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1、基于模糊理论的焦炉加热多模式控制冯如鹤 庞元俊 （平顶山工业职业技术学院 河南 平顶山 467001）摘要：焦炉炼焦是一个复杂的间歇式操作的热工过程, 火道温度是焦炉生产中一个非常重要的工艺参数, 直接影响产品能耗的高低与质量的稳定,本文介绍了火道温度的检测与数学模型的建立；采用模糊理论用于焦炉加热的多模式自动控制。关键词：焦炉 火道温度 蓄顶温度 模糊控制The Multimode Control of The Coke Oven/s Heating Based On The Fuzzy TheoryFENG Ruhe, PANG Yuanjun（Pingdingshan Industria
2、l College of Technology, Pingdingshan Henan 467001） Abstract:The process of coking is a complicated intermission operational hot working process.The fire road tempreture is a very important technological parameter in the coke oven production,effecting the relative superiority of the product/s energy
3、 consumption and the stability of the quality directly.This text introduced the fire road tempreture/s examination and the mathematics model/s establish,adopting fuzzy theory for the multimode autocontrol of the coke oven/s heating.Key Words:Coke oven; Fire road tempreture; With the top tempreture；
4、Fuzzy control1 前言焦炉炼焦是一个复杂的间歇式操作的热工过程,它由若干个炭化室和燃烧室交替配置组成。煤气和空气在燃烧室里混合、扩散、燃烧,产生的热量通过辐射对流的形式传递给炭化室,煤料在炭化室中隔绝空气加热(高温干馏)形成焦炭,燃烧室里煤气燃烧产生的废气经蓄热室、烟道排放出去。目前国内的大部分焦炉生产过程还是以人工操作为主,辅以一些简单的自动化手段,自动化水平较低。火道温度的检测主要是用光学高温计,检测的精度低,实时性差,因而必然导致产品的能耗高,品质不稳定,环境污染十分严重。解决这一问题的关键是必须有一种行之有效的控制方法和检测手段。2 火道温度的检测与数学模型的建立火道温度是
5、焦炉生产中一个非常重要的工艺参数,它直接影响产品能耗的高低与质量的稳定,但在技术上难以实现火道温度的在线连续检测。根据焦炉生产工艺可知,火道温度与蓄热室顶部温度是相关的,可通过蓄热室顶部温度来间接反映火道温度的高低。为此针对平顶山天宏焦化公司3#炉,在机焦侧各选工况条件较好的10个蓄热室(20#29#),并分别在其顶部装上S型热电偶,直接测量蓄热室顶部下降气流温度,该温度在每个交换周期内是连续变化的, 但在交换后10分钟左右,变化较平稳,故取此刻的温度作为最终的测量值。在双联火道型焦炉,每个蓄热室与两个燃烧室相联,10个蓄热室事实上联系着20个燃烧室,10个蓄热室顶部温度的平均值(以下简称蓄顶
6、温度)基本上可代表全炉的平均火道温度(以下简称火道温度)的变化。图1是平顶山天宏焦化公司3#炉连续200个小时内实测的火道温度与蓄顶温度之间对应关系的数据,考虑到光学高温计的精度和不同测火工的人为误差,图1中的数据可以认为,它们之间有良好的相关性。图2为由上述数据经线性回归后得出的蓄顶温度和火道温度的对应关系曲线:机侧:Tc1=790.0+0.47t1 (1)焦侧:Tc2=770.0+0.50t2 (2)式中Tc1机侧火道温度t1机侧蓄顶温度Tc2焦侧火道温度t2焦侧蓄顶温度它们的相关系数R=0.85,已满足工业控制的要求。在生产工况比较稳定的情况下,用蓄顶温度间接地代表火道温度能及时灵敏地反
7、映燃烧室的温度变化,并且测量的精度较高。在实际运行中,为了避免热电偶的老化以及蓄热室高温事故所导致的误检测,需对蓄顶温度设置13551255115510559551 5 9 13 17 21 25 29 33 37 测量次序系列1系列2图1 火道温度与蓄顶温度对应关系火道（蓄顶）温度上下限报警值,并采取相应的处理措施。1040 1050 1060 1070 1080 1090 蓄顶温度1260火道温度123012351240124512501255图2 火道温度与蓄顶温度线性回归曲线Y 预测Y3 控制方案的设计焦炉加热控制的目的是在规定的结焦时间内,用较少的煤气生产出合格的焦炭。因此焦炉加热控
8、制要解决两个问题:一是在规定的目标火道温度下,采用何种控制算法才能获得最佳的控制效果;二是目标火道温度的优化。在本系统的控制方案设计中,重点研究了上述两个问题。3.1 目标火道温度的优化是机、焦侧火道温度平均值的目标值,它是在规定的结焦时间内保证焦饼成熟的一个主要工艺指标,目标值定得过高,单位产品的能耗迅速上升,并易造成“扒焦”现象, 费时费力，定得过低，焦碳不能成熟。根据统计分析发现,火道温度每升高10度,炼焦耗热量就增加95kJ/kg,因此,目标火道温度的确定是焦炉节能降耗的一个重要环节,影响目标火道温度的因素主要有结焦时间和焦饼中心温度,以及装炉煤的堆密度、含水量、炭化室宽度、炉墙厚度等
9、。式(3)是由炭化室传热模型1并根据成品焦炭的挥发份的分析进行修正而推导出的目标火道温度的函数:T（f）=181.6+455.5+4.8m +1696w-1276.8d +0.5t-29.151 (3)式中堆密度 m配煤水分 结焦时间 w炭化室宽度 d炉墙厚度 t目标焦饼中心温度3.2 火道温度的反馈控制焦炉是一个典型的大惯性非线性时变的复杂系统,干扰因素很多,它的过渡过程时间长达810小时,并且过程特性参数受装煤量、煤的性质、含水量等参数影响较大。因此采用传统的控制方法难以获得好的控制效果。图3是本系统所采用的控制系统框图,分别以火道温度和高炉煤气压力为主、副回路的被控参数,引入副回路的目的
10、是为了克服高炉煤气总管压力的频繁波动,以保证煤气流量的相对稳定,它的控制规律为PI调节,采样周期为1s。主回路采用多模式模糊控制,每隔20min,根据火道温度的高低调整煤气压力控制系统的设定值。E6E6火道温度煤气压力Bang Bang 控制模糊控制PI煤气管侧焦炉目标火道温度图3控制系统框图2.3 多模式模糊控制算法模糊控制规则是模拟人对生产过程的控制操作经验而总结出来.的,现场的操作经验是:若火道温度高于目标值5且有上升趋势,减少高炉煤气压力100Pa;若火道温度低于目标值5且有下降趋势,增加高炉煤气压力100Pa;其他情况,基本不作调整。设焦炉的火道温度的目标值为Tf,实测值为Tc,则:
11、火道温度偏差e(k)=Tf-Tc火道温度的变化趋势e(k)=e(k)-e(k-1)式中e(k)当前时刻偏差e(k-1)前一采样时刻偏差取偏差e(k)、变化趋势e(k)以及控制输出的语言变量分别为E、EC和U,它们的模糊子集为:E=PB PM PS O NS NM NB;EC=PB PM PS O NS NM NB;U=PB PM PS O NS NM NB;它们的论域为:E=-6-5-4-3-2-10+1+2+3+4+5+6;EC=-6-5-4-3-2-10+1+2+3+4+5+6;U=-6-5-4-3-2-10+1+2+3+4+5+6;焦炉实际的火道温度基本上在(1240-20,1240+2
12、0)范围内变化,而生产工艺要求温度的波动在(-7,7)内,若温度偏差的论域选得过大,控制精度差,若把温度偏差E的量化等级分得更精细一些,将导致控制规则复杂化。因此采用压缩论域的方法,以改善控制系统的静态特性。取E的基本论域为:(-5.5,+5.5)。温度变化趋势EC的基本论域为(-2,+2)/h,控制输出U的基本论域为(700,1100)Pa。为了便于控制规则的在线调整,采用解析式表述的控制规则 U=E+(1-)EC(01)公式为取整运算,式中为调整因子,通过调整的大小可以调整模糊控制规则,亦即改变E、EC在控制输出中的权重。当偏差较大时,控制系统的主要任务是尽快消除偏差,此时偏差E的权重应大
13、一些,而当偏差较小时,控制系统的主要任务是使系统尽快稳定下来,这时偏差的变化EC的权重应大一些,取:=1/3(1 -2)| E |+2根据现场操作经验和反复调试,取1=0.80,2=0.35比较合理。采取这种自调整模糊控制规则,有利于尽快的消除偏差和提高系统的稳定性。当生产工况有变动时,温度的变化往往会超过(-5.5,+5.5)范围,若仍采用上述方法,由于焦炉的大惯性,必然会导致超调量大,调节时间过长。针对上述情况,在控制过程中增加了一个预测部分。即首先对温度的偏差进行判断,当e(k)的范围不超过(-5.5,+5.5)时,采用模糊控制;若温度超过上述范围,则控制输出调到上限值或下限值即Bang
14、Bang控制。这样既保证了控制的精度,又保证了被控对象的快速性。4 结论本文设计的控制方案在平顶山天宏焦化公司3#炉投入了实际运行,从运行结果来看,多模式模糊控制方案能够较好地克服焦炉加热系统中的各种干扰因素,鲁棒性强,控制效果良好。作者简介： 冯如鹤（1965），河南平顶山人，毕业于河南理工大学机械系，现任教于平顶山工业技术学院。副教授，发表论文多篇。 通讯地址： 河南 平顶山水库路3号 平顶山工业职业技术学院教务处 冯如鹤邮 编： 467001电 话： 手机：13569551299办公：0375 2066474Editors note: Judson Jones is a meteorol
15、ogist, journalist and photographer. He has freelanced with CNN for four years, covering severe weather from tornadoes to typhoons. Follow him on Twitter: jnjonesjr (CNN) - I will always wonder what it was like to huddle around a shortwave radio and through the crackling static from space hear the fa
16、int beeps of the worlds first satellite - Sputnik. I also missed watching Neil Armstrong step foot on the moon and the first space shuttle take off for the stars. Those events were way before my time.As a kid, I was fascinated with what goes on in the sky, and when NASA pulled the plug on the shuttl
17、e program I was heartbroken. Yet the privatized space race has renewed my childhood dreams to reach for the stars.As a meteorologist, Ive still seen many important weather and space events, but right now, if you were sitting next to me, youd hear my foot tapping rapidly under my desk. Im anxious for
18、 the next one: a space capsule hanging from a crane in the New Mexico desert.Its like the set for a George Lucas movie floating to the edge of space.You and I will have the chance to watch a man take a leap into an unimaginable free fall from the edge of space - live.The (lack of) air up there Watch
19、 man jump from 96,000 feet Tuesday, I sat at work glued to the live stream of the Red Bull Stratos Mission. I watched the balloons positioned at different altitudes in the sky to test the winds, knowing that if they would just line up in a vertical straight line we would be go for launch.I feel this
20、 mission was created for me because I am also a journalist and a photographer, but above all I live for taking a leap of faith - the feeling of pushing the envelope into uncharted territory.The guy who is going to do this, Felix Baumgartner, must have that same feeling, at a level I will never reach
21、. However, it did not stop me from feeling his pain when a gust of swirling wind kicked up and twisted the partially filled balloon that would take him to the upper end of our atmosphere. As soon as the 40-acre balloon, with skin no thicker than a dry cleaning bag, scraped the ground I knew it was o
22、ver.How claustrophobia almost grounded supersonic skydiverWith each twist, you could see the wrinkles of disappointment on the face of the current record holder and capcom (capsule communications), Col. Joe Kittinger. He hung his head low in mission control as he told Baumgartner the disappointing n
23、ews: Mission aborted.The supersonic descent could happen as early as Sunday.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attac
24、hed, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into
25、the stratosphere. As he crosses the boundary layer (called the tropopause), he can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet (22.7 miles/36.53 kilometers). Here, Fearless Felix will unclip. He will roll back the door.Then, I would assume, he will s
26、lowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be l
27、ike he is diving into the shallow end.Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will
28、not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1
29、,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wont. Baumgartner still will free fall at a speed that wou
30、ld cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).It might not be the moon, but Kittinger free fell from 102,800 feet in 1960 - at the dawn of an infamous space race that captured the hearts of many. Baumgartner will attempt to break that record, a feat that boggles the mind. This is one of those monumental moments I will always remember, because there is no way Id miss this.
