Method for accurately adjusting pH value of wastewater of ammonia still

Abstract

The invention relates to a method for accurately adjusting the PH value of wastewater of an ammonia still, the method is completed through a system for accurately adjusting the PH value of the wastewater of the ammonia still, and the system for accurately adjusting the PH value of the wastewater of the ammonia still comprises the ammonia still, a wastewater delivery pump, a PH measuring instrument, an ammonia still operation interface, a variable-frequency controller and a liquid caustic soda adding metering pump, the ammonia still is connected with a wastewater delivery pump through a lower tower wastewater pipe, a PH measuring instrument is arranged on the lower tower wastewater pipe at the outlet end of the wastewater delivery pump, the PH measuring instrument is in remote transmission connection with an ammonia still operation interface, the ammonia still operation interface is connected with a variable-frequency controller, the variable-frequency controller is connected with a liquid caustic soda adding metering pump, and the liquid caustic soda adding metering pump is connected with the variable-frequency controller. The method has the beneficial effects that the ammonia nitrogen index of the lower tower wastewater of the ammonia still is more stable, the liquid caustic soda addition amount of the ammonia still is saved, the operation cost is saved, a suitable proliferation environment is created for subsequent biochemical treatment of microorganisms, and the treatment effect of a biochemical system is improved.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a method for accurately adjusting the pH value of wastewater from an ammonia distillation tower. Background Art

[0002] The ammonia evaporator is an important equipment for treating the residual ammonia water in the coking plant. By adding liquid alkali to the residual ammonia water entering the ammonia evaporator, the fixed ammonium salt can be decomposed in the ammonia evaporator, so as to achieve the purpose of recovering ammonia gas and reducing the ammonia nitrogen in the wastewater from the lower tower, creating conditions for the next biochemical treatment of the wastewater. Among the many control parameters of the wastewater from the lower tower of the ammonia evaporator, the control range of the pH value is directly related to the ammonia nitrogen index of the wastewater from the lower tower of the ammonia evaporator. However, it is very difficult to achieve accurate regulation of the pH value of the wastewater from the lower tower of the ammonia evaporator.

[0003] The traditional way to adjust the pH value is to manually measure the pH value of the wastewater in the lower tower of the ammonia evaporation tower, and then adjust the opening of the ammonia evaporation and alkali metering pump according to the pH value. The amount of ammonia water, fixed ammonium content, and steam volume in the upper tower of the ammonia evaporation tower will change, and the pH value will change accordingly. In order to achieve qualified ammonia nitrogen in the wastewater in the lower tower of the ammonia evaporation tower, most coking plants control the pH value of the wastewater in the lower tower between 8-10. However, this control range has a waste of liquid alkali dosage on the one hand, and on the other hand, it has an adverse effect on the proliferation environment of microorganisms in the subsequent biochemical treatment system. How to achieve accurate regulation of the pH value of the wastewater in the lower tower of the ammonia evaporation tower has become a difficult problem facing all ammonia evaporation tower operators in coking plants. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a method for accurately adjusting the pH value of wastewater from an ammonia distillation tower. The pH value of the lower tower wastewater sent out of the ammonia distillation tower is measured by arranging a pH meter on the lower tower wastewater pipe. The pH meter and the frequency conversion controller are interlocked by using the interlocking program of the ammonia distillation tower operation interface in the central control room. The frequency conversion adjustment frequency of the frequency conversion controller is controlled by the pH value measurement data of the pH meter, and then the motor speed of the liquid alkali metering pump is controlled, thereby controlling the amount of liquid alkali entering the ammonia distillation tower, so as to achieve the purpose of accurately adjusting the pH value of the wastewater from the ammonia distillation tower, and realizing that the pH value of the wastewater from the lower tower of the ammonia distillation tower can be accurately controlled from 8-10 to 7-7.5. Under the premise of ensuring that the ammonia nitrogen in the lower tower of the ammonia distillation wastewater is qualified, the amount of liquid alkali added can be saved, and favorable proliferation conditions for microorganisms in the subsequent biochemical system can be created, and the labor intensity of the operator of the ammonia distillation tower is greatly reduced.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for accurately adjusting the pH value of wastewater from an ammonia still, the method is completed by accurately adjusting the pH value system of wastewater from an ammonia still, the system comprising an ammonia still, a wastewater delivery pump, a pH meter, an ammonia still operation interface, a frequency conversion controller and a liquid alkali metering pump, the ammonia still is connected to the wastewater delivery pump through a lower tower wastewater pipe, a pH meter is arranged on the lower tower wastewater pipe at the outlet end of the wastewater delivery pump, the pH meter is remotely connected to the ammonia still operation interface, the ammonia still operation interface is connected to the frequency conversion controller, the frequency conversion controller is connected to the liquid alkali metering pump, the method for accurately adjusting the pH value of wastewater from an ammonia still specifically comprises the following contents:

[0007] S1. A pH meter is installed on the wastewater pipe of the lower tower of the ammonia distillation tower to measure the pH value of the wastewater of the lower tower of the ammonia distillation tower, and the measurement data is transmitted to the operation interface of the ammonia distillation tower in the central control room through the remote transmission line. The pH value alarm range of the wastewater of the lower tower of the ammonia distillation tower is set on the operation interface of the ammonia distillation tower, and the alarm range is 7 to 7.5;

[0008] S2, the operation interface of the ammonia evaporation tower controls the frequency conversion controller according to the pH value of the wastewater in the lower tower measured by the pH meter. When the pH value of the wastewater in the lower tower of the ammonia evaporation tower is greater than 7.5, the frequency conversion controller is closed at 0.1 Hz / min, and stops when it is closed to 30 Hz. When the pH value of the wastewater in the lower tower of the ammonia evaporation tower is less than 7.2, the frequency conversion controller is opened at 0.1 Hz / min, and stops when it is opened to 50 Hz;

[0009] S3. The frequency conversion controller controls the motor speed of the liquid alkali metering pump, thereby adjusting the amount of liquid alkali added to the ammonia evaporation tower. The adjustment accuracy of the frequency conversion controller is 0.1 Hz. The speed of the motor of the liquid alkali metering pump of the ammonia evaporation tower is adjusted by increasing or decreasing the value of the frequency conversion controller, and the amount of liquid alkali added to the ammonia evaporation tower is accurately controlled.

[0010] Furthermore, the system for accurately adjusting the pH value of wastewater from the ammonia distillation tower also includes a waste liquid collection well, which is arranged between the wastewater delivery pump and the pH measuring instrument, and the waste liquid collection well is connected to the lower tower wastewater pipe through a waste liquid pipe.

[0011] Furthermore, a sampling ball valve is provided on the waste liquid pipe.

[0012] Furthermore, the sampling ball valve is opened when the pH value of the lower tower wastewater is manually detected, so as to manually detect and calibrate the pH value of the lower tower wastewater of the ammonia distillation tower.

[0013] Furthermore, stop valves are provided on the waste water pipes under the tower at the front end and the rear end of the pH measuring instrument.

[0014] Furthermore, the frequency conversion controller is adjusted to a frequency range of 0 to 50 Hz.

[0015] Furthermore, in the step S2, the frequency conversion controller issues information prompts and sound and light alarms on the ammonia distillation tower operation interface at both 30 Hz and 50 Hz.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. By adjusting the amount of liquid alkali added through the frequency conversion controller, the fluctuation range of the pH value of the wastewater in the lower tower of the ammonia distillation tower is reduced to 7-7.5, the pH value range is narrowed, the ammonia nitrogen index of the wastewater in the lower tower of the ammonia distillation tower is more stable, and the ammonia nitrogen index in the wastewater is more accurate, which provides reliable data for the next step of wastewater treatment and creates conditions for the next step of biochemical treatment of wastewater.

[0018] 2. Accurately control the amount of liquid alkali added to further save the amount of liquid alkali added to the ammonia evaporation tower, save wastewater treatment costs, and improve economic benefits. Taking the residual ammonia water in the upper tower of 45 cubic meters per hour as an example, 1 ton of liquid alkali can be saved every day, 365 tons per year, or about 690,000 yuan.

[0019] 3. The pH value of the wastewater from the lower tower of the ammonia distillation tower is controlled at 7-7.5, which creates a suitable proliferation environment for subsequent biochemical treatment microorganisms, improves the efficiency of further biochemical treatment, and improves the treatment effect of the biochemical system.

[0020] 4. Greatly reduce the adjustment frequency and labor intensity of employees, improve the accuracy of wastewater pH value control, realize the automation of wastewater pH value control, avoid the impact of employees' untimely measurement or misoperation on the ammonia nitrogen index of the wastewater in the lower tower of the ammonia distillation tower, and reduce the impact of index fluctuations on subsequent biochemical systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention discloses a flow chart of a system for accurately adjusting the pH value of waste water from an ammonia distillation tower.

[0022] In the figure: P1. Ammonia still; P2. Wastewater delivery pump; P3. PH meter; P4. Ammonia still operation interface; P5. Liquid alkali metering pump; P6. Frequency conversion controller; P7. Waste liquid collection well; L1. Lower tower wastewater pipe; L2. Waste liquid pipe; F1. 1# stop valve; F2. 2# stop valve; F3. Sampling ball valve. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0024] like Figure 1As shown in the figure, the working principle of a system for accurately adjusting the pH value of wastewater from an ammonia distillation tower is as follows: through the interlocking program set on the operation interface P4 of the ammonia distillation tower, the pH measuring instrument P3 set on the wastewater pipe L1 under the ammonia distillation tower P1 and the frequency conversion controller P6 controlling the liquid alkali dosing metering pump P5 are interlocked and controlled. The pH measuring instrument P3 measures the pH value of the wastewater under the ammonia distillation tower P1, and the regulating frequency of the frequency conversion controller P6 is adjusted according to the pH value of the wastewater under the tower, and then the motor speed of the liquid alkali dosing metering pump P5 is controlled by the frequency conversion controller P6, thereby controlling the dosing. The amount of liquid alkali introduced into the ammonia still P1 can achieve the purpose of accurately adjusting the pH value of the wastewater in the lower tower of the ammonia still P1, and accurately control the pH value of the wastewater discharged from the lower tower of the ammonia still P1 between 7-7.5, creating a suitable proliferation environment for subsequent biochemical treatment microorganisms, creating conditions for the next biochemical treatment of wastewater, saving the amount of liquid alkali added to the ammonia still P1, saving wastewater treatment costs, greatly reducing the adjustment frequency and labor intensity of employees, improving the accuracy of pH value control of the wastewater in the lower tower, and realizing the automation of pH value control of the wastewater in the lower tower.

[0025] like Figure 1 As shown, a method for accurately adjusting the pH value of wastewater from an ammonia still is provided. The method is completed by accurately adjusting the pH value system of wastewater from an ammonia still. The system for accurately adjusting the pH value of wastewater from an ammonia still comprises an ammonia still P1, a wastewater delivery pump P2, a pH measuring instrument P3, an ammonia still operation interface P4, a frequency conversion controller P6 and a liquid alkali metering pump P5. The ammonia still P1 is connected to the wastewater delivery pump P2 through a lower tower wastewater pipe L1. A pH measuring instrument P3 is arranged on the lower tower wastewater pipe L1 at the outlet end of the wastewater delivery pump P2. The pH measuring instrument P3 is remotely connected to the ammonia still operation interface P4. The ammonia still operation interface P4 is connected to the frequency conversion controller P6. The frequency conversion controller P6 is connected to the liquid alkali metering pump P5. The method for accurately adjusting the pH value of wastewater from an ammonia still specifically comprises the following contents:

[0026] S1, a PH measuring instrument P3 is set on the wastewater pipe L1 of the lower tower of the ammonia distillation tower P1 to measure the PH value of the wastewater of the lower tower of the ammonia distillation tower P1, and the measurement data is transmitted to the ammonia distillation tower operation interface P4 of the central control room through the remote transmission line, and the PH value alarm range of the wastewater of the lower tower of the ammonia distillation tower P1 is set on the ammonia distillation tower operation interface P4, with a lower limit of 7 and an upper limit of 7.5;

[0027] S2, the ammonia evaporation tower operation interface P4 controls the frequency conversion controller P6 according to the pH value of the wastewater in the lower tower measured by the pH measuring instrument P3. The frequency conversion controller P6 is remotely connected to the ammonia evaporation tower operation interface P4 in the central control room through a line. When the pH value of the wastewater in the lower tower of the ammonia evaporation tower P1 is greater than 7.5, the frequency conversion controller P6 is closed at 0.1 Hz / min and stops at 30 Hz. When the pH value of the wastewater in the lower tower of the ammonia evaporation tower P1 is less than 7.2, the frequency conversion controller P6 is opened at 0.1 Hz / min until it stops at 50 Hz.

[0028] S3, the frequency conversion controller P6 controls the motor speed of the liquid alkali dosing pump P5, thereby adjusting the amount of liquid alkali added to the ammonia evaporation tower P1. The adjustment accuracy of the frequency conversion controller P6 is 0.1 Hz. The speed of the motor of the liquid alkali dosing pump P5 of the ammonia evaporation tower P1 is adjusted by increasing or decreasing the value of the frequency conversion controller P6, and the amount of liquid alkali added to the ammonia evaporation tower P1 is accurately controlled.

[0029] Install a DN15mm sampling ball valve F3 on the wastewater pipe L1 under the ammonia distillation tower P1, 1 meter away from the water inlet direction of the PH measuring instrument P3. The sampling ball valve F3 faces the ground. Make a DN100mm conical funnel 0.3 meters away from the sampling ball valve F3 and connect it to the waste liquid collection well P7 through the DN50mm waste liquid pipe L2.

[0030] The sampling ball valve F3 is used to manually detect and calibrate the pH value of the wastewater in the lower tower. The operator uses a portable pH meter or precision pH test paper to calibrate the results of the pH measuring instrument P3 every 6 hours to ensure the accuracy of the data of the industrial measuring instrument P3.

[0031] Furthermore, the system for accurately adjusting the pH value of wastewater from the ammonia distillation tower also includes a waste liquid collection well P7, which is arranged between the wastewater delivery pump P2 and the pH measuring instrument P3, and the waste liquid collection well P7 is connected to the lower tower wastewater pipe L1 through the waste liquid pipe L2.

[0032] Furthermore, 1# stop valve F1 and 2# stop valve F2 are set on the waste water pipe of the lower tower at the front end and the rear end of the pH measuring instrument. When the pH measuring instrument P3 needs to be replaced, the waste water delivery pump P2 is stopped, and the 1# stop valve F1 and the 2# stop valve F2 are closed at the same time, and the connection between the pH measuring instrument P3 and the waste water pipe L1 of the lower tower is cut off, so as to facilitate the removal of the pH measuring instrument P3.

[0033] Furthermore, the frequency conversion of the frequency conversion controller P6 is adjusted between 0 and 50 Hz.

[0034] Furthermore, in the step S2, the frequency conversion controller P6 issues information prompts and sound and light alarms on the ammonia evaporation tower operation interface P4 at 30 Hz and 50 Hz. When the information prompts and sound and light alarms are issued, the operator needs to immediately check whether there is any abnormality in the operation of the ammonia evaporation tower P1 and go to the site for confirmation.

[0035] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for accurately adjusting the pH value of wastewater from an ammonia still, which is accomplished by accurately adjusting the pH value of wastewater from an ammonia still, and is characterized in that: The system for accurately adjusting the pH value of wastewater from an ammonia still comprises an ammonia still, a wastewater delivery pump, a pH meter, an ammonia still operation interface, a frequency conversion controller and a liquid alkali dosing pump. The ammonia still is connected to the wastewater delivery pump via a lower wastewater pipe, a pH meter is arranged on the lower wastewater pipe at the outlet of the wastewater delivery pump, the pH meter is remotely connected to the ammonia still operation interface, the ammonia still operation interface is connected to the frequency conversion controller, and the frequency conversion controller is connected to the liquid alkali dosing pump. The method for accurately adjusting the pH value of wastewater from an ammonia still specifically comprises the following contents: S1. A pH meter is installed on the wastewater pipe of the lower tower of the ammonia distillation tower to measure the pH value of the wastewater of the lower tower of the ammonia distillation tower, and the measurement data is transmitted to the operation interface of the ammonia distillation tower in the central control room through the remote transmission line. The pH value alarm range of the wastewater of the lower tower of the ammonia distillation tower is set on the operation interface of the ammonia distillation tower, and the alarm range is 7 to 7.5; S2, the operation interface of the ammonia evaporation tower controls the frequency conversion controller according to the pH value of the wastewater in the lower tower measured by the pH meter. When the pH value of the wastewater in the lower tower of the ammonia evaporation tower is greater than 7.5, the frequency conversion controller is closed at 0.1 Hz / min, and stops when it is closed to 30 Hz. When the pH value of the wastewater in the lower tower of the ammonia evaporation tower is less than 7.2, the frequency conversion controller is opened at 0.1 Hz / min, and stops when it is opened to 50 Hz; S3. The frequency conversion controller controls the motor speed of the liquid alkali metering pump, thereby adjusting the amount of liquid alkali added to the ammonia evaporation tower. The adjustment accuracy of the frequency conversion controller is 0.1 Hz. The speed of the motor of the liquid alkali metering pump of the ammonia evaporation tower is adjusted by increasing or decreasing the value of the frequency conversion controller, and the amount of liquid alkali added to the ammonia evaporation tower is accurately controlled.

2. The method for accurately adjusting the pH value of ammonia distillation tower wastewater according to claim 1, characterized in that: The system for accurately adjusting the pH value of wastewater from the ammonia distillation tower also includes a waste liquid collection well, which is arranged between the wastewater delivery pump and the pH measuring instrument, and is connected to the lower tower wastewater pipe through a waste liquid pipe.

3. A method for accurately adjusting the pH value of ammonia distillation tower wastewater according to claim 2, characterized in that: A sampling ball valve is arranged on the waste liquid pipe.

4. A method for accurately adjusting the pH value of ammonia distillation tower wastewater according to claim 3, characterized in that: The sampling ball valve is opened when the pH value of the wastewater from the lower tower is manually detected, so as to manually detect and calibrate the pH value of the wastewater from the lower tower of the ammonia distillation tower.

5. The method for accurately adjusting the pH value of ammonia distillation tower wastewater according to claim 1, characterized in that: Stop valves are arranged on the waste water pipes under the tower at the front end and the rear end of the pH measuring instrument.

6. The method for accurately adjusting the pH value of ammonia distillation tower wastewater according to claim 1, characterized in that: The frequency conversion controller is regulated at 0-50 Hz.

7. The method for accurately adjusting the pH value of ammonia distillation tower wastewater according to claim 1, characterized in that: In step S2, the frequency conversion controller issues information prompts and sound and light alarms on the ammonia distillation tower operation interface at 30 Hz and 50 Hz.

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