CN101303303A - Circulating cooling water water quality stabilizer online automatic monitor - Google Patents

Abstract

The utility model relates to an on-line automatic monitor for a water quality stabilizer for circulating cooling water, relating to a monitor. An on-line automatic monitor for water quality stabilizers in circulating cooling water capable of realizing on-line detection and real-time control of the content of water quality stabilizers in industrial circulating cooling water is provided. Including incident light source, flow cell, signal filtering focusing device, signal conversion device and signal processing display device; the incident light source located on both sides of the flow cell excites the fluorescent tracer characteristic groups in the circulating water flowing through the flow cell, and the signal filtering focusing device Focusing and filtering the generated fluorescent signal, the signal conversion device converts the collected optical signal into a current signal, and amplifies the current signal to obtain a pulse signal with a corresponding frequency value; Perform processing and issue corresponding control signals, as well as input the set parameters and display the processing results. It has high sensitivity and accuracy, and can realize automatic addition and continuous detection of circulating water agents.

Description

Circulating cooling water water quality stabilizer online automatic monitor

technical field

The invention relates to a monitoring instrument, in particular to an online automatic monitoring device for an industrial circulating cooling water quality stabilizer.

Background technique

In the industrial circulating cooling water system of steel mills and power plants, the concentration of calcium and magnesium ions will cause scaling on the surface of water equipment or water treatment equipment, reduce heat transfer efficiency, and even block pipes, so various water quality stabilizers are widely used. In order to maintain the continuous effect of corrosion inhibition and scale inhibition, it is necessary to keep the content of water quality stabilizer in circulating water within a certain range. If the concentration is insufficient, the effect of the water treatment agent cannot be exerted; if the concentration is too high, it will cause waste and have a negative impact on the circulating water system. Therefore, how to quickly and accurately determine the concentration of water quality stabilizers is very important.

In the actual production process, since water quality stabilizers usually contain phosphorus, most units use manual sampling to detect the total phosphorus content of water samples and artificially add water quality stabilizers. This method is time-consuming and laborious, and the time to obtain data lags behind the actual , It is impossible to control the concentration of water quality stabilizer in real time. Although the total phosphorus content determination analyzer has been put into commercial use, such as the Phosphax ΣSigma total phosphorus online analyzer of the American Hach Company, under high temperature and high pressure, it adopts the acidic potassium persulfate rapid digestion method, and it takes about 10 minutes to measure a sample. The detection principle is still the same as the manual analysis method, which requires the addition of a variety of chemicals, a large amount of instrument maintenance, and a long sampling cycle, which is not suitable for use in circulating water systems.

Foreign water treatment companies are relatively advanced in monitoring technology, and have developed some on-line monitoring and control instruments, which are used in actual production. In the early 1990s, Nalco Corporation of the United States developed a technology called TRASAR. Its determination method is to link fluorescent groups to the active ingredients of water quality stabilizers, and use an online fluorescence detector to detect its fluorescence intensity to control water quality in real time. agent content. There are very few units that introduce this technology in our country, the main reason is that the price of this water quality stabilizer is expensive.

Contents of the invention

The object of the present invention is to provide an on-line automatic monitor for water quality stabilizers in circulating cooling water that can realize on-line detection and real-time control of the content of water quality stabilizers in industrial circulating cooling water.

The invention is provided with a left incident light source and a right incident light source, a flow cell, a signal filtering focusing device, a signal conversion device, a signal processing display device, a computer, an RS232 serial interface and a feeding pump; the signal filtering focusing device is provided with a focusing lens and a narrow band filter The light sheet, the signal conversion device is equipped with a photoelectric converter and signal preamplifier, the signal processing and display device is equipped with a control processor, a display screen and a keyboard; the left incident light source and the right incident light source are located on both sides of the flow cell, and the focusing lens is located Below the flow cell, the narrow-band filter is set under the focusing lens. The filtered light beam of the narrow-band filter is converted by the photoelectric converter, and the output terminal of the electrical signal is connected to the I/O port of the control processor and the input terminal of the display screen. Connect to the I/O port of the control processor, the output terminal of the keyboard is connected to the I/O port of the control processor, the I/O port of the control processor is connected to the RS232 serial port of the computer through the RS232 serial interface, the feeding pump and the control processor I/O port connection.

The left incident light source and the right incident light source can adopt high-brightness monochromatic light-emitting diodes, halogen lamps with optical filters or laser light sources. The flow cell can be a quartz glass tube. Display screen can adopt liquid crystal display screen.

In addition, the present invention can be provided with an RS232 serial interface, connected with equipment such as a printer, so as to save and print the detected data, and can also realize the control of the timing start detection of the instrument.

The left incident light source and the right incident light source located on both sides of the flow cell excite the fluorescent tracer characteristic groups in the circulating water flowing through the flow cell, and the signal filtering and focusing device performs light focusing and filtering on the generated fluorescent signal, and the signal conversion device will The collected optical signal is converted into a current signal, and the current signal is amplified to obtain a pulse signal with a corresponding frequency value; the control processor processes the frequency pulse signal and sends a corresponding control signal, and the instrument parameters are input through the keyboard to set The parameters and processing results are displayed on the display.

Based on the fluorescent tracer technology, the present invention optimizes the performance of the key modules of the instrument, realizes high-precision and stable detection of weak fluorescent signals, and ensures the reliability of the instrument performance. Due to the use of fluorescent tracer technology, it indirectly monitors and timely controls the content of water quality stabilizers in circulating cooling water. Compared with the total phosphorus content determination analyzer that has been put into commercial use, the design of the instrument is simpler, and the measurement of samples is easier. The cycle is shorter. Therefore, it is very suitable for monitoring and controlling the concentration of water quality stabilizers in circulating cooling water systems in industry. It has the following characteristics:

1) The operation is simple and the degree of automation is high, which can realize the online detection and real-time control of the water quality stabilizer content of the circulating cooling water, saving a lot of manpower and material resources.

2) The measurement results have high precision, the detection limit of the instrument can reach 1mg/L, and the instrument can be calibrated frequently to ensure the reliability of the detection data.

3) After replacing the inert fluorescent tracer, the light source and filter of the monitor, it can be applied to any other online monitoring occasions where the fluorescent tracer technology is applicable, and has broad market prospects and significant social and economic benefits.

Description of drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

FIG. 2 is a system program flow of the embodiment of the present invention.

FIG. 3 is a pin diagram of a control processor according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of circuit composition of a signal conversion device and a signal processing and display device according to an embodiment of the present invention.

Fig. 5 is a graph showing the correlation between the fluorescent tracer concentration and the total phosphorus concentration in an embodiment of the present invention. In Fig. 5, the abscissa is the total phosphorus concentration (μg/mL), and the ordinate is the fluorescent tracer concentration (ng/mL), where y=58.553X+68.105, R ² =0.969.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings.

Referring to Fig. 1, the present invention is provided with left incident light source 31 and right incident light source 32, flow cell 2, signal filter focusing device, signal conversion device, signal processing display device, RS232 serial interface 11, feeding pump 12 and computer 13; The filter focusing device is provided with a focusing lens 4 and a narrow-band filter 5, the signal conversion device is provided with a photoelectric converter 6 and a signal preamplifier 7, and the signal processing and display device is provided with a control processor 8, a liquid crystal display 9 and a keyboard 10; The left incident light source 31 and the right incident light source 32 are arranged on both sides of the flow cell 2, the focusing lens 4 is positioned at the bottom of the flow cell 2, and the narrow band filter 5 is arranged at the bottom of the focusing lens 4, and the filtered light beam of the narrow band filter 5 The output terminal of the electrical signal converted by the photoelectric converter 6 is connected to the I/O port of the control processor 8, the input terminal of the liquid crystal display 9 is connected to the I/O port of the control processor 8, and the output terminal of the keyboard 10 is connected to the control processor 8, the I/O port of the control processor 8 is connected to the RS232 serial interface of the computer 13 through the RS232 serial interface 11, and the feeding pump 12 is connected to the I/O port of the control processor 8.

Through the bypass pipe of the circulating cooling water pipe, a small amount of circulating water sample 1 is led to the flow cell 2 in real time; the opposite left incident light source 31 and right incident light source 32 excite the fluorescent tracer characteristic groups in the circulating water with a certain frequency pulse, Fluorescent signals of specific wavelengths are generated. After focusing and filtering the generated fluorescent signals by focusing lens 4 and narrow-band filter 5, the signals are sent to photoelectric converters (silicon photodiodes) 6 to convert weak optical signals into weak Current signal; the signal preamplifier 7 amplifies the current signal to obtain a pulse signal with a corresponding frequency value; the control processor 8 collects the frequency signal, calculates the concentration of the fluorescent tracer in water, and calculates the concentration of the fluorescent tracer in water according to the water quality stabilizer and fluorescent tracer The concentration value of the current water quality stabilizer is converted from the dosage ratio of the agent. This numerical value can not only be displayed on the liquid crystal display screen 9 of the on-line monitor, but also can be sent to the computer 13 for display through the RS232 serial interface 11 using the RS232 protocol. The control processor 8 can also compare the measured concentration value with the set limit value, control the opening and closing of the feeding pump 12 for adding the water quality stabilizer, and keep the water quality stabilizer within the required range. The keyboard 10 is used to input instrument parameters.

Refer to FIG. 2 for the system program flow of the present invention.

The function first completes the initialization of the single-chip microcomputer system, displays the boot interface on the LCD screen, then reads the fixed parameters, scans the keyboard, and makes a judgment. If you press the START key, the sample concentration detection will be carried out; if you press the MENU key, the setting interface will be switched, including four setting interfaces such as calibration setting, timing interval setting, defined concentration setting and display time adjustment. Set the parameters of each interface according to the situation.

The control processor is composed of single-chip microcomputer HT46R24, clock chip BL5732, RS232 level conversion chip MAX232N, serial EPROM AT24C256 memory chip (storage font and system fixed parameters), high-power NMOS tube IRF630 (drive feeding pump), and timing chip LM555. 1kHz multivibrator (to drive the incident light source), and the drive interface circuit of the film key and liquid crystal module AM128128, etc.

The input and output control of the single-chip microcomputer (as shown in Figure 3) is as follows: ports 1, 2, 27, 28 are row-input control signal lines of the keyboard, ports 3, 4, 5, and 6 are column input control signal lines of the keyboard, and the keyboard It is a 4×4 determinant keyboard input control. After the system is powered on and reset, it starts to call the keyboard scanning subroutine to scan the input ports of the 4×4 determinant keyboard. The PB4~PB7 ports in the microcontroller are used as the row input ports of the keyboard. The ~PA3 port is used as the column input port of the keyboard. If a key is pressed, it will be scanned again with a delay of 10ms; if there is still a key pressed, the key query subroutine is called to inquire and deal with accordingly. Ports 7, 8, 9, 10, 12, and 13 are the output control signal lines of the liquid crystal display. The liquid crystal display is FSTN, and the dot matrix format is 128×128. Each port of the MCU corresponds to the pins of the LCD screen, port 7 corresponds to the chip selection port of the S6B0741 controller of the LCD screen, port 8 corresponds to the background enabling port of the LCD screen, and port 9 corresponds to the LCD screen The reset signal terminal of the S6B0741 controller, port 10 corresponds to the serial data signal terminal of the LCD display, port 12 corresponds to the command and data selection signal terminal of the LCD display, and port 13 corresponds to the serial port clock signal of the LCD display end. After the instrument is started, the stored words are recalled from the memory EPROM AT24C256 and displayed on the LCD. Ports 25 and 26 are connected to the T2IN and R2OUT pins of the level conversion chip MAX232N, and use the asynchronous transmission mode of the USART for data transmission. Port 18 is the frequency signal line output by the preamplifier module, and port 24 is the feed pump output control signal line.

Referring to Figure 4, the silicon photodiode converts the received fluorescent signal into a weak current signal, and the current signal is pre-amplified through an integral amplifier circuit composed of an operational amplifier CA3140. The RC value of the amplifier makes its frequency bandwidth reach 4.976kHz, much wider than the fluorescence signal bandwidth of 1kHz. After the amplified fluorescent signal passes through the capacitor _C4 , the DC noise interference signal will be filtered out, and the waveform will move down as a whole, and then it will be detected by the amplifier AD706, and only the positive level will be retained. After the second-order active integral low-pass filter with a cutoff frequency of 6Hz further filters out the noise in the high frequency band, the fluorescent signal changes from a 1kHz alternating signal to a direct current signal, and the signal becomes a corresponding signal after passing through the V/F converter of AD650 A pulse signal with a frequency value.

An example of use of the present invention is given below:

Add 250L steel mill circulating water make-up water to the circulating cooling water dynamic simulation device as the circulating cooling water of the system. According to the ratio of 250 μg of fluorescent tracer and 50 mg of water quality stabilizer per liter of water, that is, the concentration of fluorescent tracer and water quality stabilizer is 1:200, add reagents, and operate the device.

Before using the present invention to measure water samples, it is necessary to calibrate and correct the instrument first. According to the concentration value of the fluorescent tracer in the water sample, the upper and lower standard solutions covering the concentration value of this point are prepared to reduce the measurement error. , the difference between the concentration values of the superscript and subscript solutions should not be too large. Generally, the concentration of the subscript solution is set to half of the concentration of the water sample; the concentration of the superscript solution is set to twice the concentration of the water sample. For example, the initial concentration of this dynamic simulation experiment is 250ng/mL, and the concentration values of the configured upper and lower calibration solutions are 100ng/mL and 500ng/mL respectively.

After the power is turned on, the LCD screen enters the boot interface, press the "MENU" key to enter the first setting interface, press the "ENTER" key to confirm, and operate the interface, and the "*" selection pointer will appear at this time, press the "ENTER" key " to select "Calibration Lower Limit", then press "CLR" to clear the previously saved calibration concentration value, and input the required calibration lower limit solution concentration value: 100ng/mL. Click the "ENTER" button to confirm, and then press the "START" button, the instrument enters the calibration operation, the interface displays: "Calibration lower limit: 100ng/mL", exit the display interface after about one minute, and end the calibration of the substandard solution operate. According to the above operations, perform superscript solution calibration operation on the instrument.

In the first setting interface, set the defined concentration value and timing interval. After setting the parameters, exit to the start-up interface, press the "START" button to switch to the sample detection interface to detect the concentration of the fluorescent tracer in the current water sample. Refresh the currently detected concentration value every second, and after 3 minutes, calculate the average value of the last 10 sets of data as the final measurement result.

Water samples were measured every 2 hours, and the concentration of fluorescent tracers was continuously monitored online for 24 hours; while the automatic monitor was analyzing, water samples were taken for routine chemical analysis of total phosphorus. Preliminary experiments show that the fluorescent tracer has excellent stability and anti-interference ability, and other substances have no effect on it except that the intensity is attenuated by the biocide. Therefore, after the experiment was carried out for a period of time, oxidizing biocides and non-oxidizing biocides were added according to the dosage of the daily operation of the factory, and their effects on the fluorescent tracer were observed respectively. The experiment lasted for 6 days, and a total of 72 data points were obtained.

Comparing the data of the two methods, the linear correlation curve between the fluorescent tracer concentration and the total phosphorus concentration is obtained, and its linear fitting equation is: y=58.553x+298.11 (n=72, R ² =0.969), where y is Fluorescent tracer concentration (ng/mL), x is total phosphorus concentration (μg/mL). The correlation curve between the fluorescent tracer concentration and the total phosphorus concentration in Figure 5 shows that under the condition of the presence of interfering substances such as biocides, there is still a good correlation between the fluorescent tracer concentration and the total phosphorus concentration, and it is completely possible By monitoring the concentration of fluorescent tracers, the concentration of water treatment chemicals can be monitored indirectly.

Claims (5)

1. on-line automatic monitoring instrument of circulation cooling water quality stabilizing agent is characterized in that being provided with left incident light source and right incident light source, flow cell, filtering signals focalizer, chromacoder, signal Processing display device, computing machine, RS232 serial line interface and charge pump; The filtering signals focalizer is provided with condenser lens and narrow band pass filter, and chromacoder is provided with photoelectric commutator and signal preamplifier, and the signal Processing display device is provided with processor controls, display screen and keyboard; Left side incident light source and right incident light source are located at the both sides of flow cell, condenser lens is positioned at the below of flow cell, narrow band pass filter is located at the below of condenser lens, narrow band pass filter leach the I/O mouth that the electrical signal of light beam after photoelectric commutator conversion connects processor controls, the I/O mouth of the input termination processor controls of display screen, the output termination processor controls I/O mouth of keyboard, the I/O mouth of processor controls connects the RS232 serial line interface of computing machine by the RS232 serial line interface, and charge pump is connected with the I/O mouth of processor controls.

2. on-line automatic monitoring instrument of circulation cooling water quality stabilizing agent as claimed in claim 1 is characterized in that left incident light source and right incident light source are the high brightness single color LED, add the Halogen lamp LED or the LASER Light Source of optical filter.

3. on-line automatic monitoring instrument of circulation cooling water quality stabilizing agent as claimed in claim 1 is characterized in that flow cell is a quartz glass tube.

4. on-line automatic monitoring instrument of circulation cooling water quality stabilizing agent as claimed in claim 1 is characterized in that display screen is a LCDs.

5. on-line automatic monitoring instrument of circulation cooling water quality stabilizing agent as claimed in claim 1, it is characterized in that processor controls is provided with the multivibrator of the 1kHz of HT46R24 single-chip microcomputer, clock chip BL5732, RS232 level transferring chip MAX232N, Serial E PROMAT24C256 storage chip, high-power NMOS pipe IRF630, timing chip LM555 formation, and the driving interface circuit of film key and Liquid Crystal Module AM128128.

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