A method and system for treating nitrophenol waste solid

Abstract

The first aspect of the present invention provides a method for treating nitrophenol waste solids, comprising the following steps: S1, adding sodium hydroxide solution into a preparation kettle, stirring and heating; S2, adding nitrophenol waste solids into the preparation kettle of step S1, stirring, and preparing sodium nitrophenolate solution; S3, using a centrifugal pump and a spray gun to spray the sodium nitrophenolate solution prepared in step S2 into a regenerative thermal incinerator. The second aspect of the present invention provides a system for treating nitrophenol waste solids, comprising a preparation kettle and a regenerative thermal incinerator, wherein a centrifugal pump is arranged between the preparation kettle and the regenerative thermal incinerator, the centrifugal pump is connected to the preparation kettle through a first connecting pipe, the centrifugal pump is connected to the regenerative thermal incinerator through a second connecting pipe, and a spray gun is installed at the end away from the second connecting pipe. The method for treating nitrophenol waste solids and the supporting treatment system provided by the present invention are more economical, more environmentally friendly and safer than the existing process, and can convert nitrophenol waste solids into sodium nitrophenolate wastewater for safe incineration treatment.

Description

Technical Field

[0001] The invention belongs to the field of chemical waste pharmaceutical treatment, and specifically relates to a treatment method and a treatment system for nitrophenol waste solid. Background Art

[0002] During the alkaline washing process of mixed dinitrobenzene, nitrophenol substances are produced by the reaction to generate sodium nitrophenol organic salts that are dissolved in water. The current treatment method is to acidify the alkaline wastewater with dilute sulfuric acid to a pH value of 1-2, and then cool it to 5-10°C. Finally, the nitrophenol waste solids and the wastewater containing a small amount of nitrophenol are separated by suction filtration, filter press or centrifugal separation. The separated waste solids are sent to a waste solid incineration site for open-air incineration. The separated wastewater is neutralized, iron-carbon micro-electrolysis, catalytic oxidation, filtered, and finally biochemically treated and deep electro-Fenton treated to meet the discharge standards.

[0003] The above method has the following shortcomings: First, the water content of the waste solid must be ensured. If the water content of the waste solid is lower than 10-15%, the storage, transportation, loading and unloading of the waste solid will have safety hazards. If the water content of the waste solid is greater than 20-25%, it is not easy to ignite during incineration, and the combustion process is slow, the combustion is incomplete, and there are many residues; Second, open-air combustion will produce a large amount of thick smoke mixed with carbides to pollute the atmosphere due to insufficient oxygen supply and incomplete combustion during the combustion process; Third, the waste solid residue after combustion is still hazardous waste and difficult to handle; Fourth, the heat generated by combustion cannot be fully utilized. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method and system for treating nitrophenol waste solids, which is more economical, environmentally friendly and safer than the existing process.

[0005] The first aspect of the present invention provides a method for treating nitrophenol waste solids, comprising the following steps:

[0006] S1, add sodium hydroxide solution into the preparation kettle, stir and heat up;

[0007] S2, adding the nitrophenol waste solid into the preparation kettle of step S1, stirring, and preparing a sodium nitrophenolate solution;

[0008] S3, using a centrifugal pump and a spray gun to spray the sodium nitrophenolate solution prepared in step S2 into the regenerative heat incinerator.

[0009] Further, in step S1, the concentration of the sodium hydroxide solution is 10%, and the temperature is raised to 80° C.-90° C. The concentration of the sodium hydroxide solution is set to 10% for the purpose of facilitating batching and preventing precipitation of sodium hydroxide at high concentrations, and the water is heated to 80° C.-90° C. to increase the solubility of sodium nitrophenolate in water, ensure that sodium nitrophenolate is dissolved in water without precipitation, and facilitate the transportation of the sodium nitrophenolate solution.

[0010] Furthermore, in steps S1 and S2, in parts by weight, nitrophenol waste solid: sodium hydroxide: water = 1: (0.32-0.36): (2.75-3.50). The purpose of a large proportion of sodium hydroxide is to ensure that all nitrophenols react to generate sodium nitrophenolate and dissolve in water.

[0011] Furthermore, in step S2, it also includes: after the sodium nitrophenolate solution is prepared, a sodium hydroxide solution with a concentration of 10% is used to adjust the pH value of the sodium nitrophenolate solution to 8-10. An appropriate excess of sodium hydroxide is used to adjust the solution to alkalinity, so as to ensure that the nitrophenolic substances are completely converted into sodium nitrophenolate salts, and to ensure that the inorganic acid in the nitrophenolic waste solids is converted into inorganic salts. Adjusting the solution to alkalinity can also prevent the acid in the waste medicine from corroding the transportation pipeline and equipment.

[0012] Furthermore, in step S3, the outlet flow rate of the spray gun is 1-2.5 m / s. 3 / h, the outlet pressure of the spray gun is 0.2-0.4MPa, and the temperature of the regenerative thermal incinerator is 900℃-1000℃. The purpose of setting up the spray gun is to atomize the sodium nitrophenolate solution in the regenerative thermal incinerator to achieve the purpose of maximizing incineration.

[0013] Furthermore, in step S3, it also includes using a blower to input oxygen into the regenerative incinerator. The purpose of inputting oxygen is to make the atomized sodium nitrophenolate burn more fully.

[0014] Furthermore, the high-temperature flue gas generated by the regenerative incinerator in step S3 enters the waste heat boiler to generate steam for heating the configuration kettle in step S1, or the excess steam is incorporated into the steam network to provide heat for other places in need. This greatly saves resources and reduces processing costs.

[0015] Furthermore, the method also includes step S4. In step S4, the low-temperature flue gas after incineration in step S3 is discharged in compliance with the emission standards after dust removal, denitrification, desulfurization and other processes. The solid waste residue after incineration can be partially reused for the preparation of sodium nitrophenolate aqueous solution after cooling, crushing and packaging, and the excess can be used for the alkali preparation post of the wastewater treatment plant.

[0016] The second aspect of the present invention provides a nitrophenol waste solid treatment system for use in the above-mentioned nitrophenol waste solid treatment method, comprising a preparation kettle and a regenerative thermal incinerator, a centrifugal pump is provided between the preparation kettle and the regenerative thermal incinerator, the centrifugal pump is connected to the preparation kettle via a first connecting pipe, the centrifugal pump is connected to the regenerative thermal incinerator via a second connecting pipe, a spray gun is installed at the end of the second connecting pipe away from the centrifugal pump, and the spray gun is arranged inside the regenerative thermal incinerator.

[0017] Furthermore, it also includes a water high-level tank, a liquid alkali high-level tank, a waste heat boiler, a dust collector, a denitrification tower and a desulfurization tower. The water high-level tank and the liquid alkali high-level tank are respectively connected to the configuration kettle, the waste heat boiler is connected to the thermal storage incinerator, the dust collector is connected to the waste heat boiler, the denitrification tower is connected to the dust collector, and the desulfurization tower is connected to the denitrification tower.

[0018] Furthermore, a steam pipe is provided between the waste heat boiler and the configuration kettle, for conveying the steam generated by the waste heat boiler to the configuration kettle to heat the material in the configuration kettle.

[0019] Furthermore, the spray gun forms an acute angle of 10°-30° with the inner wall of the regenerative thermal incinerator, so that the sodium nitrophenolate solution is in a turbulent state in the inner space of the regenerative thermal incinerator, thereby enhancing its combustion efficiency.

[0020] The beneficial effects of the present invention are:

[0021] The treatment method of nitrophenol waste solids provided by the present invention and its supporting treatment system are more economical, more environmentally friendly and safer than the existing process, and can convert nitrophenol waste solids into sodium nitrophenol wastewater for safe incineration treatment. It does not produce a large amount of carbonized flue gas discharged after incineration in the prior art, does not produce incompletely incinerated waste solids, and does not cause secondary pollution to the environment. The calorific value of the sodium nitrophenolate aqueous solution configured by the present invention is about 5000 to 6000 kcal / kg. The heat energy generated by incineration can be used by a waste heat boiler to generate steam for use by auxiliary devices, and can also be incorporated into the company's steam pipeline network for use by other production lines. The solid waste residue generated by the present invention mainly contains 75% sodium carbonate and 25% sodium hydroxide, which can be used for the configuration of the present invention and the alkali preparation post of the wastewater treatment plant, so that the input raw materials are maximized. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The figure is a schematic diagram of the structure of the nitrophenol waste solid treatment system of the present invention.

[0023] Figure numerals: 1-preparation kettle, 11-agitator, 2-regenerative incinerator, 3-centrifugal pump, 31-first connecting pipe, 32-second connecting pipe, 321-spray gun, 4-water high-level tank, 5-liquid alkali high-level tank, 6-waste heat boiler, 61-steam pipe, 7-dust collector, 8-denitrification tower, 9-desulfurization tower. DETAILED DESCRIPTION

[0024] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. If no specific conditions are specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer shall be followed.

[0025] Example 1

[0026] This embodiment provides a method for treating nitrophenol waste solids, comprising the following steps:

[0027] S1, add sodium hydroxide solution into the preparation kettle, stir and heat up;

[0028] Specifically, the concentration of the added sodium hydroxide solution was 10%, and the temperature was raised to 85° C. and maintained there.

[0029] S2, adding the nitrophenol waste solid into the preparation kettle of step S1, stirring, and preparing a sodium nitrophenolate solution;

[0030] Specifically, in step S1 and step S2, in parts by weight, nitrophenol waste solid: sodium hydroxide: water = 1:0.34:3.25, and then a 10% sodium hydroxide solution is used to adjust the pH value of the sodium nitrophenolate solution to 9. The alkaline solution is conducive to ensuring that the nitrophenol substances are completely converted into nitrophenol sodium salts, and that the inorganic acid in the nitrophenol waste solid is converted into inorganic salts. Adjusting the solution to alkalinity can also prevent the acid in the waste medicine from corroding the transportation pipeline and equipment.

[0031] S3, using a centrifugal pump and a spray gun to spray the sodium nitrophenolate solution prepared in step S2 into a regenerative incinerator;

[0032] Specifically, the outlet flow rate of the spray gun is 2.0m 3 / h, the outlet pressure of the spray gun is 0.3MPa, and the temperature of the regenerative incinerator is 1000℃. The purpose of setting the spray gun is to atomize the sodium nitrophenolate solution in the regenerative incinerator to achieve the purpose of maximizing incineration. In step S3, it also includes using a blower to input oxygen into the regenerative incinerator. The purpose of inputting oxygen is to make the atomized sodium nitrophenolate incinerated more fully; in addition, the high-temperature flue gas generated by the regenerative incinerator enters the waste heat boiler to generate steam for heating the configuration kettle in step S1, or the excess steam is incorporated into the steam network to provide heat for other places in need. This greatly saves resources and reduces processing costs.

[0033] S4. The low-temperature flue gas after incineration in step S3 is discharged after dust removal, denitrification, desulfurization and other processes. The solid waste residue after incineration can be partially reused for the preparation of sodium nitrophenolate aqueous solution after cooling, crushing and packaging, and the excess can be used for alkali preparation in the wastewater treatment plant.

[0034] Example 2

[0035] The remaining features are the same as those of Example 1, except that, in step S1 and step S2, in parts by weight, nitrophenol waste solid: sodium hydroxide: water = 1:0.32:2.75.

[0036] Example 3

[0037] The remaining features are the same as those of Example 1, except that, in step S1 and step S2, in parts by weight, nitrophenol waste solid: sodium hydroxide: water = 1:0.36:3.50.

[0038] Example 4

[0039] The remaining features are the same as those of Example 1, except that, in step S2, a 10% sodium hydroxide solution is used to adjust the pH value of the sodium nitrophenolate solution to 8.

[0040] Example 5

[0041] The remaining features are the same as those of Example 1, except that, in step S2, a 10% sodium hydroxide solution is used to adjust the pH value of the sodium nitrophenolate solution to 10.

[0042] Example 6

[0043] The remaining features are the same as those of Example 1, except that in step S3, the outlet flow rate of the spray gun is 1 m / s. 3 / h, the outlet pressure of the spray gun is 0.2MPa.

[0044] Example 7

[0045] The remaining features are the same as those of Example 1, except that in step S3, the outlet flow rate of the spray gun is 2.5 m / s. 3 / h, the outlet pressure of the spray gun is 0.4MPa.

[0046] Example 8

[0047] The remaining features are the same as those of Example 1, except that in step S3, the temperature of the regenerative thermal incinerator is 900°C.

[0048] Example 10

[0049] The remaining features are the same as those of Example 1, except that in step S1, the temperature is raised to 80°C and maintained there.

[0050] Embodiment 11

[0051] The remaining features are the same as those of Example 1, except that in step S1, the temperature is increased to 90°C and maintained there.

[0052] This embodiment also provides a processing system supporting the above-mentioned nitrophenol waste solid processing method.

[0053] A nitrophenol waste solid treatment system for use in the above-mentioned nitrophenol waste solid treatment method, comprising a preparation kettle 1 and a regenerative thermal incinerator 2, wherein the preparation kettle 1 is provided with an agitator 11, the top of the preparation kettle 1 is provided with a feed port, the bottom of the regenerative thermal incinerator 2 is provided with a slag removal port, a centrifugal pump 3 is provided between the preparation kettle 1 and the regenerative thermal incinerator 2, the centrifugal pump 3 is connected to the preparation kettle 1 through a first connecting pipe 31, and the centrifugal pump 3 is connected to the regenerative thermal incinerator 2 through a second connecting pipe 32. The furnace 2 is connected to the configuration kettle 1 for pumping the sodium nitrophenolate solution in the configuration kettle 1 into the regenerative thermal incinerator 2. A spray gun 321 is installed at the end of the second connecting pipe 32 away from the centrifugal pump 3. The spray gun 321 is arranged inside the regenerative thermal incinerator 2. The spray gun 321 forms an acute angle of 10°-30° with the inner wall of the regenerative thermal incinerator 2 along the circumferential direction of the regenerative thermal incinerator 2, so that the sodium nitrophenolate solution is in a turbulent state in the internal space of the regenerative thermal incinerator 2, thereby enhancing its combustion efficiency.

[0054] The treatment system also includes a water high-level tank 4, a liquid alkali high-level tank 5, a waste heat boiler 6, a dust collector 7, a denitrification tower 8 and a desulfurization tower 9. The water high-level tank 4 and the liquid alkali high-level tank 5 are respectively connected to the configuration kettle 1 through metal pipes, the waste heat boiler 6 is connected to the thermal storage incinerator 2 through metal pipes, the dust collector 7 is connected to the waste heat boiler 6 through metal pipes, the denitrification tower 8 is connected to the dust collector 7 through metal pipes, and the desulfurization tower 8 is connected to the denitrification tower 9 through metal pipes. A steam through pipe 61 is provided between the waste heat boiler 6 and the configuration kettle 1, which is used to transport the steam generated by the waste heat boiler 6 to the configuration kettle 1 to heat the material in the configuration kettle 1.

[0055] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for treating nitrophenol waste solids, It is characterized in that The steps include: S1, add sodium hydroxide solution into the preparation kettle, stir and heat up; S2, adding the nitrophenol waste solid to the preparation kettle of step S1, stirring, and obtaining a sodium nitrophenolate solution by weight ratio of nitrophenol waste solid: sodium hydroxide: water = 1: (0.32-0.36): (2.75-3.50), and then adjusting the pH value of the sodium nitrophenolate solution to 8-10 with a sodium hydroxide solution having a mass concentration of 10%; S3, using a centrifugal pump and a spray gun to spray the sodium nitrophenolate solution prepared in step S2 into the regenerative incinerator, the outlet flow rate of the spray gun is 1-2.5m 3 / h, the outlet pressure of the spray gun is 0.2-0.4MPa, the temperature of the regenerative thermal incinerator is 900℃-1000℃, and the spray gun forms an acute angle of 10°-30° with the inner wall of the regenerative thermal incinerator.

2. The method for treating nitrophenol waste solid according to claim 1, It is characterized in that In step S1, the concentration of the sodium hydroxide solution is 10%, and the temperature is increased in the range of 80°C-90°C.

3. The method for treating nitrophenol waste solid according to claim 1, It is characterized in that In step S3, the method further includes using a blower to input oxygen into the regenerative thermal incinerator.

4. The method for treating nitrophenol waste solid according to claim 1, It is characterized in that The high-temperature flue gas generated by the regenerative incinerator in step S3 enters the waste heat boiler to generate steam for heating the preparation kettle in step S1.

5. A system for treating nitrophenol waste solids, for use in the method for treating nitrophenol waste solids according to any one of claims 1 to 4, It is characterized in that It includes a preparation kettle and a regenerative thermal incinerator, a centrifugal pump is arranged between the preparation kettle and the regenerative thermal incinerator, the centrifugal pump is connected to the preparation kettle through a first connecting pipe, the centrifugal pump is connected to the regenerative thermal incinerator through a second connecting pipe, a spray gun is installed at the end of the second connecting pipe away from the centrifugal pump, and the spray gun is arranged inside the regenerative thermal incinerator.

6. The system for treating nitrophenol waste solid according to claim 5, It is characterized in that It also includes a water high-level tank, a liquid alkali high-level tank, a waste heat boiler, a dust collector, a denitrification tower and a desulfurization tower. The water high-level tank and the liquid alkali high-level tank are connected to the preparation kettle respectively, the waste heat boiler is connected to the thermal storage incinerator, the dust collector is connected to the waste heat boiler, the denitrification tower is connected to the dust collector, and the desulfurization tower is connected to the denitrification tower.

7. The system for treating nitrophenol waste solid according to claim 6, It is characterized in that A steam passage is provided between the waste heat boiler and the preparation kettle.

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