Anti-surge method for RTO combustion fan

Abstract

The invention discloses an anti-surge method for an RTO combustion fan, and belongs to the field of metallurgical automation. The method is applied to a three-chamber structure RTO system provided with six main burners. In order to solve the problems that a combustion fan is prone to surging after burners of an existing RTO system are all extinguished and energy loss exists in an existing solution, the anti-surging method achieves anti-surging through combination of hardware improvement and software optimization. In hardware, an anti-surge regulating valve is additionally arranged at an outlet of a combustion fan with the power of 18.5 KW, the pressure of 6.9 kPa, the flow of 4650 m / h and the air speed of 10.2 m / s, and combustion-supporting air is discharged through the near end to stabilize airflow; in software, PID control logic is optimized based on the proportional relation between the input number of the burners and the demand quantity of combustion air, and the opening degree of the adjusting valve is dynamically adjusted. According to the method, fan surge is eradicated, cold air is prevented from entering the RTO system, energy conservation is guaranteed, the system temperature is guaranteed to reach the standard, VOC treatment efficiency is guaranteed, implementation is easy, cost is controllable, and the method has wide popularization value.

Description

Technical Field

[0001] This invention relates to the field of metallurgical automation, and in particular to a method for preventing surge in an RTO (Regenerative Thermal Oxidizer) combustion fan. Background Technology

[0002] The core principle of a Regenerative Thermal Oxidizer (RTO) is to heat organic waste gas to above 760 degrees Celsius, causing the VOCs in the waste gas to oxidize and decompose into carbon dioxide and water. The high-temperature gas produced by oxidation is stored in a ceramic heat exchanger and used to preheat the subsequent organic waste gas, thereby saving fuel consumption. The ceramic heat exchanger in an RTO system needs to be divided into two or more zones or chambers, which sequentially undergo a heat storage-heat release-cleaning process. Only after cleaning is completed can the next heat storage process begin, ensuring a VOC removal rate of over 95%. If the organic matter contains elements such as halogens, and the oxidation products also include hydrogen halides, the purified gas is cooled by another heat exchanger before being discharged in compliance with standards. The different heat exchangers achieve the conversion between heat absorption and release through switching valves or rotating devices.

[0003] Most existing RTO systems are three-chamber structures equipped with six main burners, using independent temperature control for each chamber. In the color coating unit's RTO system, all burners are engaged during the oven baking stage. When the temperature is maintained at 850 degrees Celsius, the burners shut off sequentially according to a logical sequence, the natural gas double-shutdown valve closes, and the air throttling valve is closed to 0%. After normal production begins, the recovery solvent from the paint enters the RTO, the heat storage medium takes effect, and the system temperature can be maintained above 900 degrees Celsius without the need for natural gas-assisted heating. When the unit switches specifications or adjustments cause the temperature to drop below 850 degrees Celsius, the burners are engaged sequentially according to the control logic. During this process, the combustion fan needs to remain running to ensure rapid ignition and heating. However, when the burners do not require combustion assistance, the air throttling valves of all six burners are closed, causing the combustion fan to surge.

[0004] To address this issue, existing technologies modify the control logic to maintain a small opening in the burner throttle valve to alleviate surge. However, this approach results in cold air being directly introduced into the top of the RTO, severely impacting the system's energy-saving performance and presenting a significant drawback. Summary of the Invention

[0005] Purpose of the invention: To address the problem of surge in the combustion fan of existing RTO systems after all burners have automatically shut off, and the energy loss associated with existing solutions, this invention provides a method for preventing surge in RTO combustion fans, which eliminates surge while ensuring energy saving and improving the control of the RTO system.

[0006] Technical Solution: To solve the above-mentioned technical problems, according to one aspect of the present invention, more specifically, a method for preventing surge in an RTO combustion-supporting fan, including hardware improvements and software control optimization, as detailed below:

[0007] Hardware design: An anti-surge regulating valve is added at the outlet of the RTO combustion fan. This valve stabilizes the airflow of the fan by discharging combustion air near the burner when some or all burners in the RTO system are not in use. When the burners stop working and the air throttle valve is closed, the anti-surge regulating valve is slightly opened to prevent the combustion fan from surging due to poor airflow, and also prevents cold air from being discharged into the RTO system, thus ensuring the system's energy-saving effect.

[0008] Software control optimization: Based on the combustion control logic of the six main burners in the RTO system, the demand for combustion air is directly proportional to the number of burners in operation. Therefore, the control logic for the anti-surge valve was conceived and designed. By presetting the optimal opening position parameters of the anti-surge regulating valve corresponding to different burner operation numbers, the valve opening is dynamically adjusted according to the number of burners in operation. This ensures stable operation of the combustion fan when some burners are in operation, all are in operation, or all are stopped, while simultaneously meeting the combustion and temperature requirements of the RTO system.

[0009] Beneficial effects:

[0010] This invention solves the problem of fan surge caused by the original design flaws and improves the control and interlocking control of the RTO system. By using near-end exhaust of combustion air, cold air is prevented from entering the RTO system, ensuring the energy-saving effect of the system. The control logic and the number of burners are precisely matched to ensure that the RTO system temperature is stable and meets the standard without affecting the VOC treatment efficiency. The method is simple to implement, cost-controllable, and has broad application and promotion value. Attached Figure Description

[0011] Figure 1 This is a schematic diagram showing the installation position of the anti-surge regulating valve for the RTO combustion fan of the present invention;

[0012] Figure 2 This is a schematic diagram of the PID control logic for the anti-surge regulating valve of the RTO combustion fan of the present invention. Detailed Implementation

[0013] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Example 1

[0015] Reference Figures 1-2 A method for preventing surge in an RTO combustion fan is described. This method is applied to the RTO system of the Zhanjiang Iron and Steel cold rolling D109 unit. The specific implementation process is as follows:

[0016] Hardware Installation: Install an anti-surge regulating valve at the outlet of the RTO combustion fan (18.5KW power, 6.9kPa pressure, 4650m³ / h flow rate, 10.2m / s) of this unit. The installation position must strictly comply with... Figure 1 The layout shown ensures a sealed connection between the regulating valve and the fan outlet pipe, with the vent channel facing an undisturbed area to meet the pressure requirements for airflow discharge.

[0017] Software debugging: Based on the combustion control logic of the unit's six main burners, combined with... Figure 2 The PID control logic shown sets the anti-surge regulating valve opening parameters corresponding to different burner engagement numbers: when all 6 burners are engaged, the regulating valve is closed; when 3 burners are engaged, the valve is closed. Figure 2 The control logic operation shown sets the regulating valve opening to 30%; when all burners stop working, the control logic presets the regulating valve to maintain a slight opening of 15%. During the debugging process, through... Figure 2 The signal feedback mechanism shown monitors the opening degree of the regulating valve and the operating status of the fan in real time, ensuring that the burner's operation status and the opening degree of the regulating valve are linked in real time.

[0018] Implementation Results: After the method was implemented in 2022, the surge problem of the combustion fan in the RTO system of Zhanjiang Iron and Steel's D109 cold rolling mill was completely resolved. During normal production and when all burners were shut down, the fan operated stably. Furthermore, due to the adoption of… Figure 1 The near-end emission structure shown does not discharge cold air into the RTO system, so the system's energy-saving effect is not affected. The RTO system temperature is always maintained above 900 degrees Celsius, and the VOC removal rate remains above 95%, fully meeting production and environmental protection requirements.

[0019] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for preventing surge in an RTO combustion-assisted wind turbine, comprising hardware improvements and software control optimization, characterized in that, The specific steps for application in a three-chamber RTO system equipped with six main burners are as follows: Hardware improvements: An anti-surge regulating valve is added to the outlet side of the RTO combustion fan with a power of 18.5KW, a pressure of 6.9kPa, a flow rate of 4650m³ / h, and a wind speed of 10.2m / s. The regulating valve is used for near-end exhaust of combustion air. Software control optimization: Based on the combustion control logic of the 6 main burners in the RTO system, the combustion air demand is matched according to the actual number of burners in operation, and the optimal opening position of the anti-surge regulating valve is set; when some or all burners stop burning, the anti-surge regulating valve is slightly opened to prevent the combustion fan from surging and to prevent cold air from being discharged into the RTO system.

2. The method for preventing surge in an RTO combustion fan according to claim 1, characterized in that: The opening degree of the anti-surge regulating valve is proportional to the number of burners put in, and is dynamically adjusted as the number of burners put in changes.

3. The method for preventing surge in an RTO combustion fan according to claim 1, characterized in that: When all burners stop working, the anti-surge regulating valve maintains a preset slight opening to ensure stable airflow from the combustion fan.

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