CN105300832B

CN105300832B - Fault diagnosis method for on-line detection device of carbon content in fly ash by weight loss method

Info

Publication number: CN105300832B
Application number: CN201510491866.1A
Authority: CN
Inventors: 王金铭; 解海龙
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-08-12
Filing date: 2015-08-12
Publication date: 2020-08-04
Anticipated expiration: 2035-08-12
Also published as: CN105300832A

Abstract

The invention relates to a fault diagnosis method for a device for online detecting the carbon content of fly ash by a weightlessness method, which is characterized in that the accurate judgment of faults and hidden dangers thereof is realized by means of a specially designed cantilever structure, the existing positioning sensor and weighing balance of a detection device and the integrated judgment logic of the invention embedded in a control system. The method can find the fault and the hidden danger thereof in time, start the corresponding disposal program, avoid the occurrence of accidents and the abnormity of detection results, improve the reliability and the service life of the detection device, reduce the maintenance amount and ensure the continuity of the detection. More reliable data support and regulation and control effect feedback are provided for combustion control, the regulation and control accuracy is effectively improved, and powerful guarantee is provided for ensuring economic operation and low nitrogen oxide emission of a large coal-fired boiler.

Description

Fault diagnosis method for on-line detection device of carbon content in fly ash by weight loss method

Technical Field

The invention relates to a fault diagnosis method for a device (hereinafter referred to as a detection device) for online detecting the carbon content of fly ash by a weightlessness method.

Background

The carbon content of fly ash is an important index for reflecting the operation economy of a large coal-fired boiler and is also an indispensable basis for optimizing combustion and controlling low nitrogen oxide emission. The existing detection device has the problems of high failure rate, large maintenance amount and unstable sampling amount, is a ubiquitous problem at present, directly influences the continuity and correctness of detection, and cannot meet the requirement of guiding boiler combustion control. Therefore, the method monitors the running states of all parts of the detection device in real time, accurately judges the faults and hidden dangers thereof, and starts corresponding disposal programs in time, and is the key for ensuring the reliable and continuous running of the detection device. However, the device has many faults that often occur, none of which is monitored by a specific sensor, such as: collision of the cantilever and each station, jamming of the executing mechanism, blockage of sampling and ash discharging channels, over-limit of sampling amount, damage or loss of the crucible and the like. Therefore, in practical applications, the light person causes the detection data to be inaccurate or interrupted, and the heavy person causes the device to be damaged.

Disclosure of Invention

The invention provides a method for monitoring specific faults and hidden dangers of a detection device, which realizes accurate judgment of the faults and the hidden dangers by means of a specially designed cantilever structure, the existing positioning sensor and weighing balance of the detection device and the integrated judgment logic of the invention embedded in a control system.

The technical problem to be solved by the method and the adopted technical scheme are as follows:

1. method for monitoring and judging collision fault between cantilever and each station

A special structure is constructed to insulate the cantilever made of metal from each station part. Each station component is fixed on the metal platform, each part of the station component can be used as one contact of the switch, the cantilever becomes the other contact, and the two contacts are connected to a switching value input port of a control system by using a lead. Once a collision occurs, a switching value signal is generated, so that the collision is judged; the position of the impact can then be determined from the signal output by the angle sensor for positioning the cantilever.

2. Method for monitoring and judging jamming fault of actuating mechanism

The actuating mechanism of the device comprises four vertical lifting mechanisms and a rotatable cantilever mechanism, wherein the former mechanism is provided with a positioning sensor, and the latter mechanism is provided with an angle sensor to determine the respective working positions. When a displacement control command is sent, the time for each mechanism to reach the new position can be calculated. Therefore, the time required by each displacement is calculated, and if the sensor which indicates the new position does not send in-place signals in the required time period after sending the instruction, the mechanism can be judged to have jamming faults.

3. Method for monitoring and judging faults of blockage of sampling and ash discharging channel, overrun of sampling amount, damage or loss of crucible and the like

Such failures have a common feature, namely that abnormal changes in weight occur at the time of failure. Therefore, the failure or the hidden danger is judged by means of the weighing balance on the detection device, and the specific judgment rule is as follows:

blockage of a sampling channel: the ash weight after sampling was approximately 0 (wherein: ash weight = total weight-crucible weight, the same applies below);

the sampling amount exceeds the upper limit: the weight of the sampled ash is greater than the set upper limit value;

the sampling amount exceeds the lower limit: the weight of the sampled ash is less than the set lower limit value;

blockage of an ash discharge channel: the ash weight is more than 0 after ash discharge;

crucible damage or loss: at any time of weighing, the total weight was 0.

In a similar way, some abnormal phenomena which do not influence the operation of the detection device temporarily, namely accident potential can be found.

And the judgment result is provided for a control system of the detection device, and a corresponding disposal program is started, so that the fault or hidden danger is processed in time.

The beneficial effects brought by the invention are as follows:

the reliability and the service life of the detection device are improved, the maintenance amount is reduced, and the detection continuity is ensured. More reliable data support and regulation and control effect feedback are provided for combustion control, the regulation and control accuracy is effectively improved, and powerful guarantee is provided for ensuring economic operation and low nitrogen oxide emission of a large coal-fired boiler.

Drawings

The attached drawing is a schematic diagram of stations and an execution mechanism of the fly ash carbon content online detection device, and the fly ash carbon content online detection device comprises four stations of vertical lifting mechanisms and a rotatable cantilever mechanism.

In the figure: 1. the system comprises a sampling station 2, a weighing station 3, a control system 4, an ash discharging station 5, a cantilever mechanism 6 and a firing station.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

In the embodiment, an analytical balance of a weighing station 2, a control system 3, actuating mechanisms of stations (1, 4, 5 and 6) and positioning sensors or angle sensors of the actuating mechanisms are weighed by an original detection device, wherein the control system adopts an industrial programmable controller (P L C), the positioning sensors adopt Hall proximity switches, and the angle sensors adopt high-resolution encoders.

The specific implementation process is as follows:

1. monitoring and judging collision fault between cantilever and each station

Processing a connecting piece made of insulating materials to connect the cantilever on the cantilever mechanism 5 with the base in an insulating way, and leading out a lead on the cantilever; and another lead is led out from the metal platform fixed with the parts of the stations (1, 2, 4 and 6). Two wires are connected to the switching value input port of the control system 3. Once collision occurs, two contacts which are equivalent to switches are closed, and the control system 3 receives a switching value signal so as to judge that the collision occurs; the location of the impact can then be determined from the angular signal output by the high resolution encoder that positions the cantilever.

2. Actuator jam fault monitoring and determination

The actuating mechanism of the device comprises four vertical lifting mechanisms (

stations

1, 2, 4 and 6) and a rotatable cantilever mechanism 5, wherein the former is determined by a Hall proximity switch, the latter is determined by a high-resolution encoder to determine respective working positions, and the time required by each displacement which is calculated in advance is stored in a control system 3. If the control system 3 does not send in-place signals to the sensor indicating the new position in the corresponding time period after sending a displacement instruction to a certain execution mechanism, the mechanism can be judged to have a jamming fault; and the executing mechanism receiving the displacement command is the position where the collision occurs.

3. Monitoring and judging faults such as blockage of sampling and ash discharging channels, overrun of sampling amount, damage or loss of crucible and the like

After the sampling process is executed, the crucible is transferred to a weighing station 2 from a sampling station 1 by a cantilever on a cantilever mechanism 5 for weighing, and if the ash weight obtained by a control system 3 is approximately 0, the blockage of a sampling channel can be judged; if the ash is larger than the set upper limit value, the sampling amount can be judged to exceed the upper limit value; if the ash weight is less than the set lower limit value, the sampling amount can be judged to exceed the lower limit value.

After the ash discharging process is executed, the crucible is transferred to the weighing station 2 from the ash discharging station 4 by the cantilever on the cantilever mechanism 5 for weighing, and if the ash obtained by the control system 3 is more than 0, namely residue exists in the crucible, the blockage of the ash discharging channel can be judged.

At any time of weighing, if the total weight obtained by the control system 3 is 0, it can be judged that the crucible is damaged or lost.

Through the embodiment, the diagnosis of specific faults of the zero-gravity method fly ash carbon content online detection device is realized, the diagnosis can be used as a trigger condition for starting a corresponding treatment program, the faults and hidden dangers thereof are timely treated, and the normal operation of the detection device is ensured.

Claims

1. A method for diagnosing the failure of the on-line detection device of the carbon content in fly ash by weightlessness features that a failure diagnosing mechanism is built, and the comprehensive judging logics of special cantilever structure, original positioning sensor, weighing balance and embedded control system are used to judge the failure of common failure and its hidden trouble, including collision, jamming, blocking of sampling and ash-discharging channel, over-limit of sampling quantity and damage or loss of crucible.