WO2019097497A1

WO2019097497A1 - Plant for burners in an industrial oven, and oven provided with such plant

Info

Publication number: WO2019097497A1
Application number: PCT/IB2018/059125
Authority: WO
Inventors: Corradini MARIO
Original assignee: Ancora SpA
Current assignee: Ancora SpA
Priority date: 2017-11-20
Filing date: 2018-11-20
Publication date: 2019-05-23
Anticipated expiration: 2020-05-20

Abstract

A plant (1) for burners in an industrial oven (2), formed by a predetermined number of oven modules (3), each of the modules (3) being provided with a certain number of burners (4), each burner (4) being connected to a first pipe (9) which provides the combustive agent, or primary air, at a specific pressure, and being connected to a second pipe (8) which provides the fuel, for example natural gas or other types of gaseous or liquid fuels; the plant (1) comprises a generator (10) of additive gas, which is introduced through a third pipe (14) into the first pipe (9) of the combustive agent near each burner (4), and/or said additive gas is introduced through a fourth pipe (20) directly into each burner (4).

Description

“PLANT FOR BURNERS IN AN INDUSTRIAL OVEN, AND OVEN PROVIDED

WITH SUCH PLANT”

TECHNICAL FIELD OF THE INVENTION

The present invention refers to a plant for burners in an industrial oven and to an oven provided with such plant.

More particularly, the present invention refers to a plant of improved type for burners in industrial ovens for firing ceramic products such as ceramic tiles, sanitary bathroom fixtures and the like, as well as the relative oven provided with such plant.

STATE OF THE ART

In the field of industrial ovens, with particular but not exclusive reference to the ovens for firing products such as ceramic tiles, sanitary fixtures, and the like, the plants used comprise burners which are connected to a plant for feeding the fuel and to a duct for feeding the air, i.e. the combustive agent for burning the fuel.

In general, the burners of this type comprise means for supplying the fuel and a series of openings which communicate with the air feeding duct in order to send the air towards the combustion zone.

The burners are applied to the industrial oven in various ways as a function of the different zones and of the treatments to be carried out on the products, and the oven can be divided into modules that are repeated a certain number of times.

Each zone and each module will have different treatment temperatures according to the requirements of the product to be treated, being composite ceramic products and hence necessarily subject to different thermal treatments in order to obtain the best condition of the finished product.

The various ceramic pastes contain organic substances that must be eliminated from the final product, maintaining and regulating the temperatures of the treatment zones.

In order for the organic substances to be able to exit from the pastes without deteriorating the quality of the superimposed enamels, in a manner so as to obtain uniform products with optimal quality of the product and of the final production, thermal gradients must be maintained that are consistent with the critical states of the paste and of the enamels employed.

For these thermal treatments, it is necessary to have high thermal energy, hence considerable energy costs in relation to the obtained product surface areas.

Unfortunately, the energy costs are not always proportional to the product quality, creating discards and increasing the production costs and environmental problems due to the energy consumption.

High thermal energy is necessary for obtaining high-quality products and for obtaining the transformation of the alpha quartz to beta quartz and vice versa with long and specific heating times in relation to the type of product to be obtained

The need for long treatment times determines a considerable waste of fuel, and however if these long times are not maintained there can be considerable production waste.

Presently, an industrial oven in the ceramic field for the thermal treatment of ceramic manufactured items, with an average production of 20,000 square meters of product per day, requires about 2100 kJ per kg of fired product mass.

Due to such high energy consumptions per unit of product mass, it is therefore very important to find ways to reduce the percentage of consumptions, so that these percentage reductions lead to high savings in terms of energy and costs in absolute value.

There is therefore the need to find alternatives for reducing the energy and environmental costs, improving the operation of the burners of the present type, especially with regard to the regulation stability and the cost of operation.

OBJECTS OF THE INVENTION

Hence, the main object of the present invention is to improve the state of the art in the field of plants for burners in industrial ovens.

In the scope of such task, one object of the present invention is to provide a plant for burners in an industrial oven which improves the process of combustion and the efficiency of the burners of known type.

Another object of the present invention is to provide a plant for burners in an industrial oven which can be easily employed also in pre-existing industrial ovens and in tunnel ovens as well as in closed ovens. Another object of the present invention is to provide a plant for burners in an industrial oven which is easy to manufacture, and with competitive costs.

Another object of the present invention is to provide a plant for burners in an industrial oven with lower emissions, in particular of NOx and CO with respect to the conventional plants.

These and still other objects of the present invention are achieved by a plant for burners in an industrial oven according to claim 1.

The dependent claims refer to preferred and advantageous embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will be more evident from the detailed description of a non-exclusive embodiment of a plant for burners in an industrial oven, according to the present invention, given as a non-limiting example, in the enclosed set of drawings in which:

figure 1 is a schematic front view of a plant for burners in an industrial oven according to the present invention;

figure 2 is a detailed view of a detail of the plant for burners in an industrial oven pursuant to the preceding figure;

figure 3 is a schematic front view of another version of a plant for burners in an industrial oven according to the present invention;

figure 4 is a detailed view of a detail of the plant for burners in an industrial oven pursuant to the preceding figure;

figure 5 is a schematic front view of a further version of plant for burners in an industrial oven according to the present invention;

figure 6 is a detailed view of a detail of the plant for burners in an industrial oven pursuant to the preceding figure;

figure 7 is a top schematic view of several common parts of the plants for burners in an industrial oven illustrated in the preceding figures; and

figures 8 and 9 are respectively slightly top and front views of a component of a plant according to the present invention with generators of additive gas. EMBODIMENTS OF THE INVENTION

In the enclosed figures, several versions of a plant 1 for burners according to the present invention are illustrated; the plant 1 is applied to an industrial oven 2 of which only one module 3 is shown as an example. The number of overall modules 3 is subordinate to the required ceramic product production. The oven 2 can for example be for the production of ceramic tiles, if desired for floors or for the production of sanitary articles, bricks or roof tiles.

According to the embodiment illustrated in the figures, each module 3 comprises eight burners 4 (of which only one is illustrated for the sake of clarity) mounted offset with four on one side and four opposite these on the other side of the module 3; it is clear that in any case there can be any number of burners 4 and the arrangement of such burners 4 can be of any type.

In accordance with the present invention and visible in figures 1, 3, 5 and 7, each burner 4 is connected by means of a first pipe 9 to a first duct 5, e.g. common, if desired ring- shaped, which supplies the combustive agent i.e. the primary combustion air; standard means are provided for regulating and commanding the air that comes from the first combustive agent duct 5.

Each burner 4 is also connected by means of a second pipe 8 to a second duct 6, e.g. common, if desired ring-shaped which provides the fuel, e.g. natural gas, methane or other types of gaseous or liquid fuels.

The second duct 6 for the fuel can be regulated by means of a motorized modulation valve 7 in order to adapt and maintain the temperature of the treatment zone as a function of the requested curves depending on the production technologies.

An important characteristic of the present invention is that the plant 1 comprises at least one generator 10 of additive gas, which is capable of generating a gas, e.g. a mixture of gas and vapor through electrolysis of water.

The generator 10 of additive gas comprises control means 11 which allow regulating the supply of the additive gas as a function of the needs of the burners 4. Such generator 10 operates according to the Mills theory and comprises one or a plurality of cells, each composed of two electrodes, a cathode and an anode, whose charge is periodically reversed at predefined time intervals, such that a first electrode will act alternatively as positive electrode and as negative electrode, while the other or second electrode will act as negative electrode, when the first acts as positive electrode and will act as positive electrode, when the first acts as negative electrode. The electrodes can be formed by means of an inert metal.

Each cell then comprises an electrolyte, e.g. between the two electrodes.

The generator also comprises one or more batteries in electrical communication with the electrodes of the cells.

The mechanism underlying the operation of one such generator provides that the electric current from the battery is passed through the cell or cells, cyclically inverting, as stated above, the charge to the electrodes so as to produce hydrogen and oxygen from the electrolysis and traces of water vapor.

The temperature in the generator 10 can be between about 65°C and 85°C in order to facilitate the formation of the additive gas.

More particularly, during the discharge step, EhO is formed at the anode following the oxidation of OH and reaction with H⁺ and, as a result of the reaction with the nascent water which acts as catalyst, compounds definable as“hydrinos” are formed. The latter, in mixture with the other obtained compounds, form additive gas definable as “hydrogas”. When the hydrinos are formed, energy is liberated that causes various spontaneous electrochemical reactions at both electrodes.

The cell or cells in practice create an additive gas or“hydrogas” starting from water or H₂0, following the migration of the electrons through the external circuit of the cell(s) and a transport of ions to the interior of the electrolyte of the cell itself or of the cells themselves.

In one version of the present invention illustrated in figure 1, the generator 10 introduces the additive gas in the combustive agent, i.e. air, for each burner 4 of the module 3.

For such purpose, the generator 10 has a tube 12 which introduces the additive gas in a third duct 13, e.g. common, if desired ring-shaped which is in turn connected to each burner 4 by means of a third pipe 14 which is joined to the first pipe 9 of the primary air with a Y-shaped joint 15.

The third duct 13 can also comprise a centrifugal fan 16 that allows balancing the pressure of the primary air attained by a relative centrifugal fan 17.

In this manner, the primary air is mixed with a percentage of additive gas which can be regulated and varied according to the operating needs of the oven 2.

For an improved division of the additive gas within the common ring-shaped third duct 13, the tube 12 that introduces the additive gas in the combustive agent is positioned in the central suction zone of the centrifugal fan 16 of the third duct 13.

The plant can also be provided with a system for detecting and controlling the levels of the combustion in the combustion chamber of the oven 2. This detection and control system could be used for regulating the flow rate of the additive gas generator 10 and/or of the fan for feeding combustive air in the first duct 5.

Experimental tests have demonstrated that an improved regulation stability of the burner 4 is obtained, since the motorized modulation valve 7 for the fuel is regulated over nearly constant opening values and without regulation oscillations.

In addition, a decrease of fuel consumptions was also verified, given the same other operating conditions, temperature, supplied heat, etcetera.

Moreover, due to the introduction of additive gas, it is possible to reduce the emissions, in particular of NOx and CO, the latter also able to be reduced to about 0. In substance, the additive gas removes all or most of the pollutant substances.

Figure 3 illustrates a first variant of the plant 1.

In this case, the generator 10 of additive gas introduces the additive gas in the fuel.

For such purpose, the generator 10 has a tube 18 for introducing the additive gas in a fourth duct 19, e.g. common, if desired ring-shaped, which is in turn directly connected to each burner 4 by means of a fourth pipe 20.

As is visible more in detail in figure 4, the additive gas passes into the duct 20 and enters into the burner through a nozzle 21, and the mixture of the additive gas with the fuel only occurs within the burner 4.

All the other components of the plant, which have the same reference numbers of the plant illustrated in the version of figure 1, remain substantially unaltered. Figure 5 illustrates a second variant of the plant 1.

In this case, the additive gas generator 10 introduces the additive gas both in the combustive agent and in the fuel or individually, i.e. only in the combustive agent, or only in the fuel.

In addition, the generator 10 has a tube 18 for introducing the additive gas in a common ring-shaped fourth duct 19 which is in turn directly connected to each burner 4 by means of a fourth pipe 20.

This embodiment of the plant 1 therefore constitutes a combination of the two embodiments of the preceding figures 1 and 3.

Greater possibility to regulate the introduction of the additive gas into the burner 4 is thus attained. The generator 10 also has two respective regulation means 11 for the common ring-shaped third duct 13 and for the common ring-shaped fourth duct 19. Figure 7 schematically illustrates a top view of part of the plant 1 in the version of figure 1, in which the shape and distribution of the common ring-shaped first duct 5 can be observed with the respective eight pipes 9, which supply the combustive agent to the eight burners 4 (not illustrated) of the module 3 of the oven 2.

In addition, the shape and distribution of the common ring-shaped third duct 13 are visible, the latter having the respective eight pipes 14 which supply the additive gas to the eight burners 4.

With reference now to figures 8 and 9, a plurality of generators 10 is illustrated, e.g. ten, for a plant according to the present invention, e.g. for a plant with 8 burners, and such generators 10 are mounted in a furniture piece 22 below a water tank 23, if desired of distilled water, e.g. only one tank for all the generators. Then, a battery 24 or a plurality of batteries 24 is provided, if desired in the same furniture piece 22, for serving the generators 10.

Then, starting from one side of the furniture piece 22, a tube 12 or 18 is extended that is in fluid communication with the outlet of the generators 10 and set to convey additive gas as indicated above.

Therefore, due to the present invention, it is possible to considerably reduce the fuel consumptions as well as the emissions of pollutant substances, in particular of NOx and CO.

The invention thus conceived is susceptible of numerous modifications and variations, all falling within the scope of the inventive concept.

In addition, all details can be substituted by other technically equivalent elements.

In practice, the materials used, as well as the contingent shapes and sizes, can be of any type in accordance with the requirements, without departing from the protective scope of the following claims.

Claims

1. Plant (1) for burners in an industrial oven (2), said oven (2) comprising a predetermined number of oven modules (3), each of said modules (3) being provided with a certain number of burners (4), each burner (4) being connected to a first pipe (9) which supplies the combustive agent, or primary air, at a given pressure, and being connected to a second pipe (8) which supplies the fuel, for example natural gas or other types of gaseous or liquid fuels, the plant (1) being characterized in that it comprises at least one generator (10) of additive gas and in that said additive gas is introduced through a third pipe (14) in the first pipe (9) of the combustive agent near each burner (4), and/or said additive gas is introduced through a fourth pipe (20) directly into each burner (4).

2. Plant (1) according to claim 1, wherein said generator (10) of additive gas comprises control means (11) for regulating the supply of the additive gas according to the needs of the burners (4).

3. Plant (1) according to claims 1 or 2, wherein said third pipe (14) joins the first pipe (9) through a joint (15).

4. Plant (1) according to any one of the preceding claims, comprising a third common ring-shaped duct (13) within which said additive gas from said generator (10) is fed, said third duct (13) being connected to each burner (4) through said third pipe (14).

5. Plant (1) according to the previous claim, wherein said third duct (13) comprises a centrifugal fan (16) which allows to balance said pressure of said combustive agent, or primary air.

6. Plant (1) according to any one of the preceding claims, comprising a fourth ring-shaped duct (19) within which said additive gas is introduced from said generator (10), said fourth duct (19) being directly connected to each burner (4) through said fourth pipe (20).

7. Plant (1) according to any one of the preceding claims, wherein said at least one generator (10) generates said additive gas through the electrolysis of water and comprises one or a plurality of cells, each composed of: - two electrodes, whose charge is periodically inverted at predefined time intervals, so that a first electrode will act alternately as a positive electrode and as a negative electrode, while the other or second electrode will act as negative electrode when the first electrode acts as positive electrode and it will act as a positive electrode when the first electrode acts as a negative electrode,

- an electrolyte arranged between the two electrodes, and

- at least one battery in electrical communication with the electrodes of said cell or of said plurality of cells.

8. Plant (1) according to claim 7, wherein the electric current from said at least one battery is passed through the cell or cells cyclically inverting the charge to the electrodes in order to produce hydrogen and oxygen from the electrolysis and traces of water vapour.

9. Plant (1) according to claim 7 or 8, wherein the temperature in the generator (10) is between about 65° C and 85° C.

10. Plant (1) according to any one of the previous claims, comprising a system for detecting and controlling the combustion in the combustion chamber of the oven (2).