Vacuum dehydration device and dehydration treatment system and method for desulfurized gypsum

Abstract

The invention relates to the technical field of desulfurization slurry treatment, and discloses a vacuum dehydration device and a dehydration treatment system and method for desulfurization gypsum. The device comprises a belt conveyor, filter cloth is arranged on the belt conveyor, a filter assisting component is arranged above the filter cloth, and the filter assisting component can extend into a filter cake layer on the filter cloth and damage a surface air blocking layer on the top of the filter cake layer. According to the technical scheme provided by the invention, the surface air barrier layer at the top of the filter cake layer is destroyed by the filter aid part, and the air pressure difference formed on the two sides of the filter cake layer due to suction filtration is recovered, so that free moisture in gypsum slurry is separated from the gypsum slurry under the dual effects of pushing force generated by the air pressure difference and self gravity; the desulfurized gypsum with relatively low water content is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurization slurry treatment, and in particular to a vacuum dehydration device and a desulfurization gypsum dehydration treatment system and method. Background Art

[0002] my country's energy structure is dominated by coal. According to statistics, from 1978 to 2009, the average proportion of coal in total energy consumption was 72.4%, reaching a peak in 2011 and declining year by year, and dropped to 55.3% in 2023. Under the dual carbon goals, the proportion of coal in the energy structure has gradually decreased, and it is changing from the main energy source to the regulating power source; but due to the instability of renewable energy such as wind power and photovoltaics, coal-fired power is still an indispensable and important part of my country's energy. Coal-fired power plants are large consumers of coal and the main source of SO2 emissions. Controlling the emission of SO2 from coal-fired power plants is of great significance to SO2 emission reduction.

[0003] Flue gas desulfurization is the main means to reduce sulfur dioxide emissions. Among various flue gas desulfurization processes, limestone-gypsum wet flue gas desulfurization is the most widely used desulfurization technology with its mature technology, stable operation, high desulfurization efficiency, abundant sources of desulfurizers and low prices. It has a market share of over 92%. In the absorption tower, SO2 in the flue gas reacts chemically with calcium carbonate in the limestone and oxygen blown in by the oxidation fan to form calcium sulfate. The main reaction process includes four steps: absorption of SO2, dissolution of limestone, oxidation of sulfite and crystallization of gypsum. In the absorption tower, as the desulfurization reaction proceeds, gypsum is continuously generated, and the slurry density of the absorption tower does not increase. When the slurry density exceeds a certain value (usually set to 1150-1200kg / m 3 ), the gypsum generated by the reaction needs to be discharged from the absorption tower in time to ensure the continuous operation of the desulfurization device.

[0004] In actual operation, most of the fine particles (fine dust captured from flue gas, impurities brought in by limestone raw materials, and small-sized gypsum crystals generated by desulfurization reaction) return to the absorption tower with the overflow slurry of the gypsum cyclone, but some fine particles still enter the vacuum dehydrator with the bottom flow slurry of the gypsum cyclone; the higher the fine particle content in the tower, the greater the amount of fine particles entering the vacuum dehydrator with the bottom flow slurry of the gypsum cyclone. Due to the light weight and small particle size of fine particles, their sedimentation performance is significantly lower than that of large-particle gypsum; when the bottom flow slurry of the gypsum cyclone is distributed from the feed distributor to the filter cloth, the light-weight and small-sized fine particles are mostly enriched on the top of the gypsum filter cake layer, forming a dense fine particle surface gas barrier layer; the more fine particles there are, the worse the air permeability of the surface gas barrier layer; the greater the viscosity of the slurry, the worse the air permeability. Because there is a gas barrier layer on the top of the gypsum filter cake, the air permeability of the gypsum filter cake is poor, and the atmospheric pressure cannot act on the gypsum crystals inside the filter cake layer. When the pressure inside the filter cake layer is the same as the negative pressure generated by the vacuum pump, the only force driving the free water to separate from the gypsum filter cake is gravity, and the separation effect is greatly reduced, and the moisture content of the gypsum continues to increase. Too high a moisture content not only increases the cost of drying in the transportation and comprehensive utilization of gypsum, but the chloride ions dissolved in the water will also increase the chloride ion content of the gypsum, affecting the quality of the gypsum and the scope of comprehensive utilization. Summary of the invention

[0005] The purpose of the present invention is to overcome the problem in the prior art that fine particles in the gypsum slurry are enriched on the gypsum filter cake layer to form a gas barrier layer with poor air permeability, resulting in a high water content of the desulfurized gypsum after dehydration, and to provide a vacuum dehydration device and a desulfurized gypsum dehydration treatment system and method. The vacuum dehydration device and the desulfurized gypsum dehydration treatment system and method of the present invention can destroy the surface gas barrier layer on the top of the filter cake layer through a filter-aiding component, restore the air pressure difference formed on both sides of the filter cake layer due to suction filtration, so that the free water in the gypsum slurry is separated from the gypsum slurry under the dual effects of the driving force generated by the air pressure difference and its own gravity, and obtain desulfurized gypsum with a lower water content.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a vacuum dehydration device on one hand, which includes: a belt conveyor, a filter cloth is arranged on the belt conveyor, and a filter aid component is arranged above the filter cloth, and the filter aid component can extend into the filter cake layer on the filter cloth and destroy the surface gas barrier layer on the top of the filter cake layer.

[0007] Preferably, the filter-aiding component is a comb-type grid structure.

[0008] Preferably, the thickness of the comb-shaped grid structure is 0.1-5 mm, and the interval between two adjacent ones is 3-20 mm.

[0009] Preferably, the comb-shaped grid structure is made of at least one of plastic, fiberglass and stainless steel.

[0010] Preferably, the angle between the comb-shaped grid structure and the surface of the filter cloth is 45-135°.

[0011] Preferably, the top of the comb-shaped grid structure extends into the filter cake layer to a depth of 0.1-3 mm.

[0012] Preferably, support rods are provided on both sides of the filter cloth, and the filter aid component is arranged above the filter cloth through the support rods.

[0013] Preferably, a height adjustment bar is provided on the support rod, and the height adjustment bar can adjust the installation height of the filter aid component.

[0014] A second aspect of the present invention provides a desulfurization gypsum dehydration treatment system, which includes an absorption tower, a gypsum cyclone and a vacuum dehydration device. A desulfurization reaction occurs in the absorption tower and a slurry containing gypsum is generated. The slurry containing gypsum is separated in the gypsum cyclone, and the separated underflow slurry enters the vacuum dehydration device for vacuum dehydration.

[0015] The third aspect of the present invention provides a dehydration method for desulfurized gypsum, the method comprising: a desulfurization reaction occurs in the absorption tower to generate a slurry containing gypsum; when the density of the slurry in the absorption tower 1 rises to 1150 kg / m 3 In the above process, the slurry containing gypsum is transported to the gypsum cyclone for separation; and the underflow slurry separated from the gypsum cyclone is transported to a vacuum dehydration device for vacuum dehydration.

[0016] Preferably, when the slurry density in the absorption tower rises to 1150-1200 kg / m 3 When the slurry containing gypsum is transported to the gypsum cyclone for separation.

[0017] Preferably, the method further comprises: returning the overflow slurry from the upper part of the gypsum cyclone to the absorption tower 1 to continue to participate in the desulfurization reaction.

[0018] Preferably, the method further comprises: when the chloride ion concentration in the slurry in the absorption tower exceeds 20000 mg / L, transporting part of the overflow slurry on the upper part of the gypsum cyclone to a wastewater treatment device for subsequent treatment, and subjecting the treated wastewater to comprehensive utilization or deep zero emission treatment.

[0019] According to the vacuum dehydration device and the dehydration treatment system and method of desulfurized gypsum of the present invention, the surface gas barrier layer on the top of the filter cake layer is destroyed by the filter-aiding component, and the air pressure difference formed on both sides of the filter cake layer due to the suction filtration is restored, so that the free water in the gypsum slurry is separated from the gypsum slurry under the dual effects of the driving force generated by the air pressure difference and its own gravity, and desulfurized gypsum with a low water content is obtained. The vacuum dehydration device and the dehydration treatment system and method of desulfurized gypsum are simple, convenient, and highly applicable, and have a positive effect on improving the quality of desulfurized gypsum. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the dehydration treatment system of desulfurized gypsum according to the present invention; Figure 2 is a schematic diagram of the arrangement of the filter aid component of the present invention in the vacuum dehydration device; Figure 3 is a schematic diagram of a height adjustment method of the filter aid component of the present invention; Figure 4 is a top view of the gypsum filter cake of Comparative Example 1 of the present invention; Figure 5 is a cross-sectional view of the gypsum filter cake of Comparative Example 1 of the present invention; Figure 6 This is a microscopic electron microscope photograph of the bottom of the gypsum filter cake of Comparative Example 1 of the present invention (magnification 200 times); Figure 7 This is a microscopic electron microscope photograph of the gas barrier layer on the surface of the gypsum filter cake of Comparative Example 1 of the present invention (magnification 200 times).

[0021] Description of Reference Numerals 1. Absorption tower; 2. Gypsum discharge pump; 3. Adjustment gate; 4. Gypsum cyclone; 5. Wastewater treatment device; 6. Vacuum dehydration device; 61. Filter cloth; 62. Belt conveyor; 63. Filter aid component; 64. Comb-type grid structure; 7. Filtrate water tank; 8. Gypsum material pile; 9. Feed distributor; 10. Support rod; 11. Height adjustment bar. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0023] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0024] In the present invention, "plurality" means two or more. The term "comprising" and any variation thereof are intended to be non-exclusive, and one or more other features, integers, steps, operations, units, components and / or combinations thereof may exist or be added.

[0025] In addition, terms indicating orientation or positional relationships, such as “upper”, “lower”, “top”, “bottom”, “inside” and “outside”, are described based on the orientation or relative positional relationships shown in the drawings and are merely simplified descriptions for the convenience of describing the present application. They do not indicate that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation and therefore should not be construed as limitations on the present application.

[0026] In addition, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection through an intermediate medium, or the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] like Figure 1 and Figure 2 As shown, the vacuum dehydration device described in the present invention includes a belt conveyor 61, on which a filter cloth 62 is arranged, and above the filter cloth 62 a filter aid component 63 is arranged, and the filter aid component 63 can extend into the filter cake layer on the filter cloth 62 and destroy the surface gas barrier layer on the top of the filter cake layer.

[0028] According to the vacuum dehydration device of the present invention, after the gypsum slurry is transported to the belt conveyor 61, the free water in the gypsum slurry is separated under the dual effects of its own gravity and the driving force generated by the air pressure difference, and the filter cake layer moves to the tail discharge port with the filter cloth. The filter aid component 63 increases the pressure difference on both sides of the filter cake layer by destroying the surface air barrier layer on the top of the filter cake layer, so that the free water in the gypsum slurry is separated under the dual effects of its own gravity and the driving force generated by the air pressure difference, and desulfurized gypsum with a lower dehydration rate is obtained. This technical solution has the advantages of high gypsum slurry treatment efficiency and sustainable stability.

[0029] In the vacuum dehydration device of the present invention, preferably, the filter aid component 63 may be a comb-shaped grid structure 64. The thickness of the comb-shaped grid structure 64 may be 0.1-5 mm, preferably 1-3 mm; the spacing between two adjacent comb-shaped grid structures 64 may be 3-20 mm, preferably 5-10 mm.

[0030] In the vacuum dehydration device of the present invention, the material of the filter aid component 63 can be at least one of plastic, fiberglass and stainless steel. In the most preferred embodiment, the material of the filter aid component 63 is stainless steel.

[0031] In the vacuum dehydration device of the present invention, the angle between the comb-shaped grid structure 64 and the surface of the filter cloth 62 can be 45-135°. In the most preferred embodiment, the angle between the comb-shaped grid structure 64 and the surface of the filter cloth 62 is 90°. According to this preferred embodiment, the vacuum dehydration device 6 has a higher dehydration efficiency.

[0032] In the vacuum dehydration device of the present invention, the top of the comb-shaped grid structure 64 may extend into the filter cake layer to a depth of 0.1-3 mm, preferably 1-2 mm.

[0033] In the vacuum dehydration device of the present invention, support rods 10 are provided on both sides of the filter cloth 62, and the filter aid component 63 is provided above the filter cloth 62 through the support rods 10. A height adjustment bar 11 is provided on the support rod 10, and the height adjustment bar 11 can adjust the installation height of the filter aid component 63. According to this structural design, the filter aid component 63 is easy to install and remove.

[0034] In the vacuum dehydration device of the present invention, the filter aid component 63 can be provided as one or more sets, preferably multiple sets, and more preferably 3 sets. In a more preferred embodiment, when the vacuum dehydration device 6 is provided with multiple sets of the filter aid component 63, the grid plates of adjacent filter aid components 63 are arranged on the vacuum dehydration device 6 in a staggered manner, that is, the action positions of the grid plates of adjacent filter aid components 63 on the filter cloth 62 do not completely overlap.

[0035] In the vacuum dehydration device of the present invention, the vacuum dehydration device 6 further comprises a feed distributor 9 , which is arranged above the filter cloth 62 , and the underflow slurry is transported to the filter cloth 62 by the feed distributor 9 .

[0036] like Figure 1 As shown, the desulfurization gypsum dehydration treatment system of the present invention includes an absorption tower 1, a gypsum cyclone 4 and a vacuum dehydration device 6. A desulfurization reaction occurs in the absorption tower 1 and a slurry containing gypsum is generated. The slurry containing gypsum is separated in the gypsum cyclone 4, and the separated underflow slurry enters the vacuum dehydration device 6 for vacuum dehydration.

[0037] In the dehydration treatment system of desulfurized gypsum of the present invention, the absorption tower 1 is connected to the gypsum cyclone 4, and a gypsum discharge pump 2 and a regulating gate 3 are provided between the absorption tower 1 and the gypsum cyclone 4. In a preferred case, the connecting pipeline between the absorption tower 1 and the absorption tower 4 is connected to the absorption tower 1, and the connecting pipeline between the absorption tower 1 and the absorption tower 4 and the connecting pipeline of the absorption tower 1 are provided with the regulating gate 3, which is used to adjust the pressure of the connecting pipeline between the absorption tower 1 and the absorption tower 4, so that the slurry containing gypsum can be efficiently and stably transported from the absorption tower 1 to the gypsum cyclone 4.

[0038] In the desulfurized gypsum dehydration treatment system of the present invention, the gypsum cyclone 4 is connected to the wastewater treatment device 5. A chloride ion concentration detection device is arranged inside the absorption tower 1. When the chloride ion concentration of the gypsum-containing slurry exceeds the target concentration, the gypsum-containing slurry is transported to the wastewater treatment device 5 for treatment.

[0039] In the desulfurized gypsum dehydration treatment system of the present invention, a filtrate water tank 7 is provided at the bottom of the vacuum dehydration device 6. The filtrate separated after being treated by the vacuum dehydration device 6 is stored in the filtrate water tank 7.

[0040] The desulfurized gypsum dehydration treatment method of the present invention is implemented in the desulfurized gypsum dehydration treatment system, and the method comprises: A desulfurization reaction occurs in the absorption tower 1 to generate a slurry containing gypsum; The slurry density in the absorption tower 1 rises to 1150 kg / m 3 When the above, the slurry containing gypsum is transported to the gypsum cyclone 4 for separation; The underflow slurry separated from the gypsum cyclone 4 is transported to the vacuum dehydration device 6 for vacuum dehydration.

[0041] In the method of the present invention, in a preferred embodiment, when the density of the slurry in the absorption tower 1 rises to 1150-1200 kg / m 3 When the slurry containing gypsum is transported to the gypsum cyclone 4 for separation.

[0042] In the present invention, the dehydration treatment method of desulfurized gypsum may further include: returning the overflow slurry on the upper part of the gypsum cyclone 4 to the absorption tower 1 to continue to participate in the desulfurization reaction.

[0043] In the present invention, the dehydration treatment method of desulfurized gypsum may also include: when the chloride ion concentration in the slurry in the absorption tower 1 exceeds 20,000 mg / L, part of the overflow slurry on the top of the gypsum cyclone 4 is transported to the wastewater treatment device 5 for subsequent treatment, and the treated wastewater is comprehensively utilized or subjected to deep zero emission treatment.

[0044] The vacuum dehydration device and the desulfurized gypsum dehydration treatment system and method of the present invention are further described below by examples. The examples are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following examples.

[0045] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0046] Example 1 The dehydration treatment system of desulfurized gypsum in this embodiment includes an absorption tower 1, a gypsum discharge pump 2, an adjusting gate 3, a gypsum cyclone 4, a wastewater treatment device 5, a vacuum dehydration device 6, a filtrate water tank 7, and a feed distributor 9; the vacuum dehydration device includes a belt conveyor 61, a filter cloth 62, a filter aid component 63, a support rod 10, and a height adjustment bar 11. A chloride ion concentration detection device is arranged inside the absorption tower 1. The absorption tower 1 is connected to the gypsum cyclone 4, and a gypsum discharge pump 2 and an adjusting gate 3 are arranged between the absorption tower 1 and the gypsum cyclone 4. The connecting pipeline between the absorption tower 1 and the absorption tower 4 is connected to the absorption tower 1, and the connecting pipeline between the absorption tower 1 and the absorption tower 4 and the connecting pipeline of the absorption tower 1 are provided with an adjusting gate 3. The gypsum cyclone 4 is connected to the wastewater treatment device 5. A feed distributor 9 is arranged at the bottom of the gypsum cyclone 4, and a vacuum dehydration device 6 is arranged below the feed distributor 9. A filtrate water tank 7 is arranged at the bottom of the vacuum dehydration device 6. A filter cloth 62 is provided on the belt conveyor 61, and a filter aid component 63 is provided above the filter cloth 62. The filter aid component 63 is a comb-shaped grid structure 64, made of stainless steel, with a grid plate thickness of 2 mm, and a spacing of 5 mm between two adjacent comb-shaped structures. The filter aid component 63 is fixed on the support platform of the filter cloth 62, with an angle of 90° between the filter cloth 62 and the surface of the filter cloth 62. There are three sets of filter aid components 63, and the grid plates of the filter aid components 63 are arranged in a staggered manner on the vacuum dehydration device 6.

[0047] In the specific implementation process, in the absorption tower 1, as the desulfurization reaction proceeds, the density of the slurry containing gypsum in the absorption tower 1 continues to increase. When the density rises to 1167kg / m 3When (the chloride ion concentration of the slurry containing gypsum in the absorption tower 1 is 21325 mg / L, when the chloride ion concentration of the slurry containing gypsum in the absorption tower 1 exceeds 20000 mg / L, part of the overflow slurry is transported to the wastewater treatment device 5 for subsequent treatment), the slurry containing gypsum enters the gypsum cyclone 4 from the gypsum discharge pump 2 for separation, and the bottom flow slurry with large particle size and high density enters the vacuum dehydration device 6 through the feed distributor 9 for vacuum dehydration. The dehydrated gypsum is transported to the gypsum pile 8 by the filter cloth 62, and the separated free water is stored in the filtrate water tank 7 (transported to the absorption tower 1 for reuse). During the vacuum dehydration process, by adjusting the height adjustment bar 11 on the support rod 10 of the filter aid component 63, the depth of the top of the filter aid component extending into the filter cake layer is controlled to be 1 mm. According to the above embodiment, desulfurized gypsum A1 is obtained.

[0048] The moisture content and chloride ion content of desulfurized gypsum A1 were tested, and the moisture content was 11.2wt% and the chloride ion content was 0.40wt%.

[0049] Example 2 The dehydration treatment system of desulfurized gypsum in this embodiment includes an absorption tower 1, a gypsum discharge pump 2, an adjusting gate 3, a gypsum cyclone 4, a wastewater treatment device 5, a vacuum dehydration device 6, a filtrate water tank 7, and a feed distributor 9; the vacuum dehydration device includes a belt conveyor 61, a filter cloth 62, a filter aid component 63, a support rod 10, and a height adjustment bar 11. A chloride ion concentration detection device is arranged inside the absorption tower 1. The absorption tower 1 is connected to the gypsum cyclone 4, and a gypsum discharge pump 2 and an adjusting gate 3 are arranged between the absorption tower 1 and the gypsum cyclone 4. The connecting pipeline between the absorption tower 1 and the absorption tower 4 is connected to the absorption tower 1, and the connecting pipeline between the absorption tower 1 and the absorption tower 4 and the connecting pipeline of the absorption tower 1 are provided with an adjusting gate 3. The gypsum cyclone 4 is connected to the wastewater treatment device 5. A feed distributor 9 is arranged at the bottom of the gypsum cyclone 4, and a vacuum dehydration device 6 is arranged below the feed distributor 9. A filtrate water tank 7 is arranged at the bottom of the vacuum dehydration device 6. A filter cloth 62 is provided on the belt conveyor 61, and a filter aid component 63 is provided above the filter cloth 62. The filter aid component 63 is a comb-shaped grid structure 64, made of stainless steel, with a grid plate thickness of 3 mm, and a spacing of 8 mm between two adjacent comb-shaped structures. The filter aid component 63 is fixed on the support platform of the filter cloth 62, with an angle of 90° between the filter cloth 62 and the surface of the filter cloth 62, and there are three sets of the filter aid component 63, and the grid plates of the filter aid component 63 are arranged in a staggered manner on the vacuum dehydration device 6.

[0050] In the specific implementation process, in the absorption tower 1, as the desulfurization reaction proceeds, the density of the slurry containing gypsum in the absorption tower 1 continues to increase. When the density rises to 1180kg / m 3When (the chloride ion concentration of the slurry containing gypsum in the absorption tower 1 is 20763 mg / L, when the chloride ion concentration of the slurry containing gypsum in the absorption tower 1 exceeds 20000 mg / L, part of the overflow slurry is transported to the wastewater treatment device 5 for subsequent treatment), the slurry containing gypsum enters the gypsum cyclone 4 from the gypsum discharge pump 2 for separation, and the bottom flow slurry with large particle size and high density enters the vacuum dehydration device 6 through the feed distributor 9 for vacuum dehydration. The dehydrated gypsum is transported to the gypsum pile 8 by the filter cloth 62, and the separated free water is stored in the filtrate water tank 7 (transported to the absorption tower 1 for reuse). During the vacuum dehydration process, by adjusting the height adjustment bar 11 on the support rod 10 of the filter aid component 63, the depth of the top of the filter aid component extending into the filter cake layer is controlled to be 1.5 mm. According to the above embodiment, desulfurized gypsum A2 is obtained.

[0051] The moisture content and chloride ion content of desulfurized gypsum A2 were tested, and the moisture content was 11.5wt% and the chloride ion content was 0.42wt%.

[0052] Example 3 The dehydration treatment system of desulfurized gypsum in this embodiment includes an absorption tower 1, a gypsum discharge pump 2, an adjusting gate 3, a gypsum cyclone 4, a wastewater treatment device 5, a vacuum dehydration device 6, a filtrate water tank 7, and a feed distributor 9; the vacuum dehydration device includes a belt conveyor 61, a filter cloth 62, a filter aid component 63, a support rod 10, and a height adjustment bar 11. A chloride ion concentration detection device is arranged inside the absorption tower 1. The absorption tower 1 is connected to the gypsum cyclone 4, and a gypsum discharge pump 2 and an adjusting gate 3 are arranged between the absorption tower 1 and the gypsum cyclone 4. The connecting pipeline between the absorption tower 1 and the absorption tower 4 is connected to the absorption tower 1, and the connecting pipeline between the absorption tower 1 and the absorption tower 4 and the connecting pipeline of the absorption tower 1 are provided with an adjusting gate 3. The gypsum cyclone 4 is connected to the wastewater treatment device 5. A feed distributor 9 is arranged at the bottom of the gypsum cyclone 4, and a vacuum dehydration device 6 is arranged below the feed distributor 9. A filtrate water tank 7 is arranged at the bottom of the vacuum dehydration device 6. A filter cloth 62 is provided on the belt conveyor 61, and a filter aid component 63 is provided above the filter cloth 62. The filter aid component 63 is a comb-shaped grid structure 64, made of stainless steel, with a grid plate thickness of 1 mm, and a spacing of 10 mm between two adjacent comb-shaped structures. The filter aid component 63 is fixed on the support platform of the filter cloth 62, with an angle of 90° between the filter cloth 62 and the surface of the filter cloth 62. There are three sets of filter aid components 63, and the grid plates of the filter aid components 63 are arranged in a staggered manner on the vacuum dehydration device 6.

[0053] In the specific implementation process, in the absorption tower 1, as the desulfurization reaction proceeds, the density of the slurry containing gypsum in the absorption tower 1 continues to increase. When the density rises to 1150kg / m 3When (the chloride ion concentration of the slurry containing gypsum in the absorption tower 1 is 22128 mg / L, when the chloride ion concentration of the slurry containing gypsum in the absorption tower 1 exceeds 20000 mg / L, part of the overflow slurry is transported to the wastewater treatment device 5 for subsequent treatment), the slurry containing gypsum enters the gypsum cyclone 4 from the gypsum discharge pump 2 for separation, and the bottom flow slurry with large particle size and high density enters the vacuum dehydration device 6 through the feed distributor 9 for vacuum dehydration. The dehydrated gypsum is transported to the gypsum pile 8 by the filter cloth 62, and the separated free water is stored in the filtrate water tank 7 (transported to the absorption tower 1 for reuse). During the vacuum dehydration process, by adjusting the height adjustment bar 11 on the support rod 10 of the filter aid component 63, the depth of the top of the filter aid component extending into the filter cake layer is controlled to be 1 mm. According to the above embodiment, desulfurized gypsum A3 is obtained.

[0054] The moisture content and chloride ion content of desulfurized gypsum A3 were tested, and the moisture content was 11.4wt% and the chloride ion content was 0.43wt%.

[0055] Example 4 Dehydrated gypsum is produced according to the vacuum dehydration device and the desulfurized gypsum dehydration treatment system and method of Example 1, except that the grid thickness of the filter aid is adjusted to 1 mm, and the spacing between two adjacent comb-type grid structures is adjusted to 15 mm.

[0056] During the vacuum dehydration process, the depth of the top of the filter-aid component extending into the filter cake layer was adjusted to 1.5 mm to obtain desulfurized gypsum A4.

[0057] The moisture content and chloride ion content of desulfurized gypsum A4 were tested, and the moisture content was 12.5wt% and the chloride ion content was 0.49wt%.

[0058] Example 5 Dehydrated gypsum is produced according to the vacuum dehydration device and the desulfurized gypsum dehydration treatment system and method of Example 1, except that the grid thickness of the filter aid is adjusted to 1 mm, and the spacing between two adjacent comb-type grid structures is adjusted to 10 mm.

[0059] During the vacuum dehydration process, the depth of the top of the filter-aid component extending into the filter cake layer was adjusted to 0.5 mm to obtain desulfurized gypsum A5.

[0060] The moisture content and chloride ion content of desulfurized gypsum A5 were tested, and the moisture content was 12.3wt% and the chloride ion content was 0.50wt%.

[0061] Comparative Example 1 Dehydrated gypsum is produced according to the vacuum dehydration device and the desulfurized gypsum dehydration treatment system and method of Example 1, except that the filter aid component 63 is not installed on the vacuum dehydration device 6, and desulfurized gypsum D1 is obtained. Figure 4 This is a top view of the gypsum filter cake of the desulfurized gypsum D1 in this embodiment. Figure 5 This is a cross-sectional view of the gypsum filter cake of the desulfurized gypsum D1 in this embodiment. Figure 6 This is a microscopic electron microscope photo of the bottom of the gypsum filter cake of the desulfurized gypsum D1 in this embodiment (magnification 200 times), Figure 7 This is a microscopic electron microscope photograph of the gas barrier layer on the surface of the gypsum filter cake of the desulfurized gypsum D1 in this example (magnification 200 times).

[0062] The desulfurized gypsum D1 was tested for moisture content and chloride ion content, and the moisture content was 20.2wt% and the chloride ion content was 0.71wt%.

[0063] The corresponding operating conditions of the above-mentioned embodiments and comparative examples and the performance parameters of the moisture content of the gypsum after dehydration are shown in Table 1.

[0064] Table 1

[0065] It can be seen from the results in Table 1 that the vacuum dehydration device and the desulfurization gypsum dehydration treatment system and method according to the present invention can obtain desulfurization gypsum with significantly lower water content.

[0066] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A vacuum dehydration device, characterized in that: The vacuum dehydration device comprises a belt conveyor (61), a filter cloth (62) being arranged on the belt conveyor (61), a filter aid component (63) being arranged above the filter cloth (62), and the filter aid component (63) being capable of extending into a filter cake layer on the filter cloth (62) and destroying a surface gas barrier layer on the top of the filter cake layer.

2. The vacuum dehydration device according to claim 1, characterized in that: The filter-aiding component (63) is a comb-shaped grid structure (64).

3. The vacuum dehydration device according to claim 2, characterized in that: The thickness of the comb-shaped grille (64) structure is 0.1-5 mm, and the spacing between two adjacent ones is 3-20 mm.

4. The vacuum dehydration device according to any one of claims 1 to 3, characterized in that: The material of the comb-shaped grille structure (64) is at least one of plastic, glass fiber reinforced plastic and stainless steel.

5. The vacuum dehydration device according to any one of claims 1 to 3, characterized in that: The included angle between the comb-shaped grid structure (64) and the surface of the filter cloth (62) is 45-135°.

6. The vacuum dehydration device according to any one of claims 1 to 3, characterized in that: The top end of the comb-shaped grid structure (64) extends into the filter cake layer to a depth of 0.1-3 mm.

7. The vacuum dehydration device according to any one of claims 1 to 6, characterized in that: Support rods (10) are arranged on both sides of the filter cloth (62), and the filter aid component (63) is arranged above the filter cloth (62) via the support rods (10).

8. The vacuum dehydration device according to claim 7, characterized in that: The support rod (10) is provided with a height adjustment bar (11), and the height adjustment bar (11) is capable of adjusting the installation height of the filter aid component (63).

9. A desulfurized gypsum dehydration treatment system, characterized in that: The system comprises an absorption tower (1), a gypsum cyclone (4) and a vacuum dehydration device (6). A desulfurization reaction occurs in the absorption tower (1) and generates a slurry containing gypsum. The slurry containing gypsum is separated in the gypsum cyclone (4). The separated underflow slurry enters the vacuum dehydration device (6) for vacuum dehydration, wherein the vacuum dehydration device (6) is the vacuum dehydration device according to any one of claims 1 to 8.

10. A dehydration method for desulfurized gypsum, characterized in that: The method is implemented in the desulfurized gypsum dehydration treatment system according to claim 9, and the method comprises: A desulfurization reaction occurs in the absorption tower (1) to generate a slurry containing gypsum; When the density of the slurry in the absorption tower (1) rises to 1150 kg / m 3 When the above, the slurry containing gypsum is transported to the gypsum cyclone (4) for separation; The underflow slurry separated from the gypsum cyclone (4) is transported to a vacuum dehydration device (6) for vacuum dehydration.

11. The method according to claim 10, characterized in that When the density of the slurry in the absorption tower (1) rises to 1150-1200 kg / m 3 When the slurry containing gypsum is transported to the gypsum cyclone (4) for separation.

12. The method according to claim 10 or 11, characterized in that: The method further comprises: returning the overflow slurry from the upper part of the gypsum cyclone (4) to the absorption tower (1) to continue participating in the desulfurization reaction.

13. The method according to any one of claims 10 to 12, characterized in that: The method further comprises: when the chloride ion concentration in the slurry in the absorption tower (1) exceeds 20,000 mg / L, transporting part of the overflow slurry from the upper part of the gypsum cyclone (4) to a wastewater treatment device (5) for subsequent treatment, and subjecting the treated wastewater to comprehensive utilization or deep zero-discharge treatment.

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