SU981819A1 - Method of automatic determining of heat exchange apparatus shut-down time moment - Google Patents

Description

The invention relates to methods for assessing the technical condition of heat exchangers and can be used in chemical, oil and power engineering to determine the need for washing ⁵ and cleaning, in particular shell-and-tube heat exchangers.

I Known methods for automatically determining the stopping time of the heat-exchange apparatus for washing and cleaning 'heating surfaces by measuring ·. ” flow rate of working media, their temperatures at the inlet to the apparatus and determining the indirect parameter. characterizing the moment ₁₅ stop heat exchanger [YJ.

However, this method, allowing the verification of serviceability, operability, and functioning, does not make it possible to determine the specific malfunctions — * 20 features in a multi-pass device, i.e. does not allow the search for defects.

Deterioration of the technical condition of the heat exchanger can be caused by several malfunctions, and all of them can develop simultaneously and in different specific operating conditions *, each of them will be characterized by an individual degree of development ..

Deterioration can be caused by an infinitely large number of combinations of different degrees of development of individual malfunctions, but for a certain degree of deterioration of the state of the apparatus, it is impossible to judge which malfunctions occur in a particular case and what is their degree of development.

The purpose of the invention is the technical diagnosis of faults in a multi-way apparatus without disassembling the latter.

The goal is achieved by the fact that according to; a way to automatically detect my | the stopping time of the heat exchanger apparatus for washing, and cleaning heating surfaces by measuring the flow rate of workers, media, their '. “temperatures at the inlet to the apparatus and determining the indirect parameter characterizing the moment the heat exchanger stops 3 981819 4 of the exchange apparatus, additionally measure the current values of pressure drops of one of the media in the apparatus and at the first * stroke, they are compared with critical values and the comparison signals are used as an indirect parameter.

The drawing shows the installation that implements the proposed method. \

The installation comprises a heat exchanger 1, a sensor 2 for a total pressure drop -> 0 of singing Д Р on the device 1, a sensor 3 for a pressure drop Δ на ₄ at the first stroke of the device 1, a sensor 4 for the temperature of the cooling medium at the inlet to the device 1, date- '; chik 5 flow rate G of the cooling medium, sensor ^{, 5} chik 6 temperature £ of the cooled medium at the outlet of the apparatus 1, sensor 7 flow Q of the cooled medium, temperature sensor 8 t cooled medium? at the entrance to the apparatus 1, the computing device 9, 20 generates critical values, the secondary showing device 10, the comparison element 11, the computing device 12, which determines the degree of development of faults, power amplifier 13, ²⁵ signaling unit 14. ι

PRI me R. Using sensors 2 to 8, respectively measure the total pressure drop of the cooling medium in the apparatus 1, the pressure drop of the cooling medium, M> the medium during the course of the apparatus 1, pace] | the cooled medium at the outlet πφ of the apparatus 1, the flow rate of the cooled medium at the inlet to the apparatus 1, the temperature of the cooled medium at the inlet to the apparatus 1. Then, using the computing device 9, critical pressure drops are determined from the measured 40 temperature values and the costs of the cooling and cooled media at the inlet to the apparatus 1.

, ι.

Using sensors 2 and 3, the current pressure drop determined by the cooling conductive medium ⁴³ in the apparatus and during the first tube space. After that, the current values of the measured parameters are compared with their critical values using the comparison element 11. On a ⁵⁰ basis of the analysis of the signals of element 11, a technological diagnosis of faults is carried out without stopping and dismantling the heat exchanger.

Diagnostics of technical malfunctions is carried out on the basis of the analysis of the transfer function of the technical condition of the heat exchanger, characterized by an indicator calculated by the formula where Ai _C p is the temperature change of one of the media in the apparatus, i.e., the temperature difference of this medium at the inlet to the apparatus 1 and exit from it;

difference in working media at the inlet to the apparatus 1.

Having in this mode the changes of the state indicator of the apparatus and two pressure drops calculated by the known dependencies, they solve the system of equations connecting the state indicator with malfunctions and determine the degree of development of the latter. In general, the system of regression equations can be written as follows δί _Μ1 Η (π, О, 3) δΔΡ _απ = ί (П, О, 3)

8pP _x = f (P, o, 3) _? where is the change in temperature of one of the media at the outlet of the apparatus;

5% - change in the total pressure drop across the apparatus;

8P _X - change in pressure drop in the first stroke;

P - parameter characterizing the degree of destruction of the septum;

O is a parameter characterizing the thickness of deposits;

B. - a parameter characterizing the number of curled pipes of the first stroke.

The reference values of the degrees of faults, P, O, and 3 are also determined by the regression equations, but empirically.

The application of the proposed method in comparison with the known allows for the planned technical diagnosis of multi-pass heat exchangers, as well as the order and timing of their maintenance.

Claims (1)

1. USSR author's certificate No. 672473, cl. V 28 F 27 / GS, 1979. Vhladavpa Wednesday O llf