System for preparing polyaluminum chloride

Abstract

The utility model relates to the technical field of chemical engineering, in particular to a system for preparing polyaluminum chloride. The system comprises: a reaction unit; the solid-liquid separation device is communicated with the reaction unit; the membrane filtration device is communicated with the solid-liquid separation device; and the drying device is communicated with the membrane filtration device. The system integrates a reaction unit, a solid-liquid separation device, a membrane filtration device and a drying device to form a complete polyaluminum chloride preparation process. By arranging the membrane filtration device between the solid-liquid separation device and the drying device, on one hand, the polyaluminum chloride liquid can be effectively concentrated, so that the concentration of the polyaluminum chloride liquid is improved, and the energy consumption required in the drying process is correspondingly reduced; and on the other hand, the membrane filtration device can ensure that the concentration of the polyaluminum chloride liquid entering the drying device is stable, so that the product quality is improved and the energy consumption is reduced.

Description

Technical Field

[0001] This application relates to the field of chemical technology, and in particular to a system for preparing polyaluminum chloride. Background Technology

[0002] Polyaluminum chloride (PAC) is a novel, highly efficient inorganic polymeric flocculant with excellent coagulation and sedimentation properties. It is primarily used in water treatment, food additives, and papermaking industries. The PAC industry is resource-intensive, energy-intensive, and has low added value; its energy consumption mainly consists of heat and electricity.

[0003] Natural gas, as the primary energy source, provides heat for the production of polyaluminum chloride (PAC) through combustion, drying liquid PAC into solid PAC. Natural gas has become a significant factor in the production cost and environmental impact of PAC. Furthermore, the alumina content of the liquid PAC plays a decisive role in the natural gas consumption during the drying process. Currently, Chinese companies mainly use spray drying equipment to dry PAC, with two spray methods: centrifugal and pressure. However, research on energy conservation and consumption reduction in the centrifugal atomization drying method for PAC is relatively limited. Utility Model Content

[0004] This application provides a system for preparing polyaluminum chloride to solve the technical problem of how to reduce energy consumption during the drying process of polyaluminum chloride.

[0005] This application provides a system for preparing polyaluminum chloride, the system comprising:

[0006] A reaction unit is used to react and generate polyaluminum chloride, resulting in a mixed slurry containing the polyaluminum chloride;

[0007] A solid-liquid separation device is used to separate the mixed slurry into solid and liquid components to obtain polyaluminum chloride liquid and filter residue. The solid-liquid separation device is connected to the reaction unit.

[0008] A membrane filtration device is used to concentrate the polyaluminum chloride liquid to a set concentration, and the membrane filtration device is connected to the solid-liquid separation device;

[0009] A drying device is used to dry the polyaluminum chloride liquid with a set concentration to obtain polyaluminum chloride solid, and the drying device is connected to the membrane filtration device.

[0010] Optionally, the membrane filtration device is equipped with a tubular membrane.

[0011] Optionally, the tubular membrane is made of polyetherketone.

[0012] Optionally, the pore size of the tubular membrane is 10 nm to 500 nm.

[0013] Optionally, the reaction unit includes:

[0014] Ingredient tank;

[0015] An atmospheric pressure reactor, which is connected to the mixing tank.

[0016] Optionally, the mixing tank is equipped with a hydrochloric acid inlet, an aluminum hydroxide inlet, and a calcium aluminate powder inlet.

[0017] Optionally, both the mixing tank and the atmospheric pressure reactor are equipped with a stirring component.

[0018] Optionally, the atmospheric pressure reactor is equipped with a steam heater.

[0019] Optionally, the drying device is a spray drying tower.

[0020] Optionally, the solid-liquid separation device is a filter press.

[0021] The technical solutions provided in this application have the following advantages compared with the prior art:

[0022] This application provides a system for preparing polyaluminum chloride (PAC). The system includes: a reaction unit for reacting to generate PAC, resulting in a mixed slurry containing the PAC; a solid-liquid separation device for separating the mixed slurry into liquid PAC and filter residue, the solid-liquid separation device being connected to the reaction unit; a membrane filtration device for concentrating the liquid PAC to a set concentration, the membrane filtration device being connected to the solid-liquid separation device; and a drying device for drying the liquid PAC at the set concentration to obtain solid PAC, the drying device being connected to the membrane filtration device. This system integrates the reaction unit, solid-liquid separation device, membrane filtration device, and drying device, forming a complete PAC preparation process. This highly integrated system design not only simplifies the operation process but also reduces the transfer and storage time of materials between different devices, thereby reducing the risk of contamination and improving production efficiency. By installing a membrane filtration device between the solid-liquid separation unit and the drying unit, the polyaluminum chloride liquid can be effectively concentrated, thereby increasing its concentration and reducing the energy consumption required during the drying process. On the other hand, the membrane filtration device can also ensure the stability of the concentration of polyaluminum chloride liquid entering the drying unit, which helps to improve product quality and reduce energy consumption. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a system for preparing polyaluminum chloride provided in an embodiment of this application;

[0026] Among them, 1-reaction unit, 11-mixing tank, 12-atmospheric pressure reactor, 2-solid-liquid separation device, 3-membrane filtration device, 4-drying device, 5-liquid storage device. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] It should be noted that all directional indicators such as up, down, left, right, front, back, etc. in the embodiments of this utility model are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the attached figure). If the specific posture changes, the directional indicator will also change accordingly.

[0029] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, or a magnetic connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0030] Figure 1 This is a schematic diagram of a system for preparing polyaluminum chloride provided in an embodiment of this application.

[0031] like Figure 1 As shown in the figure, this application provides a system for preparing polyaluminum chloride, the system comprising:

[0032] Reaction unit 1 is used to react and generate polyaluminum chloride to obtain a mixed slurry containing the polyaluminum chloride;

[0033] Solid-liquid separation device 2 is used to separate the mixed slurry into solid and liquid components to obtain polyaluminum chloride liquid and filter residue. The solid-liquid separation device 2 is connected to the reaction unit 1.

[0034] A membrane filtration device 3 is used to concentrate the polyaluminum chloride liquid to a set concentration, and the membrane filtration device 3 is connected to the solid-liquid separation device 2;

[0035] The drying device 4 is used to dry the polyaluminum chloride liquid with a set concentration to obtain polyaluminum chloride solid. The drying device 4 is connected to the membrane filtration device 3.

[0036] In some embodiments, the membrane filtration device 3 is provided with a tubular membrane.

[0037] In some embodiments, the tubular membrane is made of polyetherketone.

[0038] In some embodiments, the pore size of the tubular membrane is 10 nm to 500 nm.

[0039] Currently, modifying existing polyaluminum chloride (PAC) production processes using new technologies is an effective way to reduce natural gas consumption per unit area. As a highly efficient and energy-saving common separation technology, membrane technology, based on selectively permeable membrane materials, can achieve the separation, purification, and concentration of mixtures. This process is physical, characterized by no phase change, low energy consumption, separability, and high automation. It exhibits excellent separation capabilities for colloids, suspended particles, color, turbidity, bacteria, and large organic molecules. Membrane technology is widely used in environmental protection, pharmaceuticals, dairy products, biochemistry, food and beverage, and chemical industries. However, research on applying membrane technology to PAC production and reducing natural gas consumption per unit area has not yet been reported in this specific field.

[0040] This application introduces a tubular membrane filtration device made of polyetherketone (PEK). PEK material possesses excellent corrosion resistance, high-temperature resistance, and mechanical strength, making it suitable for treating highly corrosive polyaluminum chloride solutions. The tubular membrane filtration device concentrates the filtered polyaluminum chloride liquid, increasing the solution concentration and reducing energy consumption in the subsequent drying process. The drying device and membrane filtration device work closely together to ensure a stable and compliant concentration of the polyaluminum chloride liquid input to the drying device.

[0041] Using tubular nanofiltration membranes with pore sizes ranging from 10 nm to 500 nm offers the following advantages: High-efficiency concentration: Nanofiltration membranes can trap polyaluminum chloride molecules and larger colloidal particles while allowing water to pass through, thus achieving solution concentration. This concentration method is more efficient than traditional evaporation or thermal drying, significantly reducing energy consumption. Improved purity: Nanofiltration can further remove impurities and contaminants from the solution, improving the purity of polyaluminum chloride. This is crucial for producing high-quality, high-value-added polyaluminum chloride products. For example, the pore sizes of the tubular membranes can be 10 nm, 20 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, etc.

[0042] In some embodiments, the reaction unit 1 includes:

[0043] Ingredient tank 11;

[0044] An atmospheric pressure reactor 12 is connected to the mixing tank 11.

[0045] In some embodiments, the mixing tank 11 is provided with a hydrochloric acid inlet, an aluminum hydroxide inlet, and a calcium aluminate powder inlet.

[0046] In some embodiments, both the mixing tank 11 and the atmospheric pressure reactor 12 are equipped with stirring components.

[0047] In some embodiments, the atmospheric pressure reactor 12 is equipped with a steam heater.

[0048] In this embodiment, hydrochloric acid, aluminum hydroxide, and calcium aluminate powder are used as raw materials, and steam is used as a heat source for the reaction in an atmospheric pressure tank.

[0049] In some embodiments, the drying device 4 is a spray drying tower.

[0050] The working principle of a spray drying tower is as follows: air is introduced into the air distributor at the top of the tower after passing through a filter and a heater, and then enters the drying chamber evenly in a spiral pattern. Simultaneously, the liquid feed is pumped from the feed tank through a filter to a centrifugal atomizer at the top of the tower, atomizing it into extremely fine droplets. These droplets come into contact with hot air in parallel flow, causing the moisture to evaporate rapidly, thus drying the product into a finished product in a very short time. The finished product is discharged from the bottom of the drying tower and through a cyclone separator, while the exhaust gas is discharged by a fan.

[0051] In some embodiments, the solid-liquid separation device 2 is a filter press.

[0052] In some embodiments, the system further includes:

[0053] Liquid storage device 5 is disposed between the solid-liquid separation device 2 and the membrane filtration device 3.

[0054] In some embodiments, the liquid storage device 5 is a liquid storage pool or a liquid storage tank.

[0055] In some embodiments, the atmospheric pressure reactor is provided with a filter residue inlet for a pressurized reactor.

[0056] This application provides two processes for producing polyaluminum chloride (PAC): one is a pressurized process, and the other is an atmospheric pressure process. The atmospheric pressure process uses hydrochloric acid, aluminum hydroxide, and calcium aluminate powder as raw materials, with steam as the heat source, and the reaction takes place in an atmospheric pressure tank. After the reaction, the mixture is filtered, and the resulting liquid is liquid PAC. The pressurized process uses hydrochloric acid and aluminum hydroxide as raw materials, with steam as the heat source, and the reaction takes place in a reactor. After the reaction, the mixture is filtered, and the resulting liquid is also liquid PAC. The filter residue contains unreacted aluminum hydroxide, which can be used as part of the raw material for the atmospheric pressure reactor, thus improving resource utilization.

[0057] The system for preparing polyaluminum chloride provided in this application has several significant advantages over traditional production processes, mainly in the following aspects:

[0058] I. High-efficiency concentration and energy saving. (1) Tubular membrane concentration using polyetherketone (PEK) material: Polyetherketone (PEK) material has excellent chemical resistance and heat resistance, and can remain stable in corrosive environments, making it suitable for the concentration of polyaluminum chloride liquid. The tubular membrane structure is conducive to the efficient retention of polyaluminum chloride molecules, while allowing water and other small molecules to pass through, thereby achieving rapid concentration. (2) Reduced natural gas consumption: Concentrating polyaluminum chloride liquid through a membrane filtration device reduces the moisture content in the subsequent drying process, thereby reducing the energy consumption required for drying, especially the consumption of natural gas.

[0059] II. Process Optimization and Quality Improvement. (1) System Continuity: The reaction unit, filtration device, membrane filtration device, and drying device are closely connected to form a complete production process, which is conducive to achieving automated control and continuous production. This continuity reduces the transfer and storage time of materials between various links, reduces the risk of contamination, and improves product quality. (2) Quality Control: The system can be equipped with advanced testing equipment and methods to monitor and analyze polyaluminum chloride liquid in real time, ensuring that the product quality meets the standards. By optimizing the production process and parameter control, the purity and stability of the product can be further improved.

[0060] III. Environmental Protection and Sustainable Development. (1) Reduced Wastewater Discharge: Membrane filtration devices can retain most harmful substances and impurities during the concentration process, reducing the pollutant content in wastewater. This helps reduce wastewater treatment costs and environmental pollution. (2) Resource Recycling: Waste such as filter residue generated in the system can be further processed and utilized, such as for the production of other chemicals or as building materials. This helps achieve the goals of resource recycling and energy conservation and emission reduction. (3) Green Production: The entire system adopts advanced production processes and equipment, which helps reduce energy consumption and emissions. Through continuous improvement and optimization of production processes, the environmental performance and sustainability of the system can be further improved.

[0061] In summary, the system for preparing polyaluminum chloride provided in this application has significant advantages in terms of high-efficiency concentration and energy saving, process optimization and quality improvement, as well as environmental protection and sustainable development. These advantages not only improve production efficiency and product quality, but also help reduce production costs and environmental impact, thus possessing significant application value and social benefits.

[0062] The embodiments of this application are further illustrated below with reference to specific examples. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards; if there is no corresponding industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0063] Example 1

[0064] like Figure 1 As shown in the figure, this application provides a system for preparing polyaluminum chloride, the system comprising:

[0065] A reaction unit is used to react and generate polyaluminum chloride, obtaining a mixed slurry containing the polyaluminum chloride. The reaction unit includes: a mixing tank; and an atmospheric pressure reactor connected to the mixing tank. The mixing tank is equipped with a hydrochloric acid inlet, an aluminum hydroxide inlet, and a calcium aluminate powder inlet. Both the mixing tank and the atmospheric pressure reactor are equipped with stirring components. The atmospheric pressure reactor is equipped with a steam heater. Hydrochloric acid, aluminum hydroxide, and calcium aluminate powder are used as raw materials, and steam is used as a heat source in the atmospheric pressure reactor for the reaction.

[0066] A solid-liquid separation device is provided, which is connected to the reaction unit; the solid-liquid separation device is a filter press. After the reaction is completed, the mixture is filtered, and the resulting liquid is polyaluminum chloride liquid with an aluminum content of 13.5%.

[0067] A liquid storage device, which is a liquid storage tank, has its inlet connected to a solid-liquid separation device.

[0068] A membrane filtration device is provided, which is connected to the liquid storage device; the membrane filtration device is equipped with a tubular membrane. The tubular membrane is made of polyetherketone (PEK) and has a pore size of 100 nm. Liquid polyaluminum chloride is concentrated using a polyetherketone (PEK) tubular membrane, and the resulting liquid polyaluminum chloride has an aluminum content of 17.5%.

[0069] The spray drying tower is connected to the membrane filtration device. Liquid polyaluminum chloride enters the spray drying tower (using centrifugal atomization principle), where it is dried by a heat source provided by natural gas combustion to obtain solid polyaluminum chloride with an aluminum content of 29.5%.

[0070] The application of membrane technology can reduce the natural gas consumption per unit of polyaluminum chloride by 33.95 m³. 3 This increases electricity consumption by 55.45 kWh / t, but reduces overall energy consumption by 19.877 tons of standard coal equivalent per ton of product. Membrane technology is suitable for the polyaluminum chloride (PAC) industry and should be vigorously promoted and used to drive energy conservation and emission reduction in PAC production. It also serves as a model for cost reduction and energy conservation throughout the entire PAC industry chain.

[0071] The polyaluminum chloride (PAC) industry is an energy-intensive industry, making research on energy conservation and consumption reduction essential. This application utilizes the characteristics of membrane technology and applies a tubular membrane made of polyetherketone (PEK) to PAC production to reduce natural gas consumption per unit. The main focus is on exploring the applicability of membrane technology in the PAC production process, its role in reducing natural gas consumption per unit, and its energy-saving and cost-reducing effects. Experimental results show that membrane technology is suitable for PAC production, reducing natural gas consumption by 33.95 m³ / s. 3 / t, and the application of membrane technology can significantly reduce the production cost of polyaluminum chloride.

[0072] The above descriptions are merely specific implementations of the embodiments of this application, enabling those skilled in the art to understand or implement the embodiments of this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined in the embodiments of this application can be implemented in other embodiments without departing from the spirit or scope of the embodiments of this application. Therefore, the embodiments of this application are not limited to the embodiments shown in this application, but are to be accorded the widest scope consistent with the principles and novel features claimed in the embodiments of this application.

Claims

1. A system for preparing polyaluminum chloride, characterized in that, The system includes: The reaction unit (1) is used to react and generate polyaluminum chloride to obtain a mixed slurry containing the polyaluminum chloride; A solid-liquid separation device (2) is used to separate the mixed slurry into solid and liquid components to obtain polyaluminum chloride liquid and filter residue. The solid-liquid separation device (2) is connected to the reaction unit (1). A membrane filtration device (3) is used to concentrate the polyaluminum chloride liquid to a set concentration, and the membrane filtration device (3) is connected to the solid-liquid separation device (2); A drying device (4) is used to dry the polyaluminum chloride liquid with a set concentration to obtain polyaluminum chloride solid. The drying device (4) is connected to the membrane filtration device (3).

2. The system according to claim 1, characterized in that, The membrane filtration device (3) is equipped with a tubular membrane.

3. The system according to claim 2, characterized in that, The tubular membrane is made of polyetherketone.

4. The system according to claim 3, characterized in that, The tubular membrane has a pore size of 10 nm to 500 nm.

5. The system according to claim 1, characterized in that, The reaction unit (1) includes: Ingredient tank (11); An atmospheric pressure reactor (12) is connected to the mixing tank (11).

6. The system according to claim 5, characterized in that, The mixing tank (11) is equipped with a hydrochloric acid inlet, an aluminum hydroxide inlet, and a calcium aluminate powder inlet.

7. The system according to claim 5, characterized in that, Both the mixing tank (11) and the atmospheric pressure reactor (12) are equipped with stirring components.

8. The system according to claim 5, characterized in that, The atmospheric pressure reactor (12) is equipped with a steam heater.

9. The system according to claim 1, characterized in that, The drying device (4) is a spray drying tower.

10. The system according to claim 1, characterized in that, The solid-liquid separation device (2) is a filter press.

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