Submerged combustion furnace for producing frit and method for producing frit

Abstract

The present invention relates to a submerged combustion furnace for melting ceramic frits by means of a submerged combustion process, said furnace comprising at least one control loop with feedback of the overall weight regulating at least one process variable of the furnace for producing ceramic frit. The invention also relates to a regulating method for a submerged combustion furnace having these features, whereby obtaining a batch production of a ceramic frit having certain characteristics. The regulating method is implemented in the system by means of regulating process variables relating to the production of molten material during production.

Claims

1. A submerged combustion furnace for melting ceramic frits comprising: at least one submerged combustion burner, at least one furnace force measurement system to determine the overall weight of the submerged combustion furnace, at least one valve for regulating at least one process variable of the submerged combustion furnace, said process variable being a parameter of the submerged combustion furnace suitable for changing the conditions of the melting of ceramic frits, at least one control loop with feedback of the overall weight, wherein the at least one control loop is adapted for regulating the overall weight by acting on the at least one valve for regulating the at least one process variable of the submerged combustion furnace, characterized in that the at least one valve is configured to: regulate the at least one process variable, the at least one process variable being a fusion energy supply to the submerged combustion furnace, and keep constant the raw material feed into the submerged combustion furnace.

2. The submerged combustion furnace for melting ceramic frits according to claim 1, characterized in that the at least one valve is configured to: keep constant the molten material outlet from the submerged combustion furnace.

3. The submerged combustion furnace for melting ceramic frits according to claim 1, characterized in that the submerged combustion furnace comprises the at least one control loop and two additional control loops, the control loops being adapted for regulating the overall weight by means of the furnace force measurement, acting on the at least one process variable and two additional process variables, raw material feed into the submerged combustion furnace, molten material outlet from the submerged combustion furnace, or the fusion energy supply.

4. The submerged combustion furnace for melting ceramic frits according to claim 1, characterized in that the at least one furnace force measurement system measures weight or deformation.

5. The submerged combustion furnace for melting ceramic frits according to claim 1, further comprising a second valve having a section that can be regulated, the second valve regulating the material outlet.

6. The submerged combustion furnace for melting ceramic frits according to claim 1, characterized in that the submerged combustion furnace comprises at least one auxiliary burner located in the upper wall or ceiling of the submerged combustion furnace.

7. The submerged combustion furnace for melting frits according to claim 1, characterized in that the chamber of the submerged combustion furnace comprises refractory or cooled metal partitions.

8. The submerged combustion furnace for melting ceramic frits according to claim 1, characterized in that the submerged combustion furnace comprises measurement means for measuring an incoming flow rate, outgoing flow rate or both.

9. A regulating method for regulating continuous batch production in a submerged combustion furnace according to claim 1, the method comprising the steps of: a) starting up the submerged combustion furnace, b) pre-loading the submerged combustion furnace with an amount of raw material equal to a weight or tare, c) maintaining said raw material of weight until it melts and a molten homogenous bath is obtained, d) providing a setpoint value of weight of molten material to be produced, e) continuously feeding raw material into the submerged combustion furnace up to a value of weight equal to the sum of the tare plus the setpoint value of weight f) regulating production by means of the control loop until reaching an optimal melting point, optimal molten material being obtained, g) discharging molten material by means of the molten material outlet system, simultaneously maintaining the raw material feed, and h) ending the discharging of the molten material from the submerged combustion furnace when the value of the batch is reached.

10. The regulating method for regulating batch production in a submerged combustion furnace according to claim 9, further comprising the steps of: i) ending the feeding of the raw material into the submerged combustion furnace, j) discharging the molten material corresponding to the weight of the tare by means of the outlet system.

11. The regulating method for regulating batch production in a submerged combustion furnace according to claim 10, further comprising the steps of: k) switching off the submerged combustion furnace.

Description

DESCRIPTION OF THE DRAWINGS

(1) The foregoing and other features and advantages of the invention will become clearer from the following detailed description of a preferred embodiment given solely by way of illustrative and non-limiting example in reference to the attached drawings.

(2) FIG. 1 generally shows a submerged combustion furnace regulated by means of a control loop according to a first embodiment.

(3) FIG. 2 shows a control loop adapted for regulating the submerged combustion furnace through the molten material outlet.

(4) FIG. 3 shows a control loop adapted for regulating the submerged combustion furnace through the raw material inlet.

(5) FIG. 4 shows a control loop adapted for regulating the submerged combustion furnace through the fusion energy supply.

(6) FIG. 5 shows a control loop adapted for regulating the submerged combustion furnace through the molten material outlet, the raw material inlet and the fusion energy supply.

(7) FIG. 6a shows a first part of the continuous ceramic frit batch production process.

(8) FIG. 6b shows a second part of the continuous ceramic frit batch production process.

(9) FIG. 6c shows a third part of the continuous ceramic frit batch production process.

(10) FIG. 6d shows a fourth part of the continuous ceramic frit batch production process.

DETAILED DESCRIPTION OF THE INVENTION

(11) FIG. 1 shows a general depiction of the submerged combustion furnace (SCF) of the invention according to a first embodiment thereof.

(12) Said furnace comprises a series of submerged combustion burners (1) located both at the base of the chamber of the furnace (SCF) and in other positions that allow locating them within the molten bath.

(13) In a particular embodiment, these burners (1) can also be located in the ceiling (C) of the chamber and be lowered by means of an extendable shaft until being submerged in the molten bath.

(14) This particular embodiment of the submerged combustion furnace (SCF) also comprises a force measurement system (2) measuring the overall weight (OW) of the furnace, which includes the weight of the furnace FW together with the weight of molten material inside the chamber MW.

(15) The furnace has a molten material outlet (3), controlled by means of a valve the section of which can be regulated, through which the molten material (MM) that is produced is discharged from the chamber of the furnace. Said outlet (3) is regulated through the control loop (6) provided with feedback about the overall weight (OW) obtained through the force measurement system (2), in this case a weight measurement system.

(16) The furnace also has a raw material inlet (4) controlled by means of any system that allows the progressive inlet of material necessary for ceramic frit batch (B) production. Said inlet is regulated through the control loop (6) provided with feedback about the overall weight (OW) obtained through the force measurement system (2), in this case a weight measurement system.

(17) The furnace furthermore has a fusion energy supply (5) controlled by means of any system which allows the entrance of both fuel and combustion agent into the chamber of the furnace (SCF), which are necessary for ceramic frit batch (B) production. Said entrance is regulated through the control loop (6) provided with feedback about the overall weight (OW) obtained through the force measurement system (2), in this case a weight measurement system.

(18) In a particular embodiment, the chamber of the furnace also has an auxiliary burner (AB) located in the ceiling (C) which acts both during furnace startup and after that point, such that complete combustion takes place in the chamber.

(19) This submerged combustion furnace (SCF) can be regulated through the control loop (6) in different ways and through different process variables (X), such as those already mentioned.

(20) In a particular embodiment, the chamber of the furnace (SCF) also has a cooling system in the walls of said chamber formed by metal panels (METP) that are cooled by means of a coolant circulation system (not depicted).

(21) FIG. 2 shows a control loop (6) regulating ceramic frit production by means of the overall weight (OW). The overall weight (OW) acts both as an inlet variable and an outlet variable, as well as a feedback variable of the control loop (6), the purpose of which is to equal the weight at the inlet of the furnace with the previously defined setpoint value (Vw), such that molten material (MM) production is kept controlled through the level of said molten material bath inside the chamber of the furnace.

(22) Regulation is performed in this case on the regulated molten material outlet (3) system, and the data necessary for controlling and regulating by means of the control loop (6) is taken through the force measurement system (2), in this case a weight measurement system. The process variable (X) that is regulated is therefore the molten material (MM) outlet from the chamber of the furnace (SCF).

(23) FIG. 3 shows a control loop (6) regulating ceramic frit production by means of the overall weight (OW). The overall weight (OW) acts both as an inlet variable and an outlet variable, as well as a feedback variable of the control loop (6), the purpose of which is to equal the weight at the inlet of the furnace with the previously defined setpoint value (Vw), such that molten material (MM) production is kept controlled through the level of said molten material bath inside the chamber of the furnace.

(24) Regulation is performed in this case on the regulated raw material inlet (4) system, and the data necessary for controlling and regulating by means of the control loop (6) is taken through the force measurement system (2), in this case a weight measurement system. The regulated process variable (X) is therefore the raw material (RM) inlet of the chamber of the furnace (SCF).

(25) FIG. 4 shows a control loop (6) regulating ceramic frit production by means of the overall weight (OW). The overall weight (OW) acts both as an inlet variable and an outlet variable, as well as a feedback variable of the control loop, the purpose of which is to equal the weight at the inlet of the furnace with the previously defined setpoint value (Vw), such that molten material (MM) production is kept controlled through the level of said molten material bath inside the chamber of the furnace.

(26) Regulation is performed in this case on the fusion energy inlet (5) system, and the data necessary for controlling and regulating by means of the control loop (6) is taken through the force measurement system (2), in this case a weight measurement system. The regulated process variable (X) is therefore the fusion energy supply in the chamber of the furnace (SCF).

(27) FIG. 5 shows a multivariable control loop (6, 6, 6) regulating ceramic frit production by means of the overall weight (OW). The overall weight (OW) acts both as an inlet variable and an outlet variable, as well as a feedback variable of the control loop (6, 6, 6), the purpose of which is to equal the weight at the inlet of the furnace with the previously defined setpoint value (Vw), such that molten material (MM) production is kept controlled through the level of said molten material bath.

(28) Regulation is performed in this case on the fusion energy inlet (5) system, on the regulated molten material (MM) outlet (3) system and on the regulated raw material (RM) feed (4) system. Again, the data necessary for controlling and regulating by means of the control loop (6, 6, 6) is taken through the force measurement system (2), in this case a weight measurement system.

(29) In addition, the invention also relates to a continuous ceramic frit production method by means of a submerged combustion furnace, as described below based on FIGS. 6a-6d.

(30) FIG. 6a shows the pre-loading of the furnace (SCF) with a raw material (RM) weight equivalent to the tare (W1), entering the chamber of the furnace through the regulated raw material (RM) feed (4) system. The pre-loading of the tare (W1) allows starting up the furnace and obtaining the homogenous molten bath, which allows complete combustion given that the submerged combustion burners (1) have been covered.

(31) FIG. 6b shows how after the pre-loading of the tare (W1) in the chamber of the submerged combustion furnace (SCF), the chamber of the furnace (SCF) is loaded with a setpoint value of weight (Vw) of molten material (MM) to be produced, while the continuous process of feeding raw material (RM) through the raw material (RM) feed (4) system is maintained.

(32) The overall weight of the furnace (OW) must have a value equal to the sum of the weight of the system FW, of the tare (W1) and of the setpoint value (Vw) of molten material (MM).

(33) This is achieved by means of regulating through the control loop (6), which keeps the molten material outlet (3) closed, whereas it allows a raw material feed (4) to remain open until achieving the value of overall weight (OW) that is optimal for ceramic frit production. The fusion energy supply (5) is also regulated to allow melting the raw material (RM) onto the homogenous molten bath.

(34) FIG. 6c shows an intermediate step of continuous ceramic frit production where the furnace (SCF) is constantly fed (4) while at the same time molten material (MM) forming the batch (B) that is produced is extracted through the outlet (3). Both the outlet (3) and the inlet (4) from/into the chamber of the furnace are regulated by the control loop (6) at the same time as the fusion energy supply (5).

(35) This regulation allows obtaining an optimal melting point (OMP) which allows ceramic frit batch (B) production with suitable quality in an optimal time.

(36) FIG. 6d shows the final step of the continuous ceramic frit production method, where discharge through the molten material (MM) outlet (3) system begins until obtaining the total amount of ceramic frit making up the desired batch (B).