High-temperature sulfur melting heat storage and hot water supply system for oil field

Abstract

The utility model provides a high-temperature molten sulfur heat storage hot water supply system for oil field, which comprises a molten sulfur heat storage tank, a water inlet pipeline and a water outlet pipeline, in the water flowing direction, the water inlet pipeline comprises a first water inlet pipe, a water pump and a second water inlet pipe which are connected in sequence, and the water outlet pipeline comprises a first water outlet pipe, a buffer tank and a second water outlet pipe which are connected in sequence; the molten sulfur heat storage tank is provided with a molten sulfur storage cavity, is used for accommodating and storing molten sulfur and comprises an electric heater; a heat exchange pipe is arranged in the molten sulfur heat storage tank, an inlet of the heat exchange pipe is connected with an outlet of the second water inlet pipe, and an outlet of the heat exchange pipe is connected with an inlet of the first water outlet pipe; according to the utility model, the conventional heat supply system in the current oil field is improved, peak load shifting is carried out on electric energy by utilizing high-temperature molten sulfur heat storage, peak load shifting of the electric energy can be effectively carried out, and the power utilization cost is also favorably reduced.

Description

Technical Field

[0001] The utility model relates to the field of oil field oil extraction and transportation heating, in particular to a high-temperature molten sulfur heat storage and hot water supply system for oil fields. Background Art

[0002] Oilfield production and transportation operations often require heating pipelines with 80°C hot water, raising the crude oil in the pipeline from 25°C to approximately 50°C. After heating, the return water temperature is approximately 40°C. Traditionally, this method uses natural gas / gas as fuel, burning it in a heating furnace to directly generate hot water. These furnaces range in power from 100kW to 3000kW. While not large in power, they are numerous. One single CNPC production site alone requires tens of thousands of these furnaces.

[0003] Some oil production sites are considering replacing traditional fuel-fired furnaces with electric heating. However, the current national power supply is relatively tight, and grid power often exhibits peak and valley characteristics. Existing conventional electric heating furnaces often have difficulty regulating peak and valley power.

[0004] Therefore, it is necessary to improve the current conventional heating system for oil production and transportation in order to achieve peak shaving and valley filling of electricity. Utility Model Content

[0005] In view of this, the utility model aims to propose a high-temperature molten sulfur heat storage and hot water supply system for oil fields, to improve the conventional heating system in the prior art, and to optimize and effectively utilize the electricity by storing heat in high-temperature molten sulfur to smooth the peak flow of electricity, so as to solve the problems of high carbon emissions, difficulty in peak and valley electricity regulation, and high electricity costs in conventional heating systems.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0007] A high-temperature molten sulfur heat storage and hot water supply system for oil fields includes a molten sulfur heat storage tank, a water inlet pipeline, and a water outlet pipeline. In the direction of water flow, the water inlet pipeline includes a first water inlet pipe, a water pump, and a second water inlet pipe connected in sequence, and the water outlet pipeline includes a first water outlet pipe, a buffer tank, and a second water outlet pipe connected in sequence; the molten sulfur heat storage tank has a molten sulfur storage chamber for accommodating and storing molten sulfur, and the molten sulfur heat storage tank includes an electric heater; a heat exchange tube is provided in the molten sulfur heat storage tank, the inlet of the heat exchange tube is connected to the outlet of the second water inlet pipe, and the outlet of the heat exchange tube is connected to the inlet of the first water outlet pipe.

[0008] Furthermore, the system includes a first bridge circuit, an inlet of the first bridge circuit is connected to the second water inlet pipe, an outlet of the first bridge circuit is connected to the first water outlet pipe, and a water heater is provided in the first bridge circuit.

[0009] Furthermore, a first valve is provided in the second water inlet pipe, and a second valve is provided in the first water outlet pipe; in the flow direction of water in the second water inlet pipe, the inlet of the first bridge circuit is located upstream of the first valve, and in the flow direction of water in the first water outlet pipe, the outlet of the first bridge circuit is located downstream of the second valve.

[0010] Furthermore, the system includes a water heater, which is arranged in the second water outlet pipe.

[0011] Furthermore, the system includes a second bridge circuit, the inlet of the second bridge circuit is connected to the second water inlet pipe, the outlet of the second bridge circuit is connected to the first water outlet pipe, and a second electrically controlled valve is provided in the second bridge circuit.

[0012] Furthermore, a temperature sensor is provided in the first water outlet pipe, and in the flow direction of water in the first water outlet pipe, the temperature sensor is located downstream of the outlet of the second bridge circuit.

[0013] Furthermore, the system includes a third bridge circuit, the inlet of the third bridge circuit is connected to the first water outlet pipe, the outlet of the third bridge circuit is connected to the first water inlet pipe, and a third electrically controlled valve is provided in the third bridge circuit.

[0014] Furthermore, a first electrically controlled valve is provided in the first water outlet pipe. In the flow direction of water in the first water outlet pipe, the first electrically controlled valve is located downstream of the inlet of the third bridge circuit.

[0015] Furthermore, the system includes a first bridge circuit, a second bridge circuit, and a third bridge circuit, a water heater is provided in the first bridge circuit, a second electrically controlled valve is provided in the second bridge circuit, and a third electrically controlled valve is provided in the third bridge circuit; the outlet of the third bridge circuit is connected to the first water inlet pipe; along the flow direction of water in the second water inlet pipe, the inlet of the first bridge circuit, the first valve, and the inlet of the second bridge circuit are provided in sequence; along the flow direction of water in the first water outlet pipe, the outlet of the second bridge circuit, the inlet of the third bridge circuit, the first electrically controlled valve, and the outlet of the first bridge circuit are provided in sequence.

[0016] Furthermore, a temperature sensor is provided in the first water outlet pipe, and the temperature sensor is located between the outlet of the second bridge and the inlet of the third bridge.

[0017] Compared with the existing technology, the high-temperature molten sulfur heat storage and hot water supply system for oil fields described in this utility model has the following advantages:

[0018] The utility model discloses a high-temperature molten sulfur heat storage and hot water supply system for oil fields. By improving the conventional heating system in the current oil fields, the high-temperature molten sulfur heat storage is used to smooth the peak and fill the valley of electric energy while providing hot water to the oil pipeline, thereby avoiding the use of conventional boilers. The system can fully utilize the valley power period for heat storage and energy supply, and can only use the high-temperature molten sulfur heat storage for heating during the peak power period. The system can effectively smooth the peak and fill the valley of electric energy, and is also conducive to reducing electricity costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 This is a schematic diagram of a high-temperature molten sulfur heat storage and hot water supply system for oil fields according to an embodiment of the present utility model;

[0021] Figure 2 This is another schematic diagram of the high-temperature molten sulfur heat storage and hot water supply system for oil fields according to an embodiment of the present utility model;

[0022] Figure 3 For the embodiment of the present utility model Figure 2 Schematic diagram of the sulfur melting module on the foundation;

[0023] Figure 4 For the embodiment of the utility model Figure 2 Schematic diagram of the exhaust gas treatment module based on the medium foundation.

[0024] Description of reference numerals:

[0025] 1. Molten sulfur heat storage tank; 11. Heat exchange tube; 12. Electric heater; 13. First heating element; 14. Second heating element; 15. Molten sulfur inlet pipe; 16. Molten sulfur outlet pipe; 17. Agitator; 18. Top cover; 21. First water inlet pipe; 22. Second water inlet pipe; 23. Water pump; 24. First valve; 31. First water outlet pipe; 32. Second water outlet pipe; 33. Buffer tank; 34. Second valve; 35. First electric-controlled valve; 36. Temperature sensor; 4. First bridge circuit; 41. Water heater; 5. Second bridge circuit; 51. Second electric-controlled valve; 6. Third bridge circuit; 61. Third electric-controlled valve; 7. Molten sulfur module; 71. Molten sulfur kettle; 711. Solid sulfur feed port; 712. First tail gas pipe; 713. Viscosity reducer feed pipe; 714. Molten sulfur outlet pipe; 715. Agitation device; 72. Steam pipe; 73. Condensate pipe; 74. Steam coil; 8. Tail gas treatment module; 81. Alkali washing tower; 82. Tail gas inlet pipe; 83. Alkali liquid spray pipe; 84. Tower bottom liquid outlet pipe; 85. Liquid return pump; 86. Liquid return pipe; 87. Second spray pipe; 88. Waste liquid outlet pipe; 9. Accidental sulfur discharge pool; 91. Sulfur discharge pipe; 92. Second tail gas pipe; 101. Nitrogen main pipe; 102. First nitrogen pipe; 103. Second nitrogen pipe. DETAILED DESCRIPTION

[0026] The following will describe the utility model concepts of the present disclosure using terms commonly used by those skilled in the art to convey the essence of their work to other persons skilled in the art. However, these utility model concepts can be embodied in many different forms and should not be considered as limited to the embodiments described herein.

[0027] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. Figure 2 The diagram in the red box and the attached Figure 1 Basically the same, so in the attached Figure 2 No duplicate marking is performed.

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0029] This embodiment proposes a high-temperature molten sulfur heat storage and hot water supply system for oil fields, as shown in the attached Figure 1 As shown, the system includes a molten sulfur heat storage tank 1, a water inlet pipeline, and a water outlet pipeline. In the direction of water flow, the water inlet pipeline includes a first water inlet pipe 21, a water pump 23, and a second water inlet pipe 22 connected in sequence, and the water outlet pipeline includes a first water outlet pipe 31, a buffer tank 33, and a second water outlet pipe 32 connected in sequence. Accordingly, the water inlet end of the first water inlet pipe 21 can be regarded as the water inlet side of the system, and the water outlet end of the second water outlet pipe 32 can be regarded as the water outlet side of the system.

[0030] The molten sulfur heat storage tank 1 has a molten sulfur storage chamber for accommodating and storing molten sulfur. The molten sulfur heat storage tank 1 includes an electric heater 12 for heating the molten sulfur, especially using valley electricity to heat the molten sulfur.

[0031] A heat exchange pipe 11 is provided in the molten sulfur heat storage tank 1 , the inlet of the heat exchange pipe 11 is connected to the outlet of the second water inlet pipe 22 , and the outlet of the heat exchange pipe 11 is connected to the inlet of the first water outlet pipe 31 .

[0032] Heated return water (approximately 40°C) from the oilfield enters the system through the first water inlet pipe 21. Driven by a water pump 23, the return water flows sequentially through the second water inlet pipe 22 and the heat exchange pipe 11. Through the heat exchange pipe 11, it exchanges heat with the high-temperature molten sulfur in the molten sulfur heat storage tank 1, generating hot water (approximately 80°C). This hot water then flows sequentially through the first water outlet pipe 31, the buffer tank 33, and the second water outlet pipe 32 before being returned to the oilfield to heat the oil pipeline. Heat for the molten sulfur is primarily supplied by the system during off-peak hours, when the system heats the molten sulfur via the electric heater 12, storing the heat within the molten sulfur.

[0033] This application improves upon the conventional heating system currently used in oil fields. While providing hot water to oil pipelines, it also utilizes high-temperature molten sulfur heat storage to shift electricity peaks and fill valleys. This avoids the use of conventional boilers and fully utilizes off-peak periods for heat storage and heat supply. During peak periods, only high-temperature molten sulfur heat storage can be used for heat supply, effectively shifting electricity peaks and filling valleys, which also helps reduce electricity costs. Furthermore, the provision of a buffer tank 33 effectively buffers fluctuations in hot water output in the system, ensuring that the system can stably provide hot water.

[0034] The utility model proposes a novel high-temperature molten sulfur heat storage and hot water supply system for oil fields, which uses molten sulfur as the heat storage medium. Compared with molten salt heat storage and solid heat storage, it has obvious cost advantages, is safe and reliable, and is easy to maintain.

[0035] Heat storage stage: During off-peak or abundant electricity periods, excess electricity is converted into heat energy through the electric heater 12 and used to heat the molten sulfur in the storage tank, bringing the molten sulfur to a higher temperature (about 430°C). In this process, the heat energy is stored in the form of sensible heat of the molten sulfur.

[0036] Heat release phase: When heat is needed, especially during off-peak hours, the heat stored in the high-temperature molten sulfur is transferred to water through heat exchange tubes 11 of the molten sulfur heat storage tank 1 via a partitioning heat exchanger, generating hot water or steam. This heat is then released for use in the oilfield. During this process, the temperature of the high-temperature molten sulfur gradually decreases, eventually reaching a low temperature (approximately 130°C). The heat release process then ceases, preparing for the next heat storage phase.

[0037] It should be noted that the molten sulfur used in this application utilizes industrial pure sulfur or modified molten sulfur with added viscosity reducers such as halogens, hydrogen sulfide, and hydrogen persulfide as the heat storage medium. Modified molten sulfur is preferred in this application because industrial pure sulfur has a higher viscosity and poorer fluidity than modified molten sulfur, requiring more heat exchange area for partition-type heat exchange.

[0038] The system includes a first bridge circuit 4, the inlet of which is connected to the second water inlet pipe 22, and the outlet of which is connected to the first water outlet pipe 31. A water heater 41 is provided in the first bridge circuit 4, and valves are provided at both the inlet and outlet of the water heater 41. Thus, by providing the first bridge circuit 4 between the second water inlet pipe 22 and the first water outlet pipe 31, and by additionally providing the water heater 41 in parallel with the molten sulfur heat storage tank 1, the system allows conventional water heating via the first bridge circuit 4 to ensure a continuous supply of hot water during special periods, such as when the molten sulfur heat storage tank 1 is shut down for maintenance. Of course, the molten sulfur heat storage tank 1 and the water heater 41 can also operate simultaneously, with the water heater 41 being used for supplemental heating in certain special circumstances.

[0039] Specifically, a first valve 24 is provided in the second water inlet pipe 22, and a second valve 34 is provided in the first water outlet pipe 31. The inlet of the first bridge circuit 4 is located upstream of the first valve 24 along the flow direction of water in the second water inlet pipe 22, and the outlet of the first bridge circuit 4 is located downstream of the second valve 34 along the flow direction of water in the first water outlet pipe 31. During special periods, such as when the molten sulfur heat storage tank 1 needs to be shut down for maintenance, the first and second valves 24 and 34 can be closed, and the valves at the inlet and outlet of the water heater 41 can be opened, allowing regular water heating to be performed via the first bridge circuit 4 to maintain continuous operation of the system.

[0040] Because the system's heat release phase involves a non-steady-state heat transfer process, where the high-temperature molten sulfur cools from 430°C to 130°C. During the initial heat release phase, the molten sulfur is at a high temperature, leading to a significant temperature difference between the molten sulfur and the water. This results in excessive heat flow and excessively high temperatures in the hot water generated after heat exchange in the molten sulfur heat storage tank 1, resulting in wasted heat. To this end, the system includes a second bridge circuit 5, the inlet of which is connected to the second water inlet pipe 22 and the outlet of which is connected to the first water outlet pipe 31. A second electrically controlled valve 51 is disposed within the second bridge circuit 5. A temperature sensor 36 is disposed within the first water outlet pipe 31, downstream of the outlet of the second bridge circuit 5 along the direction of water flow in the first water outlet pipe 31.

[0041] Thus, the system sets a second bridge circuit 5 between the second water inlet pipe 22 and the first water outlet pipe 31. When the temperature of the hot water formed after heat exchange is too high, the second electrically controlled valve 51 is opened to allow a portion of the 40°C return water in the water inlet line to pass through the second bridge circuit 5 and enter the first water outlet pipe 31. This portion of 40°C return water mixes with the hot water formed after heat exchange, so that the mixed water temperature meets the requirement of 80°C. While ensuring that the oil pipeline is provided with hot water of the required temperature, the output hot water temperature is prevented from being too high, which can effectively avoid heat waste in the initial stage of heat release and also increase the supply of hot water. Preferably, in the direction of water flow along the second water inlet pipe 22, the inlet of the second bridge circuit 5 is located downstream of the first valve 24, and in the direction of water flow along the first water outlet pipe 31, the outlet of the second bridge circuit 5 is located upstream of the second valve 34.

[0042] Because the temperature of the hot water produced after heat exchange may not reach 80°C in the later stages of the heat release phase, the system cannot guarantee the supply of hot water of the required temperature to the oil pipeline. To this end, the system includes a third bridge circuit 6, the inlet of which is connected to the first water outlet pipe 31, and the outlet of which is connected to the first water inlet pipe 21. A third electrically controlled valve 61 is disposed in the third bridge circuit 6; a first electrically controlled valve 35 is disposed in the first water outlet pipe 31, and is located downstream of the inlet of the third bridge circuit 6 along the direction of water flow in the first water outlet pipe 31. Therefore, in the later stage of the heat release phase, the opening of the first electrically controlled valve 35 can be reduced, or even closed, and the third electrically controlled valve 61 can be opened, allowing the hot water after heat exchange to flow from the third bridge 6 into the first water inlet pipe 21. The hot water is then pumped into the molten sulfur heat storage tank 1 by the water pump 23 for further heat exchange. This cycle is repeated to ensure that the water and the molten sulfur are fully heat exchanged in the later stage of the heat release phase to reach the required water temperature of 80°C. The water is then sent to the buffer tank 33 to ensure that the system can still provide hot water of the required temperature to the oil pipeline in the later stage of the heat release phase. Of course, in the later stage of the heat release phase, to ensure the supply of hot water, the electric heater 12 can also be used for supplementary heating.

[0043] At the same time, the present application preferably sets the first bridge 4, the second bridge 5, and the third bridge 6 at the same time. However, since three bridges are set at the same time, it is necessary to avoid unnecessary water crossflow and ensure the normal regulation of the water flow direction and water temperature in the system. To this end, the present application further specifies the settings of the three bridges and related valves and other components. Specifically:

[0044] The outlet of the third bridge circuit 6 is connected to the first water inlet pipe 21, ensuring direct communication with the water inlet of the water pump 23. Along the flow direction of water in the second water inlet pipe 22, the inlet of the first bridge circuit 4, the first valve 24, and the inlet of the second bridge circuit 5 are sequentially arranged. Along the flow direction of water in the first water outlet pipe 31, the outlet of the second bridge circuit 5, the inlet of the third bridge circuit 6, the first electrically controlled valve 35, the second valve 34, and the outlet of the first bridge circuit 4 are sequentially arranged. The provision of the first electrically controlled valve 35 eliminates the need for the second valve 34. By orderly arranging the three bridge circuits and their associated valves and other components, water can be prevented from flowing between different pipelines. This also facilitates the overall system's control of water flow direction and temperature, ensuring proper operation.

[0045] Furthermore, a temperature sensor 36 is provided in the first water outlet pipe 31, and the temperature sensor 36 is located between the outlet of the second bridge circuit 5 and the inlet of the third bridge circuit 6. Thus, with only one temperature sensor 36, the water flow in the second bridge circuit 5 can be adjusted according to the temperature of the hot water after mixing, and the circulating flow of the water in the third bridge circuit 6 can be adjusted according to the temperature of the hot water after heat exchange. This eliminates the need for multiple temperature sensors, simplifies component configuration, and prevents errors or interference in system operation and control.

[0046] The buffer tank 33 is provided with a water level sensor for detecting the water level in the buffer tank 33 .

[0047] Accordingly, based on the above system, in order to improve the intelligent operation of the system and the accuracy of regulation, the present application further proposes a control method for a high-temperature molten sulfur heat storage hot water supply system for oil fields, the method comprising:

[0048] S1, real-time detection of the water temperature T of the first water outlet pipe 31;

[0049] The water temperature T is preferably detected by a temperature sensor 36 located between the outlet of the second bridge 5 and the inlet of the third bridge 6 .

[0050] S2. Determine whether T>85°C; if so, increase the opening of the second electrically controlled valve 51 in the second bridge circuit 5 and return to step S1; if not, proceed to step S3;

[0051] When T>85°C, the return water at 40°C is mixed with the hot water with a high temperature formed after heat exchange through the second bridge 5 to avoid heat waste caused by the hot water having an excessively high temperature.

[0052] S3, determine whether T < 80°C; if so, proceed to step S4; if not, keep the first electronically controlled valve 35 open and the system maintains normal operation;

[0053] Among them, when 80℃≤T≤85℃, it means that the system can produce hot water required by the oil field, and the system can continue to operate.

[0054] S4, determining whether the second electrically controlled valve 51 is in a fully closed state; if so, proceeding to step S5; if not, reducing the opening of the second electrically controlled valve 51 and returning to step S1;

[0055] S5 , opening the third electrically controlled valve 61 in the third bridge circuit 6 , and closing the first electrically controlled valve 35 .

[0056] Steps S4-S5 are performed under the condition that T is less than 80°C. First, it is determined whether the second electrically controlled valve 51 is fully closed to avoid the situation where the hot water temperature is insufficient due to excessive low-temperature return water transported by the second bridge circuit 5. If the second electrically controlled valve 51 is fully closed, it means that the insufficient hot water temperature may be due to the smaller heat transfer temperature difference between the molten sulfur and the water in the late heat release stage. It is necessary to close the first electrically controlled valve 35 and open the third electrically controlled valve 61. The water after a single heat exchange is recycled to the molten sulfur heat storage tank 1 through the third bridge circuit 6 for further heat exchange. After two or more heat exchanges, sufficient heat exchange between the water and the molten sulfur is guaranteed in the late heat release stage to meet the water temperature requirement of 80°C.

[0057] Therefore, the control method proposed in this application based on the system is mainly aimed at the regulation of the system during the heat release phase (especially the process of turning off the electric heater 12 of the molten sulfur heat storage tank 1 and only producing hot water through the molten sulfur heat storage). Whether in the early stage of the heat release phase or in the later stage of the heat release phase, it can ensure that the system stably provides hot water at 80°C-85°C to the outside, avoiding the output hot water temperature being too high or too low, so that energy can be maximized and unnecessary waste of heat can be avoided. Accordingly, the control method can also effectively improve the intelligence level of the system operation and the accuracy of the regulation, providing a guarantee for the smooth operation of the system.

[0058] In step S3, while the first electrically controlled valve 35 is kept open and the system maintains normal operation, the following steps are performed: real-time detection of the water level H within the buffer tank 33 is performed to determine whether H is less than a first preset water level value; if so, an alarm is generated; if not, the process returns to step S1. During normal operation, the buffer tank 33 buffers the water flow and dynamically balances the inflow and outflow of water, so extremely low water levels within the buffer tank 33 are rare. If this occurs, an alarm should be generated as soon as possible to notify the operator to inspect relevant equipment, pipelines, and detection devices. This facilitates timely handling of individual emergencies or failures during normal system operation.

[0059] In addition, step S5 of the control method includes:

[0060] S51, opening the third electrically controlled valve 61 in the third bridge circuit 6, and closing the first electrically controlled valve 35;

[0061] S52, real-time detection of the water level H in the buffer tank 33, and determination of whether H is less than a second water level preset value; if so, proceed to step S53; if not, return to step S1;

[0062] S53 , turning on the first bridge circuit 4 and the water heater 41 in the first bridge circuit 4 , and / or turning on the electric heater 12 of the molten sulfur heat storage tank 1 .

[0063] Therefore, during the circulation heat exchange process in step S5, the dynamic balance of the water flow in and out of the buffer tank 33 is often disrupted, causing the liquid level in the buffer tank 33 to gradually decrease. Therefore, the present application performs real-time detection of the water level height in the buffer tank 33, and when the water level is low, promptly turns on the water heater 41 and / or the electric heater 12 to increase the amount of hot water produced by the system per unit time and ensure the normal hot water supply of the system.

[0064] The first and second water level preset values ​​can be set based on actual capacity (total water level) of the buffer tank 33, the minimum amount of hot water required per unit time by the hot water demand side, and other practical circumstances. This application does not impose any specific restrictions on this, but only uses individual values ​​as examples to facilitate understanding of the solution. For example, the first and second water level preset values ​​are 30% of the actual total water level of the buffer tank 33, and the second water level preset value is 20% of the actual total water level of the buffer tank 33. Furthermore, the first and second water level preset values ​​can be equal or unequal, and both need to be determined based on practical circumstances.

[0065] Compared with setting up the first bridge circuit 4, the second bridge circuit 5, and the third bridge circuit 6 at the same time, the present application may also not set up the first bridge circuit 4, but directly set the water heater 41 in the second water outlet pipe 32, that is, the water heater 41 is located downstream of the buffer tank 33, so that the buffer tank 33 only buffers the hot water produced by the molten sulfur heat storage tank 1. At the same time, the water heater 41 can not only provide a certain hot water buffer space, but also when the temperature of the hot water produced by the molten sulfur heat storage tank 1 is insufficient or the temperature of the water flowing out of the buffer tank 33 is insufficient, the water heater 41 can be turned on for direct heat supplement to ensure that the system ultimately provides hot water that meets the required temperature.

[0066] In the system, the molten sulfur heat storage tank 1 is an important hot water production equipment. Figure 1 , this application further introduces it.

[0067] The molten sulfur heat storage tank 1 comprises a cylinder, a top cover plate 18, and a bottom cover plate. The top end of the cylinder is connected to the top cover plate 18, preferably via a flanged, sealed connection. The bottom end of the cylinder is connected to the bottom cover plate, preferably via a flanged, sealed connection, and provided with a graphite gasket. Preferably, the cylinder has a hollow cylindrical sidewall, and both the top cover plate 18 and the bottom cover plate are circular.

[0068] A stirrer 17 is disposed in the center of the top cover plate 18. The stirrer 17 includes a motor, a base, a stirring shaft, and a stirring paddle. The base of the stirrer 17 is connected to the top cover plate 18, which may be sealed by a flange. At least the stirring shaft and the stirring paddle are disposed within the molten sulfur storage chamber of the molten sulfur heat storage tank 1 to stir the molten sulfur to ensure a uniform temperature distribution of the molten sulfur within the molten sulfur heat storage tank 1. Preferably, the stirring shaft coincides with the central axis of the top cover plate 18.

[0069] The heat exchange tube 11 includes a water inlet manifold, a water outlet combined pipe, and a plurality of U-shaped branches. The U-shaped branches are arranged in the outer space of the agitator 17 in the form of a circular array, that is, the U-shaped branches are arranged around the agitator 17 without generating spatial interference; the U-shaped branches pass through the top cover plate 18 and extend into the molten sulfur storage chamber of the molten sulfur heat storage tank 1, so that the water in the pipeline can exchange heat with the molten sulfur in a partition-type manner. While passing through the top cover plate 18, the U-shaped branches are integrally connected to the top cover plate 18, preferably by welding, to ensure sealing. Therefore, under the action of the agitator 17, the present application sets a plurality of evenly arranged U-shaped branches in the molten sulfur heat storage tank 1, which is conducive to increasing the heat exchange area between water and molten sulfur on the one hand, and ensuring the uniformity of heat exchange at various positions in the molten sulfur heat storage tank 1 on the other hand. Overall, it helps to improve the heat exchange efficiency between water and molten sulfur.

[0070] The water inlets of all U-shaped branch pipes are connected to the water inlet collecting pipe, and the water outlets of all U-shaped branch pipes are connected to the water outlet combining pipe; the water inlet of the water inlet collecting pipe serves as the inlet of the heat exchange pipe 11 and is connected to the outlet of the second water inlet pipe 22; the water outlet of the water outlet combining pipe serves as the outlet of the heat exchange pipe 11 and is connected to the inlet of the first water outlet pipe 31.

[0071] The electric heater 12 is disposed below the bottom cover (or in the direction away from the cylinder). The electric heater 12 includes a plurality of first heating elements 13 and a plurality of second heating elements 14. The first heating elements 13 and the second heating elements 14 each vertically extend through the bottom cover and into the molten sulfur storage chamber of the molten sulfur heat storage tank 1. The extension length of the first heating elements 13 is greater than that of the second heating elements 14. The first heating elements 13 and the second heating elements 14 are integrally connected to the bottom cover, preferably by welding and sealing.

[0072] Among them, the first heating element 13 can be extended to the molten sulfur liquid level of the molten sulfur heat storage tank 1, and mainly bears the heating load of the molten sulfur in the heat storage stage; the second heating element 14 can be extended to the bottom space of the molten sulfur storage chamber, and it mainly bears the heat insulation load of the molten sulfur heat storage tank 1 during the discharge of molten sulfur, to avoid the solidification of the molten sulfur during the discharge of the molten sulfur. At the same time, the second heating element 14 can also take into account a certain amount of heating load on the molten sulfur in the heat storage stage. This setting of the heating element can not only ensure the normal heating of the molten sulfur, but also avoid the solidification of the molten sulfur during the discharge of the molten sulfur. In addition, the first heating element 13 can be turned off during the discharge of the molten sulfur, and only the second heating element 14 can be turned on to avoid the dry burning of the first heating element 13 as the molten sulfur liquid level decreases. Among them, it should be noted that the discharge of molten sulfur will occur in the scenario of molten sulfur replacement, parking for maintenance, or other emergency situations.

[0073] Taking into account the arrangement of the heat exchange tube 11 and the agitator 17, the first heating element 13 and the second heating element 14 are arrayed on the same circumference in an alternating manner, that is, the first heating element 13 and the second heating element 14 are alternately arranged in sequence on the same circle; at the same time, the first heating element 13 and the second heating element 14 are both arranged in the outer space of the agitator 17. Further, they can also be arranged in the outer space of the U-shaped branch, but preferably, the first heating element 13 is located between any two adjacent U-shaped branches, and the second heating element 14 is also located between any two adjacent U-shaped branches, as long as no contact or spatial interference between the components occurs.

[0074] The molten sulfur heat storage tank 1 can be filled with molten sulfur, but due to the temperature-dependent volume change of molten sulfur, some space is reserved for expansion. A molten sulfur inlet pipe 15 is located on the upper portion of the cylinder of the molten sulfur heat storage tank 1 for adding molten sulfur. A molten sulfur outlet pipe 16 is located on the bottom cover of the molten sulfur heat storage tank 1 for discharging the molten sulfur from the cylinder. Aside from the sulfur inlet port corresponding to the molten sulfur inlet pipe 15, the cylinder of the molten sulfur heat storage tank 1 has no other openings, minimizing the possibility of thermal stress concentration in the cylinder wall caused by internal temperature fluctuations and reducing the possibility of longitudinal tearing. Accordingly, the molten sulfur heat storage tank 1's cylinder, top cover 18, bottom cover, agitator 17, and other components are connected using flanges, making them easy to disassemble and assemble. This allows for maintenance after disassembly. This eliminates the need for manholes in the cylinder or cover structure, eliminating the impact of manholes on the cylinder's stress strength design. Furthermore, maintenance personnel no longer need to perform maintenance work in a confined or relatively closed space, significantly improving the safety factor of maintenance. Accordingly, supports are provided on the outer wall of the molten sulfur heat storage tank 1, allowing the entire molten sulfur heat storage tank 1 to be fixed to a frame at a certain height above the ground.

[0075] In the present application, the U-shaped branch of the heat exchange tube 11, the first heating element 13, and the second heating element 14 are all extended in the vertical direction and their arrangement, on the one hand, fully considers the temperature uniformity of the molten sulfur, which helps to ensure uniform temperature distribution and uniform heat transfer in the molten sulfur heat storage tank 1, and on the other hand, it also helps to make full use of the latent heat of liquefaction of the molten sulfur and even the phase change heat. Specifically, in the heat exchange process between molten sulfur and water in the present application, the minimum temperature of the molten sulfur exotherm can be as low as 90°C, which is lower than the freezing point of molten sulfur (114°C), so that the heat storage density of the device per unit volume is increased and the investment cost is lower.

[0076] In addition, as attached Figure 2-3 As shown, the system includes a sulfur melting module 7 and an accident sulfur discharge pool 9. The sulfur melting module 7 has a sulfur outlet pipe 714 connected to the sulfur inlet pipe 15 of the sulfur melting heat storage tank 1, and the sulfur discharge pipe 91 of the accident sulfur discharge pool 9 is connected to the sulfur outlet pipe 16 of the sulfur melting heat storage tank 1, so that sulfur is melted by the sulfur melting module 7 and then fed into the sulfur melting heat storage tank 1. When it is necessary to discharge molten sulfur from the sulfur melting heat storage tank 1, the molten sulfur can be discharged into the accident sulfur discharge pool 9, so that in the event of sulfur replacement, shutdown and maintenance, or other emergency situations, the molten sulfur in the sulfur melting heat storage tank 1 can be discharged, and molten sulfur can also be added to the sulfur melting heat storage tank 1. The accident sulfur discharge pool 9 can be a pool for holding molten sulfur or a sealed container.

[0077] For the molten sulfur module, if attached Figure 3 As shown, the sulfur melting module 7 includes a sulfur melting kettle 71 and a sulfur melting pipeline. A solid sulfur feed port 711 is provided on the top of the sulfur melting kettle 71 for feeding sulfur into the sulfur melting kettle 71. A molten sulfur outlet pipe 714 is provided at the bottom of the sulfur melting kettle 71 for discharging molten sulfur. The sulfur melting pipeline includes a steam pipe 72, a steam coil 74, and a condensed water pipe 73 connected in sequence. The steam coil 74 is provided in the sulfur melting kettle 71, the inlet of the steam coil 74 is connected to the steam pipe 72, and the outlet of the steam coil 74 is connected to the condensed water pipe 73, so that the external high-temperature and high-pressure water vapor is transported from the steam pipe 72 to the steam coil 74, so that the water vapor and the sulfur undergo a wall-to-wall heat exchange. The condensed water formed after the water vapor releases heat is discharged from the condensed water pipe 73. As the heat exchange proceeds, the solid sulfur gradually turns into molten sulfur, and then is transported to the molten sulfur heat storage tank 1 through the molten sulfur outlet pipe 714. Preferably, the sulfur melting kettle 71 is provided with a stirring device 715 for stirring during the sulfur melting process to improve the heat exchange efficiency between water vapor and sulfur and improve the sulfur melting efficiency.

[0078] The molten sulfur in this application preferably adopts modified molten sulfur with added viscosity reducer. Accordingly, the molten sulfur kettle 71 is provided with a viscosity reducer feed pipe 713. There are two forms of feeding the viscosity reducer. The viscosity reducer in gaseous form can be directly introduced into the molten sulfur kettle 71 to realize feeding; the viscosity reducer in solid or liquid form can be fed into the molten sulfur kettle 71 through conveying equipment such as a screw pump.

[0079] In addition, since sulfur will produce a certain amount of toxic gases such as hydrogen sulfide during the melting process, in order to avoid the accumulation and leakage of these toxic gases in the entire system, the daily operation safety of the system is guaranteed.

[0080] Reference Attachment Figure 2 , Attachment Figure 4 The system includes an exhaust gas treatment module 8 and a nitrogen main pipe 101. The exhaust gas treatment module 8 has an exhaust gas inlet pipe 82. A first nitrogen pipe 102 and a first exhaust gas pipe 712 are provided on the top of the sulfur melting kettle 71. One end of the nitrogen main pipe 101 is connected to an external nitrogen source, and the other end is connected to the first nitrogen pipe 102, for introducing nitrogen for purging into the sulfur melting kettle 71. The first exhaust gas pipe 712 is connected to the exhaust gas inlet pipe 82, for sending the toxic gas in the sulfur melting kettle 71 into the exhaust gas treatment module 8 for treatment. Therefore, during the sulfur melting process of the sulfur melting kettle 71, by maintaining the pressure and nitrogen purge in the sulfur melting kettle 71, most of the toxic gases produced in the molten sulfur are sent to the exhaust gas treatment module 8 for treatment, which can remove most of the toxic gases produced during the sulfur melting process, greatly reducing the accumulation of toxic gases in the entire system, and also helping to avoid safety problems caused by toxic gas leakage.

[0081] In addition, a small amount of toxic gases such as hydrogen sulfide may be generated during the heating process of the molten sulfur in the molten sulfur storage tank 1. In order to reduce the safety risk of the system as much as possible, this application Figure 2 Keep the red box Figure 1The content is exactly the same, except that a second nitrogen pipe 103 is additionally provided on the top of the molten sulfur heat storage tank 1 (specifically, the top cover plate 18 of the molten sulfur heat storage tank 1), one end of the nitrogen main pipe 101 is connected to an external nitrogen source, and the other end is connected to the second nitrogen pipe 103; the accident sulfur discharge pool 9 is preferably a sealed container, and the accident sulfur discharge pool 9 has a second tail gas pipe 92, and the second tail gas pipe 92 is connected to the tail gas inlet pipe 82. Therefore, since the amount of toxic gas generated by the molten sulfur heat storage tank 1 is small, in the case of molten sulfur replacement, shutdown for maintenance, sudden accident, etc., when the molten sulfur in the molten sulfur heat storage tank 1 is discharged to the accident sulfur discharge pool 9, nitrogen of a certain pressure can be delivered to the molten sulfur heat storage tank 1 through the nitrogen main pipe 101. On the one hand, it is beneficial to speed up the discharge speed of the molten sulfur to a certain extent. On the other hand, a small amount of toxic gas in the molten sulfur heat storage tank 1 can be brought into the accident sulfur discharge pool 9 through the nitrogen, and then sent to the tail gas treatment module 8 through the second tail gas pipe 92 and the tail gas inlet pipe 82 for treatment. This process not only realizes the accelerated discharge of molten sulfur and harmful gases in the molten sulfur heat storage tank 1, but also helps to ensure a relatively safe and harmless environment in the molten sulfur heat storage tank 1. After the molten sulfur heat storage tank 1 is cleared and discharged, there is no need to perform additional detoxification operations on the molten sulfur heat storage tank 1. The molten sulfur heat storage tank 1 can be directly disassembled, cleaned, inspected and maintained, which greatly reduces the risk of poisoning by toxic gases such as hydrogen sulfide.

[0082] As for the tail gas treatment module 8, it is preferred not to open it during the normal operation stage of the molten sulfur heat storage tank 1, and to open it only during the sulfur melting process of the sulfur melting module 7 and the sulfur discharge process of the molten sulfur heat storage tank 1.

[0083] As attached Figure 4 As shown, the tail gas treatment module 8 includes an alkali washing tower 81, the tail gas inlet pipe 82 is connected to the middle part of the alkali washing tower 81, and is used to send toxic gases into the alkali washing tower 81 for treatment. An alkali liquid spray pipe 83 is provided at the top of the alkali washing tower 81, which is used to send alkali liquid into and spray it into the alkali washing tower 81; the bottom of the alkali washing tower 81 is provided with a bottom liquid outlet pipe 84, a return liquid pump 85, and a return liquid pipe 86 connected in sequence, and the return liquid pipe 86 is connected to the alkali liquid spray pipe 83, which is used to send the bottom liquid of the alkali washing tower 81 into the alkali liquid spray pipe 83 and spray it into the alkali washing tower 81, so as to improve the treatment effect of toxic gases and reduce the use of alkali liquid.

[0084] The liquid return pipe 86 is provided with a waste liquid outlet pipe 88 for discharging part of the tower bottom liquid into the downstream sewage treatment system.

[0085] In addition, a second spray pipe 87 is provided in the middle of the alkali washing tower 81, and the second spray pipe 87 is connected to the return liquid pipe 86; in the alkali washing tower 81, the spray end of the second spray pipe 87 is located above the outlet end of the tail gas inlet pipe 82, so that by providing the second spray pipe 87, a portion of the tower bottom liquid is sprayed above the outlet end of the tail gas inlet pipe 82, forming an additional spray absorption process for toxic gases, so that two spray absorption processes are formed for toxic gases in the entire alkali washing tower 81, so as to further improve the treatment effect of toxic gases.

[0086] When the alkali washing tower 81 is in operation, a certain liquid level must be maintained at its bottom. A liquid level gauge is provided in the alkali washing tower 81 to adjust the opening of the drain valve of the waste liquid outlet pipe 88 according to the liquid level at the bottom of the alkali washing tower 81. This prevents excessive discharge of liquid from causing the liquid level in the alkali washing tower 81 to be too low, or insufficient discharge of liquid from causing the liquid level in the alkali washing tower 81 to be too high. Furthermore, a pH detection device is provided in the bottom of the alkali washing tower 81 to detect the pH value of the bottom liquid. This allows for adjustments to be made to the alkali liquid supply, the amount of return liquid sprayed into the tower, and the partial discharge of the bottom liquid, based on the pH value.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-temperature molten sulfur heat storage and hot water supply system for oil fields, characterized in that: The system comprises a molten sulfur heat storage tank (1), a water inlet pipeline, and a water outlet pipeline. In the direction of water flow, the water inlet pipeline comprises a first water inlet pipe (21), a water pump (23), and a second water inlet pipe (22) connected in sequence, and the water outlet pipeline comprises a first water outlet pipe (31), a buffer tank (33), and a second water outlet pipe (32) connected in sequence; the molten sulfur heat storage tank (1) has a molten sulfur storage chamber for accommodating and storing molten sulfur, and the molten sulfur heat storage tank (1) comprises an electric heater (12); a heat exchange pipe (11) is provided in the molten sulfur heat storage tank (1), the inlet of the heat exchange pipe (11) is connected to the outlet of the second water inlet pipe (22), and the outlet of the heat exchange pipe (11) is connected to the inlet of the first water outlet pipe (31).

2. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 1, characterized in that: The system comprises a first bridge circuit (4), the inlet of the first bridge circuit (4) is connected to a second water inlet pipe (22), the outlet of the first bridge circuit (4) is connected to a first water outlet pipe (31), and a water heater (41) is provided in the first bridge circuit (4).

3. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 2, characterized in that: A first valve (24) is provided in the second water inlet pipe (22), and a second valve (34) is provided in the first water outlet pipe (31); in the direction of water flow in the second water inlet pipe (22), the inlet of the first bridge circuit (4) is located upstream of the first valve (24), and in the direction of water flow in the first water outlet pipe (31), the outlet of the first bridge circuit (4) is located downstream of the second valve (34).

4. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 1, characterized in that: The system comprises a water heater (41), and the water heater (41) is arranged in the second water outlet pipe (32).

5. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 1, characterized in that: The system comprises a second bridge circuit (5), the inlet of the second bridge circuit (5) is connected to a second water inlet pipe (22), the outlet of the second bridge circuit (5) is connected to a first water outlet pipe (31), and a second electrically controlled valve (51) is provided in the second bridge circuit (5).

6. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 5, characterized in that: A temperature sensor (36) is provided in the first water outlet pipe (31), and in the flow direction of water in the first water outlet pipe (31), the temperature sensor (36) is located downstream of the outlet of the second bridge (5).

7. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 1, characterized in that: The system comprises a third bridge circuit (6), the inlet of the third bridge circuit (6) is connected to the first water outlet pipe (31), the outlet of the third bridge circuit (6) is connected to the first water inlet pipe (21), and a third electrically controlled valve (61) is provided in the third bridge circuit (6).

8. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 7, characterized in that: A first electrically controlled valve (35) is provided in the first water outlet pipe (31), and in the direction of water flow in the first water outlet pipe (31), the first electrically controlled valve (35) is located downstream of the inlet of the third bridge circuit (6).

9. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 1, characterized in that: The system comprises a first bridge circuit (4), a second bridge circuit (5), and a third bridge circuit (6); a water heater (41) is provided in the first bridge circuit (4), a second electrically controlled valve (51) is provided in the second bridge circuit (5), and a third electrically controlled valve (61) is provided in the third bridge circuit (6); the outlet of the third bridge circuit (6) is connected to the first water inlet pipe (21); along the flow direction of water in the second water inlet pipe (22), the inlet of the first bridge circuit (4), the first valve (24), and the inlet of the second bridge circuit (5) are provided in sequence; along the flow direction of water in the first water outlet pipe (31), the outlet of the second bridge circuit (5), the inlet of the third bridge circuit (6), the first electrically controlled valve (35), and the outlet of the first bridge circuit (4) are provided in sequence.

10. The high-temperature molten sulfur heat storage and hot water supply system for oil fields according to claim 9, characterized in that: A temperature sensor (36) is provided in the first water outlet pipe (31), and the temperature sensor (36) is located between the outlet of the second bridge (5) and the inlet of the third bridge (6).

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