A method for melting electric sub-fire full hydrogen and full oxygen float glass

Abstract

The invention discloses a method for melting electric sub-fire full hydrogen and full oxygen float glass, comprising: dividing the glass melting pool into a rod area, a foam area, a hot spot area and a mirror area, setting an electric heating system in each area, and inserting a bubbler system in the mirror area; arranging a bottom-fired heating spray gun system on the breast wall, wherein the hydrogen energy consumption of the hot spot area and the mirror area accounts for more than 35% of the total energy consumption; heating by electric energy, adding mineral fuel at the same time, and heating the above-mentioned pools by a mineral fuel auxiliary electric heating system; adjusting the electric energy heating ratio to more than 60% of the total heating energy, wherein the heating electric energy of the rod area and the foam area is adjusted to more than 40% of the total heating electric energy; separating the melting area from the cooling area. The beneficial effects of the invention are: it can ensure that the longitudinal convection morphology of the glass kiln does not change greatly and the temperature gradient of the glass liquid does not occur, meet the process operation requirements, save energy, reduce the emission of carbon oxides and nitrogen oxides, and has obvious economic and social benefits.

Description

Technical Field

[0001] The invention relates to the technical field of glass manufacturing, in particular to a method for melting electric sub-fire full hydrogen and full oxygen float glass. Background Art

[0002] The main energy-consuming equipment in the float glass production line is the glass melting furnace, which is the facility with the largest energy consumption in the float glass production line. The energy consumption of the glass melting furnace accounts for 93% of the total energy consumption of the float glass production line. Therefore, the key to reducing the energy consumption of float glass production is to improve the energy utilization rate of the glass melting furnace.

[0003] Oxygen combustion technology uses pure oxygen instead of traditional air as the combustion-supporting gas. The use of full oxygen combustion can significantly reduce NO X The emission of oxyfuel can be reduced, the utilization rate of fuel heat can be improved, and the amount of fuel used can be reduced. At the same time, the use of full oxygen combustion can also improve the melting rate and glass melting quality, simplify the structure of the glass melting furnace, greatly reduce the construction cost, and extend the life of the furnace. Some data believe that full oxygen combustion technology will increase the content of hydroxyl and structural water in the glass, affecting the structure and performance of the glass.

[0004] With the rising price of fossil fuels and the gradual decline in electricity prices, the application scope of electric melting technology in furnaces such as container glass, utensil glass, borosilicate glass, float glass, and glass fiber has gradually expanded, and the application of electric melting technology has become more and more extensive.

[0005] Electric melting of float glass is divided into full electric melting, auxiliary electric melting and fire-electric composite melting. Full electric melting is a process in which all batch materials are melted into qualified glass liquid by electric heating; auxiliary electric melting is an auxiliary melting measure to improve the melting capacity of flame melting furnace and the quality of glass liquid by adding extra electric energy through electrodes inserted into the glass liquid; fire-electric composite melting is a melting process that combines fuel flame melting and electric melting, that is, mineral fuel is used to heat the space above the batch materials, and electrodes are used to heat the glass liquid below the batch materials layer.

[0006] Electric-fire composite melting is a melting process that combines fuel flame melting and electric melting. That is, mineral fuel is used to heat the space above the batch material, and electrodes are used to heat the glass liquid below the batch material layer. The difference between electric-fire composite melting technology and electric-assisted melting is that electric-fire composite melting technology is mainly electric melting, supplemented by flame melting, while electric-assisted melting is the opposite.

[0007] Current problems with electric melting technology in float glass production:

[0008] 1. The electric melting ratio is low. The full oxygen melting method will increase the content of hydroxyl and structural water in the glass, affecting the structure and performance of the glass, while the traditional mineral combustion melting will bring environmental pollution problems;

[0009] 2. Unreasonable increase in the proportion of electric melting affects the melting quality. Due to the complex control method of electric melting, unreasonable increase in electric melting may affect the uniformity of the glass, thereby affecting the transparency and color of the glass;

[0010] 3. At present, it is still in the auxiliary electric melting stage, and the utilization of electric energy is not sufficient. The main reason is that there is no reasonable plan for setting electric energy, which makes producers unwilling to take the risk of increasing the electric melting ratio;

[0011] 4. At present, some people have proposed a 300t / d all-electric fused float conceptual design scheme, but the effect is not ideal. The reason is that this scheme is based on the scaled-up version of 120t / d, and the cold top vertical melting process is used. No feasible process measures are proposed for the elimination of microbubbles, so the effect of eliminating microbubbles in the glass solution is not good enough, affecting the quality of the glass. Secondly, no effective control and balancing measures are given for the negative impact of the uniformity of the melting temperature field after the increase of electrode units. Therefore, in general, in the case of large-scale production, it is necessary to increase the melting temperature by increasing the electric energy on a larger scale, which will increase the production cost. Summary of the invention

[0012] The object of the present invention is to provide a method for melting electric sub-fire full hydrogen and full oxygen float glass to solve the technical problems of float glass melting furnace polluting the environment, low electric melting ratio and easy generation of microbubbles in full oxygen combustion electric melting proposed in the above background technology.

[0013] To achieve the above object, the present invention provides the following technical solution: a method for melting electric sub-fire full hydrogen and full oxygen float glass, characterized in that it comprises the following steps:

[0014] The glass melting pool is divided into a rod area, a foam area, a hot spot area and a mirror area according to the form of the glass liquid during melting, and electric heating systems of different powers are arranged at the bottom of the rod area, the foam area, the hot spot area and the mirror area, and a bubbler system is inserted in the mirror area; the rod area, the foam area, the hot spot area and the mirror area are divided into eight units, and a bottom-fired heating spray gun system is arranged on the breast wall, wherein the hydrogen energy consumption of the hot spot area and the mirror area accounts for more than 35% of the total energy consumption;

[0015] The rod area, foam area, hot spot area and mirror area are heated by electric energy, and mineral fuel is added to the above areas, and the above areas are heated by the mineral fuel auxiliary electric heating system;

[0016] The proportion of electric energy heating is adjusted to more than 60% of the total heating energy, wherein the heating electric energy of the rod material area and the foam area is adjusted to more than 40% of the total heating electric energy;

[0017] A neck gate with an automatically adjustable opening is set to separate the melting zone and the cooling zone, reduce the interference of the melting zone on the cooling zone, and optimize the melting process.

[0018] 2. The method for melting electric sub-fire full hydrogen and full oxygen float glass according to claim 1 is characterized in that: the electric heating system with different powers is set according to the daily melting amount ≥500t / d, by determining the total amount of electric melting bottom plug-in energy, determining the electrode partition layout plan, determining the electrode material, calculating the resistance between electrodes, calculating the secondary side voltage, and calculating the current and current density.

[0019] Preferably, the inter-electrode resistance calculation formula is:

[0020]

[0021] Among them, R is the resistance value between electrodes, U is the voltage, I is the current, w is the angular frequency, c is the system capacitance, and L is the system inductance.

[0022] Preferably, the hydrogen fuel accounts for less than or equal to 40% of the mineral fuel, and the glass solution in each zone pool is heated by arranging a bottom-fired gas spray gun.

[0023] Preferably, the ratio of electric energy to mineral fuel energy in the glass melt is not less than 60:40.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention provides a float glass melting method combining electric melting with mineral fuels, and uses electric energy in combination with hydrogen and oxygen for combustion, thereby reducing pollutant emissions from the melting furnace and protecting the environment.

[0026] 2. The present invention realizes the electric melting of sub-fire full hydrogen and full oxygen float glass in a large float glass melting furnace. By setting a neck, it can ensure that the longitudinal convection pattern of the glass furnace does not change significantly and the temperature gradient of the glass liquid does not occur, thereby meeting the process operation requirements.

[0027] 3. The electric-melted sub-fire full hydrogen and full oxygen float glass melting method of the present invention and the melting furnace provided by the present invention can shorten the melting time of the glass solution in the process of glass manufacturing and improve the glass production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a flow chart of a method according to an embodiment of the present invention;

[0029] Figure 2 for Figure 1 Sub-flowchart of ;

[0030] Figure 3It is a top view of the structure of a 500t / d electric melting sub-fire full hydrogen and full oxygen float glass melting furnace according to an embodiment of the present invention;

[0031] Figure 4 The figure is a side view of the structure of a 500t / d electric-melted sub-fire full hydrogen and full oxygen float glass melting furnace according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The present invention provides a technical solution: a method for melting float glass with electric sub-fire full hydrogen and full oxygen. The method is based on the improvement of the shortcomings of the float glass melting process in the prior art, and proposes a new glass melting method by combining the energy combination melting process with electric sub-fire melting. The method for melting float glass with electric sub-fire full hydrogen and full oxygen provided by the present invention uses 60% of electric energy as the main melting, supplemented by hydrogen energy horizontal flame combustion, and an adjustable gate is set at the neck. Different energies are set in different zones for heating and melting. The energy of mineral fuel combustion is assisted by electric energy, which greatly improves the melting efficiency, greatly reduces energy consumption, and greatly reduces carbon dioxide emissions, achieving the beneficial effect of improving the melting quality and efficiency of float glass while protecting the environment.

[0034] The present invention provides a new glass melting method that organically combines full hydrogen and full oxygen combustion in the kiln space and electric melting in the glass liquid. The full hydrogen and full oxygen combustion can greatly reduce CO2 emissions and significantly reduce NOx emissions. In the melting process, hydrogen and oxygen are burned without generating waste gas emissions, thereby reducing air pollution. The high-power pool bottom electric melting technology is adopted to scientifically distribute the fuel load in the flame space and cooperate with the pool bottom bubbler system to form a stable melting system and glass liquid convection field, improve the melting capacity, and the thermal efficiency of electric melting can be as high as 90%.

[0035] Please refer to the photo Figure 1 , Figure 2 , the method comprises the following steps:

[0036] S100: The glass melting pool is divided into a rod area, a foam area, a hot spot area and a mirror area according to the shape of the glass liquid during melting. Electric heating systems with different powers are set at the bottom of the rod area, foam area, hot spot area and mirror area, and a bubbler system is inserted. The eight units set in the rod area, foam area, hot spot area and mirror area are each provided with a number of bottom-fired heating spray gun systems with different heating powers. In the hot spot area and mirror area, the advantage of horizontal flame heating the surface glass liquid is fully utilized, and the hydrogen energy consumption in the hot spot area and mirror area accounts for more than 35% of the total energy consumption.

[0037] In this step, the heating area of ​​the glass melting pool is divided into four levels, namely the first level, the second level, the third level and the fourth level, among which the first level is the rod area (pre-melting area, for preliminary melting of the basic minerals for making glass), the second level is the foam area (raw material melting area), the third level is the hot spot area (hot spot area), and the fourth level is the mirror area (clarification area).

[0038] In this step, setting electric heating systems of different powers means setting them according to the daily melting amount of the melting furnace by determining the total amount of electric melting energy, determining the electrode partitioning layout plan, determining the electrode material, calculating the resistance between electrodes, calculating the secondary side voltage, and calculating the current and current density, specifically including:

[0039] S110: Set the daily melting capacity of float glass melting furnace: ≥500t / d;

[0040] S120: Divide the bar area, foam area, hot spot area and mirror area into eight units, including the bar area (unit 1), foam area (units 2 and 3), hot spot area (units 4 and 5) and mirror area (units 6, 7 and 8);

[0041] S130: inserting a bubbler system into the mirror area;

[0042] S140: electrodes are arranged at the bottom of the melting furnace pool, wherein the electrode system is not provided in the 6th unit position area, and the number of electrodes arranged is shown in Table 1.

[0043] In this step, the formula for calculating the resistance between electrodes is:

[0044] Among them, R is the resistance value between electrodes, U is the voltage, I is the current, w is the angular frequency, c is the system capacitance, and L is the system inductance.

[0045] In this step, the whole kiln is equipped with 7 sets of electric heating systems in 4 zones. Each of the first 5 units is equipped with a group of 15 electrodes, and each of the last two units is equipped with 9 electrodes. Different numbers of zirconium oxide molybdenum electrodes can be used according to different melting furnace designs. The distance between each 2 electrodes is the same, forming an equilateral triangle power supply method. A voltage of 360 volts is applied, and the installed power is according to Table 1.

[0046] S200: The rod area, foam area, hot spot area and mirror area are heated by electric energy, and mineral fuel is added to the above areas at the same time, and the above area pools are heated by the mineral fuel auxiliary electric heating system.

[0047] In this step, the proportion of hydrogen fuel in the mineral fuel is not less than 40%, and the glass solution in each zone pool is heated by arranging a bottom-firing spray gun, and the glass solution is heated by a horizontal flame in the hot spot area and the mirror area.

[0048] The preferred method is to use electric heating in the rod area to save energy and materials, because the glass liquid temperature in the lower part of the molten pool is lower and the glass liquid resistance is higher, and there is float glass raw material waiting to be melted in the upper part of the molten pool. This area is only equipped with electric heating, and no hydrogen fuel heating is arranged.

[0049] Furthermore, spray gun units are arranged on the breast walls on the left and right sides of the melting furnace in each zone, and the spray gun nozzles of each nozzle unit are arranged symmetrically or crosswise with the same number on the left and right sides.

[0050] Furthermore, in the first-level bar area (pre-melting area), no hydrogen spray gun is set, in the second-level foam area (raw material melting area), two units of hydrogen spray guns are set, in the third-level hot spot area (hot spot area), two units of hydrogen spray guns are set, and in the fourth-level mirror area (clarification area), three units of hydrogen spray guns are set. The corresponding number and energy of hydrogen spray guns per unit in each area are shown in Table 1.

[0051] S300: adjusting the proportion of electric energy heating to 60% of the total heating energy, wherein the heating electric energy of the rod area and the foam area is adjusted to more than 40% of the total heating electric energy.

[0052] In this step, the ratio of electric energy to mineral fuel energy in the glass liquid is not less than 60:40, and a combined melting process of electric melting assisted by hydrogen energy and horizontal flame combustion energy is adopted.

[0053] Electricity accounts for 60% or more, and the preferred ratio is 60:40. The melting furnace is a unit-type all-hydrogen and all-oxygen float glass melting furnace, without a regenerator, and the hydrogen spray guns are arranged in opposite or cross-combustion.

[0054] Table 1: Number of electrodes, nozzles and spray guns in each zone

[0055]

[0056] In Table 1, the design energy consumption refers to the energy consumption index specified in the national and industry standards that the designed melting furnace should not exceed when melting each kilogram of glass liquid; the hydrogen-electricity ratio refers to the ratio of hydrogen energy and electric energy to the design energy when the melting furnace uses hydrogen energy and electric energy to melt glass raw materials. For example, the hydrogen-electricity ratio is 4:6, which means that hydrogen accounts for 40% of the total energy and electric energy accounts for 60% of the total energy.

[0057] S400: A neck gate with an automatically adjustable opening is set to separate the melting zone and the cooling zone, reduce the interference of the melting zone on the cooling zone, and optimize the melting process.

[0058] In this step, the electric melting furnace neck is provided with a water-cooled neck gate which automatically controls the opening and the depth of immersion in the glass liquid surface. The gate serves to separate the atmosphere of the melting part from the atmosphere of the cooling part, thereby optimizing the working environment for clarifying the glass liquid.

[0059] Furthermore, the clamping neck gate is made of high-temperature alloy GH2747 and sprayed with 20% yttria-stabilized zirconia, and is cooled by deionized water circulation, and can automatically adjust the clamping neck opening and the depth of immersion in the glass liquid.

[0060] Furthermore, the neck gate plate can also be made of refractory materials.

[0061] Furthermore, the neck gate plate can be composed of one or more pieces.

[0062] The clamping gate properly separates the melting section and the cooling section, reduces the influence of the melting section temperature, kiln pressure, atmosphere, etc. on the cooling section, and can effectively solve the problem of microbubbles in full hydrogen and full oxygen combustion melting.

[0063] Furthermore, when the glass liquid flows through the bottleneck, it is subjected to a certain stirring effect due to the change in the liquid flow cross section, thereby improving the uniformity of the composition, temperature, density and viscosity of the glass liquid.

[0064] Furthermore, the depth of the gate plate inserted into the glass liquid surface and the opening of the neck gate plate are reasonably controlled according to the process conditions. The quality of the glass liquid is optimized according to the cooling and cooling requirements of the glass liquid, the reflux requirements of the cooling part of the glass liquid, and the requirements of intercepting floating objects on the surface of the glass liquid.

[0065] Furthermore, before normal production, the regulating gate should be in an open state.

[0066] Furthermore, the gate position of the clamping neck is automatically controlled by a computer according to specific process requirements;

[0067] A vertical agitator or a horizontal agitator is arranged at the neck behind the neck gate;

[0068] The furnace arch, breast wall and bottom are equipped with a digital temperature control system, a digital kiln pressure control system, and an industrial television system for vertical detection of working conditions.

[0069] In addition, the melting furnace is equipped with auxiliary systems such as circulating cooling water system, power supply and distribution and electrical automatic control system, cooling air system, electric heating system, hydrogen and oxygen supply and distribution system, etc.

[0070] Furthermore, the above-mentioned systems use a computer system to digitally control melting parameters such as the temperature of various parts of the melting furnace, the pressure inside the furnace, the melting heating electric power, the combustion gas flow rate, and the glass liquid level.

[0071] Please refer to Figure 3 , Figure 4 The present invention also provides an electric melting sub-fire full hydrogen and full oxygen float glass melting furnace, which is used to implement the method described in the above embodiment, and the float glass melting furnace comprises:

[0072] A glass melting pool 1, wherein the glass melting pool 1 is used to melt minerals and is divided into a rod area, a foam area, a hot spot area and a mirror area according to the glass melting form. The sixth unit in the front area of ​​the mirror area is provided with a bubbler system 2;

[0073] Electrodes 3, which are arranged at the bottom of the glass melting pool 1, and which are combined into different heating systems for heating the minerals in the glass melting pool 1;

[0074] A breast wall 4, the breast wall is used to set a spray gun, and the spray gun is used to spray hydrogen fuel;

[0075] The neck 5 is arranged at the discharge port of the glass melting pool 1 , and an adjusting gate 51 is arranged inside the neck.

[0076] Furthermore, a furnace arch 14 is provided on the glass melting pool 1, and the glass melting pool 1 includes a furnace bottom 11 and a pool wall 12. Flues 13 are provided on both sides of the glass melting pool 1.

[0077] Furthermore, in order to enable the float glass melting furnace to implement the method of the above embodiment, the daily melting capacity of the float glass melting furnace is set at a minimum of 500 t / d.

[0078] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for melting electric sub-fire full hydrogen and full oxygen float glass, characterized in that: The steps include: The glass melting pool is divided into a rod area, a foam area, a hot spot area and a mirror area according to the form of the glass liquid during melting. The heating system is set at the bottom of the rod area, foam area, hot spot area and mirror area by determining the total amount of electric melting bottom plug-in energy, determining the electrode partitioning arrangement plan, determining the electrode material, calculating the resistance between electrodes, calculating the secondary side voltage, and calculating the current and current density. The bubbler system is inserted into the mirror area; the rod area, foam area, hot spot area and mirror area are divided into eight units, and a bottom-fired heating spray gun system is arranged on the breast wall, wherein the hydrogen energy consumption in the hot spot area and the mirror area accounts for more than 35% of the total energy consumption, and the calculation formula for the resistance between electrodes is: Among them, R is the resistance value between electrodes, U is the voltage, I is the current, w is the angular frequency, c is the system capacitance, and L is the system inductance; The rod area, foam area, hot spot area and mirror area are heated by electric energy, and mineral fuel is added to the above areas at the same time, and the above areas are heated by the mineral fuel auxiliary electric heating system, the proportion of hydrogen fuel in the mineral fuel is less than or equal to 40%, and the glass solution in each area is heated by setting a bottom-fired gas spray gun, and the surface of the glass solution is heated by a horizontal flame in the hot spot area and the mirror area; The proportion of electric energy heating is adjusted to more than 60% of the total heating energy, wherein the heating electric energy of the rod material area and the foam area is adjusted to more than 40% of the total heating electric energy; A neck gate with an automatically adjustable opening is set to separate the melting zone and the cooling zone, reduce the interference of the melting zone on the cooling zone, and optimize the melting process.

2. The method for melting electric sub-fire full hydrogen and full oxygen float glass according to claim 1, characterized in that: The energy ratio of electric energy to mineral fuel in the glass melt in the glass melting pool is not less than 60:

40.

3. The method for melting electric sub-fire full hydrogen and full oxygen float glass according to claim 2, characterized in that: The daily melting capacity of the glass melting pool is ≥500t / d.

Images