High-temperature steam production system and method with internal afterburning

Abstract

The invention provides a high-temperature steam production system and method with internal afterburning, belongs to the technical field of steam production, and can at least partially solve the problems that an existing boiler is long in steam production process, large in high-temperature heating surface requirement, difficult in heating surface arrangement and high in equipment cost. The system comprises an external combustion type steam production system, an internal afterburning type steam temperature increasing system and a steam mixing temperature equalizing section, and has the beneficial effects that water is heated into low-temperature steam through a heat exchange element by utilizing the steam production system such as a boiler, and the internal combustion type steam temperature increasing system is additionally arranged in a steam conveying channel; the steam temperature can be quickly increased in a short process; compared with a full external heat combustion type steam generator, the final increase of the steam temperature is achieved by directly mixing gas generated by internal afterburning and heat with steam, a large number of high-temperature heating surfaces do not need to be arranged, the heat exchange efficiency is high, and the steam generator is suitable for peak regulation operation; and a new way can be provided for storage and utilization of green hydrogen and green ammonia as green electricity.

Description

Technical Field

[0001] This invention belongs to the field of steam production technology, specifically relating to a high-temperature steam production system and method with internal combustion. Background Technology

[0002] In the energy and chemical industries, high-temperature steam is an important working medium. Industrially used high-temperature steam is typically found in various types of steam production equipment, such as steam boilers and nuclear power plant steam generators. Through various heat exchange elements (such as economizers, water-cooled walls, superheaters, and reheaters in boilers, and heat transfer tubes in nuclear power plant steam generators), the heat energy released from fuel combustion and nuclear reactions is transferred to water via heat conduction to form saturated steam, which is then further superheated to form superheated steam, reaching the required temperature. These boilers and steam generators consist of two main parts: the boiler and the furnace. The combustion process takes place outside the heat engine (i.e., the "furnace"), thus classifying them as external combustion engines. Besides external combustion engines like boilers, internal combustion engines such as gas turbines and hydrogen gas turbines can convert combustion energy into mechanical energy.

[0003] However, external combustion engines such as steam boilers are bulky, have high system thermal inertia, and poor peak-shaving performance. If the required steam temperature is very high, directly heating the steam to the required temperature using external combustion engines such as boilers would lengthen the steam flow path, require more high-temperature heating surfaces, and sometimes pose difficulties in arranging the heating surfaces. In addition, the amount of high-temperature materials used is large, resulting in high equipment costs. Meanwhile, internal combustion engines can only use gaseous or liquid fuels, resulting in high fuel costs. Furthermore, due to the high working fluid temperature, the material performance requirements for high-temperature flow components are extremely high, and the technical requirements and costs for operation and maintenance are also very high. Therefore, we propose a high-temperature steam production system and method with internal combustion supplementation. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and to provide a high-temperature steam production system and method with internal combustion.

[0005] The present invention provides a high-temperature steam production system with internal combustion, comprising an external combustion steam production system, an internal combustion steam temperature enhancement system, and a steam mixing and homogenization section; The external combustion steam production system is a boiler or a nuclear power plant steam generator; The internal combustion type steam temperature enhancement system includes a combustion chamber, a fuel input pipe, an oxidant input pipe, a cooling medium input pipe, and a burner. The burner is located in the combustion chamber. The fuel input pipe and the oxidant input pipe are connected to the burner, and the cooling medium input pipe is connected to the combustion chamber.

[0006] Furthermore, the cooling medium input pipe is provided with a branch pipe, which is connected to the fuel input pipe and the oxidant input pipe respectively.

[0007] Specifically, all pipelines of the high-temperature steam production system are equipped with temperature, pressure, and flow measurement and control systems.

[0008] Another aspect of the present invention provides a method for producing high-temperature steam with internal combustion, the method being implemented using the aforementioned high-temperature steam production system with internal combustion, and comprising the following steps: A1: The external combustion steam production system 1 heats water or steam into superheated steam S1 at a temperature of T1; A2: Fuel and oxidant enter the burner through the fuel input pipe and the oxidant input pipe in the internal combustion type steam temperature rise system 2, and are burned to release heat, heating the combustion products and the cooling medium entering the combustion chamber through the cooling medium input pipe to a mixed working fluid S2 at a temperature T2; A3: Superheated steam S1 and mixed working fluid S2 enter the steam mixing and temperature equalization section 3 through the pipeline and mix evenly to form a mixed working fluid S3 with superheated steam as the main component at a temperature of T3, which then enters the steam turbine or other downstream steam-using equipment.

[0009] Preferably, in step A2, the fuel is one or more of hydrogen, natural gas, ammonia, and ammonia water.

[0010] Specifically, in step A2, the oxidant is either oxygen or air, and the cooling medium is either cooling water or cooling steam.

[0011] Furthermore, in step A2, part or all of the cooling medium is mixed with the fuel and oxidant in the fuel input pipe and oxidant input pipe respectively through the branch pipe of the cooling medium input pipe to reduce the temperature of the combustion flame.

[0012] Furthermore, the high-temperature steam production method for in-zone combustion controls the combustion flame temperature above the ignition point of the fuel and below 1000°C by controlling the temperature and flow rate of the cooling medium.

[0013] Furthermore, in step A3, the temperature T3 of the mixed working medium S3 is regulated by the flow rate and temperature of the superheated steam S1 and the mixed working medium S2.

[0014] Specifically, in step A3, the temperature T3 of the mixed working fluid S3 is no more than 100°C higher than the temperature T1 of the superheated steam S1.

[0015] The beneficial effects of this invention are as follows: Steam production systems such as boilers heat water or steam into lower-temperature steam. An internal combustion-type steam temperature enhancement system is added to the steam transmission channel to achieve a short-process, rapid increase in steam temperature. The steam generator system provides most of the heat required to raise the steam temperature from water to superheated steam (T1) through heat exchange elements, thus providing the "quantity" of steam production. The steam temperature enhancement system provides a small portion of heat through direct mixing, rapidly raising the steam temperature to T2, thus improving the "quality" of the steam. Compared to fully externally heated steam generators like boilers, this system achieves the final temperature increase by directly mixing the gas and heat generated by internal combustion with the steam. This eliminates the need for a large number of high-temperature heating surfaces, resulting in high heat exchange efficiency, less use of high-grade high-temperature materials, and faster steam temperature regulation, making it suitable for peak-shaving operations. Furthermore, compared to single internal combustion engines like gas turbines, most of the required heat can be obtained from relatively inexpensive fuels such as coal, biomass, and coal gangue, while gaseous fuels like natural gas and hydrogen are only used for a small amount of heat required for the final temperature increase, resulting in low fuel costs. Furthermore, if surplus electricity, especially green electricity from photovoltaic and wind power, is used to produce green hydrogen and green ammonia as fuel, this technology can also serve as a new technical path for the storage and consumption of new energy electricity. Compared with the technology of blending hydrogen and ammonia fuel in boilers, the technology adopted in this invention has higher thermal efficiency and can suppress the formation of nitrogen oxides by adjusting the combustion temperature. In addition, some existing boilers can achieve the increase of steam temperature with only simple modifications. Attached Figure Description

[0016] Figure 1 This is a connection diagram of a high-temperature steam production system with internal combustion according to a specific embodiment of the present invention. Figure 2 This is a flowchart illustrating the steps of a high-temperature steam production method with internal combustion, according to a specific embodiment of the present invention.

[0017] The system includes: 1. External combustion steam production system; 2. Internal combustion steam temperature enhancement system; 2-1. Combustion chamber; 2-2. Fuel input pipe; 2-3. Oxidant input pipe; 2-4. Cooling medium input pipe; 2-5. Burner; 3. Steam mixing and equalization section. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] like Figure 1As shown in the figure, a high-temperature steam production system with internal combustion provided by a specific embodiment of the present invention includes an external combustion steam production system 1, an internal combustion steam temperature enhancement system 2, and a steam mixing and equalization section 3; wherein, the external combustion steam production system 1 is a boiler or a nuclear power plant steam generator; the internal combustion steam temperature enhancement system 2 includes a combustion chamber 2-1, a fuel input pipe 2-2, an oxidant input pipe 2-3, a cooling medium input pipe 2-4, and a burner 2-5, the burner is installed in the combustion chamber, the fuel input pipe and the oxidant input pipe are connected to the burner, and the cooling medium input pipe is connected to the combustion chamber.

[0020] Specifically, the external combustion steam production system continuously generates and outputs low-temperature steam during operation, providing most of the heat for high-temperature steam production.

[0021] Furthermore, the internal combustion steam temperature enhancement system 2 increases the steam temperature to achieve internal combustion heating, thereby improving the overall thermal efficiency and generating a high-temperature working fluid for subsequent mixing.

[0022] Furthermore, the steam mixing and temperature equalization section 3 is used to mix the low-temperature steam produced by the external combustion steam production system with the high-temperature working fluid produced by the internal combustion steam temperature enhancement system to form a mixed working fluid mainly composed of the required high-temperature superheated steam.

[0023] Based on the above basic implementation method, the cooling medium input pipe 2-4 is provided with a branch pipe, which is connected to the fuel input pipe 2-2 and the oxidant input pipe 2-3 respectively.

[0024] Specifically, fuel inlet pipe 2-2 ensures sufficient fuel supply for the combustion process. Oxidant inlet pipe 2-3 ensures sufficient oxidant participation in the combustion process, supporting efficient combustion and generating combustion products. By controlling the oxidant flow rate through the piping, combustion efficiency can be optimized and incomplete combustion reduced.

[0025] In one specific implementation, all pipelines of the high-temperature steam production system are equipped with temperature, pressure, and flow measurement and control systems.

[0026] Another aspect of the present invention provides a method for producing high-temperature steam with internal combustion, the method being implemented using a high-temperature steam production system with internal combustion, and comprising the following steps: A1: Water or steam is heated into superheated steam S1 at a temperature of T1 by an external combustion steam production system 1; A2: Fuel and oxidant enter the burner 2-5 through the fuel input pipe 2-2 and oxidant input pipe 2-3 in the internal combustion type steam temperature rise system 2, and are burned to release heat, heating the combustion products and the cooling medium entering the combustion chamber 2-1 through the cooling medium input pipe 2-4 to a mixed working fluid S2 at a temperature T2; A3: Superheated steam S1 and mixed working medium S2 enter the steam mixing and temperature equalization section 3 through the pipeline and mix evenly to form a mixed working medium S3 with superheated steam as the main component at a temperature of T3, which then enters the steam turbine or other downstream steam-using equipment.

[0027] Furthermore, in step A2, the fuel in fuel input pipe 2-2 is one or more of hydrogen, natural gas, ammonia, and ammonia water.

[0028] In this embodiment, green hydrogen and green ammonia produced by green electricity such as wind power and solar power in the system can serve as a new technical path for the storage and consumption of new energy power, significantly reducing the carbon footprint; using hydrogen has a high calorific value and the combustion products contain only water, resulting in low content of other gases in the final high-temperature steam. In another specific embodiment, in step A2, the oxidant in the oxidant inlet pipes 2-3 is either air or oxygen.

[0029] Specifically, using air in the system simplifies equipment design and reduces operating costs; using oxygen reduces impurity gases such as nitrogen in combustion products.

[0030] In one specific implementation, in step A2, the working medium transported by the cooling input pipes 2-4 is cooling steam or cooling water. Depending on the pressure and temperature requirements, the cooling steam or cooling water comes from an appropriate part of the external combustion steam production system, such as the feedwater pipe, the reheat steam cold section pipe, etc.

[0031] In another specific embodiment, in step A2, part or all of the cooling medium is mixed with the fuel and oxidant in the fuel input pipe 2-2 and oxidant input pipe 2-3 respectively through the branch pipe of the cooling medium input pipe 2-4 to reduce the temperature of the combustion flame.

[0032] Furthermore, the high-temperature steam production method for in-belt combustion controls the combustion flame temperature above the ignition point of the fuel and below 1000°C by controlling the temperature and flow rate of the cooling medium; in step A3, the temperature T3 of the mixed working medium S3 is regulated by the flow rate and temperature of the superheated steam S1 and the mixed working medium S2; in step A3, the temperature T3 of the mixed working medium S3 is no more than 100°C higher than the temperature T1 of the superheated steam S1.

[0033] like Figure 1 As shown, in a specific embodiment, S1 is superheated steam at temperature T1 produced by steam production system 1; S2 is a mixture of steam and combustion products at temperature T2 generated by steam temperature enhancement system 2; and S3 is a working fluid mainly composed of superheated steam at temperature T3, formed by uniformly mixing S1 and S2 in steam mixing and temperature equalization section 3.

[0034] In this embodiment, a coal-fired boiler (90% thermal efficiency) serves as steam production system 1, heating feedwater at 250°C into superheated steam S1 with steam parameters of 540°C and 17MPa. In steam temperature enhancement system 2, hydrogen and oxygen are used as fuel and oxidant, respectively, to generate high-temperature steam, which is then mixed with the preceding superheated steam S1 to produce 1000 tons / hour of superheated steam S3 at 600°C and 17MPa. This requires approximately 110.23 tons / hour of 5500 kcal / kg thermal coal, 1.45 tons / hour of hydrogen, and 11.62 tons / hour of oxygen, providing 2.538 × 10⁻⁶ heat. 9 kJ, 0.208×10 9 kJ, total energy consumed 2.746×10 9 The hydrogen gas accounts for 7.6% of the heat generated. In comparison, using a coal-fired boiler (90% thermal efficiency) to directly heat 250℃ feedwater into 1000 tons of superheated steam at 600℃ and 17MPa requires 119.65 tons of thermal coal and provides 2.755 × 10⁻⁶ kJ of heat. 9 kJ.

[0035] In another specific embodiment, a coal-fired boiler (90% thermal efficiency) serves as steam production system 1, heating feedwater at 300°C into superheated steam S1 with steam parameters of 600°C and 35MPa. In steam temperature enhancement system 2, hydrogen and oxygen are burned as fuel and oxidant, respectively, to generate high-temperature steam, which is then mixed with the preceding superheated steam S1 to obtain 2800 tons / hour of superheated steam S3 at 650°C and 35MPa. This requires approximately 276.36 tons / hour of 5500 kcal / kg thermal coal, 4 tons / hour of hydrogen, and 31.92 tons / hour of oxygen, providing a total heat output of 6.364 × 10⁻⁶ tons / hour. 9 kJ, 0.5704×10 9 kJ, total energy consumed 6.934×10 9 The hydrogen gas accounts for 8.2% of the heat generated. In comparison, using a coal-fired boiler (90% thermal efficiency) to directly heat 300℃ feedwater into 2800 tons of superheated steam at 650℃ / 35MPa requires 301.84 tons of thermal coal and provides 6.95 × 10⁻⁶ kJ of heat. 9 kJ.

[0036] In this embodiment, 250°C / 17MPa cooling water is mixed with fuel and oxidant in fuel input pipe 2-2 and oxidant input pipe 2-3 respectively through a branch pipe of cooling medium input pipe 2-4. When the mass ratio of cooling water to hydrogen is 36:1 (the ratio of cooling water to water generated by hydrogen combustion is 4:1), the temperature of the combustion flame is about 798°C. In contrast, without cooling steam or cooling water, the combustion temperature of hydrogen in oxygen can reach over 2800°C, which places high demands on the high-temperature performance of the combustion chamber material.

[0037] To help better understand the present invention, a more comprehensive and specific embodiment of the present invention is described. In this embodiment, the present invention provides a high-temperature steam production system with internal combustion, including an external combustion steam production system 1, an internal combustion steam temperature enhancement system 2, and a steam mixing and equalization section 3. Among them, the external combustion type steam production system 1 is a boiler or nuclear power plant steam generator; the internal combustion type steam temperature enhancement system 2 includes a combustion chamber 2-1, a fuel input pipe 2-2, an oxidant input pipe 2-3, a cooling medium input pipe 2-4, and a burner 2-5. The burner is installed in the combustion chamber, the fuel input pipe and the oxidant input pipe are connected to the burner, and the cooling medium input pipe is connected to the combustion chamber.

[0038] In this embodiment, the cooling medium input pipe 2-4 is provided with a branch pipe, which is connected to the fuel input pipe 2-2 and the oxidant input pipe 2-3 respectively; all pipelines of the high-temperature steam production system are equipped with temperature, pressure and flow measurement and control systems.

[0039] Furthermore, another aspect of the present invention provides a method for producing high-temperature steam with internal combustion, the method being implemented using the aforementioned high-temperature steam production system with internal combustion, and comprising the following steps: A1: Water is heated into superheated steam S1 at a temperature of T1 by an external combustion steam production system 1; A2: Fuel and oxidant enter the burner 2-5 through the fuel input pipe 2-2 and oxidant input pipe 2-3 in the internal combustion type steam temperature rise system 2, and are burned to release heat, heating the combustion products and the cooling medium entering the combustion chamber 2-1 through the cooling medium input pipe 2-4 to a mixed working fluid S2 at a temperature T2; A3: Superheated steam S1 and mixed working fluid S2 enter the steam mixing and homogenization section 3 through pipelines and mix evenly to form mixed working fluid S3, mainly superheated steam at temperature T3, which then enters the steam turbine or other downstream steam-using equipment; in step A2, the fuel is one or more of hydrogen, natural gas, ammonia, and ammonia water; in step A2, the oxidant is one of oxygen or air, and the cooling medium is one of cooling water or cooling steam; in step A2, part or all of the cooling medium is supplied through the branch pipes of cooling medium inlet pipes 2-4 respectively. The fuel and oxidant in the fuel inlet pipe 2-2 and the oxidant inlet pipe 2-3 are mixed to reduce the temperature of the combustion flame. The high-temperature steam production method with in-zone combustion controls the combustion flame temperature above the ignition point of the fuel used but below 1000°C by controlling the temperature and flow rate of the cooling medium. In step A3, the temperature T3 of the mixed working medium S3 is regulated by the flow rate and temperature of the superheated steam S1 and the mixed working medium S2. In step A3, the temperature T3 of the mixed working medium S3 is no more than 100°C higher than the temperature T1 of the superheated steam S1.

[0040] In summary, the embodiments disclosed herein have at least the following technical effects: Reduce boiler size and the amount of high-temperature heating surfaces and materials used: By adding an internal combustion steam temperature enhancement system to the steam transmission channel, a short-process and rapid increase in steam temperature can be achieved. Compared with a fully external combustion steam generator, since the final increase in steam temperature is achieved by directly mixing the gas and heat generated by internal combustion with the steam, it is not necessary to arrange a large number of high-temperature heating surfaces, reducing the amount of high-temperature materials used and resulting in high heat exchange efficiency.

[0041] Achieve flexible steam temperature increase: By setting up a combustion chamber 2-1, a burner 2-5 and a fuel / oxidant input pipe in the steam temperature enhancement system 2, the steam temperature can be flexibly increased based on low-temperature steam to meet the requirements of high-temperature steam conditions. Ensure steam temperature stability: A steam mixing and temperature equalization section is set up to fully mix the reference steam with the first mixing working fluid, so that the output steam temperature is more uniform and the fluctuation of steam quality caused by single high-temperature combustion is avoided. Improve system security: Cooling steam or cooling water is introduced through cooling input pipe 2-4 to reduce the temperature of the working fluid during combustion, thus avoiding damage to the combustion chamber and mixing homogenization section components caused by excessively high temperatures. Suitable for a variety of fuels and oxidizers: The system supports a variety of fuels, including hydrogen, natural gas, ammonia, and ammonia water, as well as air or oxygen as an oxidant. It has good adaptability and flexibility. Using green hydrogen and green ammonia can reduce the consumption of fossil fuels and reduce carbon dioxide emissions.

[0042] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A high-temperature steam production system with internal combustion enhancement, characterized in that, It includes an external combustion steam production system 1, an internal combustion steam temperature enhancement system 2, and a steam mixing and equalization section 3; Wherein, the external combustion steam production system 1 is a boiler or a nuclear power plant steam generator; The internal combustion type steam temperature enhancement system 2 includes a combustion chamber 2-1, a fuel input pipe 2-2, an oxidant input pipe 2-3, a cooling medium input pipe 2-4, and a burner 2-5. The burner is disposed in the combustion chamber. The fuel input pipe and the oxidant input pipe are connected to the burner, and the cooling medium input pipe is connected to the combustion chamber.

2. The high-temperature steam production system with internal combustion as described in claim 1, characterized in that, The cooling medium input pipe 2-4 is provided with a branch pipe, which is connected to the fuel input pipe 2-2 and the oxidant input pipe 2-3 respectively.

3. The high-temperature steam production system with internal combustion as described in claim 2, characterized in that, All pipelines in the high-temperature steam production system are equipped with temperature, pressure, and flow measurement and control systems.

4. A method for producing high-temperature steam with internal combustion, characterized in that, The method is implemented using a high-temperature steam production system with internal combustion according to any one of claims 1 to 3, and includes the following steps: A1: The external combustion steam production system 1 heats water or steam into superheated steam S1 at a temperature of T1; A2: Fuel and oxidant enter the burner 2-5 through the fuel input pipe 2-2 and the oxidant input pipe 2-3 in the internal combustion type steam temperature rise system 2, and are burned to release heat, heating the combustion products and the cooling medium entering the combustion chamber 2-1 through the cooling medium input pipe 2-4 to a mixed working fluid S2 at a temperature T2; A3: Superheated steam S1 and mixed working fluid S2 enter the steam mixing and temperature equalization section 3 through the pipeline and mix evenly to form a mixed working fluid S3 with superheated steam as the main component at a temperature of T3, which then enters the steam turbine or other downstream steam-using equipment.

5. The high-temperature steam production method with internal combustion according to claim 4, characterized in that, In step A2, the fuel is one or more of hydrogen, natural gas, ammonia, and ammonia water.

6. The high-temperature steam production method with internal combustion according to claim 4, characterized in that, In step A2, the oxidant is either oxygen or air, and the cooling medium is either cooling water or cooling steam.

7. The high-temperature steam production method with internal combustion according to claim 4, characterized in that, In step A2, part or all of the cooling medium is mixed with the fuel and oxidant in the fuel input pipe 2-2 and oxidant input pipe 2-3 through the branch pipe of the cooling medium input pipe 2-4, respectively, to reduce the temperature of the combustion flame.

8. The high-temperature steam production method with internal combustion according to claim 4, characterized in that, This high-temperature steam production method with in-belt combustion controls the combustion flame temperature above the ignition point of the fuel and below 1000°C by controlling the temperature and flow rate of the cooling medium.

9. The high-temperature steam production system with internal combustion according to claim 4, characterized in that, In step A3, the temperature T3 of the mixed working medium S3 is regulated by the flow rate and temperature of the superheated steam S1 and the mixed working medium S2.

10. The high-temperature steam production system with internal combustion according to claim 4, characterized in that, In step A3, the temperature T3 of the mixed working fluid S3 is no more than 100°C higher than the temperature T1 of the superheated steam S1.

Images