負(fù)壓氣力輸送設(shè)備的構(gòu)成以及如何使用

The composition of negative pressure pneumatic conveying equipment and how to use it

　　負(fù)壓氣力輸送設(shè)備通常由物料輸送閥、進(jìn)氣止回閥、輸送管道及閥門(mén)、灰氣別離設(shè)備、貯灰?guī)旒拜o佐設(shè)備、負(fù)壓風(fēng)機(jī)和操控設(shè)備等構(gòu)成。物料輸送閥又稱E形閥，作為受料器的輸送閥是負(fù)壓設(shè)備的關(guān)鍵設(shè)備之一，其作用是經(jīng)過(guò)物料輸送閥上的補(bǔ)氣閥和灰量調(diào)理設(shè)備的作業(yè)，使灰斗內(nèi)的灰與空氣均勻混合，灰氣混合物具有杰出的流動(dòng)性，可使其順暢進(jìn)入輸送管道，以確保輸送設(shè)備高效、曉暢地運(yùn)轉(zhuǎn)。物料輸送選用氣支操控，其閥體和閥具有杰出的耐磨性。

Negative pressure pneumatic conveying equipment usually consists of material conveying valves, intake check valves, conveying pipelines and valves, ash separation equipment, ash storage warehouses and auxiliary equipment, negative pressure fans and control equipment, etc. The material conveying valve, also known as the E-shaped valve, is one of the key equipment of negative pressure equipment as the conveying valve of the material receiver. Its function is to pass through the air replenishment valve on the material conveying valve and the operation of the ash volume adjustment equipment, so that the ash in the ash hopper is evenly mixed with the air. The ash air mixture has excellent fluidity, which can smoothly enter the conveying pipeline to ensure the efficient and smooth operation of the conveying equipment. The material transportation adopts pneumatic control, and its valve body and valve have outstanding wear resistance.

　　進(jìn)氣止回閥選用旋啟式構(gòu)造，當(dāng)輸送管道內(nèi)濃度過(guò)高造成輸送支管進(jìn)氣端真空值過(guò)高時(shí)，進(jìn)氣止回閥主動(dòng)打開(kāi)，補(bǔ)人適當(dāng)?shù)目諝庖韵♂屵^(guò)高的物料濃度，以避免堵管的發(fā)作。

The intake check valve adopts a rotary structure. When the concentration in the conveying pipeline is too high, causing the vacuum value at the inlet end of the conveying branch to be too high, the intake check valve actively opens, and appropriate air is added to dilute the excessive material concentration to avoid pipe blockage.

　　負(fù)壓氣力輸送系統(tǒng)指利用壓風(fēng)機(jī)（真空泵）產(chǎn)生系統(tǒng)負(fù)壓，將在受料器處與空氣均勻混合的粉粒狀物料通過(guò)管道抽送至貯料裝置的輸送系統(tǒng)，主要用于燃煤電廠的灰處理系統(tǒng)，又稱負(fù)壓氣力除灰系統(tǒng)，為國(guó)外引進(jìn)技術(shù)，其系統(tǒng)設(shè)計(jì)技術(shù)已為國(guó)內(nèi)除灰系統(tǒng)設(shè)計(jì)人員完全掌握。

The negative pressure pneumatic conveying system refers to a conveying system that uses a pressure fan (vacuum pump) to generate negative pressure in the system, and uniformly mixes powdered materials with air at the feeding device through pipelines to be transported to the storage device. It is mainly used in the ash treatment system of coal-fired power plants, also known as the negative pressure pneumatic ash removal system. It is a technology imported from abroad, and its system design technology has been fully mastered by domestic ash removal system designers.

　　負(fù)壓氣力輸送系統(tǒng)投資少，可以進(jìn)行多點(diǎn)上料、下料，要求料斗下部的凈空較小，適用于300MW及以下火電機(jī)組的除灰系統(tǒng)，且由于設(shè)備和管路在真空狀態(tài)下只能發(fā)生內(nèi)泄漏，因而環(huán)境比較清潔。缺點(diǎn)是由于負(fù)壓值有限，因而輸送距離較短，一般輸送的幾何距離為200m，實(shí)際工程宜按≤150m設(shè)計(jì)；單個(gè)系統(tǒng)的出力一般40t/h的（粉煤灰）。因?yàn)樨?fù)壓氣力輸送設(shè)備選擇了較高的管內(nèi)流速，且管道又不太長(zhǎng)，故管道通常選用耐磨合金材料。通常一個(gè)負(fù)壓輸送設(shè)備用一根輸送管，每個(gè)電場(chǎng)的灰斗構(gòu)成一條支線，經(jīng)過(guò)的切換閥門(mén)與主管相連。切換閥門(mén)通常選用專(zhuān)用的阻隔滑閥。

The negative pressure pneumatic conveying system has low investment and can be used for multi-point feeding and discharging. It requires a small clearance at the bottom of the hopper and is suitable for the ash removal system of 300MW and below thermal power units. Moreover, due to the fact that equipment and pipelines can only leak internally under vacuum, the environment is relatively clean. The disadvantage is that due to the limited negative pressure value, the conveying distance is relatively short. Generally, the geometric distance for conveying is 200m, and in actual engineering, it is recommended to design it as ≤ 150m; The output of a single system is generally 40t/h (fly ash). Because the negative pressure pneumatic conveying equipment chooses a higher flow rate inside the pipeline and the pipeline is not too long, wear-resistant alloy materials are usually used for the pipeline. Usually, a negative pressure conveying equipment uses a conveying pipe, and the ash hopper of each electric field forms a branch line, which is connected to the main pipe through a switching valve. Switching valves usually uses specialized blocking slide valves.

　　負(fù)壓設(shè)備的受料設(shè)備為料庫(kù)或中轉(zhuǎn)站。庫(kù)頂裝有灰氣別離設(shè)備、料位計(jì)和維護(hù)料庫(kù)不受過(guò)高背壓功真空破壞的真空壓力開(kāi)釋閥;庫(kù)內(nèi)設(shè)有氣化斜槽，以使庫(kù)內(nèi)物料能順暢卸出;庫(kù)底通常按工程需要設(shè)有不一樣方式的卸料設(shè)備?；?guī)鞖饣L(fēng)機(jī)、加熱器及卸料操控設(shè)備一般也安置在庫(kù)底。

The receiving equipment for negative pressure equipment is the material warehouse or transfer station. The top of the warehouse is equipped with ash separation equipment, level gauges, and a vacuum pressure release valve to maintain the material warehouse from high back pressure and vacuum damage; There is a gasification chute inside the warehouse to ensure smooth discharge of materials; The bottom of the warehouse is usually equipped with unloading equipment in different ways according to engineering needs. The gasification fan, heater, and unloading control equipment for the ash silo are generally installed at the bottom of the silo.

　　負(fù)壓氣力輸送設(shè)備所用的除塵設(shè)備，通常由旋風(fēng)除塵器和布袋除塵器構(gòu)成。旋風(fēng)除塵器選用雙門(mén)室構(gòu)造，布袋除塵器底部用負(fù)壓鎖氣閥與灰?guī)煦暯?，以阻隔管道?fù)壓與庫(kù)內(nèi)常壓，確保輸送和灰?guī)斓陌踩?。旋風(fēng)除塵器作為一級(jí)別離設(shè)備，除塵器功率>70%，二級(jí)布袋除塵器的功率在>99%以上，這二個(gè)設(shè)備均按壓力容器制作。經(jīng)二級(jí)除塵后的潔凈空氣經(jīng)過(guò)負(fù)壓風(fēng)機(jī)排入大氣。此外，灰?guī)焐线€另設(shè)有排氣布袋除塵器，用于處理庫(kù)內(nèi)氣化空氣等含塵氣體處理后的潔凈空氣直接排入大氣。依據(jù)粉煤灰的物理、化學(xué)特性，布袋除塵器均宜選用脈沖反吹式，反吹空氣的露點(diǎn)溫度宜為-23到-40℃。

The dust removal equipment used in negative pressure pneumatic conveying equipment usually consists of cyclone dust collectors and bag dust collectors. The cyclone dust collector adopts a double door chamber structure, and the bottom of the bag dust collector is connected to the ash storage by a negative pressure lock valve to block the negative pressure of the pipeline and the normal pressure inside the storage, ensuring the safety of transportation and ash storage. As a primary separation equipment, the cyclone dust collector has a power of over 70%, and the power of the secondary bag dust collector is over 99%. Both devices are made of pressure vessels. The clean air after secondary dust removal is discharged into the atmosphere through a negative pressure fan. In addition, there is also an exhaust bag filter installed on the ash silo, which is used to treat clean air containing dust such as gasification air in the silo and directly discharge it into the atmosphere. Based on the physical and chemical properties of fly ash, pulse back blowing is recommended for bag filters, and the dew point temperature of the back blowing air should be between -23 to -40 ℃.

　　負(fù)壓氣力輸送設(shè)備的氣源由擔(dān)任壓風(fēng)機(jī)或真空供給，通常請(qǐng)求擔(dān)任壓在-0.6Mpa以下，因?yàn)榻?jīng)過(guò)風(fēng)機(jī)的氣流中難免有一定量的塵料，因而請(qǐng)求負(fù)壓風(fēng)機(jī)過(guò)流轉(zhuǎn)道上的零件應(yīng)耐磨蝕，密封件防塵效果杰出。負(fù)壓風(fēng)機(jī)通常安置在灰為庫(kù)鄰近。

The air source of the negative pressure pneumatic conveying equipment is supplied by a pressure fan or vacuum, usually requiring a pressure below -0.6Mpa, because there is inevitably a certain amount of dust in the airflow passing through the fan. Therefore, it is requested that the parts on the flow passage of the negative pressure fan should be wear-resistant, and the sealing element should have excellent dust prevention effect. Negative pressure fans are usually installed near the ash storage area.

　　負(fù)壓氣力輸送設(shè)備的操控通常選用PLC程控，可選用模似或CRT顯現(xiàn)，上位機(jī)進(jìn)行數(shù)據(jù)處理，全主動(dòng)運(yùn)轉(zhuǎn)，信號(hào)的輸出、處理、聯(lián)網(wǎng)均很便利。

The control of negative pressure pneumatic conveying equipment is usually controlled by PLC program, which can be displayed in analog or CRT mode. The upper computer performs data processing and operates actively. The output, processing, and networking of signals are very convenient.

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