Desulfurization and denitrification agent and use thereof

Abstract

The present invention relates to the field of flue gas purification and purification product recycling, and particularly provides a desulfurization and denitrification agent and a use thereof. In the present invention, by using an imidazoline amine oxide as a desulfurization and denitrification agent, NOx and SOx can be oxidized into HNO3 and H2SO4, and after the imidazoline amine oxide is reduced, the double-bond tertiary nitrogen can also be used as an alkali to neutralize H2SO4 and HNO3. In addition, in the present invention, the imidazoline amine oxide is used as a desulfurization and denitrification agent to carry out two-stage desulfurization and denitrification on flue gas, the waste liquid after the reaction is used as a foam acid liquid and injected into carbonate and tight sandstone reservoirs, the reservoir temperatures cause the waste liquid to slowly hydrolyze into H2SO4, HNO3, and HF, and the generated acid reacts with the reservoirs to implement production and injection stimulation of the reservoirs.

Description

A desulfurization and denitrification agent and its application Technical Field

[0001] The present invention relates to the field of flue gas purification and purification product recycling, and in particular to a desulfurization and denitrification agent and application thereof. Background Art

[0002] Flue gas contains NO x 、SO x To control air pollution, desulfurization and denitrification are necessary to remove polluting gases such as NO2. Desulfurization and denitrification methods include SCR, SNCR, SCO, alkaline absorption, and oxidation absorption. The alkaline absorption method is only applicable to NO2 and SO2, but not to NO. The oxidants and catalysts required by SCO and oxidation absorption methods are relatively expensive and easily poisoned by SO2, but they are very effective in removing NO. The reducing agents and desulfurization and denitrification products of SCR and SNCR methods can easily cause secondary pollution if not handled properly. In addition, the reaction temperatures are high and the catalyst costs are high. Therefore, the research and exploration of desulfurization and denitrification methods with a wide range of applications, low costs, and low secondary pollution risks has become an important research topic in this field. Chinese patent CN113137215A uses THEED or bipy as desulfurization and denitrification agents, and uses the flue gas desulfurization and denitrification products for carbonate reservoir acidification. This not only overcomes the secondary pollution disadvantages of traditional desulfurization and denitrification agents, but also allows for the inexpensive production of acidification solutions for carbonate reservoirs, thereby increasing reservoir production and injection. However, the desulfurization and denitrification products in this patent are hydrolyzed at high temperature in the column, thereby corroding the column and making it impossible to turn.

[0003] Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention proposes a desulfurization and denitrification agent and its application, which adopts imidazoline amine oxide to carry out secondary desulfurization and denitrification of flue gas, and uses the waste liquid and liquid nitrogen of desulfurization and denitrification for reservoir transformation, which can not only better control environmental pollution, but also can serve multiple purposes with one agent, reduce the cost of carbonate reservoir acidification, and realize slow acidification and shift acidification at the same time, solving the following problems of the existing technology: First, the existing desulfurization and denitrification process has a limited scope of application, high cost and energy consumption, and the desulfurization and denitrification products cannot be effectively utilized, which easily causes secondary pollution; second, in traditional acid fracturing, the acid-rock reaction rate is too fast, the action distance is short, and it is difficult to enter low permeability reservoirs, so the efficiency of clearing blockages is low; third, HF, HBF4 and the like in soil acid are dangerous to use and are more likely to form secondary precipitation; fourth, the desulfurization and denitrification products are hydrolyzed at high temperature in the pipe column, thereby corroding the pipe column, and the action distance is not long.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A desulfurization and denitrification agent is an imidazoline amine oxide; the imidazoline amine oxide contains two quaternary ammonium nitrogen atoms and a borofluoride group. Preferably, the imidazoline amine oxide is [MiO2][BF4]2 or [MsO2][BF4]2.

[0007] The waste liquid produced by the above desulfurization and denitrification agent is acidified to form a reservoir. The composition of the waste liquid can be combined with Ca 2+ Mg 2+ Chelation forms a polycyclic structure.

[0008] More preferably, [MsO2][BF4]2 is used as the desulfurization and denitrification agent. Since the waste liquid after desulfurization and denitrification by [MsO2][BF4]2 contains phenoxy groups, it can react with Al 3+ 、Fe 3+ Coordination increases the effect of dissolving sandstone.

[0009] The chemical formula of [MiO2][BF4]2 is:

[0010] The chemical formula of [MsO2][BF4]2 is:

[0011] The synthesis method of the desulfurization and denitrification agent comprises the following steps: using triethylenetetramine as a raw material, adding oxalic acid or salicylic acid dropwise to react to obtain a gemini imidazoline intermediate; subsequently adding 1-fluorooctane and boron trifluoride dropwise in sequence to react to obtain a quaternized gemini imidazoline; and finally using hydrogen peroxide as an oxidant to oxidize to obtain the desulfurization and denitrification agent.

[0012] Specifically, the synthesis method of [MiO2][BF4]2 is:

[0013] (1) Preparation of Gemini Imidazoline Intermediate: Triethylenetetramine was added to a reactor, heated to 100-120°C, and oxalic acid was added dropwise at a molar ratio of triethylenetetramine to oxalic acid of 1-1.4. The addition was completed within 0.5 hours. The reaction mixture was then heated to 150°C until no water was generated, and then heated to a reaction temperature of 240-260°C and the reaction was continued for 8 hours. After the reaction was completed, the by-products were removed by distillation under reduced pressure at 100°C for 5 hours to obtain the Gemini Imidazoline Intermediate.

[0014] The specific process is as follows:

[0015] (2) Preparation of [Mi][BF4]2: Place the gemini-imidazoline intermediate in a three-necked flask, use isopropanol as solvent, and heat in a constant-temperature water bath at 90°C; add 1-fluorooctane dropwise with stirring within 0.5 h; add boron trifluoride dropwise within 0.5 h; the molar ratio of the gemini-imidazoline intermediate, 1-fluorooctane, and boron trifluoride is 1:(0.9-1.1):(0.9-1.1); after the addition of boron trifluoride is completed, react for 1 h, then add 5 wt% NaOH solution dropwise to maintain the pH of the solution at 8-10; stir and react for 4 h, and evaporate under reduced pressure to obtain [Mi][BF4]2.

[0016] The specific process is as follows:

[0017] (3) Preparation of [MiO2][BF4]2: [Mi][BF4]2 was uniformly mixed with 10-30 wt% H2O2 solution and reacted for 1 h to obtain [MiO2][BF4]2.

[0018] The specific process is as follows:

[0019] Specifically, the synthesis method of [MsO2][BF4]2 is:

[0020] (1) Preparation of Gemini Imidazoline Intermediate: Triethylenetetramine was added to a reaction kettle, heated to 100-120°C, and salicylic acid was added dropwise at a molar ratio of 0.5-0.7 over 0.5 hours. The reaction was then heated to 150°C until no water was produced, and then heated to 240-260°C and the reaction was continued for 8 hours. After the reaction was completed, the by-products were removed by vacuum distillation at 100°C for 5 hours to obtain the Gemini Imidazoline Intermediate.

[0021] The specific process is as follows:

[0022] (2) Preparation of [Ms][BF4]2: Place the gemini imidazoline intermediate in a three-necked flask, use isopropanol as solvent, and heat in a constant-temperature water bath at 90°C; add 1-fluorooctane dropwise with stirring within 0.5 h; add boron trifluoride dropwise within 0.5 h; the molar ratio of imidazoline intermediate, 1-fluorooctane, and boron trifluoride is 1:(0.9-1.1):(0.9-1.1); after the addition of boron trifluoride is completed, react for 1 h, then add 5 wt% NaOH solution dropwise to maintain the pH of the solution at 8-10; stir and react for 4 h, and evaporate under reduced pressure to obtain quaternized gemini imidazoline [Ms][BF4]2.

[0023] The specific process is as follows:

[0024] LiOH was added to the quaternized geminiimidazoline at a molar ratio of 2-4. The mixture was stirred in 60 mL of tetrahydrofuran and 10 mL of water and heated to 70°C for 1 hour. Triethylene glycol dichloride was added at a molar ratio of 0.8-1.2, and the reaction was continued for 72 hours. After the reaction, the tetrahydrofuran was removed by rotary evaporation, and the residue was washed with water and extracted with chloroform. The tetrahydrofuran was then removed by rotary evaporation and crystallized from heptane to obtain [Ms][BF4]2.

[0025] The specific process is as follows:

[0026] (3) Preparation of [MsO2][BF4]2: [Ms][BF4]2 was mixed evenly with a 10-30% wt H2O2 solution and reacted for 1 hour to obtain [MsO2][BF4]2. The specific process is as follows:

[0027] The present invention also provides the application of the above-mentioned desulfurization and denitrification agent for flue gas desulfurization and denitrification and reuse of the purified products, including a flue gas desulfurization and denitrification process and a reservoir acidification process:

[0028] (1) Flue gas desulfurization and denitrification process:

[0029] The desulfurization and denitrification agents are sprayed into the flue gas in two stages in the opposite direction of the flue gas flow to obtain waste liquid; when the pH of the waste liquid reaches 6 to 6.5, the waste liquid generated by desulfurization and denitrification is collected;

[0030] Among them, the first stage is mainly for desulfurization, and the second stage is mainly for denitrification;

[0031] The waste liquid generated in the first stage is waste liquid 1, and the waste liquid generated in the second stage is waste liquid 2;

[0032] (2) Reservoir acidification process:

[0033] From far to near the oil well, inject slug 1, slug 2, slug 3, and slug 4 in sequence to increase production and injection;

[0034] Among them, slug 1 is liquid nitrogen, which is used to cool the wellbore and the area near the wellbore;

[0035] Segment 2 is waste liquid 2, which has less sulfate content and can prevent Ca 2+ Mg 2+ plasma precipitation;

[0036] Slug 3 is waste fluid 1, which is used to increase reservoir production and injection;

[0037] Segment 4 is liquid nitrogen, which is used for foaming and energizing the acid solution.

[0038] The present invention adds a liquid nitrogen slug after the waste liquid slug to generate foam in the waste liquid and realizes diversion through the Jamin effect; adds a liquid nitrogen slug before the waste liquid to cool the wellbore and the near-well area to prevent the desulfurization and denitrification products from hydrolyzing and corroding the pipe column.

[0039] Specifically, the flue gas desulfurization and denitrification process is carried out in two stages. In the first stage, the desulfurization and denitrification agents are preferentially reacted with SO x The desulfurization rate is higher than the denitrification rate. The flue gas entering the second stage contains more NO, so the second stage is mainly for denitrification. In each stage, the desulfurization and denitrification agent solution in process (1) or process (2) is sprayed into the flue gas in the opposite direction of the flue gas flow. An air heat exchange pipe is provided in each stage. At the same time, the air flows through the second stage and the first stage air heat exchange pipe in turn and finally enters the furnace. Because the desulfurization and denitrification reaction is an exothermic reaction, the reaction heat is absorbed by the air, which is conducive to the right shift of the desulfurization and denitrification reaction and achieves the effect of preheating the air. When the pH of the waste liquid reaches 6-6.5, the waste liquid generated by desulfurization and denitrification is collected. The waste liquids generated in the first stage and the second stage are waste liquid 1 and waste liquid 2, respectively, as shown in Figure 1. The desulfurization and denitrification agent converts NO x 、SO x Oxidized to H2SO4, HNO3, and reduced to [Mi][BF4]2 or [Ms][BF4]2, which acts as an alkali to neutralize H2SO4 and HNO3. The resulting waste liquid contains 0.010% to 0.025% of [H2Mi] 4+ or [H2Ms] 4+ Preferably, the desulfurization and denitrification agent is a 0.020wt% [MiO2][BF4]2 aqueous solution or a 0.020wt% [MsO2][BF4]2 aqueous solution.

[0040] Preferably, the pH of the desulfurization and denitrification waste liquid is 6.5.

[0041] The operation steps of the reservoir acidizing process are shown in FIG2 , specifically:

[0042] Before acidizing, liquid nitrogen is injected into the target layer as a slug 1 to cool the wellbore and the area near the wellbore. The amount is 0.1 to 0.3 m3 per meter of oil layer. 3 , preferably 0.2m per meter of oil layer 3 ;

[0043] Use waste liquid 2 as pre-slug 2, 10 to 50 m per meter of oil layer 3 , preferably 15m per meter of oil layer 3 The sulfate content in this section is low, which can prevent Ca 2+ Mg 2+ plasma precipitation;

[0044] Then the waste liquid 1 is injected as the slug 3, 20 to 100 m per meter of oil layer. 3 , preferably 80m per meter of oil layer 3 ;

[0045] Finally, liquid nitrogen is injected again as slug 4, 1 to 1.5 m per meter of oil layer 3 , preferably 1.2m per meter of oil layer 3 .

[0046] The injection flow rate of each plug is 100-250 L / min, and preferably, the injection flow rate of each plug is 200 L / min.

[0047] Among them, the waste liquid 1 mainly contains 0.010% to 0.025% of [H2Mi] 4+ or [H2Ms] 4+ The mixed salt of nitric acid and fluoroboric acid, the waste liquid 2 contains 0.010% to 0.025% of [H2Mi] 4+ or [H2Ms] 4+ The reservoir temperature causes the nitrate and sulfate in the waste liquid to slowly hydrolyze to produce H2SO4 and HNO3, and the fluoroborate to hydrolyze to produce HF, which can slowly acidify the sandstone; at the same time [Mi] 2+ or [Ms] 2+ With Ca 2+ Mg 2+ 、Fe 3+ It has equal coordination and plays the role of corrosion inhibition and iron ion stabilization in pipelines.

[0048] Working principle:

[0049] The present invention adopts imidazoline amine oxides [MiO2][BF4]2 and [MsO2][BF4]2 for secondary desulfurization and denitrification of flue gas, replacing traditional oxidants, alkalis and catalysts. The desulfurization and denitrification agent is the oxidation product of gemini imidazoline quaternary ammonium salt [Mi][BF4]2 or [Ms][BF4]2. [Mi][BF4]2 and [Ms][BF4]2 have two double-bonded tertiary nitrogens, which are easy to react with H + , Ca 2+ Mg 2+ 、Fe 3+ The present invention uses amine oxide desulfurization and denitrification agent to achieve multiple uses, that is, NO x 、SO x Oxidized to HNO3, H2SO4, and reduced to [Mi][BF4]2, [Ms][BF4]2, where the double bond tertiary nitrogen acts as a base to neutralize H2SO4, HNO3. 4+ or [H2Ms] 4+A mixed salt of nitric acid, sulfuric acid, and fluoroboric acid is used as the acid to acidify the reservoir; adding liquid nitrogen slugs before and after the waste liquid slug can reduce the temperature of the wellbore and near-wellbore area, prevent excessive hydrolysis of the mixed salt and corrosion of the tubing, and make it safer to use; at the same time, liquid nitrogen energizes and foams the waste liquid, which is effective in increasing production and injection in low-permeability channels. The reservoir temperature causes the nitrates and sulfates in the waste liquid to slowly hydrolyze to produce HNO3 and H2SO4, and the fluoroborates to hydrolyze to produce HF, which can slow the acidification of sandstone; at the same time, [Mi] 2+ or [Ms] 2+ With Ca 2+ Mg 2+ 、Fe 3+ The coordination is equal, achieving the effect of corrosion inhibition and stabilization of iron ions in the pipeline, and promoting the hydrolysis of nitrates and sulfates in the reservoir.

[0050] One or more technical solutions provided by the embodiments of the present invention have at least the following technical effects:

[0051] (1) The present invention is the first to use imidazoline amine oxide as a desulfurization and denitrification agent for flue gas desulfurization and denitrification, which can not only control air and water pollution, but also save flue gas treatment energy consumption and cost, and improve the desulfurization and denitrification rate.

[0052] (2) The present invention uses the waste liquid produced by desulfurization and denitrification as acid to transform the reservoir, and uses liquid nitrogen to cool the wellbore and the area near the wellbore to suppress [H2Mi] 4+ or [H2Ms] 4+ The hydrolysis of [Mi][BF4]2 has basically no corrosive effect on the pipeline. [Mi][BF4]2 or [Ms][BF4]2 can be better adsorbed on the pipe wall and have a longer action distance, achieving the effect of corrosion inhibition and deceleration. At the same time, [Mi][BF4]2 or [Ms][BF4]2 contains a longer fatty chain, and the waste liquid produced by desulfurization and denitrification is used as a foaming agent, and liquid nitrogen causes it to produce foam, so the reservoir homogeneity is better after the transformation.

[0053] (3) The present invention adopts [BF4] - Replacing HF dissolved sandstone can not only achieve the effect of slowing down, but also increase the safety of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is a flow chart of desulfurization and denitrification;

[0055] Figure 2 is a schematic diagram of a slug for increased production and injection;

[0056] Figure 3 shows the changes in injection pressure and injection volume of the C-2 injection well in Application Example 2 from 2019 to 2023. DETAILED DESCRIPTION

[0057] The present invention will be further described below with reference to specific embodiments, but is not limited thereto.

[0058] It should be noted that the experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents, materials and equipment described are all commercially available unless otherwise specified.

[0059] The preparation method of [MiO2][BF4]2 is:

[0060] Triethylenetetramine was added to a reactor, heated to 110°C, and oxalic acid was added dropwise at a molar ratio of 1.2. The addition was completed over 0.5 hours. The reaction was then heated to 150°C and continued until no water was produced. The reaction was then heated to 260°C and continued for 8 hours. After the reaction was completed, byproducts were removed by vacuum distillation at 100°C for 5 hours to obtain a gemini imidazoline intermediate. The gemini-imidazoline intermediate was placed in a three-necked flask, heated in a constant-temperature water bath at 90°C using isopropanol as the solvent, and 1-fluorooctane was added dropwise with stirring over 0.5 h. Boron trifluoride was also added dropwise over 0.5 h. The molar ratio of the gemini-imidazoline intermediate, 1-fluorooctane, and boron trifluoride was 1:1.1:1.05. After the boron trifluoride addition was complete, the reaction was allowed to proceed for 1 h. A 5 wt% NaOH solution was then added dropwise to maintain the pH of the solution at 9. The reaction was stirred for 4 h, and vacuum distillation was performed to obtain [Mi][BF4]2. [Mi][BF4]2 was then mixed with a 20 wt% H2O2 solution and allowed to react for 1 h to obtain [MiO2][BF4]2, where the molar ratio of [Mi][BF4]2 to H2O2 was 1:3.

[0061] The synthesis method of [MsO2][BF4]2 is:

[0062] Triethylenetetramine was added to a reactor and heated to 115°C. Salicylic acid was then added dropwise at a molar ratio of 0.6. The addition was completed over 0.5 hours. The reaction was then heated to 150°C and continued until no water was produced. The reaction was then heated to 255°C and continued for 8 hours. After the reaction was completed, byproducts were removed by vacuum distillation at 100°C for 5 hours to obtain the gemini imidazoline intermediate. The gemini imidazoline intermediate is placed in a three-necked flask, isopropanol is used as a solvent, and the solution is heated in a constant temperature water bath at 90°C; 1-fluorooctane is added dropwise with stirring, and the addition is completed within 0.5 h; boron trifluoride is added dropwise, and the addition is completed within 0.5 h; the molar ratio of the gemini imidazoline intermediate, 1-fluorooctane, and boron trifluoride is 1:1.1:1.05; after the addition of boron trifluoride is completed, the solution is reacted for 1 h, and then 5 wt% NaOH solution is added dropwise to maintain the pH of the solution at 10; the reaction is stirred for 4 h, and vacuum distillation is performed to obtain a quaternized gemini imidazoline.

[0063] LiOH was added to the quaternized geminiimidazoline at a molar ratio of 3:1. The mixture was stirred in 60 mL of tetrahydrofuran and 10 mL of water and heated to 70°C for 1 hour. Triethylene glycol dichloride was added at a molar ratio of 1:1 and the reaction was continued for 72 hours. After the reaction, the tetrahydrofuran was rotary evaporated, the residue washed with water, and then extracted with chloroform. The tetrahydrofuran was rotary evaporated and crystallized from heptane to obtain [Ms][BF4]2. [Ms][BF4]2 was mixed with a 20 wt% H2O2 solution and allowed to react for 1 hour to obtain [MsO2][BF4]2, where the molar ratio of [Mi][BF4]2 to H2O2 was 1:3.

[0064] Example 1

[0065] A desulfurization and denitrification agent is used for flue gas desulfurization and denitrification and recycling of the purified products, comprising the following steps:

[0066] (1) Flue gas desulfurization and denitrification process: Desulfurization and denitrification are carried out in two stages. In each stage, a 0.020 wt% [MiO2][BF4]2 aqueous solution is sprayed into the flue gas in the opposite direction of the flue gas flow. An air heat exchange tube is provided in each stage. At the same time, the air flows through the second-stage and first-stage air heat exchange tubes in sequence and finally enters the furnace. When the pH of the system reaches 6.5, the waste liquid generated by desulfurization and denitrification is collected. The waste liquids generated in the first and second stages are waste liquid 1 and waste liquid 2, respectively. The waste liquids are acid liquids.

[0067] (2) Reservoir acidification process: Before acidification, liquid nitrogen is injected into the target layer as a slug 1, with 0.2m per meter of oil layer. 3 Wastewater 2 is used as pre-slug 2, and 15m3 is injected into each meter of oil layer. 3 Then the waste liquid 1 is injected as the slug 3, 80m per meter of oil layer 3 Finally, liquid nitrogen was injected again as segment 4, with 1.2m per meter of oil layer. 3 The injection flow rate of each plug is 200L / min. Among them, the waste liquid 1 mainly contains 0.020% of [H2Mi] 4+ or [H2Ms] 4+ The mixed salt of nitric acid and fluoroboric acid, waste liquid 2 contains 0.020% [H2Mi] 4+ or [H2Ms] 4+ A mixed salt of nitric acid, sulfuric acid and fluoroboric acid.

[0068] The dissolution rate and corrosion rate of the acid solution were tested according to SY / T5358-2002 "Reservoir Sensitivity Flow Test Method". The operating steps for testing the dissolution rate and corrosion rate of cuttings in different acid systems are as follows:

[0069] 5 g of rock cuttings were placed in test tubes containing 500 mL of acid solution, and then the test tubes were placed in a 90°C water bath for full reaction for 120 minutes and filtered to obtain the rock cutting dissolution rate. Using the coupon weight loss method, the coupons were derusted, degreased, dried, weighed, and immersed in the acid solution. After 120 minutes, the coupons were removed, washed to remove residual acid, dried, weighed, and the corrosion rate was obtained. The results are shown in Table 1.

[0070] Example 2

[0071] A desulfurization and denitrification agent is used for flue gas desulfurization and denitrification and recycling of the purified products, comprising the following steps:

[0072] (1) Flue gas desulfurization and denitrification process: Desulfurization and denitrification are carried out in two stages. In each stage, 0.020wt% [MsO2][BF4]2 solution is sprayed into the flue gas in the opposite direction of the flue gas flow. An air heat exchange pipe is provided in each stage. At the same time, the air flows through the second-stage and first-stage air heat exchange pipes in sequence and finally enters the furnace. When the pH of the system reaches 6.5, the waste liquid generated by desulfurization and denitrification is collected. The waste liquids generated by the first and second stages are waste liquid 1 and waste liquid 2, respectively. The waste liquids are acid liquids.

[0073] (2) Reservoir acidification process: Before acidification, liquid nitrogen is injected into the target layer as a slug 1, with 0.2m per meter of oil layer. 3 Wastewater 2 is used as pre-slug 2, and 15m3 is injected into each meter of oil layer. 3 Then the waste liquid 1 is injected as the slug 3, 80m per meter of oil layer 3 Finally, liquid nitrogen was injected again as segment 4, with 1.2m per meter of oil layer. 3 The injection flow rate of each plug was 200 L / min. The dissolution rate and corrosion rate of the acid solution were tested according to the method in Example 1. The results are shown in Table 1.

[0074] Comparative Example 1

[0075] (1) Flue gas desulfurization and denitrification process: 0.015% of THEED by mass is added to a 15% of H2O2 solution by mass to prepare a mixed solution, wherein the volume ratio of THEED to H2O2 is 75:1. The mixed solution is sprayed into the flue gas in the opposite direction of the flue gas flow. When the pH of the system reaches 6.5, the waste liquid generated by desulfurization and denitrification is collected, and the waste liquid is the acid solution.

[0076] (2) The obtained acid solution can be directly injected into the formation to increase production and injection. The acid solution contains about 0.015% [H2THEED] 2+ The dissolution rate and corrosion rate of the acid solution were tested according to the method in Example 1. The results are shown in Table 1.

[0077] Comparative Example 2

[0078] (1) Flue gas desulfurization and denitrification process: 0.015% by mass of Bipy is added to a 15% by mass of H2O2 solution to prepare a mixed solution, wherein the volume ratio of Bipy to H2O2 is 400:3. The mixed solution is sprayed into the flue gas in the opposite direction of the flue gas flow. When the pH of the system reaches 6.5, the waste liquid generated by desulfurization and denitrification is collected, and the waste liquid is the acid solution.

[0079] (2) The obtained acid solution can be directly injected into the formation to increase production and injection. The acid solution contains about 0.015% [H2bipy] 2+ The dissolution rate and corrosion rate of the acid solution were tested according to the method in Example 1. The results are shown in Table 1.

[0080] Comparative Example 3

[0081] (1) Flue gas desulfurization and denitrification process: Desulfurization and denitrification are carried out in two stages. In each stage, 0.015% of THEED by mass is added to a 15% H2O2 solution by mass to prepare a mixed solution. The volume ratio of THEED to H2O2 is 75:1. The mixed solution is sprayed into the flue gas in the opposite direction of the flue gas flow. An air heat exchange pipe is provided in each stage. At the same time, the air flows through the second-stage and first-stage air heat exchange pipes in sequence and finally enters the furnace. When the pH of the system reaches 6.5, the waste liquid generated by desulfurization and denitrification is collected. The waste liquids generated in the first stage and the second stage are waste liquid 1 and waste liquid 2, respectively. The waste liquid is acid liquid.

[0082] (2) Reservoir acidification process: Before acidification, liquid nitrogen is injected into the target layer as a slug 1, with 0.2m per meter of oil layer. 3 Wastewater 2 is used as pre-slug 2, and 15m3 is injected into each meter of oil layer. 3 Then the waste liquid 1 is injected as the slug 3, 80m per meter of oil layer 3 Finally, liquid nitrogen was injected again as segment 4, with 1.2m per meter of oil layer. 3 The injection flow rate of each plug was 200 L / min. The dissolution rate and corrosion rate of the acid solution were tested according to the method in Example 1. The results are shown in Table 1.

[0083] It can be seen from Comparative Examples 1 and 2 that in Example 1, [MiO2][BF4]2 is used to replace the desulfurization and denitrification agent in patent CN113137215A, and the dissolution rate is increased by 0.616 times compared with Comparative Example 1 and nearly 1.176 times compared with Comparative Example 2; the corrosion rate is 91% of that in Comparative Example 1 and 98% of that in Comparative Example 2; in Example 2, [MsO2][BF4]2 is used to replace the desulfurization and denitrification agent in patent CN113137215A, and the dissolution rate is increased by 0.864 times compared with that in Comparative Example 1 and nearly 1.511 times compared with that in Comparative Example 2; the corrosion rate is 86% of that in Comparative Example 1 and 93% of that in Comparative Example 2.

[0084] In addition, it can be seen from Comparative Example 3 that THEED does not contain borofluoride and will not hydrolyze to produce HF that can dissolve sandstone when heated. Therefore, even if liquid nitrogen is used to cool the wellbore and the area near the wellbore, the effect of inhibiting hydrolysis is not obvious, and THEED is difficult to react with Ca 2+ Mg 2+ 、Fe 3+ 、Al 3+ The formation of stable complexes, the corrosion inhibition and retardation effects are not as good as [H2Ms] 4+ 、[H2Mi] 4+ Obviously. Also [H2Ms] 4+ 、[H2Mi] 4+ Containing hydrophobic functional groups, it can foam when exposed to liquid nitrogen, achieving a diversion effect, so the corrosion inhibition and deceleration effects are more obvious; and when THEED is used as a desulfurization and denitrification agent, the generated product [H2THEED] 2+ It contains no fatty chains and does not foam when exposed to liquid nitrogen. It cannot block large pores through the Jamin effect, and the acidified formation still exhibits strong heterogeneity. Therefore, the dissolution rates of Comparative Example 3 are 70% and 60% of those of Examples 1 and 2, respectively; the corrosion rates are 0.034 times and 0.091 times higher than those of Examples 1 and 2, respectively. The dissolution rate of Comparative Example 3 is 0.127 times higher than that of Comparative Example 1, and the corrosion rate is 94% of that of Comparative Example 1, demonstrating that liquid nitrogen, by cooling the wellbore, inhibits the hydrolysis of desulfurization and denitrification products into sulfuric acid and nitric acid, thereby achieving corrosion and velocity reduction effects.

[0085] The acid solution of the present invention can dissolve more sandstone, and its production increase and injection increase and corrosion inhibition performance are better than the desulfurization and denitrification agent in patent CN113137215A; in addition, [H2Ms] 4+ Acidized reservoir, due to [H2Ms] 4+ Contains phenoxy, than [H2Mi] 4+ Easy with Fe 3+ 、Al 3+ Coordinate and adsorb on the surface of the pipeline, better dissolve the aluminosilicate minerals, and show better production increase, injection increase and corrosion inhibition performance.

[0086] Table 1 Dissolution rate and corrosion rate of cuttings in different acid systems

[0087] Application Example 1

[0088] In 2022, 0.020wt% [MiO2][BF4]2 aqueous solution was successfully applied to the flue gas desulfurization and denitrification of the T oil field P thermal power plant. Previously, the power plant used the desulfurization and denitrification agent in Comparative Example 2. Now, 0.020wt% [MiO2][BF4]2 aqueous solution is sprayed into the flue gas, and the NO content of the flue gas before and after passing through the curing agent is measured by gas chromatography. x 、SO xThe desulfurization and denitrification efficiency was obtained by the concentration, as shown in Table 2, and the mass fractions of sulfate and nitrate in the desulfurization and denitrification wastewater were measured by liquid chromatography. It can be seen that the desulfurization and denitrification efficiency of [MiO2][BF4]2 is higher than that of bipy, and the eutrophication of the water body has been controlled; in the first stage, the desulfurization and denitrification agent preferentially reacts with SO x The desulfurization efficiency of the reaction is higher than that of the second stage. The flue gas entering the second stage contains more NO, and the denitrification efficiency of the second stage is higher than that of the first stage.

[0089] Table 2 Desulfurization and denitrification efficiency of curing agents prepared with different H2O2 and bipy volume ratios

[0090] Application Example 2

[0091] In February 2019, the solution in Comparative Example 1 was used to acidify and increase the injection volume of the C-2 water injection well in the S oil field, with an injection flow rate of 5m 3 / h, the water injection pressure after construction is 18MPa, and the daily water injection volume is 124m 3 / d, water injection pressure before construction in June 2022 was 18MPa, and daily water injection volume was 124m 3 / d, the waste liquid generated in the desulfurization and denitrification process of Example 2 was acidified and injected, the acid injection flow rate was 200L / min, the injection pressure after construction was 15MPa, and the daily water injection volume was 224m 3 / d, as shown in Figure 3, is still valid.

Claims

1. A desulfurization and denitrification agent, characterized in that: The desulfurization and denitrification agent is an imidazoline amine oxide; The imidazoline amine oxide contains two quaternary ammonium nitrogen atoms; The imidazoline amine oxide further contains a borofluoride group.

2. The desulfurization and denitrification agent according to claim 1, characterized in that: The imidazoline amine oxide is [MiO2][BF4]2 or [MsO2][BF4]2; The chemical formula of [MiO2][BF4]2 is: The chemical formula of [MsO2][BF4]2 is:

3. The desulfurization and denitrification agent according to claim 2, characterized in that: The synthesis method of the desulfurization and denitrification agent comprises the following steps: using triethylenetetramine as a raw material, adding oxalic acid or salicylic acid to react to obtain a gemini imidazoline intermediate; then successively adding 1-fluorooctane and boron trifluoride to react to obtain a quaternized gemini imidazoline; and finally using hydrogen peroxide as an oxidant to oxidize to obtain the desulfurization and denitrification agent.

4. An application of the desulfurization and denitrification agent according to any one of claims 1 to 3, characterized in that: Used for flue gas desulfurization and denitrification and reuse of purified products, including flue gas desulfurization and denitrification processes and reservoir acidification processes: (1) Flue gas desulfurization and denitrification process: The desulfurization and denitrification agents are sprayed into the flue gas in the opposite direction of the flue gas flow in two stages to obtain waste liquid; when the pH of the waste liquid reaches 6 to 6.5, the waste liquid generated by desulfurization and denitrification is collected; The waste liquid produced in the first stage is waste liquid 1, and the waste liquid produced in the second stage is waste liquid 2; (2) Reservoir acidification process: Segment 1, segment 2, segment 3 and segment 4 are injected in sequence from far to near the oil well to increase production and injection; among them, segment 1 is liquid nitrogen, segment 2 is waste liquid 2, segment 3 is waste liquid 1, and segment 4 is liquid nitrogen.

5. The use according to claim 4, characterized in that: The desulfurization and denitrification agent is a [MiO2][BF4]2 aqueous solution with a mass fraction of 0.010% to 0.025% or a [MsO2][BF4]2 aqueous solution with a mass fraction of 0.010% to 0.025%.

6. The use according to claim 4, characterized in that: In the slug 1, the amount of liquid nitrogen injected is 0.1-0.3 m3 per meter of oil layer. 3 ; In the slug 2, the injection amount of the waste liquid 2 is 10 to 50 m3 per meter of oil layer. 3 ; In the slug 3, the injection amount of the waste liquid 1 is 20 to 100 m3 per meter of oil layer. 3 ; The amount of liquid nitrogen injected into the segment plug 4 is 1 to 1.5 m3 per meter of oil layer. 3 .

7. The use according to claim 4, characterized in that: The waste liquid 1 mainly contains 0.010% to 0.025% of [H2Mi] 4+ A mixed salt of nitric acid and fluoroboric acid or 0.010% to 0.025% [H2Ms] 4+ A mixed salt of nitric acid and fluoroboric acid; The waste liquid 2 contains 0.010% to 0.025% [H2Mi] by mass 4+ A mixed salt of nitric acid, sulfuric acid, fluoroboric acid or 0.010% to 0.025% [[H2Ms] 4+ A mixed salt of nitric acid, sulfuric acid and fluoroboric acid.

8. The use according to claim 4, characterized in that: The injection flow rate of each plug is 100-250L / min.

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