A power generation device based on the cold energy of a cryogenic propane tank

Abstract

This invention provides a power generation device based on the cold energy of a cryogenic propane tank, comprising a liquefied propane vaporizer, a propane heater, an intermediate medium vaporizer, a turbine generator set, and a dimethylamine circulating pump. The tube-side inlet of the liquefied propane vaporizer is connected to a cryogenic storage tank containing propane. The tube-side outlet of the liquefied propane vaporizer is connected to the tube-side inlet of the propane heater, and the tube-side outlet of the propane heater is connected to a propane pipeline network. Dimethylamine, after passing through the dimethylamine circulating pump, is connected to the tube-side inlet of the intermediate medium vaporizer. The tube-side outlet of the intermediate medium vaporizer is connected to the inlet of the turbine generator set, and the outlet of the turbine generator set is connected to the shell-side inlet of the liquefied propane vaporizer. The shell-side outlet of the liquefied propane vaporizer is connected to the inlet of the dimethylamine circulating pump. This invention achieves dual-sided cascaded energy recovery from cold to heat. Compared to traditional direct seawater heating schemes, the net power generation is increased.

Description

Technical Field

[0001] This utility model relates to the field of energy and power, and in particular to a power generation device based on the cold energy of a low-temperature propane tank. Background Technology

[0002] Cryogenic liquid hydrocarbons (such as propane and LNG) must be heated to the required process temperature via a vaporizer at the receiving terminal or transportation terminal before entering the downstream pipeline network. This phase change process releases a large amount of "cryogenic cold energy," typically ranging from -40°C to -10°C. Direct discharge into the ocean or air cooling not only wastes energy but may also cause localized cold pollution. Therefore, how to efficiently recover and upgrade this cold energy has become an important research direction in the energy field in recent years. The Organic Rankine Cycle (ORC) has been widely used in LNG cold energy power generation and waste heat power generation due to its advantages such as strong low-temperature adaptability, system simplicity, and flexible scale.

[0003] Currently, the industrial utilization of low-temperature propane cold energy mainly focuses on two low-grade methods: "producing low-temperature water" and "cold storage refrigeration." In the latter, room-temperature seawater or ethylene glycol solution is used to exchange heat with liquid propane in a vaporizer, producing 5°C–15°C chilled water or cold air, which is then sent to air conditioning, ice-making, or food refrigeration workshops. Some receiving stations also use this chilled water for cooling the gas turbine intake air to improve summer output. These methods require only traditional shell-and-tube heat exchangers and water pumps, are simple in process, and have low investment costs, making them widely adopted by most propane receiving stations.

[0004] However, the above-mentioned utilization methods have significant shortcomings: First, the cold energy is only reduced to low-grade chilled water or cold air, resulting in significant energy loss in exercisability and complete abandonment of power generation potential; second, to meet the process requirement of an external output temperature ≥10℃, a large amount of seawater or steam is still required for secondary heating, consuming additional pump power or steam; third, seawater cooling is greatly affected by seasonal temperature differences, resulting in excess cold energy when demand for chilled water decreases in winter, and insufficient cold energy during peak demand in summer, leading to a low system operating load rate throughout the year and poor economic efficiency. Therefore, there is an urgent need for an integrated solution that can efficiently upgrade low-temperature propane cold energy into electricity while simultaneously meeting the propane external output temperature requirements. Utility Model Content

[0005] This invention provides a power generation device based on the cold energy of a low-temperature propane tank, which solves the problem of low utilization efficiency in existing methods for utilizing the cold energy of low-temperature propane.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A power generation device based on the cold energy of a cryogenic propane tank includes a liquefied propane vaporizer, a propane heater, an intermediate medium vaporizer, a turbine generator set, and a dimethylamine circulating pump.

[0008] The inlet of the liquefied propane vaporizer is connected to a cryogenic storage tank containing propane. The outlet of the liquefied propane vaporizer is connected to the inlet of a propane heater, which is connected to a propane pipeline network. Dimethylamine, after passing through a dimethylamine circulation pump, is connected to the inlet of an intermediate medium vaporizer. The outlet of the intermediate medium vaporizer is connected to the inlet of a turbine generator set, which is connected to the shell-side inlet of the liquefied propane vaporizer. The shell-side outlet of the liquefied propane vaporizer is connected to the inlet of a dimethylamine circulation pump. The shell-side inlet of the propane heater is connected to a hot water pipe, and the shell-side outlet of the propane heater is connected to the shell-side inlet of the intermediate medium vaporizer. The shell-side outlet of the intermediate medium vaporizer is connected to a hot water return pipe.

[0009] Furthermore, it also includes a dimethylamine storage tank, which is connected to the inlet of the dimethylamine replenishment pump.

[0010] Furthermore, it also includes a dimethylamine replenishment pump, the inlet of which is connected to a dimethylamine storage tank, and the outlet of which is connected to a pipeline before the dimethylamine circulation pump.

[0011] Furthermore, a flow regulating valve is provided on the hot water pipeline between the shell-side outlet of the propane heater and the shell-side inlet of the intermediate medium vaporizer.

[0012] Furthermore, a gas-liquid separator is provided between the outlet of the turbine generator set and the shell-side inlet of the liquefied propane vaporizer, and the liquid phase outlet of the gas-liquid separator is connected to the inlet of the dimethylamine circulating pump through a return pipe.

[0013] Furthermore, the top of the dimethylamine storage tank is equipped with a pressure balancing pipe and a hand valve, and the pressure balancing pipe is connected to the outlet pipe of the turbine generator set.

[0014] The beneficial effects of this utility model are as follows:

[0015] This invention uses liquefied propane as the condensation cold source for ORC (Organic Refrigerant Gas) working fluid, while simultaneously using hot water originally used for propane vaporization as the ORC evaporation heat source, achieving dual-stage energy recovery on both the cold and hot sides. Compared to traditional direct seawater heating solutions, net power generation is increased.

[0016] This invention system simply embeds an ORC loop into the original propane gasification process, without increasing new fuel consumption, and the turbine exhaust heat is reused for the final heating of propane, ensuring that the output temperature is ≥10℃, which meets the receiving station specifications.

[0017] This invention uses dimethylamine as a single working medium, with a boiling point of -6.9℃, which is highly coupled with the propane vaporization temperature range, resulting in moderate condensation pressure and small turbine size. Furthermore, dimethylamine has low toxicity, a wide flammability limit, and high sensitivity for combustible gas detectors. It also has a dimethylamine odor, and the human body has a very low olfactory threshold for it, so even a small leak can be detected in time. Its safety is superior to that of light hydrocarbon working mediums.

[0018] The entire unit only requires the addition of two heat exchangers, one turbine generator set, and one circulating pump to operate in parallel or in series with the original propane gasifier; stable power generation can be achieved by adjusting the working fluid flow rate through the variable frequency circulating pump. Attached Figure Description

[0019] To more clearly illustrate the embodiments of this utility model or the technical solutions of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the device of this utility model.

[0021] Explanation of icon numbers:

[0022] 1. Liquefied propane vaporizer; 2. Propane heater; 3. Intermediate medium vaporizer; 4. Turbine generator set; 5. Dimethylamine circulating pump; 6. Cryogenic storage tank; 7. Hot water pipe; 8. Dimethylamine makeup pump; 9. Dimethylamine storage tank; 10. Gas-liquid separator. Detailed Implementation

[0023] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this utility model or its application or use. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0025] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0026] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0027] In the description of this utility model, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0028] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0029] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0030] This utility model provides a technical solution: a power generation device based on the cold energy of a low-temperature propane tank, such as... Figure 1 As shown, it includes a liquefied propane vaporizer 1, a propane heater 2, an intermediate medium vaporizer 3, a turbine generator set 4, and a dimethylamine circulating pump 5;

[0031] The inlet of the liquefied propane vaporizer 1 is connected to the cryogenic storage tank 6, which contains propane. The outlet of the liquefied propane vaporizer 1 is connected to the inlet of the propane heater 2, which is connected to the propane pipeline network. Dimethylamine is connected to the inlet of the intermediate medium vaporizer 3 after passing through the dimethylamine circulation pump 5. The outlet of the intermediate medium vaporizer 3 is connected to the inlet of the turbine generator set 4, which is connected to the shell inlet of the liquefied propane vaporizer 1. The shell outlet of the liquefied propane vaporizer 1 is connected to the inlet of the dimethylamine circulation pump 5. The shell inlet of the propane heater 2 is connected to the hot water pipe 7, and the shell outlet of the propane heater 2 is connected to the shell inlet of the intermediate medium vaporizer 3. The shell outlet of the intermediate medium vaporizer 3 is connected to the hot water return pipe.

[0032] It also includes a dimethylamine storage tank, which is connected to the inlet of the dimethylamine replenishment pump.

[0033] It also includes a dimethylamine replenishment pump, the inlet of which is connected to the dimethylamine storage tank, and the outlet is connected to the system from the dimethylamine circulation pump, so as to facilitate the replenishment of dimethylamine in the system.

[0034] A flow regulating valve is provided on the hot water pipe 7 between the shell-side outlet of the propane heater 2 and the shell-side inlet of the intermediate medium vaporizer 3.

[0035] A gas-liquid separator is provided between the outlet of the turbine generator set 4 and the shell-side inlet of the liquefied propane vaporizer 1. The liquid phase outlet of the gas-liquid separator is connected to the inlet of the dimethylamine circulating pump 5 through a return pipe.

[0036] The dimethylamine storage tank is equipped with a pressure balancing pipe at the top, which is connected to the outlet pipe of the turbine generator set 4.

[0037] Propane comes from a cryogenic storage tank and is connected to the tube side of liquefied propane vaporizer 1 via pipeline. The tube side of liquefied propane vaporizer 1 is connected to the tube side of propane heater 2, and then transported to the propane pipeline network. Dimethylamine is pressurized by dimethylamine circulating pump 5 and vaporized in the tube side of intermediate medium vaporizer 3. After that, it goes to turbine generator set 4 to perform turbine work, and then connects to the shell side of liquefied propane vaporizer 1 for condensation.

[0038] Dimethylamine first exchanges heat with liquefied propane at the propane vaporizer 1, where it is condensed into a liquid. It is then pressurized by the dimethylamine circulating pump 5, and then exchanges heat with seawater at the intermediate medium vaporizer 3, where it is vaporized into a gas. This gas then powers the turbine generator set 4 to generate electricity. Finally, it exchanges heat again at the propane vaporizer 1 and is condensed back into a liquid, thus completing the cycle. The key points of this cycle are: first, the dimethylamine must be condensed into a liquid state after heat exchange with the liquefied propane (i.e., before passing through the pump); second, the dimethylamine must be completely vaporized before entering the turbine generator; and third, the propane gas temperature must be 10°C or higher after passing through the propane heater E3. Furthermore, considering the actual operation of the process, a dimethylamine storage tank and a dimethylamine makeup pump are also required.

[0039] Simulation of liquefied propane cold energy power generation process:

[0040] The Aspen Plus software was used to simulate and analyze the cold energy power generation process. A model was built in Aspen Plus, using a low-temperature Rankine cycle with dimethylamine as the circulating medium for power generation. Liquefied propane was used to liquefy the dimethylamine through heat exchange, followed by pressurization via a dimethylamine circulation pump. The dimethylamine was then vaporized through a dimethylamine vaporizer with heat exchange with hot water, and finally, work was done by a turbine expander to complete the cycle. The initial parameters of the power generation process flow are shown in Table 1. The initial parameters of the power generation equipment are shown in Table 2.

[0041] Table 1 Initial parameters of the power generation process flow stream

[0042]

[0043] Table 2 Initial parameters of power generation process equipment

[0044]

[0045] After inputting the initial parameters, select the environmental parameters and calculation method (both using HYSYS parameters and methods), and click Run to obtain the material balance results, as shown in Table 3.

[0046] Table 3 Material Balance Results

[0047]

[0048] In this process, the dimethylamine circulating pump consumes 17.34 kW / h, and the dimethylamine expander consumes -1332.29 kW / h, so the total net energy consumption is -1314.95 kW / h. Assuming a generator efficiency of 0.95, the calculated electricity output is 1248.3 kW·h, and the usage is 150 t / h. Therefore, the power generation per unit mass of liquefied propane is 8.322 kW·h / t. Based on the theoretical cooling capacity per ton of liquefied propane, the calculated cold energy power generation efficiency is 8.4%.

[0049] This invention designs a low-temperature Rankine cycle power generation process. The process uses 150 tons of liquefied propane per hour, and the generator produces 1248.3 kWh of electricity. Dividing the output by the amount of liquefied propane used yields a power generation rate of 8.322 kWh / t per unit mass of liquefied propane. The daily power generation is 29959.2 kWh, and the annual power generation is 1.09 × 10⁷ kWh. Assuming all this electricity is used by the receiving station, and given an electricity price of 0.8 yuan / (kWh), the annual electricity cost savings are 8,748,086.4 yuan. Furthermore, since one ton of liquefied propane contains 355.9 MJ of cooling energy, the power generation efficiency of this designed liquefied propane cold energy power generation process is 8.4%.

[0050] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A power generation device based on the cold energy of a low-temperature propane tank, characterized in that: It includes a liquefied propane vaporizer (1), a propane heater (2), an intermediate medium vaporizer (3), a turbine generator set (4), and a dimethylamine circulating pump (5). The inlet of the liquefied propane vaporizer (1) is connected to the cryogenic storage tank (6), which contains propane. The outlet of the liquefied propane vaporizer (1) is connected to the inlet of the propane heater (2), which is connected to the propane pipeline network. Dimethylamine is connected to the inlet of the intermediate medium vaporizer (3) after passing through the dimethylamine circulation pump (5). The outlet of the intermediate medium vaporizer (3) is connected to the turbine generator. The inlet of group (4) is connected, the outlet of turbine generator set (4) is connected to the shell-side inlet of liquefied propane vaporizer (1), the shell-side outlet of liquefied propane vaporizer (1) is connected to the inlet of dimethylamine circulating pump (5), the shell-side inlet of propane heater (2) is connected to hot water pipe (7), the shell-side outlet of propane heater (2) is connected to the shell-side inlet of intermediate medium vaporizer (3), and the shell-side outlet of intermediate medium vaporizer (3) is connected to hot water return pipe.

2. The power generation device based on the cold energy of a low-temperature propane tank according to claim 1, characterized in that: It also includes a dimethylamine storage tank, which is connected to the inlet of the dimethylamine replenishment pump.

3. The power generation device based on the cold energy of a low-temperature propane tank according to claim 2, characterized in that: It also includes a dimethylamine replenishment pump, the inlet of which is connected to a dimethylamine storage tank, and the outlet of which is connected to a pipeline before the dimethylamine circulation pump.

4. The power generation device based on the cold energy of a low-temperature propane tank according to claim 1, characterized in that: A flow regulating valve is provided on the hot water pipe (7) between the shell-side outlet of the propane heater (2) and the shell-side inlet of the intermediate medium vaporizer (3).

5. The power generation device based on the cold energy of a low-temperature propane tank according to claim 1, characterized in that: A gas-liquid separator is provided between the outlet of the turbine generator set (4) and the shell-side inlet of the liquefied propane vaporizer (1). The liquid phase outlet of the gas-liquid separator is connected to the inlet of the dimethylamine circulating pump (5) through a return pipe.

6. The power generation device based on the cold energy of a low-temperature propane tank according to claim 2, characterized in that: The dimethylamine storage tank is equipped with a pressure balancing pipe and a hand valve at the top. The pressure balancing pipe is connected to the outlet pipe of the turbine generator set (4).

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