三組換向閥與RT0三個蓄熱室對應(yīng)，通過一定的順序打開、關(guān)閉，引導(dǎo)煙氣通過蓄熱室、燃燒室，最終排放到大氣中。工作時RTO焚燒爐內(nèi)呈微負(fù)壓狀態(tài)。高溫側(cè)換向閥的外側(cè)與煙氣出口管道連通，區(qū)域溫度最高達(dá)300°C;低溫側(cè)換向閥的外側(cè)與煙氣進(jìn)口管道連通，區(qū)域溫度最高達(dá)200°C。爐內(nèi)廢氣具有一定的腐蝕性。裝置運行時，換向閥每60-180s開閉一次，動作頻繁。

Three sets of directional valves correspond to the three heat storage chambers of RT0, which are opened and closed in a certain order to guide the flue gas through the heat storage chamber and combustion chamber, and finally discharged into the atmosphere. During operation, the RTO incinerator is in a slightly negative pressure state. The outer side of the high-temperature side directional valve is connected to the flue gas outlet pipeline, with a maximum temperature of 300 ° C in the area; the outer side of the low-temperature side directional valve is connected to the flue gas inlet pipeline, with a maximum temperature of 200 ° C. The exhaust gas in the furnace has a certain degree of corrosiveness. During device operation, the directional valve opens and closes frequently every 60-180 seconds.

換向閥的平面閥板與密封端面通過直接接觸實現(xiàn)密封。閥板閉合后，因加工、裝配精度低導(dǎo)致密封不嚴(yán)，廢氣在壓力作用下流動，在閥板處形成少許內(nèi)漏，不通過蓄熱體及爐瞠焚燒直接排放。同時，閥桿在往復(fù)運動中對密封填料造成磨損，使廢氣通過填料直接泄漏到大氣中，發(fā)生外漏。

The flat valve plate of the directional valve is sealed by direct contact with the sealing end face. After the valve plate is closed, the sealing is not tight due to low processing and assembly accuracy, and the exhaust gas flows under pressure, forming a small internal leakage at the valve plate, which is directly discharged without passing through the heat storage body and furnace combustion. At the same time, the valve stem causes wear on the sealing packing during reciprocating motion, causing exhaust gas to leak directly into the atmosphere through the packing, resulting in external leakage.

另外，換向閥內(nèi)部存在高溫?zé)煔猓?jīng)長期運行后，原閥桿與閥板均存在不同程度的腐蝕損壞。由于原換向閥設(shè)計存在上述問題，加之在排放指標(biāo)、環(huán)保指標(biāo)更為嚴(yán)格的情況下，即使少量的泄漏也會對排放指標(biāo)產(chǎn)生很大的影響，因此需要通過改造提高閥門的密封性、耐蝕性和耐用度，使裝置能夠滿足現(xiàn)有工況條件下長期穩(wěn)定運行的要求，并且使排放的廢氣滿足《GB31571-2015石油化學(xué)工業(yè)污染物排放標(biāo)準(zhǔn)》的排放指標(biāo)。

In addition, there is high-temperature flue gas inside the directional valve, and after long-term operation, the original valve stem and valve plate have varying degrees of corrosion damage. Due to the aforementioned issues with the original directional valve design and the stricter emission and environmental standards, even a small amount of leakage can have a significant impact on the emission indicators. Therefore, it is necessary to improve the sealing, corrosion resistance, and durability of the valve through modification, so that the device can meet the requirements of long-term stable operation under existing working conditions, and the emitted exhaust gas can meet the emission indicators of the "GB31571-2015 Petrochemical Industry Pollutant Emission Standard".

根據(jù)長期運行后裝置換向閥出現(xiàn)的泄露、損壞等問題，結(jié)合故障點的出現(xiàn)位置，可以從以下三個方面對換向閥的結(jié)構(gòu)進(jìn)行分析，并考慮改進(jìn)辦法:

Based on the leakage and damage of the reversing valve after long-term operation, combined with the location of the fault point, the structure of the reversing valve can be analyzed from the following three aspects and improvement methods can be considered:

1.閥桿材料及其連接結(jié)構(gòu)換向閥的主要動件是閥桿和圓形閥板，因閥門動作頻繁，密封結(jié)構(gòu)及支撐結(jié)構(gòu)負(fù)荷較大。加之爐中廢氣溫度較高且有較強(qiáng)的腐蝕性，裝置運行一段時間后，閥桿與閥板均發(fā)生了一定的磨損與破壞。

The main moving parts of a directional valve are the valve stem and circular valve plate. Due to frequent valve movements, the sealing and supporting structures are heavily loaded. In addition, the exhaust gas in the furnace has a high temperature and strong corrosiveness, and after running the device for a period of time, both the valve stem and valve plate have suffered certain wear and damage.

經(jīng)現(xiàn)場測量、檢查發(fā)現(xiàn)，閥板與密封面之間存在一定程度的平行度偏差。因此，應(yīng)對閥板與閥桿采取降低重量、更換材料、增加錯動補(bǔ)償機(jī)構(gòu)等措施使動件擁有更長的使用壽命和更好的密封效果。

After on-site measurement and inspection, it was found that there is a certain degree of parallelism deviation between the valve plate and the sealing surface. Therefore, measures such as reducing weight, replacing materials, and adding misalignment compensation mechanisms should be taken for the valve plate and stem to ensure that the moving parts have a longer service life and better sealing effect.

2.閥板密封結(jié)構(gòu)原設(shè)計中，圓形閥板僅通過與密封面接觸時自身發(fā)生形變來進(jìn)行密封。

In the original design of the valve plate sealing structure, the circular valve plate only seals by deforming itself when in contact with the sealing surface.

由于加工精度無法保證，以及長期運行帶來的支撐結(jié)構(gòu)磨損，圓形閥板與密封面無法在圓周上所有的位置都能緊密接觸。因此，需要對閥板密封結(jié)構(gòu)進(jìn)行重新設(shè)計，來保證長期運行中閥板密封的可靠性。

Due to the inability to guarantee machining accuracy and the wear of supporting structures caused by long-term operation, the circular valve plate and sealing surface cannot be in close contact at all positions on the circumference. Therefore, it is necessary to redesign the valve plate sealing structure to ensure the reliability of valve plate sealing during long-term operation.

3.閥桿密封結(jié)構(gòu)及支撐結(jié)構(gòu)原設(shè)計中，閥桿的密封組件采用的是填料式密封，由于換向閥的動作頻率非常高(每60-180s動作1次)使得此處密封填料的損耗非常快。

In the original design of the valve stem sealing structure and support structure, the sealing component of the valve stem used a packing type seal. Due to the high operating frequency of the directional valve (once every 60-180s), the loss of sealing packing in this area is very fast.