SU479026A1 - The method of determining the amount of the target component in the stream - Google Patents

Description

one

The invention relates to the field of chemistry and will be used for the calculation of the technical and economic parameters of technological devices of chemical production.

A known method for determining the amount of a target component in a stream of a gaseous or liquid product with a time-varying flow rate and chemical composition, at which constant samples are taken periodically from the flow And the flow rate is measured. In the selected samples, the concentration of the target component is measured, the results of flow and concentration measurements are recorded and, after a specified time interval, the amount of the target component is determined as the sum of private products of the measured concentrations and the product flow rates at the time of sampling.

The known method has low accuracy due to the fact that the time interval between the individual measurements of the concentrations of the key component is very long. The concentration measurement is carried out by a quality analyzer, such as a chromatograph, which is a batch device. The duration of a single sample analysis cycle with an analyzer to determine the concentration of a key component in a product stream with a complex composition can last 1-1.5 hours and therefore

when using one analyzer, the minimum time interval between adjacent measurements of the mi-concentration by the analyzer has the same duration as the analysis cycle of a single sample. Such rare measurements of the concentration of a key component in a stream introduce significant error in the results of determining its quantity.

The aim of the invention is to improve the accuracy of determining the amount of the target component in a stream of gaseous or liquid product.

This goal is achieved by the fact that in each

an inert diluent is taken of the product being sampled, depending on the consumption of the product during sampling, constant samples are taken from the resulting mixture and accumulated during a predetermined interval

time with subsequent measurement in the accumulated mixture of the concentration of the target component proportional to the amount of this component in the stream for a specified time interval.

The drawing shows a diagram of one of the possible variants of a device that implements the proposed method for determining the amount of a target component in a fluid flow.

The working cavity of the dispenser 1 is connected via a valve 2 and 3 with the technological device 4, the replaceable or daily output of which is determined by the key component, and through the valve 5 with a mixer 6. The tank 7 filled with liquid is an inert diluent, through the choke 8 and valve 9 is also connected to mixer 6. The output of mixer 6 through valve 10 is connected to the discharge line, and through valve I to the working cavity of the dispenser 12, which is connected through valve 13 to storage tank 14 connected to valve 15 through the discharge line. The input of the flow meter 16, which continuously measures the product flow rate, is connected to the process unit 4, and the output is connected to the input of the separating device 17. The output of the separating device 17 is connected to the control circuit of the clalan 9. The control circuits of the valves 2, 3 and 5, the metering drive 1 and the separating device 17 are connected to the output P of the command device 18, the clalan 11 and the drive of the dispenser 12 with the output P, and the valves 10-13 with the output P. The tank 7 is connected to a source of gas with a constant pressure. The following methods are used to determine the amount of the target component. In the initial position, the signals at the outputs of the command device 18 have zero values (P P 0). Valves 2 and 3 are open, and valves 5, 9, 10, And, and 13 are closed. Through the working cavity of the dispenser 1, the liquid product produced by unit 4 flows. The filling container 14 is emptied and the valve 15 is closed. The cycle of preparation and input of each sample into the junction box 14 consists of two successive stages. The first stage involves the selection of a constant sample from the product stream produced by apparatus 4, and the addition of an inert diluent to the sample in an amount inversely proportional to the consumption of the product at the time of sampling. When forming the signal P i at the output of the command device 18, valves 2, 3 and 5 are switched and commands are issued to turn on the drive of the dispenser 1 and the divider device 17. Dispenser 1 is disconnected from technological device 4 and connected to mixer b, where it will be pushed out of dispenser 1 A sampled sample of a product of constant volume, the concentration of the target component C in which is equal to the current concentration of this component in the stream. The amount of the target component g received from the dispenser 1B, mixer 6, is: A, G i Aio g where: Ki is a constant value. At the same time, a single signal is formed at the output of the dividing device 17 with a duration inversely proportional to the current value of the product flow rate in the flow Q; . This signal will open the clalan 9, and an inert diluent will flow from the tank 7 through the choke 8 to the mixer 6, the flow rate of which will be constant due to the constant pressure drop across the choke 8 and its conductivity. The opening time of valve 9 is equal to the duration of the signal at the output of the divider device 17, as a result of which the amount of inert diluent G is; coming from the tank 7 to the mixer 6 will be proportional to the duration of the signal on the output of the divider device 17, and therefore inversely proportional to the current value of the product flow in the flow Q; , i.e., 0, -, (2) where: Kg is a constant value. After mixing the sample of the product with an inert diluent, the concentration of the target component C in mixer 6, taking into account expressions (1) and (2), will be: C - K, C, Q, GI where: Cs is a constant value. Thus, the concentration of the target component C in the mixer 6 is directly proportional to the product of the current flow rates of the product Q, - and the concentration of the target component C; in this stream. When a single signal P disappears from the output of the command device 18, the valves 2, 3, and 5 return to their original position and the working cavity of the dispenser 1 is again connected to the technological device 4. The second stage involves the selection of a constant nro, from the mixture of the product and the dilute diluent and transfer of this sample into the accumulative tank 14. When the signal is given, the actuator of the dispenser 12 is turned on and the valve I is opened. The working cavity of the dispenser 12 is filled with a mixture of product and an inert diluent from mixer 6. Next, the signal P is removed (/ - 0) and a signal is given, with valves 10 and 13 opening and valve 11 closing. The mixture left with in the mixer 6 after filling the dispenser 12 is discharged into the drain, and the mixture from the working cavity of the dispenser 12 is completely displaced into the storage tank 14. The amount of key component g-, which will enter the storage tank 14 taking into account the constant amount of the mixture G entered by the dispenser 12, is equal to: g- K, C, Q. where: / (4 CsO - constant value.

The relation (4) shows that the quantity of the target component gl, arriving B capacity 14 from the dispenser 12, in one portion of the sample is proportional to the product of the current primary consumption of the product Q; and the concentration of the target component C.

After the removal of the signal (), the valves 10 and 13 return to the initial position, and the training cycle CI1CL and the introduction of one sample portion into the additional container 14 is completed.

The frequency of sampling from the stream is determined empirically depending on the dynamic properties of the product stream produced by the process unit 4 and is set by the command device 18. A predetermined time interval (shift, day) will be transferred to the storage tank 14 of the mixture from the product and the inert diluent .

The average concentration of the key component in the storage tank 14 is:

g

(five)

Lg

S g

OR taking into account the ratio (4)

c; p

(sS C, .Q ,.

to,

  ,

constant value. one

As follows from relation (6), the average concentration C of the target component in the storage tank 14 is proportional to the sum of the private products of the current values, the flow rate of the product Q, and the concentration of the target component C; in him.

After a predetermined time interval has elapsed, the sample is analyzed from storage tank 14. The concentration of the target component C obtained as a result of the analysis is proportional to its quantity, i.e., the development of the apparatus along the key component for a given time interval.

After sampling for analysis, the mixture from storage tank 14 through valve 15 is drained into the drain.

The accuracy of determining the amount of the target component in the proposed method does not depend on the duration of the analysis of samples on the quality analyzer, since the analysis is performed only once after a specified time interval has elapsed. The method allows for a high frequency of selection of the nrob and therefore the number of target komioneita can be determined with high accuracy.

Subject invention

A method for determining the amount of a target component in a gaseous or liquid product stream with a variable flow rate and chemical composition by taking constant samples from the flow and measuring its flow, characterized in that, in order to increase the determination accuracy, to add to each sample of the product

inert diluent depending on the amount of product in the sample, constant samples are taken from the resulting mixture and accumulated for a specified time interval with subsequent measurement in the accumulated mixture of the concentration of the target component proportional to the amount of this component in the stream for a given time interval.