Vehicle bottom type roasting furnace energy saving system and method

Abstract

The invention discloses a vehicle bottom type roasting furnace energy saving system and method. The system comprises a plurality of vehicle bottom furnaces, a communicating flue unit, an oxygen supplementing unit and an oxygen content monitoring control unit. The communicating flue unit is used for conveying high-concentration volatile flue gas generated by one source car bottom furnace in a low-temperature roasting stage into a hearth of the other target car bottom furnace in a high-temperature roasting stage through an auxiliary smoke exhaust flue, a communicating flue and a volatile supplement flue. The oxygen content monitoring control unit monitors the oxygen content of a target hearth in real time, and instructs the oxygen supplementing unit to accurately supplement oxygen through the controller, so that the oxygen content is maintained within the range of 0.5%-1.0%, and stable and sufficient combustion of volatile components is ensured. According to the system, cascade and cross-furnace utilization of volatile chemical latent heat is achieved, external fuel consumption of the high-temperature furnace is remarkably reduced, the purposes of energy conservation, consumption reduction and emission reduction are achieved, and the system is high in integration degree, safe, controllable and particularly suitable for carbon enterprises with multiple car bottom furnaces connected in parallel for production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of car bottom roasting furnace, in particular to a car bottom roasting furnace energy-saving system and method. BACKGROUND

[0002] The car bottom roasting furnace (car bottom furnace) is a key equipment for producing high-end carbon products (such as graphite electrodes, special graphite, etc.), which is widely used due to its precise furnace temperature control, good product quality, and strong production flexibility. However, its biggest disadvantage is that the energy consumption is extremely high, which can be more than twice that of the traditional ring roasting furnace, which seriously restricts its popularization and application.

[0003] The main reason for high energy consumption is the process characteristics: a large amount of high-calorific-value combustible volatile (mainly bitumen smoke) is precipitated during the low-temperature heating stage of 300 to 500℃ of carbon products, but due to the protective atmosphere of oxygen isolation in the furnace, the volatile cannot be burned. The traditional method is usually to directly discharge the combustible volatile and send it to a dedicated incinerator for treatment, which not only wastes the chemical energy contained therein, but also requires additional energy consumption for incineration disposal. During the high-temperature heating stage above 700℃, the product itself has little volatile analysis, and a large amount of external fuel needs to be burned to maintain rapid heating, and the energy consumption is concentrated.

[0004] In the prior art, although attempts have been made to utilize the volatile inside a single furnace, due to the different requirements for atmosphere and temperature in different roasting stages, it is difficult to achieve efficient, stable and full combustion of the volatile inside a single furnace. For example, during the low-temperature stage when a large amount of volatile is produced, the temperature inside the furnace is relatively low, lacking a high-temperature environment and sufficient oxygen to ignite and continuously burn the volatile. If a large amount of air is forcibly supplemented to assist combustion, the furnace may be excessively cooled, which may damage the roasting process curve. Therefore, there is an urgent need for a system and method that can utilize energy across furnace chambers and stages to solve the above problems. SUMMARY

[0005] The present application aims to solve the problem of high energy consumption of existing car bottom roasting furnaces, in particular, how to safely and efficiently utilize the high-concentration volatile precipitated by the product itself as fuel inside the furnace to replace part of the external energy consumption, while ensuring product quality and production safety.

[0006] To achieve the above technical purpose, the following technical solutions are adopted: On the one hand, the present application provides a car bottom roasting furnace energy-saving system, comprising a plurality of car bottom furnaces, a connecting flue unit, an oxygen supplementing unit, and an oxygen content monitoring and control unit. The communicating flue unit comprises a flue gas discharging auxiliary flue arranged on each trolley hearth, a communicating flue connecting different trolley hearths, and a volatile component supplementing flue arranged on each trolley hearth; the inlet of the flue gas discharging auxiliary flue is communicated with the hearth of the trolley hearth, and the outlet thereof is connected with the inlet of the communicating flue through a flue gas discharging auxiliary valve; the inlet of the volatile component supplementing flue is connected with the outlet of the communicating flue, and the outlet thereof is communicated with the hearth of the trolley hearth, and the volatile component supplementing flue is provided with a volatile component supplementing valve; The oxygen supplementing unit comprises an oxygen supplementing fan, an oxygen supplementing collecting pipeline connecting different trolley hearths, and an oxygen supplementing pipeline arranged on each trolley hearth; the outlet of the oxygen supplementing fan is connected with the inlet of the oxygen supplementing collecting pipeline, the inlet of the oxygen supplementing pipeline is connected with the outlet of the oxygen supplementing collecting pipeline, and the outlet thereof is communicated with the hearth of the trolley hearth, and the oxygen supplementing pipeline is provided with an oxygen supplementing valve; The oxygen content monitoring and controlling unit is arranged on each trolley hearth and comprises an oxygen content detecting instrument, a sampling fan, and a controller; the inlet of the sampling fan is communicated with the hearth of the trolley hearth through a sampling pipeline, the sampling pipeline is provided with a sampling switch valve, and the outlet of the sampling fan is connected with the oxygen content detecting instrument; the signal input end of the controller is electrically connected with the oxygen content detecting instrument, and the control output end thereof is electrically connected with the oxygen supplementing valve on the trolley hearth.

[0007] Further, the flue gas discharging auxiliary flue is arranged in parallel with the original flue gas discharging main flue on the trolley hearth, and the flue gas discharging main flue is provided with a main flue gas discharging valve; the outlet of the flue gas discharging main flue is connected with a flue gas collecting pipeline, and the flue gas collecting pipeline is sequentially communicated with a flue gas incineration device, a flue gas discharging fan, and a chimney.

[0008] Further, a plurality of volatile component supplementing flues are arranged on each trolley hearth, the inlets of the volatile component supplementing flues are connected with the outlet of the communicating flue, and the outlets thereof are respectively communicated with different positions of the hearth of the trolley hearth.

[0009] Further, a plurality of oxygen supplementing pipelines are arranged on each trolley hearth, the inlets of the oxygen supplementing pipelines are connected with the outlet of the oxygen supplementing collecting pipeline, and the outlets thereof are respectively communicated with different positions of the hearth of the trolley hearth.

[0010] Further, the inlet of the oxygen supplementing fan is connected with a cold air pipeline and a hot air pipeline in parallel, the cold air pipeline is provided with a cold air switch valve, and the hot air pipeline is provided with a hot air switch valve.

[0011] On the other hand, the present application provides a trolley hearth type roasting furnace energy saving method using the above system, which comprises the following steps: S1. From the plurality of trolley hearths, a trolley hearth generating high concentration volatile components in a low temperature roasting stage is selected as a source trolley hearth, and a trolley hearth in a high temperature roasting stage is selected as a target trolley hearth. S2. opening the auxiliary flue gas discharge regulating valve on the auxiliary flue of the source car bottom furnace and opening the volatile supplement regulating valve on one or more volatile supplement flues of the target car bottom furnace, so that the volatile flue gas generated by the source car bottom furnace is introduced into the hearth of the target car bottom furnace through the communication flue; S3. opening the sampling switch valve of the target car bottom furnace, starting the sampling fan and the oxygen content detector, and monitoring the real-time oxygen content data in the hearth of the target car bottom furnace; S4. starting the oxygen supplement fan, and adjusting the opening degree of the oxygen supplement regulating valve on one or more oxygen supplement pipelines according to the real-time oxygen content data, so as to supplement oxygen into the hearth of the target car bottom furnace for combustion of the volatile flue gas; Preferably, in step S1, the source car bottom furnace is a furnace chamber in a low-temperature baking stage of 300-500°C, and the target car bottom furnace is a furnace chamber in a high-temperature baking stage of above 700°C.

[0012] Preferably, in step S4, the oxygen content in the hearth of the target car bottom furnace is maintained within the range of 0.5%-1.0%.

[0013] Preferably, in step S4, the hot air recovered through waste heat recovery is preferentially introduced as the oxygen supplement source.

[0014] Preferably, when the source car bottom furnace ends the low-temperature baking stage, the corresponding auxiliary flue gas discharge regulating valve, the corresponding volatile supplement regulating valve of the target car bottom furnace, and the sampling switch valve are closed, and a new source furnace and target furnace combination can be selected from multiple car bottom furnaces, and steps S1-S4 are repeated.

[0015] Compared with the prior art, the present application provides an energy-saving system and method for a car bottom type baking furnace, which has the following remarkable beneficial effects: 1. Significant energy saving and consumption reduction: By directly introducing the volatile generated by the low-temperature furnace chamber into the high-temperature furnace chamber for combustion, the chemical energy of the volatile is efficiently recovered and utilized, and the external fuel consumption in the high-temperature stage is greatly reduced.

[0016] 2. High system integration and convenient modification: The system can be constructed in combination with the existing car bottom furnace, and can be realized by adding a communication flue, an oxygen supplement and a monitoring system, and the investment is relatively low.

[0017] 3. Safety and controllability: Through oxygen content monitoring and feedback control, precise dynamic adjustment of the oxygen supplement amount is realized, the stable and sufficient combustion of the volatile in the furnace is ensured, and at the same time, the oxygen concentration in the furnace is strictly controlled within a safe range, thereby completely avoiding the risk of product oxidation, temperature loss of control or deflagration.

[0018] 4. Easy maintenance: The oxygen content monitoring system is external and equipped with a valve to control the sampling timing, which effectively avoids the contamination and damage of precision instruments by tar generated at low temperatures, and improves the long-term reliability of the system. Attached Figure Description

[0019] The present invention will now be described with reference to the accompanying drawings.

[0020] Figure 1 This is a process flow diagram of the system of the present invention.

[0021] In the diagram: 1-Main flue exhaust regulating valve; 2-Auxiliary flue exhaust; 3-Auxiliary flue exhaust regulating valve; 4-Connecting flue; 5-Volatile matter replenishment flue; 6-Volatile matter replenishment regulating valve; 7-Sampling switch valve; 8-Oxygen content detection instrument; 9-Sampling fan; 10-Oxygen replenishment regulating valve; 11-Oxygen replenishment pipeline; 12-Oxygen replenishment collection pipeline; 13-Oxygen replenishment fan; 14-Cold air switch valve; 15-Hot air switch valve. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, the energy-saving system of the car-bottom type roasting furnace of the present invention mainly consists of multiple car-bottom furnaces (numbered 1#, 2#, 3#, ...#), a connecting flue unit, an oxygen supplementation unit, and an oxygen content monitoring and control unit; The original flue gas system is retained, including: each car bottom furnace is equipped with its own main flue gas duct, on which a main flue gas exhaust regulating valve 1 is installed. The main flue gas ducts of all car bottom furnaces eventually converge into a flue gas collection pipe. This flue gas collection pipe connects in sequence to the flue gas combustion equipment, the exhaust fan, and the chimney, forming a standard flue gas treatment and emission path.

[0024] The connecting flue unit consists of: each car bottom furnace has a secondary flue 2 connected to its furnace chamber, with a secondary flue flue regulating valve 3 installed at its outlet. All secondary flues 2 are connected to a common connecting flue 4. Additionally, each car bottom furnace has two volatile matter supplementary flues 5, with their inlets connected to the connecting flue 4 and their outlets leading to different locations within the furnace chamber. Each volatile matter supplementary flue 5 is equipped with a volatile matter supplementary regulating valve 6. The original main flue and secondary flues 2 are connected in parallel.

[0025] The oxygen supplement unit is an oxygen supplement fan 13 outlet connected to an oxygen supplement collecting pipeline 12. Each car bottom furnace is connected to the oxygen supplement collecting pipeline 12 through two oxygen supplement pipelines 11, and the oxygen supplement pipeline 11 outlet is connected to the furnace, and an oxygen supplement regulating valve 10 is arranged on the furnace. Before the inlet of the oxygen supplement fan 13, a cold air pipeline and a hot air pipeline are connected in parallel, which are controlled by a cold air switch valve 14 and a hot air switch valve 15 respectively, and the design aims to save fuel to the maximum extent. The hot air comes from the waste heat recovery system of the flue gas incineration equipment or the recovered waste heat of other process sections. By opening the hot air switch valve 15 and closing the cold air switch valve 14, high-temperature hot air can be sent into the furnace as combustion-supporting air, further reducing the consumption of external fuel required to maintain the furnace temperature. When the waste heat system is not available or is in a maintenance state, the cold air mode can be switched, that is, the hot air switch valve 15 is closed and the cold air switch valve 14 is opened, which ensures the reliability and flexibility of the system under different working conditions.

[0026] The oxygen content monitoring control unit is independently provided with a set of oxygen content monitoring control unit for each car bottom furnace. It includes an oxygen content detector 8, a sampling fan 9, a sampling switch valve 7 and a controller (not shown in the figure). The oxygen content detector 8 and the sampling fan 9 adopt an external design and are connected to the furnace through a flue gas sampling pipeline; the sampling fan 9 draws the furnace gas and sends it to the oxygen content detector 8 for analysis. The controller receives the oxygen content signal and outputs a control instruction to the oxygen supplement regulating valve 10 of the car bottom furnace to form a closed-loop control.

[0027] The energy-saving method using the system is as follows: Suppose that the current car bottom furnace 1# is in a low-temperature roasting stage of 400℃ and is generating a large amount of volatile matter, which is determined as a source car bottom furnace. The car bottom furnace 3# is in a high-temperature roasting stage of 800℃ and needs to consume a large amount of fuel, which is determined as a target car bottom furnace.

[0028] 1. Establish a volatile matter conveying path: open the auxiliary flue gas discharge regulating valve 3 of the source car bottom furnace, and appropriately close the main flue gas discharge regulating valve 1 thereof. At the same time, open the two volatile matter supplement regulating valves 6 of the target car bottom furnace. At this time, the volatile matter flue gas generated by the source car bottom furnace enters the communication flue 4 through the auxiliary flue gas discharge 2 under the action of the negative pressure of the furnace itself, and is conveyed to the furnace of the target car bottom furnace through the two volatile matter supplement flues 5 of the target car bottom furnace.

[0029] 2. Monitoring and control: open the sampling switch valve 7 of the target car bottom furnace, start the sampling fan 9 and the oxygen content detector 8, and monitor the oxygen content in the furnace in real time.

[0030] 3. Oxygen-enriched combustion: start the oxygen-enriching blower 13, preferentially introduce the heat air recovered by the waste heat recovery as the oxygen source, and open the heat air switch valve 15. The controller compares the real-time oxygen content data with the target oxygen content value set by the user. If the oxygen content is too high, reduce the opening of the oxygen-enriching regulating valve 10; if the oxygen content is too low, increase the opening. Through this dynamic adjustment, the oxygen content of the target hearth is accurately stabilized in the range of 0.5%-1.0%, which can ensure that the volatile matter is ignited and continuously burned to release heat, and can also avoid excessive combustion to cause local temperature to be too high or consume too much oxygen to affect the product process.

[0031] 4. Switching and recycling: after several hours, the source hearth 1# ends the low-temperature stage, and the volatile matter yield decreases, so the auxiliary flue exhaust regulating valve 3 is closed, and the main flue exhaust is restored. At the same time, the volatile matter supplement regulating valve 6 and the sampling switch valve 7 of the target hearth 3# are closed. At this time, another hearth in the low-temperature stage can be selected as the new source hearth, and another high-temperature hearth can be selected as the new target hearth, and the above process can be repeated to realize continuous energy recycling of the entire hearth group.

[0032] Other details of the present application that are not fully described are well known to those skilled in the art.

[0033] It should be noted that the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusions, so that processes, methods, articles, or equipment containing a series of elements not only include those elements, but also include other elements not explicitly listed, or inherent to such processes, methods, articles, or equipment.

[0034] The protection scope of the present application is not limited to the technical solutions disclosed in the specific embodiments, and any modification, equivalent replacement, improvement, etc. made according to the technical essence of the present application to the above embodiments falls within the protection scope of the present application.

Claims

1. An energy-saving system for a car-bottom type roasting furnace, comprising multiple car-bottom furnaces; characterized in that: It also includes a flue gas connection unit, an oxygen supply unit, and an oxygen content monitoring and control unit; The connecting flue unit includes a secondary flue (2) installed on each car bottom furnace, a connecting flue (4) connecting different car bottom furnaces, and a volatile matter supplement flue (5) installed on each car bottom furnace; the inlet of the secondary flue (2) is connected to the furnace chamber of the car bottom furnace, and its outlet is connected to the inlet of the connecting flue (4) through a secondary flue flue exhaust regulating valve (3); the inlet of the volatile matter supplement flue (5) is connected to the outlet of the connecting flue (4), and its outlet is connected to the furnace chamber of the car bottom furnace; a volatile matter supplement regulating valve (6) is installed on the volatile matter supplement flue (5). The oxygen replenishment unit includes an oxygen replenishment fan (13), an oxygen replenishment collection pipe (12) connecting different car bottom furnaces, and an oxygen replenishment pipe (11) installed on each car bottom furnace; the outlet of the oxygen replenishment fan (13) is connected to the inlet of the oxygen replenishment collection pipe (12), the inlet of the oxygen replenishment pipe (11) is connected to the outlet of the oxygen replenishment collection pipe (12), and its outlet is connected to the furnace of the car bottom furnace; an oxygen replenishment regulating valve (10) is installed on the oxygen replenishment pipe (11). The oxygen content monitoring and control unit is installed on each car bottom furnace, including an oxygen content detection instrument (8), a sampling fan (9) and a controller; the inlet of the sampling fan (9) is connected to the furnace chamber of the car bottom furnace through a sampling pipe, and a sampling switch valve (7) is installed on the sampling pipe; the outlet of the sampling fan (9) is connected to the oxygen content detection instrument (8); the signal input terminal of the controller is electrically connected to the oxygen content detection instrument (8), and its control output terminal is electrically connected to the oxygen supplementation regulating valve (10) on the car bottom furnace.

2. The energy-saving system for a car-bottom type roasting furnace according to claim 1, characterized in that: The auxiliary flue is connected in parallel with the original main flue on the car bottom furnace. The main flue is equipped with a main flue flue flue regulating valve (1). The outlet of the main flue is connected to a flue gas collection pipe, which is connected in sequence to the flue gas combustion equipment, the flue gas fan and the chimney.

3. The energy-saving system for a car-bottom type roasting furnace according to claim 1, characterized in that: Multiple volatile matter replenishment flues (5) are provided on each car bottom furnace. The inlet of each volatile matter replenishment flue (5) is connected to the outlet of the connecting flue (4), and the outlet is connected to different positions in the furnace chamber of the car bottom furnace.

4. The energy-saving system for a car-bottom type roasting furnace according to claim 1, characterized in that: Multiple oxygen supply pipes (11) are provided on each car bottom furnace. The inlet of each oxygen supply pipe (11) is connected to the outlet of the oxygen supply collection pipe (12), and the outlet is connected to different positions in the furnace chamber of the car bottom furnace.

5. The energy-saving system for a car-bottom type roasting furnace according to claim 1, characterized in that: The oxygen supplement fan (13) has a cold air pipe and a hot air pipe connected in parallel at the inlet front end. A cold air switch valve (14) is installed on the cold air pipe, and a hot air switch valve (15) is installed on the hot air pipe.

6. An energy-saving method for a car-bottom type roasting furnace using the system described in any one of claims 1-5, characterized in that: Includes the following steps: S1. From the multiple car bottom furnaces, select one car bottom furnace that is in the low-temperature roasting stage and produces high concentration of volatiles as the source car bottom furnace, and select one car bottom furnace that is in the high-temperature roasting stage as the target car bottom furnace. S2. Open the auxiliary flue flue gas regulating valve (3) on the auxiliary flue gas duct (2) of the source car bottom furnace, and open the volatile matter supplement regulating valve (6) on one or more volatile matter supplement flue gas ducts (5) of the target car bottom furnace, so that the volatile matter flue gas generated by the source car bottom furnace is led into the furnace of the target car bottom furnace through the connecting flue gas duct (4); S3. Open the sampling switch valve (7) of the target car bottom furnace, start the sampling fan (9) and oxygen content detection instrument (8) to monitor the real-time oxygen content data in the furnace of the target car bottom furnace; S4. Start the oxygen supply fan (13) and, based on the real-time oxygen content data, adjust the opening of the oxygen supply regulating valve (10) on one or more oxygen supply pipelines (11) through the controller to supply oxygen into the furnace of the target car bottom furnace, so that the volatile flue gas can be burned in it.

7. The energy-saving method for a car-bottom type roasting furnace according to claim 6, characterized in that: In step S1, the source car bottom furnace is a furnace chamber in the low-temperature roasting stage of 300 to 500°C, and the target car bottom furnace is a furnace chamber in the high-temperature roasting stage of 700°C or above.

8. The energy-saving method for a car-bottom type roasting furnace according to claim 6, characterized in that: In step S4, the oxygen content in the target car bottom furnace is controlled to be maintained within the range of 0.5% to 1.0%.

9. The energy-saving method for a car-bottom type roasting furnace according to claim 6, characterized in that: In step S4, hot air that has undergone waste heat recovery is preferentially introduced as a source of supplementary oxygen.

10. The energy-saving method for a car-bottom type roasting furnace according to claim 6, characterized in that: After the source car bottom furnace finishes the low-temperature roasting stage, the corresponding auxiliary flue gas exhaust regulating valve (3) and the target car bottom furnace corresponding volatile matter supplement regulating valve (6) and sampling switch valve (7) are closed. A new source furnace and target furnace combination can be selected from multiple car bottom furnaces, and steps S1 to S4 are repeated.

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