Phosphorus resource processing system in sludge gasification slag

Abstract

The utility model relates to sludge resource utilization technical field, concretely relates to a kind of phosphorus element resource treatment system in sludge gasification slag, including acid leaching tank, the front end of acid leaching tank is connected with bunker and waste acid storage tank respectively, the rear end of acid leaching tank is connected with first centrifuge, and the acid leaching residue separated by first centrifuge is transported to the alkali leaching tank of rear end, the rear end of alkali leaching tank is connected with second centrifuge, and the alkali leaching solution separated by second centrifuge is transported to the alkali leaching solution storage tank of rear end, the rear end of alkali leaching solution storage tank is connected with reaction tank, the front end of reaction tank is also connected with calcium chloride storage tank and sodium hydroxide storage tank respectively, the rear end of reaction tank is connected with third centrifuge, and the solid material separated by third centrifuge is calcium phosphate product after drying and crushing. The utility model can realize the comprehensive utilization of sludge gasification slag and waste acid, realize the extraction of phosphorus element in sludge gasification slag, and have important significance to resource recovery and environmental protection.

Description

Technical Field

[0001] This utility model relates to the field of sludge resource utilization technology, specifically to a system for the resource utilization of phosphorus in sludge gasification residue. Background Technology

[0002] The biological treatment of municipal sewage generates a large amount of sludge. If left untreated, it will not only waste resources but also pollute the environment. Existing methods such as sludge fermentation, concentration, dewatering, drying, and pyrolysis gasification are used to reduce the volume of sludge and make it a resource. This is of great significance for resource recovery and environmental protection.

[0003] After sludge pyrolysis and gasification, sludge gasification residue is produced. This residue contains abundant phosphorus, which, if not properly utilized, would undoubtedly lead to resource loss. Therefore, this invention develops a phosphorus resource recovery system for sludge gasification residue, which recovers phosphorus from the residue in the form of calcium phosphate, thereby achieving phosphorus resource recovery and utilization. It also facilitates the further utilization of wastewater from the desulfurization tower in the sludge gasification tail gas, making it suitable for industrial application and promotion. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of the existing technology by providing a system for the resource-based treatment of phosphorus in sludge gasification residue, so as to achieve the goal of recovering and utilizing phosphorus in sludge gasification residue.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a phosphorus resource utilization system for sludge gasification residue, comprising an acid leaching tank, the front end of which is connected to a silo and a waste acid storage tank, the rear end of which is connected to a first centrifuge, the acid leaching residue separated by the first centrifuge being transported to a rear alkaline leaching tank, the rear end of which is connected to a second centrifuge, the alkaline leaching liquid separated by the second centrifuge being transported to a rear alkaline leaching liquid storage tank, the rear end of which is connected to a reaction tank, the front end of which is also connected to a calcium chloride storage tank and a sodium hydroxide storage tank, and the rear end of which is connected to a third centrifuge.

[0006] Furthermore, a crusher is installed at the front end of the silo, and the crushed material of the sludge gasification residue is stored in the silo after being crushed by the crusher.

[0007] Furthermore, each of the acid leaching tank, alkali leaching tank, and reaction tank is equipped with a stirrer.

[0008] Furthermore, the sodium hydroxide storage tank is connected to the alkali leaching tank.

[0009] Furthermore, a drying device and a pulverizer are sequentially installed at the rear end of the third centrifuge.

[0010] Furthermore, the silo and the acid leaching tank are connected by a screw conveyor, and a control valve and a metering pump are installed on the connecting pipe between the waste acid storage tank and the acid leaching tank.

[0011] Furthermore, the rear end of the first centrifuge is connected to the alkali leaching tank via a screw conveyor, and a control valve and a metering pump are installed on the connecting pipe between the sodium hydroxide storage tank and the alkali leaching tank.

[0012] Furthermore, a control valve and a metering pump are installed on the connecting pipe between the alkali leaching solution storage tank and the reaction tank; a control valve and a metering pump are installed on the connecting pipe between the calcium chloride storage tank and the reaction tank; a control valve and a delivery pump are installed on the connecting pipe between the sodium hydroxide storage tank and the reaction tank; an online pH meter is installed in the reaction tank, and the online pH meter is linked to the delivery pump.

[0013] The beneficial effects of this utility model are: This utility model can realize the comprehensive utilization of sludge gasification residue and waste acid, and realize the extraction of phosphorus from sludge gasification residue, which is of great significance for resource recycling and environmental protection. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structural layout of this utility model.

[0015] The names corresponding to each mark in the diagram: 1. Crusher; 2. Silo; 3. Waste acid storage tank; 4. Acid leaching tank; 5. First centrifuge; 6. Alkali leaching tank; 7. Second centrifuge; 8. Alkali leaching solution storage tank; 9. Sodium hydroxide storage tank; 10. Calcium chloride storage tank; 11. Reaction tank; 12. Third centrifuge; 13. Drying equipment; 14. Pulverizer. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model are within the protection scope of the present utility model.

[0017] Embodiments of this utility model: like Figure 1As shown, in this embodiment, the sludge gasification residue is crushed by crusher 1, and the resulting crushed material is transported to silo 2. Waste acid is stored in waste acid storage tank 3, and the waste acid reacts with the crushed material in silo 2 in acid leaching tank 4. In another embodiment of this utility model, the sludge gasification residue is crushed by jaw crusher 1, and the resulting crushed material is transported to silo 2 by belt conveyor, and then metered and transported to acid leaching tank 4 by screw conveyor in silo 2. Both waste acid storage tank 3 and acid leaching tank 4 are equipped with agitators. The waste acid in waste acid storage tank 3 is transported to acid leaching tank 4 by metering pump. The waste acid is the wastewater from the desulfurization tower of municipal sludge gasification tail gas, which mainly includes sulfuric acid and nitric acid. The percentage content of sulfuric acid and nitric acid is about 20%, and the percentage content of sulfuric acid and nitric acid is about 2~3:1. The solid-liquid ratio of crushed material to waste acid is 1:10~20 (kg / L).

[0018] After the crushed material and waste acid are fully reacted in the acid leaching tank 4, they are transported to the first centrifuge 5 by a transfer pump. Solid-liquid separation is carried out in the first centrifuge 5, and the separated acid leaching residue is transported to the alkali leaching tank 6. The alkali leaching tank 6 is connected to the sodium hydroxide solution storage tank. The sodium hydroxide solution storage tank supplies sodium hydroxide solution to the alkali leaching tank 6 via a metering transfer pump. An agitator is installed in the alkali leaching tank 6. After the reaction is fully reacted, the solution is transported to the second centrifuge 7 by a transfer pump. The alkali leaching liquid obtained by centrifugation is transported to the alkali leaching liquid storage tank 8 by a transfer pump. In one embodiment of this utility model, the first centrifuge 5 is a horizontal screw centrifuge. The acid leaching residue obtained by centrifugation is transported to the alkali leaching tank 6 by a screw conveyor. The sodium hydroxide solution storage tank stores a sodium hydroxide solution with a concentration of 1 mol / L. The solid-liquid ratio of the acid leaching residue to the sodium hydroxide solution is 1:10~20 (kg / L). The second centrifuge 7 is a horizontal screw centrifuge.

[0019] The alkali leaching solution in alkali leaching solution storage tank 8 is connected to reaction tank 11 via a metering pump. The sodium hydroxide solution in sodium hydroxide storage tank 9 is connected to reaction tank 11 via a pump. A calcium chloride storage tank 10 is also provided, and the calcium chloride solution in the calcium chloride storage tank 10 is connected to reaction tank 11 via a metering pump. A stirrer is installed in reaction tank 11. After thorough stirring and reaction, the solution is pumped to a third centrifuge 12. The solid material separated by the third centrifuge 12 is dried by drying equipment 13 and pulverized by pulverizer 14 to obtain calcium phosphate. Product; In one embodiment of this utility model, the concentration of calcium chloride solution is 30%, the molar ratio of calcium ions to phosphate ions is 1.1~1.3:1, sodium hydroxide solution is added, and the pH in reaction tank 11 is controlled to be not lower than 10 (an online pH meter is installed in reaction tank 11, and the online pH meter is linked to the transfer pump from sodium hydroxide storage tank 9 to reaction tank 11 through a field PLC); the third centrifuge 12 is a horizontal screw centrifuge, the drying equipment 13 is a drum dryer or oven, and the pulverizer 14 includes an ultrafine pulverizer 14, etc.

[0020] The principle of this utility model is as follows: In this invention, phosphorus is extracted and recycled from municipal sludge gasification residue. During this process, calcium phosphate is prepared through a series of steps to achieve phosphorus resource recovery. The main components of the sludge gasification residue are shown in the table below. Table 1. Content of main components in sludge gasification residue (some not shown)

[0021] Specifically, the sludge gasification residue is crushed and stored in the silo (2). When used, it is metered and transported to the acid leaching tank (4). At the same time, the acidic wastewater generated by the plant's desulfurization tower is used. The acidic wastewater mainly contains sulfuric acid and nitric acid. The crushed sludge gasification residue is acid-leached with waste acid to extract soluble substances such as iron and calcium from the sludge gasification residue. The principle is as follows: Ca9(Al)(PO4)7+21H + →9Ca 2+ +Al 3+ +7H3PO4 Fe3(PO4)2+6H + →3Fe 2+ +2H3PO4 FePO4+3H + →Fe 3+ +H3PO4 During acid leaching, Ca and Fe are dissolved in acid (although sulfuric acid is present, calcium sulfate has a higher solubility in acidic conditions than water, therefore, most of the calcium will dissolve). The purpose is to completely convert Ca9(Al)(PO4)7 and FePO4 into Al phosphate precipitates. The principle is as follows: Al 3+ +H3PO4→AlPO4↓ Al 3+ +3H2PO4 - →Al(H2PO4)3↓ Therefore, during the solid-liquid separation process after acid leaching, the Al phosphate is retained, and then reacted with sodium hydroxide in alkaline leaching tank 6 to generate soluble phosphate. The principle is as follows: AlPO4 + 4OH - →[Al(OH)4] - +PO4 3- Al(H2PO4)3 + 10OH - →[Al(OH)4] - +PO4 3- +6H2O The phosphate content in the alkaline leaching solution is detected and metered and transported to reaction tank 11. Based on the phosphate content, the amount of calcium chloride to be added (with a slight excess of calcium ions) is measured. Then, in reaction tank 11, under strongly alkaline conditions, phosphate ions react with calcium ions to form calcium phosphate precipitate. The principle behind the obtained calcium phosphate precipitate is as follows: Ca 2+ +PO4 3- →Ca3(PO4)2↓ After drying and pulverizing, the obtained calcium phosphate product can be obtained. According to the test, the purity of the calcium phosphate product of this utility model can reach more than 80% (calculated as phosphorus), realizing the recycling of phosphorus resources. It should be noted that the equipment used in this utility model is mature and commonly used equipment in industry. This utility model does not make any improvements to the equipment itself. In addition, in this utility model, all tanks, agitators, pumps, centrifuges, conveying pipelines, etc. are made of acid or alkali corrosion resistant materials.

Claims

1. A system for the resource utilization of phosphorus in sludge gasification residue, characterized in that: The system includes an acid leaching tank (4), the front end of which is connected to a silo (2) and a waste acid storage tank (3), the rear end of which is connected to a first centrifuge (5), the acid leaching residue separated by the first centrifuge (5) is transported to the alkaline leaching tank (6) at the rear end, the rear end of the alkaline leaching tank (6) is connected to a second centrifuge (7), the alkaline leaching liquid separated by the second centrifuge (7) is transported to the alkaline leaching liquid storage tank (8) at the rear end, the rear end of the alkaline leaching liquid storage tank (8) is connected to a reaction tank (11), the front end of the reaction tank (11) is also connected to a calcium chloride storage tank (10) and a sodium hydroxide storage tank (9), and the rear end of the reaction tank (11) is connected to a third centrifuge (12).

2. The phosphorus resource utilization system for sludge gasification residue according to claim 1, characterized in that: The silo (2) is equipped with a crusher (1) at the front end, and the crushed material of the sludge gasification residue after being crushed by the crusher (1) is stored in the silo (2).

3. The phosphorus resource utilization system for sludge gasification residue according to claim 1, characterized in that: Each of the acid leaching tank (4), alkali leaching tank (6), and reaction tank (11) is equipped with a stirrer.

4. The phosphorus resource utilization system for sludge gasification residue according to claim 1, characterized in that: The sodium hydroxide storage tank (9) is connected to the alkali leaching tank (6).

5. The phosphorus resource utilization system for sludge gasification residue according to claim 1, characterized in that: The rear end of the third centrifuge (12) is provided with a drying device (13) and a pulverizer (14).

6. The phosphorus resource utilization system for sludge gasification residue according to claim 1, characterized in that: The silo (2) and the acid leaching tank (4) are connected by a screw conveyor, and a control valve and a metering pump are installed on the connecting pipe between the waste acid storage tank (3) and the acid leaching tank (4).

7. A phosphorus resource utilization system for sludge gasification residue according to claim 4, characterized in that: The rear end of the first centrifuge (5) is connected to the alkali leaching tank (6) via a screw conveyor. A control valve and a metering pump are installed on the connecting pipe between the sodium hydroxide storage tank (9) and the alkali leaching tank (6).

8. The phosphorus resource utilization system for sludge gasification residue according to claim 1, characterized in that: A control valve and a metering pump are installed on the connecting pipe between the alkali leaching solution storage tank (8) and the reaction tank (11); a control valve and a metering pump are installed on the connecting pipe between the calcium chloride storage tank (10) and the reaction tank (11); a control valve and a delivery pump are installed on the connecting pipe between the sodium hydroxide storage tank (9) and the reaction tank (11); an online pH meter is installed in the reaction tank (11), and the online pH meter is linked to the delivery pump.

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