RU2047857C1 - Device for automatic control of waste gases composition - Google Patents

Abstract

FIELD: mining engineering. SUBSTANCE: device has infrared radiation source with collimator and photoreceptor with modulator placed on the opposite sides of gas volume under control having thickness d, indicating and registering unit, five transducers, difference measuring units, three relation measuring units, difference measuring unit and relation measuring unit connected in series, additional photoreceptor, calculating unit, relation measuring unit, three difference measuring units and ten circuits made of amplifier and band filter connected in series, where an additional photoreceptor is placed outside of collimated infrared radiation beam behind the modulator, both photoreceptors being five-banded with registering radiation wavelengths 1.3-1.7 mcm, 3.0-3.4 mcm, 4.1-4.5 mcm, 4.5-4.7 mcm and 7.6-7.8 mcm. EFFECT: enhanced accuracy of control. 7 dwg

Description

 The invention relates to mining automation, and more specifically to monitoring the composition of exhaust gases, and can be used to control the furnaces of power plants, boiler houses and other thermal installations in which coal or fuel oil is burned, as well as to control the ventilation and dust collection of coal mines and various enterprises.

Known absorption gas analyzer containing a radiation source, a radiation flux modulator located on the optical axis of the radiation source, comparative and measuring optical channels, including comparative and measuring cuvettes with filters, a radiation receiver optically coupled to said cuvettes and a recording device in which to increase accuracy and sensitivity measuring cuvettes are located under the comparative cuvette parallel to one another, and the radiation flux modulator is made in the form of pairs a prism aligned diagonally with the ability to move the prisms in each pair, one relative to the other, normal to the surface of their separation, with half of the pairs of prisms installed at the entrances of the ditches, and the other half at the exits [1]
A disadvantage of the known device is the low accuracy associated with the influence of fluctuations in the dust content and neglect of the true concentration of dust.

A device for automatically controlling the composition of exhaust gases, comprising installed against each other on opposite sides of a controlled volume of gas of thickness d, an infrared radiation source with a collimator and a photodetector with a modulator, an indication and registration unit, five adjusters, a difference meter, three ratio meters, connected in series difference meter and ratio meter, which is equipped with a rotary shutter with two movable collimators, a storage unit to increase accuracy I-samples, a logarithm, two multiplication units, a pulse generator, a frequency divider controlled by a switch, a target from a series-connected second storage-sample unit, a second logarithm, random access memory, two difference meters and a ratio meter, as well as a chain of a third connected in series storage-sample unit and three relationship meters, the information input of the managed switch being connected to the output of the infrared photodiode, the first control input being connected n with the first output of the pulse generator, the second control input is connected to the input of the storage device and to the output of the frequency divider, the input of which is connected to the second output of the pulse generator, and the outputs of the managed switch are connected to the inputs of the storage-sample units, the output of the first of which is connected to the second input the second relationship meter, and the output of the third storage-sample unit through the first logarithm is connected to the second input of the first difference meter, the outputs of the first and fourth relationship meters are connected s with the second and third inputs of the threshold unit, the fourth input of which is connected to the second master, the output of the third relationship meter is connected to the first input of the multiplication unit, the second input of which is connected to the third master, and the output is connected to the second input of the second difference meter, the second input of the third meter relations is connected to the fourth master, the second input of the fourth meter is connected to the fifth master and the first input of the second multiplication unit, the second input of which is connected to the sixth master, and the output connected to the second input of the first relationship meter, while the fixed collimator is made expandable and installed at the infrared laser LED with the wide side to the infrared photodiode, the first movable collimator is made tapering and installed in front of the infrared photodiode of one shutter blade with the narrow side to the LED, and the second movable collimator is made circular and mounted on the second blade of the shutter [2]
The disadvantages of the known device are the inability to measure the contents of dust, coal, moisture, carbon monoxide and carbon dioxide in the exhaust gases and the low accuracy of the measurements due to the influence of changes in the intensity of infrared radiation, pollution of the source and photodetector windows and changes in the temperature of the exhaust gases.

 The aim of the invention is to expand the functionality by additionally measuring the contents of dust, coal, moisture, carbon monoxide and carbon dioxide in the exhaust gases while improving accuracy by eliminating the effects of changes in the intensity of infrared radiation, pollution of the source and photodetector windows and changes in temperature of the exhaust gases, as well as simultaneous simplification of the device.

 The goal is achieved by the fact that the device for automatic control of the composition of the exhaust gases, containing installed opposite each other on a controlled volume of gas of thickness d, an infrared radiation source with a collimator and a photodetector with a modulator, an indication and registration unit, five adjusters, a difference meter, three ratio meters connected in series to a difference meter and a ratio meter, is equipped with an additional photodetector, a computing unit, a ratio meter, three meters difference fuses and ten circuits from a series-connected amplifier and a band-pass filter, with an additional photodetector installed outside the collimated infrared beam behind the modulator, both photodetectors are made five-band for the wavelengths of the detected radiation 1.3-1.7, 3.0-3.4 , 4.1-4.5, 4.5-4.7 and 7.6-8.4 microns, while the outputs of the photodetectors are connected to the inputs of the amplifiers, the outputs of the five bandpass filters from the outputs of the additional photodetector are connected to the first inputs of the difference meters, to the second entrance where the outputs of the adjusters are connected, the outputs of the difference meters are connected to the first inputs of the ratio meters, the outputs of five bandpass filters from the outputs of the photodetector are connected to the second inputs of the outputs, the outputs of five ratio meters are connected to the inputs of the computing unit, the output of which is connected to the input of the indication and registration unit.

 An inventive act in creating a device consists in overcoming a technical contradiction. The essence of the contradiction is as follows. To expand the functionality in conventional engineering design, the device is complicated by the introduction of additional channels. To eliminate each influencing action, a special corrective signal about the action is obtained, which also complicates the device. In the proposed device, the expansion of functionality and increased accuracy by eliminating the influence of three strong disturbing factors are achieved simultaneously not only without additional complication of the device, but also by simplifying the device compared to the prototype. To overcome the technical contradiction, all the distinguishing features of the device are necessary and sufficient: 1) an additional photodetector, 2) a computing unit, 3) a ratio meter, 4) three difference meters, 5) ten circuits from the amplifier and a bandpass filter connected in series, 6) an additional photodetector is installed outside the collimated infrared beam behind the modulator, 7) both photodetectors are made five-band at the wavelengths of the detected radiation 1.3-1.7, 3.0-3.4, 4.1-4.5, 4.5-4, 7 and 7.6-8.4 microns; 8) photo outputs receivers are connected to the inputs of amplifiers, 9) the outputs of five bandpass filters from the outputs of an additional photodetector are connected to the first inputs of difference meters, 10) the outputs of the adjusters are connected to the second inputs of the difference meters, 11) the outputs of the difference meters are connected to the first inputs of the ratio meters, 12) to the second the outputs of the relationship meters are connected to the outputs of five bandpass filters from the outputs of the photodetector, 13) the outputs of the five relationship meters are connected to the inputs of the computing unit, 14) the output of the computing unit the eye is connected to the input of the display and registration unit. The first fifth, eighth and 14th signs are known individually by themselves, however, to overcome the technical contradiction, i.e. to achieve their goals, they have never served before. The remaining seven signs are unknown even individually by themselves. If you exclude or replace with an equivalent one of any of the 14 distinctive features, the goal will not be achieved. This clearly follows from the description below. Therefore, a set of 14 distinctive features meets the criteria of "novelty" and "inventive step".

Figure 1 shows the attenuation spectra of infrared radiation (hereinafter IR radiation) with moisture H ₂ O, CO, CH ₄ , N ₂ O, O ₃ , CO ₂ , HDO and the solar IR spectrum; figure 2 dependence of the attenuation coefficients of infrared radiation of coal dust (curve 1), limestone dust (curve 2), sandstone dust (curve 3) on wavelength λ; in Fig.3 the dependence of the intensity of the transmitted I _p and forward scattered I _p IR radiation through a smoke layer of thickness d on the total dust content C _p in the exhaust gases; in Fig.4 the dependence of the ratio of intensities η _p = I _p / I _p from C _p at 0 <C _p <170 g / m ³ ; figure 5, the relationship of the ratio η _p I _p / I _p from C _p at 170 g / m ³ <C _p <340 g / m ³ ; figure 6 dependence of the absolute values of the relative sensitivity of the past S _p | and forward scattered S _p | IR radiation to the total dust content in the smoke C _p on the content of C _{p itself} , as well as the dependence of the absolute value of the relative sensitivity of the ratio S _o | from C _p ; 7 is a functional diagram of a device for automatically controlling the composition of exhaust gases.

 The invention is illustrated by the following circumstances.

The intensity of the infrared radiation transmitted through the smoke layer of thickness d _p Ip exponentially decreases with increasing total dust content in the smoke C _p according to the formula
I _p I _op exr (-K _p dC _p ), (1) where I _{op is the} intensity of transmitted infrared radiation at C _p 0; To _p the attenuation coefficient of infrared radiation by dust. If d is measured in meters (m), and the content of C _p is measured in g / m ³ , then to obtain the dimensionless product K _p C _p d, the coefficient K _p must be expressed in m ² / g.

The intensity of the infrared radiation I _p scattered in the forward direction in the smoke layer of thickness d _p varies with C _p according to the formula
I _p I _оp + σ _p dC _p exр (- К _p dC _p ), (2) where I _{Оp is the} intensity of forward scattered IR radiation at С _p 0; σ _p - the coefficient of dispersion of infrared radiation by dust, K _p the attenuation coefficient of forward-scattered infrared radiation by dust. If C _p is measured in g / m ³ and d in m, then σ _p , K _p and K _p are expressed in m ² / g.

In order to ensure that the intensities I _p and I _{p are} independent of the influence of changes in moisture, CO, CO ₂ , other gases in the smoke, as well as changes in the contents of sandstone С _ps and limestone С _and (i.e., eliminate the effect of redistribution of the contents of coal С _у , sandstone With _ps and limestone C _and dust at C _p C _y + C _ps + C _and const) it is necessary to choose the appropriate wavelength to determine C _p .

From the graphs shown in Fig.1 and Fig.2, it is seen that in the wavelength range of 7.6-8.4 μm there are no strong absorption bands of infrared radiation by the main gas components of the flue gases and in this wavelength range there are no strong absorption bands of IR radiation by moisture. In addition, in this wavelength range, the attenuation coefficients of infrared radiation of sandstone K _ps and limestone K _and dust are close to each other K _ps ≈ K _and . Therefore, in the wavelength range from 7.6 μm to 8.4 μm, the intensities of the transmitted I _p and forward scattered I _p IR radiation will depend only on the total dust content in the smoke C _p and will not depend on the redistribution of the contents of C _y , C _ps and C _and with C _p const.

From the graphs shown in Fig. 1 and Fig. 2, it is seen that in the wavelength range of IR radiation of 3.0-3.4 μm, there are no strong absorption bands of IR radiation by moisture and flue gases, the contents of which can vary greatly, carbon dioxide and carbon monoxide gases. The methane content in flue gases is negligible, so methane does not have a noticeable effect on the attenuation and scattering of infrared radiation. Therefore, the attenuation coefficients and scattering of infrared radiation in the wavelength range of 3.0-3.4 microns _{in a} K moisture, carbon monoxide and carbon K _g K _{to the} gases can be ignored, since they are not less than a hundred times smaller than the attenuation coefficients IR radiation by various dust components: K _at ≈ 0, K _g ≈ 0, K _p >> K _c, K _p >> K _g , K _p >> K _k , K _y >> K _c , K _y >> K _g , K _y >> K _to , K _ps >> K _to , K _ps >> K _g , K _ps >> K _to , K _and >> K _to , K _and >> K _g , K _and >> K _{to .}
From the graphs shown in figures 1 and 2, it is seen that in the wavelength range of 3.0-3.4 μm, the attenuation coefficients of infrared radiation of limestone and sandstone dust are approximately equal to each other K _and ≈ K _ps . In addition, in this wavelength range, the attenuation coefficients of infrared radiation by coal dust are almost three times different from the attenuation coefficients of infrared radiation by the components of rock dust (calcareous and sandstone).

From the graphs shown in figures 1 and 2, it can be seen that in the wavelength range of 4.1-4.5 μm there is a strong absorption band of infrared radiation with carbon dioxide CO ₂ , there are no strong absorption bands of infrared radiation with moisture and other flue gases, the content which in smoke can vary greatly. In this wavelength range attenuation factors IR sandstone K _ps and limestone dust _{K, and} approximately equal to each other and different from 2.6-fold attenuation of IR radiation coal dust.

From the graphs shown in figures 1 and 2, it is seen that in the wavelength range of 4.5-4.7 μm there is a strong absorption band of infrared radiation with carbon monoxide CO ₂ , there are no strong absorption bands of infrared radiation with moisture and other flue gases, the content which in smoke can vary greatly. In this wavelength range, the attenuation coefficients of infrared radiation of sandstone K _ps and limestone K _and dust are approximately equal to each other and 2.5 times different from the attenuation coefficient of infrared radiation by coal dust K _у .

Thus, in the wavelength range, radiation intensities depend only on the content of total dust With _p 7.6-8.4 microns. In the wavelength range of 3.0-3.4 μm, the intensities mainly depend on the contents of C _p and C _pores C _ps + C _and . In the wavelength range from 4.1 to 4.5 μm, the intensities depend on the content of carbon dioxide, coal and rock dust. In the wavelength range of 4.5-4.7 microns, intensities mainly depend on the content of carbon monoxide, coal and rock dust.

 From the graphs shown in figures 1 and 2, it is seen that in the wavelength range of 1.3-1.7 μm there are strong attenuation bands of IR radiation by moisture, there are no strong attenuation bands of IR radiation by flue gases, the contents of which in smoke can vary greatly . In this wavelength range, the attenuation coefficients of infrared radiation of sandstone and limestone dust are approximately equal to each other and almost 5 times different from the attenuation coefficient of infrared radiation of coal dust. Here, the intensities mainly depend on the moisture content, coal and rock dust in the smoke.

Thus, the wavelength ranges of 7.6-8.4 microns and 3.0-3.4 microns for the tasks of separate control of the total dust content in smoke С _p and control of the content of coal dust in smoke С _у are optimal: in the first wavelength range high-precision measurement is ensured C _n, a second high-precision measurement of C _in C C _n C _n C _long C _{and ps.} The wavelength ranges of 4.1-4.5 microns, 4.5-4.7 microns and 1.3-1.7 microns are optimal for high-precision measurement of the contents of carbon dioxide C _k , carbon monoxide C _g and moisture C _c , respectively since in these wavelength ranges the intensities depend respectively: on carbon dioxide, coal and rock dust; from carbon monoxide, coal and rock dust; from moisture, coal and rock dust.

From the dependences I _p f (C _p ) and I _p f ₁ (C _p ) shown in FIG. 3, it can be seen that with increasing C _{p, the} first intensity I _p exponentially decreases. With an increase in C _{p, the} intensity I _p increases in the range of C _p from 0 to C _pmax when (+ K _p C _pmax d) 1, i.e. when C _pmax (K _p d) ^-1 .

In this range of changes C _p from 0 to C _pmax (K _p d) ^{-1 the} value of the ratio of intensities
η _p [I _op + σ _p dC _p exr (- K _p dC _p )] [I _op x
x exp (-K _p dC _p )] ^-1 (3) grows smoothly with increasing C _p , as shown in figures 4 and 5. It can be seen that the dependence η _p f ₂ (C _p ) is more abrupt than the dependence I _p f (C _p ) or I _p f ₂ (C _p ). To estimate the gain to increase the S _o attitude sensitivity to the total dust content C _n as to the contents of coal dust C _in against the respective sensitivities in the past S _n, and the forward scattered S _p of infrared radiation in the registration respectively I _n and I _p evaluate the sensitivity themselves.

K_пd=const
(4) и не зависит от изменений С_п (или соответственно от С_у, С_г, С_к, С_в).The relative sensitivity to C _p (or C _y ) or to any other dust component of the intensity of transmitted infrared radiation I _p by the absolute change C _p from (I) is written as
S _p

K _p d = const
(4) and does not depend on changes in C _p (or, respectively, on C _y , C _g , C _k , C _c ).

(-K_пdC_п)](1-K_рdC_п)[I_ор+

p(-K_уdC_у)](1-K_руdC_у)[I_ору+
(5)
Относительная чувствительность отношения η_п или η_у к С_п или к С_уиз (3) запишется в виде
S_o (∂η_п/∂ С_п) η_п ^-1 I_о ^-1[I_opK_пdC_п eхр x x(-K_пdС_п) + C_п σ_п d eхр (-K_рdC_п + K_пdC_п)](1-K_рdC_п + К_пdC_п)I_оп eхр (-K_пdC_п) [I_oр + σ_п dC_п x x eхр (- K_рdC_п)] ^-1,
S_oy (∂η_у/∂C_y)η_у ^-1= I_oу ^-1[I_oруK_уdC_yeхр(-K_уdC_y)+σ_уdC_yeхр (-K_pуdC_y +
K_уdC_у)] (1-K_pydC_y + K_ydC_y) I_oу ехр (-K_ydC_y)[I_opу+σ_уdC_уехр (-K_pуdC_у)] ^-1
(6)
Аналогично (4), (5) и (6) запишутся и относительные чувствительности прошедшего, и рассеянного вперед ИК-излучения или отношения интенсивностей к С_г, С_к или к С_в.The relative sensitivity to C _{p of the} intensity of forward-scattered IR radiation I _p by the absolute change in the content of C _p or C _y from (2) can be written as

(-K _p dC _p )] (1-K _p dC _p ) [I _op +

p (-K _y dC _y )] (1-K _ru dC _y ) [I _yo +
(5)
The relative sensitivity of the ratio η _p or η _y to C _p or to C _y from (3) can be written as
S _o (∂η _p / ∂ C _p ) η _p ^-1 I _o ^-1 [I _op K _p dC _p exp xx (-K _p dC _p ) + C _p σ _p d exp (-K _p dC _p + K _p dC _p )] (1-K _p dC _p + K _p dC _p ) I _op exp (-K _p dC _p ) [ _Iop + σ _p dC _p xx exp (- K _p dC _p )] ^-1 ,
S _oy (∂η _y / ∂C _y) η _y ^-1 = I _Ou ^-1 [I _oru dC _y K _y ehr (-K _y dC _y) + σ _y dC _y ehr (-K _pN dC _y +
K _y dC _y )] (1-K _py dC _y + K _y dC _y ) I _oy exp (-K _y dC _y ) [I _op + σ _y dC _y exp (-K _y dC _y )] ^-1
(6)
Similarly to (4), (5) and (6) are written, and the relative sensitivity of the past, and forward-scattered radiation or IR intensity ratio to C _r, C _k or k _C.

Dependency Graphs S _p | S _p | and s _about | from C _p are shown in Fig.6. It is seen that the relative sensitivity to C _{p of the} value of the ratio S _o within the concentration range 0 <C _p <C _pmax is the greatest.

An analysis of formula (3) shows that the same relative changes in the intensities I _p and I _p (no matter how many times they simultaneously change) do not lead to the slightest change in the ratio η _p . Therefore, the magnitude of the intensity ratio will not change in any way either from a change in the intensities from the radiation source, or from pollution of the source or photodetector windows, or from changes in the temperature of the exhaust gases, since any of these three causes leads to identical relative changes in both intensities I _p and I _p .

The dependence η _p f ₂ (C _p ) according to formula (3) is a transcendental equation from which C _p is not explicitly expressed, which is inconvenient for measurements, since it is necessary to resort to complex and cumbersome methods of numerical solution of equation (3) with respect to With _p . As can be seen from the graphs in figure 4 and figure 5, the dependence η _p f ₂ (C _p ) by the formula (3) can be approximated by the expression
η _p a _p C _p ² + b _p C _p ,
η _y a _y C _y ² + b _y C _y a _p 'C _p ² + b _p ' C _p -a _y (C _p -C _pore ) ² + b _y (C _p -C _pore ) a _p 'C _p ² + b _p 'C _p ,
η _to a _to C _to ² + b _to C _to a _y 'C _to ² + b _y ' C _y
and _pores having a _{pore pore} ² + b C _long C _long C C _{y n,}
η _g a _g C _g ² + b _g C _g a _y '' C _y ² + b``C _{y-a pore} 'C _pore ² + b _pore ' C _pore ,
η _in a _in C _in ² + b _in C _in a _y '''C _y ² + b _y ''' C _{y-a pore} '' C _pore ² + b _pore '' C _pore .

(7) In the general case, the dependences (7) are quadratic parabolas having an ascending branch, a gently sloping maximum, and a falling branch. The middle of a gently sloping maximum is achieved when the derivative of the ratio with respect to the corresponding content is equal to zero
∂η _p / ∂ C _p 2a _p C _p '+ b _p 0,
∂η _y / ∂ C _y 2a _y C _y '+ b _y 0,
∂η _c / ∂ C _to 2a _to C _to '+ b _to 0,
∂η _g / ∂ С _g 2а _g С _g '+ b _g 0,
∂η _in / ∂ C _at 2 a _in C _at 'b _at 0, (8) which corresponds to the contents of C _p ' b _p (2a _p ) ^-1 , C _y 'b _y (2a _y ) ^-1 , C _g ' b _g (2a _g ) ^-1 , C _to '= b _to (2a _to ) ^-1 , C _to ' b _to (2a _to ) ^-1 . The approximation errors at the working section do not exceed 0.2% of the measured contents in the entire range of their changes from 0 to 0.9 C _p '(or, respectively, 0.9 C _y ', 0.9 C _g ', 0.9 C _to 'or 0.9 C _in '). Therefore, the approximating curve is considered acceptable even by the most stringent criteria.

-b_п±

C_у,1,2=(-2a_y)

-b_у ±

,
C_к,1,2=(-2a_к)

-b_к±

,
C_г,1,2=(-2a_г)

-b_г±

,
C_в,1,2=(-2a_в)

-b_в±

. (9)
Меньшие из значений С_п1, C_у1, С_г1, С_к1 или С_в1 находятся на рабочих участках парабол (7), а большие значения С_п2, С_у2, С_г2, С_к2 или С_в2находятся на падающих ветвях парабол. Так как b_п>

b_у>

b_к>

b_г>

b_в>

то для обеспечения C_п < b_п(2а_п)^-1, С_у < b_у (2а_у)^-1, С_г < b_г (2а_г)^-1 С_к< b_к (2а_к)^-1, С_в < b_в (2а_в)^-1 в формулах (9) перед корнем нужно брать знак (+), а неизвестное содержание соответствующего компонента в дыме определять по однозначным формулам
C_п1=(-2a_п)

-b_п+

,
C_у1=(-2a_у)

-b_у+

,
C_к1=(-2a_к)

-b_к+

C_г1=(-2a_г)

-b_г+

C_в1=(-2a_в)

-b_в+

. (10)
Для определения значений градуировочных коэффициентов уравнений (7) можно пользоваться любым методом градуировки. Изменение метода градуировки лишь изменит ее трудоемкость, но никак не повлияет на значения коэффициентов. Один из приемлемых методов градуировки описан в книге Онищенко А.М. Оптимизация приборов для контроля состава веществ М. Машиностроение, 1990, с. 18-29, с. 155-156, с. 251-256.From the approximating equations (7), one can obtain two values of the corresponding content
C _{p, 1,2} = (- 2a _p )

-b _p ±

C _{y, 1,2} = (- 2a _y )

-b _y ±

,
C _{k, 1,2} = (- 2a _k )

-b _to ±

,
C _{g, 1.2} = (- 2a _g )

-b _g ±

,
C _{in, 1.2} = (- 2a _in )

-b _to ±

. (nine)
The smaller values of С _п1 , С _у1 , С _г1 , С _к1 or С _в1 are located on the working sections of the parabolas (7), and the larger values С _п2 , С _у2 , С _г2 , С _к2 or С _B2 are located on the falling branches of the parabolas. Since b _p >

b _y >

b _to >

b _g >

b _in >

then to ensure C _p <b _p (2a _p ) ^-1 , C _y <b _y (2a _y ) ^-1 , C _g <b _g (2a _g ) ^-1 C _k <b _k (2a _k ) ^-1 , _C <b _{to (2a)} ^-1 in the formula (9) must be taken before the root sign (+), and the unknown content of the respective components in the smoke uniquely determined by the formulas
C _p1 = (- 2a _p )

-b _n +

,
C _y1 = (- 2a _y )

-b _y +

,
C _k1 = (- 2a _k )

-b _to +

C _g1 = (- 2a _g )

-b _g +

C _in1 = (- 2a _in )

-b _to +

. (10)
To determine the values of the calibration coefficients of equations (7), you can use any calibration method. Changing the calibration method will only change its complexity, but will not affect the values of the coefficients. One of the acceptable calibration methods is described in the book of A. Onishchenko. Optimization of devices for controlling the composition of substances M. Mechanical Engineering, 1990, p. 18-29, p. 155-156, p. 251-256.

 The device for automatic control of the composition of the exhaust gases shown in Fig. 7 comprises an infrared radiation source 1 with a collimator 2 and a photodetector 3 with a modulator representing an obturator 4 (modulating diaphragm) installed opposite each other on opposite sides of a controlled volume of gas of thickness d fixed on the shaft 5 of the stepper motor 6; an indication and registration unit 7, five adjusters 8, 9, 10, 11 and 12, a difference meter 13, three ratio meters 14, 15 and 16, series-connected difference meter 17 and a ratio meter 18.

 The device is equipped with an additional photodetector 19, a computing unit 20, a ratio meter 21, three difference meters 22, 23 and 24, ten circuits from a series-connected amplifier 25, 26, 27, 28, 29, 30, 31, 32, 33 or 34 and a strip filter 35, 36, 37, 38, 39, 40, 41, 42, 43 or 44.

 An additional photodetector 19 is installed outside the collimated infrared beam (shown by solid lines with arrows in Fig. 7) behind the modulator 4. Both photodetectors 3 and 19 are made multi-band at the wavelengths of the detected radiation 1.3-1.7 μm, 3.0- 3.4 microns, 4.1-4.5 microns, 4.5-4.7 microns and 7.6-8.4 microns. The outputs of the photodetectors 3 and 19 are connected to the inputs of the amplifiers 25, 26, 27, 28, 29, 30, 31, 32, 33 and 34. The outputs of the five band-pass filters 35, 36, 37, 38 and 39 from the outputs of the additional photodetector 19 are connected to the first the inputs of the difference meters 13, 22, 23, 17 and 24, to the second inputs of which the outputs of the adjusters 8, 9, 10, 11 and 12 are connected. The outputs of the difference meters 13, 22, 23, 17 and 24 are connected to the first inputs of the meters 14, 15 , 16, 18 and 21, to the second inputs of which the outputs of the five bandpass filters 44, 43, 42, 41 and 40 are connected from the outputs of the photodetector 3. The outputs of the five relationship meters 14, 15, 16, 18 and 21 oedineny to the inputs of computational unit 20, whose output is connected to the input unit and the indicating registration.

 The operation of the device for automatic control of the composition of the exhaust gases is as follows.

 The collimated infrared radiation flux is generated by source 1 and collimator 2. As source 1, for example, an incandescent lamp with a germanium output window can be used, which is drilled to a wavelength range of 1.3–8.4 μm. As a collimator, a plate with an aperture can be used, and the plate must be made of a material opaque to the wavelength range 1.3–8.4 μm, for example, of any metal.

 When passing through a controlled volume of flue gas with a thickness, the infrared radiation flux is attenuated according to formula (1). The five outputs of the photodetector 3 generate signals proportional to the intensities of the transmitted infrared radiation according to formulas 1. These signals are amplified by amplifiers 30, 31, 32, 33 and 34, respectively, and are tuned out from the noise in the bandpass filters 40, 41, 42, 43 and 44, which are tuned the modulation frequency of the infrared radiation stream obturator 4.

The flux of forward-scattered infrared radiation also passes through the controlled volume of the mine atmosphere (first pass through the smoke quanta of infrared radiation from source 1 to the corresponding scattering centers, and then through the smoke pass quanta of infrared radiation that have undergone at least one act of scattering and changed the direction of the initial propagation so that after scattering they go in the direction of the additional photodetector 19). The intensities of forward-scattered IR radiation to an additional photodetector 19 in the corresponding wavelength ranges are determined by formulas similar to (2). At the five outputs of the additional photodetector 19, signals are generated proportional to the intensities of the infrared radiation scattered forward according to formulas (2). These signals are amplified by amplifiers 25, 26, 27, 28, and 29, respectively, and are tuned out from noise in bandpass filters 35, 36, 37, 38, and 39, which are tuned to the modulation frequency of the infrared radiation stream by the obturator 4. These signals are then fed to the first inputs difference meters 13, 22, 23, 17 and 24. The second inputs of these difference meters from setters 8, 9, 10, 11 and 12 respectively receive signals that are numerically equal to the intensities of the infrared radiation scattered forward at zero values of the corresponding contents, i.e. _E. , respectively, the signals I _op , I _opu , I _org , I _ork and I _{op c} . The outputs of the difference meters 13, 22, 23, 17 and 24 as a result of the corresponding signals are generated:
I _p 'σ _n d C ehr _n (-K _p dC _n), I _pB' σ _in dC _in ehr x
x (-K _pv dC _c ),
I _pN 'σ _y dC _y exp (-K _{y py} dC)
I _pk 'σ _to dC _to exp (-K _pk dC _to ),
I _pg 'σ _g dC _g exp (-K _p dC _g ). (eleven)
These signals are fed to the first inputs of the relationship meters 14, 15, 16, 18 and 21, to the second inputs of which signals I _p , I _y , I _g , I _k and I _c , respectively, which are formed at the outputs of the bandpass filters 44, 43, 42, 41 and 40.

As a result, at the outputs of the relationship meters 14, 15, 16, 18, and 21, signals corresponding to signals according to (3), but differing from them by the absence of free terms in the signals about the intensities of forward-scattered IR radiation, are formed, respectively, according to the formulas: η _p ' dC = σ _{n n} ehr (-K _o dC _n) [I _OP ehr (-K _n dC _n)] ^-1, η _{y '=} σ _{y y} ehr dC (-K _pN dC _y) [I _Ou ehr (- K _y dC _y ) ^-1 , η _{k '} = σ _to dC _k exp (-K _pk dC _k )] [I _ok exp (-K _to dC _k )] ^-1 , η _g ' = σ _g dC _g exp ( -K _rg dC ₁ )] [I _og exp (-K _g dC _g )] ^-1 , η _in '= σ _in dC _in exp (-K _pv dC _in )] [I _o exp (-K _in dC _in ) ] ^-1 .

(12)
These signals from the relationship meters are fed to the inputs of the computing unit 20. The computing unit in the process of calibrating the device is filled with the values of the coefficients of the calibration parabolas according to equations (7). According to the five signals received at the inputs of the computing unit 20 and the calibration coefficients of the parabolas according to equations (7), the computing unit 20 first determines the total dust content C _p in the exhaust gases according to the first equation of the system (7) according to the first formula of the system (10). After that, similarly, knowing the calibration coefficients and the value of C _p , according to the second formula of the system of equations (10), the computing unit determines the content of coal dust in the exhaust gases C _y . From the known values of C _p and C _pore C _p C _at C _ps + C _{and the} known calibration coefficients of the parabola according to equations (7), the computing unit according to the third, fourth and fifth equations of system (10) determines the contents of C _to , C _g and C, respectively _in the exhaust gas.

The values of C _p , C _y , C _g , C _k and C _c calculated by the computing unit 20 go to block 7, where they are displayed and recorded directly in units of the corresponding contents.

 The formation at the outputs of the meters of the difference 13, 22, 23, 17 and 24 of the signals according to formulas (11) leads to the fact that all calibration parabolas according to equations (7) start from zero and are good approximations of equations (12). As a result, the accuracy of measurements of the contents of the components of the exhaust gases at the edges of the measurement ranges increases.

PRI me R implementation of the device. The total dust content in the exhaust gases С _p and the content of coal dust С _{у were} determined within the limits of the change of contents from 0 to 340 g / m ³ with an average square error of not more than 0.5% of the measured content. The content of carbon monoxide and carbon dioxide was determined in the range of changes in the contents from 0 to 20% by volume with a mean square error of not more than 0.6% of the measured content. The relative humidity of the exhaust gases was determined in the range of changes from 0 to 100% with a mean square error of not more than 0.6% of the measured humidity. Such a high accuracy of measurements of C _p , C _y , C _g , C _k and C _c does not provide the known methods and devices for automatic continuous monitoring of the composition of the exhaust gases.

To determine the technical and economic efficiency of the device as a basic object, we will take an optical-acoustic gas analyzer of the GOA-4 type [3] The main technical advantages of the device according to this invention compared to the GOA-4 gas analyzer are:
1) expanded functionality by measuring the contents of C _p , C _y , C _in , C _g , 2) the effect of changes in the intensity of the source due to changes in the supply voltage of the source (due to changes in the resistance of the filament and other reasons) is reduced to zero , 3) the effect of contamination of the source and photodetector windows is reduced to zero, 4) the effect of the temperature of the exhaust gases is reduced to zero (since any temperature changes by the same number of times change the intensity of transmitted and forward-scattered IR radiation at any of five wavelengths), 5 ) at The sensitivity to the measured contents of the components of the exhaust gases was increased, 6) the cost of one component measurement was reduced, 7) the measurement errors were reduced from 10-4% to 0.5-0.6% 8) the device was simplified by eliminating thermostating and purging the photodetectors with nitrogen under pressure .

Claims (1)

 DEVICE FOR AUTOMATIC CONTROL OF THE EMPLOYED GAS COMPOSITION, comprising an infrared radiation source with a collimator and a first photodetector with a modulator mounted on the shaft, an indication and recording unit, the first fifth adjusters, the first subtractor, the first - the third dividers, connected in series with the output of the first subtractor connected to the first input of the first divider of relations, characterized in that it is provided with a second photo a receiver, a computing unit, a fourth fifth divider, a second fourth subtractor and ten circuits, each of which consists of a series-connected amplifier and a band-pass filter, the second photodetector installed outside the collimated infrared beam on the other side of the modulator shaft, each photodetector is made five-band for length waves of detected radiation, respectively, at 1.3, 1.7, 3.0, 3.4, 4.1, 4.5, 4.5 4.7 and 7.6 8.4 microns, while the first fifth outputs of the second photodetector are connected to entry by the first fifth circuits, respectively, the first fifth outputs of the first photodetector are also connected to the inputs of the sixth tenth circuit, respectively, the outputs of the first fifth circuit are connected to the first inputs of the first and fifth subtracters, the second inputs of which are connected respectively to the outputs of the first fifth adjusters, and the outputs of the second fifth subtractors connected respectively to the first inputs of the second fifth dividers, the outputs of the tenth to sixth circuits are connected to the second inputs of the first fifth dividers respectively, the outputs of the first the fifth fifth dividers are connected respectively to the first fifth inputs of the computing unit, the output of which is connected to the input of the display and registration unit.

Images