Precise adding device for municipal sludge chemical modification agent

Abstract

The utility model relates to an accurate adding device for a municipal sludge chemical modification agent, which is characterized in that a sludge flow meter and a first modifier flow meter are respectively arranged at a sludge inlet and a modifier inlet of a stirring tank, and a water content detection system is used for actually measuring the water content of sludge flowing into the sludge flow meter; an inlet of the first modifier flow meter is communicated with an outlet of the first dosing pump, an inlet of the first dosing pump is communicated with an outlet of the first modifier storage tank, and the sludge flow meter, the first modifier flow meter, the moisture content detection system and the first dosing pump are electrically connected with the control system respectively. The method has the beneficial effects that the modifier is added in a targeted manner based on the real-time water content and flow of the sludge, so that the problems of inaccurate and insufficient chemical modification of the sludge under the condition of large sludge property change coefficient caused by irregular sewage quantity and sludge proportion are effectively solved, the adding precision of the modifier is improved, the sufficient modification of the sludge is realized, and the service life of the sludge is prolonged. The sludge dewatering performance is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of environmental protection, in particular to a device for accurately dosing a municipal sludge chemical modification agent. Background Art

[0002] With the acceleration of urbanization, the demand for urban sewage treatment is increasing dramatically. Municipal sludge dewatering is one of the key processes for sewage treatment in municipal sewage treatment plants. Municipal sludge dewatering usually uses processes such as mechanical dewatering and drying to reduce the sludge volume, thereby achieving sludge reduction and harmlessness. In the municipal sludge dewatering process, the effect of chemical modification directly affects the sludge dewatering efficiency and quality. The traditional sludge dewatering process adopts the method of chemical modification of sludge by adding a quantitative modifier in proportion to the real-time flow rate of sludge, assuming that the initial moisture content of the sludge is constant. When the sludge properties and the ratio of primary sedimentation tank sludge to residual sludge are relatively stable, the initial moisture content of the sludge is basically stable within a small range. This modification method can achieve stable modification of the sludge to achieve better dewatering effect. However, during the rainy season, irregular sewage discharge, and when the coefficient of variation of the ratio of primary sedimentation tank sludge to residual sludge is large, the initial moisture content of the sludge is unstable. Traditional moisture content testing methods are usually time-consuming and have limited accuracy. Using the above method will not achieve targeted modification effects, which will directly affect the subsequent dehydration or drying treatment process.

[0003] Therefore, exploring a precise dosing device for municipal sludge chemical modification agents that can effectively cope with situations where sludge properties change greatly has become an urgent problem to be solved in the municipal sludge dewatering industry. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a device for accurately dosing a municipal sludge chemical modification agent, so as to overcome the deficiencies in the above-mentioned prior art.

[0005] The technical solution of the utility model to solve the above-mentioned technical problems is as follows: A precise dosing device for chemical modifiers of municipal sludge, comprising: a stirring tank and a moisture content detection system, the sludge inlet and the modifier inlet of the stirring tank are respectively provided with a sludge flowmeter and a first modifier flowmeter, the moisture content detection system is used to measure the moisture content of the sludge flowing into the sludge flowmeter, the inlet of the first modifier flowmeter is connected to the outlet of the first dosing pump, the inlet of the first dosing pump is connected to the outlet of the first modifier storage tank, the sludge flowmeter, the first modifier flowmeter, the moisture content detection system and the first dosing pump are respectively electrically connected to the control system.

[0006] On the basis of the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the moisture content detection system includes: a microwave transmitter and a signal processing system. The microwave transmitter is used to generate a microwave signal of a certain frequency, which is irradiated on the sludge surface and passes through the sludge. The signal generates energy loss through reflection and transmission in the sludge medium and is collected. The microwave transmitter transmits the collected reflection and transmission signals to the signal processing system, and the signal processing system is electrically connected to the control system.

[0008] Furthermore, the discharge port of the stirring tank is connected to the inlet of the concentration tank.

[0009] Furthermore, the discharge port of the concentration tank is communicated with the inlet of the sludge dewatering treatment equipment, and the sludge dewatering treatment equipment is electrically connected to the control system.

[0010] Furthermore, the sludge dewatering treatment equipment includes: a feed pump and a second dosing pump, the discharge port of the thickening tank is connected to the inlet of the feed pump, the outlet of the feed pump is connected to the inlet of the plate and frame filter press via a modified concentrated sludge flowmeter, the inlet of the second dosing pump is connected to the outlet of the second modifier storage tank, the outlet of the second dosing pump is connected to the inlet of the plate and frame filter press via a second modifier flowmeter, and the modified concentrated sludge flowmeter, the second dosing pump and the second modifier flowmeter are electrically connected to the control system respectively.

[0011] Furthermore, the first modifier storage tank stores PAC, and the second modifier storage tank stores PAM.

[0012] Furthermore, the control system is electrically connected to the alarm system. A liquid level lower limit sensor is provided in the first modifier storage tank, and the liquid level lower limit sensor is electrically connected to the control system.

[0013] Furthermore, the alarm system adopts an audible and visual alarm system.

[0014] Furthermore, the control system adopts a PLC control system.

[0015] The beneficial effects of the utility model are:

[0016] 1) Based on the real-time moisture content and flow rate of the sludge, targeted addition of modifiers can effectively solve the problems of inaccurate and insufficient sludge chemical modification when the sludge property variation coefficient is large due to irregular sewage volume and sludge ratio;

[0017] 2) Set the absolute dry sludge dosage ratio, calculate the theoretical dosage and use flow tracking to adjust the dosing pump frequency, improve the dosing accuracy of the modifier, achieve full modification of the sludge, significantly improve the sludge dewatering performance, ensure the subsequent sludge solidification efficiency, reduce production time cost and energy consumption investment, and significantly improve the quality and efficiency of sludge dewatering treatment;

[0018] 3) Using microwave technology to detect sludge moisture content has higher accuracy and faster measurement speed;

[0019] 4) It has a high degree of automation and is equipped with an alarm system, which enables it to have a strong ability to deal with emergencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a first structural diagram of the precise dosing device for municipal sludge chemical modification agents in the utility model;

[0021] Figure 2 This is the second structural diagram of the precise dosing device for municipal sludge chemical modification agents in the utility model.

[0022] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0023] 1. Mixing tank, 2. Moisture content detection system, 3. Sludge flowmeter, 4. First modifier flowmeter, 5. First dosing pump, 6. First modifier storage tank, 7. Control system, 8. Concentration tank, 9. Sludge dewatering treatment equipment, 910. Feed pump, 920. Second dosing pump, 930. Modified concentrated sludge flowmeter, 940. Plate and frame filter press, 950. Second modifier storage tank, 960. Second modifier flowmeter, 10. Alarm system. DETAILED DESCRIPTION

[0024] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0025] Example 1

[0026] like Figure 1 As shown, a precise dosing device for a municipal sludge chemical modifier comprises: a stirring tank 1 and a moisture content detection system 2; a sludge flowmeter 3 is provided at the sludge inlet of the stirring tank 1, and a first modifier flowmeter 4 is provided at the modifier inlet of the stirring tank 1; the inlet of the first modifier flowmeter 4 is connected to the outlet of a first dosing pump 5, and the inlet of the first dosing pump 5 is connected to the outlet of a first modifier storage tank 6; the sludge flowmeter 3, the first modifier flowmeter 4, the moisture content detection system 2, and the first dosing pump 5 are respectively electrically connected to a control system 7; the moisture content detection system 2 is used to measure the moisture content of the sludge flowing into the sludge flowmeter 3;

[0027] The sludge flow meter 3 is used to measure the real-time sludge flow rate (Q1) and feed the sludge flow rate signal back to the control system 7. The control system 7 automatically compares the signal with the previous value. If the deviation is within 5%, the previous data is used. If the deviation exceeds the allowable range, the new value is used to avoid program operation overload and system failure caused by the instability of the sludge flow meter 3.

[0028] The moisture content detection system 2 is used to measure the moisture content of the sludge flowing into the sludge flow meter 3 and feed back the initial moisture content (P) signal to the control system 7. When the control system 7 receives the moisture content (P) signal transmitted by the moisture content detection system 2, the system automatically compares the received moisture content with the previous value. If the deviation is within 0.3%, the previous data is used. If the deviation exceeds the allowable range, a new value is used.

[0029] The first modifier flowmeter 4 is used to measure the real-time flow rate of the modifier at the outlet side of the first dosing pump 5 and feed back the modifier flow rate signal to the control system 7;

[0030] The absolute dry sludge addition ratio (w%) determined by experiment is set in the control system 7. The control system 7 automatically controls the addition of the modifier by adjusting the frequency of the first dosing pump 5 according to the following calculation formula based on the real-time sludge flow (Q1) fed back by the sludge flow meter 3:

[0031] Dosage (V1) = Q1 × (1-P) × sludge density (ρ1) × w% / reagent density (ρ2)

[0032] Dosing flow rate lower limit is set, when sludge flow meter 3 feedback flow Q1 < 25m 3 When the sludge flowmeter 3 fluctuates, the first dosing pump 5 is automatically shut down to prevent the empty pipe dosing phenomenon caused by the fluctuation of the sludge flowmeter 3;

[0033] Assuming that the dosage of the modifier is Q2, after the control system 7 receives the Q2 information, it compares Q2 with V1. When V1≠Q2 and the deviation exceeds 3%, the frequency of the first dosing pump 5 is automatically adjusted to realize flow tracking and correction of the dosage of the modifier. The sludge and the modifier enter the stirring tank 1 at the same time, and after being fully stirred, they enter the concentration tank 8 for concentration and precipitation, and finally enter the dehydration equipment for solidification treatment.

[0034] Example 2

[0035] like Figure 1 As shown, this embodiment is a further improvement on the basis of embodiment 1, specifically as follows:

[0036] The moisture content detection system 2 includes: a microwave transmitter and a signal processing system. The microwave transmitter is used to generate a microwave signal of a certain frequency, which is irradiated on the sludge surface and passes through the sludge. The signal generates energy loss through reflection and transmission (refraction and scattering) in the sludge medium and is collected. The microwave transmitter transmits the collected reflection and transmission signals to the signal processing system. The signal processing system is electrically connected to the control system 7. The signal processing system analyzes and processes the measured microwave signal based on the standard curve of attenuation of reflected and transmitted microwaves of sludge media with different moisture contents obtained through experiments, reversely infers the moisture content of the sludge, and transmits the moisture content (P) to the control system 7 through signals such as 4mA~20mA. The detection frequency of the moisture content detection system 2 is usually 1~2 times / day. If it operates 24 hours a day, it is 2~4 times / day. The detection frequency can be increased according to the changes in the amount of sewage.

[0037] Example 3

[0038] like Figure 1 As shown, this embodiment is a further improvement on the basis of embodiment 1, specifically as follows:

[0039] The discharge port of the stirring tank 1 is connected to the inlet of the thickening tank 8. The modified sludge in the stirring tank 1 will be sent to the thickening tank 8 for thickening treatment to obtain modified concentrated sludge.

[0040] In addition, the discharge port of the concentration tank 8 is connected to the inlet of the sludge dewatering treatment equipment 9, and the sludge dewatering treatment equipment 9 is electrically connected to the control system 7, that is, the modified concentrated sludge in the concentration tank 8 is sent to the sludge dewatering treatment equipment 9 for dewatering treatment.

[0041] Example 4

[0042] like Figure 2 As shown, this embodiment is a further improvement on the basis of embodiment 3, specifically as follows:

[0043] The sludge dewatering treatment equipment 9 includes: a feed pump 910 and a second dosing pump 920. The discharge port of the concentration tank 8 is connected to the inlet of the feed pump 910. The outlet of the feed pump 910 is connected to the inlet of the plate and frame filter press 940 via a modified concentrated sludge flow meter 930. The inlet of the second dosing pump 920 is connected to the outlet of the second modifier storage tank 950. The outlet of the second dosing pump 920 is connected to the inlet of the plate and frame filter press 940 via a second modifier flow meter 960. The modified concentrated sludge flow meter 930 is used to measure the inlet. The real-time flow rate of the modified concentrated sludge at the outlet side of the material pump 910, the second modifier flowmeter 960 is used to measure the real-time flow rate of the modifier at the outlet side of the second dosing pump 920, the modified concentrated sludge flowmeter 930, the second dosing pump 920 and the second modifier flowmeter 960 are respectively electrically connected to the control system 7, the modified concentrated sludge flowmeter 930 feeds back the measured real-time flow signal of the modified concentrated sludge to the control system 7, and the second modifier flowmeter 960 feeds back the measured real-time flow signal of the modifier to the control system 7.

[0044] Furthermore, the first modifier storage tank 6 stores PAC (polyaluminum chloride), and the second modifier storage tank 950 stores PAM (polyacrylamide).

[0045] Example 5

[0046] like Figure 1 As shown, this embodiment is a further improvement on the basis of embodiment 1, specifically as follows:

[0047] The control system 7 is electrically connected to the alarm system 10. The alarm system 10 is mainly used to deal with situations such as insufficient reagents and moisture content measurement values ​​not within the set range. When the initial moisture content measurement value of the sludge is not within the set range, the staff is reminded to make adjustments and suspend dosing to avoid loss of reagents. The first modifier storage tank 6 is provided with a liquid level lower limit sensor, and the liquid level lower limit sensor is electrically connected to the control system 7. When the modifier liquid level in the first modifier storage tank 6 is lower than the lower limit, the alarm system 10 is triggered. The alarm system 10 adopts an audible and visual alarm system, which triggers an indicator light and a bell alarm to remind the staff to replenish the modifier in time and stop dosing to prevent the first dosing pump 5 from idling and causing equipment damage. The control system 7 preferably adopts a PLC control system.

[0048] Examples

[0049] This example is a sludge mechanical dewatering project in a sewage treatment plant with a designed sewage treatment capacity of 120,000 m 3 / day, the actual sewage treatment capacity is about 50,000 to 100,000 m 3 / day, the water volume variation coefficient is large, and the daily sludge dewatering output is greater than 70 tons (calculated as 60% moisture content mud cake). The sludge is mainly composed of primary sludge and residual sludge. The ratio of primary sedimentation tank sludge to residual sludge is 1:2 to 1:4, and the moisture content of dewatered sludge is required to be below 60%. The original dewatering process uses polyferric sulfate (PFS) and polyacrylamide (PAM) as chemical modifiers. 25% concentration of PFS is added to the mixing tank 1 at a sludge to drug ratio of 30:1. After sufficient reaction, it is pumped to the plate and frame filter press 940 through the feed pump 910. PAM with a drug concentration of 1‰ is added to the rear end pipeline of the feed pump 910. The addition ratio is sludge: PAM = 20:1. The sludge properties and the ratio of primary sedimentation tank sludge to residual sludge continue to change with the sewage treatment volume and seasonal and periodic factory sewage discharge. The process has a long running time (3.2 hours / frame), a thin mud cake (<1.5 cm), and a high moisture content (>65%).

[0050] After the technical transformation, polyaluminium chloride (PAC) and polyacrylamide (PAM) are used as modifiers, a microwave transmitter and a sludge flowmeter 3 are set at the front end of the stirring tank 1 to detect the real-time moisture content of the sludge and the real-time flow of the sludge, and the real-time moisture content of the sludge and the real-time flow of the sludge are fed back to the control system 7. The control system 7 identifies the received real-time moisture content of the sludge and the real-time flow of the sludge through the set error range and selectively uses them. The absolute dry sludge addition ratio is set to 7% (28% solid PAC) and 0.18% PAM in the control system 7. The control system 7 uses the error range to determine the real-time moisture content of the sludge and the real-time flow of the sludge. The dosage of PAC is calculated based on the initial moisture content (P) of the treatment and the real-time flow rate (Q1) of the sludge, and the quantitative dosage of PAC is achieved by adjusting the frequency of the first PAC dosing pump 5. A first modifier flowmeter 4 is set at the rear end of the first dosing pump 5 to feed back the real-time flow rate of PAC in real time, and the feedback is sent to the control system 7 for comparison with the calculated PAC dosage (Q2). When V1≠Q2 and the deviation exceeds 3%, the frequency of the first dosing pump 5 is automatically adjusted to achieve flow tracking and correction of the PAC dosage. The sludge and PAC enter the stirring tank 1 at the same time, and after being fully stirred, they enter the concentration tank 8 for concentration and precipitation.

[0051] In order to avoid the shearing effect of the feed pump 910 from destroying the PAM floc network gel structure, PAM is added at the rear end of the feed pump 910. When the plate and frame filter press 940 is feeding, a modified concentrated sludge flowmeter 930 is set at the rear end of the feed pump 910 to feedback the real-time flow of the sludge after PAC modification and concentration, and feedback is fed back to the control system 7. The same method as the addition of PAM is used to achieve precise addition of PAM. Finally, the sludge enters the plate and frame filter press 940 for deep dehydration. After technical transformation, the use of the chemical modification agent precise dosing device greatly improves the sludge dehydration efficiency (operating time <2.35h / frame), the mud cake moisture content is less than 60%, and the thickness is greater than 2cm. The process flow of this project is as follows Figure 2 shown.

[0052] The utility model adds modifiers in a targeted manner based on the real-time moisture content and flow rate of the sludge, effectively solving the problems of inaccurate and insufficient chemical modification of the sludge when the sludge property variation coefficient is large due to irregular sewage volume and sludge ratio; sets the sludge absolute dry addition ratio, calculates the theoretical addition amount and uses flow tracking to adjust the dosing pump frequency, improves the accuracy of modifier addition, achieves sufficient modification of the sludge, greatly improves the sludge dewatering performance, ensures the subsequent sludge solidification efficiency, reduces production time cost and energy consumption investment, and greatly improves the quality and efficiency of sludge dewatering treatment.

[0053] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A precise dosing device for municipal sludge chemical modification agents, characterized in that: include: A stirring tank (1) and a moisture content detection system (2); a sludge flow meter (3) and a first modifier flow meter (4) are respectively provided at the sludge inlet and the modifier inlet of the stirring tank (1); the moisture content detection system (2) is used to measure the moisture content of the sludge flowing into the sludge flow meter (3); the inlet of the first modifier flow meter (4) is connected to the outlet of the first dosing pump (5); the inlet of the first dosing pump (5) is connected to the outlet of the first modifier storage tank (6); the sludge flow meter (3), the first modifier flow meter (4), the moisture content detection system (2) and the first dosing pump (5) are respectively electrically connected to a control system (7).

2. The precise dosing device for chemical modification of municipal sludge according to claim 1 is characterized in that: The moisture content detection system (2) includes: a microwave transmitter and a signal processing system. The microwave transmitter is used to generate a microwave signal of a certain frequency, which is irradiated on the sludge surface and passes through the sludge. The signal generates energy loss through reflection and transmission in the sludge medium and is collected. The microwave transmitter transmits the collected reflection and transmission signals to the signal processing system, and the signal processing system is electrically connected to the control system (7).

3. The precise dosing device for chemical modification of municipal sludge according to claim 1 is characterized in that: The discharge port of the stirring tank (1) is connected to the inlet of the concentration tank (8).

4. The precise dosing device for chemical modification of municipal sludge according to claim 3 is characterized in that: The discharge port of the concentration tank (8) is connected to the inlet of the sludge dewatering treatment equipment (9), and the sludge dewatering treatment equipment (9) is electrically connected to the control system (7).

5. The precise dosing device for chemical modification of municipal sludge according to claim 4 is characterized in that: The sludge dewatering treatment equipment (9) comprises: a feed pump (910) and a second dosing pump (920); the discharge port of the concentration tank (8) is connected to the inlet of the feed pump (910); the outlet of the feed pump (910) is connected to the inlet of a plate-and-frame filter press (940) via a modified concentrated sludge flowmeter (930); the inlet of the second dosing pump (920) is connected to the outlet of a second modifier storage tank (950); the outlet of the second dosing pump (920) is connected to the inlet of the plate-and-frame filter press (940) via a second modifier flowmeter (960); the modified concentrated sludge flowmeter (930), the second dosing pump (920) and the second modifier flowmeter (960) are respectively electrically connected to a control system (7).

6. The precise dosing device for chemical modification of municipal sludge according to claim 5 is characterized in that: The first modifier storage tank (6) stores PAC, and the second modifier storage tank (950) stores PAM.

7. The precise dosing device for chemical modification of municipal sludge according to claim 1 is characterized in that: The control system (7) is electrically connected to the alarm system (10), and a liquid level lower limit sensor is provided in the first modifier storage tank (6), and the liquid level lower limit sensor is electrically connected to the control system (7).

8. The precise dosing device for chemical modification of municipal sludge according to claim 7, characterized in that: The alarm system (10) adopts an audible and visual alarm system.

9. The precise dosing device for chemical modification of municipal sludge according to claim 1 is characterized in that: The control system (7) adopts a PLC control system.

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