System for recovering phosphorus from biogas slurry
Patent Information
- Application Number
- CN202521655538.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-05
- Publication Date
- 2026-10-27
- Estimated Expiration
- 2035-08-05
AI Technical Summary
沼液富含丰富的磷养分，可作为磷回收的重要来源，但沼液中可直接回收的溶解态磷非常少，大量磷素存在于颗粒物中，不仅影响了磷回收效率，也降低了磷肥回收产品质量纯度
[0010]根据本实用新型实施例的回收沼液中磷的系统，包括预处理装置、CIP在线酸化装置、磷检测分析单元、酸化剂添加装置和吸附单元，将沼液供给至预处理装置中，沼液中的大颗粒悬浮物被拦截，得到的预处理后液供给至CIP在线酸化装置与酸化剂混合且维持酸化装置中pH为6-7，可以明显提高沼液中颗粒态磷向溶解性正磷酸盐(Ortho-P)转化，并且酸化处理使Ortho-P含量提高了4～20倍，同时酸化处理可改善随着贮存时间延长而导致Ortho-P减少的现象，同时磷检测分析单元实时检测CIP在线酸化装置中酸化后液中溶解性正磷酸盐浓度，并基于溶解性正磷酸盐浓度的反馈数据控制酸化剂添加装置泵入CIP在线酸化装置中酸化剂的添加量，从而可以保证CIP在线酸化装置中颗粒态磷向溶解性正磷酸盐(Ortho-P)转化，然后将含有磷酸盐的酸化后液供给至吸附单元中进行吸附处理，吸附单元中的复合填料可以吸附酸化后液中的磷酸盐，并且复合填料对沼液磷的回收量达到40.32～150.99mg/g，对磷回收率达到64.10％～99.17％，磷回收效率明显提高。另外复合填料可以将酸化后液中的磷酸盐转化为磷酸镁和磷酸镧，即所得磷回收产物为单一的磷酸盐络合物，磷回收产品纯度明显提高，回收产品磷纯度达到20％～30％，具有显著的经济效益。
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Figure CN224901042U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of agricultural engineering, and specifically relates to a system for recovering phosphorus from biogas slurry. Background Technology
[0002] Phosphorus is a non-renewable strategic resource and a crucial foundation for ensuring my country's food security and the development of high technology. Biogas slurry is rich in phosphorus nutrients and can serve as an important source for phosphorus recovery. However, very little dissolved phosphorus can be directly recovered from biogas slurry; a large amount of phosphorus exists in particulate matter, which not only affects phosphorus recovery efficiency but also reduces the quality and purity of recovered phosphate fertilizer products. To improve phosphorus nutrient recovery from biogas slurry, the first requirement is to reduce the concentration of suspended solids and large molecular organic matter in the biogas slurry to increase phosphorus recovery efficiency; the second requirement is to promote the conversion of various forms of phosphorus into soluble orthophosphate to improve the quality and purity of recovered phosphate fertilizer products.
[0003] Biogas slurry contains a large amount of phosphorus, and total phosphorus (TP) includes solid phosphorus (TP). S ) and liquid phosphorus (TP) L ), TP S and TP L Phosphorus constitutes 49% and 51% of total phosphorus (TP), respectively, with similar proportions in the solid and liquid phases. In the solid phase, it mainly includes iron-aluminum bound phosphorus (Fe / Al-P), calcium-magnesium bound phosphorus (Ca / Mg-P), residual phosphorus (Re-P), and water-soluble phosphorus (H₂O-P). In the liquid phase, it mainly includes dissolved total phosphorus (TDP) and particulate phosphorus (PP), with TDP including dissolved orthophosphate (Ortho-P) and dissolved reduced phosphorus (RDP). Studies have shown that the main form of phosphorus easily recovered by adsorbent materials is Ortho-P, but the Ortho-P content in biogas slurry is less than 30% of total TP. Therefore, increasing the Ortho-P content in biogas slurry and promoting the conversion of other phosphorus forms to Ortho-P is crucial for improving the phosphorus recovery efficiency of biogas slurry. Utility Model Content
[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a system for recovering phosphorus from biogas slurry. This system enables efficient recovery of phosphorus nutrients from biogas slurry, and the recovered phosphorus product is a single phosphate complex, thus improving the quality of fertilizer products.
[0005] This invention proposes a system for recovering phosphorus from biogas slurry. According to an embodiment of this invention, the system includes:
[0006] The pretreatment device includes a filter assembly, a biogas slurry inlet, and a pretreated liquid outlet;
[0007] The CIP online acidification device has a pretreated liquid inlet, an acidifying agent inlet, and an acidified liquid outlet, wherein the pretreated liquid inlet is connected to the pretreated liquid outlet;
[0008] A phosphorus detection and analysis unit is connected to the CIP online acidification device and the acidifier addition device. The acidifier addition device is connected to the acidifier inlet. The phosphorus detection and analysis unit is configured to detect the concentration of soluble orthophosphate in the acidified liquid of the CIP online acidification device, and control the amount of acidifier added by the acidifier addition device into the CIP online acidification device based on the feedback data of the soluble orthophosphate concentration.
[0009] An adsorption unit is provided, comprising a composite packing material, an acidified liquid inlet, and an adsorbed liquid outlet. The acidified liquid inlet is connected to the acidified liquid outlet, and the adsorbed liquid outlet is connected to the CIP online acidification device. The composite packing material comprises a straw-carbon-magnesium-lanthanum-hydrotalcite composite material.
[0010] The system for recovering phosphorus from biogas slurry according to an embodiment of this utility model includes a pretreatment device, a CIP online acidification device, a phosphorus detection and analysis unit, an acidifying agent addition device, and an adsorption unit. Biogas slurry is supplied to the pretreatment device, where large suspended particles are intercepted. The resulting pretreated liquid is then supplied to the CIP online acidification device and mixed with the acidifying agent, maintaining the pH in the acidification device at 6-7. This significantly improves the conversion of particulate phosphorus in the biogas slurry to soluble orthophosphate (Ortho-P), and the acidification treatment increases the Ortho-P content by 4 to 20 times. Simultaneously, the acidification treatment can mitigate the decrease in Ortho-P caused by prolonged storage. The phosphorus detection and analysis unit... The concentration of soluble orthophosphate in the acidified liquid of the CIP online acidification unit is monitored in real time. Based on the feedback data of the soluble orthophosphate concentration, the amount of acidifying agent pumped into the CIP online acidification unit is controlled. This ensures that particulate phosphorus is converted into soluble orthophosphate (Ortho-P) in the CIP online acidification unit. The acidified liquid containing phosphate is then supplied to the adsorption unit for adsorption treatment. The composite packing in the adsorption unit can adsorb the phosphate in the acidified liquid, and the phosphorus recovery of the biogas slurry by the composite packing reaches 40.32-150.99 mg / g, and the phosphorus recovery rate reaches 64.10%-99.17%, which significantly improves the phosphorus recovery efficiency. In addition, the composite packing can convert the phosphate in the acidified liquid into magnesium phosphate and lanthanum phosphate, that is, the obtained phosphorus recovery product is a single phosphate complex. The purity of the phosphorus recovery product is significantly improved, reaching 20%-30%, which has significant economic benefits.
[0011] In addition, the system for recovering phosphorus from biogas slurry according to the above embodiments of this utility model may also have the following additional technical features:
[0012] Furthermore, the filter assembly has a filter screen aperture of 0.75mm-2mm. This effectively intercepts large suspended particles and impurities in the biogas slurry.
[0013] Furthermore, the inner surface of the acidification device is provided with an acid-resistant film. This improves the corrosion resistance of the acidification device.
[0014] Furthermore, the adsorption unit includes an adsorption device, which comprises: an adsorption column, which, from bottom to top, includes an inlet zone, a filtration zone, a lower sieve plate zone, a packing zone, an upper sieve plate zone, and an outlet zone; the acidified liquid inlet is located in the inlet zone; the filtration zone is provided with a stone filter layer; the packing zone is provided with the composite packing material; and the adsorbed liquid outlet is located in the outlet zone; an upper cover; the upper cover is detachably located at the upper end of the outlet zone and has a first sieve hole; and a lower cover; the lower cover is detachably located between the filtration zone and the lower sieve plate zone and has a second sieve hole. This improves the efficiency and quality of phosphorus recovery from the acidified liquid.
[0015] Furthermore, the height of the filtration zone is 3-6 cm; the height of the packing zone is 20-150 cm. This improves the high-quality recovery of phosphorus from the acidified solution.
[0016] Furthermore, the upper sieve plate area has a sieve plate aperture of 0.2-0.4 mm; the lower sieve plate area has a sieve plate aperture of 0.2-0.4 mm; the first sieve aperture has a aperture of 0.4-0.75 mm; and the second sieve aperture has a aperture of 0.4-0.75 mm. This improves the high-quality recovery of phosphorus from the acidified solution.
[0017] Furthermore, the adsorption unit includes multiple adsorption devices connected in series. This improves the high-quality recovery of phosphorus from the acidified solution.
[0018] Furthermore, phosphorus concentration detection components are independently provided at the acidified liquid outlet and the adsorbed liquid outlet, respectively.
[0019] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0020] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0021] Figure 1 This is a schematic diagram of a system structure for recovering phosphorus from biogas slurry according to an embodiment of the present invention;
[0022] Figure 2 This is a schematic diagram of the adsorption device in a system for recovering phosphorus from biogas slurry according to another embodiment of the present invention. Detailed Implementation
[0023] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.
[0024] This application proposes a system for recovering phosphorus from biogas slurry. According to embodiments of this invention, refer to... Figure 1 The system includes: a pretreatment device 100, a CIP online acidification device 200, a phosphorus detection and analysis unit 300, an acidifying agent addition device 400, and an adsorption unit 500.
[0025] According to an embodiment of the present invention, the pretreatment device 100 has a filter assembly 10, a biogas slurry inlet 101 and a pretreated liquid outlet 102, and is suitable for filtering biogas slurry to obtain large particulate suspended matter and pretreated liquid, and temporarily storing the pretreated liquid in a temporary storage tank 11.
[0026] Furthermore, the filter assembly 10 has a filter screen with a mesh size of 0.75mm-2mm, which can effectively remove large suspended particles from the biogas slurry. The effective filtration area of the filter screen is 3-4 times the flow area of the inlet pipe. It is also equipped with an anti-clogging sludge pump with a power of 4kW and a separation capacity of 8-15m³. 3 / h, suitable for biogas slurry with a solid content of 1%-8%.
[0027] According to an embodiment of this utility model, the CIP online acidification device 200 has a pretreated liquid inlet 201, an acidifying agent inlet 202, and an acidified liquid outlet 203. The pretreated liquid inlet 201 is connected to the pretreated liquid outlet 202 and is suitable for mixing the pretreated liquid and the acidifying agent while maintaining the pH of the system at 6-7 to obtain an acidified liquid containing phosphate. This significantly improves the conversion of particulate phosphorus to soluble orthophosphate (Ortho-P) in biogas slurry, and the acidification treatment increases the Ortho-P content by 4 to 20 times. Simultaneously, the acidification treatment can mitigate the phenomenon of Ortho-P reduction with prolonged storage time.
[0028] Furthermore, to prevent the acidification device 200 from being corroded, an acid-resistant film can be provided on the inner surface of the acidification device 200, thereby improving the acid resistance of the acidification device 200.
[0029] Furthermore, the acidifying agent includes at least one of sulfuric acid, citric acid, and tartaric acid, preferably sulfuric acid.
[0030] It should be noted that those skilled in the art can select the material of the acid-resistant membrane according to actual needs, as long as it has acid resistance, which will not be elaborated here.
[0031] According to an embodiment of this utility model, the phosphorus detection and analysis unit 300 is connected to the CIP online acidification device 200 and the acidifier addition device 400. The acidifier addition device 400 is connected to the acidifier inlet 202. The phosphorus detection and analysis unit 300 is configured to detect the concentration of soluble orthophosphate in the acidified liquid of the CIP online acidification device 200, and control the amount of acidifier added by the acidifier addition device 400 into the CIP online acidification device 200 based on the feedback data of the soluble orthophosphate concentration, thereby ensuring the conversion of particulate phosphorus to soluble orthophosphate (Ortho-P) in the CIP online acidification device 200. Specifically, when the phosphorus detection and analysis unit 300 detects that the concentration of soluble orthophosphate in the acidified solution is higher than 150 mg / L, it controls the acidifier addition device 400 to reduce the amount of acidifier added to the CIP online acidification device 200; when the phosphorus detection and analysis unit 300 detects that the concentration of soluble orthophosphate in the acidified solution is lower than 150 mg / L, it controls the acidifier addition device 400 to increase the amount of acidifier added to the CIP online acidification device 200.
[0032] It should be noted that the phosphorus detection and analysis unit 300 is a conventional device used in the field that can detect the concentration of soluble orthophosphate, and will not be described in detail here.
[0033] According to an embodiment of this utility model, the adsorption unit 500 has a composite packing 51, an acidified liquid inlet 501, and an adsorbed liquid outlet 502. The acidified liquid inlet 501 is connected to the acidified liquid outlet 203, and the adsorbed liquid outlet 502 is connected to the CIP online acidification device 200. The composite packing 51 comprises a straw-based magnesium-lanthanum-hydrotalcite composite material and is suitable for adsorbing the acidified liquid containing phosphate to obtain a compound fertilizer containing magnesium phosphate and lanthanum phosphate and an adsorbed liquid. The adsorbed liquid is then returned to the CIP online acidification device 200. Thus, the composite packing 51 in the adsorption unit 500 can adsorb phosphate in the acidified liquid, and the composite packing achieves a phosphorus recovery rate of 40.32–150.99 mg / g from the biogas slurry, with a phosphorus recovery rate of 64.10%–99.17%, significantly improving phosphorus recovery efficiency. In addition, the composite packing can convert the phosphate in the acidified solution into magnesium phosphate and lanthanum phosphate, that is, the obtained phosphorus recovery product is a single phosphate complex, the purity of the phosphorus recovery product is significantly improved, the phosphorus purity of the recovered product reaches 20% to 30%, which has significant economic benefits.
[0034] It should be noted that the "straw-char magnesium lanthanum hydrotalcite composite material" in this application refers to the Mg / La material in the 2023 doctoral dissertation of Huazhong Agricultural University entitled "Research on the Mechanism and Process of Phosphorus Recovery from Biogas Slurry by Straw Char-Reinforced Magnesium Lanthanum Hydrotalcite (LDH)". 0.1 -LDO (molar ratio n(Mg)) 2+ ) / n(La 3+ The ratio is 10 / 1), and its preparation method is as described in Chapter 3, Section 3.1.1, Material Processing and Preparation.
[0035] For details, please refer to Figure 1 After acidification is completed, the control valve 203 at the outlet 202 of the acidified liquid uses the transfer pump 204 to slowly supply the acidified liquid to the adsorption unit 500 at a set flow rate.
[0036] According to one embodiment of the present invention, reference is made to... Figure 2 The adsorption unit 500 includes an adsorption device 50, and the adsorption device 350 includes an adsorption column 52, an upper cover 53, and a lower cover 54.
[0037] refer to Figure 2The adsorption column 52 includes, from bottom to top, an inlet zone 521, a filtration zone 522, a lower sieve plate zone 523, a packing zone 524, an upper sieve plate zone 525, and an outlet zone 526. The acidified liquid inlet 501 is located in the inlet zone 521. The filtration zone 522 is provided with a stone filter layer. The packing zone 524 is provided with the composite packing 51. The adsorbed liquid outlet 502 is located in the outlet zone 526. The upper cover 53 is detachably located at the upper end of the outlet zone 526 and is provided with a first sieve hole 531. The lower cover 54 is detachably located between the filtration zone 522 and the lower sieve plate zone 523 and is provided with a second sieve hole 541. Specifically, the acidified liquid enters the feed zone 521 from the acidified liquid inlet 501, then passes through the stone filter layer in the filtration zone 522, then through the sieve plate on the lower cover 53, and then through the sieve plate in the lower sieve plate zone 523. After that, it is fully adsorbed by the composite packing in the packing zone 524, which can adsorb the phosphate in the acidified liquid. The adsorbed liquid passes through the sieve plate in the upper sieve plate zone 525, and then enters the liquid outlet zone 526. It is then discharged from the adsorption device 50 through the sieve plate on the upper cover 53 and the adsorbed liquid outlet 502 in sequence.
[0038] Specifically, the aforementioned adsorption column 52 is a cylinder with a diameter of 15–35 cm and a height of 160–200 cm. To improve phosphorus recovery, multiple adsorption devices 50 can be connected in series, for example, 1–3 devices. The height of the composite packing can be 20–150 cm. The sieve plates in the upper cover 53 and lower cover 54 have a pore size of 0.4–0.75 mm and a thickness of 1.5–2.5 cm. The stone filter layer has a height of 3–6 cm, and the lower cover… The edges of 54 or the upper cover 53 are sealed with silicone sealing rings to prevent biogas slurry from seeping in. Meanwhile, the sieve plate in the lower sieve plate area 523 has a sieve plate with a hole diameter of 0.2-0.4 mm and a sieve plate thickness of 1.0-1.5 cm, and the sieve plate in the upper sieve plate area 525 has a sieve plate with a hole diameter of 0.2-0.4 mm and a sieve plate thickness of 1.0-1.5 cm. Furthermore, a transfer pump with a power of 4-5 kW is provided at the acidified liquid inlet 501 of the adsorption device 50.
[0039] According to an embodiment of this utility model, phosphorus concentration detection components are independently provided at the acidification liquid inlet 301 and the adsorption liquid outlet 302. Specifically, the adsorption device 30 processes 0.1 to 0.5 m³ of... 3 When processing biogas slurry, the phosphorus concentration is read from the phosphorus concentration detection components at the acidified liquid inlet 301 and the adsorbed liquid outlet 302 until the phosphorus concentration in the adsorbed liquid (C) is reached. t The concentration (C0) of the influent to the acidified solution at inlet 301 is close to that of the acidified solution, and when C tWhen C0 = 0.90, the system stops operating, indicating that the composite packing material in adsorption device 30 is saturated. The contents can then be removed by opening the upper cover 33 or the lower cover 34, dried, and then sealed for storage. However, if C... t When C0 = 0.85-0.90, the adsorbed liquid is returned to acidification unit 200, while when C... t When C0 = 0.1-0.15, the adsorbed liquid can be directly discharged into the advanced treatment tank. Furthermore, to recover the composite packing material, a sodium carbonate solution can be used to decompose it.
[0040] The system for recovering phosphorus from biogas slurry according to an embodiment of this utility model includes a pretreatment device, a CIP online acidification device, a phosphorus detection and analysis unit, an acidifying agent addition device, and an adsorption unit. Biogas slurry is supplied to the pretreatment device, where large suspended particles are intercepted. The resulting pretreated liquid is then supplied to the CIP online acidification device and mixed with the acidifying agent, maintaining the pH in the acidification device at 6-7. This significantly improves the conversion of particulate phosphorus in the biogas slurry to soluble orthophosphate (Ortho-P), and the acidification treatment increases the Ortho-P content by 4 to 20 times. Simultaneously, the acidification treatment can mitigate the decrease in Ortho-P caused by prolonged storage. The phosphorus detection and analysis unit... The concentration of soluble orthophosphate in the acidified liquid of the CIP online acidification unit is monitored in real time. Based on the feedback data of the soluble orthophosphate concentration, the amount of acidifying agent pumped into the CIP online acidification unit is controlled. This ensures that particulate phosphorus is converted into soluble orthophosphate (Ortho-P) in the CIP online acidification unit. The acidified liquid containing phosphate is then supplied to the adsorption unit for adsorption treatment. The composite packing in the adsorption unit can adsorb the phosphate in the acidified liquid, and the phosphorus recovery of the biogas slurry by the composite packing reaches 40.32-150.99 mg / g, and the phosphorus recovery rate reaches 64.10%-99.17%, which significantly improves the phosphorus recovery efficiency. In addition, the composite packing can convert the phosphate in the acidified liquid into magnesium phosphate and lanthanum phosphate, that is, the obtained phosphorus recovery product is a single phosphate complex. The purity of the phosphorus recovery product is significantly improved, reaching 20%-30%, which has significant economic benefits.
[0041] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0042] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. A system for recovering phosphorus from biogas slurry, characterized in that, include: The pretreatment device includes a filter assembly, a biogas slurry inlet, and a pretreated liquid outlet; The CIP online acidification device has a pretreated liquid inlet, an acidifying agent inlet, and an acidified liquid outlet, wherein the pretreated liquid inlet is connected to the pretreated liquid outlet; A phosphorus detection and analysis unit is connected to the CIP online acidification device and the acidifier addition device. The acidifier addition device is connected to the acidifier inlet. The phosphorus detection and analysis unit is configured to detect the concentration of soluble orthophosphate in the acidified liquid of the CIP online acidification device, and control the amount of acidifier added by the acidifier addition device into the CIP online acidification device based on the feedback data of the soluble orthophosphate concentration. An adsorption unit is provided, comprising a composite packing material, an acidified liquid inlet, and an adsorbed liquid outlet. The acidified liquid inlet is connected to the acidified liquid outlet, and the adsorbed liquid outlet is connected to the CIP online acidification device. The composite packing material comprises a straw-carbon-magnesium-lanthanum-hydrotalcite composite material.
2. The system according to claim 1, characterized in that, The filter assembly has a filter screen aperture of 0.75mm-2mm.
3. The system according to claim 1, characterized in that, The inner surface of the CIP online acidification device is provided with an acid-resistant film.
4. The system according to any one of claims 1-3, characterized in that, The adsorption unit includes an adsorption device, which includes: An adsorption column, from bottom to top, includes an inlet zone, a filtration zone, a lower sieve plate zone, a packing zone, an upper sieve plate zone, and an outlet zone. The acidified liquid inlet is located in the inlet zone, the filtration zone is provided with a stone filter layer, the packing zone is provided with the composite packing material, and the adsorbed liquid outlet is located in the outlet zone. The upper cover is detachably disposed at the upper end of the liquid outlet area, and the upper cover is provided with a first sieve hole; The lower cover is detachably disposed between the filtration zone and the lower sieve plate zone, and the lower cover is provided with a second sieve hole.
5. The system according to claim 4, characterized in that, The height of the filtration zone is 3-6cm.
6. The system according to claim 4, characterized in that, The height of the filling zone is 20-150cm.
7. The system according to claim 4, characterized in that, The aperture of the sieve plate in the upper sieve plate area is 0.2-0.4 mm; The aperture of the sieve plate in the lower sieve plate area is 0.2-0.4 mm.
8. The system according to claim 4, characterized in that, The aperture of the first sieve is 0.4-0.75 mm; The aperture of the second sieve is 0.4-0.75 mm.
9. The system according to claim 4, characterized in that, The adsorption unit includes multiple adsorption devices connected in series.
10. The system according to claim 4, characterized in that, The acidified liquid inlet and the adsorbed liquid outlet are each equipped with an independent phosphorus concentration detection component.