A method for constructing a boiler gas blending system

Abstract

The invention relates to the technical field of system interlocking control, and specifically discloses a method for constructing a boiler coal gas blending system, comprising the following steps: 1) the hardware part of the boiler coal gas blending system is connected to a DCS system A and a DCS system B through a group of signal transmission cables; 2) the DCS system A collects the operation data of the boiler body, executes a "boiler operation abnormality" safety interlocking judgment program for these data, and transmits the result to the DCS system B via a DO relay and a signal transmission cable; 3) the DCS system B collects the production operation data of the coal gas blending system and the "boiler operation abnormality" switch quantity signal transmitted by the DCS system A, and performs logical judgment and processing on these data; 4) finally the DCS system B remotely controls the start and stop of field equipment and the frequency conversion of a booster fan and the adjustment of a valve opening; the invention reasonably utilizes the system hardware resources, does not have the transmission problems such as data packet loss and optical signal attenuation, and achieves the purpose of reducing costs and increasing efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of system interlocking control, and in particular to a method for constructing a boiler gas blending system. Background Art

[0002] During the coke production process, 60,000 m3 of 3 The coal gas cannot be consumed and is forced to be released. These coal gases contain a large amount of harmful substances such as sulfides, which not only pollute the environment but also waste energy. In order to achieve both economic and social benefits, the company decided to carry out coal gas blending technology transformation on two 75T fluidized bed boilers. In order to ensure the safety of the coal gas blending system, 14 important operating data such as boiler primary fan / secondary fan / induced draft fan, boiler total air volume, boiler drum water level, furnace outlet pressure, oxygen content, etc. must be introduced into the coal gas blending system as safety interlock conditions. These data only exist in the original Honeywell C200DCS system. The newly purchased coal gas blending control system is the Hollysys K series DCS system. How to integrate the data scattered in the Honeywell C200DCS system and the Hollysys K series DCS system to build a complete boiler coal gas blending system has become a difficult and key point in the transformation. Therefore, it is necessary to design a method to build a boiler coal gas blending system based on the Hollysys and Honeywell dual DCS systems to solve the problem of no communication between DCS systems and inability to safely control. Summary of the invention

[0003] In view of the problems existing in the prior art, the object of the present invention is to provide a method for constructing a boiler gas blending system.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a method for constructing a boiler gas blending system, comprising the following steps:

[0005] 1) The hardware part of the boiler gas blending system is connected to DCS system A and DCS system B through a set of signal transmission cables;

[0006] 2) DCS system A collects the operation data of the boiler body through AI cards and DI cards, and then uses the control processor of DCS system A to execute the "boiler operation abnormality" safety interlock judgment program on these data, and finally obtains the switch value result of whether the boiler operation is abnormal. The result is transmitted to DCS system B via DO relay and signal transmission cable;

[0007] 3) DCS system B collects the production and operation data of the gas blending system and the "boiler operation abnormality" switch signal transmitted by DCS system A through AI cards and DI cards, and then uses the control processor of DCS system B to perform logical judgment and processing on these data;

[0008] 4) Finally, the AO card and DO card of DCS system B remotely control the start and stop of the on-site equipment and the frequency conversion of the booster fan and the adjustment of the valve opening.

[0009] Specifically, the DCS system A in step 1) is a Honeywell C200 DCS system, and the DCS system B is a Hollysys K series DCS system.

[0010] Specifically, the operating data of the boiler body in the step 2) performs safety interlock logic operations in the DCS system A. When any of the following conditions is met in the operating data: the primary fan stops, the secondary fan stops, the induced draft fan stops, the total air volume of the boiler is less than 30%, the water levels of the two boiler drums are simultaneously above the upper limit or below the lower limit, the pressures of the two furnace outlets are simultaneously greater than -0.5 kPa, the oxygen content is less than 3%, the gas pressure before the booster fan is less than 1.5 kPa, and the boiler body MFT trips, a "boiler operation abnormality" signal is sent to the DCS system B.

[0011] Specifically, the functions of the software system of the DCS system B in the step 3) include the monitoring operation of the on-site equipment of the gas blending system, the fire extinguishing protection of the gas blending system, the MFT (main fuel trip) safety interlock of the gas blending system, and the latching and resetting of the primary cause of the gas blending system trip.

[0012] Specifically, the MFT safety interlock of the gas blending system collects the "boiler operation abnormality" signal transmitted by the DCS system A and the local emergency stop button of the gas blending system, the DCS emergency stop button, the abnormal combustion air pressure, the abnormal gas pressure, the loss of burner flame, and the main gas valve closure signals in a unified manner, and sends them all to execute the safety interlock program segment of the system. When any of the interlocking conditions is triggered, a "gas blending MFT stop" signal is issued to stop the system on site.

[0013] The present invention has the following beneficial effects:

[0014] The invention discloses a method for constructing a boiler gas blending system.

[0015] 1. The hardware circuit constructed does not add any communication module equipment and any communication protocol. It directly connects the switch output channel and switch input channel of the two systems in a hard-wired manner. The advantage of this transmission method is that there is no transmission problem such as data packet loss and optical signal attenuation. It is currently the most reliable signal transmission method;

[0016] 2. Reasonable use of system hardware resources, placing the "abnormal boiler operation" safety interlock part in the Honeywell C200 DCS system, and placing the "gas blending MFT shutdown" safety interlock part in the Hollysys K series DCS system. This combination and innovation of programming technology alone can save up to 30,000 yuan in signal distributor procurement costs, 2,500 yuan in cable procurement costs, 28 system 24V power supplies, and installation space for 28 signal distributors in the control cabinet, compared with the traditional safety interlock system that is all arranged in the Hollysys K series DCS system;

[0017] 3. In terms of the selection of the gas blending system, we broke through the restriction of continuing to use the American Honeywell DCS system and switched to the more cost-effective domestic Hollysys K system DCS system, which not only met the needs of actual production and operation, but also saved 260,000 yuan in equipment procurement costs, and more effectively promoted the process of localization of the company's control system;

[0018] 4. In addition to the MFT parking safety interlock function, the gas blending system also has the function of latching and resetting the primary cause of the system shutdown; it helps to accurately locate the cause of the system shutdown at the first time, facilitates the targeted and rapid troubleshooting and treatment of fault problems, and realizes rapid resumption of production. At the same time, it also provides first-hand valuable information for accident analysis reports;

[0019] 5. After the boiler gas blending system was put into use, the boiler blended gas volume was about 60,000 cubic meters / day, saving about 37 tons of standard coal / day. It not only solved the environmental pollution problem and met the requirements of environmental protection indicators, but also avoided energy waste and achieved the goal of reducing costs and increasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the structural diagram of the boiler gas blending system.

[0021] Figure 2 This is the data flow chart of the boiler gas blending safety interlock system.

[0022] Figure 3 This is the software function diagram of the boiler gas blending system. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely further describe the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] like Figure 1-3As shown, a method for constructing a boiler coal-gas blending system is provided, which collects, calculates and transmits important parameters of the boiler body scattered in the Honeywell C200 DCS system and the coal-gas blending system monitoring data in the Hollysys K series DCS system, and constructs a complete boiler coal-gas blending system. The main functions of the system include three parts: First, the basic monitoring and operation function, including the control room display of the production operation status, as well as the remote single-point operation of the field equipment and the sequential control operation of nitrogen replacement, gas replacement, main gas gun program control, small gas gun program control, etc. Second, the fire extinguishing protection function of the gas blending system. When the fire detection fails to detect fire during the production operation, or when the fire detection fails to detect fire during the start-up ignition process, the burner vent valve will be automatically opened, the burner air intake valve will be closed, and the ignition valve will be closed, but it can be quickly re-ignited without causing the gas blending system MFT to stop; Third, the MFT safety interlock function that directly causes the gas blending system to stop. When the MFT is triggered to stop, the booster fan will be stopped, the main gas valve of the gas blending system will be closed, the main vent valve of the gas blending system will be opened, the burner air intake valve will be closed, the ignition valve will be closed, and the burner vent valve will be opened, and the gas blending system will stop. Fourth, the gas blending system tripping primary cause latching and reset function.

[0025] This system mainly consists of two parts: the boiler gas blending system hardware part and the boiler gas blending system software part.

[0026] 1.1 The hardware part of the boiler gas blending system is mainly composed of Honeywell C200 DCS system, Hollysys K series DCS system and a set of signal transmission cables.

[0027] 1.1.1 The main functions of Honeywell C200 DCS system are: using the AI ​​card and DI card of the system to collect important operating data of the boiler body, and then using the C200 control processor to execute the "boiler operation abnormality" safety interlock judgment program on these data, and finally obtain the switching value result of whether the boiler operation is abnormal. The result is transmitted to the Honeywell K series DCS system through the DO relay and the transmission cable between the two systems.

[0028] 1.1.2 The main functions of Hollysys K series DCS system are: using the AI ​​card and DI card of the system to collect the production and operation data of the gas blending system and the "boiler operation abnormality" switch signal transmitted by Honeywell C200DCS system, and then using the K-CU01 control processor to perform logical judgment and processing on these data, and finally through the AO and DO cards, to achieve remote control of the start and stop of the on-site equipment and the frequency conversion of the booster fan and the adjustment of the valve opening.

[0029] 1.2 The software part of the boiler gas blending system is mainly composed of Honeywell C200DCS system program segments and Hollysys K series DCS system program segments.

[0030] 1.2.1 The main function of the Honeywell C200DCS system program segment is to perform safety interlocking logic operations on 14 important operating data of the boiler body. When any of the following conditions are met: the primary fan stops, the secondary fan stops, the induced draft fan stops, the total air volume of the boiler is less than 30%, the water levels of the two boiler drums are simultaneously above the upper limit or below the lower limit, the pressures of the two furnace outlets are simultaneously greater than -0.5kPa, the oxygen content is less than 3%, the gas pressure before the booster fan is less than 1.5kPa, and the boiler body MFT trips, a "boiler operation abnormality" signal is sent to the Honeywell K series DCS system.

[0031] 1.2.2 The main functions of the Hollysys K series DCS system program segment are: monitoring and operation function of on-site equipment of the gas blending system; fire extinguishing protection function of the gas blending system; MFT safety interlock function of the gas blending system; and the first cause latching and resetting function of the gas blending system tripping.

[0032] The MFT safety interlock function of the gas blending system collects the "boiler operation abnormality" signal transmitted by the Honeywell C200DCS system and the local emergency stop button of the gas blending system, the DCS emergency stop button, the abnormal combustion air pressure, the abnormal gas pressure, the burner flame loss, and the main gas valve closure signal, and sends them all to execute the safety interlock program segment of the system. When any of the interlocking conditions is triggered, the "gas blending MFT stop" signal is issued to stop the system on site.

[0033] 1. Rationally design the system architecture of the coal-gas blending system to perfectly integrate the data scattered in the Honeywell C200 DCS system and the Hollysys K series DCS system to build a complete boiler coal-gas blending system.

[0034] 2. The communication loop is built in a hard-wired way, which solves the problem of no communication protocol (such as modbus communication, TCP / IP communication, 485 communication, etc.) and port between two different DCS systems.

[0035] 3. Reasonable use of system software and hardware resources, negating the traditional solution of using signal distributors to transmit data from Honeywell C200 DCS system to Hollysys K series DCS system, combined with the combination and innovation of programming technology.

[0036] 4. Optimized the control system selection plan, breaking through the limitation of continuing to use the American Honeywell DCS system, and adopted the domestically produced Hollysys K system DCS system, saving 260,000 yuan in equipment procurement costs.

[0037] 5. To program separately in two different control systems at home and abroad, our rectification team must not only be proficient in the ControlBuilder program configuration software and HMI drawing configuration software of the American Honeywell C200DCS system, but also be proficient in the programming and debugging of the engineering general control configuration software of the domestic Hollysys DCS system. At the same time, our rectification team must have rich experience in upgrading and transformation.

[0038] 6. In the process of building a hard-wired communication loop, the Honeywell C200DCS system side selects the DO channel with relay isolation. The system does not distribute power to the outside and is connected using a wet node wiring method on site. On the other end of the cable, the domestic Hollysys K series DCS system side selects the DI channel without relay isolation. The system provides external power distribution and a dry contact wiring method on site to ensure that different devices at both ends of the communication cable send and receive the same type of signals.

[0039] The present invention is not limited to the above-mentioned implementation modes, and anyone should be aware of the structural changes made under the enlightenment of the present invention, and all those having the same or similar technical solutions as the present invention fall within the protection scope of the present invention.

[0040] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A method for constructing a boiler gas blending system, characterized in that: The following steps are involved: 1) The hardware part of the boiler gas blending system is connected to DCS system A and DCS system B through a set of signal transmission cables; 2) DCS system A collects the operation data of the boiler body through AI cards and DI cards. The operation data of the boiler body performs safety interlock logic operations in DCS system A. When any of the following conditions are met in the operation data: the primary fan stops, the secondary fan stops, the induced draft fan stops, the total air volume of the boiler is less than 30%, the water levels of the two boiler drums are simultaneously over the upper limit or under the lower limit, the pressures of the two furnace outlets are simultaneously greater than -0.5kPa, the oxygen content is less than 3%, the gas pressure before the booster fan is less than 1.5kPa, and the boiler body MFT trips, a "boiler operation abnormality" signal is sent to DCS system B; the control processor of DCS system A then executes the "boiler operation abnormality" safety interlock judgment program on these data, and finally obtains the switch value result of whether the boiler operation is abnormal, which is transmitted to DCS system B via the DO relay and signal transmission cable; 3) DCS system B collects the production and operation data of the gas blending system and the "boiler operation abnormality" switch signal transmitted by DCS system A through AI cards and DI cards, and then uses the control processor of DCS system B to perform logical judgment and processing on these data; the functions of the software system of DCS system B include the monitoring operation of the on-site equipment of the gas blending system, the fire extinguishing protection of the gas blending system, the MFT safety interlock of the gas blending system, and the first cause latching and resetting of the gas blending system tripping; the MFT safety interlock of the gas blending system is to collect the "boiler operation abnormality" signal transmitted by DCS system A and the local emergency stop button of the gas blending system, the DCS emergency stop button, the abnormal combustion air pressure, the abnormal gas pressure, the loss of burner flame, and the closing of the main gas valve in a unified manner, and all of them are sent to execute the safety interlock program segment of the system. When any of the interlock conditions is triggered, the "gas blending MFT stop" signal is issued to stop the system on site; 4) Finally, the AO card and DO card of DCS system B remotely control the start and stop of the on-site equipment and the frequency conversion of the booster fan and the adjustment of the valve opening.

2. The method for constructing a boiler gas blending system according to claim 1, characterized in that: The DCS system A in step 1) is a Honeywell C200 DCS system, and the DCS system B is a Honeywell K series DCS system.

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