11) connected to the cyclone (10) and to the steam outlet line (13a). 11. The pulse combustion dryer according to any one of claims 1 to 7, wherein the dust separation system comprises a cyclone (10) connected to an outlet (9a) of the drying chamber (9) and a bag filter (11) connected to the cyclone (10) and to the steam outlet line (13a). 12. The pulse combustion dryer according to any one of claims 1 to 7, wherein the dust separation system comprises a cyclone (10) connectable to an outlet (9a) of the drying chamber (9) and to the steam outlet line (13a), and a bag filter (11) connectable to the cyclone (10) and to the outlet (9a) of the drying chamber (9) and connected to the steam outlet line (13a). 13. The pulse combustion dryer according to any one of the preceding claims, wherein the steam outlet line (13a) comprises a filter, preferably an activated carbon filter, for removing volatile organic compounds from the water vapor.