Device and method for removing SO2 from flue gas by recycling fly ash from garbage combustion

Abstract

The present invention belongs to the technical field of waste incineration fly ash treatment, specifically relating to a device and method for recycling waste incineration fly ash to remove SO2 from flue gas. The device comprises a waste incineration flue gas purification system and a fly ash treatment system; the waste incineration flue gas purification system comprises a desulfurization tower, a dust collector, and a chimney connected in sequence; the fly ash treatment system comprises a fly ash collection device, a water washing device, a drying device, an ultrasonic device, an isopropyl alcohol solution storage tank, and a centrifugal device; the fly ash collection device is connected to the dust collector; and the desulfurization tower is connected to the centrifugal device. The present invention produces fly ash with a high specific surface area, capable of effectively removing sulfur and acid, thereby achieving fly ash reuse at a low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste incineration fly ash treatment, and in particular relates to a device and method for removing SO2 from flue gas by recycling waste incineration fly ash. Background Art

[0002] Flue gas desulfurization (FGD) is the removal of sulfur from flue gas, primarily used to prevent and control air pollution. Sulfur dioxide in flue gas from municipal solid waste incineration has become a major cause of air pollution, posing serious risks to both humans and the ecological environment. Therefore, controlling SO2 in flue gas is crucial to improving air pollution. Desulfurization by injecting adsorbents into flue gas is a relatively mature flue gas purification method. Currently, Ca(OH)2 is the primary adsorbent used in industry. While it offers high adsorption efficiency, it comes at a high cost.

[0003] The waste incineration process will produce a large amount of fly ash, which is about 2-5% of the mass of the waste entering the furnace. The main components of waste incineration fly ash are CaO, CaSO4, CaOH2, SiO2, Al2O3, MgO, heavy metals Pb, Cd, Fe, Cr, Cu, Zn and dioxins. Because it contains dioxins and heavy metals, it is treated as hazardous solid waste both at home and abroad and cannot enter the ecological environment without special treatment. With the promotion and application of incineration treatment in urban domestic waste, the output of waste incineration fly ash is increasing, although the bulk density of waste incineration fly ash is only 600kg / m 3 However, stockpiling and landfilling take up a lot of space, so the task of timely disposal of incineration fly ash is very urgent. Summary of the Invention

[0004] The purpose of the present invention is to provide a device and method for recycling garbage combustion fly ash to remove SO2 in flue gas, which can obtain fly ash with high specific surface area and can effectively remove sulfur and acid, thereby realizing the recycling of fly ash at low cost.

[0005] Specifically, the present invention first provides a device for removing SO2 from flue gas by reusing fly ash from garbage combustion, including a garbage incineration flue gas purification system and a fly ash treatment system;

[0006] The waste incineration flue gas purification system includes a desulfurization tower, a dust collector and a chimney connected in sequence;

[0007] The fly ash treatment system includes a fly ash collection device, a water washing device, a drying device, an ultrasonic device, an isopropyl alcohol solution storage tank and a centrifugal device;

[0008] in:

[0009] The fly ash collecting device is connected to the dust collector and is used to collect fly ash generated in the dust collector;

[0010] The water washing device is connected to the fly ash collecting device and is used to wash the fly ash collected in the fly ash collecting device with water;

[0011] The drying device is connected to the water washing device and is used to dry the washed fly ash produced by the water washing device;

[0012] The ultrasonic device is connected to the drying device and is used to add the dried fly ash produced by the drying device into the isopropyl alcohol solution for ultrasonic dispersion;

[0013] The isopropyl alcohol solution storage tank is connected to the ultrasonic device and is used to replenish the isopropyl alcohol solution into the ultrasonic device;

[0014] The centrifugal device is connected to the ultrasonic device and is used to centrifuge the ultrasonically dispersed fly ash and isopropyl alcohol solution mixture generated by the ultrasonic device;

[0015] The desulfurization tower is connected to the centrifugal device, and the fly ash produced by the centrifugal device is precipitated into the desulfurization tower to desulfurize the flue gas.

[0016] The present invention finds that by first adding the washed fly ash into a solution for ultrasonic dispersion and then treating it with a high-speed centrifuge, fly ash with high specific surface area can be obtained, which can effectively desulfurize and deacidify, thereby realizing efficient reuse of the fly ash.

[0017] At the same time, compared with the use of traditional aqueous solutions or other alcohol solutions for ultrasonic treatment, the use of isopropyl alcohol solution in the present invention can significantly increase the specific surface area of ​​fly ash.

[0018] Preferably, the dust collector is a bag dust collector.

[0019] Preferably, the drying device is a heating evaporation drying device.

[0020] The present invention also provides a method for removing SO2 from flue gas by recycling fly ash from garbage combustion using the above device, comprising the following steps:

[0021] A. The fly ash from garbage combustion is removed by desulfurization tower and dust collector in turn before being discharged through the chimney; the fly ash collected by the dust collector is sent to the fly ash collection device;

[0022] B. The fly ash in the fly ash collection device is sent to the water washing device for water washing;

[0023] C sends the washed fly ash to the drying device for drying;

[0024] D. feeding the dried fly ash into an ultrasonic device and performing ultrasonic dispersion in an isopropyl alcohol solution;

[0025] E. feeding the ultrasonically dispersed fly ash and isopropyl alcohol solution mixture into a centrifugal device for centrifugation;

[0026] F The fly ash sediment after centrifugation is injected into the desulfurization tower to desulfurize the flue gas.

[0027] Preferably, in step B, the water washing temperature is 80-100°C.

[0028] Preferably, in step C, the drying is heating evaporation drying.

[0029] Preferably, in step D, the isopropanol solution is an aqueous solution of isopropanol, and the concentration of the isopropanol solution is 5-15 v / v%.

[0030] Preferably, in step D, the ultrasonic dispersion time is 30-60 minutes, and the ultrasonic dispersion frequency is 10-30 kHz. Ultrasonic dispersion treatment helps the solution to fully contact the fly ash, achieving a better digestion effect.

[0031] Preferably, in step D, the mass ratio of the isopropyl alcohol solution to the fly ash is 4-6:1.

[0032] Preferably, in step E, the centrifugal speed is 500-1000 rpm.

[0033] Preferably, in step F, the fly ash after centrifugation is precipitated and dried, and then injected into the desulfurization tower.

[0034] The beneficial effects of the present invention are:

[0035] The device and method for recycling garbage combustion fly ash to remove SO2 in flue gas provided by the present invention can obtain fly ash with high specific surface area, can effectively remove sulfur and acid, thereby realizing the recycling of fly ash at low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the description of the prior art in the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a process flow chart for removing SO2 from flue gas by recycling fly ash from garbage combustion in Example 1.

[0038] Figure 2 The BET results of the fly ash treated with the isopropyl alcohol solution in Example 1 are compared with those of the original fly ash. DETAILED DESCRIPTION

[0039] The following examples are intended to illustrate the present invention but are not intended to limit the scope of the present invention. Modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and substance of the present invention are intended to fall within the scope of the present invention.

[0040] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in this field or the product instructions were used. All reagents or instruments without manufacturer specified are conventional products that can be purchased through regular channels.

[0041] Example 1

[0042] Partial reference Figure 1 , a device for removing SO2 from flue gas by reusing fly ash from garbage combustion, comprising a garbage incineration flue gas purification system and a fly ash treatment system;

[0043] The waste incineration flue gas purification system includes a desulfurization tower, a bag dust collector and a chimney connected in sequence;

[0044] The fly ash treatment system includes a fly ash collection device, a water washing device, a heating evaporation drying device, an ultrasonic device, an isopropyl alcohol solution storage tank and a centrifugal device;

[0045] in:

[0046] The fly ash collecting device is connected to the bag dust collector and is used to collect fly ash generated in the bag dust collector;

[0047] The water washing device is connected to the fly ash collecting device and is used to wash the fly ash collected in the fly ash collecting device with water;

[0048] The heating evaporation drying device is connected to the water washing device and is used to dry the washed fly ash produced by the water washing device;

[0049] The ultrasonic device is connected to the heating evaporation drying device and is used to add the dried fly ash produced by the heating evaporation drying device into the isopropyl alcohol solution for ultrasonic dispersion;

[0050] The isopropyl alcohol solution storage tank is connected to the ultrasonic device and is used to replenish the isopropyl alcohol solution into the ultrasonic device;

[0051] The centrifugal device is connected to the ultrasonic device and is used to centrifuge the ultrasonically dispersed fly ash and isopropyl alcohol solution mixture generated by the ultrasonic device;

[0052] The desulfurization tower is connected to the centrifugal device, and the fly ash produced by the centrifugal device is precipitated into the desulfurization tower to desulfurize the flue gas.

[0053] A method for removing SO2 from flue gas by recycling fly ash from garbage combustion using the above device comprises the following steps:

[0054] A. The fly ash from garbage combustion is removed by desulfurization tower and dusted by bag filter before being discharged through the chimney; the fly ash collected by the bag filter is sent to the fly ash collection device;

[0055] The fly ash in the fly ash collection device B is sent to the water washing device for 90℃ water washing;

[0056] C. Sending the washed fly ash to a heating evaporation drying device for heating and evaporation drying in a boiling water bath;

[0057] D. The dried fly ash is fed into an ultrasonic device and ultrasonically dispersed in a 10% isopropyl alcohol solution (the mass ratio of the isopropyl alcohol solution to the fly ash is 5:1). The ultrasonic dispersion time is 50 minutes and the ultrasonic dispersion frequency is 20 kHz.

[0058] E. The fly ash and isopropyl alcohol solution mixture after ultrasonic dispersion is fed into a centrifugal device for centrifugation at a speed of 1000 rpm for 30 minutes;

[0059] F After centrifugal ash precipitation and drying, it is injected into the desulfurization tower to desulfurize the flue gas.

[0060] Figure 2 The BET results of the fly ash treated with isopropyl alcohol solution in Example 1 are compared with those of the original fly ash. It can be seen that after the isopropyl alcohol treatment, the specific surface area of ​​the fly ash increases from 14.9 m 2 / s increased to 20.1m 2 / s, which can effectively remove sulfur and acid and realize the efficient reuse of fly ash.

[0061] The above embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineers and technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A device for removing SO2 from flue gas by recycling fly ash from garbage combustion, characterized in that: Including waste incineration flue gas purification system and fly ash treatment system; The waste incineration flue gas purification system includes a desulfurization tower, a dust collector and a chimney connected in sequence; The fly ash treatment system includes a fly ash collection device, a water washing device, a drying device, an ultrasonic device, an isopropyl alcohol solution storage tank and a centrifugal device; in: The fly ash collecting device is connected to the dust collector and is used to collect fly ash generated in the dust collector; The water washing device is connected to the fly ash collecting device and is used to wash the fly ash collected in the fly ash collecting device with water; The drying device is connected to the water washing device and is used to dry the washed fly ash produced by the water washing device; The ultrasonic device is connected to the drying device and is used to add the dried fly ash produced by the drying device into the isopropyl alcohol solution for ultrasonic dispersion; The isopropyl alcohol solution storage tank is connected to the ultrasonic device and is used to replenish the isopropyl alcohol solution into the ultrasonic device; The centrifugal device is connected to the ultrasonic device and is used to centrifuge the ultrasonically dispersed fly ash and isopropyl alcohol solution mixture generated by the ultrasonic device; The desulfurization tower is connected to the centrifugal device, and the fly ash produced by the centrifugal device is precipitated into the desulfurization tower to desulfurize the flue gas.

2. The device according to claim 1, characterized in that The dust collector is a bag dust collector.

3. The device according to claim 1 or 2, characterized in that The drying device is a heating evaporation drying device.

4. A method for removing SO2 from flue gas by recycling fly ash from garbage combustion using the device according to any one of claims 1 to 3, characterized in that: The following steps are involved: A. The fly ash from garbage combustion is removed from the sulfur tower and dusted by the dust collector before being discharged through the chimney. The fly ash collected by the dust collector is sent to the fly ash collection device. B. The fly ash in the fly ash collection device is sent to the water washing device for water washing; C. Send the washed fly ash to the drying device for drying; D. feeding the dried fly ash into an ultrasonic device and performing ultrasonic dispersion in an isopropyl alcohol solution; E. sending the ultrasonically dispersed fly ash and isopropyl alcohol solution mixture into a centrifugal device for centrifugation; F. The fly ash precipitate after centrifugation is injected into the desulfurization tower to desulfurize the flue gas.

5. The method according to claim 4, characterized in that In step B, the water washing temperature is 80-100°C.

6. The method according to claim 4 or 5, characterized in that In step C, the drying is performed by heating and evaporation.

7. The method according to claim 4 or 5, characterized in that In step D, the isopropanol solution is an aqueous solution of isopropanol, and the concentration of the isopropanol solution is 5-15 v / v%.

8. The method according to claim 4 or 5, characterized in that In step D, the ultrasonic dispersion time is 30-60 min, and the ultrasonic dispersion frequency is 10-30 KHz.

9. The method according to claim 4 or 5, characterized in that In step D, the mass ratio of the isopropyl alcohol solution to the fly ash is 4-6:

1.

10. The method according to claim 4 or 5, characterized in that In step E, the centrifugal speed is 500-1000 rpm.

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