解析燃气烘炉火焰检测不稳定改造

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【摘要】本文是以烘炉燃烧时火焰检测设备的故障全过程为实例,探讨分析影响烘炉火焰检测稳定的各种因素,详述与之相对应的检修对策及效果,说明通过改进修检工艺,可以有效地提高烘炉灭火保护装置的可靠性。 【 abstract 】 this article is based on oven burning flame detection equipment failure process as an example, analyzes factors which influenced the stability of the oven flame detection, detail and the corresponding repair measures and effect, and that by improving the inspection process, can effectively improve the reliability of oven fire protection device. 　　【关键词】电离电极;火焰监测器;程序控制器;稳定性 【 key words 】 the ionization electrode; Flame monitor; Program controller; The stability 　　　　 　　1 前言 1 introduction 　　 　　笔者对广州某公司在运转的三台烘炉进行了半年时间的观察及检测,发现了因设计、安装质量、检修调整、燃烧工况(调整)等诸多问题,炉膛外火焰检测信号长期不稳定,多次出现保护误动现象,严重影响了机组的安全稳定运行。一方面火检装置本身存在不稳定因素,另一方面燃烧控制设备可控性差;燃烧调整不当又反过来影响火检的稳定,并多次影响工作效率,本文就怎样对烘炉火焰检测改造进行探讨。 The author a company working in guangzhou three oven for half a year's observation and testing, found due to the quality of design, installation, maintenance adjustment (adjustment), combustion conditions and so on many issues, outside the furnace flame detection signal is not stable for a long time, multiple occurrences of protection misoperation phenomenon, seriously affecting the safe and stable operation of the unit. Fire detection device itself exists unstable factors on one hand, on the other hand, poor combustion control equipment control; Improper combustion adjustment, in turn, influence the stability of the flame detector, and influence work efficiency many times, this article on how to oven flame detection transformation were discussed. 　　 　　2 影响火检稳定的因素分析 Two factors affecting the stability of the flame detector is analyzed 　　 　　从烘炉设备分析火检不稳定原因应从火检装置本身和燃烧变化两个方面进行分析,找出制约火检光(电)信号传输、处理不合理环节和燃烧工况变差的因素,并采取有效的检修对策改进设备、燃烧控制以及改善调整,完全可以消除锅炉火检不稳定现象,这在1号、2号炉改造后15个火检的良好运行工况得到了证明。 From oven equipment this paper analyzes the reasons of unstable flame detector should from the device itself and the combustion flame detector changes two aspects carries on the analysis, find the fire detector (electricity) light signal transmission, processing, unreasonable links and combustion condition, and take effective maintenance measures to improve equipment, combustion control, and improve the adjustment, can completely eliminate the phenomenon of boiler flame detector is not stable, after the reform in boiler no. 1, 2, 15 got prove that fire inspection of good operation condition. 　　2.1 火焰监测器安装位置不合理。 2.1 the flame monitor installation position is not reasonable. 　　火焰监测器的安装位置、倾角在导光管中的相对位置两个问题。由于燃气燃烧器扩散角、初燃区范围大小的差异,所以导光管与燃烧器倾角安装,并以一定的倾角对准初燃区中部靠前处,如果导光管没对准初燃区或者插入困难而没有伸到位影响视角,都会严重影响检光效果。火检信号偏弱,不能正确反映燃烧的实际工况,燃烧负荷较低时,易误发无火信号。(图1) The installation location, Angle of the flame monitor the relative position of two questions in the light pipe. Due to gas burner diffusion Angle, in the early combustion zone size difference, so the light pipe installation with the burner Angle, and aim at a certain Angle in the early combustion zone in central front place, if the light pipe out early combustion zone or insert difficult without stretch in place influence Angle, will seriously affect the light effect. Fire detection signal is weak, can not correctly reflect the actual working condition of the combustion, combustion at low load, easy to mistakenly send no fire signal. (figure 1) 　　2.2 火焰监测器能变差或积灰。 2.2 the flame monitor can worsen or dust. 　　由于导光管冷却效果不好而造成导光管前端温度过高,使导光管过早老化,且探头维护不善易积灰,二者都会严重影响通光性能(透光率),使紫外光亮度信号在传输过程中大大减弱,从而使火检信号不稳定。 Due to bad cooling effect of the light guide light guide front temperature is too high, make the light guide premature aging, and probe poorly maintained dust easily, both are seriously affecting the optical properties (transmittance) and the ultraviolet luminance signal during transmission greatly reduced, so that the flame detector signal is not stable. 　　2.3 火焰监测器参数调整不合理。 2.3 the flame monitor parameter adjustment is not reasonable. 　　处理好灵敏度和分辨能力两个方面的问题,既要有足够的灵敏度保证火检信号的稳定,又要将本身的火焰同与其相邻、相对的焰区分开来。火检参数调整不当主要表现在如下方面: Handle both sensitivity and resolution of problems, should not only have enough sensitivity to the stability of the flame monitoring signals of guarantee, and flame with adjacent to itself, apart from the relative flame. Improper parameter adjustment of the flame detector is mainly embodied in the following aspects: 　　2.3.1 在燃气燃烧的工况下调整火检,由于火焰是离燃烧器19.6mm左右向前燃烧,火焰长度是296mm,经监测后火检参数与检测实际工况不符。 2.3.1 in gas combustion adjustment under the condition of fire, because fire is around 19.6 mm burner combustion, the flame length is 296 mm, after monitoring the parameters of the flame detector and the detection of actual working condition. 　　2.3.2 在调整单台火检时没有减少给气量进行试验、调整。 2.3.2 when adjusting a single fire inspection did not decrease for gas testing and adjustment. 　　2.3.3 中心频率设定不准,由于初燃区火焰闪烁的频率不仅与煤气质有关,而且与空气浓度有关,因此中心频率的设定宜在60%～70%额定负荷下进行试验、设定,满负荷和最低负荷下调整、设定中心频率都是不合理的。 2.3.3 center frequency setting is not allowed, because the early combustion zone flame flicker frequency not only related with the gas quality, and is associated with air concentration, so the center frequency of the set should be under 60% ~ 70% rated load test, the setting, full load and the minimum load adjustment, setting the center frequency is not reasonable. 　　2.3.4 调整后的火检参数没有进行低负荷、变煤气质(种)的试验和长时间的考验,一旦遇到比试验更差的工况,则可能出现大面积火检不稳而产生保护误动。 2.3.4 after adjusting the parameters of the flame detector to low load, the gas mass (kind of) test and the length of the test of time, once encounter less than the test conditions, may appear unstable area fire detection and protection misoperation. 　　2.3.5 没有处理好灵敏度和分辨能力之间的矛盾关系,存在一定的漏检、误检的隐患。 2.3.5 did not deal with the contradiction between the sensitivity and resolving power relations, there is leak and mistakenly identified hazards. 　　2.4 煤气量的变化及一次风过量。 2.4 the quantity of gas and the wind too much at a time. 　　煤气量变差或煤气热值降低,则会使煤气着火距离后移,使初燃区中心偏离原来火检导光管对准的区域,亮度、频率会因此而发生变化,影响火检信号的稳定,同样风机一次风量过大,未燃区会因一次风速增高、煤气细度增大而加长,也会使煤气着火距离后移,典型的情况是锅炉低负荷(低于65%额定负荷)下磨一次风量过大,对火检有明显影响,这种运行工况应尽量避免。 Gas quantity difference or gas calorific value is reduced, can make gas ignition distance moved, at the beginning of the combustion zone center deviating from the original light pipe alignment area flame detector, intensity, frequency will change because of this, the stability of the flame monitoring signals of influence, as a fan air volume is too big, not combustion zone due to a higher wind speed and the fineness degree of the gas increases, longer, also can make gas ignition distance backward-shift, typically boiler under low load (less than 65% the rated load) grinding a air volume is too big, had significant effect on the fire inspection, the operation condition should be avoided. 　　2.5 燃烧控制设备可靠性差及摆动异常。 2.5 abnormal combustion control equipment reliability is poor and swing. 　　主要是燃烧器摆角和二次风挡板,燃烧器摆角控制异常,部分摆到最高、最低,特别是同一层摆角,因喷口烧损变形卡住原因,使摆角出现有的上摆到顶、有的下摆到底的情况,烘炉正常切向燃烧遭到破坏,紫外光导向管跟随摆动,燃烧器初燃区火焰仍然偏离检测区,火焰回流效果差,同时紫外光在导光管中的位置会因摆动相对后移,使火检信号偏弱而不稳,特别是低负荷更明显,不但火检不稳,还会损坏燃气阀组。 Mainly swinging Angle of burner and secondary air baffle, the swinging Angle of burner control abnormal, place to the highest and lowest part, especially in the same layer angular, stuck due to the burning of the nozzle deformation reason, make the pendulum Angle appear some on to, in some cases the hem in the end, oven normal tangential combustion destroyed, ultraviolet light pipe run follow swinging, the burner flame combustion zone is still at the beginning of deviating from the detection area, poor flame backflow effect, at the same time uv in the light guide position will due to the relatively backward, make the signal weak and unstable flame detector, especially more obvious under low load, unstable flame detector, not only can damage the gas valve group. 　　二次风挡板开不到位也是严重影响燃烧的因素之一,使燃烧器燃烧配风不够,燃烧工况恶化而使火检不稳。 Secondary air baffle opening does not reach the designated position is one of the serious factors affecting combustion, the combustion burner air distribution is not enough, unstable combustion condition deterioration and make the fire inspection. 3 改造方案 3 retrofit scheme 　　 　　3.1 要改用电离电极重新定位。 3.1 to convert the ionization electrode repositioning. 　　电离电极安装在喷口前方的火焰口内,火焰要与电极要相互垂直安装。威索公司根据燃烧器的尺寸、喷口扩散角、额定工况一次风速和燃气压力,空气压力,燃气检漏确定了火焰的长度为倾角为60°左右,并向前燃烧300mm长火焰,而电离电极要与火焰稳焰器垂直并相距20mm。还要做好绝缘和防高温处理和降温处理(图2) Ionization electrode is installed in the flame inside the mouth in front of the nozzle, the flame with electrodes perpendicular to install. Weishaupt company according to the size of the burner, nozzle Angle, the rated working condition of a gas pressure, wind speed and air pressure, gas leak detection to determine the length of the flame inclination to 60 °, and 300 mm long flame combustion, and ionization electrode and the flame stabilizing vertical flame device and 20 mm apart. For insulation and heat treatment and cooling (figure 2) 　　 　　 　　3.2 改造后的工作过程。 3.2 after transforming the work process. 　　烘炉的燃烧是由程序控制器LFL1.333给予一定吹扫时间,并点火在3秒钟内对火焰检测电离电极是否有导通电流30~50uA返回程序控制器分析如有30-50uA通过则燃烧器继续燃烧,否则熄火和报警,火焰要燃烧充分并有良好蓝色和白红色的火焰,这样才能保护好电离电极不会结垢而不能正常状态工作。 Oven combustion is a program controller LFL1.333 offer certain purging time and ignition of flame ionization detection within 3 seconds if there is a drive electrode current 30 ~ 50 ua return analysis if there is a 30-50 ua program controller through the burner to burn, or shut down and alarm, fire will burn sufficiently and blue and white and red flame is good, in this way can we protect the ionization electrode will not scale and can't normal work. 　　3.3 两台炉目前火检设备改造前后对比。 3.3 two furnace fire inspection comparison before and after the equipment reform at present. 　　电离电极检测是只要有火焰燃烧就有电流通过,并能安全保护整套设备正常状态工作。 Ionization electrode detection is as long as the flame is the current through, and the set safety protection equipment normal work. 　　火焰监测器检测不能有效检测火焰如导光管有灰和不反光,还有其它光线的干扰和误动作还有火焰燃烧不稳定而做成不能正常工作对火检设备进行长达一年的对比后,两台炉共有15个火检,设备本身缺陷已完全消除,火检装置的参数改造已全面完善,能比较真实地反映烘炉单个燃烧器的燃烧工况,终于实现两台炉火检设备缺陷“0”目标。 Flame monitor tests are not effective flame detection such as light pipe is grey and not reflective, and other light interference and false action and flame instability and make it can't work normally fire inspection equipment for up to one year after contrast, a total of 15 fire inspection two furnace, the equipment itself defect has been completely eliminated, the parameters of the flame monitoring device has a comprehensive, can more truly reflect the oven single burner combustion condition, finally realize the two fire detection equipment defects "zero" goal. 　　3.4 烘炉改造后火检效益。 3.4 oven after transforming the fire inspection efficiency. 　　2007年5月～2008年5月,1号、2号机火检误动仅0次,已大大降低误动作,还能提高生产效率,提高工作质量。 In May 2007 to May 2008, no. 1, no. 2 machine maloperation of the flame detector is only 0 times, has greatly reduce misoperation, it can improve the production efficiency, improve the quality of work. 　　通过火检综合测检,调试后一年没有发生过烘炉灭火保护误动,工作一年内没有发生保护误动而造成停产,灭火保护装置的可靠性明显提高。烘炉运行良好的工作状态,充分体现了其在技术改良后的稳定性,确保了生产效率及工作质量的提高。 By fire inspection comprehensive measurement inspection, debugging after one year there have been no oven fire protection maloperation, working within a year of protection misoperation caused production does not occur, the reliability of the fire protection system has improved significantly. Oven running in good working condition, fully embodies the its stability after technical improvement, to ensure the production efficiency and improve the quality of our work.