ES1276744U - HIGH EFFICIENCY HEAT RECOVERY SYSTEM FOR CERAMIC FRIT AND SIMILAR FURNACES (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

High efficiency heat recovery system for ceramic frit furnaces and the like, characterized in that it is made up of: a- A low-flow recuperator (1) of the countercurrent type, formed by an air inlet from the low-flow recuperator (1.1) and an air outlet from the low recuperator (1.10) connected to each other by a longitudinal shell (1.2), in position vertical, which houses low temperature tubes (1.3), intervened by a series of baffles (1.7), arranged alternately, having provided that its lower part is a low heat recovery smoke inlet (1.9) and its upper part a low recovery smoke outlet (1.6), together with the cleaning air injectors (1.4) and its compressed air boiler (1.5), the equipment being externally heat-insulated (1.8). b- A high-flow recuperator (2) of the countercurrent type, in series with the low-flow recuperator (1), formed by an air inlet of the high-flow recuperator (2.1), joined to the air outlet of the low-flow recuperator (1.10) by means of a heat-insulated conduit, and an air outlet from the high-pressure recuperator (2.10), both connected to two annular plenums; the inlet plenum (2.2) and the outlet plenum (2.8), having provided that both plenums are connected by a series of high temperature tubes (2.5), made of ceramic material, in a vertical arrangement and in the shape of a cage, while that the union between the high temperature tubes (2.5) and the plenums is carried out by means of the closing supports (2.3), which are removable and watertight, with the particularity that the assembly is internally lined by the refractory lining (2.6) and this, in turn, by an insulating lining (2.7), while at the bottom of the high-pressure recuperator (2) there is the smoke inlet of the high-pressure recuperator (2.9) and, at the top, the smoke outlet of the discharge recuperator (2.4). (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

HIGH EFFICIENCY HEAT RECOVERY SYSTEM FOR

CERAMIC AND SIMILAR FRIT OVENS

TECHNICAL SECTOR

The present invention belongs to the ceramic frit sector and within this sector more specifically to melting furnaces with air / gas or air / fuel-oil technology, which are used for the production of frits.

The present invention refers to a high efficiency heat recovery system, which has been specially designed for frit furnaces in the ceramic industry, but which is also used in any other field in which there is an evacuation of fumes up to a temperature of approximately 1400 ° C, such as the sodium silicate or glass industry among others. This temperature is reached thanks to the combustion equipment, where the oxidation of the fuel with the oxygen in the air (oxidizer) takes place.

The object of the invention is to increase the temperature of the air (oxidizer) with respect to conventional recovery systems in order to reduce fuel consumption, increasing the efficiency of the assembly and thus favoring the reduction of greenhouse gases.

BACKGROUND OF THE INVENTION

At present, heat recuperators are already known in the aforementioned sector, being intended to be coupled to the smoke evacuation conduit, these recuperators are known in the industry for being of the "double-jacket radiation heat recuperator" type. The most important characteristic that differentiates these traditional recuperators from the equipment object of this invention is that the new heat recovery system combines two countercurrent heat recuperators of the shell type and tubes specifically designed for the thermodynamic conditions of the intervening currents. to traditional equipment, they present a configuration of only one exchanger, either in down-current, or counter-current.

In this way, air temperatures (oxidizer) around 1000 ° C are achieved compared to the approximately 600-800 ° C that are usually obtained in equipment with single recuperator systems.

It is of great interest to introduce the air (oxidizer) into the burner at the highest possible temperature since, in this way, the temperature of the flame is increased and therefore we increase the transfer capacity towards the product to be melted, thus reducing the Fuel consumption around 20% compared to traditional down-current recuperators and 10% compared to countercurrent recuperators.

A consequence of this high temperature recovery system is that the temperature in the lower zone of the recuperator becomes very high, therefore it is necessary to use ceramic materials with a low coefficient of expansion, with good resistance to oxidation. and to corrosion and, all this, at high temperatures, of the order of 1100 ° C

EXPLANATION OF THE INVENTION

The heat recovery unit of the invention itself solves the need to obtain the air (oxidizer) at the highest possible temperature prior to its entry into the combustion equipment, allowing optimal use of the residual energy contained in the fumes produced after combustion. At the same time, this equipment must be able to absorb the expansions suffered by the materials at such temperatures, on the other hand, it must present resistance to possible corrosion and / or abrasion produced by the particles that accompany the fumes.

For this, and more specifically, the heat recovery system is made up of two countercurrent heat recovery units arranged in series. In order to easily differentiate both equipment individually, we will call them from now on in this document as: "low heat recuperator" and "high heat recuperator" referring to the average temperature in which each of them works; high or low. The low heat recuperator (1) located in its upper part preheats the combustion air from the ambient temperature up to about 600-800 ° C. To later raise this temperature again to 900-1000 ° C by means of the high-pressure recuperator (2), located in the lower part of the first recuperator, thus forming a system of two countercurrent recuperators arranged countercurrently to each other, an ideal configuration for preheating the air at the highest possible temperature.

The low heat recuperator (1) is made up of the low heat recuperator air inlet (1.1) and an air outlet of the low heat recuperator (1.10). Both mouths are connected to each other by means of a longitudinal shell (1.2) arranged vertically, which houses a bundle of low-temperature tubes (1.3), to which a series of deflectors (1.7) is added, arranged in an alternate distribution , responsible for hindering the passage of combustion air, thus favoring the transfer by convection. The fumes produced in combustion run through the interior of the low temperature tubes (1.3), which enter the low temperature recuperator through the flue gas inlet (1.9) and exit through the upper part or the low temperature recuperator fumes outlet (1.6 ). In order to prevent the particles transported within the combustion gases from forming incrustations and adhesions on the inside of the tubes, just before leaving the low-pressure recuperator (1), some cleaning air injectors (1.4) the low temperature tubes (1.3) shoot a pulse of air at regular intervals from the compressed air cylinder (1.5). The whole set is covered by a layer of insulation (1.8), using an insulating material such as rock wool, ceramic fiber, or microporous material, depending on the temperature of the area to be insulated.

The air that leaves the recuperator through the low recuperator air outlet (1.10) passes to a heat-insulated duct that directs it to the air inlet of the high recuperator (2.1).

On the other hand, the high-flow recuperator (2) is formed, like the low-flow recuperator (1), by two mouths. Both mouths are connected to two annular plenums for an effective distribution of high recovery air. The air passes through the mouth at the low recovery air inlet (2.1) to the inlet plenum (2.2) and, for its part, the outlet plenum (2.8) to the high recovery air outlet ( 2.10) Between the inlet and outlet plenums, the hot air flows axially through the high-temperature tubes (2.5) made of ceramic material in a vertical arrangement. Said high temperature tubes (2.5) are held both by the upper part and the lower part by some closing brackets (2.3), these are in charge of ensuring the tightness in both plenums, and have the peculiarity that they are removable, thus facilitating the change of tubes in case of breakage or wear without having to disassemble the complete recovery system.

On the other hand, with regard to the fumes, they enter at their maximum temperature, approximately 1150-1250 ° C, through the lower part where the smoke inlet to the high-pressure recuperator is located (2.9). They do it in an axial direction and, as they pass through the interior of the high-temperature recuperator (2), they give up heat, mainly due to the radiation phenomenon, to the high-temperature tubes (2.5) and the refractory lining (2.6) and, the latter, also in turn, yields it to the high-temperature tubes again (2.5). Finally, the fumes exit through the high recuperator flue outlet (2.4), at about 900-1100 ° C, leaving the high recuperator (2) to enter the low recuperator (1), thus continuing the preheating process of the combustion air object of this invention.

Structurally, the integrity of the heat recovery system is defined by the peculiarities of each one of the heat recovery units. The low heat recovery unit (1), being metallic in nature, is suspended from its upper part, that is, the equipment behaves under traction, expanding vertically and downwards, through the heating process, compressing up to the starting point during the cooling process. On the other hand, with regard to the discharge recuperator (2) of a ceramic nature, it is supported on its lower part since, structurally, it is constituted by the refractory lining (2.6), which works under compression, that is, during During the heating process the recuperator expands vertically and upwards and during the cooling process the discharge recuperator (2) is compressed, recovering its initial shape. In this way, we can simplify that both recuperators move closer to each other as the working temperature increases.

To minimize heat losses to the outside, the low heat recovery unit (1) has a heat-insulating layer (1.8), made up of microporous insulation, which withstands temperatures of up to 1000 ° C, without prejudice to other similar materials, located between the shell (1.2) and the outer metal liner. On the other hand, and for the same purpose, the discharge recuperator (2) has an insulating coating (2.7), made up of a combination of ceramic fibers (up to about 1300 ° C) and microporous material (up to about 1000 ° C) , also without prejudice to the use of other materials with similar characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to illustrate the explanation that will follow, we attach to the present specification a sheet of drawings, in which, in three unique figures, the essence of the present invention is represented, by way of example and without limitation, and in which the following can be observed:

Figure 1 shows a sectional elevation view of the heat recovery system, where you can see the air inlet of the low heat recuperator (1.1) in the upper part of the equipment, together with the smoke outlet of the low heat recuperator ( 1.6) and, in its lower part, the air outlet of the discharge recuperator (2.10), together with the smoke inlet of the discharge recuperator (2.9), suggesting that these are two countercurrent recuperators presenting their set of globally, a configuration also in countercurrent, this set being the object of this invention

Figure 2 shows a plan view of the main section of the low temperature recuperator (1), where the radial air inlet of the low temperature recuperator (1.1) and the arrangement of the low temperature tube bundle (1.3) can be seen, together with a deflector (1.7), both enveloped by the shell (1.2) which, in turn, is externally enveloped by the lagging (1.8)

Figure 3 shows a plan view of the main section of the high temperature recuperator (2), where you can see the radial air outlet of the high temperature recuperator (2.10), the cage arrangement of the high temperature tubes (2.5) and the refractory lining (2.6) which is surrounded, in turn, by the insulating lining (2.7)

In the aforementioned figures, the following constituent elements can be highlighted: 1. Loss recuperator

1.1- Low recuperator air inlet

1.2- Breastplate

1.3- Low temperature tubes

1.4- Cleaning air injectors

1.5- Compressed air cylinder

1.6- Low heat recovery smoke outlet

1.7- Deflectors

1.8- Heat insulation

1.9- Low heat recovery fume inlet

1.10- Low recuperator air outlet

2. Discharge recuperator

2.1- High recuperator air inlet

2.2- Inlet plenum

2.3- Closing supports

2.4- Smoke outlet from the discharge recuperator

2.5- High temperature tubes

2.6- Refractory lining

2.7- Insulating coating

2.8- Outlet plenum

2.9- Smoke inlet of the discharge recuperator

2.10- High recuperator air outlet

PREFERRED EMBODIMENT OF THE INVENTION

In view of the figures outlined, it can be seen how the heat recovery system that the invention proposes is made up of two countercurrent recuperators in series, therefore the set also formed in countercurrent function. The low recuperator (1) is located in the upper part and the high recuperator (2) in the lower part, understanding as high and low the temperature average at which each of them work.

The low-pressure recuperator (1) is made up of an air inlet from the low-pressure recuperator (1.1) and an air outlet from the low-pressure recuperator (1.10), connected to each other by a longitudinal shell (1.2), in a vertical position, which it houses a bundle of low temperature tubes (1.3), intervened by a series of baffles (1.7) arranged alternately. In its lower part, we find the smoke inlet of the low heat recovery unit (1.9) and, in its upper part, the smoke outlet of the low heat recovery unit (1.6), together with the cleaning air injectors (1.4) and its boiler compressed air (1.5). Externally, the equipment is covered by a layer of insulation (1.8).

The air outlet of the low recuperator (1.10) and the air inlet of the high recuperator (2.1) are united by means of a heat-insulated duct.

The high recuperator (2) is formed by an air inlet from the high recuperator (2.1) and a high recuperator air outlet (2.10), both connected to two annular plenums; the inlet plenum (2.2) and the outlet plenum (2.8). Both plenums are connected by a series of high-temperature tubes (2.5), made of ceramic material, in a vertical cage-shaped arrangement. The union between the high temperature tubes (2.5) and the plenums (2.2 and 2.8) is carried out by means of the closing brackets (2.3), which are removable and watertight. The assembly is internally lined by the refractory lining (2.6) and this, in turn, by an insulating lining (2.7). At the bottom of the discharge recuperator (2) we have the flue gas inlet of the discharge recuperator (2.9) and, by its upper part, the flue gas outlet of the discharge recuperator (2.4).

Claims (3)

1. - High efficiency heat recovery system for ceramic frit furnaces and similar, characterized in that it is made up of: a- A low-flow recuperator (1) of the countercurrent type, formed by an air inlet from the low-flow recuperator (1.1) and an air outlet from the low recuperator (1.10) connected to each other by a longitudinal shell (1.2), in position vertical, which houses low temperature tubes (1.3), intervened by a series of deflectors (1.7), arranged alternately, having provided that its lower part is a low heat recovery flue (1.9) and its upper part a low recovery smoke outlet (1.6), together with the cleaning air injectors (1.4) and its compressed air boiler (1.5), the equipment being externally heat-insulated (1.8). b- A high-flow recuperator (2) of the countercurrent type, in series with the low-flow recuperator (1), formed by an air inlet of the high-flow recuperator (2.1), joined to the air outlet of the low-flow recuperator (1.10 ) by means of a heat-insulated conduit, and an air outlet from the high-pressure recuperator (2.10), both connected to two annular plenums; the inlet plenum (2.2) and the outlet plenum (2.8), having provided that both plenums are connected by a series of high temperature tubes (2.5), made of ceramic material, in a vertical arrangement and in the shape of a cage, while that the union between the high temperature tubes (2.5) and the plenums is carried out by means of the closing supports (2.3), which are removable and watertight, with the particularity that the assembly is internally lined by the refractory lining ( 2.6) and this, in turn, by an insulating coating (2.7), while at the bottom of the high-pressure recuperator (2) there is the smoke inlet of the high-pressure recuperator (2.9) and, at the top, the flue gas outlet of the discharge recuperator (2.4) 2. - High efficiency heat recovery system for ceramic frit furnaces and the like according to claim 1 characterized in that the low heat recovery (1) has a cleaning system using regular pulses of compressed air, consisting of cleaning air injectors (1.4), connected to a compressed air cylinder (1.5). 3.- High efficiency heat recovery system for ceramic frit furnaces and the like according to claims 1 and 2 characterized in that the high temperature recuperator (2) has an easy disassembly system for high temperature tubes (2.5 ), by means of the closing supports (2.3), located in the inlet plenum (2.2) and in the outlet plenum (2.3).