负压气力输送设备的构成以及如何使用

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

　　负压气力输送设备通常由物料输送阀、进气止回阀、输送管道及阀门、灰气别离设备、贮灰库及辅佐设备、负压风机和操控设备等构成。物料输送阀又称E形阀，作为受料器的输送阀是负压设备的关键设备之一，其作用是经过物料输送阀上的补气阀和灰量调理设备的作业，使灰斗内的灰与空气均匀混合，灰气混合物具有杰出的流动性，可使其顺畅进入输送管道，以确保输送设备、晓畅地运转。物料输送选用气支操控，其阀体和阀具有杰出的耐磨性。

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.

　　进气止回阀选用旋启式构造，当输送管道内浓度过高造成输送支管进气端真空值过高时，进气止回阀主动打开，补人适当的空气以稀释过高的物料浓度，以避免堵管的发作。

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.

　　负压气力输送系统指利用压风机（真空泵）产生系统负压，将在受料器处与空气均匀混合的粉粒状物料通过管道抽送贮料装置的输送系统，主要用于燃煤电厂的灰处理系统，又称负压气力除灰系统，为国外引进技术，其系统设计技术已为国内除灰系统设计人员完全掌握。

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.

　　负压气力输送系统投资少，可以进行多点上料、下料，要求料斗下部的净空较小，适用于300MW及以下火电机组的除灰系统，且由于设备和管路在真空状态下只能发生内泄漏，因而环境比较清洁。缺点是由于负压值有限，因而输送距离较短，一般输送的几何距离为200m，实际工程宜按≤150m设计；单个系统的出力一般40t/h的（粉煤灰）。因为负压气力输送设备选择了较高的管内流速，且管道又不太长，故管道通常选用耐磨合金材料。通常一个负压输送设备用一根输送管，每个电场的灰斗构成一条支线，经过的切换阀门与主管相连。切换阀门通常选用专用的阻隔滑阀。

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.

　　负压设备的受料设备为料库或中转站。库顶装有灰气别离设备、料位计和维护料库不受过高背压功真空破坏的真空压力开释阀;库内设有气化斜槽，以使库内物料能顺畅卸出;库底通常按工程需要设有不一样方式的卸料设备。灰库气化风机、加热器及卸料操控设备一般也安置在库底。

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.

　　负压气力输送设备所用的除尘设备，通常由旋风除尘器和布袋除尘器构成。旋风除尘器选用双门室构造，布袋除尘器底部用负压锁气阀与灰库衔接，以阻隔管道负压与库内常压，确保输送和灰库的。旋风除尘器作为一级别离设备，除尘器功率>70%，二级布袋除尘器的功率在>99%以上，这二个设备均按压力容器制作。经二级除尘后的洁净空气经过负压风机排入大气。此外，灰库上还另设有排气布袋除尘器，用于处理库内气化空气等含尘气体处理后的洁净空气直接排入大气。依据粉煤灰的物理、化学特性，布袋除尘器均宜选用脉冲反吹式，反吹空气的露点温度宜为-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 ℃.

　　负压气力输送设备的气源由担任压风机或真空供给，通常请求担任压在-0.6Mpa以下，因为经过风机的气流中难免有一定量的尘料，因而请求负压风机过流转道上的零件应耐磨蚀，密封件防尘效果杰出。负压风机通常安置在灰为库邻近。

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.

　　负压气力输送设备的操控通常选用PLC程控，可选用模似或CRT显现，上位机进行数据处理，全主动运转，信号的输出、处理、联网均很便利。

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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