RU162551U1 - DEVICE FOR DETERMINING THE FULL AND RESIDUAL RESOURCE OF STEAM HEATER PIPES FROM AUSTENITIC STEEL - Google Patents

Abstract

A device for determining the total and residual life of steam superheater pipes made of austenitic steel, comprising: a processor unit with terminal sockets for connecting a remote ferritometric tip and a remote ultrasonic thickness gauge; a keyboard connected to the indicated processor unit for entering the necessary additional values, as well as necessary measurement data using regular measuring power plant means and a display for visualizing input and output data; moreover, the specified processor The unit includes: a processor unit for determining the equivalent operating temperature of the outer surface of the superheater pipes according to the measurements using the specified remote ferritometric tip of the mass-average concentration of ferrite phase in the metal on the outer surface of the superheater and using a standard oxygen meter of the concentration of oxygen in flue gases, in accordance with the ratio: where T is the equivalent temperature, K; c is the mass-average concentration of the ferrite phase in the metal on the outer surface of the superheater pipes,%; c - the average value of the oxygen concentration in the gas medium washing the superheater, kg / m; R = 8.314 J / (mol · K) is the universal gas constant; A, B, C are experimentally determined constants depending on the grade of austenitic steel; a processor unit for determining the reduced mechanical stress in the metal of superheater pipes according to the measurement data using the specified external ultrasonic thickness gauge of the residual pipe wall thickness and the known initial value n

Description

Technical field

The utility model relates to the field of power engineering and can be used in thermal power plants to monitor the strength of superheater pipes made of austenitic steels.

State of the art

Steam superheater pipes of modern steam boilers of thermal power plants are exposed to high temperatures and pressures, and therefore are made of heat-resistant austenitic steels.

Known magnetic ferritometer for assessing the temperature of steam superheater boiler tubes made of austenitic steels (RU 2458379, G01N 27/72, 2012 [1]). This device allows you to determine one of the important characteristics of the strength state of a superheater pipe, but far from sufficient for a correct assessment of its full and residual life.

Ultrasonic thickness gauges are known that make it possible to determine the residual wall thickness of an activated steam superheater pipe (GOST 28702-90. Non-destructive testing. Ultrasonic thickness gauges. General technical requirements [2]). This value is also one of the important, but insufficient characteristics for the correct assessment of these resources.

A known calculation method for determining the residual life of superheater pipes by a number of measured characteristics, including data from metallographic studies of cut pipe samples, and experimentally found mathematical relationships for a specific austenitic steel (Method for determining the residual resource of superheaters from steel DI59 / Bogachev V.A. et al. / / Electric stations, 2015, No. 5, pp. 16-20 [3]).

The study of the prior art did not reveal information about the devices for determining the total and residual life of superheater pipes made of austenitic steel. Thus, according to the applicant, a prototype of the claimed utility model is missing.

Utility Model Disclosure

The objective of the utility model is an operative reliable assessment of the total and residual life of superheater pipes with the exception of destructive testing methods, and the technical result is the creation of a device capable of making the necessary measurements using non-destructive testing methods, to memorize the data of these measurements and to promptly give the acceptable and full values of the total and residual resource of superheater austenitic steel pipes.

The solution of this problem by achieving the specified technical result is ensured by the fact that

A device was created for determining the total and residual life of superheater pipes made of austenitic steel, containing:

a processor unit with terminal sockets for connecting a remote ferrite tip and a remote ultrasonic thickness gauge;

a keyboard connected to the indicated processor unit for inputting the necessary additional values, as well as data of necessary measurements with the standard measuring means of the power station and a display for visualizing input and output data;

moreover, the specified processor unit includes:

a processor unit for determining the equivalent operating temperature of the outer surface of the superheater pipes according to measurements using the specified remote ferritometric tip of the mass-average concentration of ferrite phase in the metal on the outer surface of the superheater and using a standard oxygen meter for the concentration of oxygen in flue gases, in accordance with the ratio:

where T _equiv - equivalent temperature, K; with _f - the mass-average concentration of the ferritic phase in the metal on the outer surface of the superheater pipes,%; with _O - the average value of the oxygen concentration in the gas medium washing the superheater, kg / m ³ ; R = 8.314 J / (mol · K) is the universal gas constant; A, B, C - experimentally determined constants depending on the grade of austenitic steel;

a processor unit for determining the reduced mechanical stress in the metal of superheater pipes according to the measurement data using the specified external ultrasonic thickness gauge of the residual pipe wall thickness and the known initial value of the nominal internal diameter of these pipes, as well as the known value of the excess steam pressure at the entrance to them, in accordance with the ratio :

where σ is the reduced stress in the metal of superheater pipes, MPa; p is the excess steam pressure at the entrance to the superheater pipes in the basic mode of operation according to the boiler passport, MPa; d _n - initial nominal internal diameter of superheater pipes according to the boiler passport, mm; s _ost - residual wall thickness of the superheater pipe, mm;

a determinant of the current time from the moment the start of operation of the controlled steam superheater pipes;

processor node to determine:

the full resource of these superheater pipes in accordance with the ratio:

where τ _p - the full resource of superheater pipes, h;

E, F, G - experimentally determined constants, depending on the grade of austenitic steel; K _s - safety factor;

used share of the specified full resource in accordance with the ratio:

where τ _e is the current time since the start of operation of controlled superheater pipes, h;

share of residual life in accordance with the ratio:

and the residual life of these superheater pipes in accordance with the ratios:

where τ _ost - residual life of reliable operation of superheater pipes, h

A causal relationship between the totality of the essential features of a utility model and the specified technical result is as follows:

The presence of a processor unit with terminal sockets for connecting a remote ferrite tip and a remote ultrasonic thickness gauge allows you to measure and enter data into the device to determine the equivalent operating temperature of the outer surface of the superheater pipes and the residual wall thickness of the superheater pipe, to determine the reduced mechanical stress in the metal of these pipes.

The presence of the keyboard allows you to enter into the processor unit of the device the necessary additional values obtained from the standard measuring tools of the power station or known from the passport data and other information sources.

The presence of separate processor units for the production of intermediate and final calculations according to given mathematical relationships allows us to simplify the device due to its individualization with the exception of the need to use complex universal processors.

Definition of basic concepts

Ferritometer is a device for measuring the concentration of the ferrite phase on the outer surface of superheater pipes [1].

Ferrite phase - the content of ferrite in carbon (ferrite steels), as well as in the surface layer of superheater pipes from austenitic steels due to the formation of such a layer during operation [1].

Ferritometric tip - a sensitive element (sensor) of a ferritometer

[http://www.ntcexpert.ru/md/ferritometrv/769-ferritometr-mf51nc]

Equivalent temperature of the outer surface of superheater pipes - design temperature equivalent to the actual operating temperature, causing similar residual changes in the outer layer of the specified surface.

Therefore, the reduced stress is the stress of such a uniaxial stress state, which, according to the condition of transition to a plastic state, corresponds to this complex stress state. http://www.ktovdome.ru/58/369/103/11148.html

Brief Description of the Drawing

The drawing shows a block diagram of a device according to a utility model.

Legend

VUZT - remote ultrasonic thickness gauge;

VFN - remote ferritometric tip;

ITV - current time meter;

КР - terminal connector;

PB - processor unit;

PT - superheater pipe;

UOP - the node of the RAM of the processor unit;

UOPN - PB unit for determination of reduced mechanical stress;

RBM - PB unit for determining the total and residual life of the PT;

UOET - PB unit for determining the EET of a superheater pipe;

EET is the equivalent operating temperature.

Explanation of parameter indices

h - stock (coefficient);

isp - used (share);

n is the nominal value;

ost - residual (thickness) and residual (resource);

p - full (resource);

f - ferrite phase;

e - exploitation (beginning);

equiv - equivalent (according to operating conditions);

O - oxygen (concentration).

List of drawing items

10 - PB; 11.12 - KR; 13 - OOP; 14 - UOET; 15 - OOPN; 16 - ITV; 17 - RBM; 20 - VFN; 30 - VUZT; 40 - keyboard; 50 - display.

Utility Model Implementation

The device according to the utility model for determining the total and residual life of superheater pipes (PT) made of austenitic steel contains:

a processor unit (PB) 10 with terminal sockets (КР) 11, 12 for connecting, respectively, a remote ferritometric tip (VFN) 20 and a remote ultrasonic thickness gauge (VUZT) 30;

connected to the specified PB 10 keyboard 40 for entering the necessary additional values, as well as the data of the necessary measurements with the standard measuring means of the power plant (not shown) and a display 50 for visualizing the input and output data.

Moreover, PB 10 contains:

a random access memory unit (UOP) 13 for storing input information, a node (UET) 14 for determining the equivalent operating temperature (EET) of the outer surface of the PT according to measurements using the indicated WFN 20 of the mass-average concentration of the ferritic phase in the metal on the outer surface of the PT and using the standard an oxygen meter (not shown) the concentration of oxygen in flue gases, in accordance with the ratio:

where T _eq is the equivalent temperature, K; with _f - the mass-average concentration of the ferritic phase in the metal on the outer surface of the superheater pipes,%; with _O - the average value of the oxygen concentration in the gas medium washing the superheater, kg / m ³ ; R = 8.314 J / (mol · K) is the universal gas constant; A, B, C - experimentally determined constants depending on the grade of austenitic steel;

node (UOPN) 15 for determining the reduced mechanical stress in the metal of the PT according to the measurement using the specified VUZT 30 of the residual wall thickness of the pipe and the known initial value of the nominal inner diameter of these pipes, as well as the known value of the excess steam pressure at the inlet of the PT, in accordance with ratio:

where σ is the reduced stress in the metal of superheater pipes, MPa; p is the excess steam pressure at the entrance to the superheater pipes in the basic mode of operation according to the boiler passport, MPa; d _n - initial nominal internal diameter of superheater pipes according to the boiler passport, mm; s _ost - residual wall thickness of the superheater pipe, mm;

current time meter (ITV) 16 from the moment of the start of operation of controlled transformer substations;

node RBM 17 to determine:

the full resource of the specified PT in accordance with the ratio:

where τ _p - the full resource of superheater pipes, h;

E, F, G - experimentally determined constants, depending on the grade of austenitic steel; K _s - safety factor;

used share of the specified full resource in accordance with the ratio:

where τ _e is the current time from the beginning of the operation of controlled transformer substations, h share of residual life in accordance with the ratio:

and the residual life of the specified PT in accordance with the ratios:

where τ _ost - residual life of reliable operation of superheater pipes, h

The operation of the device is as follows.

To obtain initial information on the state of PT made of austenitic steel after each scheduled or emergency shutdown of the boiler using VFN 20, VUZT 30, and also the keyboard 40, data on the mass-average concentration of the ferrite phase in the metal on the outer surface of the PT, concentration are entered into the UOP 13 PB 10 oxygen in the gas medium washing the superheater (in flue gases), the initial and residual wall thickness of the metal PT, the excess vapor pressure at the inlet to them and other necessary quantities. The information received goes to nodes 14-16 of PB 10 to determine the intermediate values by the ratios (1), (2), then to RBM 17 to determine the desired values of the total resource, the fraction of the residual resource from the total and residual resource of the PT in hours. The obtained values of the intermediate and output values are displayed on the display 50 of the device.

Industrial applicability

The device according to the utility model meets the condition of "industrial applicability". The essence of the technical solution is disclosed in the formula, description and drawing clearly enough for understanding and industrial implementation by appropriate specialists based on the current state of the art in the field of heat power engineering.

Claims (1)

A device for determining the total and residual life of superheater pipes made of austenitic steel, containing: a processor unit with terminal sockets for connecting a remote ferrite tip and a remote ultrasonic thickness gauge; a keyboard connected to the indicated processor unit for inputting the necessary additional values, as well as data of necessary measurements with the standard measuring means of the power station and a display for visualizing input and output data; moreover, the specified processor unit includes: a processor unit for determining the equivalent operating temperature of the outer surface of the superheater pipes according to measurements using the specified remote ferritometric tip of the mass-average concentration of ferrite phase in the metal on the outer surface of the superheater and using a standard oxygen meter for the concentration of oxygen in flue gases, in accordance with the ratio: $$T_{\mathrm{uh}\mathrm{to}\mathrm{at}}=-\frac{B}{R\ln \left[{\left(\frac{c_f}{\mathrm{BUT}\cdot c_O}\right)}^2{\tau }^{-C}\right]},\left(\mathrm{one}\right)$$

where T _equiv - equivalent temperature, K; with _f - the mass-average concentration of the ferritic phase in the metal on the outer surface of the superheater pipes,%; with _about - the average value of the oxygen concentration in the gas medium washing the superheater, kg / m ³ ; R = 8.314 J / (mol · K) is the universal gas constant; A, B, C - experimentally determined constants depending on the grade of austenitic steel; a processor unit for determining the reduced mechanical stress in the metal of superheater pipes according to the measurement data using the specified external ultrasonic thickness gauge of the residual pipe wall thickness and the known initial value of the nominal internal diameter of these pipes, as well as the known value of the excess steam pressure at the entrance to them, in accordance with the ratio :

where σ is the reduced stress in the metal of superheater pipes, MPa; p is the excess steam pressure at the entrance to the superheater pipes in the basic mode of operation according to the boiler passport, MPa; d _n - initial nominal internal diameter of superheater pipes according to the boiler passport, mm; s _ost - residual wall thickness of the superheater pipe, mm; current time meter since the start of operation of controlled steam superheater pipes; processor node to determine: the full resource of these superheater pipes in accordance with the ratio:

where τ _p - the full resource of superheater pipes, h;

E, F, G - experimentally determined constants, depending on the grade of austenitic steel; K _s - safety factor; used share of the specified full resource in accordance with the ratio:

where τ _e is the current time since the start of operation of controlled superheater pipes, h; share of residual life in accordance with the ratio:

and the residual life of these superheater pipes in accordance with the ratios:

where τ _ost - residual life of reliable operation of superheater pipes, h

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