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ABSTRACT

The content of the abstract


Introduction

The most familiar and the most incredible substance on Earth – water. The value of water is impossible be overemphasized in the life all living things on the planet. Being the predominant element in the composition of organism, water leads and his life. Everyone knows the expression “water is life”, therefore, at present, the environmental problem of pollution of water bodies (rivers, lakes, groundwater, etc.) is the most urgent. The modern pace of development of industry and agriculture every year requires increasing amounts of water resources to meet the needs of cities, towns, factories, factories, as well as for irrigation farming systems. It is obvious that simultaneously with the increase in water consumption by industry and agriculture, its pollution is also growing, since the main source of water pollution is wastewater.

Qualitative and quantitative determination of the composition of contaminants in the effluent is necessary not only to select the technology of their treatment, but also to comply with the norms of discharge of treated wastewater into water bodies. Existing standards of maximum permissible concentration of petroleum products in water are established for petroleum products and their fractions.

Oil and petroleum products are one of the main pollutants. Therefore, all industries have the task of controlling the emission of pollutants (oil and its fraction) into the environment.


1. Theme urgency

Currently, wastewater treatment plants are inefficient due to the moral and physical deterioration of equipment, lack of staff qualifications, due to lack of data for decision-making. This is due to the fact that a number of parameter values are difficult to determine due to the lack of appropriate measurement tools.

Harsh operating conditions with the imperfection of the technological regime lead to systematic violations of working conditions. Attempts to improve the operation of existing facilities by changing the sewage intake system, increasing the flow rate of air supplied by additional installations, are often technically difficult to implement and lead to insignificant results. Therefore, the best way out is to use water intake to monitor and predict the concentration of petroleum products.


2. Goal of the research

Develop a device for monitoring the concentration of petroleum products in the wastewater of an industrial enterprise


3. Tasks of the research

To achieve this goal it is necessary to study and solve the following tasks:

  1. Sources of water pollution, methods and means of cleaning them.
  2. Analyze existing methods for determining the concentration of petroleum products в сточных водах промышленного предприятия, выбрать метод, который позволит более точно обнаружить нефтепродукты в воде.
  3. Develop a block diagram of the device for measuring the concentration of petroleum products in the wastewater of an industrial enterprise.
  4. Develop a mathematical model and configure it for a device for measuring the concentration of petroleum products in the wastewater of an industrial enterprise.
  5. Evaluation of metrological parameters and characteristics of the control device.

4. The method of infrared spectrometry to determine the concentration of petroleum products

As a result of the review, the method of infrared-spectrometry was chosen[6]. The advantage of the method is a smaller loss of light fractions than when determining oil products by other methods. The lower limit of the measurement range is 0.05 mg/l. The main advantage of the method is the weak dependence of the analytical signal on the type of oil product that forms the basis of sample contamination.

Disadvantages: the inability to register weak signals due to the small signal-to-noise ratio, which occurs when the concentration of petroleum products is in hundredths of the maximum permissible concentration (MAC) or less.

5. Development of a primary transducer

The measuring transducer implements the method of IR non-dispersive spectrometry. Diagram of the measuring transducer is shown in Figure 2.[8]

Figure 2 – Primary Measuring Converter

The basis of the measuring processes is the absorption of optical radiation by petroleum products in the region of 3.4 microns. The absorption spectrum is shown in Figure 3.

Figure 3 – The absorption spectrum of petroleum products

The absorption spectrum for performing analytical calculations is approximated by a set of simplest spectra according to the following description:


5.1 Selection of radiation source and receiver

LED–34PR type LEDs with parameters and characteristics can be used as a radiation source: the range is from 1600 to 3600 nm and the service life is more than 10,000 hours. The parameters are presented in table 2.[9, 10]

Table 2 – Parameters of LED–34PR

PD36-03-TEC-PR with characteristics can serve as a photodetector: with a range from 1500 to 3800 nm. The parameters are presented in table 3.

Table 3 – Parameters of PD36–03–TEC–PR

The spectral response is shown in Figure 5.

Figure 5 – Spectral response

Information in the signal is formed as a result of the interaction of optical radiation with a substance (petroleum product). The interaction is described as a change in the spectral composition of optical radiation due to the absorption of individual spectral components of the optical signal NP.

Using a mathematical model of the measuring transducer, the dependence of the photocurrent on the concentration of the NP is constructed.

Figure 6 – Dependence of photocurrent value (µA) on concentration (mg/l)

The resulting dependence is a characteristic of the conversion of the concentration of the NP in the output signal of the converter - the photocurrent.


5.2. Evaluation of metrological characteristics

To estimate the instrumental error, a random stationary signal was supplied to the model input, having a dimension of the concentration of oil products in the range from 0 to 10 mlg/l. The test signal selected is the worst type for the measuring system. By virtue of the principle of maximum entropy with a normal probability density distribution, the values of the signal of measurement errors turn out to be maximum, therefore, with any other laws of the distribution of the actual measurement signal, the errors will not exceed the estimates obtained.

The test signal is generated by the procedure. Mathcad rmd. This is the procedure for generating pseudo-random numbers, the spectrum of which corresponds to white noise. White noise is then passed through a 6-order filter and acquires the character of a random stationary process with a spectrum equal to the spectral characteristic of the filter. The parameters and characteristics of the output signal of the filter were established in the course of the work in the disciplines Theoretical Foundations of Measuring Instruments and Systems and Measuring transducers. The method of analysis is described in the works. [11, 12].

The test signal is input as an input signal to the measuring instrument model. The values of the input signal are further considered as the true value of the measured value, with which the comparison of the measurement results obtained by the scaling algorithm is carried out. 500 measurements are performed. Estimates of static parameters of measurement error are set by the formulas

As a result of the simulation, the following estimates of the error parameters of the measuring instrument were obtained:

The resulting model does not take into account a number of factors, such as:

Measurement errors of the device can be reduced to additive and multiplicative components and in the process of analysis are automatically eliminated by means of a microprocessor system.


Conclusions

In the work carried out: