This article describes the thermal power plant ash transmission system workflow and control requirements, storage pump positive pressure pneumatic conveying technology has begun to use at home to further promote the domestic power plant fly ash pneumatic conveying technology. Pneumatic conveying system, transmission distance, transmission levels, the system output and equipment and automation level of manufacturing process to be strengthened and enhanced. Ash for the position control of the pump s use of OMRON C200H PLC, in Thermal Power Plant Ash control system, realized the warehouse may feed pump, intake, exhaust, and so the process of discharging computer control. This paper gives a specific implementation plan, constituted by the device control system operating normally, its overall efficiency is very obvious.
Boiler ash handling system consists of two three-field filter, electric air lock device 12, two feed machines, two skewed fan, four storage pumps, three air compressor, a gray component library and connecting pipe .
Thermal Power Plant Ash flow: ESP hopper air lock device ???? ???? ???? chute feed machine ???? ???? Pumps ???? Ash Ash, from the dust collector hopper to Ash Ash some specific procedures: the first in the warehouse Pump body stress-free situation, the feed valve and open the release valve (with conductive dust collector hopper sump pumps to ensure that sump pumps air emissions), start the air lock device, the power struggle within the Ash and dust ash materials by air lock device chute feed machine ???? ???? feed pump valve into the warehouse, when the pump reaches the gray materialTo a certain extent, stop the operation of air lock device, closing the feed, gas discharge valve device 2, open the valve, and then entered the air valve, use compressed air to pump material through the gray to gray Ash pipe tower. Then for material deflation, a cycle, complete the ESP isolated gray ash sent to the task of Kuta. Throughout the production process of the system has an important role in normal operation to ensure coal-fired boiler burning Ash generated from the transmission time out.
Pumps Ash in the control process a large number of chain and lock. Such as: ???? in the warehouse are still left with the weight of the pump case can only be moved into an open valve relief valve is prohibited, both feed and discharge gas valve not fully closed to prohibit the open into the air valve to prevent return to Ash ; ???? Pressure in the gray value than to allow high outlet valve is opened and closed into the air valve to prevent gray pipe blockage or blockage of failure become larger; ???? Pipe Pressure in the lower air lock opens into the air valve to prevent plugging tube; ???? into the air valve not completely closed in, the closed valve and a large open feed valve; ????è When the storage pump gray material has reached the predetermined position and height, the ipsilateral Pumps another state and not a material Pipe Pressure air has reached the specified value, the chain opened a meter into the air valve to the feed material; when the air pressure drops below the specified value the mother tube, the chain closed inlet, outlet valve, stop the discharge; also those who have valve fault detection system, when a valve from the fully closed position to the fully open position or from the fully open position to the fully closed position of the movement for more than a certain time value, then the issue of acoustic alarm signals to alert operating personnel, the valve has been card should be processed immediately.
Ash 1 warehouse control system pump working principle
Ash handling system is to use compressed air to dry ash along the pipeline to Ash Ash or interim storage, transport of air pressure is high, a longer transmission distance. Feed valve from the cone valve, connecting rod and piston switch components, when the piston is pressure pushing the piston missing first department, the link led to cone valve rocker lever down, open the feed valve; the other hand, when the piston switch When the piston is in the lower part, by the spring piston pressure switch to push to the top of the cone valve and with the rubber ring compression, then the feed valve is turned off.
intake valve is a valve on the upper and lower air pressure difference and the role of the spring to maintain a certain balance between the opening to lack a certain amount of compressed air into the body, so lack of material gasification body through the pressure cylinder and pipeline poor, the gasification of the material sent to the pipeline.
Pumps work, press the start button, the system put into operation, the exhaust valve opens, by the time delay relay: delay time that the inlet valve is open, feeding time is measured by what a time relay material over time: at least delay the time to feed, to close the release valve and feed valve. At this point the production process should be transferred to the next, when the storage pump pressure to achieve a given value, sump pumps should be out on the material production process. At this point the intake valve and the outlet valve is opened, the expected delay time delay relay began, the expected completion, and the expected delay time to, shut valve and outlet valve, automatically switch to the production of feed process, open valve, and then entered the valve, so the cycle of production. </ P>
2 power plant ash handling system at present the situation Pumps
Units of a thermal power plant system of Ash Kong Zhi and equipment due to design different aspects, levels of some problems, causing the system are put into operation since, operating conditions has been less satisfactory, mainly of the following problems.
2.1 Pumps without level meter
the original configuration of the system level meter (capacitance level meter) less reliable, can not accurately measure the material level positions within the pump, so when debugging is to replace the relay on the level gauge, so that operating personnel do not well aware of the situation of the current position within the pump case of gray feeding amount, simple to operate according to the time, so because of operational errors, out of control, which frequently causes the system blockage, leakage problems affecting the production.
2.2 Control System Design unreasonable Pumps
Original design of control systems and Shi Jian by intermediate relay relay Gou Cheng, and Ji relay control system, which in the run O clock Suo shown Tuchuwenti is: relay often Yin more dust in the surrounding environment and poor contact , and thus the entire system does not work, followed by control cabinet, console connections within and between cables, wires is very large, also caused the equipment failure rate, maintenance of large amount of maintenance cost.
2.3 ESP ash bucket unreasonable Level Design Selection
Not conducive to energy saving, The original ESP ash bucket device equipment level meter for the Locked-type level meter and monitor use only, and basically not functioning, can not provide effective signals, which result in post-operators in ignorance of the situation (Level ash bucket real situation), can only seat of your pants, rule of thumb operation, so there has been almost no ash bucket material, and the operators are starting devices out of materials and hence the gas device, feed machine and sump pumps end efficiency of equipment operation, equipment and energy cause great waste.
In order to overcome these defects, guarantee system security and stability of operation, environmental protection and energy saving and other considerations, the unit made technical reformation Goucheng by the PLC controlling system, Dian Dong air lock device. Electric lock device is a universal feeding device, usually installed with the boiler precipitator ash hopper and material sent between devices, as the pneumatic ash handling system of the pre-feeding equipment, or installed in storage or transit Ash Ash Unloading gray Department, as a follow-up transportation equipment feeding equipment.
3 positions after the transformation of the functional requirements of the pump
After transformation, should give the system a manual operation mode and automatic operation mode, manually run the function is based on the system status to the appropriate person to operate the equipment.
3.1 Manual Operation
3.3.1 Close the A (B) side of the pump control power switch positions.
3.1.2 will be a (b) hand side of sump pumps / automatic to manual operation mode selector switch position.
3.1.3 will be a (b) ESP hopper air lock device, manual / automatic to manual operation mode selector switch position.
3.1.4 Open the corresponding positions in the pump began to feed into the valve, exhaust lights.
3.1.5 under the ESP hopper feed of places to start hopper air lock device operation (Note: When the time required to start the last one lock gas reactor start up process, the warehouse began to pump the feed delay time ; after delay in this process the feed gas may not start and stop locking device, or they will re-start time, full tank failure prone).
3.1.6 expected full indicator light or feeding time (depending on the device operation is tentatively scheduled for: single lock gas runs, feeding time for 7 minutes; two lock gas runs, feeding time was 3 minutes; more than three and the number of lock gas station runs, feeding time is 1.5 minutes) that will run the air lock stops running (Note: the feed delay from the last one air lock starts after the completion time).
3.1.7 air lock stops running, the required interval of 5 seconds, then close the inlet valve and discharge valve.
3.1.8 feed valve and release valve closed, requires at least 10 seconds after the interval to the material.
3.1.9 satisfy the requirements in air pressure (???? 0.55MPA) cases, open into the air valve to discharge, into the wind indicator light, full of light materials destroyed.
3.1.10 When the airPressure dropped to the specified value (0.12MPA), the completion of the material, close into the air valve, into the air valve closed for at least 15 seconds before opening the feed valve. Since then entered the next cycle.
3.2 Automatic Operation
The function automatically: the plant s dust, B side of the set of positions Ash pump automatic control system, a side of the automatic conveying system also controls 1, No. sump pumps run automatically, B-side automatic conveying system at the same time Control 3, No. sump pumps run automatically, only the A (B) side of the two positions can pump storage under the normal operation of the pump to get ready for automatic operation. Automatic run-time system preference number (or numbers) into the storage pump, discharge, and then number (or numbers) sump pumps out of material, and so alternately repeated, when the air lock device automatically hopper into the low gray bits, the gray position lamps also light, the system can automatically start the corresponding hopper air lock runs, and keep to the low ash bucket dropped to less material was banned from the start, when the dust hopper up to the gray bit more than the median, the ash bucket down and remembered, and to prepare for control of air lock Used. Dang warehouse full feed pump or feed time to automatically stop running the air lock, close sump pumps into the valve, open the sump pumps to allow feeding time for 7 minutes (in the debugger, the time to do appropriate modifications to meet production requirements). When there are two options to meet the ash bucket, sump pumps to allow the feed for 3 minutes (the time in debugging can be modified to meet production requirements). When 3 or more units to meet the selection criteria ash bucket, the sump pumps to allow the feed time of 1.5 minutes (Re-commissioning, the time to do appropriate modifications to meet the requirements of the production) automatic conveying system start time, the ash bucket, if other conditions are met Ash, the ash hopper air lock does not automatically start, only to the next a cycle was chosen to participate in Ash.
After the dual transformation of the system s main function is to store the pump through two alternating pump single warehouse loading and unloading the material in a continuous transmission, dual position pump control system includes instructions institutions Pumps, compressed air control piping, etc., by the them to control the implementation of warehouse materials and feed pump installation, pump alternation of two single-position discharge control discharge valve has two inlet and a discharge port, through the switching valve to pump out two single-store materials alternating with a gray pipe tube connect. When a material is in the state, another state in the feed.
Two-position control system, including pump warehouse full instructions institutions, such as compressed air control piping. By their position to control the implementation of the feed pump installation materials. Two alternating single warehouse pump discharge valve. Outlet valve has two inlet and a discharge port, through the switching valve to pump out two single-warehouse on the gray pipe material alternately connected. Power Plant Ash Flow Chart 1
3.3 Transformation Programme
According to the existing problems and to achieve the function, combined with the existing technical capacity of the plant technical staff through discussion and demonstration of the following rehabilitation programs.
Core of the problem --- part of control system with OMRON Corporation C200H Series Programmable Logic Controller PLC to replace the middle (A pair sent to the monitor outside the system (material level indicator), as the run operator to monitor material level with the dust hopper.
on sump pumps, feed machine, air lock device and ESP ash bucket and other equipment or material level parameters of the connection between the (closed) locking systems to modify, improve, is the sump pumps do not work a short time (Ash), the , feed machine, air lock device and other equipment is not running, when the electrostatic precipitator hopper falls below a predetermined material level within the position is not for ash handling system operating to ensure that the system is always running in high efficiency, reduce or eliminate unnecessary equipment consumption, which can reach the purpose of energy saving.
All in all, this transformation is to use programmable logic controllers (PLC) control system as the core component, the external use of dust hopper level gauge, level gauge pump storage, and related equipment (sump pumps, feed machine , air lock, etc.) of the running mother of pipe blowing air pressure as the output signal; output control sump pumps in / out air locking device, feed machine and air compressor equipment or load parameters.
Figure 1 power plant ash handling flow chart
4 PLC input and output of the point distribution
under the control of the request, the selected input relay number is: 00400 ~ ~ 00611,00700 00511,00600 00411,00500 ~ ~ 00 714, is the PLC to accept external input relay switch signal input device interface, so these ports and buttons, reflecting the state of the signal device is connected; output relay number is 01200 ~ 01206,01300 01309,01400 ~ ~ ~ 01607,01700 01507,01600 01409,01500 ~ ~ 01707, the output relay is the PLC input terminal send signals to the external load interface, so these ports are used to control light, electromagnetic valve. Specific I / O distribution shown in Table 1.
5 debug control system operation results
Technological transformation through the PLC, the equipment level of automation and efficiency has been improved. Through a long run situation, the normal equipment operation, maintenance, repair workload reduced, greatly reducing maintenance and overhaul costs; can accurately measure the material level positions in the pump is operating personnel can accurately grasp the position of running the pump; on ESP ash bucket can also be under the effective operation of the signal and improve air lock device, feeding Conveyors and storage pumps and other equipment operating efficiency and reduce wear and tear of equipment and energy waste; ensure the normal operation of the system according to process requirements to achieve the desired purpose. Table 1 programmable controller input and output points allocation table
pse "cellSpacing = 0 cellPadding = 0 width = 581 border = 1> NT-FAMILY: Arial "> type" point output point Output point DING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 1pt solid; WIDTH: 141.55pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid "vAlign = top width = 189> 1 ~ 12, low ash bucket Level: IGHT:-18.05pt "> 00400 ~ 00411 T:-21pt "> A, B-side automatic instructions: 01200 ~ 01201 : Windowtext 1pt solid "vAlign = top width = 203> 3 sump pumps discharging control (mean Show): 01,403 LETTER-SPACING: 1.2pt "> ~ 01404 1 .2 Pt "> No. ~ 12, median ash bucket position: 00500 ~ 00511 T: medium none; WIDTH: 141.55pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid "vAlign = top width = 189> 1 ~ 4, gray pipe blocking alarm: pt "> 0120 2 ~ 01205 lang = EN-US style = "LETTER-SPACING: 1.2pt"> 4 ???¤Pumps feed control (indicated): 01405 ~ 01406 -TOP: medium none; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: windowtext 1pt solid; WIDTH: 141.55pt; PADDING-TOP: 0cm; BORDER-BOTTOM: windowtext 1pt solid "vAlign = top width = 189> 1 ~ 12, air lock runs:
The C200H PLC to control the composition of the ash conveying system security, stability, easy operation, control flexibility, less maintenance, change control system is pretty easy, and there can meet the production requirements, so the value of this system is to promote .