Molten salt heating direct-flow type wet saturated steam generation system

Abstract

A molten salt heating direct-flow type wet saturated steam generation system, comprising an evaporation device, a molten salt conveying device, a preheating device, a softened water conveying device, and a dryness adjustment device. The evaporation device is provided with a first heat exchange pipeline and a second heat exchange pipeline; the molten salt conveying device comprises a molten salt conveying apparatus and a molten salt recovery apparatus; the preheating device is provided with a first preheating pipeline, and an outlet of the second heat exchange pipeline is connected to a steam output pipeline; and the dryness adjustment device comprises an adjustment member and a dryness measurement apparatus. According to the steam generation system provided by the present invention, the temperature of softened water and the temperature of molten salt can be adjusted to appropriate ranges, avoiding the crystallization of the molten salt; moreover, the dryness of wet saturated steam can be controlled by means of coarse adjustment and fine adjustment, and the direct-flow type evaporation device is suitable for softened water having poor quality so as to meet the steam injection requirements of oil fields.

Description

Molten salt heating once-through wet saturated steam generation system

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application No. 202311330136.4 filed on October 13, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of oil field steam injection, in particular to a molten salt heating once-through wet saturated steam generating system. Background Art

[0004] In some oilfield production systems, natural gas consumption accounts for 88.8% of total energy consumption, primarily for heavy oil thermal recovery and steam injection, making it a key energy consumer. To meet the dual carbon goals, efforts are underway to explore the use of electric molten salt thermal storage technology to replace natural gas consumption, achieving the goal of "replacing natural gas with off-peak electricity / green electricity." This technology, when implemented, can reduce CO2 emissions while fully utilizing off-peak electricity / green electricity, alleviating pressure on the power grid. The application of molten salt energy storage technology in concentrated solar thermal power generation dates back to the 1980s. Molten salt serves as both a heat transfer medium and a heat storage medium. Existing molten salt energy storage technology is used in power generation, primarily in systems that produce superheated steam. Some molten salt energy storage technology is also used for steam generation. However, current steam generation systems incorporating molten salt energy storage technology mostly use pure water. However, the water used in heavy oil steam injection systems in oilfields often contains high silicon, mineralization, and chloride content, and requires the production of wet saturated steam of a certain dryness. Current steam generation systems incorporating molten salt energy storage technology cannot meet these requirements.

[0005] Summary of the Invention

[0006] In order to solve the technical problem that the current steam generation system cannot meet the poor water quality of the steam injection system in heavy oil fields and needs to produce wet saturated steam with a certain dryness, the present invention provides a molten salt heated once-through wet saturated steam generation system.

[0007] The present invention provides a molten salt heated once-through wet saturated steam generating system, comprising:

[0008] An evaporation device having a first heat exchange pipe and a second heat exchange pipe;

[0009] a molten salt delivery device, comprising a molten salt delivery device in communication with the inlet of the first heat exchange pipe and a molten salt recovery device in communication with the outlet of the first heat exchange pipe, wherein the molten salt delivery device is configured to adjust the temperature and flow rate of the molten salt entering the first heat exchange pipe;

[0010] a preheating device comprising a first preheating pipe in communication with the inlet of the second heat exchange pipe, the outlet of the second heat exchange pipe being connected to a steam output pipe, the preheating device being configured to preheat the liquid in the first preheating pipe and to adjust the temperature of the fluid output through the first preheating pipe;

[0011] a softened water delivery device, configured to deliver softened water into the first preheating pipe, wherein the softened water delivery device is configured to adjust the flow rate of the softened water delivered into the first preheating pipe;

[0012] The dryness regulating device includes a regulating member and a dryness detecting device provided on the steam delivery pipeline. The regulating member is configured to regulate the dryness of the wet saturated steam obtained after the fluid passes through the evaporation device after heat exchange based on the dryness information of the wet saturated steam fed back by the dryness detecting device.

[0013] Optionally, the molten salt conveying device includes a molten salt storage tank, a molten salt conveying pipeline and a first flow regulating device. The molten salt conveying pipeline is provided with a molten salt pump. The first flow regulating device is used to adjust the operating frequency of the molten salt pump.

[0014] Optionally, the first flow regulating device includes a molten salt flowmeter arranged on the molten salt delivery pipeline and a frequency converter electrically connected to the molten salt pump, and the frequency converter is configured to adjust the operating frequency of the molten salt pump according to the flow information fed back by the molten salt flowmeter.

[0015] Optionally, the softened water delivery equipment includes a liquid storage tank, a liquid delivery pipeline and a second flow regulating device, the liquid delivery pipeline is provided with a delivery pump, and the second flow regulating device is used to adjust the opening of the delivery pump.

[0016] Optionally, the second flow regulating device includes a liquid flow meter provided on the liquid delivery pipeline, and the delivery pump is configured to be able to adjust the opening of the delivery pump according to flow information fed back by the liquid flow meter.

[0017] Optionally, the preheating device further has a second preheating pipe, the inlet of the second preheating pipe is connected to the steam output pipe, and the outlet of the second preheating pipe is connected to the softened water delivery device.

[0018] Optionally, the preheating device further includes a condensate delivery pipe and a condensate regulating valve provided on the condensate delivery pipe, the outlet of the second preheating pipe is connected to the softened water delivery device through the condensate delivery pipe, and is configured as follows:

[0019] The temperature of the fluid output from the first preheating pipe can be adjusted by adjusting the opening of the condensed water regulating valve.

[0020] Optionally, the preheating equipment also includes a first temperature detection device for detecting the temperature of the fluid flowing out through the outlet of the first preheating pipe, the first temperature detection device is electrically connected to the condensate regulating valve, and the condensate regulating valve is configured to be able to adjust the opening of the condensate regulating valve according to the temperature information feedback from the first temperature detection device.

[0021] Optionally, the steam output pipe is connected to the inlet of the second preheating pipe through a return pipe, and a steam delivery device is connected to the return pipe.

[0022] Optionally, the evaporation device includes an evaporator,

[0023] The first heat exchange pipe includes a first evaporation pipe arranged inside the evaporator, the inlet of the first evaporation pipe is connected to the molten salt conveying device, and the outlet of the first evaporation pipe is connected to the molten salt recovery device;

[0024] The second heat exchange pipe includes a second evaporation pipe arranged in the evaporator, the inlet of the second evaporation pipe is connected to the outlet of the first preheating pipe, and the outlet of the second evaporation pipe is connected to the steam output pipe.

[0025] Optionally, the evaporation device further comprises a heater,

[0026] The first heat exchange pipe further includes a first heating pipe disposed inside the heater, the inlet of the first heating pipe being connected to the outlet of the first evaporation pipe, and the outlet of the first heating pipe being connected to the molten salt recovery device;

[0027] The second heat exchange pipe further includes a second heating pipe disposed inside the heater, the inlet of the second heating pipe being communicated with the outlet of the first preheating pipe, and the outlet of the second heating pipe being communicated with the inlet of the second evaporation pipe.

[0028] Optionally, the molten salt conveying equipment further includes a molten salt bypass pipeline, the inlet of the molten salt bypass pipeline is connected to the molten salt conveying device, the outlet of the molten salt bypass pipeline is connected to the outlet of the first evaporation pipe, and the molten salt bypass pipeline is provided with a first regulating valve for adjusting the molten salt flow rate.

[0029] Optionally, the molten salt conveying equipment further includes a second temperature detection device for detecting the temperature of the molten salt flowing out of the first evaporation pipe, the first regulating valve is electrically connected to the second temperature detection device, and the first regulating valve is configured to be able to adjust the opening of the first regulating valve according to temperature information fed back by the second temperature detection device.

[0030] Optionally, the regulating component includes a softened water bypass pipeline and a second regulating valve arranged on the softened water bypass pipeline, the inlet of the softened water bypass pipeline is connected to the outlet of the first preheating pipeline, and the outlet of the softened water bypass pipeline is connected to the inlet of the second evaporation pipeline, and the second regulating valve is configured to be able to adjust the opening of the second regulating valve according to the dryness information of the wet saturated steam fed back by the dryness detection device.

[0031] Optionally, the outlet of the first preheating pipe is further connected to a diversion pipe, and the diversion pipe is provided with a third regulating valve for adjusting the flow rate of softened water.

[0032] Optionally, the molten salt heated once-through wet saturated steam generating system further includes a pressure relief device, which is configured to release the fluid and superheated steam in the evaporation device when the softened water delivery device stops working.

[0033] Optionally, the pressure relief device includes a pressure relief pipe connected to the outlet of the first preheating pipe and a first pressure relief valve arranged on the pressure relief pipe, the first pressure relief valve is configured to open when the softened water delivery device stops delivering softened water, and the evaporation device is configured so that when the first pressure relief valve is opened, the fluid in the second heat exchange pipe can flow to the pressure relief pipe.

[0034] Optionally, the outlet of the pressure relief pipe is connected to a discharge expansion tank.

[0035] Optionally, the pressure relief device includes an exhaust pipe connected to the steam output pipe and a second pressure relief valve arranged on the exhaust pipe, and the second pressure relief valve is configured to open when the pressure in the steam output pipe is lower than a preset pressure.

[0036] Optionally, a pressure detection device for detecting the pressure of the circulating wet saturated steam is provided on the steam output pipeline, and the pressure detection device is electrically connected to the second pressure relief valve and is configured as follows:

[0037] When the pressure detection device detects that the pressure of the wet saturated steam is lower than the preset pressure, the second pressure relief valve opens.

[0038] The technical solution provided by the embodiments of the present invention has the following advantages compared with the prior art:

[0039] In the molten salt heated direct current wet saturated steam generating system provided by the present invention, softened water first enters the preheating device for preheating, and then flows to the second heat exchange pipe. The preheating device can adjust the temperature of the preheated softened water entering the second heat exchange pipe. At the same time, the molten salt conveying device can adjust the temperature of the molten salt entering the first heat exchange pipe, so as to adjust the softened water temperature and the molten salt temperature to the applicable range respectively, thereby avoiding the phenomenon of molten salt crystallization caused by the molten salt temperature being too low after heat exchange, thereby avoiding the blockage of the first heat exchange pipe, reducing the maintenance frequency of the steam generating system and the service life of the steam generating system; in addition, it can The flow rate of molten salt delivery and the flow rate of softened water delivery can be adjusted respectively through the molten salt delivery equipment and the softened water delivery equipment, thereby realizing the coarse adjustment of the dryness of the wet saturated steam obtained after heat exchange and evaporation by the evaporation equipment, and then adjusting the dryness of the wet saturated steam according to the dryness information of the wet saturated steam fed back by the dryness detection device through the adjustment component, thereby realizing the fine adjustment of the dryness of the wet saturated steam. Through the two adjustments, the dryness of the wet saturated steam can be accurately controlled. In addition, the steam generating system of the present application adopts a direct current evaporation equipment, which can be suitable for the characteristics of high silicon content, high chlorine content, and high mineralization of softened water in oil fields, so as to meet the steam injection requirements of oil fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0042] FIG1 is a schematic structural diagram of a molten salt heated once-through wet saturated steam generating system according to an embodiment of the present invention.

[0043] Explanation of the accompanying symbols 1. Evaporation equipment; 11. Evaporator; 12. Heater; 2. Molten salt conveying equipment; 21. Molten salt conveying pipeline; 22. Molten salt pump; 23. Molten salt flowmeter; 24. Frequency converter; 25. Molten salt bypass pipeline; 3. Preheating equipment; 31. Condensate conveying pipeline; 32. Condensate regulating valve; 4. Softened water conveying equipment; 41. Liquid storage tank; 42. Liquid conveying pipeline; 43. Conveying pump; 44. Liquid flowmeter; 5. Steam output pipeline; 51. Dryness detection device; 52. Pressure detection device; 6. Return pipeline; 61. Steam conveying equipment; 7. Softened water bypass pipeline; 71. Second regulating valve; 8. Pressure relief pipeline; 81. First pressure relief valve; 82. Discharge expansion tank; 9. Exhaust pipeline; 91. Second pressure relief valve. DETAILED DESCRIPTION

[0044] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0045] The following description sets forth many specific details to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the implementation methods in the specification are only part of the implementation methods of the present invention, not all of the implementation methods.

[0046] As shown in FIG1 , the molten salt heated once-through wet saturated steam generation system provided in an embodiment of the present invention includes an evaporation device 1 , a molten salt conveying device 2 , a preheating device 3 , a softened water conveying device 4 and a dryness adjustment device.

[0047] The evaporation device 1 has a first heat exchange pipe and a second heat exchange pipe. It is understandable that the fluid in the first heat exchange pipe can exchange heat with the fluid in the second heat exchange pipe, wherein the flow direction of the fluid in the first heat exchange pipe can be the same as or opposite to the flow direction of the fluid in the second heat exchange pipe, and these are not restrictive. When the flow direction of the fluid in the first heat exchange pipe is opposite to the flow direction of the fluid in the second heat exchange pipe, the heat exchange effect between the fluids can be further increased. The extension method of the first heat exchange pipe and the second heat exchange pipe is not restricted, and they can be serpentine, etc. In addition, the first heat exchange pipe or the second heat exchange pipe can be a tube side and a shell side, that is, the evaporation device 1 has a pipe for one of the fluids to pass through. At this time, the shell serves as another pipe, so that the other fluid circulates in the shell of the evaporation device 1, thereby realizing heat exchange between the two fluids.

[0048] The molten salt conveying equipment 2 includes a molten salt conveying device connected to the inlet of the first heat exchange pipe and a molten salt recovery device connected to the outlet of the first heat exchange pipe. The molten salt conveying device is used to transport high-temperature molten salt, and the molten salt with a relatively low temperature after heat exchange can flow into the molten salt recovery device. This design allows the molten salt conveying equipment 2 to adopt a direct current heat exchange structure. The molten salt in this application can flow through the shell side to increase the cross-sectional area of ​​the molten salt flow path, thereby preventing molten salt crystallization within the tube side. The molten salt conveying equipment 2 is configured to adjust the temperature and flow rate of the molten salt entering the first heat exchange pipe. The molten salt conveying equipment 2 can adjust the temperature of the molten salt in the first heat exchange pipe to an appropriate range, preventing crystallization caused by excessively low molten salt temperature. In addition, the molten salt conveying equipment 2 can adjust the flow rate of the molten salt conveyed by the molten salt conveying equipment 2 based on the preset dryness of the wet saturated steam conveyed by the steam conveying pipe, so that after heat exchange with the corresponding volume of softened water, the molten salt at that flow rate produces wet saturated steam with a dryness close to the preset dryness of the wet saturated steam, thereby achieving coarse adjustment of the wet saturated steam dryness.

[0049] The preheating device 3 has a first preheating pipe connected to the inlet of the second heat exchange pipe, so that the softened water preheated by the preheating device 3 can enter the second heat exchange pipe. The outlet of the second heat exchange pipe is connected to the steam output pipe 5, so that the fluid (wet saturated steam) after heat exchange by the evaporation device 1 can enter the steam output pipe 5 and be transported to the steam injection well. This design method allows the heat exchange of softened water to adopt an immersed direct current heat exchange structure, which is suitable for the characteristics of oilfield softened water with high silicon content, high chlorine content, and high mineralization, and can also produce wet saturated steam with a certain dryness. The preheating device 3 is configured to preheat the liquid in the first preheating pipe. Among them, the setting method of the preheating device 3 is not limited, and it is only necessary to ensure that the preheating device 3 can preheat the softened water in the first preheating pipe inside it. The preheating device 3 is configured to adjust the temperature of the fluid output through the first preheating pipe. This design enables the preheating device 3 to adjust the temperature of the fluid output through the first preheating pipe to an adaptive range, thereby reducing the temperature difference between the softened water and the molten salt, avoiding the phenomenon of molten salt crystallization caused by the molten salt temperature being too low after heat exchange, and thus avoiding blockage of the first heat exchange pipe, reducing the maintenance frequency of the system, and increasing the service life of the system.

[0050] The softened water delivery device 4 is used to deliver softened water toward the first preheating pipe. The molten salt heated direct current wet saturated steam generating system of this design can use valley electricity or green electricity to heat molten salt energy storage, and then use the molten salt to produce wet saturated steam for oil field production steam injection, thereby increasing the electrification rate of oil field production and reducing carbon dioxide emissions. The softened water delivery device 4 is configured to be able to adjust the flow rate of softened water delivered to the first preheating pipe. Specifically, the softened water delivery device 4 can adjust the flow rate of softened water delivered by the softened water delivery device 4 according to the preset dryness of the wet saturated steam delivered by the steam delivery pipe, so that the softened water of this flow rate and the molten salt of the corresponding capacity are heat-exchanged to obtain wet saturated steam close to the preset dryness of the wet saturated steam, thereby achieving coarse adjustment of the wet saturated steam dryness.

[0051] The dryness adjustment device includes an adjustment element and a dryness detection device 51 disposed on the steam delivery pipeline. The adjustment element is configured to adjust the dryness of the wet saturated steam obtained after heat exchange with the evaporation device 1 based on the dryness information of the wet saturated steam fed back by the dryness detection device 51. After heat exchange between softened water and molten salt in the evaporation device 1, wet saturated steam is obtained that is close to a preset dryness. At this time, the dryness detection device 51 detects the actual dryness of the wet saturated steam. If the dryness of the wet saturated steam deviates from the preset dryness, the adjustment element adjusts the dryness of the wet saturated steam (this can be achieved by adjusting the temperature during the liquid heating process, as described in detail in the following embodiments) to meet the user's requirements.

[0052] Among them, the dryness detection device 51 is a permanent component in this field for detecting the dryness of wet steam. Its structure and working principle are not described in detail here. In this application, the dryness detection device 51 is used to detect the dryness of wet saturated steam output through the steam transmission pipeline.

[0053] In the molten salt heated direct flow wet saturated steam generating system provided by the present invention, softened water first enters the preheating device 3 for preheating, and then flows to the second heat exchange pipe, and the temperature of the preheated softened water entering the second heat exchange pipe can be adjusted by the preheating device 3. At the same time, the temperature of the molten salt entering the first heat exchange pipe can be adjusted by the molten salt conveying device 2, so as to adjust the softened water temperature and the molten salt temperature to the applicable range respectively, thereby avoiding the phenomenon of molten salt crystallization caused by the molten salt temperature being too low after heat exchange, thereby avoiding the blockage of the first heat exchange pipe, reducing the maintenance frequency of the steam generating system and the service life of the steam generating system; in addition, it can The flow rate of molten salt delivery and the flow rate of softened water delivery are adjusted respectively by the molten salt delivery equipment 2 and the softened water delivery equipment 4, thereby achieving coarse adjustment of the dryness of the wet saturated steam obtained after heat exchange and evaporation by the evaporation equipment 1, and then adjusting the dryness of the wet saturated steam according to the dryness information of the wet saturated steam fed back by the dryness detection device 51 through the adjustment component, thereby achieving fine adjustment of the dryness of the wet saturated steam. Through two adjustments, the dryness of the wet saturated steam can be accurately controlled. In addition, the steam generating system of the present application adopts a direct-flow evaporation equipment 1, which can be applied to the characteristics of high silicon content, high chlorine content, and high mineralization of softened water in oil fields to meet the steam injection requirements of oil fields.

[0054] As shown in Figure 1, the molten salt delivery device includes a molten salt storage tank, a molten salt delivery pipeline 21, and a first flow regulating device. The molten salt delivery pipeline 21 is provided with a molten salt pump 22, and the first flow regulating device is used to adjust the operating frequency of the molten salt pump 22. Specifically, the interior of the molten salt storage tank is used to store high-temperature molten salt, wherein the storage therein can be temporary storage, that is, during the molten salt delivery process, it will be accumulated in the molten salt storage tank to ensure the delivery effect of the molten salt. The molten salt storage tank is connected to the molten salt delivery pipeline 21 so that the molten salt in the molten salt storage tank can be delivered to the first heat exchange pipeline through the molten salt pump 22. Among them, the first flow regulating device can adjust the operating frequency of the molten salt pump 22 according to the preset dryness of the wet saturated steam delivered by the steam delivery pipeline, so that the molten salt flow delivered by the molten salt delivery pipeline 21 meets the demand.

[0055] As a feasible implementation mode, the first flow regulating device includes a molten salt flowmeter 23 arranged on the molten salt delivery pipeline 21 and a frequency converter 24 electrically connected to the molten salt pump 22. The frequency converter 24 is configured to adjust the operating frequency of the molten salt pump 22 according to the flow information fed back by the molten salt flowmeter 23.

[0056] With this design, the molten salt flowmeter 23 can monitor the flow rate of the molten salt transported by the molten salt transport pipeline 21 in real time. The resulting molten salt flow rate information is fed back to the control system. The control system then determines the preset operating frequency of the molten salt pump 22 based on the molten salt flow rate information and transmits this preset operating frequency information to the frequency converter 24. After receiving this operating frequency information, the frequency converter 24 adjusts the molten salt pump 22 to the preheating operating frequency to meet the required frequency. The flow rate feedback and adjustment methods are conventional techniques for those skilled in the art and are not described in detail here.

[0057] As shown in Figure 1, the softened water delivery equipment 4 includes a liquid storage tank 41, a liquid delivery pipeline 42, and a second flow control device. The liquid delivery pipeline 42 is provided with a delivery pump 43, and the second flow control device is used to adjust the opening of the delivery pump 43. Specifically, the liquid storage tank 41 is used to store softened water and is connected to the liquid delivery pipeline 42, so that the delivery pump 43 can deliver the liquid in the liquid storage tank 41 to the first preheating pipeline. The second flow control device can adjust the opening of the delivery pump 43 based on the preset dryness of the wet saturated steam delivered by the steam delivery pipeline, so that the liquid flow delivered by the liquid delivery pipeline 42 meets the required flow rate.

[0058] As a feasible implementation, the second flow regulating device includes a liquid flow meter 44 provided on the liquid delivery pipe 42 , and the delivery pump 43 is configured to adjust the opening of the delivery pump 43 according to flow information fed back by the liquid flow meter 44 .

[0059] Under this design, the flow rate of softened water delivered by liquid delivery pipe 42 can be detected in real time by liquid flow meter 44. The obtained softened water flow rate information is fed back to the control system. The control system can then determine the preset operating frequency of delivery pump 43 based on the softened water flow rate information and transmit this preset operating frequency information to delivery pump 43 to adjust the opening of delivery pump 43 so that the flow rate of softened water delivered by liquid delivery pipe 42 meets the required level. The flow rate feedback and adjustment methods are conventional techniques for those skilled in the art and are not described in detail here.

[0060] Further optimized, the softened water delivery device 4 of the present application also includes a liquid supply pipeline for delivering softened water to the liquid storage tank 41. This can then be used to deliver softened water into the liquid storage tank 41, ensuring that the softened water in the liquid storage tank 41 always meets the delivery demand, avoiding the problem of insufficient softened water. Furthermore, the continuous delivery of softened water through the liquid supply pipeline allows the entire system to operate continuously, ensuring operational efficiency.

[0061] Further optimized, the softened water delivery device 4 also includes a liquid level regulating device for adjusting the liquid level height in the liquid storage tank 41. This design can ensure the stability of the softened water level in the liquid storage tank 41, thereby ensuring the stability of the softened water delivery in the liquid storage tank 41, and at the same time ensure that softened water is always stored in the liquid storage tank 41, avoiding system downtime.

[0062] As a feasible embodiment, the liquid level regulating device includes a liquid level gauge disposed within the liquid storage tank 41 and a regulating valve disposed on the liquid supply pipeline. The regulating valve is configured to adjust its opening based on liquid level information fed back by the liquid level gauge. The liquid level gauge is a permanent component for detecting liquid levels, and its structure and operating principle are not described in detail here.

[0063] Under this design, the height of the liquid level in the liquid storage tank 41 can be detected in real time by the liquid level gauge, and the detected liquid level information can be fed back to the control system. The control system sends a corresponding working signal to the regulating valve based on the liquid level information fed back by the liquid level gauge, so that the regulating valve changes the speed at which softened water enters the liquid storage tank 41 by adjusting its own opening, thereby ensuring the stability of the softened water level in the liquid storage tank 41.

[0064] The steam delivery pipeline has a preset steam capacity of 4-6 t / h. The first flow control device adjusts the flow rate of softened water delivered by the softened water delivery device 4 to 6.6-10.9 t / h, and the second flow control device adjusts the flow rate of molten salt delivered by the molten salt delivery device to 21.6-34.2 t / h. By setting the flow rate of softened water delivered by the softened water delivery device 4 and the flow rate of molten salt delivered by the molten salt delivery device, the present application achieves a heat matching relationship between the molten salt flow rate and the liquid flow rate, thereby obtaining wet saturated steam of a preset dryness to meet the steam injection requirements.

[0065] The pressure of the wet saturated steam transported through the steam transport pipeline of the present application has a certain influence on the flow rate of softened water transported by the softened water transport device 4 and the flow rate of molten salt transported by the molten salt transport device, as follows:

[0066] In some embodiments, when the pressure of the wet saturated steam transported through the steam delivery pipeline is 6 MPa, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 6.6-10.4 t / h, and the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 21.6-33.6 t / h.

[0067] Example 1

[0068] The pressure of the wet saturated steam transported through the steam delivery pipeline is 6 MPa. When the preset steam displacement of the steam delivery pipeline is 4 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 6.6-7.6 t / h, preferably 7.1 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 21.6-22.6 t / h, preferably 22.1 t / h.

[0069] Example 2

[0070] The pressure of the wet saturated steam transported through the steam delivery pipeline is 6 MPa. When the preset steam displacement of the steam delivery pipeline is 5 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 8.0-10.0 t / h, preferably 8.5 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 27.1-28.1 t / h, preferably 27.6 t / h.

[0071] Example 3

[0072] The pressure of the wet saturated steam transported through the steam delivery pipeline is 6 MPa. When the preset steam displacement of the steam delivery pipeline is 6 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 9.4-10.4 t / h, preferably 9.9 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 32.6-33.6 t / h, preferably 33.1 t / h.

[0073] In other embodiments, when the pressure of the wet saturated steam transported through the steam delivery pipeline is 7 MPa, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 6.7-10.7 t / h, and the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 21.9-33.9 t / h.

[0074] Example 1

[0075] The pressure of the wet saturated steam transported through the steam delivery pipeline is 7 MPa. When the preset steam displacement of the steam delivery pipeline is 4 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 6.7-7.8 t / h, preferably 7.2 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 21.9-22.9 t / h, preferably 22.4 t / h.

[0076] Example 2

[0077] The pressure of the wet saturated steam transported through the steam delivery pipeline is 7 MPa. When the preset steam displacement of the steam delivery pipeline is 5 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 8.2-10.2 t / h, preferably 8.7 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 27.4-28.4 t / h, preferably 27.7 t / h.

[0078] Example 3

[0079] The pressure of the wet saturated steam transported through the steam delivery pipeline is 7 MPa. When the preset steam displacement of the steam delivery pipeline is 6 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 9.7-10.7 t / h, preferably 10.2 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 32.9-33.9 t / h, preferably 33.4 t / h.

[0080] In other embodiments, when the pressure of the wet saturated steam transported through the steam delivery pipeline is 8 MPa, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 6.9-10.9 t / h, and the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 22.2-34.2 t / h.

[0081] Example 1

[0082] The pressure of the wet saturated steam transported through the steam delivery pipeline is 8 MPa. When the preset steam displacement of the steam delivery pipeline is 4 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 6.9-8.0 t / h, preferably 7.4 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 22.2-23.2 t / h, preferably 22.7 t / h.

[0083] Example 2

[0084] The pressure of the wet saturated steam transported through the steam delivery pipeline is 8 MPa. When the preset steam displacement of the steam delivery pipeline is 5 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 8.4-10.4 t / h, preferably 8.9 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 27.7-28.7 t / h, preferably 28.2 t / h.

[0085] Example 3

[0086] The pressure of the wet saturated steam transported through the steam delivery pipeline is 8 MPa. When the preset steam displacement of the steam delivery pipeline is 6 t / h, the first flow regulating device adjusts the flow rate of softened water transported by the softened water delivery equipment 4 to 9.9-10.9 t / h, preferably 10.4 t / h; the second flow regulating device adjusts the flow rate of molten salt transported by the molten salt delivery device to 33.2-34.2 t / h, preferably 33.7 t / h.

[0087] The preheating device 3 also has a second preheating pipe. It is understandable that the fluid in the first preheating pipe can exchange heat with the fluid in the second preheating pipe, wherein the flow direction of the fluid in the first preheating pipe can be the same as or opposite to the flow direction of the fluid in the second preheating pipe. These are not restrictive. When the flow direction of the fluid in the first preheating pipe is opposite to the flow direction of the fluid in the second preheating pipe, the heat exchange effect between the fluids can be further increased. Among them, the extension method of the first preheating pipe and the second preheating pipe is not restricted, and they can be serpentine, etc. The inlet of the second preheating pipe is connected to the steam output pipe 5. Under this design method, the excess steam transported by the steam output pipe 5 is diverted to the preheating device 3 to preheat the softened water in the preheating device 3, avoiding heat waste and reducing steam transportation costs. The outlet of the second preheating pipe is connected to the softened water transportation device 4. Under this design, the excess steam transported by the steam output pipe 5 is diverted to the preheating device 3 to preheat the softened water in the preheating device 3, and the preheated condensate flows back to the softened water transporting device 4, reducing the setting of additional collection equipment, rationally utilizing resources, and avoiding heat waste.

[0088] The preheating device 3 also includes a condensate delivery pipe 31 and a condensate regulating valve 32 disposed on the condensate delivery pipe 31. The outlet of the second preheating pipe is connected to the softened water delivery device 4 via the condensate delivery pipe 31, and the temperature of the fluid output from the first preheating pipe can be adjusted by adjusting the opening of the condensate regulating valve 32. Under this design, the condensate obtained after heat exchange and cooling of the wet saturated steam can be delivered to the softened water delivery device 4 via the condensate delivery pipe 31. The condensate regulating valve can adjust the residence time of the wet saturated steam in the second preheating pipe by adjusting its own opening, thereby adjusting the heat exchange efficiency between the wet saturated steam in the second preheating pipe and the softened water in the first preheating pipe, thereby changing the temperature of the softened water output from the first preheating pipe, so that the first preheating pipe can deliver softened water that meets demand.

[0089] The preheating device 3 also includes a first temperature detection device for detecting the temperature of the fluid flowing out of the outlet of the first preheating pipe. This design allows the first temperature detection device to monitor the temperature of the softened water flowing out of the first preheating pipe in real time. When the temperature of the softened water flowing out of the first preheating pipe is detected to be lower than a preset temperature, the operator can adjust the condensate regulating valve to ensure that the temperature of the softened water flowing out of the first preheating pipe meets the preset requirement. The first temperature detection device can be a temperature sensor to detect the temperature of the softened water flowing out of the first preheating pipe.

[0090] In a further optimization, the first temperature detection device is electrically connected to the condensate regulating valve, which is configured to adjust its opening based on temperature information fed back by the first temperature detection device. This design allows for automatic adjustment of the condensate regulating valve's opening, thereby enabling automated control of the temperature of the softened water flowing out of the first preheating pipe.

[0091] The steam output pipe 5 is connected to the inlet of the second preheating pipe through the return pipe 6, and the return pipe 6 is connected to a steam conveying device 61. Specifically, the inlet of the return pipe 6 is connected to the steam output pipe 5, and the outlet of the return pipe 6 is connected to the inlet of the second preheating pipe. Under this design, the wet saturated steam in the steam output pipe 5 is diverted to the second preheating pipe through the return pipe 6, wherein the return pipe 6 can have a certain length so that the wet saturated steam can be cooled when it refluxes, thereby avoiding scaling caused by the excessive temperature difference between the refluxed wet saturated steam and the softened water. The length of the return pipe 6 can be designed according to actual needs to ensure that the wet saturated steam can be reduced to a preset temperature. In addition, the flow rate of the wet saturated steam reflux can be controlled by setting a valve on the return pipe 6 to ensure that the amount of wet saturated steam input into the steam injection wellhead meets the demand.

[0092] In addition, the steam delivery device 61 can be used to provide steam of a certain temperature to the second preheating pipe when the system is not fully operational (the steam output pipe 5 does not produce wet saturated steam), so that the softened water in the preheating device 3 can be preheated by steam introduced from the outside.

[0093] As shown in Figure 1, the evaporation apparatus 1 includes an evaporator 11. The first heat exchange pipeline includes a first evaporation pipeline disposed within the evaporator 11. The inlet of the first evaporation pipeline is connected to a molten salt delivery device, and the outlet of the first evaporation pipeline is connected to a molten salt recovery device. The first evaporation pipeline can be connected to the molten salt delivery device directly or via other pipelines. The first evaporation pipeline can be connected to the molten salt recovery device directly or via other pipelines, and the design can be customized based on actual needs.

[0094] The second heat exchange pipeline includes a second evaporation pipeline disposed within the evaporator 11. The inlet of the second evaporation pipeline is connected to the outlet of the first preheating pipeline, and the outlet of the second evaporation pipeline is connected to the steam output pipeline 5. The second evaporation pipeline can be connected to the outlet of the first preheating pipeline directly or through other pipelines. The outlet of the second evaporation pipeline can be connected to the steam output pipeline 5 directly or through other pipelines. These are not restrictive and can be designed according to actual needs. The molten salt in the first evaporation pipeline can exchange heat with the softened water in the second evaporation pipeline to heat the softened water into wet saturated steam. The extension method of the first and second evaporation pipelines is not limited and can be designed according to actual needs. In addition, the first evaporation pipeline can be formed by the inner cavity of the evaporator 11, that is, the molten salt flows through the shell side and the softened water flows through the tube side to prevent the molten salt from crystallizing within the tube side.

[0095] Further optimized, the evaporator 11 is configured so that the fluid flow direction in the first evaporation pipe is opposite to the fluid flow direction in the second evaporation pipe. This design allows the fluid in the first evaporation pipe to circulate with the fluid in the second evaporation pipe, achieving forced heat exchange and further increasing the heat exchange efficiency between the molten salt and softened water in the evaporator 11.

[0096] As shown in FIG1 , the evaporation device 1 further includes a heater 12, and the first heat exchange pipe further includes a first heating pipe disposed within the heater 12. The inlet of the first heating pipe is connected to the outlet of the first evaporation pipe, and the outlet of the first heating pipe is connected to the molten salt recovery device. The outlet of the first heating pipe can be directly connected to the molten salt recovery device, or the outlet of the first heating pipe can be connected to the molten salt recovery device via other pipes. The inlet of the first heating pipe can also be directly connected to the outlet of the first evaporation pipe, or the inlet of the first heating pipe can be connected to the outlet of the first evaporation pipe via other pipes, and these are not restrictive.

[0097] The second heat exchange pipe also includes a second heating pipe arranged inside the heater 12, the inlet of the second heating pipe is connected to the outlet of the first preheating pipe, and the outlet of the second heating pipe is connected to the inlet of the second evaporation pipe. The inlet of the second heating pipe here can be directly connected to the outlet of the first preheating pipe, and the inlet of the second heating pipe can also be connected to the outlet of the first preheating pipe through other pipes. The outlet of the second heating pipe can be directly connected to the inlet of the second evaporation pipe, and the outlet of the second heating pipe can also be connected to the inlet of the second evaporation pipe through other pipes. These are not restrictive. Among them, the extension method of the first heating pipe and the second heating pipe is not restricted and can be designed according to actual needs. In addition, the first heating pipe can be formed by the inner cavity of the heater 12, that is, the molten salt is allowed to flow through the shell side and the softened water is allowed to flow through the tube side to avoid crystallization of the molten salt in the tube side.

[0098] Further optimized, heater 12 is configured such that the fluid flow direction in the first heating conduit is opposite to the fluid flow direction in the second heating conduit. This design allows for convection between the fluid in the first heating conduit and the fluid in the second heating conduit to achieve forced heat exchange, further increasing the heat exchange efficiency between the molten salt and softened water in heater 12.

[0099] In this design, the molten salt, after undergoing heat exchange and cooling in the evaporator 11, then enters the first heating pipe. At this point, the molten salt's temperature drops, allowing the relatively low-temperature molten salt to heat the softened water entering the second heating pipe. The heated softened water then enters the second evaporation pipe for evaporation, forming wet saturated steam. This evaporation device 1 implements a heat exchange method that heats the softened water before evaporating it, facilitating temperature control of the liquid after heat exchange, thereby facilitating control of the dryness of the wet saturated steam and regulating the temperature of the molten salt.

[0100] The molten salt conveying equipment 2 also includes a molten salt bypass line 25, the inlet of the molten salt bypass line 25 is connected to the molten salt conveying device, the outlet of the molten salt bypass line 25 is connected to the outlet of the first evaporation pipe, and the molten salt bypass line 25 is provided with a first regulating valve for regulating the flow rate of the molten salt. Among them, the inlet of the molten salt bypass line 25 can be directly connected to the molten salt conveying pipe 21, and the inlet of the molten salt bypass line 25 can also be connected to the molten salt conveying pipe 21 through other pipelines. The outlet of the molten salt bypass line 25 can be directly connected to the outlet of the first evaporation pipe, and the outlet of the molten salt bypass line 25 can also be connected to the outlet of the first evaporation pipe through other pipelines. These are not restrictive and can be designed according to actual needs. The first regulating valve can adjust the on and off of the molten salt bypass line 25, and can also adjust the flow rate of the molten salt flowing through the molten salt bypass line 25 by the size of the opening of the first regulating valve itself.

[0101] Under this design, the first regulating valve can be opened so that part of the molten salt does not pass through the evaporator 11, but is mixed with the molten salt after heat exchange and cooling in the evaporator 11 and then enters the heater 12 together, so as to increase the temperature of the molten salt entering the heater 12, thereby preventing the temperature of the molten salt from dropping below the crystallization temperature after heat exchange and cooling with softened water, thereby avoiding the phenomenon of molten salt crystallization.

[0102] The molten salt conveying equipment 2 also includes a second temperature detection device for detecting the temperature of the molten salt flowing out of the first evaporation pipe. This design method can monitor the temperature of the molten salt flowing out of the first evaporation pipe in real time through the second temperature detection device, and then when it is detected that the temperature of the molten salt flowing out of the first evaporation pipe is lower than the preset temperature, the staff can adjust the opening of the first regulating valve so that the temperature of the molten salt flowing out of the first evaporation pipe meets the preset requirements. Among them, the second temperature detection device can be a temperature sensor, which can detect the temperature of the molten salt flowing out of the first evaporation pipe through the temperature sensor. The temperature sensor can be specifically set on the outflow pipe of the first evaporation pipe. Of course,

[0103] In a further optimization, the first regulating valve is electrically connected to the second temperature detection device, and is configured to adjust its opening based on temperature information fed back by the second temperature detection device. This design allows for automatic adjustment of the opening of the first regulating valve, thereby enabling automated control of the temperature of the molten salt flowing out of the first evaporation pipe.

[0104] The regulating component includes a softened water bypass pipeline 7 and a second regulating valve 71 arranged on the softened water bypass pipeline 7. The inlet of the softened water bypass pipeline 7 is connected to the outlet of the first preheating pipeline, and the outlet of the softened water bypass pipeline 7 is connected to the inlet of the second evaporation pipeline. The second regulating valve 71 is configured to be able to adjust the opening of the second regulating valve 71 according to the dryness information of the wet saturated steam fed back by the dryness detection device 51.

[0105] Under this design, part of the fluid flowing to the heater 12 through the preheating device 3 can be diverted through the bypass line. This part of the fluid will bypass the heater 12 and mix with the part of the fluid heated by the heater 12 before entering the evaporator 11, thereby changing the temperature of the fluid entering the evaporator 11 to adjust the dryness of the wet saturated steam after evaporation in the evaporator 11. When the dryness detection device 51 detects a deviation between the dryness of the wet saturated steam and the preset dryness, the deviation information can be transmitted to the second regulating valve 71. The second regulating valve 71 changes its opening to adjust the flow rate of the fluid passing through the bypass line, thereby changing the temperature of the fluid entering the evaporator 11, so that the dryness of the wet saturated steam obtained through heat exchange in the evaporator 11 is consistent with the preset dryness, thereby achieving precise adjustment of the dryness of the wet saturated steam.

[0106] Further optimized, the second regulating valve 71 is a one-way valve to allow fluid to flow from the first preheating pipe to the second evaporation pipe. The one-way valve configuration prevents fluid in the evaporator 11 from flowing back into the preheater, ensuring the safety of the entire device and the stability of heat exchange.

[0107] The outlet of the first preheating pipe is also connected to a shunt pipe equipped with a third regulating valve for regulating the flow rate of softened water. The shunt pipe is used to discharge softened water that has not been heated to the preheating temperature. Specifically, when the system is initially operational, the temperature of the softened water transported through the first preheating pipe does not meet the preset temperature requirement. To prevent the softened water, which is too cold, from entering the evaporation device 1, the softened water that has not reached the preset temperature can be discharged from the shunt pipe. When the temperature of the softened water transported through the first preheating pipe reaches the preset temperature, the third regulating valve closes, allowing the softened water to flow into the evaporation device 1.

[0108] It is understood that a shutoff valve should be provided at the inlet of the evaporation apparatus 1. In conjunction with the above-described embodiment, the molten salt delivery apparatus 2 further includes a second temperature detection device for detecting the temperature of the softened water flowing out of the outlet of the first preheating pipe. When the second temperature detection device detects that the temperature of the softened water flowing out of the first preheating pipe is below a preset temperature, the shutoff valve closes to prevent the low-temperature softened water from entering the evaporation apparatus 1. When the second temperature detection device detects that the temperature of the softened water flowing out of the first preheating pipe reaches a preset temperature, the shutoff valve opens to allow the softened water at the preset temperature to enter the evaporation apparatus 1 and participate in heat exchange.

[0109] Accordingly, when the second temperature detection device detects that the temperature of the softened water flowing out of the first preheating pipe is lower than a preset temperature, the third regulating valve opens, allowing the low-temperature softened water to flow out through the diversion pipe, thereby preventing the low-temperature softened water from entering the evaporation device 1. When the second temperature detection device detects that the temperature of the softened water flowing out of the first preheating pipe reaches the preset temperature, the third regulating valve closes, ensuring that all the softened water reaching the preset temperature can enter the evaporation device 1 and participate in the heat exchange.

[0110] The molten salt heated once-through wet saturated steam generating system further comprises a pressure relief device, which is configured to release the fluid and superheated steam in the evaporation device 1 when the softened water delivery device 4 stops working.

[0111] Under this design, when the softened water delivery equipment 4 stops working, the fluid and superheated steam in the evaporation equipment 1 can be released through the pressure relief equipment to prevent the superheated wet saturated steam from flowing into the oil field steam injection system, eliminating safety hazards and ensuring the safe operation of the steam injection system. In addition, the superheated steam can be opened at low pressure to avoid safety hazards and noise pollution caused by high-pressure exhaust.

[0112] As a feasible embodiment, the pressure relief device includes a pressure relief pipe 8 connected to the outlet of the first preheating pipe and a first pressure relief valve 81 disposed on pressure relief pipe 8. First pressure relief valve 81 is configured to open when the softened water delivery device 4 stops delivering softened water. Furthermore, evaporation device 1 is configured so that when first pressure relief valve 81 opens, the fluid in the second heat exchange pipe can flow into pressure relief pipe 8. Under this design, when the system is shut down and the softened water delivery device 4 stops operating, first pressure relief valve 81 opens upon receiving a signal from the softened water delivery device 4 to stop operating, allowing the liquid in the second heat exchange pipe to flow into pressure relief pipe 8 and then to a designated location, thereby reducing system pressure.

[0113] Further optimized, the outlet of the pressure relief pipe 8 is connected to a discharge expander 82. This design allows the liquid in the second heat exchange pipe of the evaporation apparatus 1 to flow into the discharge expander 82, thereby achieving system pressure relief. The discharge expander 82 is a device that can be installed at the outlet of the pressure relief pipe 8 to achieve continuous liquid discharge, pressure reduction, and volume expansion. This design is conventional in the art, and therefore, its specific structure and operating principle are not described in detail here.

[0114] The pressure relief device includes an exhaust pipe 9 connected to the steam output pipe 5 and a second pressure relief valve 91 disposed on the exhaust pipe 9. The second pressure relief valve 91 is configured to open when the pressure in the steam output pipe 5 falls below a preset pressure. Under this design, when the system shuts down, the first pressure relief valve 81 opens, allowing the liquid in the second heat exchange pipe to flow into the pressure relief pipe 8. This reduces the pressure in the system, and in turn, the pressure in the steam output pipe 5. Once the pressure in the steam output pipe 5 falls below the preset pressure, the second pressure relief valve 91 opens. At this point, the exhaust pipe 9 is open, allowing the superheated steam in the evaporation device 1 to flow out through the exhaust pipe 9, thereby preventing the superheated steam from entering the steam injection well.

[0115] The steam output pipe 5 is provided with a pressure detection device 52 for detecting the pressure of the circulating wet saturated steam. The pressure detection device 52 is electrically connected to the second pressure relief valve 91. This design allows the pressure detection device 52 to monitor the pressure of the wet saturated steam delivered through the steam output pipe 5 in real time, allowing staff to intuitively understand the delivery status of the wet saturated steam.

[0116] The pressure detection device 52 may be a pressure gauge, and the pressure gauge should be suitable for high temperature environments to ensure the service life of the pressure gauge itself.

[0117] In addition, the pressure detection device 52 can also be a pressure transmitter. Among them, the pressure transmitter mainly consists of three parts: a pressure element sensor (also called a pressure sensor), a measuring circuit, and a process connection. It can convert the physical pressure parameters of gas, liquid, etc. sensed by the pressure element sensor into a standard electrical signal (such as 4-20mADC, etc.) to supply secondary instruments such as indicator alarms, recorders, and regulators for measurement, indication, and process adjustment. In this application, the pressure transmitter is used to detect the pressure of the wet saturated steam in the steam output pipe 5, and the pressure transmitter is electrically connected to the second pressure relief valve 91 so that the pressure in the steam output pipe 5 is reduced to a certain set value, and the pressure transmitter signal interlock opens the second pressure relief valve 91.

[0118] When the pressure detection device 52 detects that the pressure of the wet saturated steam is lower than a preset pressure, the second pressure relief valve 91 opens. Specifically, the pressure detection device 52 is electrically connected to the second pressure relief valve 91 to achieve a linkage between the pressure detection device 52 and the second pressure relief valve 91. When the pressure detection device 52 detects that the pressure of the wet saturated steam is lower than a preset pressure, the second pressure relief valve 91 opens.

[0119] Under this design, the second pressure relief valve 91 is normally closed. When the system shuts down and the softened water delivery equipment 4 ceases operation, the first pressure relief valve 81 opens, allowing the pressure relief pipe 8 to flow. At this point, the liquid in the second heat exchange pipe of the evaporation equipment 1 flows out through the pressure relief pipe 8, instantly releasing the pressure within the molten salt heated steam generation system. At this point, the pressure drop within the molten salt heated steam generation system causes the pressure in the steam output pipe 5 to drop. When the pressure detection device 52 detects that the pressure of the wet saturated steam is lower than the preset pressure, the second pressure relief valve 91 opens, allowing the superheated steam in the evaporation equipment 1 to flow out through the exhaust pipe 9, preventing the superheated steam from entering the oilfield steam injection system and ensuring the safe operation of the steam injection system.

[0120] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0121] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments described herein, but is to be construed in the widest possible manner consistent with the principles and novel features disclosed herein.

Claims

1. A molten salt heated once-through wet saturated steam generating system, characterized in that: include: An evaporation device (1) comprises a first heat exchange pipe and a second heat exchange pipe; A molten salt conveying device (2), comprising a molten salt conveying device connected to the inlet of the first heat exchange pipe and a molten salt recovery device connected to the outlet of the first heat exchange pipe, wherein the molten salt conveying device (2) is configured to be able to adjust the temperature and flow rate of the molten salt entering the first heat exchange pipe; A preheating device (3) comprising a first preheating pipe connected to the inlet of the second heat exchange pipe, the outlet of the second heat exchange pipe being connected to a steam output pipe (5), the preheating device (3) being configured to preheat the liquid in the first preheating pipe, and the preheating device (3) being configured to adjust the temperature of the fluid output through the first preheating pipe; A softened water delivery device (4) is used to deliver softened water into the first preheating pipe, and the softened water delivery device (4) is configured to be able to adjust the flow rate of the softened water delivered to the first preheating pipe; A dryness adjustment device comprises an adjustment component and a dryness detection device (51) arranged on the steam delivery pipeline, wherein the adjustment component is configured to adjust the dryness of the wet saturated steam obtained after the fluid passes through the evaporation device (1) for heat exchange according to the dryness information of the wet saturated steam fed back by the dryness detection device (51).

2. The molten salt heated once-through wet saturated steam generating system according to claim 1, characterized in that: The molten salt conveying device comprises a molten salt storage tank, a molten salt conveying pipeline (21) and a first flow regulating device, wherein a molten salt pump (22) is provided on the molten salt conveying pipeline (21), and the first flow regulating device is used to regulate the operating frequency of the molten salt pump (22).

3. The molten salt heated once-through wet saturated steam generating system according to claim 2, characterized in that: The first flow regulating device comprises a molten salt flow meter (23) arranged on the molten salt delivery pipeline (21) and a frequency converter (24) electrically connected to the molten salt pump (22), wherein the frequency converter (24) is configured to adjust the operating frequency of the molten salt pump (22) according to flow information fed back by the molten salt flow meter (23).

4. The molten salt heated once-through wet saturated steam generation system according to claim 1, characterized in that: The softened water delivery equipment (4) comprises a liquid storage tank (41), a liquid delivery pipeline (42) and a second flow regulating device, wherein a delivery pump (43) is provided on the liquid delivery pipeline (42), and the second flow regulating device is used to adjust the opening of the delivery pump (43).

5. The molten salt heated once-through wet saturated steam generating system according to claim 4, characterized in that: The second flow regulating device comprises a liquid flow meter (44) arranged on the liquid delivery pipeline (42), and the delivery pump (43) is configured to be able to adjust the opening of the delivery pump (43) according to flow information fed back by the liquid flow meter (44).

6. The molten salt heated once-through wet saturated steam generation system according to claim 1, characterized in that: The preheating device (3) also has a second preheating pipeline, the inlet of the second preheating pipeline is connected to the steam output pipeline (5), and the outlet of the second preheating pipeline is connected to the softened water delivery device (4).

7. The molten salt heated once-through wet saturated steam generating system according to claim 6, characterized in that: The preheating device (3) further comprises a condensate delivery pipeline (31) and a condensate regulating valve (32) arranged on the condensate delivery pipeline (31); the outlet of the second preheating pipeline is connected to the softened water delivery device (4) via the condensate delivery pipeline (31), and is configured as follows: The temperature of the fluid output from the first preheating pipeline can be adjusted by adjusting the opening of the condensed water regulating valve (32).

8. The molten salt heated once-through wet saturated steam generation system according to claim 7, characterized in that: The preheating device (3) also includes a first temperature detection device for detecting the temperature of the fluid flowing out through the outlet of the first preheating pipe, the first temperature detection device is electrically connected to the condensate regulating valve, and the condensate regulating valve is configured to be able to adjust the opening of the condensate regulating valve according to the temperature information fed back by the first temperature detection device.

9. The molten salt heated once-through wet saturated steam generating system according to claim 6, characterized in that: The steam output pipeline (5) is connected to the inlet of the second preheating pipeline via a return pipeline (6), and the return pipeline (6) is connected to a steam conveying device (61).

10. The molten salt heated once-through wet saturated steam generation system according to claim 1, characterized in that: The evaporation device (1) comprises an evaporator (11), The first heat exchange pipeline comprises a first evaporation pipeline arranged inside the evaporator (11), the inlet of the first evaporation pipeline is connected to the molten salt conveying device, and the outlet of the first evaporation pipeline is connected to the molten salt recovery device; The second heat exchange pipeline comprises a second evaporation pipeline arranged in the evaporator (11), the inlet of the second evaporation pipeline is connected to the outlet of the first preheating pipeline, and the outlet of the second evaporation pipeline is connected to the steam output pipeline (5).

11. The molten salt heated once-through wet saturated steam generation system according to claim 10, characterized in that: The evaporation device (1) further comprises a heater (12), The first heat exchange pipeline also includes a first heating pipeline arranged inside the heater (12), the inlet of the first heating pipeline is connected to the outlet of the first evaporation pipeline, and the outlet of the first heating pipeline is connected to the molten salt recovery device; The second heat exchange pipe also includes a second heating pipe arranged inside the heater (12), the inlet of the second heating pipe is connected to the outlet of the first preheating pipe, and the outlet of the second heating pipe is connected to the inlet of the second evaporation pipe.

12. The molten salt heated once-through wet saturated steam generation system according to claim 11, characterized in that: The molten salt conveying equipment (2) further comprises a molten salt bypass pipeline (25), the inlet of the molten salt bypass pipeline (25) being connected to the molten salt conveying device, the outlet of the molten salt bypass pipeline (25) being connected to the outlet of the first evaporation pipeline, and the molten salt bypass pipeline (25) being provided with a first regulating valve for regulating the molten salt flow rate.

13. The molten salt heated once-through wet saturated steam generation system according to claim 12, characterized in that: The molten salt conveying equipment (2) further comprises a second temperature detection device for detecting the temperature of the molten salt flowing out of the first evaporation pipeline, the first regulating valve is electrically connected to the second temperature detection device, and the first regulating valve is configured to be able to adjust the opening of the first regulating valve according to the temperature information fed back by the second temperature detection device.

14. The molten salt heated once-through wet saturated steam generation system according to claim 11, characterized in that: The regulating component comprises a softened water bypass pipeline (7) and a second regulating valve (71) arranged on the softened water bypass pipeline (7); the inlet of the softened water bypass pipeline (7) is connected to the outlet of the first preheating pipeline; the outlet of the softened water bypass pipeline (7) is connected to the inlet of the second evaporation pipeline; the second regulating valve (71) is arranged to be able to adjust the opening of the second regulating valve (71) according to the dryness information of the wet saturated steam fed back by the dryness detection device (51).

15. The molten salt heated once-through wet saturated steam generation system according to claim 1, characterized in that: The outlet of the first preheating pipeline is also connected to a diversion pipeline, and the diversion pipeline is provided with a third regulating valve for adjusting the flow rate of softened water.

16. The molten salt heated once-through wet saturated steam generation system according to any one of claims 1 to 15, characterized in that: The molten salt heated direct flow wet saturated steam generating system further comprises a pressure relief device, wherein the pressure relief device is configured to release the fluid and superheated steam in the evaporation device (1) when the softened water delivery device (4) stops working.

17. The molten salt heated once-through wet saturated steam generation system according to claim 16, characterized in that: The pressure relief device comprises a pressure relief pipe (8) connected to the outlet of the first preheating pipe and a first pressure relief valve (81) arranged on the pressure relief pipe (8), wherein the first pressure relief valve (81) is arranged to open when the softened water delivery device (4) stops delivering softened water, and the evaporation device (1) is arranged so that when the first pressure relief valve (81) is opened, the fluid in the second heat exchange pipe can flow to the pressure relief pipe (8).

18. The molten salt heated once-through wet saturated steam generation system according to claim 17, characterized in that: The outlet of the pressure relief pipe (8) is connected to a discharge expansion tank (82).

19. The molten salt heated once-through wet saturated steam generation system according to claim 16, characterized in that: The pressure relief device comprises an exhaust pipe (9) connected to the steam output pipe (5) and a second pressure relief valve (91) arranged on the exhaust pipe (9), wherein the second pressure relief valve (91) is arranged to open when the pressure in the steam output pipe (5) is lower than a preset pressure.

20. The molten salt heated once-through wet saturated steam generation system according to claim 19, characterized in that: The steam output pipeline (5) is provided with a pressure detection device (52) for detecting the pressure of the circulating wet saturated steam. The pressure detection device (52) is electrically connected to the second pressure relief valve (91) and is configured as follows: When the pressure detection device (52) detects that the pressure of the wet saturated steam is lower than the preset pressure, the second pressure relief valve (91) opens.

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