Air compressor waste heat and waste nitrogen cooling capacity recovery energy-saving system

Abstract

The utility model provides an air compressor waste heat and waste nitrogen cooling capacity recovery energy-saving system, and relates to the technical field of air separation nitrogen generation. A heater; a purifier; an air compressor cylinder; a circulating heat exchange tube; and a heat exchanger; wherein the waste nitrogen input pipe, the heater and the purifier are sequentially connected, and waste nitrogen in the waste nitrogen input pipe firstly passes through the heat exchanger and exchanges heat with the circulating heat exchange pipe before entering the heater; and a heat exchange medium in the circulating heat exchange pipe circularly passes through the air compressor cylinder and the heat exchanger. According to the system, the waste heat of the air compressor and the cooling capacity of the waste nitrogen are comprehensively utilized, and the bidirectional complementary energy-saving effect is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of air separation nitrogen production, in particular to an energy-saving system for recovering waste heat of an air compressor and cold capacity of dirty nitrogen gas. Background Art

[0002] The air compressor of the current mainstream air separation nitrogen production device uses circulating water to cool the cylinder. In hot summer weather, the operating temperature of the air compressor is too high, and an axial flow fan needs to be added to physically blow air to cool the cylinder, which increases the power consumption of the air compressor and indirectly reduces the operating efficiency of the air compressor.

[0003] The purifier of the air separation unit needs to switch between the operation cycle and the regeneration cycle. During the regeneration cycle, the regeneration gas used (the regeneration gas is contaminated nitrogen gas, and the temperature of contaminated nitrogen gas is only 0~10℃) needs to be heated to 180℃ by an electric heater, which consumes a lot of electricity. In addition, the conventional air separation nitrogen production system only uses a small part of the contaminated nitrogen gas for purifier regeneration, and the cooling capacity of the contaminated nitrogen gas is not fully utilized.

[0004] It can be seen from the above content that the cooling of the air compressor cylinder and the regeneration of the purifier currently have the problem of high overall system energy consumption. Utility Model Content

[0005] In view of the above situation, the utility model provides an air compressor waste heat and contaminated nitrogen gas cooling capacity recovery energy saving system, which aims to solve the current technical problems of high system comprehensive energy consumption in cooling of air compressor cylinders and regeneration of purifiers.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] The utility model provides an energy-saving system for recovering waste heat from air compressor and cold capacity of polluted nitrogen gas, comprising:

[0008] Dirty nitrogen gas inlet pipe;

[0009] Heater;

[0010] Purifier;

[0011] Air compressor cylinder;

[0012] Circulation heat exchange tubes; and

[0013] Heat exchanger;

[0014] Among them, the dirty nitrogen gas input pipe, the heater and the purifier are connected in sequence. Before entering the heater, the dirty nitrogen gas in the dirty nitrogen gas input pipe first passes through the heat exchanger and exchanges heat with the circulating heat exchange pipe; the heat exchange medium in the circulating heat exchange pipe circulates through the air compressor cylinder and the heat exchanger.

[0015] In some embodiments of the utility model, a pressure stabilizing tank and a pressure stabilizing pump are also provided on the path of the circulating heat exchange tube; the heat exchange medium in the circulating heat exchange tube first flows through the pressure stabilizing tank and the pressure stabilizing pump, and then passes through the heat exchanger.

[0016] In some embodiments of the present invention, the pressure-stabilizing pump is a variable frequency pump.

[0017] In some embodiments of the utility model, a remote thermometer is provided on the pressure regulating tank, the output end of the remote thermometer is electrically connected to the input end of the PLC control system, and the output end of the PLC control system is electrically connected to the control end of the pressure regulating pump.

[0018] In some embodiments of the present invention, an online conductivity meter for monitoring the conductivity of the heat exchange medium is also included.

[0019] In some embodiments of the present invention, the online conductivity meter is connected to the voltage-stabilizing tank.

[0020] In some embodiments of the utility model, an alarm device is also included; the output end of the online conductivity meter is electrically connected to the input end of the PLC control system, and the output end of the PLC control system is electrically connected to the input end of the alarm device.

[0021] In some embodiments of the present invention, the heater is an electric heater.

[0022] In some embodiments of the utility model, a desalted water supply pipe connected to the pressure-stabilizing tank is also included; a water supply valve is arranged on the desalted water supply pipe.

[0023] In some embodiments of the utility model, a remote level meter connected to the pressure regulating tank is also included; the output end of the remote level meter is electrically connected to the input end of the PLC control system, and the output end of the PLC control system is electrically connected to the control end of the water supply valve.

[0024] The embodiments of the present invention have at least the following advantages or beneficial effects:

[0025] The waste heat of the air compressor and the cooling capacity of the dirty nitrogen are comprehensively utilized, achieving a two-way complementary energy-saving effect.

[0026] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or may be understood by practicing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a structural schematic diagram of the air compressor waste heat and dirty nitrogen gas cooling recovery energy saving system.

[0029] Icons: 1-dirty nitrogen inlet pipe, 2-heater, 4-air compressor cylinder, 5-circulating heat exchange pipe, 6-heat exchanger, 7-pressure regulating tank, 8-pressure regulating pump, 9-remote thermometer, 10-desalted water supply pipe, 11-remote liquid level gauge, 12-water supply valve, 13-online conductivity meter, 14-PLC control system. DETAILED DESCRIPTION

[0030] In the following, only some exemplary embodiments are briefly described. As those skilled in the art can appreciate, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present invention.

[0031] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0032] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0033] Example

[0034] See also Figure 1 The present embodiment provides an air compressor waste heat and contaminated nitrogen gas cooling capacity recovery and energy saving system, comprising a contaminated nitrogen gas input pipe 1, a heater 2, a purifier, an air compressor cylinder 4, a circulating heat exchange pipe 5 and a heat exchanger 6.

[0035] The dirty nitrogen gas input pipe 1, the heater 2 and the purifier are connected in sequence. The heater 2 is an electric heater 2.

[0036] The heat exchange medium in the circulating heat exchange pipe 5 circulates through the air compressor cylinder 4 and the heat exchanger 6 .

[0037] The contaminated nitrogen in the contaminated nitrogen inlet pipe 1 first passes through the heat exchanger 6 and the circulating heat exchange pipe 5 for heat exchange before entering the heater 2 .

[0038] The dirty nitrogen gas is guided by the dirty nitrogen gas input pipe 1 through the heat exchanger 6, and heat is exchanged with the heat exchange medium in the circulating heat exchange pipe 5 that has absorbed the heat of the air compressor cylinder 4 in the heat exchanger 6. On the one hand, the dirty nitrogen gas can be preheated by the heat exchange medium in the circulating heat exchange pipe 5 before entering the heater 2, so as to reduce the energy consumption of the heater 2; on the other hand, the temperature of the heat exchange medium is reduced after the heat exchange with the dirty nitrogen gas, and the heat exchange medium can cool the air compressor cylinder 4 when passing through the air compressor cylinder 4 again, especially in summer. The heat exchange and cooling effect of the air compressor cylinder 4 can be enhanced, thereby reducing the overall power consumption of the air compressor. This system has a two-way complementary energy-saving effect.

[0039] The air compressor waste heat and dirty nitrogen gas cooling capacity recovery and energy-saving system also includes a pressure-stabilizing tank 7 and a pressure-stabilizing pump 8 arranged on the path of the circulating heat exchange tube 5. The heat exchange medium in the circulating heat exchange tube 5 first flows through the pressure-stabilizing tank 7 and the pressure-stabilizing pump 8, and then passes through the heat exchanger 6. The arrangement of the pressure-stabilizing tank 7 and the pressure-stabilizing pump 8 can stabilize the flow and pressure of the heat exchange medium passing through the heat exchanger 6, thereby ensuring the heat exchange effect.

[0040] In order to ensure the stable operation of the system, the pressure-stabilizing pump 8 is a variable frequency pump, and a remote thermometer 9 is provided on the pressure-stabilizing tank 7. The output end of the remote thermometer 9 is electrically connected to the input end of the PLC control system 14, and the output end of the PLC control system 14 is electrically connected to the control end of the pressure-stabilizing pump 8. The PLC control system 14 and the remote thermometer 9 are interlocked to control the output load of the pressure-stabilizing pump 8, that is, when the water temperature of the pressure-stabilizing tank 7 is lower than the set value a, the frequency of the pressure-stabilizing pump 8 is reduced, the circulation flow rate becomes lower and the heat exchange efficiency is reduced; when the water temperature of the pressure-stabilizing tank 7 is higher than the set value b, the frequency of the pressure-stabilizing pump 8 is increased (a<b), the circulation flow rate becomes larger and the heat exchange efficiency is increased.

[0041] The air compressor waste heat and dirty nitrogen gas cooling energy recovery and energy-saving system also includes a desalted water supply pipe 10 and a remote level gauge 11 connected to the pressure-stabilizing tank 7; a water supply valve 12 is arranged on the desalted water supply pipe 10; the output end of the remote level gauge 11 is electrically connected to the input end of the PLC control system 14, and the output end of the PLC control system 14 is electrically connected to the control end of the water supply valve 12. The PLC control system 14 and the remote level gauge 11 interlock to control the opening and closing of the water supply valve 12, that is, when the liquid level of the pressure-stabilizing tank 7 is reduced to the lower limit value, the water supply valve 12 is automatically opened, and when the liquid level of the pressure-stabilizing tank 7 is replenished to a suitable level, the water supply valve 12 is automatically closed.

[0042] The air compressor waste heat and contaminated nitrogen gas cooling capacity recovery energy-saving system also includes an online conductivity meter 13 connected to the pressure-stabilizing tank 7 , and the online conductivity meter 13 is used to monitor the conductivity of the heat exchange medium in the pressure-stabilizing tank 7 .

[0043] The air compressor waste heat and dirty nitrogen gas cooling capacity recovery and energy saving system also includes an alarm device (not shown in the figure); the output end of the online conductivity meter 13 and the output end of the remote thermometer 9 are electrically connected to the input end of the PLC control system 14, and the output end of the PLC control system 14 is electrically connected to the input end of the alarm device; the output end of the online conductivity meter 13, the remote thermometer 9, the PLC control system 14 and the alarm device constitute a DCS alarm subsystem, and the DCS alarm subsystem is configured as follows:

[0044] 1. When the online conductivity meter 13>500us / cm, the alarm is triggered, and the alarm device warns by sound, light, etc.;

[0045] 2. When the temperature of the pressure regulating tank 7 is greater than the set value a, the alarm is triggered, and the alarm device warns by sound, light, etc.;

[0046] 3. When the temperature of the pressure regulating tank 7 is less than the set value b, the alarm is triggered and the alarm device gives warnings by sound, light, etc.

[0047] In combination with the above content, this embodiment has at least the following beneficial effects:

[0048] 1. This embodiment comprehensively utilizes the waste heat of the air compressor and the coldness of the dirty nitrogen gas, achieving a two-way complementary energy-saving effect.

[0049] 2. Taking the Hanwha nitrogen air compressor with an intake of 17500Nm³ / h as an example, the power is 2100KW, and taking the Hanwha instrument air compressor with an intake of 8500Nm3 / h as an example, the power is 1050KW; the power of electric heater 2 is 480KW. The comprehensive energy saving of this system is about 5%, and it is estimated that 360KW / h of electricity can be saved per hour. The cumulative operation of 8000 hours throughout the year can save 1.44 million kWh of electricity, with significant economic benefits.

[0050] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. In the absence of conflicts, the embodiments of the present application and the features in the embodiments may be combined with each other at will. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An air compressor waste heat and dirty nitrogen cooling recovery energy saving system, characterized in that: include: Dirty nitrogen gas inlet pipe; Heater; Purifier; Air compressor cylinder; Circulating heat exchange tubes; and Heat exchanger; The contaminated nitrogen gas input pipe, the heater and the purifier are connected in sequence. Before entering the heater, the contaminated nitrogen gas in the contaminated nitrogen gas input pipe first passes through the heat exchanger to exchange heat with the circulating heat exchange pipe. The heat exchange medium in the circulating heat exchange pipe circulates through the air compressor cylinder and the heat exchanger.

2. The air compressor waste heat and contaminated nitrogen cooling energy recovery energy saving system according to claim 1 is characterized in that: It also includes a pressure stabilizing tank and a pressure stabilizing pump arranged on the path of the circulating heat exchange tube; the heat exchange medium in the circulating heat exchange tube first flows through the pressure stabilizing tank and the pressure stabilizing pump, and then passes through the heat exchanger.

3. The air compressor waste heat and contaminated nitrogen gas cooling energy recovery energy saving system according to claim 2 is characterized in that: The pressure-stabilizing pump is a variable-frequency pump.

4. The air compressor waste heat and contaminated nitrogen cooling energy recovery energy saving system according to claim 3 is characterized in that: The pressure stabilizing tank is provided with a remote thermometer, the output end of the remote thermometer is electrically connected to the input end of the PLC control system, and the output end of the PLC control system is electrically connected to the control end of the pressure stabilizing pump.

5. The air compressor waste heat and contaminated nitrogen gas cooling energy recovery and energy saving system according to claim 4 is characterized in that: Also included is an online conductivity meter for monitoring the conductivity of the heat exchange medium.

6. The air compressor waste heat and contaminated nitrogen gas cooling energy recovery energy saving system according to claim 5 is characterized in that: The online conductivity meter is connected to the voltage stabilizing tank.

7. The air compressor waste heat and contaminated nitrogen gas cooling energy recovery and energy saving system according to claim 5 is characterized in that: It also includes an alarm device; the output end of the online conductivity meter is electrically connected to the input end of the PLC control system, and the output end of the PLC control system is electrically connected to the input end of the alarm device.

8. The air compressor waste heat and contaminated nitrogen gas cooling energy recovery and energy saving system according to claim 1 is characterized in that: The heater is an electric heater.

9. The air compressor waste heat and contaminated nitrogen cooling energy recovery energy saving system according to any one of claims 2 to 7, characterized in that: It also includes a desalted water replenishment pipe connected to the pressure stabilizing tank; the desalted water replenishment pipe is provided with a replenishment valve.

10. The air compressor waste heat and contaminated nitrogen gas cooling energy recovery and energy saving system according to claim 9 is characterized in that: It also includes a remote level meter connected to the pressure-stabilizing tank; the output end of the remote level meter is electrically connected to the input end of the PLC control system, and the output end of the PLC control system is electrically connected to the control end of the water supply valve.

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