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渣漿泵脫硫煙氣檔板的概述
一、概述
為了保證FGD的停運，不影響發(fā)電機組的正常運行，在煙道上分別設(shè)置了原煙氣擋板門、凈煙氣擋板門和旁路煙氣擋板門。煙氣擋板門一般采用雙百葉窗形式。其作用主要是隔離設(shè)備、控制煙氣流量和排空煙氣。
原煙氣擋板門設(shè)在增壓風(fēng)機之前，在啟動FGD時開啟，F(xiàn)GD停運時關(guān)閉:旁路擋板門設(shè)在煙囪之前的凈煙道和原煙道之間，在啟動FGD時，旁路擋板關(guān)閉，將煙氣切換至脫硫系統(tǒng)。FGD停止或故障狀態(tài)時快速開啟。
脫硫系統(tǒng)故障時，為了保證鍋爐機組風(fēng)煙系統(tǒng)的正常運行，三個擋板門設(shè)連鎖保護(hù)。當(dāng)FGD裝置運行時，煙道旁路擋板門關(guān)閉；FGD裝置停運時，旁路門打開，F(xiàn)GD裝置進(jìn)出口擋板門關(guān)閉，煙氣通過旁路擋板門進(jìn)入煙囪，由煙囪直接排入大氣。在調(diào)試中，旁路擋板一般要放在微開位置。
二、煙氣擋板門
通常，由于對隔離擋板和煙氣流量控制擋板有不同的運行要求。FGD裝置的煙氣擋板有單百葉窗式、雙百葉窗式和閘板門三種類型。
1.百葉窗擋板門
百葉窗擋板門有單百葉窗和雙百葉窗兩種類型，由本體、一系列平行的葉片、軸密封、驅(qū)動機構(gòu)和控制部分構(gòu)成，如圖4-10和圖4-11所示。
百葉窗擋板門的葉片通過外部聯(lián)動機構(gòu)連接在一起，多數(shù)情況下由一個電動機來驅(qū)動所有葉片旋轉(zhuǎn)。也有的將百葉窗式旁路擋板門的葉片分成2-3組，分別由2-3個執(zhí)行機構(gòu)驅(qū)動，其目的是在FGD系統(tǒng)啟動、關(guān)閉旁路擋板時最大限度地降低對護(hù)膛壓力的影響；在需要快速開啟旁路門時，降低所有葉片不能開啟的風(fēng)險。
百葉窗擋板門的每個葉片的邊緣一般都設(shè)計有需封條，在擋板門關(guān)閉時起葉片之間相互密封作用。門框的密封(他叫側(cè)面密封)布置在葉片兩端的門框邊緣上，側(cè)面密封是防止煙氣從葉片兩端泄漏。采用雙百葉窗擋板門可以進(jìn)一步提高密封性能，除了每層擋板上配備密封元件外，在兩層擋板門中間還通入密封空氣。當(dāng)雙百葉窗擋板門關(guān)閉時，兩層擋板門中間通入的密封空氣，能阻止煙氣由擋板門一側(cè)泄漏到另一側(cè)，如圖4-11所示。
擋板密封空氣系統(tǒng)包括密封風(fēng)機、密封風(fēng)加熱器、檢測儀表、調(diào)節(jié)設(shè)備及其管路等。一般每套FGD配兩臺密封風(fēng)機，2X100%容量，一臺運行一臺備用。
入口、出口擋板門的密封空氣和旁路擋板門的密封空氣不同時運行。不同擋板密封風(fēng)的切換通過裝在擋板門上的閥門來實現(xiàn)，該與擋板門為機械連鎖。
密封空氣壓力維持比煙氣最高壓力至少高500-700Pa，因此風(fēng)機必須設(shè)計有是夠的容量和壓頭。
密封空氣加熱器有電加熱和蒸汽加熱兩種形式，密封空氣加熱器加熱至100°C有左右，減少與煙氣之間的溫差，使擋板門的變形控制在允許范圍內(nèi)。
2. 閘板式擋板門
閘板式擋板門簡稱閘板門，如圖4-12所示，
當(dāng)閘板從煙道內(nèi)完全抽出時，煙道全開，當(dāng)閘板完全落入煙道時，煙道關(guān)閉。這是一種零泄漏的擋板門，檢修人員在其下游工作，能保障人身安全，
閘板順著擋板門框架的內(nèi)側(cè)插入到周圍有空氣密封的密封室內(nèi)。噴入密封室的空氣壓力要大于煙氣側(cè)壓力，以防止煙氣漏入密封空氣室。擋板框架內(nèi)側(cè)的擋板槽內(nèi)裝有密封薄片，以減少密封空氣的用量，當(dāng)閘板被提升起來時，密封片緊靠在一起。
擋板在煙道中提升和落下，最常用的方法是在擋板上部兩端裝有固定的鏈條，用一個鏈條驅(qū)動裝置來提升擋板。根據(jù)擋板的尺寸和質(zhì)量，一般用2~4根鏈條。另一種提升方法是用齒輪驅(qū)動機構(gòu)沿?fù)醢鍍蓚?cè)的齒條提升擋板。
閘板門和雙百葉窗擋板隔斷性好，但占據(jù)的空間大，造價高。渣漿泵
Overview of FGD baffle plate of slurry pump
I. overview
In order to ensure the shutdown of FGD and not affect the normal operation of the generator set, the original flue gas damper, net flue gas damper and bypass flue gas damper are set on the flue. The flue gas baffle door is generally in the form of double leaf windows. Its main functions are to isolate equipment, control flue gas flow and exhaust flue gas.
The original flue gas damper is set in front of the booster fan, which is opened when the FGD is started and closed when the FGD is stopped: the bypass damper is set between the clean flue and the original flue in front of the chimney. When the FGD is started, the bypass damper is closed to switch the flue gas to the desulfurization system. FGD stop or fast start in fault state.
When the desulfurization system fails, in order to ensure the normal operation of the air and flue gas system of the boiler unit, three damper doors are provided with interlock protection. When FGD device is running, bypass damper valve of flue is closed; when FGD device is stopped, bypass valve is opened, inlet and outlet damper valve of FGD device is closed, flue gas enters chimney through bypass damper valve, and is directly discharged into atmosphere from chimney. During commissioning, the bypass damper shall be generally placed at the slightly open position.
II. Flue gas damper
Generally, there are different operation requirements for the isolation damper and the flue gas flow control damper. There are three types of flue gas damper in FGD device: single shutter type, double shutter type and gate type.
1. Shutter baffle door
There are two types of shutter door: single shutter and double shutter, which are composed of body, a series of parallel blades, shaft seal, driving mechanism and control part, as shown in Fig. 4-10 and Fig. 4-11.
The blades of the shutter door are connected by an external linkage mechanism, and in most cases, all blades are driven by a single motor. In some cases, the blades of the shutter bypass damper door are divided into 2-3 groups, which are driven by 2-3 actuators respectively. The purpose is to minimize the impact on the chamber pressure when the FGD system starts and closes the bypass damper, and reduce the risk that all blades cannot be opened when the bypass valve needs to be opened quickly.
The edge of each blade of the shutter baffle door is generally designed with sealing strip, which plays the role of mutual sealing between blades when the baffle door is closed. The sealing of the door frame (called side sealing) is arranged on the edge of the door frame at both ends of the blade. The side sealing is to prevent the smoke from leaking from both ends of the blade. The sealing performance can be further improved by adopting double shutter baffle doors. In addition to the sealing elements on each baffle, the sealing air is also introduced into the middle of the two baffle doors. When the double shutter baffle door is closed, the sealing air in the middle of the two-layer baffle door can prevent smoke from leaking from one side of the baffle door to the other side, as shown in Figure 4-11.
The baffle seal air system includes seal fan, seal air heater, testing instrument, regulating equipment and pipeline, etc. Generally, each set of FGD is equipped with two seal fans with capacity of 2x100%, one for operation and one for standby.
The sealing air of the inlet and outlet damper doors and the sealing air of the bypass damper doors do not operate at the same time. The switching of different baffle seal air is realized by the valve installed on the baffle door, which is mechanically interlocked with the baffle door.
The seal air pressure is maintained at least 500-700pa higher than the maximum pressure of flue gas, so the fan must be designed with enough capacity and pressure head.
There are two types of sealed air heater: electric heating and steam heating. When the sealed air heater is heated to 100 ° C, the temperature difference between the sealed air heater and the flue gas will be reduced, and the deformation of the baffle door will be controlled within the allowable range.
2. Gate type damper door
Gate type damper door is referred to as gate plate door, as shown in Figure 4-12.
When the ram is fully drawn out from the flue, the flue is fully open, and when the ram is completely dropped into the flue, the flue is closed. This is a kind of zero leakage baffle door. The maintenance personnel can work in its downstream to ensure personal safety.
The ram is inserted along the inner side of the damper door frame into the surrounding airtight seal chamber. The air pressure injected into the seal chamber shall be greater than the pressure at the flue gas side to prevent the flue gas from leaking into the seal air chamber. The baffle groove inside the baffle frame is equipped with sealing sheet to reduce the amount of sealing air. When the ram is lifted, the sealing sheet is close together.
The most common way to lift and lower the baffle in the flue is to install a fixed chain at both ends of the upper baffle, and use a chain drive device to lift the baffle. According to the size and quality of baffle, 2-4 chains are generally used. Another lifting method is to use a gear driving mechanism to lift the baffle along the rack on both sides of the baffle.
Gate and double shutter baffle have good partition, but they occupy a large space and cost a lot. Slurry pump
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