Comprehensive utilization system of blast furnace slag flushing water and flue gas waste heat from gas generator sets

Abstract

The present application discloses a comprehensive utilization system for blast furnace slag water and flue gas waste heat from gas generator sets. The system includes condensate, a slag water-condensate heat exchanger, a slag water circulating water pool, a low-temperature economizer, a low-pressure heater, a dust collector, an induced draft fan, a gate valve, a condensate booster pump, a check valve, an electric gate valve, and a slag water booster pump. The main condensate route passes through various levels of low-pressure heaters, and the other route passes through the slag water-condensate heat exchanger and the low-temperature economizer to the low-pressure heater. The slag water-condensate heat exchanger and the slag water circulating water pool are connected by pipes; the dust collector, the low-temperature economizer, and the induced draft fan are connected by pipes. The present application heats the condensate of the gas generator set in stages according to the temperature of the slag water and the flue gas, so as to achieve the purpose of waste heat recovery and utilization, which is beneficial to the technical effect of energy conservation and environmental protection.

Description

Technical Field

[0001] The present application relates to the technical field of coal gas power generation, and in particular to a system for comprehensive utilization of blast furnace slag flushing water and flue gas waste heat from coal gas power generation units. Background Art

[0002] During the ironmaking process, blast furnaces produce high-temperature slag at around 1500°C. The primary slag treatment process involves water quenching, which produces a large amount of slag-flushing water. This water removes approximately 8% of the energy consumed in ironmaking, equivalent to 21kg of standard coal per ton of iron. my country is a major producer of steel, and with an annual output of 500 million tons, this water-flushing heat is equivalent to 10 million tons of standard coal. However, the circulating water pool used for slag-flushing, at approximately 80°C, represents a low-temperature waste heat source with limited utilization options. Consequently, much of this heat is wasted, necessitating the urgent need to explore more ways to utilize this waste heat.

[0003] The steelmaking process also produces a large amount of blast furnace gas. Currently, most steel mills are fully utilizing this energy by building clean energy power generation projects to use the surplus blast furnace gas for power generation. However, the exhaust temperature of most blast furnace gas boilers is currently above 140°C, which is still relatively high compared to large coal-fired units. This flue gas waste heat still has room for further recovery and utilization. Therefore, a comprehensive system for utilizing blast furnace slag flushing water and flue gas waste heat from gas-fired generators has become a key technical issue in this field. Summary of the Invention

[0004] In view of this, the present application provides a comprehensive utilization system of blast furnace slag flushing water and flue gas waste heat from gas generator sets, which can improve the thermal efficiency of the unit's power generation and achieve the purpose of waste heat recovery and utilization.

[0005] The present application provides a comprehensive utilization system of blast furnace slag flushing water and flue gas waste heat from a gas-fired generator set, comprising a slag flushing water-condensate heat exchanger, an economizer, a first heater, a second heater, and a booster pipeline assembly;

[0006] The water inlet of the second heater is used to allow condensate to flow in, and the water outlet of the second heater is connected to the water inlet of the first heater to form a condensate main path;

[0007] The slag flushing water-condensate heat exchanger has two water inlets for introducing slag flushing water and condensate respectively, and the water outlet of the slag flushing water-condensate heat exchanger is connected to the water inlet of the boosting pipeline assembly;

[0008] The water outlet of the boosting pipeline assembly is connected to the water inlet of the second heater to form a first condensate branch;

[0009] The water outlet of the boost pipeline assembly is connected to the water inlet of the first heater through the economizer to form a second condensate branch, and the air inlet of the economizer is used to allow flue gas to enter; when the temperature of the flue gas is low, the second condensate branch is configured to be cut off, and when the temperature of the flue gas is high, the second condensate branch is configured to be opened.

[0010] Optionally, the condensate main path further includes a fourth heater and a third heater which are connected in sequence according to the flow direction of the heated condensate.

[0011] Optionally, the boost pipeline assembly includes a boost pipeline with an inlet connected to the slag flushing water-condensate heat exchanger and an outlet connected to the second heater. The boost pipeline includes a gate valve a, a condensate boost pump a, a check valve a, and an electric gate valve a in sequence according to the flow direction of the heated condensate.

[0012] Optionally, the boost pipeline assembly includes a spare boost pipeline whose water inlet is connected to the slag flushing water-condensate heat exchanger and whose water outlet is connected to the second heater. The spare boost pipeline includes a gate valve b, a condensate boost pump b, a check valve b and an electric gate valve b in sequence according to the flow direction of the heated condensate.

[0013] Optionally, the water inlet of the slag flushing water-condensate heat exchanger for introducing slag flushing water is connected to a slag flushing water supply pipeline, and the slag flushing water supply pipeline is connected to the gate valve c, slag flushing water booster pump a, check valve c, and electric gate valve c in sequence according to the flow direction pointing to the slag flushing water-condensate heat exchanger.

[0014] Optionally, the water inlet of the slag flushing water-condensate heat exchanger for introducing slag flushing water is connected to a spare slag flushing water supply pipeline, and the spare slag flushing water supply pipeline is connected to the gate valve d, slag flushing water booster pump b, check valve d and electric gate valve d in sequence according to the flow direction pointing to the slag flushing water-condensate heat exchanger.

[0015] Optionally, the air inlet of the economizer is connected to a dust collector.

[0016] Optionally, the air outlet of the economizer is connected to an induced draft fan.

[0017] The above-provided blast furnace slag flushing water and gas-fired generator set flue gas waste heat comprehensive utilization system heats the condensate of the gas-fired generator set in stages according to the temperature of the slag flushing water and the flue gas. Part of the condensate is heated from an initial temperature, such as 41°C, to a first temperature, such as 70°C, by the slag flushing water, and then the condensate is heated from the first temperature to a predetermined temperature, such as 128°C, by the flue gas waste heat. The heat is utilized in the gas-fired generator set through the condensate, thereby improving the thermal efficiency of the unit's power generation and achieving the purpose of waste heat recovery and utilization. It has important guiding significance for steel enterprises to respond to the "dual carbon policy" and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0019] Figure 1 This is a structural schematic diagram of the comprehensive utilization system of blast furnace slag flushing water and gas generator set flue gas waste heat provided in the embodiment of the present application.

[0020] The components in the figure are identified as follows:

[0021] 1—Condensate; 2—Slag flushing water-condensate heat exchanger; 3—Slag flushing water circulation pool;

[0022] 4—Economizer; 5—First heater; 6—Second heater; 7—Third heater; 8—Fourth heater; 9—Dust collector; 10—Induced draft fan;

[0023] 21—gate valve a; 22—condensate booster pump a; 23—check valve a; 24—electric gate valve a;

[0024] 25—gate valve b; 26—condensate booster pump b; 27—check valve b; 28—electric gate valve b;

[0025] 31—gate valve c; 32—slag flushing water booster pump a; 33—check valve c; 34—electric gate valve c;

[0026] 35—Gate valve d; 36—Slag flushing water booster pump b; 37—Check valve d; 38—Electric gate valve d; 41—Electric gate valve e; 42—Electric gate valve f; 61—Electric gate valve g. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0028] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0029] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0030] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0031] The present application is a comprehensive utilization system of blast furnace slag flushing water and flue gas waste heat from a gas-fired generator set, comprising condensate 1, a slag flushing water-condensate heat exchanger 2, a slag flushing water circulating water pool 3, an economizer 4, a first heater 5, a second heater 6, a third heater 7, a fourth heater 8, a dust collector 9, an induced draft fan 10, a gate valve a21, a condensate booster pump a22, a check valve a23, an electric gate valve a24, a gate valve b25, a condensate booster pump b26, a check valve b27, an electric gate valve b28, a gate valve c31, a slag flushing water booster pump a32, a check valve c33, an electric gate valve c34, a gate valve d35, a slag flushing water booster pump b36, a check valve d37, an electric gate valve d38, an electric gate valve e41, an electric gate valve f42 and an electric gate valve g61.

[0032] like Figure 1 As shown, the condensate 1, the fourth heater 8, the third heater 7, the second heater 6 and the first heater 5 are connected in sequence through pipes to form a condensate main path. In the gas generator set, this part is used to heat the condensate 1, and most of the condensate 1 passes through this condensate main path.

[0033] like Figure 1As shown, a portion of condensate 1 (temperature approximately 41°C) is drawn from the slag flushing water-condensate heat exchanger 2 for heating. The heated condensate (temperature approximately 70°C) then passes through gate valve a21, condensate booster pump a22, check valve a23, and electric gate valve a24, thereby boosting its pressure. The pipeline formed by gate valve a21, condensate booster pump a22, check valve a23, and electric gate valve a24 serves as the backup condensate boosting pipeline. This pipeline can be used to boost the condensate pressure in the event of a malfunction of condensate booster pump a22. The boosted condensate can then flow through electric gate valve g61 to the second heater 6, where it mixes with the main condensate line (temperature approximately 97°C). This forms the first condensate branch. Alternatively, it can flow through electric gate valve e41, economizer 4, and electric gate valve f42 to the first heater 5, forming the second condensate branch. When the flue gas temperature in the economizer 4 is high enough to heat the condensate, the second condensate branch is opened and the first condensate branch is closed. At this time, the condensate is heated by the economizer 4 (temperature is about 128°C) and goes to the first heater 5 with a higher heating temperature to mix with the condensate main line (temperature is about 123°C); when the flue gas temperature in the economizer 4 is low and does not meet the conditions for heating the condensate, the first condensate branch is opened and the second condensate branch is closed. At this time, the condensate goes to the second heater 6 with a lower heating temperature.

[0034] like Figure 1 As shown, the dust collector 9, economizer 4 and induced draft fan 10 are connected in sequence through pipes to form a flue gas heat exchange pipeline. When the flue gas enters the economizer 4 with a high temperature, it can be used to heat the condensate in the second condensate branch; when the flue gas enters the economizer 4 with a low temperature, in order to avoid low-temperature corrosion, the second condensate branch can be omitted.

[0035] like Figure 1 As shown, the slag flushing water circulation pool 3, the gate valve c31, the slag flushing water booster pump a32, the check valve c33, the electric gate valve c34 and the slag flushing water-condensate heat exchanger 2 are connected in sequence through pipelines to form a slag flushing water supply pipeline, and the slag flushing water (temperature is about 80°C) is sent into the slag flushing water-condensate heat exchanger 2 to heat the condensate; the gate valve d35, the slag flushing water booster pump b36, the check valve d37 and the electric gate valve d38 are connected in sequence through pipelines to form a slag flushing water standby supply pipeline, and the slag flushing water supply pipeline and the slag flushing water standby supply pipeline are connected in parallel. When the slag flushing water booster pump b36 fails, the slag flushing water standby supply pipeline can be put into use. The slag flushing water-condensate heat exchanger 2 and the slag flushing water circulating water pool 3 are directly connected by a pipe to form a slag flushing water return pipeline, which is used to recover the low-temperature slag flushing water (temperature of about 50°C) after heating the condensate water. The cooled slag flushing water is continued to be used for slag cooling.

[0036] In a gas-fired generator set, extracting high-temperature, high-pressure steam from each stage of the steam turbine to heat condensate passing through the fourth heater 8, third heater 7, second heater 6, and first heater 5 results in a waste of high-quality energy. By utilizing the temperatures of the slag-flushing water and flue gas to heat the condensate in the gas-fired generator set in stages, the amount of steam extracted from each stage of the steam turbine can be reduced, increasing the turbine's work capacity and improving the gas-fired generator set's power generation efficiency. Furthermore, this system fully utilizes the waste heat from the slag-flushing water and flue gas, reducing heat loss.

[0037] To sum up, this application heats the condensate of the gas-fired generator set in stages according to the temperature of the slag-flushing water and the flue gas. Part of the condensate is heated from 41°C to 70°C by the slag-flushing water, and then the condensate is heated from 70°C to 128°C by the waste heat of the flue gas. The heat is utilized in the gas-fired generator set through the condensate, thereby improving the thermal efficiency of the unit's power generation and achieving the purpose of waste heat recovery and utilization. It has important guiding significance for steel enterprises to respond to the "dual carbon policy" and environmental protection.

[0038] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

Claims

1. A comprehensive utilization system of blast furnace slag flushing water and flue gas waste heat from gas generator sets, characterized in that: It comprises a slag flushing water-condensate heat exchanger (2), a coal economizer (4), a first heater (5), a second heater (6), and a booster pipeline assembly; The water inlet of the second heater (6) is used to allow condensed water to flow in, and the water outlet of the second heater (6) is connected to the water inlet of the first heater (5) to form a condensed water main path; The slag flushing water-condensate heat exchanger (2) has two water inlets for introducing slag flushing water and condensate respectively, and the water outlet of the slag flushing water-condensate heat exchanger (2) is connected to the water inlet of the boosting pipeline assembly; The water outlet of the boost pipeline assembly is connected to the water inlet of the second heater (6) to form a first condensate branch; The water outlet of the boosting pipeline assembly is connected to the water inlet of the first heater (5) via the economizer (4) to form a second condensate branch, and the air inlet of the economizer (4) is used to allow flue gas to enter; when the temperature of the flue gas is low, the second condensate branch is configured to be cut off, and when the temperature of the flue gas is high, the second condensate branch is configured to be opened; The boost pipeline assembly includes a boost pipeline with a water inlet connected to a slag flushing water-condensate heat exchanger (2) and a water outlet connected to a second heater (6), and the boost pipeline includes a gate valve a (21), a condensate boost pump a (22), a check valve a (23), and an electric gate valve a (24) in sequence according to the flow direction of the heated condensate; The boosting pipeline assembly comprises a spare boosting pipeline having a water inlet connected to a slag flushing water-condensate heat exchanger (2) and a water outlet connected to a second heater (6). The spare boosting pipeline comprises a gate valve b (25), a condensate boosting pump b (26), a check valve b (27) and an electric gate valve b (28) in sequence according to the flow direction of the heated condensate.

2. The system for comprehensive utilization of blast furnace slag flushing water and flue gas waste heat from gas generator sets according to claim 1 is characterized in that: The condensate main path also includes a fourth heater (8) and a third heater (7) which are connected in sequence according to the flow direction of the heated condensate.

3. The system for comprehensive utilization of blast furnace slag flushing water and flue gas waste heat from gas generator sets according to claim 1 is characterized in that: The water inlet of the slag flushing water-condensate heat exchanger (2) for introducing slag flushing water is connected to a slag flushing water supply pipeline, and the slag flushing water supply pipeline is connected to a gate valve c (31), a slag flushing water booster pump a (32), a check valve c (33), and an electric gate valve c (34) in sequence according to the flow direction pointing to the slag flushing water-condensate heat exchanger (2).

4. The system for comprehensive utilization of blast furnace slag flushing water and flue gas waste heat from gas generator sets according to claim 1 is characterized in that: The water inlet of the slag flushing water-condensate heat exchanger (2) for introducing slag flushing water is connected to a slag flushing water standby water supply pipeline, and the slag flushing water standby water supply pipeline is connected to a gate valve d (35), a slag flushing water booster pump b (36), a check valve d (37) and an electric gate valve d (38) in sequence according to the flow direction pointing to the slag flushing water-condensate heat exchanger (2).

5. The system for comprehensive utilization of blast furnace slag flushing water and flue gas waste heat from gas generator sets according to claim 1 is characterized in that: The air inlet of the economizer (4) is connected to a dust collector (9).

6. The system for comprehensive utilization of blast furnace slag flushing water and flue gas waste heat from gas generator sets according to claim 1, characterized in that: The air outlet of the economizer (4) is connected to an induced draft fan (10).

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