High-temperature flue gas waste heat utilization system and method of glass kiln

Abstract

The invention provides a high-temperature flue gas waste heat utilization system and method for a glass kiln, and the system comprises a heat exchanger, and an air inlet of the heat exchanger is used for obtaining high-temperature flue gas discharged by the glass kiln; the gas inlet pipe is used for inputting first mixed gas; a heat exchange pipe is arranged in the heat exchanger; an air inlet of the heat exchange pipe communicates with the air inlet pipe; the fuel channel is communicated with the air outlet of the heat exchange tube and the glass kiln; and the first mixed gas exchanges heat with the high-temperature flue gas entering the heat exchanger and is heated to form second mixed gas, and the second mixed gas enters the glass kiln through the fuel channel to be combusted. A phase change process is reduced, the operation is simple, the fuel with a higher combustion heat value is generated, more heat is released in the glass kiln, and the energy-saving effect is remarkable.

Description

Technical Field

[0001] The present invention relates to the technical field of glass kilns and energy recovery, and in particular to a system and method for utilizing waste heat from high-temperature flue gas of a glass kiln. Background Art

[0002] Since the Industrial Revolution, with the rapid increase in the consumption of fossil fuels, the amount of greenhouse gases such as CO2 emitted into the atmosphere by humans has increased year by year, greatly threatening and destroying the greenhouse gas balance system in the atmosphere, increasing the risk of extreme climate disasters, and seriously threatening the human living environment. With the advancement of science and technology and the enhancement of human environmental awareness, how to reduce CO2 emissions has become a special concern of countries around the world. Developing a low-carbon economy to achieve energy conservation and emission reduction has become an important way to cope with global warming and the deteriorating environment.

[0003] While supporting the rapid development of the national economy, the glass industry consumes a lot of energy during the production process. Its energy consumption mainly consists of electricity consumed by the operation of production equipment and fuel consumed by melting glass liquid. Fuel consumption accounts for more than 80% of energy costs, and part of the heat released by the fuel is discharged into the atmosphere with the flue gas of the glass kiln. The kiln flue gas not only takes away a lot of waste heat, but also emits harmful gases such as CO2, NOx and SO2. In order to solve the problems of high energy consumption and serious pollution in the glass industry, people have carried out a lot of research work, developed a series of energy-saving and emission reduction technologies and achieved certain results. Among them, full oxygen combustion has been widely promoted and applied in the production line of ultra-white rolled glass.

[0004] U.S. Patent No. 6,113,874 discloses a thermochemical heat recovery method that can be used for a furnace using a regenerator, wherein a combustion product stream formed in the furnace passes through a first regenerator to heat the first regenerator and cool the combustion product, and then a portion of the cooled combustion product is combined with a fuel to form a mixture, which passes through a second heated regenerator, wherein the mixture undergoes an endothermic reaction to form a synthesis gas, which is then introduced into the furnace and burned. The efficiency of thermochemical waste heat recovery depends largely on the methane conversion rate in the reforming reaction, because it indicates how much of the heat in the flue gas can be converted into chemical energy of new synthetic fuel, and the methane conversion rate depends on the temperature that the fuel and flue gas can reach in the heat storage chamber.

[0005] The currently disclosed thermochemical regenerator technology adopts the phase-changing process of the traditional air kiln regenerator. There is a gas purge process during the phase-changing process, which causes short-term energy fluctuations in the glass kiln, and the operation is relatively complicated. Summary of the invention

[0006] Based on the above content, the present invention provides a system and method for utilizing waste heat from high-temperature flue gas in a glass kiln, aiming to solve the technical problems in the prior art of low efficiency and complex operation of waste heat utilization using a heat storage chamber.

[0007] A high-temperature flue gas waste heat utilization system for a glass furnace, characterized by comprising:

[0008] Heat exchanger, the air inlet of the heat exchanger is used to obtain the high-temperature flue gas discharged from the glass furnace;

[0009] An air intake pipe, used for inputting a first mixed gas;

[0010] The heat exchanger has a heat exchange tube inside, and the air inlet of the heat exchange tube is connected to the air inlet pipe;

[0011] A fuel channel, connecting the gas outlet of the heat exchange tube and the glass furnace;

[0012] The first mixed gas exchanges heat with the high-temperature flue gas entering the heat exchanger and is heated to form a second mixed gas. The second mixed gas enters the glass kiln through the fuel channel for combustion.

[0013] Furthermore, the heat exchanger includes a shell, a heat exchange cavity is formed inside the shell, a heat exchange tube is arranged in the heat exchange cavity, and the high-temperature flue gas exchanges heat with the first mixed gas in the heat exchange cavity and the heat exchange tube.

[0014] Furthermore, the smoke outlet channel of the glass furnace is connected to the heat flow air inlet of the heat exchange chamber of the heat exchanger.

[0015] Furthermore, the heat flow outlet of the heat exchange chamber of the heat exchanger is connected to the medium and low temperature waste heat utilization device through the smoke exhaust channel;

[0016] The high-temperature flue gas is discharged into the medium- and low-temperature waste heat utilization device through the smoke exhaust channel after heat exchange with the first mixed gas in the heat exchange tube.

[0017] Further, the air inlet pipe connects the heat exchange pipe and a gas mixing device;

[0018] The gas mixing device mixes the externally input natural gas and reformed gas to form a first mixed gas, which is then input into the heat exchange tube.

[0019] Furthermore, the natural gas is methane, and the reformed gas is water vapor, or carbon dioxide gas, or a mixed gas of water vapor and carbon dioxide gas.

[0020] Furthermore, the heat flow air inlet of the heat exchange chamber of the heat exchanger is located at the top end of the first side of the shell, and the heat flow air outlet of the heat exchange chamber is located at the bottom end of the second side of the shell;

[0021] The first side and the second side of the housing are opposite to each other.

[0022] Further, the air inlet of the heat exchange tube is located at the top end of the second side of the shell of the heat exchanger, and the air outlet of the heat exchange tube is located at the bottom end of the first side of the shell;

[0023] The first side and the second side of the housing are opposite to each other.

[0024] A method for utilizing waste heat from high-temperature flue gas of a glass furnace, using the aforementioned system for utilizing waste heat from high-temperature flue gas of a glass furnace, comprising:

[0025] Step A1, introducing high-temperature flue gas discharged from the glass furnace into a heat exchanger, and passing the first mixed gas into a heat exchange tube of the heat exchanger;

[0026] Step A2, the high-temperature flue gas and the first mixed gas are heat exchanged in a heat exchanger, and the first mixed gas is heated to form a second mixed gas;

[0027] Step A3: the second mixed gas enters the glass furnace through the fuel channel for combustion.

[0028] Furthermore, in step A3, the high-temperature flue gas and the first mixed gas in the heat exchange tube are subjected to heat exchange and then discharged into the medium- and low-temperature waste heat utilization device.

[0029] The beneficial technical effect of the present invention is that by transferring the heat of the smoke outlet channel of the glass kiln to the first mixed gas, the first mixed gas is heated to a certain temperature, an endothermic reaction occurs, and the thermal energy is converted into chemical energy to generate a second mixed gas with a higher combustion calorific value as fuel, which is burned in the glass kiln. On the one hand, the phase change process is reduced and the operation is simple; on the other hand, a fuel with a higher combustion calorific value is generated, which releases more heat in the glass kiln, resulting in a significant energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a high-temperature flue gas waste heat utilization system of a glass furnace according to the present invention;

[0031] Figure 2 This is a flow chart of the steps of a method for utilizing waste heat from high-temperature flue gas of a glass furnace according to the present invention;

[0032] in,

[0033] 1-Glass kiln;

[0034] 2-Heat exchanger;

[0035] 3- Smoke outlet channel;

[0036] 4-Fuel channel;

[0037] 5-heat exchange tube;

[0038] 6- Gas mixing device;

[0039] 7- Smoke exhaust channel;

[0040] 8- Natural gas;

[0041] 9-Reforming gas;

[0042] 10-intake pipe;

[0043] 11-oxidizing agent;

[0044] 12-Medium and low temperature waste heat utilization device. DETAILED DESCRIPTION

[0045] 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.

[0046] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0047] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0048] See also Figure 1 The present invention provides a high-temperature flue gas waste heat utilization system for a glass furnace, comprising:

[0049] A heat exchanger (2), wherein an air inlet of the heat exchanger (2) is used to obtain high-temperature flue gas discharged from the glass furnace (1);

[0050] An air intake pipe (10) for inputting a first mixed gas;

[0051] The heat exchanger (2) has a heat exchange tube (5) inside, and the air inlet of the heat exchange tube (5) is connected to the air inlet pipe (10);

[0052] A fuel channel (4) communicating with the gas outlet of the heat exchange tube (5) and the glass furnace (1);

[0053] The first mixed gas exchanges heat with the high-temperature flue gas entering the heat exchanger (2) and is heated to form a second mixed gas. The second mixed gas enters the glass furnace (1) through the fuel channel (4) and is burned.

[0054] Specifically, in the glass furnace (1), the second mixed gas is burned in the glass furnace (1) with the aid of the oxidant (11).

[0055] Specifically, the oxidant (11) is oxygen or air.

[0056] By transferring the heat of the smoke outlet channel of the glass kiln to the first mixed gas, the first mixed gas is heated to a certain temperature, an endothermic reaction occurs, and the thermal energy is converted into chemical energy to generate a second mixed gas with a higher combustion calorific value as fuel, which is burned in the glass kiln. On the one hand, the phase change process is reduced and the operation is simple; on the other hand, a fuel with a higher combustion calorific value is generated, which releases more heat in the glass kiln and has a significant energy-saving effect.

[0057] Furthermore, the heat exchanger (2) comprises a shell, a heat exchange chamber is formed inside the shell, a heat exchange tube (5) is arranged in the heat exchange chamber, and the high-temperature flue gas in the heat exchange chamber exchanges heat with the first mixed gas in the heat exchange tube (5).

[0058] Specifically, the heat exchange tube (5) is in a curved shape, and the heat exchange tube (5) is bent as much as possible in the heat exchange chamber of the heat exchanger (2), so that the high-temperature flue gas and the natural gas / reforming gas can fully complete the heat exchange.

[0059] Furthermore, the smoke outlet channel (3) of the glass furnace (1) is connected to the heat flow air inlet of the heat exchange chamber of the heat exchanger (2).

[0060] Specifically, a smoke outlet channel is provided on the top of the glass furnace (1), and the smoke outlet channel is connected to the heat flow air inlet of the heat exchange chamber.

[0061] Furthermore, the heat flow outlet of the heat exchange chamber of the heat exchanger (2) is connected to the medium and low temperature waste heat utilization device (12) through the smoke exhaust channel (7);

[0062] After heat exchange between the high-temperature flue gas and the first mixed gas in the heat exchange tube (5), the flue gas is discharged into the medium- and low-temperature waste heat utilization device (12) through the flue gas exhaust channel (7).

[0063] Specifically, the smoke outlet channel (3) is connected to the top end of the first side of the shell of the heat exchanger (2) and is in communication with the heat exchange chamber. The bottom of the second side of the shell of the heat exchanger (2) is provided with a smoke outlet channel (7) in communication with the heat exchange chamber. The heat exchange tube (5) is distributed in a serpentine shape, and the two ends of the heat exchange tube (5) are respectively located on both sides of the shell of the heat exchanger.

[0064] After the high-temperature flue gas is heat exchanged, its temperature is reduced and it enters the medium- and low-temperature waste heat utilization device (12). The medium- and low-temperature waste heat utilization device (12) can be, for example, one or more waste heat utilization devices used for heating natural gas / reforming gas mixed gas, preheating raw materials, preheating oxidants, preheating boilers, preheating power generation, etc.

[0065] The glass furnace may be, for example, an oxy-fuel furnace.

[0066] Furthermore, the air inlet pipe (10) connects the heat exchange pipe (5) and a gas mixing device (6);

[0067] The gas mixing device (6) mixes the externally input natural gas (8) and the reformed gas (9) to form a first mixed gas, which is then input into the heat exchange tube (5).

[0068] The natural gas (8) and the reformed gas (9) are mixed evenly in the mixing device 6 to form a first mixed gas. After heat exchange, a fuel with a higher combustion calorific value is generated. The second mixed gas can release more heat when burned in the glass kiln, thereby reducing energy consumption.

[0069] Furthermore, the natural gas (8) is methane, and the reformed gas (9) is water vapor, or carbon dioxide gas, or a mixed gas of water vapor and carbon dioxide gas.

[0070] A heat exchanger (2) is arranged on the smoke outlet channel (3) of the glass kiln furnace (1), and a first mixed gas of natural gas / reformed gas introduced from an air inlet pipe (10) is introduced into the heat exchanger (2). The first mixed gas exchanges heat with the high-temperature smoke in the smoke outlet channel (3), and the heat in the smoke outlet channel of the glass kiln is transferred to the mixed gas of natural gas / reformed gas. The mixed gas is heated to a certain temperature, an endothermic reaction occurs, and the heat energy is converted into chemical energy. The fuel generated by the same volume of natural gas has a higher combustion calorific value, and enters the glass kiln (1) through the fuel channel (4) to burn with the oxidant (11), thereby realizing the utilization of high-temperature waste heat.

[0071] The endothermic reaction formula is as follows:

[0072] Formula 1:

[0073] Formula 2:

[0074] Methane and water vapor absorb heat and generate carbon monoxide gas and hydrogen with higher calorific value of combustion.

[0075] Methane and carbon dioxide gases absorb heat and generate carbon monoxide gas and hydrogen with higher combustion calorific value.

[0076] Specifically, the volume ratio of natural gas to reformed gas is not higher than 1:4.

[0077] Furthermore, the heat flow air inlet of the heat exchange chamber of the heat exchanger (2) is located at the top end of the first side of the shell, and the heat flow air outlet of the heat exchange chamber is located at the bottom end of the second side of the shell;

[0078] The first side and the second side of the housing are opposite to each other.

[0079] Furthermore, the air inlet of the heat exchange tube (5) is located at the top end of the second side of the shell of the heat exchanger (2), and the air outlet of the heat exchange tube (5) is located at the bottom end of the first side of the shell;

[0080] The first side and the second side of the housing are opposite to each other.

[0081] See also Figure 2 The present invention also provides a method for utilizing waste heat from high-temperature flue gas of a glass furnace, using the above-mentioned system for utilizing waste heat from high-temperature flue gas of a glass furnace, comprising:

[0082] Step A1, introducing high-temperature flue gas discharged from the glass furnace (1) into the heat exchanger (2), and passing the first mixed gas into the heat exchange tube of the heat exchanger (2);

[0083] Step A2, the high-temperature flue gas and the first mixed gas are heat exchanged in the heat exchanger (2), and the first mixed gas is heated to form a second mixed gas;

[0084] Step A3: the second mixed gas enters the glass furnace through the fuel channel for combustion.

[0085] Furthermore, in step A3, the high-temperature flue gas and the first mixed gas in the heat exchange tube (5) are subjected to heat exchange and then discharged into the medium- and low-temperature waste heat utilization device (12).

[0086] The high-temperature flue gas in the glass furnace (1) enters the heat exchange chamber of the heat exchanger (2) from the smoke outlet channel (3), transfers heat to the fluid in the heat exchange tube (5), and then the temperature is reduced. The flue gas is discharged from the smoke outlet channel (7) and enters the medium- and low-temperature waste heat utilization device (12) for waste heat recovery and utilization.

[0087] At the same time, the natural gas (8) and the reformed gas (9) are evenly mixed in the gas mixing device (6) and then enter the heat exchange tube (5) through the air inlet pipe (10). The first mixed gas absorbs heat from the high-temperature flue gas in the heat exchange tube (5). When the first mixed gas reaches a certain temperature, the mixed gas undergoes an endothermic reforming reaction to generate a reformed fuel with a higher calorific value, i.e., the second mixed gas.

[0088] The reformed fuel is discharged from the gas outlet of the heat exchange tube (5) and enters the glass furnace (1) through the fuel channel (4), where it burns with the gaseous oxidant (11) to generate high-temperature flue gas.

[0089] The inventor proposed to use a heat exchanger instead of a heat storage chamber to transfer the waste heat of high-temperature flue gas to the fuel and perform an endothermic reaction, thereby realizing the utilization of high-temperature waste heat and reducing the phase change process. On the one hand, the temperature of the reforming reaction can be maintained in a relatively high and stable range. After the reforming reaction of natural gas, fuel with a higher calorific value of combustion is generated, which enters the glass kiln through the outlet pipe of the heat exchange tube to react with the oxidizing gas to release more heat, which can further reduce energy consumption. The conversion rate of methane is improved, and on the other hand, the cumbersome process is reduced, and the energy-saving effect is more obvious.

[0090] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-temperature flue gas waste heat utilization system for a glass furnace, characterized in that: include: A heat exchanger (2), wherein the air inlet of the heat exchanger (2) is used to obtain high-temperature flue gas discharged from the glass furnace (1); An air intake pipe (10) for inputting a first mixed gas; The heat exchanger (2) has a heat exchange tube (5) inside, and the air inlet of the heat exchange tube (5) is connected to the air inlet pipe (10); A fuel channel (4) communicating with the gas outlet of the heat exchange tube (5) and the glass furnace (1); The first mixed gas exchanges heat with the high-temperature flue gas entering the heat exchanger (2) and is heated to form a second mixed gas. The second mixed gas enters the glass furnace (1) through the fuel channel (4) and is burned.

2. A high-temperature flue gas waste heat utilization system for a glass furnace as claimed in claim 1, characterized in that: The heat exchanger (2) comprises a shell, a heat exchange cavity is formed inside the shell, the heat exchange tube (5) is arranged in the heat exchange cavity, and the high-temperature flue gas in the heat exchange cavity and the first mixed gas in the heat exchange tube (5) perform heat exchange.

3. A high-temperature flue gas waste heat utilization system for a glass furnace as claimed in claim 2, characterized in that: The smoke outlet channel (3) of the glass furnace (1) is connected to the heat flow air inlet of the heat exchange chamber of the heat exchanger (2).

4. A high-temperature flue gas waste heat utilization system for a glass furnace as claimed in claim 2, characterized in that: The heat flow outlet of the heat exchange cavity of the heat exchanger (2) is connected to the medium and low temperature waste heat utilization device (12) through the smoke exhaust channel (7); After heat exchange between the high-temperature flue gas and the first mixed gas in the heat exchange tube (5), the high-temperature flue gas is discharged into the medium- and low-temperature waste heat utilization device (12) through the flue gas exhaust passage (7).

5. A high-temperature flue gas waste heat utilization system for a glass furnace as claimed in claim 2, characterized in that: The air inlet pipe (10) connects the heat exchange pipe (5) and a gas mixing device (6); The gas mixing device (6) mixes the externally input natural gas (8) and the reformed gas (9) to form the first mixed gas, which is then input into the heat exchange tube (5).

6. A high-temperature flue gas waste heat utilization system for a glass furnace as claimed in claim 5, characterized in that: The natural gas (8) is methane, and the reformed gas (9) is water vapor, or carbon dioxide gas, or a mixed gas of water vapor and carbon dioxide gas.

7. A high-temperature flue gas waste heat utilization system for a glass furnace as claimed in claim 2, characterized in that: The heat flow air inlet of the heat exchange cavity of the heat exchanger (2) is located at the top end of the first side of the shell, and the heat flow air outlet of the heat exchange cavity is located at the bottom end of the second side of the shell; The first side and the second side of the housing are opposite to each other.

8. A high-temperature flue gas waste heat utilization system for a glass furnace as claimed in claim 2, characterized in that: The air inlet of the heat exchange tube (5) is located at the top end of the second side of the shell of the heat exchanger (2), and the air outlet of the heat exchange tube (5) is located at the bottom end of the first side of the shell; The first side and the second side of the housing are opposite to each other.

9. A method for utilizing waste heat from high-temperature flue gas of a glass furnace, characterized in that: A high-temperature flue gas waste heat utilization system for a glass furnace according to any one of claims 1 to 8, comprising: Step A1, introducing high-temperature flue gas discharged from the glass furnace (1) into the heat exchanger (2), and passing the first mixed gas into the heat exchange tube of the heat exchanger (2); Step A2, the high-temperature flue gas and the first mixed gas are heat exchanged in the heat exchanger (2), and the first mixed gas is heated to form a second mixed gas; Step A3: the second mixed gas enters the glass furnace through the fuel channel for combustion.

10. A method for utilizing waste heat from high-temperature flue gas of a glass furnace as claimed in claim 9, characterized in that: In step A3, the high-temperature flue gas and the first mixed gas in the heat exchange tube (5) are subjected to heat exchange and then discharged into the medium- and low-temperature waste heat utilization device (12).

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