Catalyst-free non-ammonia denitration system and method and application

Abstract

The invention relates to the field of flue gas denitration, and discloses a catalyst-free non-ammonia denitration system and method and application. The method comprises the following steps: atomizing a non-ammonia bio-based denitration reducing agent through at least six double-fluid spray guns, and spraying the atomized non-ammonia bio-based denitration reducing agent into a hearth convection section of the ethylene cracking furnace so as to be in contact with flue gas of the ethylene cracking furnace for a reduction reaction, wherein the non-ammonia bio-based denitration reducing agent comprises the following components in parts by weight: 4 parts of biomass lysis buffer, 0.5-1 part of cyanuric acid, 0.5-1 part of demineralized water and 0.5-1 part of ethylene glycol; the conditions of the reduction reaction are as follows: the temperature is 600-1100 DEG C, and the time is 0.2-0.4 s. According to the method, the reduction reaction process can be completed within a short residence time, the concentration of NOX in discharged flue gas is effectively reduced, and high denitration efficiency is obtained.

Description

Technical Field

[0001] The present invention relates to the field of flue gas denitrification, and in particular to a catalyst-free non-ammonia denitrification system, method and application. Background Art

[0002] The existing flue gas catalyst-free (non-catalytic reduction) denitrification technology (SNCR) uses amino groups (urea or ammonia water) as a reducing agent, which has no application cases in ethylene cracking furnaces.

[0003] The reaction temperature range of amino SNCR is 850-1150℃. Under the conditions of specific temperature and oxygen, it can selectively convert NO in the flue gas into x Reduction to N2 and H2O is one of the earliest and most mature technologies used both domestically and internationally. Reaction temperature determines the upper limit of denitration efficiency, while the residence time of the amino reducing agent and its degree of mixing with the flue gas directly determine the efficiency of achieving the upper limit of denitration efficiency at a given temperature. Key requirements for amino SNCR are a flue gas temperature of 850°C-950°C, a residence time of 0.5-1.0s, and a degree of mixing that achieves seamless coverage.

[0004] The furnace area of ​​the ethylene cracking furnace suitable for implementing SNCR is the convection section (the empty section above the lower mixing preheater), with a flue gas temperature of 800-850°C. The flue gas residence time in this temperature range is 0.2-0.4s. If amino reducing agents are used for denitrification, the efficiency will be extremely low and have no practical application value. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problem that the existing denitration system and method are not applicable to the flue gas of ethylene cracking furnace and have low denitration efficiency.

[0006] In order to achieve the above object, the first aspect of the present invention provides a catalyst-free non-ammonia denitrification method, the method comprising:

[0007] A non-ammonia bio-based denitrification reducing agent is atomized by at least six dual-fluid spray guns and injected into a convection section of a furnace of an ethylene cracking furnace to contact with flue gas of the ethylene cracking furnace to perform a reduction reaction;

[0008] The non-ammonia bio-based denitrification reducing agent comprises: 4 parts by weight of biomass pyrolysis liquid, 0.5-1 parts by weight of cyanuric acid, 0.5-1 parts by weight of deionized water and 0.5-1 parts by weight of ethylene glycol;

[0009] The reduction reaction conditions include: temperature of 600-1100° C. and time of 0.2-0.4 s.

[0010] A second aspect of the present invention provides a catalyst-free, non-ammonia denitrification system, comprising a reducing agent storage module, a distribution module, an injection module, and a reaction module connected in sequence; wherein:

[0011] The reaction module includes an ethylene cracking furnace, and at least six injection ports are horizontally and equidistantly arranged on the side wall of the convection section of the furnace of the ethylene cracking furnace;

[0012] The injection module is used to atomize the non-ammonia bio-based denitrification reducing agent and inject it into the furnace of the ethylene cracking furnace; the injection module includes an injector group, which includes at least 6 dual-fluid spray guns, and the dual-fluid spray guns are arranged at the injection port.

[0013] The third aspect of the present invention provides the use of the catalyst-free non-ammonia denitrification system described in the first aspect in the denitrification of flue gas from an ethylene cracking furnace.

[0014] Through the above technical solution, the catalyst-free non-ammonia denitrification system and method provided by the present invention have the following advantages:

[0015] (1) The ethylene cracking furnace flue gas can achieve deep denitrification by implementing non-ammonia SNCR, which can effectively reduce the NO in the exhaust flue gas. X The optimal concentration can be reduced to 30 mg / m 3 the following;

[0016] (2) The flue gas temperature window is widened, and the non-ammonia bio-based denitrification reductant can maintain a high denitrification efficiency when the flue gas temperature is below 800°C, and the effective flue gas temperature window is 600-1100°C;

[0017] (3) By setting up a specific dual-fluid spray gun and combining it with the narrow space of the convection section of the ethylene cracking furnace, the reduction reaction process can be completed within a relatively short residence time (0.2-0.4s) and a higher denitrification efficiency can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a system and process flow chart of a catalyst-free non-ammonia denitrification method according to a specific embodiment of the present invention. DETAILED DESCRIPTION

[0019] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0020] As mentioned above, the first aspect of the present invention provides a catalyst-free non-ammonia denitrification method, the method comprising:

[0021] A non-ammonia bio-based denitrification reducing agent is atomized by at least six dual-fluid spray guns and injected into a convection section of a furnace of an ethylene cracking furnace to contact with flue gas of the ethylene cracking furnace to perform a reduction reaction;

[0022] The non-ammonia bio-based denitrification reducing agent comprises: 4 parts by weight of biomass pyrolysis liquid, 0.5-1 parts by weight of cyanuric acid, 0.5-1 parts by weight of deionized water and 0.5-1 parts by weight of ethylene glycol;

[0023] The reduction reaction conditions include: temperature of 600-1100° C. and time of 0.2-0.4 s.

[0024] According to some embodiments of the present invention, preferably, any of the two-fluid spray guns is a post-mix two-fluid spray gun; the number of nozzle through-holes of any of the two-fluid spray guns is 5-7, and the diameter of any of the through-holes is 1-2 mm. Using a two-fluid spray gun that meets these requirements is conducive to further improving the denitrification effect of flue gas.

[0025] According to some embodiments of the present invention, preferably, the spray angle of any of the two-fluid spray guns is 65-75°, and the horizontal spray distance is 2.2-3.5m, preferably 2.2-3.2m. The two-fluid spray guns of the above preferred embodiments have both penetrating power and atomizing effect, which is conducive to further improving the denitrification effect of flue gas.

[0026] According to some embodiments of the present invention, preferably, the injection flow rate of any of the two-fluid spray guns is not less than 15 L / h, preferably 15-30 L / h. Using a two-fluid spray gun that meets the above requirements is conducive to further improving the denitrification effect of flue gas.

[0027] According to some embodiments of the present invention, the non-ammonia bio-based denitrification reducing agent includes: 4 parts by weight of biomass pyrolysis liquid, 0.5-1 parts by weight of cyanuric acid, 0.5-1 parts by weight of deionized water and 0.5-1 parts by weight of ethylene glycol. Wherein, the biomass pyrolysis liquid (Bio-oil) is a mixture composed of various degradation products of cellulose, hemicellulose and lignin that are rapidly pyrolyzed under air-tight conditions. The density of the biomass pyrolysis oil (biomass pyrolysis liquid) used in the present invention is 1.15-1.20 g / mL, containing 6.7-8.9 wt% of soluble solids, 12-17 μg / L of tar, 6.9-18.4 wt% of total acid, 0.63-0.92 mg / L of volatile phenols, 0.36-0.75 mg / L of ketones, and 0.20-0.35 mg / L of alcohols. The relative contents of some components are shown in Table 1:

[0028] Table 1

[0029] Components Relative content Components Relative content Formic acid 4.8 3-Methyl-2-cyclopentenone 1.4 Acetic acid 47.9 phenol 2.8 1-Hydroxy-2-propanone 9.9 2-Hydroxy-3-methylcyclopentenone 2.1 Propionic acid 9.9 2-Methylphenol 1 1-Hydroxy-2-propanone 2.2 4-Methylphenol 4.8 Butyric acid 3.6 4-Methoxyphenol 1.5 Furfural 4 3-Ethylphenol 1 Furfuryl alcohol 1.9 3-Ethyl-2-hydroxy-2-cyclopentenone 0.6 Butyrolactone 1.8 2,6-dimethoxyphenol 0.7 2-Methyl-2-cyclopentenone 0.7 4-Ethyl-2-methoxyphenol 0.4

[0030] According to some embodiments of the present invention, preferably, the non-ammonia bio-based denitrification reductant is prepared by a method comprising the following steps: stirring and mixing 4 parts by weight of biomass pyrolysis liquid, 0.5-1 parts by weight of cyanuric acid, 0.5-1 parts by weight of desalted water and 0.5-1 parts by weight of ethylene glycol for 1-2 hours to obtain an emulsion, and then heating the emulsion to a constant temperature of above 70°C for 2-3 hours.

[0031] According to some embodiments of the present invention, preferably, the flow rate of the non-ammonia bio-based denitrification reducing agent is 20-40 L / h.

[0032] According to some embodiments of the present invention, the non-ammonia bio-based denitrification reducing agent is preferably provided in the form of an aqueous solution, wherein the aqueous solution is obtained by mixing desalted water with the non-ammonia bio-based denitrification reducing agent, and the aqueous solution has an aqueous-to-agent ratio of 2-3:1. The "aqueous-to-agent ratio" refers to the volumetric flow ratio of the desalted water to the non-ammonia bio-based denitrification reducing agent.

[0033] According to some embodiments of the present invention, preferably, the temperature of the reduction reaction is 650-900°C, preferably 700-850°C, more preferably 800-850°C. x The reduction reaction of NOx is carried out in a specific reaction temperature range, which is relatively narrow, 850℃-1150℃. If the temperature is lower than 850℃, the NH3 reaction will be incomplete, forming the so-called "ammonia breakthrough", reducing NOx x The removal rate is very low, resulting in extremely low flue gas denitrification efficiency. However, the present invention uses a specific non-ammonia bio-based denitrification reducing agent with a wider flue gas temperature window. This can effectively utilize the flue gas temperature and flue gas residence time in the convection section of the ethylene cracking furnace, better utilizing the denitrification effect of the non-ammonia bio-based denitrification reducing agent injected into the convection section. This achieves ultra-clean flue gas emissions without changing the cracking furnace process flow and module configuration. High flue gas denitrification efficiency can be achieved when the flue gas temperature is below 850°C, and even at a flue gas temperature below 800°C, it can still maintain a high denitrification efficiency.

[0034] According to some embodiments of the present invention, preferably, the concentration of nitrogen oxides in the flue gas of the ethylene cracking furnace is 80-90 mg / m 3 ; The concentration of SO2 is 0-5mg / m 3 .

[0035] According to some embodiments of the present invention, preferably, the temperature of the flue gas from the ethylene cracking furnace is 650-900°C, preferably 700-850°C, and more preferably 800-850°C.

[0036] A second aspect of the present invention provides a catalyst-free, non-ammonia denitrification system, comprising a reducing agent storage module, a distribution module, an injection module, and a reaction module connected in sequence; wherein:

[0037] The reaction module includes an ethylene cracking furnace, and at least six injection ports are horizontally and equidistantly arranged on the side wall of the convection section of the furnace of the ethylene cracking furnace;

[0038] The injection module is used to atomize the non-ammonia bio-based denitrification reducing agent and inject it into the furnace of the ethylene cracking furnace; the injection module includes an injector group, which includes at least 6 dual-fluid spray guns, and the dual-fluid spray guns are arranged at the injection port.

[0039] According to some embodiments of the present invention, each of the two-fluid spray guns is disposed in one-to-one correspondence with each of the injection ports.

[0040] According to some embodiments of the present invention, the characteristic parameters satisfied by any of the dual-fluid spray guns are as previously described and are not further elaborated here. Using a dual-fluid spray gun that meets these requirements facilitates both the penetration and atomization of the injected non-ammonia bio-based denitrification reductant, further promoting its contact with the flue gas and achieving a better flue gas denitrification effect.

[0041] According to some embodiments of the present invention, the reductant storage module is used to provide a non-ammonia bio-based denitrification reductant. Preferably, the reductant storage module includes a reductant storage tank and a dosing pump connected in sequence.

[0042] According to some embodiments of the present invention, preferably, a return line is further provided between the reducing agent storage tank and the dosing pump.

[0043] According to some embodiments of the present invention, preferably, the system further comprises a dilution water module, wherein the dilution water module is configured to provide the distribution module with an aqueous solution obtained by mixing desalted water and a non-ammonia bio-based denitrification reducing agent.

[0044] According to some embodiments of the present invention, preferably, the dilution water module includes a water tank, a water pump and a static mixer; the input end of the water pump is connected to the water tank, and the output end of the water pump is connected to the input end of the static mixer; the output end of the static mixer is connected to the input end of the distribution module.

[0045] According to some embodiments of the present invention, preferably, the output end of the reductant storage module is connected to the input end of the static mixer. The static mixer is used to mix the desalted water from the water tank with the non-ammonia bio-based denitrification reductant from the reductant storage module to obtain the aqueous solution, and provide the aqueous solution to the distribution module.

[0046] According to some embodiments of the present invention, the injection module preferably further includes a gasification air device, wherein the input end of the injector group is connected to the output end of the distribution module and the gasification air device via pipelines. The gasification air device is used to provide compressed air to the injector group to atomize the non-ammonia bio-based denitrification reductant, which is then injected into the convection section of the furnace of the ethylene cracking furnace through the injector group to contact the ethylene cracking furnace flue gas for a reduction reaction.

[0047] According to some embodiments of the present invention, the system preferably further includes a monitoring component and a metering component, wherein the monitoring component includes multiple valves and multiple pressure gauges, and the metering component includes multiple flow meters. The monitoring component is used to control the opening and closing of each module and monitor the pressure of the fluid; the metering component is used to control the flow rate of the fluid.

[0048] The third aspect of the present invention provides the use of the catalyst-free non-ammonia denitrification system described in the first aspect in the denitrification of flue gas from an ethylene cracking furnace.

[0049] The system and method for catalyst-free non-ammonia denitrification provided by the present invention are described in detail below with reference to the accompanying drawings.

[0050] Figure 1 This is a system and process flow diagram for a catalyst-free, non-ammonia denitrification system according to a specific embodiment of the present invention. The system includes a reducing agent storage module, a distribution module, an injection module, and a reaction module, which are connected in sequence; wherein:

[0051] The reaction module includes an ethylene cracking furnace, and at least six injection ports are horizontally and equidistantly arranged on the side wall of the convection section of the furnace of the ethylene cracking furnace;

[0052] The injection module is used to atomize the non-ammonia bio-based denitrification reducing agent and inject it into the furnace of the ethylene cracking furnace; the injection module includes an injector group, and the injector group includes at least 6 dual-fluid spray guns, and the dual-fluid spray guns are arranged at the injection port;

[0053] The reducing agent storage module includes a reducing agent storage tank and a dosing pump connected in sequence;

[0054] A reflux pipeline is further provided between the reducing agent storage tank and the dosing pump;

[0055] The system further includes a dilution water module, which includes a water tank, a water pump, and a static mixer; the input end of the water pump is connected to the water tank, the output end of the water pump is connected to the input end of the static mixer; the output end of the static mixer is connected to the input end of the distribution module;

[0056] The output end of the reducing agent storage module is connected to the input end of the static mixer;

[0057] The injection module further comprises a gasification air device, and the input end of the injector group is connected to the output end of the distribution module and the gasification air device through pipelines respectively;

[0058] The system further comprises a monitoring component and a metering component, wherein the monitoring component comprises a plurality of valves and a plurality of pressure gauges, and the metering component comprises a plurality of flow meters.

[0059] The present invention will be described in detail below through examples.

[0060] In the present invention, 1 part by weight is 100 kg. In the following examples and comparative examples:

[0061] The ethylene cracking furnace is a 60,000 ton / year ethylene cracking furnace (exhaust gas volume 71000Nm 3 / h); the addition point is the convection section (the empty section above the lower mixing preheater);

[0062] The preparation method of the non-ammonia bio-based denitrification reducing agent used in Example 1 is as follows:

[0063] 4 parts by weight of biomass pyrolysis liquid (400 kg), 0.5 parts by weight of cyanuric acid, 0.5 parts by weight of deionized water, and 0.5 parts by weight of ethylene glycol were added to a reactor, stirred and mixed for 1 hour to obtain an emulsion, and then the emulsion was heated to 70° C. and kept at a constant temperature for 2 hours;

[0064] The preparation method of the non-ammonia bio-based denitrification reducing agent used in Example 2 is as follows:

[0065] 4 parts by weight of biomass pyrolysis liquid (400 kg), 0.9 parts by weight of cyanuric acid, 0.5 parts by weight of desalted water and 0.6 parts by weight of ethylene glycol were added to a reactor and stirred for 1.5 hours to obtain an emulsion, which was then heated to 75° C. and kept at a constant temperature for 2.5 hours.

[0066] Example 1

[0067] Use Figure 1 The system and method shown include a reductant storage module, a distribution module, an injection module, and a reaction module connected in sequence; wherein:

[0068] The reaction module includes an ethylene cracking furnace, and six injection ports are horizontally and equidistantly arranged on the side wall of the convection section of the furnace of the ethylene cracking furnace;

[0069] The injection module is used to atomize the non-ammonia bio-based denitrification reducing agent and inject it into the furnace of the ethylene cracking furnace; the injection module includes an injector group, which includes 6 dual-fluid spray guns, which are arranged at the above-mentioned injection ports, and each dual-fluid spray gun corresponds to each injection port one by one;

[0070] Each dual-fluid spray gun has six nozzle holes, each with a diameter of 1.6 mm. The spray angle is 70°, the horizontal spray distance is 3.2 m, and the spray flow rate is 19 L / h.

[0071] The reducing agent storage module includes a reducing agent storage tank and a dosing pump connected in sequence; a return line is also provided between the reducing agent storage tank and the dosing pump;

[0072] The system also includes a dilution water module, which includes a water tank, a water pump and a static mixer; the input end of the water pump is connected to the water tank, the output end of the water pump is connected to the input end of the static mixer; the output end of the static mixer is connected to the input end of the distribution module;

[0073] The output end of the reducing agent storage module is connected to the input end of the static mixer;

[0074] The injection module also includes a gasification air device, and the input end of the injector group is connected to the output end of the distribution module and the gasification air device through pipelines;

[0075] The above system also includes a monitoring component and a metering component, wherein the monitoring component includes multiple valves and multiple pressure gauges; the metering component includes multiple flow meters.

[0076] The method includes:

[0077] The non-ammonia bio-based denitrification reducing agent is atomized by the six dual-fluid spray guns and sprayed into the convection section of the furnace of the ethylene cracking furnace to contact with the flue gas of the ethylene cracking furnace to perform a reduction reaction; wherein:

[0078] The flow rate of the above non-ammonia bio-based denitrification reducing agent is 38L / h;

[0079] The non-ammonia bio-based denitrification reducing agent is provided in the form of an aqueous solution; the aqueous solution is obtained by mixing desalted water and the non-ammonia bio-based denitrification reducing agent, and the water-to-aqueous solution ratio (the volume flow ratio of desalted water to the non-ammonia bio-based denitrification reducing agent) is 2:1;

[0080] The conditions for the reduction reaction were: temperature 815 °C, time 0.28 s;

[0081] The flue gas temperature (temperature of the flue gas from the ethylene cracking furnace) is 815°C; in the flue gas from the ethylene cracking furnace, nitrogen oxides NO x The concentration is 82mg / m3 .

[0082] After the reduction reaction, NO x The concentration was reduced to 30 mg / m 3 Below (mean 23mg / m 3 ) and remain stable.

[0083] Example 2

[0084] The system and method according to Example 1 are different in that:

[0085] The flow rate of the non-ammonia bio-based denitrification reductant is 27L / h;

[0086] The non-ammonia bio-based denitrification reducing agent is provided in the form of an aqueous solution; the aqueous solution has a water-to-agent ratio of 2.5:1;

[0087] The conditions for the reduction reaction were: temperature 815 °C, time 0.28 s;

[0088] The nitrogen oxides NO in the flue gas of the ethylene cracking furnace x The concentration is 84 mg / m 3 ;

[0089] The rest are the same.

[0090] After the reduction reaction, NO x The concentration was reduced to 50 mg / m 3 Below (mean 46 mg / m 3 ) and remain stable.

[0091] Example 3

[0092] The system and method according to Example 1 are different in that:

[0093] The spray angle of each dual-fluid spray gun is 110°; the horizontal spray distance is 2m;

[0094] The rest are the same.

[0095] After the reduction reaction, NO x The concentration dropped to an average of 40 mg / m 3 And remain stable.

[0096] Comparative Example 1

[0097] The method of Example 1 is followed, except that:

[0098] The non-ammonia bio-based denitrification reductant was replaced with a 40 wt% urea solution; the volume flow ratio of deionized water to urea solution was 2:1;

[0099] The rest are the same.

[0100] After the reduction reaction, NO x The concentration dropped to an average of 73 mg / m 3 And remain stable.

[0101] From the above results, it can be seen that the system and method of Examples 1-2 of the present invention adopt a post-mixed dual-fluid spray gun with both penetrating power and atomizing effect, which is conducive to promoting the full mixing of the smoke agent under the condition of short residence time of the flue gas in the convection section, and the flue gas denitrification effect is better, meeting the requirements of ultra-clean emissions; Example 3 of the present invention adopts a different spray gun structure, and under the same dosage, the denitrification efficiency is reduced to a certain extent compared with Example 1. The denitrification agent used in Comparative Example 1 is 40wt% urea solution, and its denitrification effect is significantly reduced. Since the urea reducing agent is an amino SNCR, the NO x The reduction reaction of NOx is carried out in a specific reaction temperature range, which is relatively narrow, 850℃-1150℃. If the temperature is lower than 850℃, the NH3 reaction will be incomplete, forming the so-called "ammonia breakthrough", reducing NOx x The removal rate is low, so the denitrification efficiency of flue gas is extremely low.

[0102] In summary, the use of the system and method provided by the present invention to denitrify the flue gas of an ethylene cracking furnace can efficiently utilize the flue gas temperature and flue gas residence time in the furnace convection section of the ethylene cracking furnace, better exert the denitrification effect of the non-ammonia bio-based denitrification reducing agent injected into the convection section, and achieve ultra-clean flue gas emissions without changing the cracking furnace process flow and module settings.

[0103] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A catalyst-free, non-ammonia denitrification method, comprising: A non-ammonia bio-based denitrification reducing agent is atomized by at least six dual-fluid spray guns and injected into a convection section of a furnace of an ethylene cracking furnace to contact with flue gas of the ethylene cracking furnace to perform a reduction reaction; The non-ammonia bio-based denitrification reducing agent comprises: 4 parts by weight of biomass pyrolysis liquid, 0.5-1 parts by weight of cyanuric acid, 0.5-1 parts by weight of deionized water and 0.5-1 parts by weight of ethylene glycol; The reduction reaction conditions include: temperature of 600-1100° C. and time of 0.2-0.4 s.

2. The method according to claim 1, wherein The number of nozzle through holes of any of the two-fluid spray guns is 5-7, and the diameter of any of the through holes is 1-2 mm; Preferably, the spray angle of any of the two-fluid spray guns is 65-75°; the horizontal spray distance is 2.2-3.5 m; and the spray flow rate is not less than 15 L / h, preferably 15-30 L / h.

3. The method according to claim 1 or 2, wherein: The flow rate of the non-ammonia bio-based denitrification reducing agent is 20-40 L / h; Preferably, the non-ammonia bio-based denitrification reducing agent is provided in the form of an aqueous solution, wherein the aqueous solution is obtained by mixing desalted water with the non-ammonia bio-based denitrification reducing agent, and the water-to-agent ratio of the aqueous solution is 2-3:1; Preferably, the temperature of the reduction reaction is 650-900°C, preferably 700-850°C, more preferably 800-850°C.

4. The method according to any one of claims 1 to 3, wherein: The non-ammonia bio-based denitrification reducing agent is prepared by a method comprising the following steps: stirring and mixing 4 parts by weight of biomass pyrolysis liquid, 0.5-1 parts by weight of cyanuric acid, 0.5-1 parts by weight of deionized water, and 0.5-1 parts by weight of ethylene glycol for 1-2 hours to obtain an emulsion, and then heating the emulsion to a constant temperature of above 70° C. for 2-3 hours; Preferably, the concentration of nitrogen oxides in the flue gas of the ethylene cracking furnace is 80-90 mg / m 3 ; The concentration of SO2 is 0-5mg / m 3 ; Preferably, the temperature of the flue gas from the ethylene cracking furnace is 650-900°C, preferably 700-850°C, more preferably 800-850°C.

5. A catalyst-free non-ammonia denitrification system, characterized in that: The system includes a reductant storage module, a distribution module, an injection module and a reaction module connected in sequence; wherein: The reaction module includes an ethylene cracking furnace, and at least six injection ports are horizontally and equidistantly arranged on the side wall of the convection section of the furnace of the ethylene cracking furnace; The injection module is used to atomize the non-ammonia bio-based denitrification reducing agent and inject it into the furnace of the ethylene cracking furnace; the injection module includes an injector group, which includes at least 6 dual-fluid spray guns, and the dual-fluid spray guns are arranged at the injection port.

6. The system according to claim 5, wherein: The reducing agent storage module includes a reducing agent storage tank and a dosing pump connected in sequence; Preferably, a return line is further provided between the reducing agent storage tank and the dosing pump.

7. The system according to claim 5, wherein: The system also includes a dilution water module, which includes a water tank, a water pump and a static mixer; the input end of the water pump is connected to the water tank, the output end of the water pump is connected to the input end of the static mixer; the output end of the static mixer is connected to the input end of the distribution module.

8. The system according to claim 7, wherein: The output end of the reducing agent storage module is connected to the input end of the static mixer.

9. The system according to any one of claims 5 to 8, wherein: The injection module further comprises a gasification air device, and the input end of the injector group is connected to the output end of the distribution module and the gasification air device through pipelines respectively; Preferably, the system further comprises a monitoring component and a metering component, the monitoring component comprises a plurality of valves and a plurality of pressure gauges, and the metering component comprises a plurality of flow meters.

10. Use of the catalyst-free non-ammonia denitrification system according to any one of claims 5 to 9 in denitrification of flue gas from an ethylene cracking furnace.

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