Liquid ammonia unloading and conveying system utilizing pressure difference

Abstract

The utility model relates to a liquid ammonia unloading and conveying system utilizing pressure difference. The liquid ammonia unloading and conveying system comprises a circulating water ammonia evaporator, a liquid ammonia storage tank, a liquid ammonia evaporator and a tank car, the circulating water ammonia evaporator is communicated with the liquid ammonia storage tank through a first communicating pipe, the liquid ammonia storage tank is communicated with the liquid ammonia evaporator through a second communicating pipe, the first communicating pipe is communicated with the tank car through a third communicating pipe, and the tank car is communicated with the liquid ammonia storage tank through a fourth communicating pipe. According to the system, the dependence of a liquid ammonia pump is eliminated, a mechanical pump is replaced by differential pressure, and the leakage risk (dynamic sealing points are reduced) and the operation cost (power consumption and maintenance of the pump are not needed) are reduced. In addition, liquid ammonia is evaporated through 65 DEG C hot water, waste heat of a factory is reasonably utilized, and extra energy consumption is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to nitric acid production field especially utilizes the liquid ammonia unloading and conveying system of pressure difference. BACKGROUND

[0002] At present, most domestic dilute nitric acid production enterprises adopt double pressurization production process, that is, ammonia gas reacts with oxygen in air to generate nitrogen oxides under low pressure, and nitrogen oxides are pressurized to form dilute nitric acid by water absorption. The raw material liquid ammonia of most enterprises is unloaded into a liquid ammonia storage tank mainly through a liquid ammonia pump, then the liquid ammonia is transported to a dilute nitric acid device liquid ammonia evaporator for evaporation and gasification by the liquid ammonia pump, and then ammonia gas after ammonia gas separation and ammonia gas superheating process is mixed with oxygen in air to react. The liquid ammonia unloading and conveying are all pressurized by the liquid ammonia pump, which increases the risk of leakage and operating cost. UTILITARIAN CONTENT

[0003] Therefore, the utility model aims at providing a liquid ammonia unloading and conveying system utilizing pressure difference to solve the problems in the prior art.

[0004] To achieve the above-mentioned purpose, the technical scheme of the utility model is as follows:

[0005] The utility model provides a liquid ammonia unloading and conveying system utilizing pressure difference, which comprises a circulating water ammonia evaporator, a liquid ammonia storage tank, a liquid ammonia evaporator and a tank car.

[0006] The circulating water ammonia evaporator is communicated with the liquid ammonia storage tank through a first communication pipe, the liquid ammonia storage tank is communicated with the liquid ammonia evaporator through a second communication pipe, the first communication pipe is communicated with the tank car through a third communication pipe, and the tank car is communicated with the liquid ammonia storage tank through a fourth communication pipe.

[0007] A circulating water assembly is arranged on the circulating water ammonia evaporator.

[0008] Further, the circulating water assembly comprises a water inlet pipe and a water outlet pipe which are communicated with the circulating water ammonia evaporator respectively.

[0009] Further, pneumatic valves are arranged on the pipelines of the first communication pipe, the second communication pipe, the third communication pipe and the fourth communication pipe.

[0010] Further, a liquid level sensor is arranged in the liquid ammonia storage tank.

[0011] Further, pressure sensors are arranged in the circulating water ammonia evaporator, the liquid ammonia storage tank, the liquid ammonia evaporator and the tank car.

[0012] Compared with the prior art, the utility model has the following advantages:

[0013] In the utility model, the system eliminates the dependence of liquid ammonia pump, substitutes mechanical pump by pressure difference, reduces the risk of leakage (reduces dynamic sealing point) and operation cost (no power consumption and maintenance of pump are needed). In addition, liquid ammonia is evaporated by 65 DEG C hot water, the waste heat of factory is reasonably utilized, and additional energy consumption is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0014] The drawings constituting a part of the utility model are used to provide further understanding of the utility model, the illustrative embodiment of the utility model and the explanation thereof are used to explain the utility model, and do not constitute improper limitation on the utility model. In the drawings:

[0015] Figure 1 It is the whole structure schematic diagram of the utility model.

[0016] Explanation of reference signs:

[0017] 1, circulating water ammonia evaporator;101, water inlet pipe;102, water outlet pipe;103, first communication pipe;2, liquid ammonia storage tank;201, second communication pipe;3, liquid ammonia evaporator;4, third communication pipe;401, fourth communication pipe;5, pneumatic valve;6, liquid level sensor;7, pressure sensor;8, tank car. DETAILED DESCRIPTION

[0018] It should be noted that the embodiments in the utility model and the features in the embodiments can be combined with each other without conflict.

[0019] In the description of the utility model, it should be noted that the terms "upper", "lower", "inner", "back" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0020] In addition, in the description of the utility model, unless otherwise explicitly limited, the terms "mounting", "connection", "connection", "connection" should be broadly understood. For example, it can be fixedly connected, or it can be detachably connected, or integrally connected;It can be mechanically connected, or it can be electrically connected;It can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood in combination with the specific circumstances.

[0021] The utility model will be described in detail below with reference to the accompanying Figure 1 and combined with the embodiments.

[0022] The utility model relates to a kind of liquid ammonia unloading and conveying system using pressure difference, including circulating water ammonia evaporator 1, liquid ammonia storage tank 2, liquid ammonia evaporator 3, and tank truck 8;Circulating water ammonia evaporator 1 is communicated with liquid ammonia storage tank 2 by first communication pipe 103, liquid ammonia storage tank 2 is communicated with liquid ammonia evaporator 3 by second communication pipe 201, first communication pipe 103 is communicated with tank truck 8 by third communication pipe 4, tank truck 8 is communicated with liquid ammonia storage tank 2 by fourth communication pipe 401;Circulating water assembly is equipped on circulating water ammonia evaporator 1.

[0023] Specific operation, 65 ℃ hot water is passed into circulating water ammonia evaporator 1, and liquid ammonia is evaporated as gas ammonia.Gas ammonia is divided into two ways: first way: via first communication pipe 103 is sent to liquid ammonia storage tank 2, and the storage tank pressure is lifted to 1.1MPa (higher than liquid ammonia evaporator 2), drives liquid ammonia to flow to liquid ammonia evaporator 3.Second way: via first communication pipe 103 is sent to third communication pipe 4, and liquid ammonia tank truck 8 is pressurized to 0.8MPa (higher than liquid ammonia storage tank 2), to make liquid ammonia in liquid ammonia tank truck 8 flow into liquid ammonia storage tank 2.

[0024] Further, unloading stage: after liquid ammonia storage tank 2 is pressurized, liquid ammonia flows into liquid ammonia storage tank 2 from tank truck 8 under 0.8MPa→1MPa pressure difference.

[0025] Transport stage: liquid ammonia in liquid ammonia storage tank 2 flows into liquid ammonia evaporator 3 under 1.1MPa→low pressure of liquid ammonia evaporator 3 pressure difference, and is evaporated as gas ammonia to produce.

[0026] Overall, the system eliminates liquid ammonia pump dependence, replaces mechanical pump by pressure difference, reduces leakage risk (reduces dynamic sealing point) and operating cost (no need for power consumption and maintenance of pump).In addition, liquid ammonia is evaporated by 65 ℃ hot water, and factory waste heat is reasonably utilized, and additional energy consumption is reduced.

[0027] Based on the above setting, circulating water assembly is used to provide circulation for hot water in circulating water ammonia evaporator 1, and circulating water assembly includes water inlet pipe 101 and water outlet pipe 102 communicated with circulating water ammonia evaporator 1 respectively.

[0028] Specific implementation, 65 ℃ hot water enters circulating water ammonia evaporator 1 from water inlet pipe 101 by circulating water pump, and flows through heat exchange pipe or coil in evaporator.Hot water exchanges heat with liquid ammonia in evaporator, and liquid ammonia absorbs heat and evaporates as gas ammonia, and hot water temperature drops to about 50-55 ℃.After cooling, hot water returns to circulating water system through water outlet pipe 102, and is reheated to 65 ℃ by waste heat recovery device (such as nitrogen oxide heat exchanger recovers process gas waste heat), to complete closed cycle.

[0029] It needs to be further explained that the pipeline of the first communication pipe 103, the second communication pipe 201, the third communication pipe 4 and the fourth communication pipe 401 is provided with a pneumatic valve 5. Through the accurate control of the pneumatic valve 5 and the multi-stage safety interlocking, the liquid ammonia unloading and conveying system realizes safe, efficient and intelligent operation.

[0030] In addition, the liquid ammonia storage tank 2 is provided with a liquid level sensor 6. The liquid level sensor 6 (such as a magnetic float liquid level meter, a radar liquid level meter or an externally attached ultrasonic liquid level meter) monitors the liquid level in the storage tank in real time through the buoyancy principle, ultrasonic pulse or magnetic coupling technology, can real-time feedback the liquid ammonia height in the liquid ammonia storage tank 2, and avoid accidents.

[0031] In addition, the circulating water ammonia evaporator 1, the liquid ammonia storage tank 2, the liquid ammonia evaporator 3 and the tank truck 8 are provided with a pressure sensor 7. The pressure sensor 7 monitors the pressure of the storage tank and the pipeline in real time, and sends an alarm when the pressure exceeds the safety threshold, avoiding the storage tank rupture or leakage accident.

[0032] In the embodiment, the type of the liquid level sensor is preferably an optical liquid level sensor 6FS-IR2003D. The type of the pressure sensor 7 is preferably a sputtering thin film pressure sensor 7HK1100C.

[0033] The above only describes the preferred embodiment of the utility model, and does not limit the utility model, and any modification, equivalent replacement, improvement, etc. within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A liquid ammonia unloading and conveying system using pressure difference, characterized in that: it comprises a circulating water ammonia evaporator (1), a liquid ammonia storage tank (2), a liquid ammonia evaporator (3), and a tank truck (8); the circulating water ammonia evaporator (1) is communicated with the liquid ammonia storage tank (2) through a first communication pipe (103), the liquid ammonia storage tank (2) is communicated with the liquid ammonia evaporator (3) through a second communication pipe (201), the first communication pipe (103) is communicated with the tank truck (8) through a third communication pipe (4), and the tank truck (8) is communicated with the liquid ammonia storage tank (2) through a fourth communication pipe (401); a circulating water assembly is arranged on the circulating water ammonia evaporator (1).

2. The liquid ammonia unloading and conveying system using pressure difference according to claim 1, characterized in that: the circulating water assembly comprises a water inlet pipe (101) and a water outlet pipe (102) respectively communicated with the circulating water ammonia evaporator (1).

3. The liquid ammonia unloading and conveying system using pressure difference according to claim 1, characterized in that: pneumatic valves (5) are arranged on the pipelines of the first communication pipe (103), the second communication pipe (201), the third communication pipe (4), and the fourth communication pipe (401).

4. The liquid ammonia unloading and conveying system using pressure difference according to claim 1, characterized in that: a liquid level sensor (6) is arranged in the liquid ammonia storage tank (2).

5. The liquid ammonia unloading and conveying system using pressure difference according to claim 1, characterized in that: pressure sensors (7) are arranged in the circulating water ammonia evaporator (1), the liquid ammonia storage tank (2), the liquid ammonia evaporator (3), and the tank truck (8).

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