外文翻譯--- 燃煤鍋爐的燃燒進(jìn)程控制

1、<p>　　Controlling the Furnace Process in Coal-Fired Boilers</p><p>　　The unstable trends that exist in the market of fuel supplied to thermal power plants and the situations in which the parameters of t

2、heir operation need to be changed (or preserved), as well as the tendency toward the economical and environmental requirements placed on them becoming more stringent, are factors that make the problem of controlling the

3、combustion and heat transfer processes in furnace devices very urgent. The solution to this problem has two aspects. The first involves development</p><p>　　The experience Central Boiler-Turbine Institute Re

4、search and Production Association (TsKTI) and ZiO specialists gained from operation of boilers and experimental investigations they carried out on models allowed them to propose several new designs of multifuel and maneu

5、verable—in other words, controllable—furnace devices that had been put in operation at power stations for several years. Along with this, an approximate zero-one-dimensional, zonewise calculation model of the furnace pro

6、cess in bo</p><p>　　Naturally, furnace process adjustment methods like changing the air excess factor, stack gas recirculation fraction, and distribution of fuel and air among the tiers of burners, as well a

7、s other operations written in the boiler operational chart, are used during boiler operation.However, the effect they have on the process is limited in nature. On the other hand, control of the furnace process in a boile

8、r implies the possibility of making substantial changes in the conditions under which the com</p><p>　　(i) the flows of oxidizer and gases being set to move in the flame in a desired aerodynamic manner;</

9、p><p>　　(ii) the method used to supply fuel into the furnace and the place at which it is admitted thereto;</p><p>　　(iii) the fineness to which the fuel is milled.</p><p>　　The latter

10、 case implies that a flame-bed method is used along with the flame method for combusting fuel.The bed combustion method can be implemented in three design versions: mechanical grates with a dense bed, fluidized-bed furna

11、ces, and spouted-bed furnaces.</p><p>　　As will be shown below, the first factor can be made to work by setting up bulky vortices transferring large volumes of air and combustion products across and along t

12、he furnace device. If fuel is fired in a flame, the optimal method of feeding it to the furnace is to admit it to the zones near the centers of circulating vortices, a situation especially typical of highly intense furna

13、ce devices. The combustion process in these zones features a low air excess factor (α< 1) and a long local time f</p><p>　　Also important for the control of a furnace process when solid fuel is fired is t

14、he fineness to which it is milled; if we wish to minimize incomplete combustion, the degree to which fuel is milled should be harmonized with the location at which the fuel is admitted into the furnace and the method for

15、 supplying it there, for the occurrence of unburned carbon may be due not only to incomplete combustion of large-size fuel fractions, but also due to fine ones failing to ignite (especially when the </p><p>

16、　　Owing to the possibility of pictorially demonstrating the motion of flows, furnace aerodynamics is attracting a great deal of attention of researchers and designers who develop and improve furnace devices. At the same

17、time, furnace aerodynamics lies at the heart of mixing (mass transfer), a process the quantitative parameters of which can be estimated only indirectly or by special measurements. The quality with which components are mi

18、xed in the furnace chamber proper depends on the number, layou</p><p>　　It was suggested that the gas-jet throw distance be used as a parameter determining the degree to which fuel is mixed with air in the g

19、as burner channel. Such an approach to estimating how efficient the mixing is may to a certain degree be used in analyzing the furnace as a mixing apparatus. Obviously, the greater the jet length (and its momentum), the

20、longer the time during which the velocity gradient it creates in the furnace will persist there, a parameter that determines how completely the f</p><p>　　It is was proposed that the extent to which once thr

21、ough jets are mixed as they penetrate with velocity w2 and density ρ2 into a transverse (drift) flow moving with velocity w1 and having density ρ1 be correlated with the relative jet throw distance in the following way&l

22、t;/p><p>　　Where ks is a proportionality factor that depends on the “pitch” between the jet axes (ks= 1.5–1.8).</p><p>　　The results of an experimental investigation inwhich the mixing of gas with

23、air in a burner and then in a furnace was studied using the incompleteness of mixing as a parameter are reported in 5.</p><p>　　A round once through jet is intensively mixed with the surrounding medium in a

24、furnace within its initial section, where the flow velocity at the jet axis is still equal to the velocity w2 at the nozzle orifice of radius r0.The velocity of the jet blown into the furnace drops very rapidly beyond th

25、e confines of the initial section, and the axis it has in the case of wall-mounted burners bends toward the outlet from the furnace.</p><p>　　One may consider that there are three theoretical models for anal

26、yzing the mixing of jets with flowrate G2 that enter into a stream with flowrate G1. The first model is for the case when jets flow into a “free” space (G1= 0),the second model is for the case when jets flow into a trans

27、verse (drift) current with flowrate G1G2，and the third model is for the case when jets flow into a drift stream with flowrate G1<G2. The second model represents mixing in the channel of a gas burner, and the third m&l

28、t;/p><p>　　At a = 0.07, the length of the round jet’s initial section is equal to 10 r0 and the radius the jet has at the transition section (at the end of the initial section) is equal to 3.3 r0. The mass flow

29、rate in the jet is doubled in this case. The corresponding minimum furnace cross-sectional area Ff for a round once through burner with the outlet cross-sectional area Fb will then be equal to and the ratio Ff/Fb≈20. Thi

30、s value is close to the actual values found in furnaces equipped with once throug</p><p>　　The method traditionally used to control the furnace process in large boilers consists of equipping them with a larg

31、e number of burners arranged in several tiers. Obviously, if the distance between the tiers is relatively small, operations on disconnecting or connecting them affect the entire process only slightly. A furnace design em

32、ploying large flat-flame burners equipped with means for controlling the flame core position using the aerodynamic principle is a step forward. Additional possibili</p><p>　　Unfortunately, we have to state t

33、hat, even at present, those in charge of selecting the type, quantity, and layout of burners in a furnace sometimes adopt technical solutions that are far from being optimal. This problem should therefore be considered i

34、n more detail. </p><p>　　If we increase the number of burners nb in a furnace while retaining their total cross-sectional area (ΣFb=idem) and the total flowrate of air through them, their equivalent diameter

35、s deq will become smaller, as willthe jet momentums Gbwb, resulting in a corresponding decrease in the jet throw distance hb and the mass they eject. The space with high velocity gradients also becomes smaller, resulting

36、 in poorer mixing in the furnace as a whole. This factor becomes especially important when the em</p><p>　　In [1], a quantitative relationship was established between the parameters characterizing the quali

37、ty with which once through jets mix with one another as they flow into a limited space with the geometrical parameter of concentration = with nb = idem and Gb = idem. By decreasing this parameter we improve the mass tran

38、sfer in the furnace; however, this entails an increase in the flow velocity and the expenditure of energy (pressure drop) in the burners with the same Fb. At the same time, we know </p><p>　　For illustration

39、 purposes, we will estimate the effect the number of burners has on the mixing in a furnace at = = idem. schematically shows the plan views of two furnace chambers differing in the number of once through round nozzles (t

40、wo and four) placed in a tier (on one side of the furnace). The furnaces have the same total outlet cross-sectional areas of the nozzles (ΣFb) and the same jet velocities related to these areas (wb). The well-known swirl

41、 furnace of the TsKTI has a design close to </p><p>　　The number of burners may be tentatively related to the furnace depth af (at the same = idem) using the expression (5)</p><p>　　It should be

42、 noted that the axes of two large opposite air nozzles ( = 1)—an arrangement implemented in an inverted furnace—had to be inclined downward by more than 50° [8].</p><p>　　One well-known example of a fur

43、nace device in which once through jets are used to create a large vortex covering a considerable part of its volume is a furnace with tangentially arranged burners. Such furnaces have received especially wide use in comb

44、ination with pulverizing fans. However, burners with channels having a small equivalent diameter are frequently used for firing low-calorific brown coals with high content of moisture. As a result, the jets of air-dust m

45、ixture and secondary air that</p><p>　　temperature level in the flame decreases, the combustion does not become less stable because the fuel mixes with air in a stepwise manner in a horizontal plane.</p&g

46、t;<p>　　Vortex furnace designs with large vortices the rotation axes of which are arranged transversely with respect to the main direction of gas flow have wide possibilities in terms of controlling the furnace pr

47、ocess. In [1], four furnace schemes with a controllable flame are described, which employ the principle of large jets colliding with one another; three of these schemes have been implemented. A boiler with a steam capaci

48、ty of 230 t/h has been retrofitted in accordance with one of these schemes </p><p>　　Below, two other techniques for controlling the furnace process are considered. Boilers with flame–stoker furnaces have ga

49、ined acceptance in industrial power engineering, devices that can be regarded to certain degree as controllable ones owing to the presence of two zones in them . Very different kinds of fuel can be jointly combusted in t

50、hese furnaces rather easily. An example of calculating such a furnace device is given in [2]. As for boilers of larger capacity, work on developing controllab</p><p>　　Centrifugal dust concentrators have rec

51、eived acceptance for firing high-reactive coals in schemes employing pulverizing fans to optimize the distribution of fuel as to its flowrate and fractions. The design of one such device is schematically shown in [9]. Fi

52、gure shows a distribution of fuel flowrates among four tiers of burners that is close to the optimum one. This distribution can be controlled if we furnish dust concentrators with a device with variable blades, a solutio

53、n that has an adequat</p><p>　　燃煤鍋爐的燃燒進(jìn)程控制 </p><p>　　存在于火電廠的市場(chǎng)的燃料供應(yīng)，某些操作參數(shù)需要改變（或保留）的情況下 ，以及經(jīng)濟(jì)和環(huán)境方面傾向的要求使他們變得更加嚴(yán)格的不穩(wěn)定趨勢(shì)是導(dǎo)致使控制燃燒與傳熱過(guò)程爐設(shè)備非常緊迫的主要因素。解決這個(gè)問(wèn)題的辦法有兩個(gè)方面。第一階段包括發(fā)展燃燒技術(shù)和當(dāng)新裝置設(shè)計(jì)時(shí)高爐的設(shè)計(jì)。第二階段包括現(xiàn)有

54、的現(xiàn)代化設(shè)備。在兩種情況下，技術(shù)精髓的采用必須通過(guò)類似試驗(yàn)與計(jì)算研究的使用來(lái)證實(shí)。有著豐富經(jīng)驗(yàn)的機(jī)組研究和生產(chǎn)協(xié)會(huì)（ TsKTI ）和齊奧專家取得鍋爐操作和實(shí)驗(yàn)進(jìn)行了調(diào)查，他們的模式使他們能夠提出一些新設(shè)計(jì)的混和機(jī)動(dòng)性，換言之，可控爐裝置已在發(fā)電站投入使用多年，與此同時(shí)，一種近似零一維，鍋爐爐膛燃燒進(jìn)程總線計(jì)算模型在TsKTI 已經(jīng)研制成功，這一模型允許TsKTI 專家獲取計(jì)算這一進(jìn)程中的主要參數(shù)，計(jì)算研究爐膛采用不同技術(shù)時(shí)的發(fā)射與燃燒

55、方式。當(dāng)然，火爐燃燒進(jìn)程的調(diào)整方法有諸如改變空氣過(guò)剩系數(shù)，煙氣再循環(huán)率，燃料和空氣在鍋爐空間內(nèi)的分配，以及其它在鍋爐運(yùn)行期間書(shū)面的控制圖表。然而，它們對(duì)進(jìn)程的影響自然是有限的。另一方面，控制鍋爐的燃燒進(jìn)程很可能意味著在某種條件下發(fā)成實(shí)質(zhì)性改變，在這種條件下發(fā)生燃燒和傳熱，目的是大</p><p>　　(i)流動(dòng)的氧化劑和氣體以一種期望的空氣動(dòng)力學(xué)方式在火焰中流動(dòng)</p><p>　　(ii

56、)將燃料供應(yīng)到火爐的方法并證實(shí)燃料已經(jīng)供應(yīng)到地方了</p><p>　　(iii)經(jīng)過(guò)研磨的優(yōu)良燃料</p><p>　　后者意味著火爐床的方法被用作帶有火焰的燃料燃燒過(guò)程。流化床燃燒的方法可以實(shí)施三個(gè)設(shè)計(jì)版本：帶有密集床的機(jī)械爐，流化床鍋爐，以及噴動(dòng)床爐。</p><p>　　正如一下所要展示的，第一個(gè)因素可以通過(guò)在鍋爐裝置周圍建立一些龐大的漩渦轉(zhuǎn)移大量的空氣和燃

57、燒產(chǎn)品來(lái)實(shí)現(xiàn)。如果燃料進(jìn)給是在火焰中進(jìn)行，最佳的進(jìn)給方式是將其進(jìn)給到漩渦中心區(qū)域附近，這種方式特別適用在高度密集爐設(shè)備中。在這一區(qū)域的燃燒過(guò)程具有較低的空氣過(guò)剩因數(shù)，在這一很長(zhǎng)過(guò)程時(shí)間內(nèi)這些成分都要存在于此，這一因素有助于使燃燒過(guò)程更穩(wěn)定和減少排放的氮氧化物 。</p><p>　　同樣重要的是，對(duì)于鍋爐燃燒控制過(guò)程，當(dāng)固體燃料燃燒時(shí)，也要優(yōu)化將燃料碾磨精化。如果我們要盡量減少不完全燃燒，燃料的研磨程度應(yīng)該與位置

58、相協(xié)調(diào)，在這一位置上，燃料被送進(jìn)爐膛，同時(shí)供應(yīng)燃料應(yīng)講究方法，因?yàn)樘嫉牟煌耆紵坏且驗(yàn)榇笮腿剂辖M分不完全燃燒，而且還因?yàn)槟承┙?jīng)過(guò)研磨的細(xì)質(zhì)不燃燒的緣故。（特別是某些揮發(fā)性的成分Vdaf<20%）。</p><p>　　由于存在繪畫(huà)般的顯示流體運(yùn)動(dòng)的可能性，鍋爐空氣動(dòng)力學(xué)吸引了大量研究人員和設(shè)計(jì)師的關(guān)注，他們一直致力于發(fā)展和改進(jìn)鍋爐設(shè)備。與此同時(shí)，鍋爐空氣動(dòng)力學(xué)的關(guān)鍵在于混合中心（集中的傳遞），這一過(guò)程的

59、可估計(jì)的定量參數(shù)，只能間接或特殊的測(cè)量。成分在爐膛內(nèi)混合的質(zhì)量嚴(yán)格上取決于數(shù)量，布局，還有從個(gè)別爐膛和噴嘴噴射出來(lái)的流體動(dòng)力，以及它們與流動(dòng)的廢氣或與墻壁的相互作用。</p><p>　　有人建議，氣體噴射距離可以作為參數(shù)確定氣體燃燒器通道中燃料與空氣的混合程度。這種如何估計(jì)有效混合的做法可以在一定的程度上用于混合裝置的爐的分析。顯然，越大的噴射距離（和其勢(shì)頭），造成的在爐膛內(nèi)持續(xù)存在的速度梯度的時(shí)間越長(zhǎng)，一個(gè)參

60、數(shù)，確定如何流動(dòng)中完全混合。注意，在噴嘴或燃燒器出口的噴射高度越高，它涵蓋的距離越短，因此，組成部分不完全是在爐體內(nèi)混合。一旦通過(guò)燃燒器便在漩渦這方面具有優(yōu)勢(shì)。</p><p>　　還有人提議，因?yàn)樗鼈円运俣葁2和密度ρ2滲透變成橫向（漂移）流移動(dòng)速度w1和密度ρ1，所以在噴嘴混合的程度與氣體噴射距離密切相關(guān)，以下列方式：公式（1）</p><p>　　Ks是相稱的因素，取決于射流軸線之間

61、的距離（Ks= 1.5至1.8）天然氣與空氣在爐中混合，然后在爐中使用不完整的混合技術(shù)的實(shí)驗(yàn)研究結(jié)果作為一個(gè)參數(shù)在[5]報(bào)告。</p><p>　　第一輪曾經(jīng)是密集射流與周圍介質(zhì)以其最初的形式混合的熔爐，在這里噴氣軸的流速仍然是等于在噴嘴孔半徑r0的速度W2。噴嘴吹入到爐的速度下降非常迅速，超越了最初一節(jié)的限制，壁掛式燃燒器的軸彎曲對(duì)準(zhǔn)爐的出口。</p><p>　　有人可能會(huì)認(rèn)為，有三個(gè)

62、理論模型用于分析流量G2和流量G1混流噴射的原理。第一種模式是噴射流入“自由”空間的情況（ G1= 0 ）；第二個(gè)模型是噴射流入橫向（漂移）的情況下，當(dāng)前的流量G1G2 ；第三個(gè)模型是當(dāng)噴射流入漂移流的情況下，此時(shí)流量G1<G2。第二種模型描述的是混合氣體燃燒器，第三種模式描述的是在爐膛內(nèi)的混合。我們認(rèn)為，與第二種模式相比在不久的將來(lái)我們即將擁有的混合模式更接近于第一種模式，因?yàn)? <G1/G2 < 1 ，我們將假定噴

63、射的漂移距離h等同于自由噴射的初始長(zhǎng)度S0.正在漂流的噴射的彈射能力等同于自由噴射的長(zhǎng)度，初始噴射的長(zhǎng)度能夠用眾所周知的公式確G.N.Abramovich ：S0 = 0.67r0 / a，在這里，a代表噴射結(jié)構(gòu)因數(shù)，r0代表噴嘴半徑。</p><p>　　在a= 0.07時(shí) ，噴嘴的初始噴射圓長(zhǎng)等同于10倍的r0，噴射過(guò)渡段（在初始噴射結(jié)束時(shí)）的半徑等同于3.3倍r0.集中噴射的流量是這種情形的兩倍。相應(yīng)的最小

64、爐周圍的代表性區(qū)域Ff一旦通過(guò)燃燒器出口區(qū)域Fb，這兩個(gè)區(qū)域?qū)⑾嗟韧?，他們的比例是Ff/Fb≈20。一旦通過(guò)燃燒器，這一值將接近于基于鍋爐設(shè)備的實(shí)際值。帶有旋流的鍋爐燃燒器，a = 0.14和Ff/Fb≈10。在兩種情況下，燃燒器之間的距離與在過(guò)渡階段的噴射直徑dtr相等，這與建立于實(shí)踐與建議的價(jià)值差別很小。</p><p>　　傳統(tǒng)的方法來(lái)控制大型鍋爐的爐內(nèi)過(guò)程包括給他們配備了大量的燃燒器，并將這些燃燒器安排在

65、幾個(gè)層次。顯然，如果層之間的距離比較小，斷開(kāi)或連接的行為對(duì)整個(gè)過(guò)程的影響可以忽略。鍋爐設(shè)計(jì)采用大平面火焰燃燒器裝備，意味著利用空氣動(dòng)力學(xué)原理控制火焰的燃燒中心是鍋爐發(fā)展歷程中先前邁出的一大步。對(duì)于控制蒸汽產(chǎn)量為600噸/小時(shí)TPE-214 and TPE-215 型鍋爐進(jìn)程，更多可能性是通過(guò)在兩個(gè)距離較大的層面上采用平面火焰燃燒器。這使人們有可能不僅提高或降低的火焰，而且還能集中或分散釋放的熱量。一個(gè)非常明顯的效果，是在烏克蘭和俄羅斯的

66、聯(lián)產(chǎn)鍋爐冶金產(chǎn)業(yè)中安裝萬(wàn)能（用于煤炭和平爐，焦化，自然氣體）平面燃燒器。</p><p>　　不幸的是，我們必須指出，即使在目前，那些負(fù)責(zé)選擇爐具類型，數(shù)量和布局所采用的技術(shù)解決方案，還遠(yuǎn)遠(yuǎn)沒(méi)有得到優(yōu)化。因此這個(gè)問(wèn)題應(yīng)考慮更多的細(xì)節(jié)。</p><p>　　如果我們?cè)黾訝t具數(shù)量，同時(shí)保留其總截面積（ ΣFb =idem）和通過(guò)他們的空氣總量，他們的等效直徑deq將變得越來(lái)越小，而噴射動(dòng)量Gb

67、wb 也會(huì)減小，導(dǎo)致噴射距離的相應(yīng)減少和集中退出。帶有高流速梯度的空間也變小，導(dǎo)致作為整體的爐子混合性變差。在燃料分配不均勻的情況下，當(dāng)采用分級(jí)燃燒(atαb<1)時(shí)，噴射氮氧化物和碳氧化物的比例很正確的時(shí)候，這一因素變得非常重要。定量關(guān)系被建立在以質(zhì)量和幾何參數(shù)的濃度為特征的參數(shù)上，質(zhì)量取決于混合噴射進(jìn)入有限空間的流量，幾何參數(shù)的濃度為ΣFb/Ff， nb=idem,Gb=idem。通過(guò)降低這個(gè)參數(shù)我們提高爐的傳質(zhì);然而，這需要

68、我們?cè)谙嗤腇b下，增加流體速度和能源的支出。與此同時(shí)，我們從經(jīng)驗(yàn)和計(jì)算中得知，良好的混合爐，如果我們采用大型的遠(yuǎn)程噴射爐，可不增加頂端的損失。這讓很多不是很嚴(yán)格的要求可以置于一致的水平上，在這一水平上，燃料必須被分配在爐內(nèi)。此外，燃料可能在這種情況下被傳送至該爐的某一位置，這一位置是需要從過(guò)程控制方面去考慮。</p><p>　　為便于說(shuō)明，我們將估計(jì)當(dāng)ΣFb/Ff=idem是混合爐數(shù)量的影響。圖標(biāo)1顯示了兩爐

69、膛放置在一層（爐子一側(cè)）的噴嘴數(shù)量的不同（2或者4）。該爐具有相同的噴嘴區(qū)域總出口橫斷面（ ΣFb ）和相同的噴射速度聯(lián)系著這些區(qū)域（wb）。眾所周知的TsKTI漩渦爐有一個(gè)接近于考慮下的爐具的設(shè)計(jì)方案。根據(jù)有關(guān)數(shù)據(jù)，以低于額定的量混合并通過(guò)燃燒器進(jìn)入爐體內(nèi)為特點(diǎn)的空氣指數(shù)βair，可用公式進(jìn)行估計(jì)：βair=1-5，這一公式范圍已經(jīng)被核實(shí)0.03-0.06，為爐膛配備了兩個(gè)前沿使其一次性通過(guò)燃燒器。顯然，如果我們?cè)黾尤紵鞯臄?shù)量到因數(shù)

70、2，其當(dāng)量直徑，初始噴射區(qū)域的長(zhǎng)度S0和他們所“服務(wù)”的區(qū)域因數(shù)將減小，例如，當(dāng)a=0.05，分?jǐn)?shù)βair將由0.75減少至0.65 ，因此，在通過(guò)對(duì)經(jīng)過(guò)燃燒器進(jìn)入爐內(nèi)混合的質(zhì)量的影響進(jìn)行評(píng)估后，上述公式可以寫(xiě)成：βair=1-3.5，在這里nb是在一面墻上燃燒器（或空氣噴嘴）的數(shù)量，當(dāng)它們被安排在一樣或相反的方式上。燃燒器的數(shù)量可能暫時(shí)與爐的深度af聯(lián)系（同時(shí)=idem），此時(shí)用公式。</p><p>　　應(yīng)當(dāng)

71、指出的是，在軸上的兩個(gè)相對(duì)的空氣噴嘴，（=1）—其中一個(gè)安排在反向表面—不得傾向下調(diào)超過(guò)50度。</p><p>　　有關(guān)爐裝備，有一個(gè)很有名的案例。通過(guò)噴射用來(lái)制造一個(gè)很大的漩渦，用來(lái)覆蓋爐裝置的大部分體積，這種裝置是在爐膛四角布置燃燒器。這種裝備已經(jīng)結(jié)合研磨鼓風(fēng)機(jī)得到了廣泛的采用。然而，帶有線路和小的當(dāng)量直徑的燃燒器，經(jīng)常被用作引燃水份含量較高的低熱量褐煤。結(jié)果，以不同的速度噴射空氣粉塵混合物和從各自不同通道

72、出去的二級(jí)空氣（w2/w1 = 2–3），這些噴射物形成漩渦從而失去可以遠(yuǎn)距噴射的能力。因此，火焰接近于水壁，后者被殘?jiān)廴?。有一種方法能夠使切向燃燒方案得到改進(jìn)，這種方法是引導(dǎo)所謂的“軸心”吸納大量的空氣粉塵混合物與二次空氣，燃料和空氣噴嘴彼此不相鄰并配有通風(fēng)機(jī)。盡管火焰的溫度會(huì)下降，燃燒卻依然穩(wěn)定，這時(shí)因?yàn)槿剂虾涂諝獾幕旌线^(guò)程是在一個(gè)循序漸進(jìn)的水平上進(jìn)行的。</p><p>　　帶有大渦輪橫向旋轉(zhuǎn)軸，和主要?dú)?/p>

73、流方向有關(guān)的渦爐設(shè)計(jì)具有廣泛的可能性用于控制爐進(jìn)程。四個(gè)可控火焰的鍋爐計(jì)劃被記述，它們遵循大型噴嘴彼此相噴射的原理，這其中的三個(gè)計(jì)劃已經(jīng)被實(shí)施了。一個(gè)蒸汽能力230噸/小時(shí)的鍋爐已按照其中的一個(gè)計(jì)劃進(jìn)行了改裝（帶有反轉(zhuǎn)爐）。這種鍋爐的測(cè)試表明了，在爐子的出口處，氣體的溫度在沿爐子的深度和寬度上都是不均勻分布的。在此期間，空氣粉塵混合物在高濃縮除塵機(jī)的作用下，以25-30米/秒的速度從爐子的前沿噴射。一個(gè)測(cè)量爐中火焰高度的簡(jiǎn)單辦法是在操作

74、鍋爐的過(guò)程中進(jìn)行，這需要考慮通過(guò)爐前后方噴嘴不斷變化的空氣流量比率；這個(gè)過(guò)程允許由干底模式替換為液態(tài)排渣模式，反之亦然。一個(gè)底噴爐計(jì)劃已經(jīng)在鍋爐產(chǎn)業(yè)上得到了廣泛的應(yīng)用，這一類鍋爐配有不同的燃燒器和粉碎器。蒸汽能力從50--1650噸/小時(shí)這樣的氣動(dòng)方案鍋爐已經(jīng)被ZiO 和 Sibener gomash制造，并在俄羅斯等一些國(guó)外的發(fā)電站得到應(yīng)用。 我們必須指出，迄今為止?fàn)t的過(guò)程控制效率問(wèn)題已經(jīng)受到關(guān)注，以下兩個(gè)氣動(dòng)爐方案格外有趣：反轉(zhuǎn)模式

75、和底噴爐模式。在這種爐燃燒低質(zhì)煤的過(guò)程中，流量和爐的進(jìn)程計(jì)算分析被提出。</p><p>　　下面，其他兩個(gè)控制爐過(guò)程的技術(shù)被考慮。帶有火焰控制爐的鍋爐已經(jīng)在電力工業(yè)中得到了應(yīng)用，由于在它們的內(nèi)部存在兩個(gè)區(qū)，這些設(shè)備可以被看做在某種程度上具有可控性。各種不同的燃料可以很容易的放到一個(gè)爐內(nèi)一同燃燒。計(jì)算這種爐的例子已經(jīng)在書(shū)中第二頁(yè)給出了。至于大容量鍋爐，雙爐區(qū)控制的鍋爐發(fā)展的一直很緩慢。發(fā)展?fàn)t技術(shù)所用到的所謂VIR

76、技術(shù)（音譯縮寫(xiě)俄羅斯引進(jìn)，創(chuàng)新和改造），可以被視為這方面的曙光。那些致力于把這一技術(shù)帶進(jìn)國(guó)家行業(yè)標(biāo)準(zhǔn)中的人，遇到了自然運(yùn)作方面的麻煩（過(guò)程控制中也介紹了某些問(wèn)題）。我們認(rèn)為，這些困難是由于這樣一個(gè)事實(shí)，即燃料的分配比例超過(guò)一定分?jǐn)?shù)，導(dǎo)致可以優(yōu)化程度有限，流體在主爐容體中有著相當(dāng)緩慢的空氣動(dòng)力學(xué)結(jié)構(gòu)。還應(yīng)該指出，在冷窗下的噴床，用于噴射固體燃料粗糙組分的設(shè)備，還遠(yuǎn)遠(yuǎn)不夠完善。離心除塵技術(shù)已經(jīng)在點(diǎn)燃高活性煤炭方面得到了應(yīng)用，在這一計(jì)劃中，采