一、氣力輸送輸送過程

　　1、 Pneumatic conveying process

　　本系統(tǒng)采用倉泵間歇式輸送方式，每輸送一泵飛灰，即為一個工作循環(huán)。每個工作循環(huán)分四個階段。

　　This system adopts the intermittent conveying mode of the bin pump, and each pump of fly ash conveyed is a working cycle. Each work cycle is divided into four stages.

　　1.進料階段

　　1. Feeding stage

　　進料閥呈開啟狀態(tài)，進氣閥和出料閥關(guān)閉，倉泵內(nèi)部與灰斗連通;?倉泵內(nèi)無壓力(與除塵器內(nèi)部等壓），飛灰源源從除塵器灰斗進入倉泵，當倉泵內(nèi)飛灰灰位高至與料位計探頭接觸，則料位計產(chǎn)生一料滿信號，并通過現(xiàn)場控制單元進入程序控制器。在程序控制器控制下，系統(tǒng)自動關(guān)閉進料閥，進料狀態(tài)結(jié)束。

　　The inlet valve is in the open state, the inlet valve and outlet valve are closed, and the interior of the bin pump is connected to the ash hopper;? There is no pressure inside the bin pump (equal pressure to the inside of the dust collector), and the fly ash source enters the bin pump from the dust collector hopper. When the fly ash level in the bin pump is high enough to contact the level gauge probe, the level gauge generates a full signal and enters the program controller through the on-site control unit. Under the control of the program controller, the system automatically closes the feeding valve and the feeding state ends.

　　2.加壓流化階段

　　2. Pressure fluidization stage

　　進料閥關(guān)閉后，打開進氣閥，壓縮空氣通過流化盤均勻進入倉泵，倉泵內(nèi)飛灰充分流態(tài)化，同時?壓力升高，當壓力高至壓力表?上限壓力時，則雙壓力開關(guān)輸出上限壓力信號至控制系統(tǒng)，系統(tǒng)自動打開出料閥，加壓流態(tài)化階段結(jié)束，進入輸送階段。

　　After the feed valve is closed, open the intake valve, and compressed air enters the bin pump evenly through the fluidized disc. The fly ash in the bin pump is fully fluidized, and at the same time? When the pressure rises to the pressure gauge? When the upper limit pressure is reached, the dual pressure switch outputs the upper limit pressure signal to the control system. The system automatically opens the discharge valve, and the pressurized fluidization stage ends, entering the conveying stage.

　　3.輸送階段

　　3. Transportation stage

　　出料閥打開，此時倉泵邊繼續(xù)進氣，一邊氣灰混和物通過出料閥進入輸灰管道，并輸送至灰?guī)臁．攤}泵內(nèi)飛灰輸送完后，管路阻力下降，倉泵內(nèi)壓力降低:當倉泵內(nèi)壓力降低至雙壓力開關(guān)整定的下限壓力時，輸送階段結(jié)束，進入吹掃階段，但此時進氣和出料閥仍保持開啟狀態(tài)。

　　The discharge valve is opened, and the bin pump continues to intake air while the gas ash mixture enters the ash conveying pipeline through the discharge valve and is transported to the ash silo. After the fly ash is transported in the bin pump, the pipeline resistance decreases and the pressure inside the bin pump decreases: when the pressure inside the bin pump decreases to the lower limit pressure set by the dual pressure switch, the conveying stage ends and enters the purging stage, but the inlet and outlet valves remain open at this time.

　　4.吹掃階段

　　4. Purging stage

　　進氣和出料閥仍開啟，壓縮空氣吹掃倉泵和輸灰管道。定時一段時間后，吹掃結(jié)束，關(guān)閉進氣閥、出料閥，然后打開進料閥，倉泵恢復(fù)到進料狀態(tài)。至此，包括四個階段的一個輸送循環(huán)結(jié)束，重新開始下一個輸送循環(huán)。

　　The intake and discharge valves are still open, and compressed air is used to blow the bin pump and ash conveying pipeline. After a certain period of time, the blowing is completed, the inlet valve and outlet valve are closed, and then the inlet valve is opened, and the bin pump returns to the feeding state. At this point, one conveying cycle consisting of four stages ends, and the next conveying cycle begins again.

　　六、輸送流態(tài)

　　6、 Transport flow state

　　1.倉泵內(nèi)流態(tài)

　　1. Flow state inside the bin pump

　　a.加壓流化階段

　　a. Pressure fluidization stage

　　進料閥和出料閥都關(guān)閉，壓縮空氣通過流化盤進入倉泵。倉泵下錐體內(nèi)飛灰呈均勻流態(tài)化，灰氣充分混和，同時倉泵內(nèi)壓力升高，此時如同一壓力流化床。

　　Both the inlet and outlet valves are closed, and compressed air enters the bin pump through the fluidized bed. The fly ash in the lower cone of the silo pump is uniformly fluidized, and the ash gas is fully mixed. At the same time, the pressure inside the silo pump increases, and it is like a pressure fluidized bed.

　　b.輸送階段

　　b. Transportation stage

　　出料閥呈開啟狀態(tài)，灰氣混和物進入輸灰管道，同時壓縮空?氣通過流化盤進入倉泵。倉泵下錐體?內(nèi)出料管端附近局部繼續(xù)呈急劇流態(tài)化，飛灰一邊被流態(tài)化，?灰氣均勻混合，邊均勻進入輸灰管道實現(xiàn)飛灰的遠距離輸送。此時倉泵內(nèi)壓力保持穩(wěn)定。

　　The discharge valve is in the open state, and the ash gas mixture enters the ash conveying pipeline while compressing the air? Gas enters the bin pump through the fluidized bed. The lower cone of the warehouse pump? The area near the inner discharge pipe end continues to exhibit rapid fluidization, while the fly ash is fluidized on one side,? The ash gas is evenly mixed and enters the ash conveying pipeline uniformly to achieve long-distance transportation of fly ash. At this time, the pressure inside the warehouse pump remains stable.

　　c.吹掃階段

　　c. Blowing stage

　　此時倉泵內(nèi)已無飛灰，管道內(nèi)飛灰逐步減少，最后呈純空氣流動狀態(tài)。系統(tǒng)阻力下降，倉泵內(nèi)壓力也下降至穩(wěn)定值。吹掃的目的是吹盡管路和泵體內(nèi)殘留的飛灰，以利于下一循環(huán)的輸送。

　　At this point, there is no fly ash in the warehouse pump, and the fly ash in the pipeline gradually decreases, finally reaching a pure air flow state. The system resistance decreases, and the pressure inside the bin pump also drops to a stable value. The purpose of purging is to blow away the residual fly ash in the pipeline and pump body, in order to facilitate the transportation of the next cycle.

　　d.管道流態(tài)

　　d. Flow state of pipeline

　　從管道流態(tài)上看，本系統(tǒng)采用了正壓濃相流態(tài)技術(shù)。管道前端呈旁路濃相流態(tài)，管道后端由于壓?氣體膨脹，?速度提高而轉(zhuǎn)變?yōu)檫B續(xù)濃相流態(tài)。

　　From the perspective of pipeline flow state, this system adopts positive pressure dense phase flow technology. The front end of the pipeline is in a bypass dense phase flow state, while the back end of the pipeline is affected by pressure? Gas expansion, right,? As the speed increases, it transforms into a continuous dense phase flow state.

　　e.旁路濃相流態(tài)

　　e. Bypass dense phase flow state

　　旁路濃相流態(tài)輸送濃度高[灰氣比可達30- 60Kg/Kg]，同時速度低[根據(jù)輸送物料，在5~10m/s之間]。

　　The bypass dense phase flow transport has high concentration [ash to gas ratio can reach 30-60Kg/Kg], while the speed is low [between 5-10m/s depending on the transported material].

　　在水平管道內(nèi)，由于流速較低，飛灰在重力作用下沉降管底?，造成上部流道縮小，上部流道內(nèi)氣流速度增加，又帶動飛灰重新飛揚，如此反復(fù)，同時下部沉降飛灰在壓力作用下呈滑移狀態(tài)，故是一種動壓和靜壓同時作用的流態(tài)。此流態(tài)具有輸送效率高、耗氣量少、流動速度低、對管道磨損小等優(yōu)點。

　　In a horizontal pipeline, due to the low flow velocity, fly ash settles at the bottom of the pipe under the action of gravity? This causes the upper flow channel to shrink, the airflow velocity inside the upper flow channel to increase, and drives the fly ash to fly again, repeating this process. At the same time, the lower settling fly ash is in a sliding state under pressure, resulting in a flow state where both dynamic and static pressure act simultaneously. This flow state has the advantages of high transport efficiency, low gas consumption, low flow velocity, and minimal wear on pipelines.

　　f.連續(xù)濃相流態(tài)

　　f. Continuous dense phase flow state

　　輸送管道后端由于壓力減小，氣體膨脹，導(dǎo)致流動速度提高，流態(tài)也轉(zhuǎn)變?yōu)檫B續(xù)濃相。連續(xù)濃相流態(tài)輸送濃度高，同時速度也較大，為此可采用逐段擴徑以減小磨損。

　　Due to the decrease in pressure and gas expansion at the rear end of the conveying pipeline, the flow velocity increases and the flow state changes to a continuous dense phase. Continuous dense phase flow conveying has high concentration and high speed, so it is possible to use step-by-step diameter expansion to reduce wear.

　　如圖所示，由于管道內(nèi)流動的壓縮空氣減壓膨脹，輸送速度提高，飛灰基本均勻懸浮在管道截面上，在氣流的動壓帶動下穩(wěn)定流動。

　　As shown in the figure, due to the decompression and expansion of the compressed air flowing inside the pipeline, the conveying speed is increased, and the fly ash is basically uniformly suspended on the cross-section of the pipeline, and flows steadily under the dynamic pressure of the airflow.

　　二、氣力輸送系統(tǒng)性能分析及特點

　　2、 Performance analysis and characteristics of pneumatic conveying system

　　濃相正壓氣力輸灰系統(tǒng)是結(jié)合流態(tài)化和管道二相流技術(shù)研制的，采用動壓與靜壓聯(lián)合輸送方式的高濃度、高效率飛灰輸送設(shè)備。系統(tǒng)整體性能指標大大超過常規(guī)的稀相輸送系統(tǒng)，是目前世界上先進的氣力輸送技術(shù)。其系統(tǒng)性能和特點具體說有以下幾個方面。

　　The dense phase positive pressure pneumatic ash conveying system is a high concentration and high-efficiency fly ash conveying equipment developed by combining fluidization and two-phase flow technology in pipelines, using a combination of dynamic and static pressure conveying methods. The overall performance indicators of the system greatly exceed those of conventional dilute phase conveying systems, and it is currently the world's advanced pneumatic conveying technology. Specifically, its system performance and characteristics include the following aspects.

　　1.較高的灰氣比

　　1. Higher ash to gas ratio

　　灰氣比可達30?~ 60Kg/Kg,而常規(guī)稀相系統(tǒng)為5 ~ 15Kg/Kg。因此其空氣耗量大為減小，在大多數(shù)情況下，濃相正壓氣力輸灰系統(tǒng)的空氣消耗量約為其它系統(tǒng)的1/3 ~ 1/2。由此帶來一系列有利的因素:

　　Can the ash to gas ratio reach 30? ~ 60Kg/Kg, And the conventional dilute phase system is 5-15Kg/Kg. Therefore, its air consumption is greatly reduced. In most cases, the air consumption of the dense phase positive pressure pneumatic ash conveying system is about 1/3 to 1/2 of that of other systems. This brings a series of favorable factors:

　　a.供氣不必使用大型空氣壓縮機，因而可采用性能可靠的小型螺桿式空壓機。供氣系統(tǒng)投資較低，為使系統(tǒng)更加可靠穩(wěn)定，在壓縮空氣站增加套壓縮空氣干燥過濾系統(tǒng)在經(jīng)濟上也是允許的。

　　a. Gas supply does not require the use of large air compressors, therefore reliable small screw air compressors can be used. The investment in the gas supply system is relatively low. In order to make the system more reliable and stable, it is economically feasible to add a compressed air drying and filtering system to the compressed air station.

　　b.輸灰系統(tǒng)輸送入貯灰?guī)斓臍饬枯^小，因而貯灰?guī)焐系牟即^濾器排負荷大大降低，從而有利于布袋過濾器的長期可靠運行。通常由于貯灰?guī)焖柽^濾的空氣量大，而貯灰?guī)祉摬康目臻g較小，往往造成在高比負荷下運行的布袋過早損壞。而本系統(tǒng)較好地解決了這一難題。

　　b. The amount of air transported by the ash conveying system into the ash storage bin is relatively small, so the discharge load of the bag filter on the ash storage bin is greatly reduced, which is conducive to the long-term reliable operation of the bag filter. Usually, due to the large amount of air that needs to be filtered in the ash storage bin and the small space in the ash storage bin, it often leads to premature damage of the bag operated under high specific load. And this system has effectively solved this problem.

　　c.在通過提高濃度滿足出力的前提下，所用管道口徑大為減小，常用DN65、DN80、DN100、 DN125等小口徑管道而稀相系統(tǒng)管道口徑一般在DN125 DN250之間。由于管道口徑減小，因而管道自重和沖擊力較小，可選用輕型支架或利用現(xiàn)有廠房建筑敷設(shè)安裝，十分方便，且投資要比常規(guī)稀相系統(tǒng)低得多。

　　c. Under the premise of increasing the concentration to meet the output, the diameter of the pipeline used is greatly reduced. Small diameter pipelines such as DN65, DN80, DN100, DN125 are commonly used, while the diameter of pipelines in dilute phase systems is generally between DN125 and DN250. Due to the reduced diameter of the pipeline, its own weight and impact force are relatively small. Lightweight supports or existing factory buildings can be used for installation, which is very convenient and requires much lower investment than conventional dilute phase systems.

　　2.較低的輸送流速

　　2. Lower conveying flow rate

　　在通過提高濃度滿足出力的前提下，盡可能降低輸送流速以減少磨損。本系統(tǒng)平均流速在8 ~ 12m/s,而起始段流速為5~8m/s, 為常規(guī)稀相系統(tǒng)的一半左右，因此輸灰管道磨損大為減少。管道?磨損小，就可不用昂貴的耐磨管而采用普通無縫鋼管即可，?只在彎頭部位采用耐磨材料或增加壁厚。

　　On the premise of increasing the concentration to meet the output, try to reduce the conveying flow rate as much as possible to minimize wear. The average flow velocity of this system is 8~12m/s, while the initial flow velocity is 5~8m/s, which is about half of the conventional dilute phase system. Therefore, the wear of the ash conveying pipeline is greatly reduced. The Conduit? If the wear is small, ordinary seamless steel pipes can be used instead of expensive wear-resistant pipes,? Only use wear-resistant materials or increase wall thickness in the elbow area.

　　3.較高的工作壓力

　　3. Higher work pressure

　　系統(tǒng)工作壓力較高，一般為2~4Kg/cm2, 對設(shè)備密封性要求較嚴。但可充分利用常規(guī)空壓機提供的壓頭。且由于其流量大為減小，故足以抵消壓力增高所增加的費用。

　　The working pressure of the system is relatively high, generally ranging from 2 to 4Kg/cm2, and there are strict requirements for equipment sealing. But it can fully utilize the pressure head provided by conventional air compressors. And due to its significantly reduced flow rate, it is sufficient to offset the increased cost caused by increased pressure.

　　4較好工作適應(yīng)范圍

　　4. Good job adaptability range

　　輸送距離范圍寬廣，從短距離的50米至1500米長距離，?本系統(tǒng)都有其良好的輸送記錄。對于更長距離的輸送，可采用中間站接力的方式解決，如一級輸送采用小型倉泵把飛灰集中至中間轉(zhuǎn)運灰?guī)欤壿斔陀么笮蛡}泵遠距離輸送至終端主灰?guī)臁?/p>

　　The conveying distance range is wide, from short distances of 50 meters to long distances of 1500 meters,? This system has a good delivery record. For longer distance transportation, intermediate station relay can be used to solve the problem. For example, small bin pumps are used for primary transportation to concentrate fly ash in the intermediate transfer ash silo, while large bin pumps are used for secondary transportation to transport it over long distances to the terminal main ash silo.

　　5.與除塵器的協(xié)調(diào)性

　　5. Coordination with dust collectors

　　倉泵與除塵器灰斗直接連通，正常工作情況下，灰斗內(nèi)僅僅在相應(yīng)倉泵處于輸送狀態(tài)時才有少量積灰，因而灰斗般可不設(shè)加熱和氣化設(shè)備，并大大有利于除塵器的運行。

　　The bin pump is directly connected to the ash hopper of the dust collector. Under normal working conditions, there is only a small amount of ash accumulation in the ash hopper when the corresponding bin pump is in the conveying state. Therefore, the ash hopper generally does not need heating and gasification equipment, which greatly facilitates the operation of the dust collector.

　　5.安裝維修方便

　　5. Easy installation and maintenance

　　由于倉泵體積小重量輕，故安裝方便，維修也容易。常用倉泵規(guī)格為0.25 ~ 2.5m3,重量在250~1500Kg之間，可直接吊掛在灰斗下。

　　Due to its small size and light weight, the warehouse pump is easy to install and maintain. The commonly used bin pump specifications are 0.25~2.5m3, with a weight between 250~1500Kg, and can be directly hung under the ash hopper.

　　7.配置靈活

　　7. Flexible configuration

　　本系統(tǒng)配置靈活方便，可根據(jù)出力需要靈活配置倉泵規(guī)格、輸灰管道連接方式，以適應(yīng)實際工況要求。

　　This system is flexible and convenient to configure, and can flexibly configure the specifications of the bin pump and the connection method of the ash conveying pipeline according to the output needs to adapt to the actual working conditions.

　　8.可靠性和可維修性

　　8. Reliability and maintainability

　　本系統(tǒng)在設(shè)計過程中即考慮了系統(tǒng)設(shè)備的可靠性和可維修性要求。主要體現(xiàn)在以下幾個方面:

　　The reliability and maintainability requirements of the system equipment were taken into consideration during the design process. Mainly reflected in the following aspects:

　　9.系統(tǒng)具備的故障備用方式優(yōu)越，可大大提高系統(tǒng)級可靠性和可維修性。如電除塵器一旦某一?電場下倉泵故障，即可停止此電場倉泵的輸送，而不影響其它電場倉泵工作，這對維修是有利的。對于本系統(tǒng)內(nèi)的主要動作部件，如電磁閥、氣缸，由于控制用氣經(jīng)過徹底的凈化處理，因而具有很高的可靠性。對于本系統(tǒng)內(nèi)工作工況惡劣的關(guān)鍵部件，如進料閥和出料閥等，針對高沖蝕性灰氣?相流工況進行設(shè)計和制造，以滿足其工?況適應(yīng)性和長期使用可靠性能要求，并考慮可維修性要求。對于本系統(tǒng)內(nèi)工作工況惡劣的關(guān)鍵部件，如進料閥和出料閥等，針對高沖蝕性灰氣混合二相流工況進行設(shè)計和制造，以滿足其工況適應(yīng)性和長期使用可靠性能要求，并考慮可維修性要求。

　　9. The system has superior fault backup methods, which can greatly improve system level reliability and maintainability. What if an electrostatic precipitator is used? If there is a malfunction in the electric field bin pump, the delivery of this electric field bin pump can be stopped without affecting the operation of other electric field bin pumps, which is beneficial for maintenance. For the main operating components within this system, such as solenoid valves and cylinders, due to thorough purification treatment of the control air, they have high reliability. For critical components with harsh working conditions within this system, such as feed valves and discharge valves, what is the solution for high erosive ash gas? Design and manufacture phase flow conditions to meet their requirements? Adaptability and long-term reliability performance requirements, while considering maintainability requirements. For critical components in this system that work under harsh conditions, such as feed valves and discharge valves, design and manufacture for high erosion ash gas mixed two-phase flow conditions to meet their adaptability and long-term reliability requirements, while considering maintainability requirements.

　　系統(tǒng)的大量配套件，如閥門、?氣缸、儀器儀表等都盡量采用標準元件，互換性強，維修費用低且更換方便。

　　A large number of system accessories, such as valves? Cylinders, instruments, etc. should use standard components as much as possible, with strong interchangeability, low maintenance costs, and easy replacement.

　　自動運行水平

　　Automatic operation level

　　三、氣力輸送系統(tǒng)自動化程度高，操作簡單。

　　3、 The pneumatic conveying system has a high degree of automation and is easy to operate.

　　系統(tǒng)動態(tài)顯示、故障報警和處理功能齊全。在必要的時間，既可與除塵器控制中心聯(lián)系構(gòu)成一集控中心，同時又可在本系統(tǒng)局部范圍內(nèi)[如對某一倉泵]實現(xiàn)手動操作，因此操作管理都非常靈活方便。

　　The system has complete functions of dynamic display, fault alarm, and handling. At the necessary time, it can be connected to the dust collector control center to form a centralized control center, and at the same time, manual operation can be achieved within the local scope of the system [such as for a certain bin pump], so the operation management is very flexible and convenient.

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