KR100794559B1 - Detection of poor fluidization in a fluidized bed ash cooler - Google Patents

Abstract

A method for detecting defluidization in a fluidized bed ash cooler is provided to prevent unstable fluidization caused due to clinker resulting from defluidization. A method for detecting defluidization in a fluidized bed ash cooler(10) is characterized in that sensors for measuring variation of pressure in a high frequency are attached individually to distribution pipes(32) arranged in the fluidized bed ash cooler. The detection of defluidization is carried out by altering the variation of pressure into an accumulated sum of standard error for predetermined time.

Description

Non-flow diagnostic method in air dispersion system of fluidized bed ash cooler {Detection of poor fluidization in a fluidized bed ash cooler}

1 is a schematic diagram showing the form of a fluidized bed ash cooler having an air dispersion system of the prior art.

Figure 2 is a graph showing changes in pressure and flow rate fluctuations during steady state and non-flow zones upon application of non-flow diagnostic techniques of the prior art.

Figure 3 is a schematic diagram showing the fluidized bed ash cooler type and the fluidized state by the bubble having a non-flow diagnostic system of the present invention.

Figure 4 is a graph measuring the pressure fluctuations at the time of steady state and non-flow using the high frequency pressure fluctuation sensor according to the present invention.

5a or 5b is a graph showing changes in pressure and flow rate fluctuations during steady state and non-flow zones in accordance with the present invention.

<Explanation of symbols for the main parts of the drawings>

10: fluidized bed ash cooler 12: air box

14 dispersion plate 16 air nozzle

18: flow medium 20: ash injection hole

22: ash discharge port 32: air dispersion plate

34: nozzle connection line 36: automatic pressure meter

38: flow control device 40: non-flow region

42: Bubble in normal fluidized bed 44: Bubble in non-fluidized area

The present invention relates to a non-flow diagnostic technique in an air dispersion system of a fluidized bed ash cooler, and more particularly, by defluidization in a fluidized bed heat exchanger that cools and discharges a high temperature ash discharged from a circulating fluidized bed or bubble fluidized bed. Non-flow diagnostic techniques in the air dispersion system of the fluidized bed ash cooler which instruct the early diagnosis of generated particle agglomeration and clinker formation and forcing the air supply or forced discharge of ash to solve the flow instability. It is about.

In the circulating fluidized bed and bubble fluidized bed boilers, it is necessary to discharge ash which accumulates in the combustion furnace continuously increasing during the combustion of coal or fossil fuel, and the dry treatment through heat recovery provides many advantages for the direct recycling of ash. . The fluidized bed ash cooler installed for this purpose is a device that absorbs and cools the heat of ash, and is composed of a bubble fluidized bed which has relatively high heat transfer and heat absorption rate and is capable of dry treatment of ash. The high temperature (about 850 ° C.) ash introduced into the fluidized bed ash cooler from the combustion furnace is flow mixed in the ash cooler to transfer heat to the water cooling pipe installed in the ash cooler, and is cooled and discharged.

The most important operating variable during the sequence of heat transfer and heat transfer into and out of the hot bed ash cooler is the particle size and fluidization air flow rate, which is closely related to the proper fluidization of the particles.

However, the particle size of the ash injected into the fluidized bed ash cooler is not a control parameter in the fluidized bed ash cooler because the particle size of the fuel used in the combustion furnace is mainly affected, and the air flow rate, i. Control is the main control parameter. If adequate fluidization air volume for the particle size is not supplied, that is, an excessive supply or insufficient supply of the required fluidization air volume causes significant problems for stable operation. When the amount of air is excessively supplied, not only energy loss due to air pressure loss, but also abrasion of the internal water cooling pipe due to violent movement of particles may be exacerbated.

On the other hand, when the air supply is insufficient, serious problems of clinker formation and shutdown due to agglomeration of hot particles in the non-fluidized zone may occur. For this reason, proper control and supply of fluidized air is a very important operational control parameter in fluidized bed ash coolers.

However, the supply of fluidized bed operating air in a typical fluidized bed ash cooler may be such that a controlled amount of controlled air is injected through the air box and fed to the fluidized bed ash cooler in bulk through the nozzles of the distributor plate, or several air supply mains ( branched by a header). In this case, even when an initial amount of controlled air is injected, the overall homogeneous fluidization in the fluidized bed ash cooler can be somewhat unreasonable, resulting in local non-flow zones and shutdowns due to clinker production. As a result, the operation of actual fluidized bed ash coolers (eg, Donghae thermal circulating fluidized bed boilers) requires regular removal of clinkers, continuous particle management and facility maintenance.

For this reason, the optimal air dispersion system (Korea Patent No. 10-0559690) of the fluidized bed ash cooler developed by the present researchers is a system configured to supply and control uniform fluidized air by overcoming the above disadvantages.

However, the method of detecting clinker formation in the fluidized bed low-cooler by detecting the average value of the fluidized bed pressure fluctuation and the change in flow rate described in the above technical development is frequently operated when the fluidized air volume is changed frequently or when the fluidized air volume is insufficient. The detection effect was low.

In addition, it is considered that there is a lot of difficulty in initial diagnosis and removal of the clinker because the flow rate can be detected only after generation of the clinker for a long time to amplify the detection effect.

Referring to the conventional concept of the diagnostic technique, as illustrated in FIG. 1, the optimal air dispersion system of the fluidized bed ash cooler is a fluidized bed ash cooler 10, the ash inlet 20, the exhaust 22 system, and a solid. Dispersion plate 14 for supporting the flow medium 18 and the nozzle 16 system for the injection of air, the dispersion system configured for the injection of air is configured at right angles to the solid discharge flow based on the nozzle (14) Air dispersion pipe 32, a connecting line 34 connecting the air dispersion pipe and the nozzle, an air flow regulator 38 for adjusting the flow rate to the air dispersion pipe and an automatic pressure meter 36 capable of measuring pressure fluctuations It consists of). Dispersion pipe (32) for nozzle injection of fluidized air is configured to be perpendicular to the solid discharge flow so as to smoothly discharge the solid as well as the discharge flow in the fluidized bed ash cooler and to adjust the amount of flow air at each position. .

Conventional clinker generation diagnostics from the system are detected through long-term average values of pressure and flow fluctuations at steady state and changes in pressure averages and flow rate averages at flow failure or clinker generation as shown in FIG. This is because when the non-flow zone is formed, the solid trapped at the top acts as an increase factor of the pressure in the dispersion pipe, and due to this pressure increase factor, the low flow rate is supplied (F1) and the pressure in the non-flow zone in the part where the flow is activated. The flow rate decrease due to the increase is additionally supplied to detect the phenomenon in which the flow rate increases (F2, F3) to determine the generation of the non-flow zone.

However, as described in Korean Patent No. 10-0559690, when the total air volume is constant, it is mainly detectable when the total air volume changes frequently, or the local flow rate changes due to insufficient pressure increase in the non-flowing region. Incomplete cases also make it difficult to detect clinker or non-flowing areas.

The present invention has been made to solve the above problems, an object of the present invention is generated by defluidization in a fluidized bed heat exchanger for cooling and discharging the high temperature ash discharged from the circulating fluidized bed or bubble fluidized bed. It provides a non-flow diagnostic technique in the air dispersion system of a fluidized bed ash cooler that diagnoses particle agglomeration and clinker formation at an early stage and instructs the air supply or forced discharge of ash to solve the flow instability. have.

The present invention has the following configuration to achieve the above object.

The non-flow diagnostic technique in the air dispersion system of the fluidized bed ash cooler of the present invention is characterized in that a sensor for measuring the pressure fluctuation value in the form of high frequency is separately attached to the dispersion pipe provided in the fluidized bed ash cooler to which the optimum air dispersion system is applied. It is done.

In addition, by changing the signal system to a cumulative sum of the standard error (Standaed-error) for a certain time to perform a non-flow diagnostics, the standard error value measured from the pressure fluctuation of the dispersion pipe After analyzing the non-flowing and the non-flowing region through the analysis to automatically adjust the air volume of the dispersion pipe.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

First, since the present invention is described based on the configuration described in FIG. 1, the fluidized bed ash cooler 10, the dispersion plate 14, the air nozzle 16, the fluidized medium 18, the ash inlet 20, and the ash Further description of the outlet 22, the air dispersion pipe 32, the nozzle connection line 34 and the automatic pressure meter 36 will be omitted.

As shown in FIG. 3, the non-flow diagnosis technique of the fluidized bed ash cooler is a sensor (not shown) for measuring a high frequency pressure fluctuation value in an air dispersion pipe 32 provided in the fluidized bed ash cooler to which an optimum air dispersion system is applied. Are attached separately to show the formation and dissipation of bubbles 42 in the normal fluidized bed and the formation and dissipation of bubbles 44 in the non-flow zone 40. The generation and dissipation of the bubbles 42 in the steady state causes the pressure fluctuations of the lower air dispersion pipe 32 to change periodically with a certain pattern.

In particular, referring to P1 and P2 shown in FIG. 4, in the normal flow state at the time of disappearance of bubbles, the extinction is represented as the breaking (explosion) of the bubbles at the surface of the fluidized bed and the width of the pressure fluctuation is relatively large. And, referring to P3 and P4 of FIG. 4, when the non-flow zone 40 is generated, a weaker pressure than that in the normal fluidized bed because the rise of bubbles is slowed or the bubbles are broken or decomposed and dissipated in the non-flow zone. It gives a change signal. Therefore, if the pressure fluctuation signal is measured and monitored in real time using a sensor (not shown) attached to the air dispersion pipe 32 and converted into a more amplified signal system, as shown in FIG. 5A or 5B, the non-flow region ( When 40) occurs, the signal value shows a sharp decrease, so it is easy to know whether or not non-flow occurs. In addition, converting the real-time signal of the pressure fluctuation into the amplified signal system (SSt) can be expressed as the cumulative sum of the standard error (SSt) for a predetermined time (t), as shown in the following equation.

,

으로 표현되어지며, n과 i, j는 측정 데이터의 처리 개수를, x_i는 실시간 압력 변동값을 의미한다. 이때 측정 데이터의 처리 개수가 클수록 비유동 지역 발생시 신호체계(SSt)는 더 큰 감소폭을 나타내게 된다. 따라서, 도 5a 또는 도5b에 나타낸 바와 같이 압력 변동 처리 신호로부터 비유동 발생의 유무를 알 수 있을 뿐만 아니라 압력변동의 측정 위치에 따라 비유동 발생 지역을 추정할 수 있어, 이의 해소를 통한 안정적 운전에 큰 기여를 할 수 있게 된다. 즉, 본 발명에 의한 유동층 회재 냉각기에서의 비유동 진단 기법은 최적 분산 시스템을 이용한 유동층 회재 냉각기에서 클링커 생성 혹은 비유동 지역의 발생으로 인한 불안정 운전을 초기에 감지하여 최적의 유동 상태를 상시 구현할 수 있도록 하였다. 또한 전체 유동화 공기량 변화가 빈번한 경우와 미비한 국부적 유량 변화로 인해 비유동 감지가 어려운 경우에도 이를 가능케 하여 안정적 운전에 대처할 기술 기반을 제공할 수 있도록 하였다. 더불어 실시간 클링커 생성 및 비유동 지역의 감시를 통해 실시간 공기유량 조절 기능과 연계가 가능할 수 있게 하여 비유동 지역의 해소를 통한 운전의 안정화와 자동화를 달성할 수 있을 것으로 기대된다.here,

,

N, i, j are the number of processing of the measurement data, x _i is the real-time pressure fluctuation value. At this time, the larger the number of processing of the measurement data, the greater the decrease in the signal system SSt when the non-flow region occurs. Therefore, as shown in FIG. 5A or 5B, not only the presence or absence of non-flow occurrence can be seen from the pressure fluctuation processing signal, but also the non-flow generation region can be estimated according to the measurement position of the pressure fluctuation, which is great for stable operation by eliminating it. You can contribute. In other words, the non-flow diagnosis technique in the fluidized bed ash cooler according to the present invention enables to realize the optimal flow state at all times by initially detecting the unstable operation caused by the clinker generation or the occurrence of the non-flowed area in the fluidized bed ash cooler using the optimal dispersion system. . In addition, it is possible to provide a technology foundation to cope with stable operation by making it possible to detect non-flow due to frequent changes in the total fluidized air volume and inadequate local flow changes. In addition, real-time clinker generation and monitoring of non-floating areas can be linked with real-time air flow control functions, and it is expected to achieve stabilization and automation of operation by eliminating non-flowing areas.

The present invention is not limited to the embodiments described above, and various modifications and changes can be made by those skilled in the art, which are included in the spirit and scope of the present invention as defined in the appended claims.

According to the present invention, in the fluidized bed heat exchanger, which cools and discharges the high-temperature ash discharged from the circulating fluidized bed or the bubbled fluidized bed, an initial diagnosis of particle agglomeration and clinker generation caused by defluidization is performed, thereby resulting in flow instability. It has the effect of instructing in advance so that the air supply or the forced discharge of ashes can be done.

In addition, it is possible to detect the flow failure of the ash injected into the fluidized bed ash cooler in the early stage, providing a foundation for always implementing the optimum flow state.

In addition, it is possible to detect the non-flow zone even when the total fluidization air volume changes frequently in the fluidized bed ash cooler and insignificant local flow and pressure changes, so that real-time clinker generation and monitoring of the non-flow zone can be linked with the real-time air flow control function. It is expected that stabilization and automation of operation can be achieved by eliminating non-floating areas.

Claims (3)

A non-flow diagnostic method for an air dispersing device for a fluidized bed ash cooler, wherein a sensor for measuring a high frequency pressure fluctuation value is individually attached to a dispersion pipe provided in a fluidized bed ash cooler to which an optimum air dispersion system is applied. The method of claim 1, Non-flow diagnostic method in the air dispersing device of a fluidized bed ash cooler, characterized in that for changing the signaling system to the cumulative sum of the standard error (Standaed-error) for a predetermined time. The method of claim 1, Fluidized bed ash cooler characterized in that to automatically adjust the air volume of the dispersion pipe after performing the detection of the non-flow and the non-flowing region by analyzing the standard error (Standaed-error) value measured from the pressure fluctuation of the dispersion pipe Non-flow Diagnostics Method for Air Dispersion in .

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