Ignition system for improving flame rigidity of RTO furnace

Abstract

The utility model discloses an ignition system for improving flame rigidity of an RTO furnace, which comprises the RTO furnace, a burner is arranged on the RTO furnace, a combustion fan is connected with the burner through a combustion pipeline, the burner is connected with a natural gas supply device through a natural gas main pipeline, and the burner is further connected with the natural gas main pipeline through a natural gas auxiliary pipeline. An ignition gas valve is arranged on the natural gas auxiliary pipeline, a main gas valve and a natural gas pressure transmitter are arranged on the natural gas main pipeline, emptying pipelines are connected to the natural gas auxiliary pipeline and the natural gas main pipeline, and emptying valves are arranged on the emptying pipelines; the RTO furnace is provided with an ignition transformer and two flame detectors, the main gas valve, the emptying valve, the ignition gas valve and the ignition transformer form an execution module, the two flame detectors and the natural gas pressure transmitter form a sensor module, and the execution module, the sensor module and the control module form an SIS ignition control system. The SIS ignition control system is adopted, the flame probe and the like are added, and the ignition success rate is increased.

Description

TECHNICAL FIELD

[0001] The utility model relates to RTO furnace ignition system and control technical field, concretely is a kind of ignition system of improving RTO furnace flame rigidity. BACKGROUND

[0002] High pressure polyethylene device RTO furnace unit is used to handle device bunker waste gas, belongs to environmental protection equipment, waste gas is oxidized at high temperature by ceramic heat storage material, so that VOC in waste gas is decomposed into carbon dioxide and water.RTO furnace since 2018, non-planned parking and production fluctuation occur several times, its main reason is ignition system, according to actual operation, in combination with in-depth analysis on site, present ignition control system has the following problems: first, current RTO furnace adopts Honeywell EC7810A controller for ignition control, the controller realizes its function by electronic circuit, its ignition control scheme is solidified, fault information is not clear, and the interaction signal with main control system PLC is less, and troubleshooting is difficult, and for on-site installation, controller cannot be cooled, and fault occurs frequently;Second, present ignition control scheme is unreasonable, and the reasonable optimization of ignition logic cannot be realized, so that ignition success rate is low;Third, key instrument equipment, natural gas and combustion air proportional regulating valve still adopt multi-link regulating butterfly valve, and there is large dead zone in connecting rod type structure valve, so as to cause poor instrument regulation accuracy.

[0003] In summary, RTO furnace is caused by the backwardness of on-site equipment and control component technology, and the control concept is relatively old, and it is seriously disconnected with modernization and intelligent industrial control, and many factors cause unstable operation of RTO furnace. INVENTION CONTENTS

[0004] (I) technical problem solved

[0005] In view of the deficiencies of prior art, the utility model provides an ignition system for improving the rigidity of RTO furnace flame to solve the problems that the present ignition control scheme is solidified, troubleshooting is difficult, the controller cannot be cooled, and at the same time, due to unreasonable ignition control scheme, the ignition success rate is low, and multi-link regulating butterfly valve is still used, there is large dead zone, so as to cause poor instrument regulation accuracy, and RTO furnace is caused to be unstable.

[0006] (II) technical scheme

[0007] To achieve the above object, the utility model provides the following technical scheme: a kind of ignition system for improving RTO furnace flame rigidity, including RTO furnace, combustion air fan, burner and natural gas supply equipment, the outer top of the RTO furnace is provided with the burner, the combustion air fan is connected with the upper end of the burner by combustion pipeline, the upper end of the burner is connected with the natural gas supply equipment by natural gas main pipeline;First natural gas pressure transmitter, two main gas valves, second natural gas pressure transmitter and natural gas regulating valve are sequentially arranged on the natural gas main pipeline;The natural gas regulating valve is connected with the combustion pipeline by pipeline, the distance between the natural gas regulating valve and the burner is 2m;

[0008] The upper end of the burner is also connected with one end of natural gas auxiliary pipeline, the other end of the natural gas auxiliary pipeline is connected with the natural gas main pipeline;The first natural gas pressure transmitter is arranged at the interface of the natural gas main pipeline and the natural gas auxiliary pipeline;One end of emptying pipeline one is connected on the natural gas main pipeline between two main gas valves, and a first emptying valve is arranged on the emptying pipeline one;Two ignition gas valves are arranged on the natural gas auxiliary pipeline, and the other end of emptying pipeline two is connected on the natural gas auxiliary pipeline between two ignition gas valves, and a second emptying valve is arranged on the emptying pipeline two;The other end of the emptying pipeline one is connected with the emptying pipeline two;

[0009] Two flame detectors are arranged on the inner top of the RTO furnace, and an ignition transformer is further arranged on the outer upper end of the RTO furnace;Two main gas valves, the first emptying valve, two ignition gas valves, the second emptying valve and the ignition transformer constitute an execution module, two flame detectors, the first natural gas pressure transmitter and the second natural gas pressure transmitter constitute a sensor module, and the execution module, the sensor module and the control module constitute an SIS ignition control system.

[0010] Preferably, the inner part of the RTO furnace is divided into A combustion chamber and B combustion chamber;A combustion air regulating valve is arranged on the combustion pipeline connected with the upper end of the burner, the combustion air regulating valve is an angular travel pneumatic control butterfly valve, and the natural gas regulating valve is a mechanical pressure regulating valve.

[0011] Preferably, an emptying valve is further arranged on the emptying pipeline two.

[0012] Preferably, a pressure reducing valve, a locking valve and a Y-type filter are sequentially arranged on the natural gas main pipeline between the natural gas supply equipment and the first natural gas pressure transmitter.

[0013] Preferably, the volume ratio of natural gas supplied by the natural gas supply equipment to air input by the combustion air fan is 10:1.

[0014] Preferably, the combustion air regulating valve, the two main gas valves, the two ignition gas valves, the first exhaust valve and the second exhaust valve are all powered by instrument air.

[0015] Preferably, a safety isolation barrier is provided between the control module and the execution module.

[0016] Advantages

[0017] Compared with the prior art, the utility model provides a kind of ignition system of improving RTO furnace flame rigidity, with following advantages:

[0018] 1, completely solve the ignition difficult and abnormal flameout problem of existing RTO furnace ignition system, after using the system of the utility model, RTO furnace is ignited successfully once each time.Reformation is completed until abnormal flameout does not occur for several months of time, and safe and stable running time is greatly improved compared with before reformation, which provides strong guarantee for long-period stable operation of environmental protection device;

[0019] 2, the system of the utility model can realize control logic visualization, under the condition that guaranteeing SIL safety level unchanged, using SIS ignition control system replaces existing ignition system local controller (Honeywell EC7810A), and safety isolation barrier is additionally provided, so that control scheme is transparent, configuration logic readability is strong, program logic optimization operability is strong;

[0020] 3, the distance of traditional natural gas regulating valve from burner is 8m, and because distance is relatively long, the time of natural gas to burner is relatively long, causing furnace temperature regulation lag;And existing RTO furnace utilizes furnace average temperature to control natural gas and combustion air regulating valve, uses two PID controllers to control independently, ignores the importance of air-fuel ratio, and then flame rigidity of combustion chamber is insufficient, and flame is light yellow, and internal pressure fluctuation of furnace is prone to cause flameout.The best distance of the system of the utility model between natural gas regulating valve and burner is 2m, the best air-gas ratio is determined as 10:1, flame detection probe is additionally provided, discharge arc time of spark plug is prolonged, ignition success rate is improved, and the stability of flame is enhanced, and ignition failure caused by rapid cooling can be avoided to a certain extent;The existing combustion air regulating valve with multi-link structure is reselected, and angular stroke pneumatic control butterfly valve with equal percentage flow characteristics is selected, to avoid a series of problems, such as large mechanical transmission error, low regulation accuracy and large dead zone, which seriously restrict the stability of ignition system.

[0021] 4, the system of the utility model perfects fault query function, and first alarm is given to important shutdown interlock, PLC instrument number trend in original ignition system is added to reformed historical trend server and SOE record, and when equipment is abnormal, fault reason can be accurately locked in first time. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is the flow schematic view of the RTO furnace ignition system of the utility model;

[0023] Figure 2 It is the whole module connection schematic view of the RTO furnace SIS ignition control system of the utility model;

[0024] Figure 3 It is the step sequence diagram of the prior RTO furnace ignition control system;

[0025] Figure 4 It is the step sequence diagram of the RTO furnace SIS ignition control system of the utility model.

[0026] In the drawing: 1, RTO furnace;2, combustion air fan;3, combustion air regulating valve;4, SIS ignition control system;5, second natural gas pressure transmitter;6, main gas valve;7, first natural gas pressure transmitter;8, Y type filter;9, pressure reducing valve;10, burner;11, natural gas supply equipment;12, natural gas main pipeline;13, natural gas auxiliary pipeline;14, emptying valve;15, natural gas regulating valve;16, ignition gas valve;17, emptying pipeline one;18, first emptying valve;19, emptying pipeline two;20, second emptying valve;21, flame detector;22, ignition transformer;23, locking valve. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the utility model will be described clearly and completely below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all the other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the utility model.

[0028] Please refer to Figure 1 , Figure 2 and Figure 4 for further detailed description of the utility model.

[0029] The utility model provides a kind of ignition system embodiment of improving RTO furnace flame rigidity, including RTO furnace 1, combustion fan 2, burner 10 and natural gas supply equipment 11, RTO furnace 1 is provided with burner 10 on outside, combustion fan 2 is connected with the upper end of burner 10 by combustion pipeline, and the upper end of burner 10 is connected with natural gas supply equipment 11 by natural gas main pipeline 12;Natural gas main pipeline 12 is sequentially provided with first natural gas pressure transmitter 7, two main gas valves 6, second natural gas pressure transmitter 5 and natural gas regulating valve 15;Natural gas regulating valve 15 is connected with combustion pipeline by pipeline, and the distance between natural gas regulating valve 15 and burner 10 is 2m, extend spark plug discharge arc time, start combustion fan 2 in advance when igniting, combustion air regulating valve 3 is opened to ignition position (25%), meet the control principle of " three simultaneously " of ignition, and one-time ignition success can be realized;

[0030] The upper end of burner 10 is also connected with one end of natural gas auxiliary pipeline 13, and the other end of natural gas auxiliary pipeline 13 is connected with natural gas main pipeline 12;First natural gas pressure transmitter 7 is arranged at the interface of natural gas main pipeline 12 and natural gas auxiliary pipeline 13;One end of emptying pipeline one 17 is connected on natural gas main pipeline 12 between two main gas valves 6, and first emptying valve 18 is arranged on emptying pipeline one 17;Two ignition gas valves 16 are arranged on natural gas auxiliary pipeline 13, emptying pipeline two 19 is connected on natural gas auxiliary pipeline 13 between two ignition gas valves 16, and second emptying valve 20 is arranged on emptying pipeline two 19;The other end of emptying pipeline one 17 is connected with emptying pipeline two 19;

[0031] Referring to Figure 1 And Figure 2 Two flame detectors 21 are arranged on the inner top of RTO furnace 1, and ignition transformer 22 is also arranged on the outer upper end of RTO furnace 1;Two main gas valves 6, first emptying valve 18, two ignition gas valves 16, second emptying valve 20 and ignition transformer 22 constitute execution module, two flame detectors 21, first natural gas pressure transmitter 7 and second natural gas pressure transmitter 5 constitute sensor module, execution module, sensor module and control module constitute SIS ignition control system 4, and control module is PLC or single-chip microcomputer;

[0032] The inner part of the RTO furnace 1 is A combustion chamber and B combustion chamber; the combustion air fan 2 is connected with the combustion air adjusting valve 3 on the upper end of the combustion tube of the burner 10, the combustion air adjusting valve 3 is an angular stroke pneumatic control butterfly valve, can have equal percentage flow characteristics, effectively avoids the production abnormality caused by insufficient control precision; the natural gas adjusting valve 15 is a mechanical pressure adjusting valve, and the distance from the burner 10 is 2 m; the volume ratio of the natural gas supplied by the natural gas supply equipment 11 and the air input by the combustion air fan 2 is 10:1, can effectively enhance the stability of the flame while accurately controlling the optimal air-gas ratio; the emptying pipeline two 19 is further provided with the emptying valve 14; the natural gas main pipeline 12 between the natural gas supply equipment 11 and the first natural gas pressure transmitter 7 is sequentially provided with the pressure reducing valve 9, the locking valve 23 and the Y-type filter 8, the Y-type filter 8 can filter the impurities in the natural gas; the combustion air adjusting valve 3, the two main gas valves 6, the two ignition gas valves 16, the first emptying valve 18 and the second emptying valve 20 are all powered by instrument air; the two flame detectors 21 are prevented from being damaged by furnace backfire by instrument air;

[0033] Please refer to Figure 4 The working process of the system is as follows: the pressure reducing valve 9 and the locking valve 23 are opened, the natural gas from the natural gas storage tank 11 passes through the Y-type filter 8, the first natural gas pressure transmitter 7 and the main gas valve 6 in sequence through the natural gas main pipeline 12, and is discharged to the safe area by the emptying valve 14 through the first emptying pipeline 17 and the first emptying valve 18; at the same time, the natural gas is input into the natural gas auxiliary pipeline 13 through the first natural gas pressure transmitter 7, and enters the emptying pipeline 19 through the ignition gas valve 16, and is discharged to the safe area by the emptying valve 14 through the second emptying valve 20; the pressure reducing valve 9, the locking valve 23, the first natural gas pressure transmitter 7, the two main gas valves 6, the first emptying valve 18, the two ignition gas valves 16 and the second emptying valve 20 are closed, the air is input into the RTO furnace 1 through the combustion air fan 2 and the combustion air adjusting valve 3 through the combustion pipeline, and the RTO furnace 1 is purged;

[0034] The combustion air fan 2 is started, the air enters the RTO furnace 1 through the combustion pipeline through the combustion air adjusting valve 3 and the burner 10, the ignition is allowed, the first emptying valve 18 and the second emptying valve 20 are closed, the natural gas is supplied by the natural gas storage tank 11, the first ignition, the ignition transformer 22 is powered on, the two ignition gas valves 16 are opened, the natural gas enters the RTO furnace 1 through the burner 10 through the natural gas auxiliary pipeline 13, as long as one of the two flame detectors 21 detects a flame signal, it means that the ignition is successful, the ignition transformer 22 is powered off, the two main gas valves 6 are opened, the two ignition gas valves 16 are closed, the natural gas only enters the RTO furnace 1 through the natural gas main pipeline 12 through the burner 10, and the subsequent work can be carried out;

[0035] First ignition, ignition transformer 22 is powered on, open two ignition gas valve 16, if two flame detectors 21 can not detect the flame signal, ignition failure count, close ignition transformer 22 and two ignition gas valve 16, if the number of ignition failure is less than or equal to 3 times, the ignition transformer 22 is powered on again, and the two ignition gas valves 16 are opened; if the number of ignition failure is greater than 3 times, the average temperature of the combustion chamber A and the combustion chamber B of the RTO furnace 1 is less than 790 DEG C, the system is purged for 180s, the ignition fails, and the combustion air fan 2 is closed.

[0036] Figure 3 The sequence diagram is for the ignition control system of the existing RTO furnace, the Honeywell EC7810A is used as the ignition controller, and the EC7810A controller does not reasonably adjust the control scheme according to the installation position of the field device; because the distance between the natural gas regulating valve and the burner is 8m, the spark plug ignition arc time is short, the natural gas does not reach the spark plug to end the discharge arc, causing the ignition failure. And the utility model RTO furnace ignition system reasonably optimizes the ignition control scheme, installs the natural gas regulating valve close to the burner (2m away from the burner), prolongs the spark plug discharge arc time, starts the combustion air fan in advance during ignition, and opens the combustion air regulating valve to the ignition position (25%), to meet the control principle of "three simultaneously".

[0037] It should be noted that, in the present document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0038] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made hereto without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A kind of ignition system of promoting RTO furnace flame rigidity, including RTO furnace (1), combustion-supporting fan (2), burner (10) and natural gas supply equipment (11), it is characterized in that, The RTO furnace (1) is provided with the burner (10) on the outer top, the combustion fan (2) is connected with the upper end of the burner (10) through the combustion pipeline, and the upper end of the burner (10) is connected with the natural gas supply device (11) through the natural gas main pipeline (12); the natural gas main pipeline (12) is sequentially provided with a first natural gas pressure transmitter (7), two main gas valves (6), a second natural gas pressure transmitter (5) and a natural gas regulating valve (15); the natural gas regulating valve (15) is connected with the combustion pipeline through a pipeline, and the distance between the natural gas regulating valve (15) and the burner (10) is 2 m; One end of the natural gas auxiliary pipeline (13) is also connected with the upper end of the burner (10), and the other end of the natural gas auxiliary pipeline (13) is connected with the natural gas main pipeline (12); the first natural gas pressure transmitter (7) is arranged at the interface between the natural gas main pipeline (12) and the natural gas auxiliary pipeline (13); one end of the emptying pipeline I (17) is connected with the natural gas main pipeline (12) between the two main gas valves (6), and the first emptying valve (18) is arranged on the emptying pipeline I (17); two ignition gas valves (16) are arranged on the natural gas auxiliary pipeline (13), the emptying pipeline II (19) is connected with the natural gas auxiliary pipeline (13) between the two ignition gas valves (16), and the second emptying valve (20) is arranged on the emptying pipeline II (19); the other end of the emptying pipeline I (17) is connected with the emptying pipeline II (19); Two flame detectors (21) are arranged on the inner top of the RTO furnace (1), and an ignition transformer (22) is further arranged on the outer upper end of the RTO furnace (1); the two main gas valves (6), the first emptying valve (18), the two ignition gas valves (16), the second emptying valve (20) and the ignition transformer (22) constitute an execution module, the two flame detectors (21), the first natural gas pressure transmitter (7) and the second natural gas pressure transmitter (5) constitute a sensor module, and the execution module, the sensor module and a control module constitute an SIS ignition control system (4).

2. The ignition system of claim 1, wherein, The RTO furnace (1) is internally divided into an A combustion chamber and a B combustion chamber; the combustion air regulating valve (3) is arranged on the combustion pipeline connected with the upper end of the burner (10) of the combustion fan (2), and the combustion air regulating valve (3) is an angular travel pneumatic control butterfly valve; the natural gas regulating valve (15) is a mechanical pressure regulating valve.

3. The ignition system of claim 1, wherein the flame rigidity of the RTO is improved. The emptying valve (14) is further arranged on the emptying pipeline II (19).

4. The ignition system of claim 1, wherein, A pressure reducing valve (9), a locking valve (23) and a Y-shaped filter (8) are sequentially arranged on the natural gas main pipeline (12) between the natural gas supply device (11) and the first natural gas pressure transmitter (7).

5. The ignition system of claim 1, wherein, The volume ratio of the natural gas supplied by the natural gas supply device (11) to the air input by the combustion fan (2) is 10:

1.

6. The ignition system of claim 2, wherein, The combustion air regulating valve (3), the two main gas valves (6), the two ignition gas valves (16), the first exhaust valve (18) and the second exhaust valve (20) are all powered by instrument air.

7. The ignition system of claim 1, wherein the flame rigidity of the RTO is improved. A safety isolation barrier is arranged between the control module and the execution module.

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