Steam regulating device and regulating method for thermal system

Abstract

The application discloses a kind of thermal system steam regulating device and adjusting method, belong to steam control technical field, including determining the outlet standard steam pressure of direct current steam generating device, standard steam superheat, standard feedwater regulating valve opening and standard feedwater flow;Determine the minimum superheat;In direct current steam generating device access equal steam pressure controller and equal safety margin controller;According to direct current steam generating device load and feedwater flow strain curve selects equal steam pressure controller or equal safety margin controller;According to the controller corresponding to selected acquisition feedwater regulating valve opening, adjusts feedwater regulating valve opening and adjusts thermal system steam output state.This application uses equal steam pressure controller and equal safety margin controller cooperative control, so that the safety controller and performance controller of direct current steam generating device can be designed separately, do not affect each other, eliminate the design constraint of safety to performance controller, so that thermal system steam regulating process is efficient and convenient.

Description

Technical Field

[0001] This invention belongs to the field of steam control technology, specifically relating to a steam regulating device and regulating method for a thermal system. Background Technology

[0002] The once-through steam generator is one of the main pieces of equipment in the thermal system of the heating industry. Its main function is to transfer external heat to the feedwater of the steam generator, turning it into steam at a certain temperature and pressure. Once-through steam generators have relatively small heat storage and water capacity, and respond quickly to power changes. The small heat storage and water capacity also make the outlet steam parameters more sensitive and fluctuate more significantly, which places more stringent requirements on the control system of the once-through steam generator.

[0003] When regulating the outlet steam pressure of a once-through steam generator, if the outlet steam pressure is lower than the control command value, the opening of the feedwater regulating valve is increased to increase the feedwater flow rate, thereby increasing the outlet steam flow rate and thus raising the pressure; conversely, the pressure is lowered. The external heating or heat exchange process of a once-through steam generator has significant thermal inertia. If the feedwater flow rate increases too rapidly during rapid load increases, the heating capacity of the steam generator will not match the heat exchange demand on the feedwater side. This results in insufficient heat for vaporization on the feedwater side, causing the outlet steam of the once-through steam generator to contain water droplets or even produce hot water, affecting the safe operation of the steam-using equipment. Summary of the Invention

[0004] In view of one or more of the above-mentioned defects or improvement needs of the prior art, the present invention provides a steam regulation method for a thermal system to solve the problem that the outlet steam of the existing direct current steam generator is prone to water droplets or even hot water.

[0005] To achieve the above objectives, the present invention provides a steam regulation method for a thermal system, comprising the following steps:

[0006] S1. Under normal operating conditions, the standard steam pressure at the outlet of the DC steam generator is p1, the standard steam superheat at the outlet of the DC steam generator is ΔT1, the standard feedwater regulating valve opening is k1, and the standard feedwater flow rate is m.

[0007] S2. For the steam superheat at the outlet of the DC steam generator, the minimum superheat is determined to be ΔTmin. When the steam superheat at the outlet of the DC steam generator is less than ΔTmin, the steam at the outlet of the DC steam generator carries water droplets or hot water.

[0008] S3. Connect an equal steam pressure controller C1 and an equal safety margin controller C2 to the DC steam generator. The equal steam pressure controller C1 adjusts the opening of the feedwater regulating valve according to the steam pressure p, and the equal safety margin controller C2 adjusts the opening of the feedwater regulating valve according to the steam superheat ΔT. The load-feedwater flow strain curve of the DC steam generator is an adjustment curve that allows the DC steam generator to be quickly adjusted to the set steam outlet rate without producing water droplets or hot water by adjusting the opening of the feedwater regulating valve.

[0009] S4. Select an equal steam pressure controller C1 or an equal safety margin controller C2 based on the load and feedwater flow strain curve of the DC steam generator to ensure that there are no water droplets or hot water at the outlet of the DC steam generator.

[0010] S5. Obtain the opening degree k of the feedwater regulating valve according to the corresponding selected controller, and adjust the opening degree of the feedwater regulating valve of the DC steam generator to regulate the steam output state of the thermal system.

[0011] As a further improvement of the present invention, in step S3, the equal safety margin controller C2 adjusts the opening of the water supply regulating valve according to the safety margin α.

[0012] As a further improvement of the present invention, the safety margin α is calculated as follows:

[0013] α = ΔT / ΔTmin (Formula 1).

[0014] As a further improvement of the present invention, the selection of the controller in step S4 includes:

[0015] Obtain the current steam pressure p2, calculate the ratio of the current steam pressure p2 to the standard steam pressure p1, and obtain the first output signal u1;

[0016] Obtain the safety margin α2 under the current state, calculate the safety margin α1 under the standard state, calculate the ratio of the safety margin α2 under the current state to the safety margin α1 under the standard state, and obtain the second output signal u2.

[0017] Compare the first output signal u1 and the second output signal u2, and use the controller with the smaller output signal as the final controller for regulating the DC steam generator.

[0018] As a further improvement of the present invention, the method further includes the following steps before step S4:

[0019] Obtain the safety margin α of the current state of the DC steam generator, and obtain the minimum safety margin αmin of the DC steam generator. The minimum safety margin αmin of the DC steam generator is the safety margin when water droplets or hot water are generated at the outlet of the DC steam generator.

[0020] When the difference between the safety margin α and the minimum safety margin αmin is within the set threshold, select the equal safety margin controller C2 and adjust the opening degree k of the feedwater regulating valve of the DC steam generator.

[0021] When the difference between the safety margin α and the minimum safety margin αmin is greater than the set threshold, select the equal steam pressure controller C1 to control the DC steam generator to work according to the set parameters.

[0022] As a further improvement of the present invention, the DC steam generator acquires the safety margin α and steam pressure p of the current state at every time t, and controls the operating parameters of the DC steam generator according to the difference between the safety margin α of the current state and the minimum safety margin αmin.

[0023] This application also includes a steam regulating device for a thermal system, used to control the steam output state of a direct-flow steam generator, wherein the direct-flow steam generator includes a closed container, the closed container including a water inlet and a steam outlet; it includes:

[0024] The water inlet is equipped with a water supply regulating valve, which is used to regulate the water flow rate entering the closed container;

[0025] The closed container is equipped with an equal steam pressure controller C1 and an equal safety margin controller C2. The equal steam pressure controller is used to obtain the steam pressure at the steam outlet end, and the equal safety margin controller is used to obtain the safety margin at the steam outlet end.

[0026] The control center is communicatively connected to the feedwater regulating valve, the equal steam pressure controller, and the equal safety margin controller. The control center can select either the equal steam pressure controller or the equal safety margin controller, and adjust the feedwater regulating valve according to the opening degree of the feedwater regulating valve calculated by the corresponding controller.

[0027] As a further improvement of the present invention, the equal steam pressure controller is provided with a steam pressure monitoring device, and the equal safety margin controller is provided with a steam superheat monitoring device.

[0028] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0029] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include:

[0030] (1) The steam regulation method for thermal systems of the present invention mainly adopts an equal steam pressure controller and an equal safety margin controller to coordinately regulate the opening of the feedwater regulating valve. When it is necessary to adjust the steam output of the thermal system, the equal steam pressure controller or the equal safety margin controller is selected according to the load and feedwater flow strain curve of the DC steam generator to achieve rapid regulation of steam output. The steam regulation method for thermal systems in this application adopts a coordinated control method of equal steam pressure controller and equal safety margin controller. It utilizes the characteristics of the equal steam pressure controller for rapid regulation and the equal safety margin controller for safe regulation, which can not only achieve rapid regulation of steam output of thermal systems, but also avoid the problem of water droplets or hot water generated at the steam outlet when regulating rapidly. The core of this application is to adopt the coordinated control of equal steam pressure controller and equal safety margin controller, so that the safety controller and performance controller of the DC steam generator can be designed separately and do not affect each other, thus removing the design constraints of safety on the performance controller, making the steam regulation process of thermal systems more convenient and efficient.

[0031] (2) The steam regulation method of the thermal system of the present invention sets a minimum safety margin αmin. If the difference between the current safety margin and the minimum safety margin is greater than the set threshold, there is no risk of water droplets or hot water being generated at the steam outlet, and the normal operation of the steam generating device can be maintained. If the difference between the current safety margin and the minimum safety margin is less than the set threshold, there is a risk of water droplets or hot water being generated at the steam outlet. At this time, it is necessary to adjust the opening of the feedwater regulating valve to ensure the stable operation of the thermal system. By setting the threshold, the number of times the feedwater regulating valve is adjusted can be reduced, ensuring the smooth operation of the thermal system. Attached Figure Description

[0032] Figure 1 This is a schematic flowchart of the steam regulation method for a thermal system in an embodiment of the present invention;

[0033] Figure 2 This is a graph showing the relationship between the load of the steam generator and the feedwater flow rate in an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of the structure of the steam regulating device of the thermal system in an embodiment of the present invention.

[0035] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically:

[0036] 1. DC steam generator; 2. Control center; 3. Steam pressure controller; 4. Safety margin controller. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0038] In the description of this invention, it should be understood that, unless otherwise stated, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0039] Furthermore, unless otherwise stated, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] Example:

[0043] Please see Figures 1-3 The steam regulation method for a thermal system in a preferred embodiment of the present invention includes the following steps:

[0044] S1. Under normal operating conditions, the standard steam pressure at the outlet of the DC steam generator 1 is p1, the standard steam superheat at the outlet of the DC steam generator 1 is ΔT1, the standard feedwater regulating valve opening is k1, and the standard feedwater flow rate is m. Here, the feedwater regulating valve opening and the feedwater flow rate are positively correlated, and the two do not need to be calculated separately.

[0045] S2. For the steam superheat at the outlet of the DC steam generator 1, the minimum superheat is determined to be ΔTmin. When the steam superheat at the outlet of the DC steam generator 1 is less than ΔTmin, the steam at the outlet of the DC steam generator 1 carries water droplets or hot water.

[0046] S3. Connect an equal steam pressure controller (C1) 3 and an equal safety margin controller (C2) 4 to the DC steam generator 1. The equal steam pressure controller 3 adjusts the opening of the feedwater regulating valve according to the steam pressure p, and the equal safety margin controller 4 adjusts the opening of the feedwater regulating valve according to the steam superheat ΔT.

[0047] S4. Select the equal steam pressure controller 3 or equal safety margin controller 4 according to the load and feedwater flow strain curve of the DC steam generator 1, so that there are no water droplets or hot water at the outlet of the DC steam generator 1; wherein, the load and feedwater flow strain curve of the DC steam generator 1 is the adjustment curve by adjusting the opening of the feedwater regulating valve to quickly adjust the DC steam generator 1 to the set steam outlet rate without producing water droplets or hot water.

[0048] S5. Obtain the opening degree k of the feedwater regulating valve according to the corresponding selected controller, and adjust the opening degree of the feedwater regulating valve of the DC steam generator 1 to regulate the steam output state of the thermal system.

[0049] The steam regulation method for thermal systems in this application mainly employs an equal steam pressure controller 3 and an equal safety margin controller 4 to collaboratively regulate the opening of the feedwater regulating valve. When it is necessary to adjust the steam output of the thermal system, the equal steam pressure controller 3 or the equal safety margin controller 4 is selected according to the load and feedwater flow strain curve of the direct-current steam generator 1 to achieve rapid regulation of the steam output. This method utilizes the characteristics of rapid regulation by the equal steam pressure controller 3 and the safe regulation by the equal safety margin controller 4, achieving rapid regulation of the steam output of the thermal system while avoiding the generation of water droplets or hot water at the steam outlet during rapid regulation. The core of this application lies in the collaborative control of the equal steam pressure controller 3 and the equal safety margin controller 4, allowing the safety controller and performance controller of the direct-current steam generator 1 to be designed separately without affecting each other. This removes the design constraints of safety on the performance controller, making the steam regulation process of the thermal system more convenient and efficient.

[0050] Specifically, the normal operating state in this application refers to the standard value set at the beginning of operation of the DC steam generator 1. The DC steam generator 1 operates using the same standard operating parameters in subsequent operations. The equal pressure controller in this application is mainly used to precisely control the pressure and maintain it stable at the set value. Meanwhile, the equal safety margin controller 4 in this application ensures that key parameters (such as temperature, pressure, flow rate, etc.) are maintained within a safe range during system operation, ensuring that the system has the same safety margin. It mainly monitors the key parameters of the system in real time and compares these parameters with preset safety limit values. When a parameter approaches the safety limit, the controller takes corresponding adjustment measures, such as adjusting the flow rate or changing the power, to ensure that the system's operating parameters are always kept within a safe range and that the safety margins of each part are approximately equal.

[0051] In this application, both the equal steam pressure controller 3 and the equal safety margin controller 4 achieve adjustment by regulating the opening of the feedwater regulating valve. When the equal steam pressure controller 3 is used to regulate the pressure, the opening of the feedwater regulating valve increases, the feedwater flow rate increases, and the steam pressure increases under the same volume. To maintain stable pressure, the steam outlet rate needs to be increased. At this time, the steam outlet rate can be quickly adjusted to the set requirement, and the pressure increases accordingly. The saturated steam temperature increases accordingly, and the superheat decreases accordingly, resulting in an increased probability of water vapor being generated at the steam outlet. That is, the equal steam pressure controller 3 can achieve rapid adjustment of the set steam outlet rate, but it may cause water droplets or hot water to be carried at the steam outlet. When the equal safety margin controller 4 is used to regulate the safety margin, the opening of the feedwater regulating valve increases, the pressure increases, the saturated steam temperature increases, and the superheat decreases. In order to maintain the equal safety margin, that is, to prevent water droplets or hot water from being generated at the steam outlet, the opening of the feedwater regulating valve needs to be reduced accordingly, that is, the steam outlet rate is adjusted to the set requirement at a slower pace. By analyzing the adjustment modes of the equal steam pressure controller 3 and the equal safety margin controller 4, it can be found that the equal steam pressure controller 3 has the advantage of a faster adjustment rate, but water droplets or hot water may be generated at the steam outlet; the equal safety margin controller 4 has the advantage of stable adjustment, ensuring that no water droplets or hot water are generated at the steam outlet, thus ensuring the safe and stable operation of downstream equipment, but its adjustment rate is relatively slower. Based on this, the steam regulation method for the thermal system in this application combines the equal steam pressure controller 3 and the equal safety margin controller 4. The equal steam pressure controller 3 achieves rapid adjustment of the steam rate, and when the safety margin approaches the minimum safety margin, the equal safety margin controller 4 can be switched for adjustment to avoid water droplets or hot water at the steam outlet, ensuring that the load and feedwater flow curve (load rise line) of the steam generator follows the boundary path of the water droplet-containing steam at the outlet. Figure 2 As shown. This steam regulation method for thermal systems can achieve rapid regulation of the steam rate while avoiding the problems of water droplets and hot water at the steam outlet.

[0052] Optionally, the load and feedwater flow strain curves of the DC steam generator 1 in this application include, but are not limited to, those in this application. Figure 2 The load increase line in the process can also be other curves that are not at the boundary of the outlet steam containing water droplets, as long as the curve is between the boundary of the outlet steam containing water droplets and the steady-state line, so that no water droplets or hot water are generated at the steam outlet of the DC steam generator 1.

[0053] Furthermore, as an optional embodiment of the present invention, the equal safety margin controller 4 in step S3 adjusts the opening of the feedwater regulating valve according to the safety margin α. Specifically, the safety margin α in this application is positively correlated with the steam superheat ΔT, and its calculation method is as follows:

[0054] α = ΔT / ΔTmin (Formula 1).

[0055] According to Formula 1, given the current steam superheat ΔT, ΔTmin represents the standard steam superheat, allowing direct calculation of the current safety margin α. Adjusting the feedwater regulating valve opening based on the safety margin α not only controls the equal safety margin controller 4 but also determines the current operating state of the direct-flow steam generator 1 based on the equal safety margin α and the minimum safety margin αmin, thus ensuring that no water droplets or hot water are generated at the steam outlet of the direct-flow steam generator 1.

[0056] Furthermore, as an optional embodiment of the present invention, the selection of the controller in step S4 of this application includes:

[0057] Obtain the current steam pressure p2, calculate the ratio of the current steam pressure p2 to the standard steam pressure p1, and obtain the first output signal u1;

[0058] Obtain the safety margin α2 under the current state, calculate the safety margin α1 under the standard state, calculate the ratio of the safety margin α2 under the current state to the safety margin α1 under the standard state, and obtain the second output signal u2;

[0059] The first output signal u1 and the second output signal u2 are compared, and the controller with the smaller output signal is used as the controller for the final adjustment of the DC steam generator 1.

[0060] Specifically, when adjusting the feedwater regulating valve opening using either the equal steam pressure controller 3 or the equal safety margin controller 4, the steam pressure p2 under the current state is obtained, and the equal steam pressure controller 3 calculates the corresponding feedwater regulating valve opening; the safety margin α2 under the current state is obtained, and the equal safety margin controller 4 calculates the corresponding feedwater regulating valve opening; then, the smaller of the first output signal u1 and the second output signal u2 is obtained. When the equal steam pressure controller 3 is selected, it represents adjusting to the set steam pressure, which results in a faster adjustment rate; when the equal safety margin controller 4 is selected, it represents adjusting to the set safety margin, which prevents water droplets or hot water from forming at the steam outlet. In the actual adjustment process, Figure 2 The load increase in the road section is often adjusted by the equal steam pressure controller 3 and the equal safety margin controller 4. That is, the equal steam pressure controller 3 is used for adjustment in some sections and the equal safety margin controller 4 is used for adjustment in other sections, taking into account both the adjustment rate and the adjustment safety.

[0061] Furthermore, as an optional embodiment of the present invention, step S4 in this application further includes the following:

[0062] Obtain the safety margin α of the current state of the DC steam generator 1, and obtain the minimum safety margin αmin of the DC steam generator 1. The minimum safety margin αmin of the DC steam generator 1 is the safety margin when water droplets or hot water are generated at the outlet of the DC steam generator 1.

[0063] When the difference between the safety margin α and the minimum safety margin αmin is within the set threshold, select the equal safety margin controller 4 and adjust the opening degree k of the feedwater regulating valve of the DC steam generator 1.

[0064] When the difference between the safety margin α and the minimum safety margin αmin is greater than the set threshold, the equal steam pressure controller 3 is selected, and the DC steam generator 1 operates according to the set parameters.

[0065] When adjusting the status of the DC steam generator 1, in addition to actively adjusting the opening of the feedwater regulating valve, there is also a passive demand adjustment. When the current safety margin α of the DC steam generator 1 is close to the minimum safety margin αmin, it means that there is a risk of water droplets and hot water being generated at the steam outlet. At this time, it is necessary to intervene in the equal safety margin controller 4 to adjust the safety margin α of the DC steam generator 1 to a safe range to ensure the normal operation of the thermal system.

[0066] Furthermore, as an optional embodiment of the present invention, the DC steam generator 1 in this application acquires the safety margin α of the current state at every time interval t, and controls the operating parameters of the DC steam generator 1 based on the difference between the safety margin α of the current state and the minimum safety margin αmin. Optionally, this application sets a time interval t, and then monitors and adjusts the operating state of the DC steam generator 1 to reduce the power consumption of the DC steam generator 1 and ensure the stable operation of the DC steam generator 1.

[0067] Furthermore, the steam regulation method for a thermal system in this application also includes a steam regulation device for controlling the steam output state of a direct-flow steam generator 1. The direct-flow steam generator 1 includes a closed container with a water inlet and a steam outlet. The steam regulation device for the thermal system includes:

[0068] The inlet end is equipped with a water supply regulating valve, which is used to regulate the water supply flow into the closed container;

[0069] The closed container is equipped with a steam pressure equalization controller 3 and a safety margin equalization controller 4. The steam pressure equalization controller 3 is used to obtain the steam pressure at the steam outlet and adjust the feedwater flow rate according to the steam pressure; the safety margin equalization controller 4 is used to obtain the safety margin at the steam outlet and adjust the feedwater flow rate according to the safety margin.

[0070] And control center 2, which is connected to feedwater regulating valve, equal steam pressure controller 3 and equal safety margin controller 4 respectively. Control center 2 can select equal steam pressure controller 3 or equal safety margin controller 4, and adjust feedwater regulating valve according to the opening degree of feedwater regulating valve calculated by the corresponding controller.

[0071] The steam regulation device of the thermal system mainly corresponds to the steam regulation method of the thermal system. It adjusts the feedwater flow rate into the closed container by adjusting the feedwater regulating valve, thereby providing feedback regulation of steam pressure, steam superheat, etc., to complete the regulation of steam rate. The equal steam pressure controller 3 and equal safety margin controller 4 are used to obtain the steam pressure and safety margin at the steam outlet, and calculate the opening degree of the feedwater regulating valve accordingly. The control center 2 completes the regulation of feedwater flow rate to achieve efficient operation of the thermal system.

[0072] Furthermore, as an optional embodiment of the present invention, the equal steam pressure controller 3 is equipped with a steam pressure monitoring device, and the equal safety margin controller 4 is equipped with a steam superheat monitoring device. The steam pressure monitoring device and the steam superheat monitoring device are mainly used to obtain the steam pressure and steam superheat at the steam outlet, thereby calculating and adjusting the opening degree of the feedwater regulating valve.

[0073] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A steam regulation method for a thermal system, characterized in that, Includes the following steps: S1. Under normal operating conditions, the standard steam pressure at the outlet of the DC steam generator is p1, the standard steam superheat at the outlet of the DC steam generator is ΔT1, the standard feedwater regulating valve opening is k1, and the standard feedwater flow rate is m. S2. For the steam superheat at the outlet of the DC steam generator, the minimum superheat is determined to be ΔTmin. When the steam superheat at the outlet of the DC steam generator is less than ΔTmin, the steam at the outlet of the DC steam generator carries water droplets or hot water. S3. Connect an equal steam pressure controller C1 and an equal safety margin controller C2 to the DC steam generator. The equal steam pressure controller C1 adjusts the opening of the feedwater regulating valve according to the steam pressure p, and the equal safety margin controller C2 adjusts the opening of the feedwater regulating valve according to the steam superheat ΔT. The load-feedwater flow strain curve of the DC steam generator is an adjustment curve that allows the DC steam generator to be quickly adjusted to the set steam outlet rate without producing water droplets or hot water by adjusting the opening of the feedwater regulating valve. S4. Select either an equal steam pressure controller C1 or an equal safety margin controller C2 based on the load and feedwater flow strain curve of the once-through steam generator to ensure that there are no water droplets or hot water at the outlet of the once-through steam generator; the selection of the controller includes: Obtain the current steam pressure p2, calculate the ratio of the current steam pressure p2 to the standard steam pressure p1, and obtain the first output signal u1; Obtain the safety margin α2 under the current state, calculate the safety margin α1 under the standard state, calculate the ratio of the safety margin α2 under the current state to the safety margin α1 under the standard state, and obtain the second output signal u2; Compare the first output signal u1 and the second output signal u2, and use the controller with the smaller output signal as the final controller for regulating the DC steam generator; S5. Obtain the opening degree k of the feedwater regulating valve according to the corresponding selected controller, and adjust the opening degree of the feedwater regulating valve of the DC steam generator to regulate the steam output state of the thermal system.

2. The steam regulation method for a thermal system according to claim 1, characterized in that, In step S3, the equal safety margin controller C2 adjusts the opening of the water supply regulating valve according to the safety margin α.

3. The steam regulation method for a thermal system according to claim 2, characterized in that, The safety margin α is calculated as follows: α = ΔT / ΔTmin (Formula 1).

4. The steam regulation method for a thermal system according to claim 1, characterized in that, The procedure preceding step S4 also includes: Obtain the safety margin α of the current state of the DC steam generator, and obtain the minimum safety margin αmin of the DC steam generator. The minimum safety margin αmin of the DC steam generator is the safety margin when water droplets or hot water are generated at the outlet of the DC steam generator. When the difference between the safety margin α and the minimum safety margin αmin is within the set threshold, select the equal safety margin controller C2 and adjust the opening degree k of the feedwater regulating valve of the DC steam generator. When the difference between the safety margin α and the minimum safety margin αmin is greater than the set threshold, select the equal steam pressure controller C1 to control the DC steam generator to work according to the set parameters.

5. The steam regulation method for a thermal system according to claim 4, characterized in that, The DC steam generator acquires the safety margin α and steam pressure p at every time interval t, and controls the operating parameters of the DC steam generator based on the difference between the current safety margin α and the minimum safety margin αmin.

6. A steam regulating device for a thermal system, operating the steam regulating method for a thermal system as described in any one of claims 1 to 5, for controlling the steam output state of a direct-flow steam generator, wherein the direct-flow steam generator comprises a closed container, the closed container comprising a water inlet end and a steam outlet end; characterized in that, include: The water inlet is equipped with a water supply regulating valve, which is used to regulate the water flow rate entering the closed container; The closed container is equipped with an equal steam pressure controller C1 and an equal safety margin controller C2. The equal steam pressure controller is used to obtain the steam pressure at the steam outlet end, and the equal safety margin controller is used to obtain the safety margin at the steam outlet end. The control center is communicatively connected to the feedwater regulating valve, the equal steam pressure controller, and the equal safety margin controller. The control center can select either the equal steam pressure controller or the equal safety margin controller, and adjust the feedwater regulating valve according to the opening degree of the feedwater regulating valve calculated by the corresponding controller.

7. The steam regulating device for a thermal system according to claim 6, characterized in that, The equal steam pressure controller is equipped with a steam pressure monitoring device, and the equal safety margin controller is equipped with a steam superheat monitoring device.

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