A waste heat power generation system and control method for a glass production line

Abstract

This invention relates to the field of waste heat utilization technology, and discloses a waste heat power generation system and control method for a glass production line. The waste heat power generation system includes a waste heat boiler, a power generation system, a water circulation system, a flue gas treatment system, an exhaust system, and an annealing waste heat utilization system. The flue gas outlet of the high-temperature flue gas zone and the flue gas inlet of the low-temperature flue gas zone are connected via the flue gas treatment system. The annealing waste heat utilization system includes a slow cooling zone waste heat utilization structure. The flue gas outlet of the high-temperature flue gas zone is connected to the slow cooling zone waste heat utilization structure, which is also connected to the flue gas inlet of the high-temperature flue gas zone and the flue gas treatment system. This fully utilizes the waste heat within the slow cooling zone waste heat utilization structure. Compared to the traditional method of introducing cold air into the annealing zone for waste heat utilization, this effectively improves the quality of waste heat and reduces the energy consumption of the slow cooling annealing zone.

Description

Technical Field

[0001] This invention relates to the field of waste heat utilization technology, specifically to a waste heat power generation system and control method for a glass production line. Background Technology

[0002] The glass industry consumes a large amount of energy. Currently, the average energy consumption of float glass is 6500kJ / kg to 7500kJ / kg of molten glass, of which more than 30% of the heat energy is discharged as waste gas. The utilization of waste heat from glass kilns is relatively mature and can be fully utilized. The temperature of this waste gas is generally 400-500℃. After passing through the high-temperature section in the waste heat boiler, the temperature drops to about 300℃, becoming low-quality waste heat. The steam generated subsequently has a low temperature and low utilization rate. Currently, there are no good methods for utilizing low-quality waste heat. Furthermore, the current method for utilizing waste heat from glass annealing furnaces is relatively simple, generally using this waste heat to heat the boiler water circulation, which has a low utilization rate. In response to the above problems, this application is proposed. Summary of the Invention

[0003] The purpose of this invention is to provide a waste heat power generation system and control method for glass production lines, which combines the waste heat from the glass annealing stage to improve the waste heat capacity of high-quality flue gas and ensure the efficiency of waste heat recovery and utilization.

[0004] The present invention is achieved through the following technical solution.

[0005] This invention discloses a waste heat power generation system for a glass production line, comprising a waste heat boiler, a power generation system, a water circulation system, a flue gas treatment system, an exhaust system, and an annealing waste heat utilization system. The waste heat boiler includes a high-temperature flue gas zone and a low-temperature flue gas zone. The high-temperature flue gas zone is connected to the flue gas discharge end of the glass kiln. The flue gas outlet of the high-temperature flue gas zone and the flue gas inlet of the low-temperature flue gas zone are connected through the flue gas treatment system. The annealing waste heat utilization system includes a slow cooling zone waste heat utilization structure. The flue gas outlet of the high-temperature flue gas zone is connected to the slow cooling zone waste heat utilization structure. The slow cooling zone waste heat utilization structure is connected to the flue gas inlet of the high-temperature flue gas zone and the flue gas treatment system. The waste heat boiler is connected to the exhaust system and the power generation system. The water circulation system is connected to the waste heat boiler and the power generation system.

[0006] Furthermore, the water circulation system includes a water supply preheating device, a condensing device, and a deoxygenation device. The condensing device is connected in sequence to the deoxygenation device and the water supply preheating device. The condensing device is connected to the power generation system. The water supply preheating device is connected to the waste heat boiler. The deoxygenation device is connected to the water makeup system.

[0007] Furthermore, the exhaust system includes a chimney, the flue gas outlet of the low-temperature flue gas zone of the waste heat boiler is connected to the water supply preheating device, and the water supply preheating device is connected to the exhaust system.

[0008] Furthermore, the exhaust system also includes a desulfurization treatment device.

[0009] Furthermore, the annealing waste heat utilization system also includes a rapid cooling zone waste heat utilization structure, which is connected to the water supply preheating device.

[0010] Furthermore, the flue gas treatment system includes a dust removal device and a denitrification device.

[0011] Furthermore, the waste heat utilization structure in the slow cooling zone is connected to an auxiliary interface, which is connected to other waste heat power generation systems in the glass production line.

[0012] Furthermore, the waste heat utilization structure in the rapid cooling zone includes a medium supply end, which is capable of supplying gas or water to the waste heat utilization structure in the rapid cooling zone, and the waste heat utilization structure in the rapid cooling zone is connected to the deaerator.

[0013] A control method for a waste heat power generation system in a glass production line, based on the aforementioned waste heat power generation system, includes the following steps:

[0014] High-temperature flue gas from the glass furnace enters the high-temperature flue gas zone of the waste heat boiler, and after heat exchange, it is discharged as medium-temperature flue gas.

[0015] A portion of the medium-temperature flue gas enters the waste heat utilization structure of the slow cooling zone to cool the annealing slow cooling zone, becoming medium-high temperature flue gas; the other portion of the medium-temperature flue gas enters the flue gas treatment system.

[0016] After the temperature rises, part of the medium- and high-temperature flue gas mixes with the medium- and high-temperature flue gas in the glass kiln and enters the high-temperature flue gas zone of the waste heat boiler, while the other part enters the flue gas treatment system.

[0017] After being treated by the flue gas treatment system, the medium-temperature flue gas enters the low-temperature flue gas zone and is then discharged through the exhaust system.

[0018] The waste heat boiler generates steam which enters the power generation system to generate electricity. The steam is then circulated back to the waste heat boiler through a water circulation system.

[0019] Furthermore, when the temperature of the high-temperature flue gas in the glass kiln of other glass production line waste heat power generation systems exceeds the set value, a portion of the medium-high temperature flue gas that has risen in temperature enters other glass production line waste heat power generation systems and mixes with the high-temperature flue gas from the glass kiln.

[0020] The beneficial effects of this invention are:

[0021] By cooling and circulating the medium-temperature flue gas in the annealing zone to raise its temperature, and then mixing it to a certain extent with the high-temperature flue gas according to the temperature ratio, the amount of high-quality waste heat entering the high-temperature flue gas zone is effectively increased, thereby achieving higher waste heat utilization efficiency. At the same time, the waste heat within the waste heat utilization structure of the slow cooling zone is fully utilized. Compared with the traditional method of introducing cold air into the annealing zone for waste heat utilization, this method effectively improves the quality of waste heat and reduces the energy consumption of the slow cooling annealing zone, achieving a double benefit. In addition, this method does not introduce new gas, which can reduce the load on the subsequent flue gas treatment system. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] Figure 1 This is a schematic diagram of a waste heat power generation system for a glass production line in Example 1;

[0025] Figure 2 This is a schematic diagram of a waste heat power generation system for a glass production line in Example 2. Detailed Implementation

[0026] The following is combined with Figure 1-2 The present invention will be described in detail below.

[0027] Example 1:

[0028] The present invention provides a waste heat power generation system for a glass production line, such as... Figure 1 The system includes a waste heat boiler 1, a power generation system 4, a water circulation system, a flue gas treatment system, an exhaust system, and an annealing waste heat utilization system. The waste heat boiler 1 includes a high-temperature flue gas zone 10 and a low-temperature flue gas zone 11, which can be separated by baffles or other structures. The inlet of the high-temperature flue gas zone 10 is connected to the flue gas outlet of the glass furnace 20. The flue gas outlet of the high-temperature flue gas zone 10 and the flue gas inlet of the low-temperature flue gas zone 11 are connected through the flue gas treatment system. Specifically, the flue gas treatment system includes a high-temperature electrostatic precipitator 91 and a denitrification reactor 92. The flue gas outlet of the high-temperature flue gas zone 10 is connected to the high-temperature electrostatic precipitator 91, the high-temperature electrostatic precipitator 91 is connected to the denitrification reactor 92, and the denitrification reactor 92 is connected to the inlet of the low-temperature flue gas zone 11.

[0029] The glass annealing furnace 21 is divided into three sections according to the glass annealing process: heating and holding section, slow zone stage and rapid cooling section.

[0030] The task of the heating and holding stage is to heat the glass products fed into the annealing furnace 21 to the annealing temperature. The heating rate should ensure that the temporary stress generated during the heating process does not exceed the ultimate strength of the glass itself to prevent the products from cracking. If the temperature of the products entering the annealing furnace is higher than the annealing temperature (this often happens when using high-speed forming machines), heating is not necessary; instead, they need to be cooled to the annealing temperature as quickly as possible and held at that temperature to ensure uniform temperature throughout the product and eliminate inherent internal stresses in the glass. During this stage, the annealing temperature and holding time must be determined. The annealing temperature can be calculated based on the chemical composition of the glass to determine the maximum annealing temperature. In production, a annealing temperature 20–30°C lower than the maximum annealing temperature is commonly used as the annealing holding temperature. Once the annealing temperature is determined, the holding time can be calculated based on the maximum allowable stress value of the glass products.

[0031] During the slow cooling stage, after the original stress in the glass is eliminated, new stress will be generated during the cooling process due to the high temperature. The magnitude of the new stress is controlled by the cooling rate. The slower the cooling rate, the smaller the newly generated permanent stress. Therefore, slow cooling must be carried out after heat preservation. The magnitude of the slow cooling rate depends on the allowable permanent stress value of the glass product; the larger the allowable value, the faster the cooling rate can be.

[0032] During the rapid cooling stage, when the glass cools below the strain point temperature, the temperature difference will only generate temporary stress. At this point, the glass can be cooled as quickly as possible, up to the kiln exit temperature, while ensuring that the glass product does not crack due to temporary stress.

[0033] The annealing waste heat utilization system includes a slow cooling zone waste heat utilization structure 212 and a fast cooling zone waste heat utilization structure 211, which are respectively set in the slow zone stage and the fast cooling zone section. The waste heat utilization structure includes a fan, a heat exchanger, etc. The flue gas outlet of the high-temperature flue gas zone 10 is connected to the slow cooling zone waste heat utilization structure 212. The slow cooling zone waste heat utilization structure 212 is connected to the flue gas inlet of the high-temperature flue gas zone 10 and the flue gas treatment system. The waste heat boiler 1 is connected to the exhaust system and the power generation system 4. The water circulation system is connected to the waste heat boiler 1 and the power generation system 4.

[0034] The water circulation system includes a water supply preheating device 54, a condensing device 43, and a deoxygenation device 53. The condensing device 43 is connected in sequence to the deoxygenation device 53 and the water supply preheating device 54. The condensing device 43 is connected to the power generation system 4. The water supply preheating device 54 is connected to the waste heat boiler 1. The deoxygenation device 53 is connected to the water makeup system 52.

[0035] The exhaust system includes a desulfurization treatment device 8 and a chimney 6. The flue gas outlet of the low-temperature flue gas zone 11 of the waste heat boiler 1 is connected to the water supply preheating device 54, which is connected to the exhaust system.

[0036] Preferably, the waste heat utilization structure 211 in the rapid cooling zone is connected to the water supply preheating device 54.

[0037] The waste heat power generation system of the glass production line also includes a temperature detection system. The temperature detection system is used to detect the exhaust temperature of the glass kiln and the exhaust temperature of the waste heat utilization structure 212 in the slow cooling zone. The exhaust from the waste heat utilization structure 212 in the slow cooling zone enters the flue gas inlet and flue gas treatment system of the high temperature flue gas zone 10 in proportion.

[0038] Workflow: High-temperature flue gas (400-500℃) from the glass kiln enters the high-temperature flue gas zone 10 of the waste heat boiler 1. After heat exchange, it is discharged as medium-temperature flue gas (around 300℃). Based on the temperature at the slow cooling stage, the proportion of medium-temperature flue gas entering the waste heat utilization structure 212 and the flue gas treatment system in the slow cooling zone is controlled. The higher the temperature at the slow cooling stage is compared to the medium-temperature flue gas (around 300℃), the greater the proportion of medium-temperature flue gas entering the waste heat utilization structure 212 in the slow cooling zone. Another part of the medium-temperature flue gas enters the flue gas treatment system, and after dust removal and denitrification, it enters the low-temperature flue gas zone 11. The lower the temperature at the slow cooling stage is compared to the temperature of the medium-temperature flue gas, the smaller the proportion of medium-temperature flue gas entering the waste heat utilization structure 212 in the slow cooling zone. After passing through the waste heat utilization structure 212 in the slow cooling zone, all the discharged gas enters the low-temperature flue gas zone 11.

[0039] The steam generated after heat exchange in the waste heat boiler 1 enters the steam turbine 41 in the power generation system 4, which drives the generator 42 to generate electricity. After power generation, the steam enters the condensing device 43, passes through the condenser and cooling tower, and then enters the deaerator 53 under the action of the water pump 51. After deaeration, it enters the water supply preheating device 54. The water supply preheating device 54 is connected to the waste heat boiler 1 to form a water circulation loop.

[0040] After passing through the low-temperature flue gas zone 11 and the economizer, the flue gas enters the chimney 6 and is discharged under the action of the fan through the desulfurization treatment device 8. Optionally, the flue gas enters the chimney 6 and is discharged after passing through the desulfurization treatment device 8 and the water supply preheating device 54.

[0041] The medium-temperature flue gas entering the waste heat utilization structure 212 in the slow cooling zone is heated by the waste heat from glass annealing, which achieves the effect of slow cooling annealing of glass while improving the quality of waste heat, thus turning the medium-temperature flue gas into medium-high temperature flue gas.

[0042] In the design of waste heat power generation systems for glass kilns, there is always an optimal operating temperature. The temperature of the glass melting furnace flue gas is affected by multiple factors, and the flue gas flow rate and temperature will change at each production stage and at different production cycles. When the temperature of the glass melting furnace flue gas is higher than the optimal operating temperature, the valve opening is controlled according to the pre-set temperature ratio, so that the medium and high temperature flue gas enters the high temperature flue gas of the glass melting furnace in proportion for mixing, and enters the high temperature flue gas zone 10 at the optimal operating temperature, increasing the amount of high-quality waste heat flue gas. The remaining medium and high temperature flue gas enters the flue gas treatment system, and after dust removal and denitrification, it enters the low temperature flue gas zone 11.

[0043] The above method effectively increases the amount of high-quality waste heat entering the high-temperature flue gas zone 10, thereby achieving higher waste heat utilization efficiency. At the same time, it fully utilizes the waste heat within the waste heat utilization structure of the slow cooling zone. Compared with the traditional method of introducing cold air into the annealing zone for waste heat utilization, it effectively improves the quality of waste heat and reduces the energy consumption of the slow cooling annealing zone, achieving a double benefit. In addition, this method does not introduce new gas, which can reduce the load on the subsequent flue gas treatment system.

[0044] In the waste heat utilization structure 211 of the rapid cooling zone, cold air is blown in by a fan to rapidly cool the glass. Then, the gas with waste heat enters the water preheating device 54 to heat the water before being discharged through the chimney 6.

[0045] When the water volume in the water circulation system 52 (generally a water supply pipeline) is lower than the predetermined value, the water replenishment system 52 replenishes the water volume. The water enters the water circulation system through the deaeration device 53.

[0046] Example 2: Based on Example 1, the waste heat utilization structure 212 in the slow cooling zone is connected to the auxiliary interface 7, which is connected to other waste heat power generation systems in the glass production line. For example... Figure 2 Since each waste heat utilization system operates under different conditions, the medium and high temperature flue gas in different systems can be shared and used through the auxiliary interface 7. For example, if the gas volume in the No. 1 waste heat utilization system is low and the temperature is high, the medium and high temperature flue gas from other systems can be used to supplement it.

[0047] Example 3: Based on Example 1 or 2, the waste heat utilization structure 211 of the rapid cooling zone includes a medium supply end 31, which can supply gas or water to the waste heat utilization structure 211 of the rapid cooling zone. The waste heat utilization structure 211 of the rapid cooling zone is connected to the deoxygenation device 53.

[0048] The waste heat utilization structure 211 in the rapid cooling zone includes a water pump and a fan. When water needs to be added in the water circulation, the medium supply end 31 supplies water to the waste heat utilization structure 211 in the rapid cooling zone, and the water is used directly to cool the annealing rapid cooling section. The heated water enters the deoxygenation device 53 and then enters the water circulation.

[0049] The waste heat utilization structure 211 in the rapid cooling zone can be set in two sets, one of which is gas-cooled and the other is water-cooled.

[0050] Alternatively, only one set of waste heat utilization structure 211 for the rapid cooling zone can be set up, in which the heat exchange pipe is for both water and air. When the set amount of water is insufficient in the water circulation, water is introduced into the pipe.

[0051] This eliminates one heat exchange step and improves the efficiency of waste heat utilization.

[0052] A control method for a waste heat power generation system in a glass production line, based on the waste heat power generation system in Embodiment 1 or 2 above, includes the following steps:

[0053] High-temperature flue gas from the glass kiln enters the high-temperature flue gas zone 10 of the waste heat boiler 1, and after heat exchange, it is discharged as medium-temperature flue gas.

[0054] A portion of the medium-temperature flue gas enters the waste heat utilization structure 212 in the slow cooling zone to cool the annealing slow cooling zone, becoming medium-high temperature flue gas; the other portion of the medium-temperature flue gas enters the flue gas treatment system.

[0055] After the temperature rises, part of the medium- and high-temperature flue gas mixes with the medium- and high-temperature flue gas in the glass kiln and enters the high-temperature flue gas zone 10 of the waste heat boiler 1, while the other part enters the flue gas treatment system.

[0056] After being treated by the flue gas treatment system, the medium-temperature flue gas enters the low-temperature flue gas zone 11 and is then discharged through the exhaust system.

[0057] The waste heat boiler 1 generates steam which enters the power generation system 4 to generate electricity. Then the steam is circulated back to the waste heat boiler 1 through the water circulation system.

[0058] Optionally, when the temperature of the high-temperature flue gas in the glass kiln of other glass production line waste heat power generation systems exceeds the set value, a portion of the medium-high temperature flue gas that has increased in temperature enters other glass production line waste heat power generation systems and mixes with the high-temperature flue gas from the glass kiln.

[0059] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand and implement the present invention. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A glass line waste heat power generation system, characterized by: The system includes a waste heat boiler (1), a power generation system (4), a water circulation system, a flue gas treatment system, an exhaust system, and an annealing waste heat utilization system. The waste heat boiler (1) includes a high-temperature flue gas zone (10) and a low-temperature flue gas zone (11). The high-temperature flue gas zone (10) is connected to the flue gas discharge end of the glass melting furnace. The flue gas outlet of the high-temperature flue gas zone (10) and the flue gas inlet of the low-temperature flue gas zone (11) are connected through the flue gas treatment system. The annealing waste heat utilization system includes a slow cooling zone waste heat utilization structure (212). The flue gas outlet of the high-temperature flue gas zone (10) is connected to the slow cooling zone waste heat utilization structure (212). The slow cooling zone waste heat utilization structure (212) is connected to the flue gas inlet of the high-temperature flue gas zone (10) and the flue gas treatment system. The waste heat boiler (1) is connected to the exhaust system and the power generation system (4). The water circulation system is connected to the waste heat boiler (1) and the power generation system (4). High-temperature flue gas from the glass melting furnace enters the high-temperature flue gas zone (10) of the waste heat boiler (1), and after heat exchange, it is discharged as medium-temperature flue gas. A portion of the medium-temperature flue gas enters the waste heat utilization structure (212) in the slow cooling zone to cool the annealing slow cooling zone and becomes medium-high temperature flue gas; another portion of the medium-temperature flue gas enters the flue gas treatment system. Based on the temperature at the slow cooling stage, the proportion of medium-temperature flue gas entering the waste heat utilization structure (212) of the slow cooling zone and the flue gas treatment system is controlled. The higher the temperature at the slow cooling stage is compared to the temperature of the medium-temperature flue gas, the greater the proportion of medium-temperature flue gas entering the waste heat utilization structure (212) of the slow cooling zone. Another part of the medium-temperature flue gas enters the flue gas treatment system. When the temperature at the slow cooling stage is lower than the temperature of the medium-temperature flue gas, the smaller the proportion of medium-temperature flue gas entering the waste heat utilization structure (212) of the slow cooling zone, and all the exhaust gas after passing through the waste heat utilization structure (212) of the slow cooling zone enters the low-temperature flue gas zone (11). After the temperature rises, part of the medium- and high-temperature flue gas mixes with the medium- and high-temperature flue gas in the glass melting furnace and enters the high-temperature flue gas zone (10) of the waste heat boiler (1), while the other part enters the flue gas treatment system. After being treated by the flue gas treatment system, the medium-temperature flue gas enters the low-temperature flue gas zone (11) and is then discharged, and then discharged through the exhaust system; When the temperature of the flue gas in the glass melting furnace is higher than the optimal operating temperature, the valve opening is controlled according to the pre-set temperature ratio, so that the medium and high temperature flue gas enters the high temperature flue gas in the glass melting furnace in proportion for mixing, and enters the high temperature flue gas zone (10) at the optimal operating temperature.

2. The waste heat power generation system for a glass production line according to claim 1, characterized in that: The water circulation system includes a water supply preheating device (54), a condensing device (43), and a deoxygenation device (53). The condensing device (43) is connected in sequence to the deoxygenation device (53) and the water supply preheating device (54). The condensing device (43) is connected to the power generation system (4). The water supply preheating device (54) is connected to the waste heat boiler (1). The deoxygenation device (53) is connected to the water replenishment system (52).

3. The waste heat power generation system for a glass production line according to claim 2, characterized in that: The exhaust system includes a chimney (6), and the flue gas outlet of the low-temperature flue gas zone (11) of the waste heat boiler (1) is connected to the water supply preheating device (54), which is connected to the exhaust system.

4. The waste heat power generation system for a glass production line according to claim 3, characterized in that: The exhaust system also includes a desulfurization treatment device (8).

5. A waste heat power generation system for a glass production line according to claim 2, 3, or 4, characterized in that: The annealing waste heat utilization system also includes a rapid cooling zone waste heat utilization structure (211), which is connected to the water supply preheating device (54).

6. A waste heat power generation system for a glass production line according to claim 5, characterized in that: The flue gas treatment system includes a dust removal device and a denitrification device.

7. A waste heat power generation system for a glass production line according to claim 6, characterized in that: The waste heat utilization structure (212) in the slow cooling zone is connected to the auxiliary interface (7), which is connected to other waste heat power generation systems in the glass production line.

8. A waste heat power generation system for a glass production line according to claim 6, characterized in that: The waste heat utilization structure (211) of the rapid cooling zone includes a medium supply end (31), which can supply gas or water to the waste heat utilization structure (211) of the rapid cooling zone, and the waste heat utilization structure (211) of the rapid cooling zone is connected to the deoxygenation device (53).

9. A control method for a waste heat power generation system in a glass production line, based on the waste heat power generation system in a glass production line according to any one of claims 1-8, characterized in that: Includes the following steps: High-temperature flue gas from the glass melting furnace enters the high-temperature flue gas zone (10) of the waste heat boiler (1), and after heat exchange, it is discharged as medium-temperature flue gas. A portion of the medium-temperature flue gas enters the waste heat utilization structure (212) in the slow cooling zone to cool the annealing slow cooling zone and becomes medium-high temperature flue gas; another portion of the medium-temperature flue gas enters the flue gas treatment system. After the temperature rises, part of the medium- and high-temperature flue gas mixes with the medium- and high-temperature flue gas in the glass melting furnace and enters the high-temperature flue gas zone (10) of the waste heat boiler (1), while the other part enters the flue gas treatment system. After being treated by the flue gas treatment system, the medium-temperature flue gas enters the low-temperature flue gas zone (11) and is then discharged, and then discharged through the exhaust system; The waste heat boiler (1) generates steam which enters the power generation system (4) to generate electricity. Then the steam is circulated back to the waste heat boiler (1) through the water circulation system.

10. A control method for a waste heat power generation system in a glass production line according to claim 9, characterized in that: When the temperature of the high-temperature flue gas in the glass melting furnace of other glass production line waste heat power generation systems exceeds the set value, part of the medium-high temperature flue gas that has risen in temperature enters other glass production line waste heat power generation systems and mixes with the warm flue gas from the glass melting furnace.

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