Energy-saving system for recycling double-heat-storage steam

Abstract

The invention relates to a double-heat-storage steam recycling energy-saving system which comprises a heat accumulator used for storing saturated steam from a steelmaking vaporization system, and an outlet of the heat accumulator is communicated with a hot steam heat storage heat exchanger. The superheated steam heat storage heat exchanger is used for heating and storing heat in a low-ebb electricity price time period and can heat saturated steam from the heat storage device in real time to form superheated steam, and an outlet of the superheated steam heat storage heat exchanger is communicated with a superheated steam utilization device. Dual heat storage is achieved through the steam and the heat storage medium, and the steam generation rule and the steam use rule can be coordinated; according to the invention, the peak-valley electricity price difference can be fully utilized, and the superheated steam can be stably produced with lower cost.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature flue gas waste heat recovery, and in particular to an energy-saving system for double heat storage steam circulation utilization. Background Art

[0002] In the steelmaking process, the most common heat recovery process is to recover the waste heat from high-temperature flue gas to generate steam. In the existing process, the steam generated by the converter flue gas vaporization flue often needs to be sent to the steam accumulator for storage, and the steam generated in this process is often saturated steam.

[0003] In the subsequent production processes related to steelmaking, such as RH furnaces and VD furnaces, superheated steam with higher parameters is generally required, so a matching steam superheating device is often required. Among them, the steam used in RH, VD and other processes is often operated continuously or with variable loads, but the steam produced by converter flue gas is often operated intermittently. The contradiction between the production rhythms of the two makes it difficult to control the operation of the heat accumulator and steam superheating device.

[0004] The prior art discloses a converter steam superheating device, which is connected between the converter flue and the steam pipeline, and solves the problem of unstable and uncontrollable superheat when the flue gas waste heat is recovered and utilized to produce superheated steam; however, this technology utilizes the converter flue gas waste heat, and the production rhythm and the converter production rhythm need to be highly coupled. If the rhythms do not match, operation and regulation are difficult; and this technology does not fully consider the production laws on the steam side.

[0005] Therefore, the inventor, relying on many years of experience and practice in related industries, proposes an energy-saving system for double heat storage steam recycling to overcome the defects of the prior art. Summary of the invention

[0006] The purpose of the present invention is to provide an energy-saving system for double heat storage steam circulation. The present invention realizes double heat storage through steam and heat storage medium, and can coordinate the steam production and steam use rules; the present invention can make full use of the peak-valley electricity price difference, and stably produce superheated steam at a lower cost.

[0007] The objective of the present invention is achieved by providing an energy-saving system for dual heat storage steam circulation, comprising a heat accumulator for storing saturated steam from a steelmaking vaporization system, wherein the outlet of the heat accumulator is connected to a hot steam heat storage heat exchanger, wherein the superheated steam heat storage heat exchanger is used for heating and storing heat during off-peak electricity price periods, and can heat the saturated steam from the heat accumulator in real time to form superheated steam, wherein the outlet of the superheated steam heat storage heat exchanger is connected to a hot steam utilization device.

[0008] In a preferred embodiment of the present invention, the energy-saving system of dual heat storage steam circulation utilization includes a hollow superheating circuit, the inner cavity of the superheating circuit constitutes a steam channel; the superheated steam heat storage heat exchanger covers at least part of the pipeline of the superheating circuit; the superheated steam heat storage heat exchanger includes an electrically heated heat storage medium layer arranged on the outside of the superheating circuit, and the saturated steam from the heat accumulator is heated to superheated steam in the steam channel by the thermal energy of the heat storage medium layer.

[0009] In a preferred embodiment of the present invention, the superheated steam heat storage heat exchanger includes a closed outer shell, and the superheating circuit is sealed and penetrates through the outer shell; the heat storage medium layer includes a medium layer outer wall arranged on the outside of the superheating circuit, and the space between the medium layer outer wall and the outer wall of the superheating circuit is filled with a heat storage medium that can flow and store heat, and the heat storage operating temperature of the heat storage medium is higher than the superheated steam temperature.

[0010] In a preferred embodiment of the present invention, an electric heating device is provided in the heat storage medium layer, and the electric heating device is used to heat the heat storage medium during a period of low electricity prices.

[0011] In a preferred embodiment of the present invention, the heat storage medium is thermal oil.

[0012] In a preferred embodiment of the present invention, the electric heating device is a spiral electric heating belt.

[0013] In a preferred embodiment of the present invention, a heat-insulating layer is provided between the heat-storage medium layer and the outer shell, and the heat-insulating layer is filled with heat-insulating material.

[0014] In a preferred embodiment of the present invention, the thermal insulation material is composite silicate.

[0015] In a preferred embodiment of the present invention, the superheated steam heat storage heat exchanger includes a forced flow device for driving the heat storage medium to flow.

[0016] In a preferred embodiment of the present invention, the inlet of the heat accumulator is connected to the steelmaking vaporization system through a saturated steam pipeline, the inlet of the superheated steam heat storage heat exchanger is connected to the outlet of the heat accumulator through the saturated steam pipeline, and the outlet of the superheated steam heat storage heat exchanger is connected to the superheated steam utilization device through a superheated steam pipeline; the superheating circuit is connected to the saturated steam pipeline and the superheated steam pipeline to form a through transport medium pipeline.

[0017] As described above, the energy-saving system of the dual heat storage steam cycle utilization of the present invention has the following beneficial effects:

[0018] The energy-saving system of dual heat storage steam circulation utilization of the present invention realizes dual heat storage through steam and heat storage medium, and can coordinate the rules of steam production and steam use. The present invention can make full use of the difference in peak and valley electricity prices to stably output superheated steam at a relatively low cost. The present invention has the following advantages: 1. Make full use of the abundant saturated steam in the factory and convert it into scarce superheated steam stably at a low price. 2. Harmonize the production rhythm of various processes to ensure the match between steam production and steam use. 3. Make full use of peak and valley electricity prices, store heat when electricity prices are low, and use heat when electricity prices are high, further saving costs. 4. The device and facilities are flexible, and the size of the device and system can be adjusted according to actual conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0020] in:

[0021] Figure 1 This is a schematic diagram of Example 1 of the energy-saving system for dual heat storage steam circulation utilization of the present invention.

[0022] Figure 2 This is a schematic diagram of Example 2 of the energy-saving system for dual heat storage steam circulation utilization of the present invention.

[0023] Figure 3 It is a schematic cross-sectional view of a superheated steam heat storage heat exchanger according to Example 1 of the present invention.

[0024] Figure 4 It is a schematic diagram of the operation rules of various parts of the energy-saving system for dual heat storage steam circulation utilization of the present invention.

[0025] In the figure:

[0026] 1. Steam drum;

[0027] 2. Heat storage device;

[0028] 3. Superheated steam heat storage heat exchanger;

[0029] 31. Electric heating device; 32. Forced flow device; 33. Heat storage medium layer; 331. Outer wall of medium layer; 332. Heat storage medium; 34. Insulation layer; 35. Shell;

[0030] 4. Saturated steam pipeline;

[0031] 5. Superheated steam pipeline;

[0032] 6. Overheating circuit;

[0033] 7. Superheated steam utilization device. DETAILED DESCRIPTION

[0034] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0035] The specific embodiments of the present invention described herein are only used to explain the purpose of the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be considered to belong to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on the other element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the internal communication of two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation method.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0037] like Figures 1 to 3 As shown, the present invention provides an energy-saving system for dual heat storage steam circulation utilization, including a heat accumulator 2 for storing saturated steam from a steelmaking vaporization system (generally from a steam drum 1 of the steelmaking vaporization system), the outlet of the heat accumulator 2 is connected to a hot steam heat storage heat exchanger 3, the superheated steam heat storage heat exchanger 3 is used for heating and storing heat during off-peak electricity price time periods, and can heat the saturated steam from the heat accumulator in real time to form superheated steam, and the outlet of the superheated steam heat storage heat exchanger 3 is connected to a hot steam utilization device 7.

[0038] The energy-saving system for double heat storage steam circulation utilization of the present invention realizes double heat storage through steam and heat storage medium, and can coordinate the rules of steam production and steam use.

[0039] The heat accumulator 2 and the superheated steam heat storage heat exchanger 3 form a dual heat storage structure of the present invention, both of which can realize heat storage. The heat accumulator 2 stores saturated steam, and according to the steam usage rule of the superheated steam utilization device 7 (the subsequent process, such as the RH or VD furnace), the saturated steam is sent to the superheated steam heat storage heat exchanger 3. The saturated steam is heated by the hot steam heat storage heat exchanger 3 to form superheated steam, and the superheated steam is transported to the superheated steam utilization device 7 (such as the RH or VD furnace) that needs steam.

[0040] The saturated steam produced by the steelmaking vaporization system can be stored inside the accumulator 2, which can be used to balance the gas production and gas use rules. Therefore, the accumulator 2 can well complete the function of transfer storage. Even if the saturated steam production rhythm does not match the superheated steam demand rhythm, it will not affect the steelmaking vaporization system to output saturated steam and the superheated steam utilization device 7 to use superheated steam, taking into account the steam side production rules and superheated steam use rules.

[0041] The superheated steam heat storage heat exchanger 3 can store the heat obtained from electric heating, and can also heat the saturated steam from the heat storage device, which can be used to balance the peak and valley electricity prices and the steam usage pattern.

[0042] The superheated steam heat storage heat exchanger 3 can heat the saturated steam produced by the steelmaking vaporization system to generate superheated steam; and the superheated steam heat storage heat exchanger 3 can utilize the peak and valley electricity prices to store heat during the valley electricity period, and release heat according to the superheated steam usage law to generate superheated steam.

[0043] The present invention effectively solves the problem in the existing steelmaking process that the saturated steam production rhythm and the superheated steam demand rhythm do not match each other, resulting in difficulties in the operation and regulation of the steam superheating device and the steam accumulator; the present invention provides a new steam recycling system, which fully utilizes the advantages of peak and valley electricity prices through the dual heat storage structure formed by the accumulator 2 and the superheated steam heat storage heat exchanger 3, so as to complete the connection between different production rhythms before and after the steam process at a lower cost.

[0044] The energy-saving system of the dual heat storage steam circulation utilization of the present invention can make full use of the difference in peak-valley electricity prices to stably produce superheated steam at a relatively low cost. The present invention has the following advantages: 1. It makes full use of the abundant saturated steam in the factory and converts it into scarce superheated steam at a low price and stably. 2. It coordinates the production rhythm of various processes to ensure the consistency between steam production and steam use. 3. It makes full use of peak-valley electricity prices, stores heat when electricity prices are low, and uses heat when electricity prices are high, further saving costs. 4. The device and facilities are flexible, and the size of the device and system can be adjusted according to actual conditions.

[0045] Further, if Figure 1 , Figure 2 , Figure 3As shown, the energy-saving system of dual heat storage steam circulation utilization includes a hollow superheating circuit 6, the inner cavity of the superheating circuit 6 constitutes a steam channel; the superheated steam heat storage heat exchanger 3 covers at least part of the pipeline of the superheating circuit 6; the superheated steam heat storage heat exchanger 3 includes an electrically heated heat storage medium layer 33 arranged on the outside of the superheating circuit 6, and the saturated steam from the heat accumulator 2 is heated to superheated steam in the steam channel by the heat energy of the heat storage medium layer 33.

[0046] Further, if Figure 1 , Figure 2 , Figure 3 As shown, the superheated steam heat storage heat exchanger 3 is a closed tubular container; the superheated steam heat storage heat exchanger 3 includes a closed shell 35, and the superheating circuit 6 is sealed and penetrated through the shell 35; the heat storage medium layer 33 includes a medium layer outer wall 331 arranged on the outside of the superheating circuit, and the space between the medium layer outer wall 331 and the outer wall of the superheating circuit 6 is filled with a heat storage medium 332 that can flow and store heat (with a certain flow capacity and strong heat storage capacity), and the heat storage operation temperature of the heat storage medium 332 is higher than the superheated steam temperature. The heat storage operation temperature of the heat storage medium 332 is generally above 300°C, and the common temperature of superheated steam is generally 250°C.

[0047] Further, if Figure 1 , Figure 2 , Figure 3 As shown, an electric heating device 31 is arranged in the heat storage medium layer 33, and the electric heating device 31 is used to heat the heat storage medium 332 during the off-peak electricity price period. The electric heating device 31 consumes electric energy to heat the heat storage medium 332.

[0048] The electric heating device 31 operates intermittently according to the peak and valley electricity prices. When the electricity price is low, the heat storage medium 332 is heated. The heat storage medium 332 can heat the saturated steam to convert it into superheated steam.

[0049] Furthermore, the heat storage medium 332 can be a flowing medium such as molten salt, heat transfer oil, a mixed fluid with solid particles, etc., preferably heat transfer oil.

[0050] During the off-peak electricity price period, the heat storage medium 332 in the superheated steam heat storage heat exchanger 3 is electrically heated to increase its temperature. The heat is stored in the heat storage medium 332 and supplied to the superheating circuit 6 in real time to heat the saturated steam.

[0051] Furthermore, the electric heating device 31 is a spiral electric heating belt.

[0052] Further, if Figure 1 , Figure 2 , Figure 3 As shown, a heat-insulating layer 34 is provided between the heat-storage medium layer 33 and the outer shell 35 , and the heat-insulating layer 34 is filled with heat-insulating material.

[0053] Furthermore, the thermal insulation material is composite silicate.

[0054] Further, if Figure 2 As shown, the superheated steam heat storage heat exchanger 3 includes a forced flow device 32 for driving the heat storage medium 332 to flow.

[0055] Further, if Figure 1 , Figure 2 As shown, the inlet of the heat accumulator 2 is connected to the steelmaking vaporization system through the saturated steam pipeline 4, the inlet of the superheated steam heat storage heat exchanger 3 is connected to the outlet of the heat accumulator 2 through the saturated steam pipeline 4, and the outlet of the superheated steam heat storage heat exchanger 3 is connected to the hot steam utilization device 7 through the superheated steam pipeline 5.

[0056] The superheating loop 6 is connected to the saturated steam pipeline 4 and the superheated steam pipeline 5 to form a through-conducting transport medium pipeline. When the saturated steam flows in the transport medium pipeline and passes through the superheating loop 6, it is heated to superheat by the high-temperature heat storage medium 332 outside to form superheated steam, which is used to supply the rear process facilities.

[0057] Example 1

[0058] like Figure 1 , Figure 3 As shown, the superheated steam heat storage heat exchanger 3 is a long tube-type closed container, and the superheating circuit 6 passes through the axis of the shell 35. With the container axis (the axis of the shell 35) as the center, from the inside to the outside, they are: the superheating circuit 6, the inside of the superheating circuit 6 is a steam channel, separated from the outside by the pipe wall; the heat storage medium layer 33, the inside of this layer is connected to the pipe wall of the superheating circuit 6 (wrapped abutment), and the outside is connected to the insulation layer 34 through the outer wall 331 of the medium layer (wrapped abutment), the heat storage medium layer 33 is filled with heat transfer oil as the heat storage medium 332, and the inside of this layer is provided with a spiral electric heating belt as the electric heating device 31; the insulation layer 34, the inside is connected to the outer wall 331 of the medium layer (wrapped abutment), and the outside is provided with a shell 35, and the insulation layer 34 is filled with composite silicate as the insulation material.

[0059] The superheated steam heat storage heat exchanger 3 is arranged in a sheathed manner on the outside of the superheating circuit 6 to form a sleeve structure, thereby saving space.

[0060] Example 2

[0061] like Figure 2 As shown, the superheated steam heat storage heat exchanger 3 is a closed container, the superheating circuit 6 is sealed and penetrates through the outer shell 35, the inner wall of the outer shell 35 is provided with a heat preservation layer 34, and the heat storage medium layer 33 is provided in the heat preservation layer 34. The superheating circuit 6 passes through the lower part of the heat storage medium layer 33, and a forced flow device 32 is provided in the heat storage medium layer 33 above the superheating circuit 6. The forced flow device 32 drives the heat storage medium 332 to flow to enhance heat exchange.

[0062] Example 3

[0063] The saturated steam produced by the steelmaking vaporization system is sent from the steam drum 1 to the heat accumulator 2 through the saturated steam pipeline 4 and stored in the heat accumulator 2. The saturated steam in the heat accumulator 2 is sent to the superheated steam heat storage heat exchanger 3 according to the steam usage rule of the superheated steam utilization device 7 (latter process, such as RH or VD furnace). The saturated steam entering the superheated steam heat storage heat exchanger 3 flows in the superheating circuit 6, is heated to superheat by the heat storage medium 332 outside the superheating circuit 6, becomes superheated steam, and is sent to the superheated steam utilization device 7 through the superheated steam pipeline 5.

[0064] During the off-peak electricity price period, the heat storage medium 332 in the superheated steam heat storage heat exchanger 3 is electrically heated to increase its temperature. The heat is stored in the heat storage medium 332 and supplied to the superheating circuit 6 in real time to heat the saturated steam.

[0065] Example 4

[0066] The operation rules of each part of the energy-saving system of the double heat storage steam cycle utilization of the present invention are as follows: Figure 4 As shown; in the figure, 1 means full load operation or all open, and 0 means stop operation or close.

[0067] During operation, the steelmaking vaporization system is frequently started and stopped. The saturated steam produced is sent to the heat accumulator 2, where it is stored to adjust the subsequent production rhythm. At the same time, the heat transfer oil in the superheated steam heat storage heat exchanger 3 is used to store heat, making full use of the local peak-valley electricity price difference to meet the needs of the subsequent VD vacuum pump room steam process.

[0068] The superheated steam heat storage heat exchanger 3 operates in real time; and the operation rule of the electric heating device 31 is controlled according to the local peak and valley electricity prices: when the electricity price is in the valley time period, the electric heating device 31 starts to store heat, and when the electricity price is in the peak time period, the electric heating device 31 does not start.

[0069] As described above, the energy-saving system of the dual heat storage steam cycle utilization of the present invention has the following beneficial effects:

[0070] The energy-saving system of dual heat storage steam circulation utilization of the present invention realizes dual heat storage through steam and heat storage medium, and can coordinate the rules of steam production and steam use. The present invention can make full use of the difference in peak and valley electricity prices to stably output superheated steam at a relatively low cost. The present invention has the following advantages: 1. Make full use of the abundant saturated steam in the factory and convert it into scarce superheated steam stably at a low price. 2. Harmonize the production rhythm of various processes to ensure the match between steam production and steam use. 3. Make full use of peak and valley electricity prices, store heat when electricity prices are low, and use heat when electricity prices are high, further saving costs. 4. The device and facilities are flexible, and the size of the device and system can be adjusted according to actual conditions.

[0071] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. An energy-saving system for double heat storage steam recycling, characterized in that: It includes a heat accumulator for storing saturated steam from a steelmaking vaporization system, the outlet of the heat accumulator is connected to a hot steam heat storage heat exchanger, the superheated steam heat storage heat exchanger is used for heating and storing heat during off-peak electricity price periods, and can heat the saturated steam from the heat accumulator in real time to form superheated steam, and the outlet of the superheated steam heat storage heat exchanger is connected to a hot steam utilization device.

2. The energy-saving system for double thermal storage steam circulation utilization according to claim 1, characterized in that: The energy-saving system for dual heat storage steam circulation utilization includes a hollow superheating circuit, the inner cavity of the superheating circuit constitutes a steam channel; the superheated steam heat storage heat exchanger covers at least part of the pipeline of the superheating circuit; the superheated steam heat storage heat exchanger includes an electrically heated heat storage medium layer arranged on the outside of the superheating circuit, and the saturated steam from the heat storage device is heated to superheated steam in the steam channel by the heat energy of the heat storage medium layer.

3. The energy-saving system for double thermal storage steam circulation utilization according to claim 2, characterized in that: The superheated steam heat storage heat exchanger includes a closed shell, and the superheating circuit is sealed and penetrates through the shell; the heat storage medium layer includes a medium layer outer wall arranged on the outside of the superheating circuit, and the space between the medium layer outer wall and the outer wall of the superheating circuit is filled with a heat storage medium that can flow and store heat, and the heat storage operating temperature of the heat storage medium is higher than the superheated steam temperature.

4. The energy-saving system for double thermal storage steam circulation utilization according to claim 3, characterized in that: An electric heating device is arranged in the heat storage medium layer, and the electric heating device is used to heat the heat storage medium during a low electricity price period.

5. The energy-saving system for double thermal storage steam circulation utilization according to claim 4, characterized in that: The heat storage medium is heat transfer oil.

6. The energy-saving system for double thermal storage steam circulation utilization according to claim 4, characterized in that: The electric heating device is a spiral electric heating belt.

7. The energy-saving system for double thermal storage steam circulation utilization according to claim 3, characterized in that: A heat-insulating layer is arranged between the heat-storage medium layer and the shell, and the heat-insulating layer is filled with heat-insulating material.

8. The energy-saving system for double thermal storage steam circulation utilization according to claim 7, characterized in that: The thermal insulation material is composite silicate.

9. The energy-saving system for double thermal storage steam circulation utilization according to claim 3, characterized in that: The superheated steam thermal storage heat exchanger includes a forced flow device for driving the thermal storage medium to flow.

10. The energy-saving system for double thermal storage steam circulation utilization according to claim 2, characterized in that: The inlet of the heat accumulator is connected to the steelmaking vaporization system through a saturated steam pipeline, the inlet of the superheated steam heat storage heat exchanger is connected to the outlet of the heat accumulator through the saturated steam pipeline, and the outlet of the superheated steam heat storage heat exchanger is connected to the superheated steam utilization device through a superheated steam pipeline; the superheating circuit is connected to the saturated steam pipeline and the superheated steam pipeline to form a through transport medium pipeline.

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