Thermal system steam adjusting device and adjusting method

Abstract

The invention discloses a thermotechnical system steam adjusting device and method, and belongs to the technical field of steam control. The method comprises the steps that the standard steam pressure, the standard steam superheat degree, the standard feed water adjusting valve opening degree and the standard feed water flow of an outlet of a once-through steam generating device are determined; determining the lowest superheat degree; an equal steam pressure controller and an equal safety margin controller are connected into the once-through steam generating device; selecting an equal steam pressure controller or an equal safety margin controller according to the load of the once-through steam generation device and the feed water flow strain curve; the opening degree of the water supply adjusting valve is obtained according to the correspondingly selected controller, and the steam output state of the thermal system is adjusted by adjusting the opening degree of the water supply adjusting valve. The equal steam pressure controller and the equal safety margin controller are adopted for cooperative control, so that the safety controller and the performance controller of the once-through steam generation device can be designed separately and do not affect each other, the design constraint of safety on the performance controller is relieved, and the steam adjusting process of a thermal system is efficient and convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of steam control, and in particular relates to a steam regulating device and a regulating method for a thermal system. Background Art

[0002] The direct current steam generator is one of the main equipment of the thermal system in the heating field. Its main function is to transfer external heat to the feed water of the steam generator to turn it into steam of a certain temperature and pressure. The direct current steam generator has a relatively small heat storage and water storage capacity, and responds quickly to power changes; the small heat storage and water storage capacity also makes the outlet steam parameters more sensitive and fluctuates more widely, and the requirements for the direct current steam generator control system will also be more stringent.

[0003] When adjusting the outlet steam pressure of a direct current steam generator, when the outlet steam pressure is lower than the control command value, increase the opening of the feedwater regulating valve to increase the feedwater flow rate, increase the outlet steam flow rate, and thus increase the pressure; conversely, reduce the pressure. The external heating or heat exchange process of a direct current steam generator has a large thermal inertia. When the load is increased rapidly, if the feedwater flow rate increases too quickly, the heating capacity of the steam generator will not be able to match the heat exchange demand on the feedwater side, resulting in insufficient heat for vaporization on the feedwater side, resulting in water droplets at the outlet of the direct current steam generator, or even hot water, affecting the safe operation of steam-using equipment. Summary of the invention

[0004] In view of one or more of the above defects or improvement needs of the prior art, the present invention provides a steam regulation method for a thermal system, which is used to solve the problem that the outlet steam of the existing direct current steam generating device is easily accompanied by water droplets and even produces hot water.

[0005] To achieve the above object, the present invention provides a method for regulating steam in a thermal system, which comprises the following steps: S1. Determine that under normal working conditions, the outlet standard steam pressure of the once-through steam generator is p1, the standard steam superheat degree at the outlet of the once-through 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 direct current steam generator, the minimum superheat is determined to be ΔTmin. When the steam superheat at the outlet of the direct current steam generator is less than ΔTmin, the steam at the outlet of the direct current steam generator carries water droplets or hot water; S3. Connecting a steam pressure controller C1 and a safety margin controller C2 to the direct current steam generating device, wherein the steam pressure controller C1 adjusts the opening of the feed water regulating valve according to the steam pressure p, and the safety margin controller C2 adjusts the opening of the feed water regulating valve according to the steam superheat ΔT; the load and feed water flow strain curve of the direct current steam generating device is an adjustment curve for quickly adjusting the direct current steam generating device to a set steam outlet rate without generating water droplets or hot water by adjusting the opening of the feed water regulating valve; S4. Selecting an equal steam pressure controller C1 or an equal safety margin controller C2 according to the load and feed water flow strain curve of the direct current steam generating device, so that there is no water drop or hot water in the steam at the outlet of the direct current steam generating device; S5. Obtain the feedwater regulating valve opening k according to the corresponding selected controller, and adjust the feedwater regulating valve opening of the direct current steam generating device to adjust the steam output state of the thermal system.

[0006] 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.

[0007] As a further improvement of the present invention, the safety margin α is calculated as follows: α=ΔT / ΔTmin (Formula 1).

[0008] As a further improvement of the present invention, the selection of the controller in step S4 includes: Obtain the steam pressure p2 in the current state, calculate the ratio of the steam pressure p2 in the current state to the standard steam pressure p1, and obtain the first output signal u1; Obtain the safety margin α2 in the current state, calculate the safety margin α1 in the standard state, calculate the ratio of the safety margin α2 in the current state to the safety margin α1 in the standard state, and obtain the second output signal u2; 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 finally adjusting the direct current steam generating device.

[0009] As a further improvement of the present invention, before step S4, the following steps are further included: Obtaining a safety margin α of the current state of the direct current steam generating device, and obtaining a minimum safety margin αmin of the direct current steam generating device, wherein the minimum safety margin αmin of the direct current steam generating device is a safety margin when water droplets or hot water are generated at the outlet of the direct current steam generating device; When the difference between the safety margin α and the minimum safety margin αmin is within the set threshold, the equal safety margin controller C2 is selected and the feedwater regulating valve opening k of the once-through steam generating device is adjusted; 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 C1 is selected to control the once-through steam generating device to operate according to the set parameters.

[0010] As a further improvement of the present invention, the direct current steam generating device obtains the safety margin α and steam pressure p of the current state at every time t, and controls the working parameters of the direct current steam generating device according to the difference between the safety margin α of the current state and the minimum safety margin αmin.

[0011] The present application also includes a thermal system steam regulating device for controlling the steam output state of a direct current steam generating device, wherein the direct current steam generating device includes a closed container, wherein the closed container includes a water inlet end and a steam outlet end; the device includes: The water inlet end is provided with a water supply regulating valve, and the water supply regulating valve is used to adjust the water supply flow entering the closed container; The closed container is provided with an iso-steam pressure controller C1 and an iso-safety margin controller C2, wherein the iso-steam pressure controller is used to obtain the steam pressure at the steam outlet, and the iso-safety margin controller is used to obtain the safety margin at the steam outlet; A control center, wherein the control center is respectively connected to the feed water regulating valve, the equal steam pressure controller and the equal safety margin controller in communication, and the control center can select the equal steam pressure controller or the equal safety margin controller, and adjust the feed water regulating valve according to the feed water regulating valve opening calculated by the corresponding controller.

[0012] As a further improvement of the present invention, a steam pressure monitoring device is provided in the equal steam pressure controller, and a steam superheat monitoring device is provided in the equal safety margin controller.

[0013] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0014] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects: (1) The steam regulation method for a thermal system of the present invention mainly adopts an equal steam pressure controller and an equal safety margin controller to coordinately adjust the opening of the feed water regulating valve. When the steam output of the thermal system needs to be adjusted, the equal steam pressure controller or the equal safety margin controller is selected according to the load and feed water flow strain curve of the direct current steam generating device to achieve rapid regulation of the steam output. The steam regulation method for a thermal system in the present application adopts the coordinated control method of the equal steam pressure controller and the equal safety margin controller, and utilizes the characteristics of the equal steam pressure controller for fast regulation and the equal safety margin controller for safe regulation, which can not only achieve rapid regulation of the steam output of the thermal system, but also avoid the problem of water droplets or hot water generated at the steam outlet when the regulation is fast. The core of the present application is to adopt the coordinated control of the equal steam pressure controller and the equal safety margin controller, so that the safety controller and the performance controller of the direct current steam generating device can be designed separately without affecting each other, thereby eliminating the design constraints of the performance controller on the safety, and making the steam regulation process of the thermal system more convenient and efficient.

[0015] (2) The steam regulation method for a 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 water supply regulating valve to ensure the stable operation of the thermal system. By setting the threshold, the number of times the water supply regulating valve is adjusted can be reduced to ensure the smooth operation of the thermal system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 1 is a schematic flow chart of a method for regulating steam in a thermal system according to an embodiment of the present invention; Figure 2 is a curve diagram showing the relationship between the load of the steam generating device and the feed water flow rate in an embodiment of the present invention; Figure 3 It is a schematic diagram of the structure of a steam regulating device for a thermal system in an embodiment of the present invention.

[0017] In all the drawings, the same reference numerals represent the same technical features, specifically: 1. Direct current steam generating device; 2. Control center; 3. Equal steam pressure controller; 4. Equal safety margin controller. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0019] In the description of the present invention, it should be understood that, unless otherwise specified, terms such as “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0020] In addition, unless otherwise specified, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0023] Example: See also Figures 1 to 3 The steam regulation method for a thermal system in a preferred embodiment of the present invention comprises the following steps: S1. Determine that under normal working conditions, the outlet standard steam pressure of the direct current steam generating device 1 is p1, the standard steam superheat of the direct current steam generating device 1 outlet is ΔT1, the standard feed water regulating valve opening is k1, and the standard feed water flow rate is m; here, the feed water regulating valve opening is positively correlated with the feed water flow rate, and the two do not need to be calculated separately.

[0024] S2. For the steam superheat at the outlet of the direct current steam generating device 1, the minimum superheat is determined to be ΔTmin. When the steam superheat at the outlet of the direct current steam generating device 1 is less than ΔTmin, the steam at the outlet of the direct current steam generating device 1 carries water droplets or hot water; S3, connecting an equal steam pressure controller (C1) 3 and an equal safety margin controller (C2) 4 to the direct current steam generating device 1, wherein the equal steam pressure controller 3 adjusts the opening of the feed water regulating valve according to the steam pressure p, and the equal safety margin controller 4 adjusts the opening of the feed water regulating valve according to the steam superheat ΔT; S4, selecting the equal steam pressure controller 3 or the equal safety margin controller 4 according to the load and feed water flow strain curve of the direct current steam generating device 1, so that there is no water drop or hot water in the steam at the outlet of the direct current steam generating device 1; wherein the load and feed water flow strain curve of the direct current steam generating device 1 is an adjustment curve for quickly adjusting the direct current steam generating device 1 to a set steam outlet rate without generating water drop or hot water by adjusting the opening of the feed water regulating valve; S5. Obtain the feedwater regulating valve opening k according to the corresponding selected controller, and adjust the feedwater regulating valve opening of the direct current steam generating device 1 to adjust the steam output state of the thermal system.

[0025] The steam regulation method for a thermal system in the present application mainly adopts an equal steam pressure controller 3 and an equal safety margin controller 4 to coordinately adjust the opening of the feed water regulating valve. When the steam output of the thermal system needs to be adjusted, the equal steam pressure controller 3 or the equal safety margin controller 4 is selected according to the load and feed water flow strain curve of the direct current steam generating device 1 to achieve rapid regulation of the steam output. The steam regulation method for a thermal system in the present application adopts the coordinated control method of the equal steam pressure controller 3 and the equal safety margin controller 4, and utilizes the characteristics of the equal steam pressure controller 3 being fast to adjust and the equal safety margin controller 4 being safe to adjust, which can not only achieve rapid regulation of the steam output of the thermal system, but also avoid the problem of water droplets or hot water being generated at the steam outlet when the adjustment is fast. The core of the present application is to adopt the coordinated control of the equal steam pressure controller 3 and the equal safety margin controller 4, so that the safety controller and the performance controller of the direct current steam generating device 1 can be designed separately without affecting each other, thereby removing the design constraints of the safety on the performance controller, and making the steam regulation process of the thermal system more convenient and efficient.

[0026] Specifically, the normal working state in the present application refers to the standard value set at the beginning of the operation of the direct current steam generator 1, and the direct current steam generator 1 operates with the same standard working parameters in subsequent operations. The equal pressure controller in the present application is mainly used to accurately control the pressure and keep the pressure stable at the set value. At the same time, the equal safety margin controller 4 in the present application is mainly to ensure that key parameters (such as temperature, pressure, flow, etc.) are maintained within a safe range during the operation of the system, and the system has the same safety margin. It mainly monitors the key parameters of the system in real time and compares these parameters with the preset safety limit values. When the parameters are close to the safety limit, the controller will take corresponding adjustment measures, such as adjusting the flow, changing the power, etc., to ensure that the operating parameters of the system are always kept within the safety range, and the safety margins of each part are roughly equal.

[0027] For the present application, the equal steam pressure controller 3 and the equal safety margin controller 4 in the present application are both adjusted by adjusting the opening of the feed water regulating valve. When the equal steam pressure controller 3 is used to adjust the pressure, the opening of the feed water regulating valve increases, the feed water flow increases, and the steam pressure increases under the same volume. To maintain the pressure stability, the steam outlet rate needs to be increased. At this time, the steam outlet rate can be quickly adjusted to the set demand, and the pressure increases accordingly, the saturated steam temperature increases accordingly, and the superheat decreases accordingly, resulting in an increase in the probability of water vapor 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 adjust the safety margin, the opening of the feed water 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, no water droplets or hot water are generated at the steam outlet, it is necessary to reduce the opening of the feed water regulating valve accordingly, that is, the steam outlet rate is adjusted to the set demand speed reduction. 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 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, which can ensure that no water droplets or hot water are generated at the steam outlet, and can ensure the safe and stable operation of subsequent equipment, but the adjustment rate is relatively slow. Based on this, the thermal system steam regulation method in the present application combines the equal steam pressure controller 3 and the equal safety margin controller 4, and realizes rapid adjustment of the steam rate through the equal steam pressure controller 3. When the safety margin is close to 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, and ensure that the steam generating device load and water supply flow curve (load increase line) is close to the outlet steam water droplet boundary behavior, such as Figure 2 The steam regulation method of the thermal system can not only realize the rapid regulation of the steam rate, but also avoid the problem of water droplets and hot water at the steam outlet.

[0028] Optionally, the load and feedwater flow strain curve of the direct current steam generating device 1 in the present application includes but is not limited to the load and feedwater flow strain curve of the present application Figure 2 The load-increasing line in the figure may also be other curves that are not in contact with 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 direct-current steam generating device 1.

[0029] Further, as an optional embodiment of the present invention, the equal safety margin controller 4 in step S3 of the present application adjusts the opening of the feedwater regulating valve according to the safety margin α. Specifically, the safety margin α in the present application is positively correlated with the steam superheat ΔT, and its calculation method is: α=ΔT / ΔTmin (Formula 1).

[0030] According to Formula 1, in the present application, when the steam superheat ΔT in the current state is known, ΔTmin is the standard steam superheat, from which the safety margin α of the current state can be directly obtained. The method of adjusting the opening of the feedwater regulating valve according to the safety margin α can not only realize the control of the equal safety margin controller 4, but also can judge the current working state of the direct current steam generator 1 according to the equal safety margin α and the minimum safety margin αmin, so as to ensure that the steam outlet of the direct current steam generator 1 will not produce water droplets or hot water.

[0031] Further, as an optional embodiment of the present invention, the selection of the controller in step S4 of the present application includes: Obtain the steam pressure p2 in the current state, calculate the ratio of the steam pressure p2 in the current state to the standard steam pressure p1, and obtain the first output signal u1; Obtain the safety margin α2 in the current state, calculate the safety margin α1 in the standard state, calculate the ratio of the safety margin α2 in the current state to the safety margin α1 in the standard state, and obtain the second output signal u2; 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 finally adjusting the direct-flow steam generating device 1 .

[0032] Specifically, when it is necessary to use the equal steam pressure controller 3 or the equal safety margin controller 4 to adjust the opening of the water supply regulating valve, obtain the steam pressure p2 in the current state, and the equal steam pressure controller 3 calculates the opening of the water supply regulating valve accordingly; obtain the safety margin α2 in the current state, and the equal safety margin controller 4 calculates the opening of the water supply regulating valve accordingly; then calculate the first output signal u1 and the second output signal u2 to obtain the smaller value of the two. When the equal steam pressure controller 3 is selected, it means that the steam pressure is adjusted to the set steam pressure, and the adjustment rate is faster at this time; when the equal safety margin controller 4 is selected, it means that the steam pressure is adjusted to the set safety margin, and water droplets or hot water will not be generated at the steam outlet. In the actual adjustment process, Figure 2 The load increase in the process is often formed by adjusting the equal steam pressure controller 3 and the equal safety margin controller 4 together, that is, some sections are adjusted by the equal steam pressure controller 3, and some sections are adjusted by the equal safety margin controller 4, taking into account both the adjustment rate and the adjustment safety.

[0033] Further, as an optional embodiment of the present invention, before step S4 in the present application, the following steps are also included: Obtaining a safety margin α of the current state of the direct current steam generating device 1, and obtaining a minimum safety margin αmin of the direct current steam generating device 1, wherein the minimum safety margin αmin of the direct current steam generating device 1 is a safety margin when water droplets or hot water are generated at the outlet of the direct current steam generating device 1; When the difference between the safety margin α and the minimum safety margin αmin is within the set threshold, the equal safety margin controller 4 is selected, and the opening k of the feedwater regulating valve of the once-through steam generating device 1 is adjusted; 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 direct current steam generating device 1 operates according to the set parameters.

[0034] When adjusting the state of the direct 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 direct steam generator 1 is close to the minimum safety margin αmin, it means that there is a risk of water droplets and hot water at the steam outlet. At this time, the safety margin controller 4 needs to intervene to adjust the safety margin α of the direct steam generator 1 to a safe range to ensure the normal operation of the thermal system.

[0035] Further, as an optional embodiment of the present invention, the DC steam generator 1 in the present application obtains the safety margin α of the current state at every time t, and controls the working parameters of the DC steam generator 1 according to the difference between the safety margin α of the current state and the minimum safety margin αmin. Optionally, the present application sets the time interval t, and then monitors and adjusts the working 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.

[0036] Furthermore, with respect to the thermal system steam regulation method in the present application, it also includes a thermal system steam regulation device, which is used to control the steam output state of the direct current steam generating device. The direct current steam generating device 1 includes a closed container, and the closed container includes a water inlet end and a steam outlet end; the thermal system steam regulation device includes: A water supply regulating valve is provided at the water inlet end, and the water supply regulating valve is used to adjust the water supply flow entering the closed container; The closed container is provided with an equal steam pressure controller 3 and an equal safety margin controller 4. The equal steam pressure controller 3 is used to obtain the steam pressure at the steam outlet end and adjust the feed water flow rate according to the steam pressure; the equal safety margin controller 4 is used to obtain the safety margin at the steam outlet end and adjust the feed water flow rate according to the safety margin; And a control center 2, which is respectively communicated with the water supply regulating valve, the equal steam pressure controller 3 and the equal safety margin controller 4. The control center 2 can select the equal steam pressure controller 3 or the equal safety margin controller 4, and adjust the water supply regulating valve according to the opening of the water supply regulating valve calculated by the corresponding controller.

[0037] The steam regulating device of the thermal system mainly corresponds to the steam regulating method of the thermal system. The feed water flow entering the closed container is adjusted through the feed water regulating valve, so as to feedback and adjust the steam pressure, steam superheat, etc. to complete the steam rate regulation; the equal steam pressure controller 3 and the equal safety margin controller 4 are used to obtain the steam pressure and safety margin at the steam outlet, and calculate the opening of the feed water regulating valve accordingly. The feed water flow is regulated through the control center 2 to realize the efficient operation of the thermal system.

[0038] Further, as an optional embodiment of the present invention, a steam pressure monitoring device is provided in the equal steam pressure controller 3 in the present application, and a steam superheat monitoring device is provided in the equal safety margin controller 4. The steam pressure monitoring device and the steam superheat monitoring device are mainly used to obtain the steam pressure and steam superheat of the steam outlet, so as to calculate and adjust the opening of the feed water regulating valve.

[0039] It will be easily understood by those skilled in the art that the above description is only 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 in the protection scope of the present invention.

Claims

1. A method for regulating steam in a thermal system, characterized in that: The steps include: S1. Determine that under normal working conditions, the outlet standard steam pressure of the once-through steam generator is p1, the standard steam superheat degree at the outlet of the once-through 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 direct current steam generator, the minimum superheat is determined to be ΔTmin. When the steam superheat at the outlet of the direct current steam generator is less than ΔTmin, the steam at the outlet of the direct current steam generator carries water droplets or hot water; S3. Connecting a steam pressure controller C1 and a safety margin controller C2 to the direct current steam generating device, wherein the steam pressure controller C1 adjusts the opening of the feed water regulating valve according to the steam pressure p, and the safety margin controller C2 adjusts the opening of the feed water regulating valve according to the steam superheat ΔT; the load and feed water flow strain curve of the direct current steam generating device is an adjustment curve for quickly adjusting the direct current steam generating device to a set steam outlet rate without generating water droplets or hot water by adjusting the opening of the feed water regulating valve; S4. Selecting an equal steam pressure controller C1 or an equal safety margin controller C2 according to the load and feed water flow strain curve of the direct current steam generating device, so that there is no water drop or hot water in the steam at the outlet of the direct current steam generating device; S5. Obtain the feedwater regulating valve opening k according to the corresponding selected controller, and adjust the feedwater regulating valve opening of the direct current steam generating device to adjust the steam output state of the thermal system.

2. The method for regulating steam in 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 method for regulating steam in 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 method for regulating steam in a thermal system according to claim 3, characterized in that: The selection of the controller in step S4 includes: Obtain the steam pressure p2 in the current state, calculate the ratio of the steam pressure p2 in the current state to the standard steam pressure p1, and obtain the first output signal u1; Obtain the safety margin α2 in the current state, calculate the safety margin α1 in the standard state, calculate the ratio of the safety margin α2 in the current state to the safety margin α1 in the standard state, and obtain the second output signal u2; 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 finally adjusting the direct current steam generating device.

5. The method for regulating steam in a thermal system according to claim 1, characterized in that: Before step S4, the following steps are also included: Obtaining a safety margin α of the current state of the direct current steam generating device, and obtaining a minimum safety margin αmin of the direct current steam generating device, wherein the minimum safety margin αmin of the direct current steam generating device is a safety margin when water droplets or hot water are generated at the outlet of the direct current steam generating device; When the difference between the safety margin α and the minimum safety margin αmin is within the set threshold, the equal safety margin controller C2 is selected and the feedwater regulating valve opening k of the once-through steam generating device is adjusted; 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 C1 is selected to control the once-through steam generating device to operate according to the set parameters.

6. The method for regulating steam in a thermal system according to claim 5, characterized in that: The once-through steam generating device obtains the safety margin α and steam pressure p of the current state at every time t, and controls the working parameters of the once-through steam generating device according to the difference between the safety margin α of the current state and the minimum safety margin αmin.

7. A steam regulating device for a thermal system, used for controlling the steam output state of a direct current steam generating device, wherein the direct current steam generating device comprises a closed container, wherein the closed container comprises a water inlet end and a steam outlet end; characterized in that: include: The water inlet end is provided with a water supply regulating valve, and the water supply regulating valve is used to adjust the water supply flow entering the closed container; The closed container is provided with an iso-steam pressure controller C1 and an iso-safety margin controller C2, wherein the iso-steam pressure controller is used to obtain the steam pressure at the steam outlet, and the iso-safety margin controller is used to obtain the safety margin at the steam outlet; A control center, wherein the control center is respectively connected to the feed water regulating valve, the equal steam pressure controller and the equal safety margin controller in communication, and the control center can select the equal steam pressure controller or the equal safety margin controller, and adjust the feed water regulating valve according to the feed water regulating valve opening calculated by the corresponding controller.

8. The thermal system steam conditioning device according to claim 7, characterized in that: 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.

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