外文翻譯---PLC在蒸汽鍋爐汽包液位PID控制系統(tǒng)的應(yīng)用分析

1、.附錄2：外文翻譯PLC in steam boiler steam drum fluid position PID control system applied analysis 1 introductionThe industry steam boiler steam drum water monitor duty is the control causes it for the water current capacity with the transpiration rate maintenance dynamical equilibrium, maintains the steam

2、drum water level in the craft permission scope, is guarantees the boiler safety in production movement the essential condition, also is one of boiler regular production movement major targets or quotas. If the water level excessively is high, affects the soft drink separation the effect, the use was

3、 mad the equipment breaks down; But the water level excessively low can destroy the soft drink circulation, is serious when causes the explosion of a boiler, therefore the boiler steam drum water level must strictly control. In order to guarantee the boiler to produce stable, reliable and the econom

4、ical movement, we designed use the performance to be advanced the boiler PID automatic control system which forever great automatic equipment and so on FBs-PLC, frequency conversion velometer, computer application will compose. This control system through examination water vapor pressure, temperatur

5、e, movement physical quantity and so on steam drum fluid position, in movement process entire automatic control, has guaranteed the industry boiler security stable highly effective movement.2 industries boilers related craft introductionThe steam boiler is the factories and mines important power equ

6、ipment, its duty is the supplies qualified stable steam, satisfies the load the need. Therefore, boiler production process each main parameter all must strictly control. But holds the very great proportion using the afterheat gas as the heat change medium afterheat boiler in the nation, its energy c

7、onservation falls consumes the effect especially to be obvious. Some chemical plant sulfuric acid afterheat boiler is the furnace gas which comes out using the ebullition stove (mainly is SO2) the hyperpyrexia, takes it as the heat change object, through afterheat boiler vice- mid-production pressur

8、e steam for each production branch factory use, also has guaranteed the production need, also had achieved the energy conservation falls the goal which consumes. The boiler is a more complex controlled member, provides the qualified steam for the guarantee to meet the load need, if the necessary des

9、ign control system must satisfy each main craft parameter the need. Afterheat boiler technical process like chart 1 shows:3 controls difficulties analysisThe boiler computer control is a new technology which the recent years developed. It is the microcomputer soft, the hardware, the automatic contro

10、l, the boiler energy conservation and so on several technical in close integration with product, as the boiler control device, its primary mission is guaranteed the boiler the security, is stable, the economical movement, reduces operator's labor intensity. Uses the micro computer control, can c

11、arry on the process to the boiler the automatic detection, the automatic control and so on many functions. It is adjusted the quantity is the steam drum water level, but adjusts the quantity is for the water current capacity, through to gives the water current capacity the adjustment, enables the st

12、eam drum interior the material to achieve the dynamical equilibrium, changes in the permission scope, although the boiler steam drum water level assumes the positive characteristic to the vapor current capacity and for the fluent quantity change response, but when load (vapor current capacity) sharp

13、 growth, performance actually similar counter response characteristic, namely so-called false water level. Creates this reason is because time load increase, causes the dome pressure to drop, causes the steam drum 內(nèi)水 boiling temperature to drop, the water ebullition suddenly intensifies, forms the m

14、assive steam bubbles, but makes the water level to raise. The steam drum water monitor system, in the essence is maintains the boiler turnover water volume balance the system. It is by the water level took the water volume balance or not control target, through adjusts the water volume how many to a

15、chieve the turnover balance, maintains the steam drum water level in the soft drink separation contact surface biggest steam drum nearby the position line, enhances the boiler the vaporization efficiency, the guarantee production safety. Because the boiler water level system is equipped with the bal

16、ance of the ability to control the object, in the movement has the false water level phenomenon, in the practical application may use the water level single impulse, the water level steam quantity double impulse and the water level, the steam quantity according to the situation, gives the water volu

17、me three impulses the control systems. The so-called three impulses governing system is gives water current capacity W, steam drum water level H, the steam current capacity D three variables adjusts after the operation gives the water valve the governing system. Concrete adjustment process block dia

18、gram like chart 2 shows.First and obtains respective signal through vapor stream quantitative change delivering for fluent quantitative change delivering while by the corresponding scale-up factor, may adjust the steam current capacity through the scale-up factor or give the water current capacity t

19、o the governing system influence dynamics. Changes delivering through the difference pressure to obtain the water level signal to take host adjustment signal H. If the water level supposes the definite value is G, then should have under the equilibrium condition D×Dk-W×Wk+H-G=0 relational

20、type existence. Dk is steam discharge coefficient Wk gives the water discharge coefficient. If again establishes time, guaranteed D×Dk=W×Wk that may obtain H=G under the stable state. This time the regulator output on with conforms to the correspondence, stops to the water valve in some po

21、sition. If has or many signals changes, the state of equilibrium is destroyed, the PI adjustment module output will certainly to change. When the water level elevated, then the adjustment module output signal reduces, causes to close slightly for the water regulating valve. Otherwise, when the water

22、 level reduces, the adjustment module output value increases, causes to open in a big way to the water valve. The practice proved three impulses can maintain the water level for the water single pole regulator system stably, also gives the water regulating valve movement to be steady. The boiler als

23、o has a quite important control loop for the aqueous system in is for the hydraulic pressure return route, because the steam drum internal pressure is higher, must make up the water to the boiler to have to provide a higher pressure, enhances the hydraulic pressure for the hydraulic pressure return

24、route function, enables the water normally to pour into the steam drum. But in the steam current capacity had not achieved when full load, to gives the water current capacity the request not to be high. Generally uses the feed pump in the old style boiler system continuously by the labor frequency w

25、ay revolution, reduces the hydraulic pressure with the return valve to prevent the cartridge igniter, now generally uses through the frequency changer constant pressure water supply way control hydraulic pressure. Boiler to water volume through steam drum fluid position adjustment. The steam drum fl

26、uid position survey selects floats the tube liquidometer. For the effective use transformation waste heat, reduces the consumption, decreases the labor intensity, is advantageous is stable to the overall craft, requests the steam drum fluid position automatic control, when regular production the und

27、ulation should be smaller than ±5%. The PID adjustment steam outlet valve may the very good control dome pressure. After drives normally undulates the scope not to be big, may not consider. The transformed load undulation, the pre-heater boiler for the water temperature change, the boiler load

28、undulation, dumps pollutants the quantitative change these factors to have to consider to the steam drum fluid position influence. Take the steam drum fluid position as the main tuning parameter, take gives the water current capacity as the vice- accent parameter, take the steam current capacity as

29、a forward feed, but the adjustment effect is very bad. Causes the steam drum fluid position major rises and falls. Considered this waste heat boiler controlled variable coupling small, flow simple, produces the steam quantity to be also stabler, we are inspired from in operator's operation, thin

30、ks the reduction thus to stabilize to the water volume undulation to the water temperature becomes this waste heat boiler fluid position control the main point. Therefore we select "to the steam decide the water + fluid position forward feed" the ratio control plan, plan diagram like chart

31、 3 shows.中文原文PLC在蒸汽鍋爐汽包液位PID控制系統(tǒng)的應(yīng)用分析1 引言 工業(yè)蒸汽鍋爐汽包水位控制的任務(wù)是控制給水流量使其與蒸發(fā)量保持動(dòng)態(tài)平衡，維持汽包水位在工藝允許的范圍內(nèi)，是保證鍋爐安全生產(chǎn)運(yùn)行的必要條件，也是鍋爐正常生產(chǎn)運(yùn)行的主要指標(biāo)之一。若水位過(guò)高,影響汽水分離的效果,使用氣設(shè)備發(fā)生故障;而水位過(guò)低則會(huì)破壞汽水循環(huán),嚴(yán)重時(shí)導(dǎo)致鍋爐爆炸，所以鍋爐汽包水位必須嚴(yán)加控制。為了確保鍋爐生產(chǎn)的穩(wěn)定、可靠和經(jīng)濟(jì)運(yùn)行，我們?cè)O(shè)計(jì)采用了性能先進(jìn)的永宏FBs-PLC、變頻調(diào)速器、計(jì)算機(jī)應(yīng)用等自動(dòng)化設(shè)備組成的鍋爐PID自動(dòng)控制系統(tǒng)。該控制系統(tǒng)通過(guò)檢測(cè)水汽壓力、溫度，汽包液位等運(yùn)行物理量，在運(yùn)行過(guò)程

32、中全自動(dòng)調(diào)節(jié)，保證了工業(yè)鍋爐的安全穩(wěn)定高效運(yùn)行。2 工業(yè)鍋爐相關(guān)工藝介紹 蒸汽鍋爐是廠(chǎng)礦重要的動(dòng)力設(shè)備，其任務(wù)是供給合格穩(wěn)定的蒸汽，以滿(mǎn)足負(fù)荷的需要。為此，鍋爐生產(chǎn)過(guò)程的各個(gè)主要參數(shù)都必須嚴(yán)格控制。而利用余熱氣體作為熱交換介質(zhì)的余熱鍋爐在全國(guó)占有很大的比例，其節(jié)能降耗效果尤為明顯。某化工廠(chǎng)硫酸余熱鍋爐就是利用沸騰爐出來(lái)的爐氣(主要是SO2)溫度過(guò)高，將其作為熱交換對(duì)象，通過(guò)余熱鍋爐副產(chǎn)中壓蒸汽供各生產(chǎn)分廠(chǎng)使用，既保證了生產(chǎn)需要，也達(dá)到了節(jié)能降耗的目的。鍋爐是一個(gè)較為復(fù)雜的調(diào)節(jié)對(duì)象，為保證提供合格的蒸汽以適應(yīng)負(fù)荷的需要，與其配套設(shè)計(jì)的控制系統(tǒng)必須滿(mǎn)足各主要工藝參數(shù)的需要。余熱鍋爐工藝流程如圖1所

33、示。 3 控制難點(diǎn)分析 鍋爐計(jì)算機(jī)控制是近年來(lái)開(kāi)發(fā)的一項(xiàng)新技術(shù)。它是微型計(jì)算機(jī)軟、硬件、自動(dòng)控制、鍋爐節(jié)能等幾項(xiàng)技術(shù)緊密結(jié)合的產(chǎn)物，作為鍋爐控制裝置，其主要任務(wù)是保證鍋爐的安全、穩(wěn)定、經(jīng)濟(jì)運(yùn)行，減輕操作人員的勞動(dòng)強(qiáng)度。采用微計(jì)算機(jī)控制，能對(duì)鍋爐進(jìn)行過(guò)程的自動(dòng)檢測(cè)、自動(dòng)控制等多項(xiàng)功能。它的被調(diào)量是汽包水位，而調(diào)節(jié)量則是給水流量，通過(guò)對(duì)給水流量的調(diào)節(jié)，使汽包內(nèi)部的物料達(dá)到動(dòng)態(tài)平衡，變化在允許范圍之內(nèi)，雖然鍋爐汽包水位對(duì)蒸氣流量和給水流量變化的響應(yīng)呈積極特性，但是在負(fù)荷(蒸氣流量)急劇增加時(shí)，表現(xiàn)卻類(lèi)似逆響應(yīng)特性，即所謂的虛假水位。造成這一原因是由于負(fù)荷增加時(shí)，導(dǎo)致汽包壓力下降，使汽包內(nèi)水的沸點(diǎn)溫度下降，水的沸騰突然加劇，形成大量汽泡，而使水位抬高。汽包水位控制系統(tǒng)，實(shí)質(zhì)上是維持鍋爐進(jìn)出水量平衡