Method for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals

Abstract

The present invention belongs to the technical field of solid waste treatment and sulfur resource utilization, and relates to a method for adjusting the atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals. The sludge is made into sludge powder, and the sludge powder is treated with sulfur-containing flue gas at a set temperature to eliminate O2 in the sulfur-containing flue gas and generate CO and / or H2 to obtain a tempering gas. Under the action of a double-effect catalyst, the tempering gas uses the CO and / or H2 generated in the tempering gas to reduce sulfur oxides and nitrogen oxides in the tempering gas to obtain nitrogen and sulfur element. At the same time, the sulfur element reacts with the heavy metals in the tempering gas to produce sulfides, and the tempering gas after the reaction is separated into gas and solid. The present invention can not only realize the coordinated disposal of sludge and avoid excessive emissions of CO, but also can realize the removal of multiple pollutants (SO2, NO X , CO and volatile heavy metals).

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste treatment and sulfur resource utilization, and relates to a method for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Restore SO 2 Sulfur preparation is a good sulfur recovery process, which can not only solve SO 2 Emissions and pollution problems can also alleviate the current shortage of sulfur resources. CO reduces SO 2 The technology is considered to be a desulfurization process with great industrial prospects due to its wide sources, few side reactions and high product purity. 2 , which can easily cause catalyst poisoning and failure, and requires pretreatment; the flue gas contains SO 2 In addition to other pollutants, such as NOx, heavy metals, etc., the overall flue gas purification process is cumbersome, and the heavy metals are only transferred but not solidified and recycled.

[0004] Sludge contains heavy metals, various bacteria and viruses, etc. Improper disposal can cause serious disease transmission and secondary environmental pollution. In existing sludge disposal technologies, problems such as pollutant control, cost reduction and product value-added have not been well solved. The safety and stability of heavy metals are the focus of attention. It is urgent to develop more advanced and environmentally friendly sludge treatment methods and processes. Summary of the invention

[0005] In order to solve the shortcomings of the prior art, the purpose of the present invention is to provide a method for adjusting the atmosphere of sulfur-containing flue gasification sludge to reduce sulfur and nitrate and solidify heavy metals, which can not only achieve the coordinated treatment of sludge and avoid excessive emissions of CO, but also achieve multiple pollutants (SO 2 、NO X , CO and volatile heavy metals).

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] On the one hand, a method for adjusting the atmosphere by gasifying sludge with sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals, wherein the sludge is made into sludge powder, and the sludge powder is treated with sulfur-containing flue gas at a set temperature to reduce the O in the sulfur-containing flue gas. 2 Eliminate the simultaneous generation of CO and / or H 2etc., to achieve sludge disposal and reaction atmosphere regulation, obtain conditioned gas, and the conditioned gas is used to generate CO and / or H in the conditioned gas under the action of a dual-effect catalyst. 2 The sulfur oxides and nitrogen oxides in the tempering gas are reduced to obtain nitrogen and sulfur, thereby achieving desulfurization and denitrification. At the same time, sulfur vapor reacts with heavy metals in the tempering gas to produce sulfides, thereby fixing the heavy metals. The tempering gas after the reaction is separated into gas and solid.

[0008] The present invention uses the generated CO as a reducing agent to perform dual-effect catalytic desulfurization and denitrification. At the same time, it uses the characteristics of sulfur and heavy metals such as Hg, Cd, and Pb to easily react to form stable low-toxic sulfides, which can achieve the removal of volatile heavy metals while enriching and mineralizing heavy metals, and can be separated and recovered through "sulfurization-volatilization". However, the residual O 2 Catalytic reduction of SO to CO 2 and NO have an important influence, which is the key to restricting the reduction efficiency. Therefore, the present invention uses sulfur-containing flue gas to treat the sludge first, and then eliminates O in the sulfur-containing flue gas. 2 CO and / or H are produced simultaneously 2 Etc., to achieve sludge disposal and reaction atmosphere control.

[0009] In addition, compared with further oxidation of sulfur oxides to produce sulfuric acid, the sulfur prepared in the present invention has the advantages of higher added value, wide application, and easy storage and transportation.

[0010] On the other hand, a system for adjusting the atmosphere of sulfur-containing flue gasification sludge to reduce sulfur and nitrate and solidify heavy metals comprises:

[0011] A sludge pretreatment module, used to convert sludge into sludge powder;

[0012] Flue gasification sludge conditioning module is used to treat sludge powder with sulfur-containing flue gas and eliminate O in the sulfur-containing flue gas. 2 CO and / or H are generated simultaneously 2 ;

[0013] The dual-effect reduction and synergistic solidification heavy metal module receives the conditioned gas from the flue gasification sludge conditioning module and is used to catalyze the CO and / or H in the conditioned gas. 2 The sulfur oxides and nitrogen oxides in the conditioning gas are subjected to a reduction reaction to obtain nitrogen and sulfur element, and at the same time, the sulfur element reacts with the heavy metals in the conditioning gas to produce sulfides.

[0014] In a third aspect, an application of the above method or system in treating urban solid waste or carbon-containing industrial solid waste is provided, wherein the urban solid waste or carbon-containing industrial solid waste replaces the sludge in the method or system.

[0015] The beneficial effects of the present invention are:

[0016] The present invention realizes the conditioning of flue gas components (deoxidation + providing reducing agent) by gasifying sulfur-containing flue gas sludge, creates a favorable reaction atmosphere for catalytic reduction, constructs a dual-effect catalyst to realize the dual-effect catalytic reduction of sulfur and nitrate, and the product sulfur cooperates with the solidification of heavy metals released by sludge gasification, which can effectively prevent the discharge of heavy metals, thereby realizing the multi-pollutant (SO 2 、NO X , CO and volatile heavy metals), optimize the resource utilization of metallurgical sulfur-containing flue gas or the coordinated disposal of sludge in cement kilns, innovate and improve the existing technical approaches for high-value utilization of metallurgical sulfur-containing flue gas and industrial by-product gypsum, and have important research significance and application prospects for waste treatment or coordinated disposal to achieve resource utilization of solid waste.

[0017] The method of the present invention is suitable for comprehensive utilization of bulk solid waste, heavy metal treatment and reduction of SO 2 It can not only alleviate the shortage of sulfur resources in my country and realize resource-based desulfurization, but also reasonably dispose of urban solid waste such as sludge, so that the volatile heavy metals analyzed can be processed and secondary pollution can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0019] Figure 1 This is a schematic diagram of the structure of a system for adjusting the atmosphere of sulfur-containing flue gasification sludge to reduce sulfur and nitrate and solidify heavy metals in Example 1 of the present invention;

[0020] Figure 2 It is a structural schematic diagram of a gasifier according to Example 1 of the present invention;

[0021] Among them, 1. sludge pretreatment module, 2. flue gas gasification sludge conditioning module, 3. rotary kiln module, 4. dual-effect reduction and synergistic solidification heavy metal module, 5. sulfur condensation and separation module, 6. tail gas treatment module, 7. sludge powder, 8. mesh support structure, 9. gas inlet, 10. solid import and export, 11. gas outlet. DETAILED DESCRIPTION

[0022] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] In view of the fact that the existing cement kilns co-dispose of sludge, which leads to unfavorable cement production and excessive CO emissions, the present invention proposes a method for adjusting the atmosphere by gasifying sludge with sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals.

[0025] A typical embodiment of the present invention provides a method for adjusting the atmosphere by gasifying sludge with sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals, wherein the sludge is made into sludge powder, and the sludge powder is treated with sulfur-containing flue gas at a set temperature to reduce the sulfur in the sulfur-containing flue gas. 2 Eliminate the simultaneous generation of CO and / or H 2 The conditioned gas is obtained, and the conditioned gas is reacted with the CO and / or H generated in the conditioned gas under the action of a dual-effect catalyst. 2 The sulfur oxides and nitrogen oxides in the conditioning gas are subjected to a reduction reaction to obtain nitrogen and sulfur element. At the same time, the sulfur element reacts with the heavy metals in the conditioning gas to produce sulfides.

[0026] The present invention realizes the conditioning of flue gas components (deoxidation + providing reducing agent) by gasifying carbon-containing materials such as sludge from sulfur-containing flue gas, creates a favorable reaction atmosphere for catalytic reduction, constructs a dual-effect catalyst to realize the dual-effect catalytic reduction of sulfur and nitrate, and the product sulfur synergistically solidifies the heavy metals released during the gasification process, thereby achieving the multi-pollutant (SO 2 、NO X , CO and volatile heavy metals).

[0027] The sulfur-containing flue gas described in the present invention may be coal-fired flue gas or metallurgical flue gas. In cement production, industrial by-product gypsum acts as a calcium source to replace limestone raw materials, thereby reducing CO 2 However, since gypsum contains a large amount of sulfur, its calcined flue gas contains a large amount of SO 2 At this time, the sulfur-containing flue gas can also be the calcination flue gas generated by the cement rotary kiln.

[0028] The contact area between powdered sludge and flue gas is larger, which promotes oxygen consumption and is conducive to the analysis of organic pollutants such as volatile heavy metals. In some embodiments, the sludge is dried, crushed, and sieved to obtain sludge powder. The particle size of the sludge powder is preferably 40-80 mesh.

[0029] In some embodiments, during the treatment of sludge powder by sulfur-containing flue gas, the temperature is 600°C to 1200°C, preferably 600°C to 850°C.

[0030] In some embodiments, the sludge residue after the sludge powder is treated with sulfur-containing flue gas is used as a raw material for cement production.

[0031] In some embodiments, the sulfur-containing flue gas is used to treat the sludge powder in the gasifier. The residence time of the sulfur-containing flue gas in the gasifier is 0.5 to 3 seconds. Within this residence time range, the O 2 Carry out effective processing.

[0032] In some embodiments, the temperature of the reduction reaction is 500-600 °C.

[0033] In some embodiments, the dual-action catalyst is a pyrite / iron sulfide-based catalyst.

[0034] In some embodiments, CO / H 2 with SO 2 The molar ratio of / NOx is 2:0.9~1.1.

[0035] In some embodiments, the conditioned gas is subjected to gas-solid separation after the reaction, and the separated gas is used to gasify the sludge powder.

[0036] Another embodiment of the present invention provides a system for adjusting the atmosphere of sulfur-containing flue gasification sludge to reduce sulfur and nitrate and solidify heavy metals, comprising:

[0037] A sludge pretreatment module, used to convert sludge into sludge powder;

[0038] Flue gasification sludge conditioning module is used to treat sludge powder with sulfur-containing flue gas and eliminate O in the sulfur-containing flue gas. 2 Simultaneous generation of CO and / or H 2 ;

[0039] The dual-effect reduction and synergistic solidification heavy metal module receives the conditioned gas from the flue gasification sludge conditioning module and is used to catalyze the CO and / or H in the conditioned gas. 2 The sulfur oxides and nitrogen oxides in the conditioning gas are subjected to a reduction reaction to obtain nitrogen and sulfur element, and at the same time, the sulfur element reacts with the heavy metals in the conditioning gas to produce sulfides.

[0040] In some embodiments, the flue gasification sludge conditioning module is a gasifier. More specifically, the gasifier includes a shell and a support structure, the support structure is arranged on the cross section of the shell, the support structure is a mesh support structure, and the shell is provided with a gas inlet, a gas outlet and a solid inlet, and the support structure is located between the gas inlet and the gas outlet. The mesh support structure can not only play a certain supporting role for the catalyst, but also allow the gas to pass through, so that the gas and the reaction solid can fully contact and react.

[0041] In some embodiments, the dual-effect reduction and synergistic solidification heavy metal module is a reduction tower. More specifically, the structure of the reduction tower is consistent with the structure of the above-mentioned gasifier, that is, it includes a shell and a support structure, the support structure is arranged on the cross section of the shell, the support structure is a mesh support structure, and the shell is provided with a gas inlet, a gas outlet and a solid inlet, and the support structure is located between the gas inlet and the gas outlet.

[0042] In some embodiments, a rotary kiln module is included, and part of the raw materials of the rotary kiln module are sludge residues produced by the flue gasification sludge conditioning module.

[0043] In some embodiments, a tail gas treatment module is included for absorbing harmful gases.

[0044] In one or more embodiments, the gas outlet of the tail gas treatment module is connected to the gas inlet of the flue gas gasification sludge conditioning module.

[0045] A third embodiment of the present invention provides an application of the above method or system in treating urban solid waste or carbon-containing industrial solid waste, where the urban solid waste or carbon-containing industrial solid waste replaces the sludge in the method or system.

[0046] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0047] Example

[0048] The system of sulfur-containing flue gasification sludge regulating atmosphere to reduce sulfur and nitrate and solidify heavy metals, such as Figure 1 As shown, it includes a sludge pretreatment module 1, a flue gasification sludge conditioning module 2, a dual-effect reduction synergistic solidification heavy metal module 4, a sulfur condensation separation module 5 and a tail gas treatment module 6 connected in sequence. The solid phase outlet of the flue gasification sludge conditioning module 2 is connected to the rotary kiln module 3. The flue gasification sludge conditioning module 2 is a gasifier, and the dual-effect reduction synergistic solidification heavy metal module 4 is a reduction tower. The gasifier has the same structure as the reduction tower, wherein the gasifier is as shown in FIG. Figure 2As shown, it includes a shell and a support structure, the support structure is arranged on the cross section of the shell, the support structure is a mesh support structure 8, and the shell is provided with a gas inlet 9, a gas outlet 11 and a solid inlet and outlet 10. The sulfur-containing flue gas enters from the gas inlet 9 to process the sludge powder 7, and the sludge powder 7 is used to control the atmosphere of the sulfur-containing flue gas. The regulated material passes through the mesh support structure 8 for gas-solid separation, and the conditioned gas after gas-solid separation is discharged from the gas outlet 11.

[0049] The method of adjusting the atmosphere of sulfur-containing flue gasification sludge to reduce sulfur and nitrate and solidify heavy metals is as follows:

[0050] The mercury-containing sludge was dried at 105℃ for 12h and then crushed into powder with a mesh size of 40-80. The powder was then placed in a gasifier and the flue gas was introduced. 2 The concentration is 10000ppm, O 2 The temperature in the gasifier is set to 800℃. After the powder is preheated to this temperature, the sludge and O 2 The reaction generates CO. The contact reaction time between the sludge powder and the sulfur-containing flue gas is 2s. The quenched gas is then passed into a reduction tower containing pyrite / alumina catalyst. 2 :SO 2 The reaction gas concentration was regulated by the molar ratio of NO / NOx = 2:1, the temperature was set at 550°C, and the air velocity was 5000 h -1 , under the catalytic action of the catalyst, SO 2 It is reduced to S, and sulfur vapor is condensed to obtain sulfur. In the above process, heavy metals such as mercury adsorbed in the waste activated carbon (coke) are desorbed, and the desorbed mercury reacts with sulfur vapor to form Hg + S HgS is fixed in the sulfur after condensation, and other heavy metals are discharged with the sulfur vapor and solidified in the sulfur after condensation.

[0051] The flue gas at the outlet of the reduction tower was tested, and the concentration of sulfur dioxide was 50ppm and the concentration of mercury was 0.0003mg / m 3 .

[0052] The above description is only a preferred embodiment of the present invention and is 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 adjusting the atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals, characterized in that: The sludge is made into sludge powder, and the sludge powder is treated with sulfur-containing flue gas at a set temperature to eliminate O2 in the sulfur-containing flue gas and generate CO and / or H2 to obtain a conditioning gas. Under the action of a dual-effect catalyst, the conditioning gas uses the CO and / or H2 generated in the conditioning gas to reduce sulfur oxides and nitrogen oxides in the conditioning gas to obtain nitrogen and sulfur element. At the same time, the sulfur element reacts with heavy metals in the conditioning gas to produce sulfides; Drying, crushing and screening the sludge to obtain sludge powder; During the treatment of sludge powder by sulfur-containing flue gas, the temperature is 600℃~1200℃; The dual-effect catalyst is a pyrite / iron sulfide catalyst; The temperature of the reduction reaction is 500~600℃; CO / H2 and SO2 / NO x The molar ratio is 2:0.9~1.1; After the conditioning gas reacts, gas-solid separation is carried out, and the separated gas is used to gasify the sludge powder.

2. The method for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 1, characterized in that: The particle size of sludge powder is 40~80 mesh.

3. The method for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 1, characterized in that: During the treatment of sludge powder with sulfur-containing flue gas, the temperature is 600~850℃.

4. The method for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 1, characterized in that: The sludge residue after the sludge powder is treated by sulfur-containing flue gas is used as raw material for cement production; The sulfur-containing flue gas is used to dispose of the sludge powder in the gasifier.

5. The method for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 4, characterized in that: The residence time of sulfur-containing flue gas in the gasifier is 0.5~3s.

6. A system for adjusting the atmosphere of sulfur-containing flue gasification sludge to reduce sulfur and nitrate and solidify heavy metals, characterized in that: include: A sludge pretreatment module, used to convert sludge into sludge powder; Flue gas gasification sludge conditioning module, used to treat sludge powder with sulfur-containing flue gas and eliminate O2 in the sulfur-containing flue gas while generating CO and / or H2; The dual-effect reduction and synergistic solidification heavy metal module receives the conditioning gas from the flue gas gasification sludge conditioning module and is used to catalyze the CO and / or H2 in the conditioning gas to reduce the sulfur oxides and nitrogen oxides in the conditioning gas to obtain nitrogen and sulfur. At the same time, the sulfur reacts with the heavy metals in the conditioning gas to produce sulfides. The temperature of the reduction reaction is 500~600℃; CO / H2 and SO2 / NO x The molar ratio is 2:0.9~1.1; After the conditioning gas reacts, gas-solid separation is carried out, and the separated gas is used to gasify the sludge powder.

7. The system for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 6, characterized in that: The flue gasification sludge conditioning module is a gasifier; The dual-effect reduction and synergistic solidification heavy metal module is a reduction tower.

8. The system for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 7, characterized in that: The gasifier comprises a shell and a support structure, wherein the support structure is arranged on the cross section of the shell and is a mesh support structure. The shell is provided with a gas inlet, a gas outlet and a solid inlet, and the support structure is located between the gas inlet and the gas outlet.

9. The system for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 6, characterized in that: It includes a rotary kiln module, part of the raw materials of which are sludge residues produced by a flue gas gasification sludge conditioning module.

10. The system for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 6, characterized in that: It includes an exhaust gas treatment module, which is used to purify the exhaust gas after condensation to meet the emission standards.

11. The system for adjusting atmosphere by gasifying sludge from sulfur-containing flue gas to reduce sulfur and nitrate and solidify heavy metals as claimed in claim 10, characterized in that: The gas phase outlet of the tail gas treatment module is connected to the gas inlet of the flue gas gasification sludge conditioning module.

12. Use of the method according to any one of claims 1 to 5 or the system according to any one of claims 6 to 11 in treating urban solid waste or carbon-containing industrial solid waste, replacing the sludge in the method or system with the urban solid waste or carbon-containing industrial solid waste.

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