A direct-fired waste gas incineration system process

Abstract

The invention discloses a direct-fired waste gas incineration system process, in which the waste gas first enters a buffer tank for stabilization through an online combustible gas concentration monitor; when the online combustible gas concentration monitor detects that the waste gas concentration is high and within the load adjustment ratio allowed by the burner, the second valve is closed, and the waste gas directly enters the burner through the first valve; when it is detected that the waste gas concentration is lower than the allowed value, the waste gas enters the combustion system in two ways, one way enters the burner through the first valve, and the other way directly enters the incinerator through the second valve, and at the same time, the amount of auxiliary fuel gas and the amount of combustion-supporting air are adjusted to achieve complete decomposition of the waste gas; the decomposed high-temperature flue gas is treated by a heat recovery system and a flue gas post-treatment system to obtain purified gas, which is discharged through a purified gas pipeline; the invention targets waste gas with large fluctuations in waste gas concentration, combines the combustion characteristics of waste gas with different concentrations, optimizes the waste gas combustion organization, safely and efficiently treats waste gas with a large fluctuation range of operating conditions, and achieves complete decomposition of waste gas under any operating condition and up-to-standard emission.

Description

Technical Field

[0001] The invention belongs to the technical field of waste gas treatment, and in particular relates to a direct-fired waste gas incineration system process. Background Art

[0002] In the field of waste gas treatment, compared with other waste gas treatment methods, incineration is currently the most common and most thorough treatment technology based on its perfect system process. The mechanism of thermal incineration is to convert waste gas into CO2 and H2O emissions through oxidation, thermal cracking and thermal decomposition, mainly including direct combustion, regenerative thermal oxidation and catalytic oxidation. Depending on the concentration of waste gas, the treatment method is also different from the perspective of economy and reliability. Usually, when the concentration of combustible components in the waste gas is >10g / m 3 , direct combustion is adopted, the concentration is 3~10g / m 3 Using catalytic oxidation method, the concentration is 1 ~ 6g / m 3 The regenerative thermal oxidation method is adopted.

[0003] Regardless of the treatment method, the exhaust gas concentration must be kept basically stable to ensure the safety of the treatment process and a high purification rate. However, in the actual operation process, due to the particularity of the process, the concentration of combustibles in the exhaust gas fluctuates greatly, ranging from 0 to 40% (about 0-600g / m 3 ), sometimes even more volatile, and it will frequently occur in conditions where the exhaust gas concentration is extremely low or even zero or extremely high, and it is unpredictable. For this type of condition, since the high exhaust gas concentration far exceeds the suitable concentration range of catalytic oxidation and regenerative thermal oxidation, it will seriously overheat during operation, causing equipment damage. Therefore, these two treatment methods cannot be used, and only direct combustion incineration can be considered.

[0004] When direct combustion is used, the furnace temperature of the common waste gas incinerator is maintained between 850-1100℃. The waste gas needs to be completely decomposed while the combustion is stable. Usually, the location where the waste gas enters the incinerator is different according to its calorific value, and even the type of burner used is different. According to HG 20706-2013 "Design Specifications for Waste Incineration and Disposal Engineering in Chemical Construction Projects", the calorific value of gaseous chemical waste to maintain stable incineration must reach 4200kJ / Nm 3 Above, when the calorific value is less than 4200kJ / Nm 3Auxiliary fuel should be used when the purging gas with extremely low calorific value and containing a large amount of inert gas is used. Usually, the waste gas is directly introduced into the incinerator body to serve as cooling air; the remaining higher calorific value gas enters different positions of the burner according to the calorific value to achieve low-nitrogen graded combustion. In order to ensure flame stability and avoid safety problems such as flameout and flashback, conventional incinerator burners require a certain adjustment ratio, usually 10:1, and special burners are used to maintain flame stability for low calorific value gases.

[0005] However, for a gas source with such a large concentration fluctuation, it is necessary to take into account both the high and low concentration values, which poses a huge challenge to the combustion organization design of the incinerator. When the concentration is at the upper limit, its calorific value is high, and its furnace temperature near the theoretical air equivalent ratio will exceed the design temperature, and it is necessary to reduce the furnace temperature by increasing the air supply volume; and when the concentration of combustible gas is low, especially when the concentration is 0, even in the case of combustion-supporting fuel gas, when the exhaust gas contains a large amount of exhaust gas such as 80%-97% nitrogen and carbon dioxide, this exhaust gas has a large amount of inert gas. The inhibitory effect on combustion seriously affects the stability of combustion. Therefore, it is difficult for conventional combustion methods to ensure safe and stable combustion under all working conditions, and the exhaust gas destruction rate cannot meet the requirements. Summary of the invention

[0006] In order to solve the technical bottlenecks mentioned in the above background content, the first purpose of the present invention is to provide a direct-fired waste gas incineration system; the second purpose of the present invention is to provide a direct-fired waste gas incineration system process; the present invention targets waste gas with large fluctuations in waste gas concentration, considers the overall safety and reliability of the system, combines the combustion characteristics of waste gas with different concentrations, optimizes the waste gas combustion organization, and safely and efficiently processes waste gas with a large fluctuation range of operating conditions, so as to achieve complete decomposition of waste gas under any operating conditions and meet emission standards.

[0007] The technical solution adopted by the present invention to solve the technical problem is:

[0008] A direct-fired waste gas incineration system, comprising a concentration monitoring and gas source stabilization system, a combustion system, a waste heat recovery system and a flue gas post-treatment system in sequence; the concentration monitoring and gas source stabilization system is used to monitor the waste gas concentration and stabilize the gas; the waste heat recovery system is used to recover heat from the high-temperature gas coming out of the combustion system; the flue gas post-treatment system is used to further purify the incineration gas;

[0009] The concentration monitoring and gas source stabilization system comprises an online combustible gas concentration monitor and a buffer tank, the buffer tank is connected to a waste gas main valve, the waste gas main valve is connected to two valves in parallel, namely a first valve (4) and a second valve (5), and the online combustible gas concentration monitor is electrically connected to the second valve;

[0010] The combustion system includes a burner and an incinerator, wherein the burner is arranged on the incinerator; wherein the burner is connected to a first valve pipeline, and the incinerator is connected to a second valve pipeline; the burner is externally connected to an auxiliary fuel gas pipeline and a combustion-supporting air pipeline, and the combustion-supporting air pipeline is respectively connected to the burner and the incinerator through a blower; and the flue gas post-treatment system is connected to a purified gas pipeline.

[0011] The present invention targets waste gas with large fluctuations in waste gas concentration. Taking the overall safety and reliability of the system into consideration, the present invention combines the combustion characteristics of waste gas with different concentrations, optimizes the waste gas combustion organization, and safely and efficiently processes waste gas with a large fluctuation range of operating conditions, so as to achieve complete decomposition of waste gas under any operating condition and meet emission standards.

[0012] As a preferred technical solution of the present application, the purified gas pipeline is connected to the incinerator via the first induced draft fan.

[0013] As a preferred technical solution of the present application, the purified gas pipeline is further provided with a second induced draft fan, the second induced draft fan is arranged in parallel with the first induced draft fan, and the purified gas is discharged from the system through the second induced draft fan.

[0014] As a preferred technical solution of the present application, the burner is a low-nitrogen burner.

[0015] As a preferred technical solution of the present application, the waste heat recovery system is provided with one or more of a waste heat boiler, a heat exchanger, an economizer, and an air preheater.

[0016] Preferably, the heat exchanger is the heat exchanger in the specific implementation method of patent ZL2011102269485.

[0017] As the preferred technical solution of the present application, the flue gas post-treatment system is provided with one or more of a desulfurization device, a denitrification device, an alkali washing device and a dust removal device. The flue gas post-treatment system selects a treatment device according to the type of waste gas. If desulfurization treatment is required, a desulfurization tower can be selected for desulfurization treatment; if denitrification is required, an SCR reactor can be selected; if desulfurization and denitrification are required, a combined desulfurization and denitrification treatment can be selected.

[0018] Preferably, the desulfurization device, denitrification device, alkali washing device and dust removal device are arranged in an integrated manner or separately.

[0019] A direct-fired waste gas incineration system process comprises the following steps: the waste gas first enters a buffer tank for stabilization via an online combustible gas concentration monitor; when the online combustible gas concentration monitor detects that the waste gas concentration is high and within the load adjustment ratio allowed by the burner, the second valve is closed and the waste gas directly enters the burner via the first valve; when it is detected that the waste gas concentration is lower than the allowed value, the waste gas enters the combustion system in two ways, one way enters the burner via the first valve, and the other way enters the incinerator directly via the second valve, and at the same time, the amount of auxiliary fuel gas and the amount of combustion-supporting air are adjusted to achieve complete decomposition of the waste gas; the decomposed high-temperature flue gas is treated by a heat recovery system and a flue gas post-treatment system to obtain purified gas, which is discharged via a purified gas pipeline.

[0020] As a preferred technical solution of the present application, a portion of the purified gas is introduced into the incinerator through the first induced draft fan, and the other portion is discharged from the system through the second induced draft fan.

[0021] Beneficial Effects

[0022] The direct-fired waste gas incineration system and process provided by the present invention has the following beneficial effects compared with the prior art:

[0023] (1) The present invention targets waste gas with large fluctuations in waste gas concentration. Considering the overall safety and reliability of the system, the present invention combines the combustion characteristics of waste gas with different concentrations to optimize the waste gas combustion organization, safely and efficiently treats waste gas with a large fluctuation range of working conditions, and achieves complete decomposition of waste gas under any working condition and meets the emission standards; BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a direct-fired waste gas incineration system of the present invention;

[0025] Among them, 1-online monitor of combustible gas concentration; 2-buffer tank; 3-main exhaust valve; 4-first valve; 5-second valve; 6-burner; 7-blower; 8-incinerator; 9-waste heat recovery system; 10-flue gas post-treatment system; 11-first induced draft fan; 12-second induced draft fan. DETAILED DESCRIPTION

[0026] In order to make the content of the present invention more easily understood, the present invention is further described in detail below in conjunction with the embodiments. Now the present invention is further described in detail in conjunction with the accompanying drawings. These drawings are all simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, so they only show the composition related to the present invention.

[0027] Example 1

[0028] refer to Figure 1A direct-fired waste gas incineration system is provided with a concentration monitoring and gas source stabilization system, a combustion system, a waste heat recovery system and a flue gas post-treatment system in sequence; the concentration monitoring and gas source stabilization system is used to monitor the waste gas concentration and stabilize the gas; the waste heat recovery system 9 is used to recover heat from the high-temperature gas coming out of the combustion system; the flue gas post-treatment system 10 is used to further purify the incineration gas;

[0029] The concentration monitoring and gas source stabilization system comprises an online combustible gas concentration monitor 1 and a buffer tank 2, the buffer tank 2 is connected to a waste gas main valve 3, the waste gas main valve 3 is connected to two valves in parallel, namely a first valve 4 and a second valve 5, the online combustible gas concentration monitor 1 is electrically connected to the second valve 5;

[0030] The combustion system includes a burner 6 and an incinerator 8, wherein the burner 6 is arranged on the incinerator 8; wherein the burner 6 is connected to the first valve 4 pipeline, and the incinerator 8 is connected to the second valve 5 pipeline; the burner 6 is externally connected to an auxiliary fuel gas pipeline and a combustion-supporting air pipeline, and the combustion-supporting air pipeline is respectively connected to the burner 6 and the incinerator 8 through a blower 7; the flue gas post-treatment system 10 is connected to a purified gas pipeline.

[0031] The incineration process using the above-mentioned direct-fired waste gas incineration system, such as Figure 1 As shown: the exhaust gas first enters the buffer tank 2 for stabilization through the combustible gas online concentration monitor 1; when the combustible gas concentration online monitor 1 detects that the exhaust gas concentration is high and within the allowable load adjustment ratio of the burner 6, the second valve 5 is closed, and the exhaust gas directly enters the burner 6 through the first valve 4; when it is detected that the exhaust gas concentration is lower than the allowable value, the exhaust gas enters the combustion system in two ways, one way enters the burner 6 through the first valve 4, and the other way directly enters the incinerator 8 through the second valve 5, and at the same time adjusts the auxiliary fuel gas volume and the combustion air volume to achieve complete decomposition of the exhaust gas; the decomposed high-temperature flue gas is treated by the heat recovery system 9 and the flue gas post-treatment system 10 to obtain purified gas, which is discharged through the purified gas pipeline.

[0032] Example 2

[0033] A direct-fired waste gas incineration system, comprising a concentration monitoring and gas source stabilization system, a combustion system, a waste heat recovery system and a flue gas post-treatment system in sequence; the concentration monitoring and gas source stabilization system is used to monitor the waste gas concentration and stabilize the gas; the waste heat recovery system 9 is used to recover heat from the high-temperature gas coming out of the combustion system; the flue gas post-treatment system 10 is used to further purify the incineration gas; the concentration monitoring and gas source stabilization system comprises a combustible gas concentration online monitor 1 and a buffer tank 2, the buffer tank 2 is connected to a waste gas main valve 3, the waste gas main valve 3 is connected to two valves in parallel, namely a first valve 4 and a second valve 5, the combustible gas concentration online monitor 1 is electrically connected to the second valve 5;

[0034] The combustion system includes a burner 6 and an incinerator 8, wherein the burner 6 is arranged on the incinerator 8; wherein the burner 6 is connected to the first valve 4 pipeline, and the incinerator 8 is connected to the second valve 5 pipeline; the burner 6 is externally connected to an auxiliary fuel gas pipeline and a combustion-supporting air pipeline, and the combustion-supporting air pipeline is respectively connected to the burner 6 and the incinerator 8 via a blower 7; the flue gas post-treatment system 10 is connected to a purified gas pipeline; the purified gas pipeline is connected to the incinerator 8 via a first induced draft fan 11; the purified gas pipeline is also provided with a second induced draft fan 12, and the second induced draft fan 12 is arranged in parallel with the first induced draft fan 11, and the purified gas is discharged from the system via the second induced draft fan 12.

[0035] The waste heat recovery system 9 is provided with one or more of a waste heat boiler, a heat exchanger, an economizer, and an air preheater for waste heat recovery. For example, the heat exchanger can use the heat exchanger in the specific implementation method of patent ZL2011102269485.

[0036] Among them, according to the characteristics of the exhaust gas, the flue gas post-treatment system is equipped with one or more of a desulfurization device, a denitrification device, an alkali washing device and a dust removal device. The flue gas post-treatment system can be set up in an integrated manner or in a separate manner.

[0037] In other embodiments, the burner may be a low nitrogen burner.

[0038] The process of the above direct-fired waste gas incineration system is as follows: Figure 1As shown, the exhaust gas enters the buffer tank 2 after passing through the combustible gas online concentration monitor 1. When the concentration fluctuates slightly and for a short time, the buffer tank can play a certain pressure stabilizing role in combustion; the exhaust gas can be divided into two paths to enter the combustion system after passing through the exhaust gas main valve 3, one path enters the burner 6 through the first valve 4, and the other path directly enters the incinerator 8 through the second valve 5. The second valve 5 is interlocked with the combustible gas online concentration monitor 1. When the monitored exhaust gas concentration is high and within the allowable load adjustment ratio of the burner 6, the second valve 5 is closed and the exhaust gas directly enters the burner 6. When the monitored exhaust gas concentration is lower than the allowable value, the second valve 5 is opened to divert a part of the exhaust gas into the incinerator 8. While ensuring the minimum flow rate of the low calorific value exhaust gas in the burner 6 without flashback, the influence of the inert gas on the combustion stability is minimized. At the same time, according to the combustion temperature of the incinerator 8 and the flue gas temperature and composition, the amount of auxiliary fuel gas and the amount of combustion-supporting air are adjusted. The combustion-supporting air enters the burner 6 and the incinerator 8 in stages through the blower 7, so as to realize the optimal combustion organization control. The exhaust gas and air are fully mixed and burned in the high temperature environment of the incinerator 8 and stay for a sufficient time, thereby realizing safe and complete decomposition of the exhaust gas under all working conditions.

[0039] After the high-temperature flue gas passes through the waste heat recovery system 9 (such as waste heat boilers, heat exchangers, economizers, air preheaters, etc.) and the flue gas post-treatment system 10 (treated according to the characteristics of the exhaust gas, such as desulfurization and denitrification, alkali washing and dust removal, etc.), the purified gas is discharged through the second induced draft fan 12; at the same time, when incinerating high-calorific value gases, the air volume of the first induced draft fan 11 can be adjusted according to the furnace temperature, and a part of the low-temperature purified gas can be introduced into the incinerator body. While lowering the furnace temperature, the oxygen content in the flue gas can be reduced, ultimately achieving optimized combustion and achieving safe and standard exhaust of exhaust gases.

[0040] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0041] The meaning of "and / or" described in this application means that the situations where each exists alone or both exist at the same time are included.

[0042] The term “connection” as used in this application may mean a direct connection between components or an indirect connection between components via other components.

[0043] The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the inventive concept, changes and advantages that can be thought of by those skilled in the art are included in the present invention and are protected by the attached claims.

Claims

1. A combustion process of a direct-fired waste gas incineration system, characterized in that: The direct-fired waste gas incineration system comprises a concentration monitoring and gas source stabilization system, a combustion system, a waste heat recovery system and a flue gas post-treatment system in sequence; the concentration monitoring and gas source stabilization system is used to monitor the waste gas concentration and stabilize the gas; the waste heat recovery system (9) is used to recover heat from the high-temperature gas coming out of the combustion system; the flue gas post-treatment system (10) is used to further purify the incineration gas; The concentration monitoring and gas source stabilization system comprises an online combustible gas concentration monitor (1) and a buffer tank (2), wherein the buffer tank (2) is connected to a waste gas main valve (3), and the waste gas main valve (3) is connected to two valves in parallel, namely a first valve (4) and a second valve (5), and the online combustible gas concentration monitor (1) is electrically connected to the second valve (5); The combustion system comprises a burner (6) and an incinerator (8), wherein the burner (6) is arranged on the incinerator (8); wherein the burner (6) is connected to a first valve (4) pipeline, and the incinerator (8) is connected to a second valve (5) pipeline; the burner (6) is externally connected to an auxiliary fuel gas pipeline and a combustion-supporting air pipeline, and the combustion-supporting air pipeline is respectively connected to the burner (6) and the incinerator (8) via a blower (7); The flue gas post-treatment system (10) is connected to a purified gas pipeline; The combustion process of the direct-fired waste gas incineration system comprises the following steps: the waste gas first enters the buffer tank (2) through the combustible gas concentration online monitor (1) to stabilize; when the combustible gas concentration online monitor (1) detects that the waste gas concentration is high and within the load adjustment ratio allowed by the burner (6), the second valve (5) is closed, and the waste gas directly enters the burner (6) through the first valve (4); when the waste gas concentration is detected to be lower than the allowed value, the waste gas enters the combustion system in two ways, one way enters the burner (6) through the first valve (4), and the other way enters the incinerator (8) directly through the second valve (5), and at the same time, the amount of auxiliary fuel gas and the amount of combustion-supporting air are adjusted to achieve complete decomposition of the waste gas; the high-temperature flue gas after decomposition is treated by the waste heat recovery system (9) and the flue gas post-treatment system (10) to obtain purified gas, which is discharged through the purified gas pipeline.

2. The incineration process of a direct-fired waste gas incineration system according to claim 1 is characterized in that: The purified gas pipeline is connected to the incinerator (8) via the first induced draft fan (11).

3. The incineration process of a direct-fired waste gas incineration system according to claim 2 is characterized in that: The purified air pipeline is further provided with a second induced draft fan (12), the second induced draft fan (12) being arranged in parallel with the first induced draft fan (11), and the purified air is discharged from the system via the second induced draft fan (12).

4. The incineration process of a direct-fired waste gas incineration system according to any one of claims 1 to 3, characterized in that: The burner is a low-nitrogen burner.

5. The incineration process of a direct-fired waste gas incineration system according to any one of claims 1 to 3, characterized in that: The waste heat recovery system (9) is provided with one or more of a waste heat boiler, a heat exchanger, an economizer, and an air preheater.

6. The incineration process of a direct-fired waste gas incineration system according to any one of claims 1 to 3, characterized in that: The flue gas post-treatment system (10) is provided with one or more of a desulfurization device, a denitrification device, an alkali washing device and a dust removal device.

7. The incineration process of a direct-fired waste gas incineration system according to claim 6, characterized in that: The desulfurization device, denitration device, alkali washing device and dust removal device are arranged in one piece or in separate pieces.

8. The incineration process of a direct-fired waste gas incineration system according to claim 3 is characterized in that: A portion of the purified gas is introduced into the incinerator (8) via the first induced draft fan (11), and the other portion is discharged from the system via the second induced draft fan (12).

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