CN205073691U - Liquid ammonia vaporization system - Google Patents

Abstract

The utility model discloses a liquid ammonia evaporation system, which belongs to the field of chemical production. The connection between the ammonia flash tank and the liquid ammonia main evaporator and/or the liquid ammonia air cooler is used to control the output and pressure of gas ammonia, the amount of circulating water and the degree of cooling of circulating water, the flow rate of cooling air and cooling temperature, etc., to meet the requirements of According to the different needs of the factory, the impurities in the device are treated uniformly to achieve the convenience of pressure control in the ammonia evaporation process, energy saving, implementation of cleaning and diversion, regular discharge of impurities, high evaporation efficiency, and the use of rich and low-grade heat sources. Produces cooling air, and the ammonia gas produced by evaporation has the purpose of being clean and high.

Description

A liquid ammonia evaporation system

technical field

The utility model belongs to the field of chemical production and relates to a system for evaporating liquid ammonia into gaseous ammonia, in particular to a liquid ammonia evaporation system capable of evaporating liquid ammonia into saturated gaseous ammonia and delivering it to subsequent users at a certain pressure. system.

Background technique

Synthetic ammonia is the foundation of the modern chemical industry. Through the processing of synthetic ammonia, inorganic industries such as nitric acid and chemical fertilizers were produced. During the use of synthetic ammonia, it is generally necessary to evaporate liquid ammonia into a gaseous state for chemical reactions. The evaporation of liquid ammonia is generally carried out through the evaporator under the required pressure, and the evaporation is carried out by exchanging heat with the liquid ammonia at a saturation temperature higher than the pressure of the heat medium. During the evaporation process, the pressure of the outlet gas ammonia should be kept stable, and a small amount of impurities in the liquid ammonia should not be brought into the subsequent system, and energy should be saved as much as possible. In order to achieve the above purpose, the ammonia evaporation system has a variety of settings, but some ammonia evaporation systems use fresh steam to heat and waste energy, some ammonia evaporation systems are difficult to control the pressure and are not conducive to subsequent ammonia processing, and some ammonia evaporation systems have no impurities, The oil pollution separation device is not safe.

Contents of the invention

In order to overcome the problems existing in the prior art, the utility model discloses a liquid ammonia evaporation system, which utilizes the combination of circulating water, hot air and a small amount of steam.

The utility model is achieved through the following technical solutions:

A liquid ammonia evaporation system, comprising a liquid ammonia flash tank, a liquid ammonia main evaporator and/or a liquid ammonia air cooler, a blowdown evaporator, and a blowdown buffer tank, wherein:

A liquid ammonia flash tank, the liquid ammonia flash tank is provided with a packing layer for heat exchange, the liquid ammonia flash tank is divided into upper and lower chambers, and the liquid ammonia flash tank upper chamber is provided with a liquid ammonia inlet, The gas ammonia outlet is provided with the first gas ammonia inlet, the second gas ammonia inlet and the third gas ammonia inlet on the side wall of the lower cavity of the liquid ammonia flash tank, and the first liquid ammonia is set at the bottom of the liquid ammonia flash tank lower cavity The outlet, the second liquid ammonia outlet and the sewage outlet are used to make the liquid ammonia entering the liquid ammonia flash tank flash under reduced pressure, pass through the packing layer and contact the gas ammonia in countercurrent heat exchange to generate part of the gas ammonia flash from the liquid ammonia The gas ammonia outlet of the upper chamber of the tank is transported to the subsequent section through the gas ammonia main pipe;

The liquid ammonia main evaporator, the liquid ammonia inlet of the liquid ammonia main evaporator is connected with the first liquid ammonia outlet at the bottom of the lower cavity of the liquid ammonia flash tank through a pipeline, and the liquid ammonia inlet of the liquid ammonia main evaporator is lower than the liquid ammonia inlet. The liquid ammonia outlet at the bottom of the lower chamber of the ammonia flash tank is provided with a gas ammonia outlet on the liquid ammonia main evaporator to communicate with the first gas ammonia inlet in the liquid ammonia flash tank, which is used to transfer the liquid ammonia in the liquid ammonia flash tank Ammonia is distributed to the main evaporator of liquid ammonia by gravity, and a circulating water heat exchange pipeline is installed on the main evaporator of liquid ammonia. The purpose of evaporating liquid ammonia is achieved through heat exchange between circulating water and liquid ammonia, and the gas ammonia produced by evaporation is transported To the liquid ammonia flash tank for heat exchange; there is also a sewage outlet at the bottom of the liquid ammonia main evaporator, which is used to collect and treat impurities in the liquid ammonia main evaporator;

Liquid ammonia air cooler, the liquid ammonia inlet on the liquid ammonia air cooler is connected with the second liquid ammonia outlet at the bottom of the lower chamber of the liquid ammonia flash tank through pipelines, the gas ammonia outlet on the liquid ammonia air cooler is connected to the liquid ammonia flash tank The second liquid ammonia inlet of the steamer is connected, and the bottom of the liquid ammonia air cooler is also equipped with a sewage outlet, which is used to transfer the gas ammonia that is distributed to the liquid ammonia air cooler and air to the liquid ammonia after heat exchange with the air. In the flash tank, the remaining impurities are collected and processed;

Blowdown evaporator, the first feed port, the second feed port, and the third feed port on the blowdown evaporator are respectively connected to the blowdown outlet at the bottom of the liquid ammonia flash tank, the blowdown outlet at the bottom of the liquid ammonia main evaporator, and the liquid ammonia The sewage outlet at the bottom of the air cooler is connected through pipelines, and the first feed port, the second feed port, and the third feed port on the sewage evaporator are all lower than the sewage discharge port at the bottom of the liquid ammonia flash tank, and the liquid ammonia The sewage outlet at the bottom of the main evaporator, the sewage outlet at the bottom of the liquid ammonia air cooler, the gas ammonia outlet on the sewage evaporator is connected with the third gas ammonia inlet on the lower chamber of the liquid ammonia flash tank through the pipeline, and is used to discharge the liquid ammonia. The impurities in the ammonia flash tank, liquid ammonia main evaporator and liquid ammonia air cooler are treated centrally, and most of the liquid ammonia attached to the impurities in the blowdown evaporator is evaporated by steam or steam condensate, and the evaporated gas is Ammonia is recycled to the liquid ammonia flash tank;

The blowdown buffer tank, the feed port on the blowdown buffer tank is connected with the blowdown outlet on the blowdown evaporator, which is used to collect and process non-ammonia impurities, and recover unevaporated liquid ammonia and evaporated gaseous ammonia.

As a preferred embodiment, a gas ammonia filter is added on the gas ammonia main pipe, and a sewage outlet is provided at the bottom of the gas ammonia filter to communicate with the sewage buffer tank for filtering out the ammonia gas in the gas ammonia main pipe. Impurities are collected in the blowdown buffer tank for reprocessing.

As a preferred embodiment, a gas ammonia separator is also provided at the gas ammonia outlet of the liquid ammonia main evaporator, which is used to separate the liquid ammonia entrained in the saturated gas ammonia and return it to the liquid ammonia main evaporator for further evaporation.

As a preferred embodiment, a bypass is provided on the circulating water heat exchange pipeline of the main evaporator of liquid ammonia, and the circulating water entering the main evaporator of liquid ammonia and the bypass adopt split-range adjustment to maintain the pressure of ammonia during the evaporation process.

As a preferred embodiment, a coil is arranged inside the blowdown evaporator, and the coil is located at the middle and lower part of the blowdown evaporator.

The technical scheme of the above-mentioned liquid ammonia evaporation system is: the liquid ammonia from the ammonia storehouse is transported through pipelines first into the liquid ammonia flash tank, and the liquid ammonia flash tank is provided with a packing layer for heat exchange between gas supply ammonia and liquid ammonia, and the liquid ammonia Go down through the packing layer and contact with gas ammonia countercurrently, a part of it is evaporated into gas ammonia, and the gas ammonia is collected at the top of the liquid ammonia flash tank through the packing layer and enters the gas ammonia main pipe; the remaining liquid ammonia is collected at the bottom of the liquid ammonia flash tank, When cooling water is needed, the liquid ammonia flash tank is connected to the bottom of the liquid ammonia main evaporator to form a communication device. Liquid ammonia flows into the liquid ammonia main evaporator from the bottom of the liquid ammonia flash tank by the difference in height, and exchanges heat with circulating water, which can not only evaporate liquid ammonia, but also cool down the circulating water. By controlling the cooling water to enter the liquid ammonia main evaporation The amount of liquid ammonia can be adjusted to adjust the evaporation of liquid ammonia, thereby controlling the pressure of gas ammonia; the gas-liquid separator at the gas ammonia outlet of the liquid ammonia main evaporator separates the liquid ammonia entrained in the saturated gas ammonia and returns it to the liquid ammonia main evaporator At the bottom, the gaseous ammonia after separation returns to the lower part of the filling layer in the liquid ammonia flash tank. When the factory needs cold air, a liquid ammonia air cooler is added, and the liquid ammonia flash tank is connected to the bottom of the liquid ammonia air cooler to form a connecting device. The liquid ammonia enters the liquid ammonia air cooler from the bottom of the liquid ammonia flash tank. The vaporized ammonia is sent to the lower chamber of the liquid ammonia flash tank. After a period of evaporation of liquid ammonia, a certain amount of impurities will accumulate at the bottom of liquid ammonia flash tank, liquid ammonia main evaporator, liquid ammonia air cooler and other equipment. Steam or steam condensate is passed into the evaporator to efficiently evaporate the liquid ammonia attached to the impurities in the blowdown evaporator, recycle the liquid ammonia and gaseous ammonia, and collect the non-ammonia impurities for unified harmless treatment; due to this part Impurities are mainly brought by the synthetic ammonia production system, and its main components include compressor lubricating oil, moisture, catalyst dust, pipeline rust and peeling off, etc. If the above impurities are not discharged from the system in time, the purity of ammonia gas will be affected. Therefore, the part of sewage evaporation is quite critical. In order to ensure the cleanliness of the ammonia gas before it is sent to the next process, an ammonia filter is designed on the ammonia gas main pipe to filter the mist, oil mist and water droplets in it again to ensure the ammonia gas is clean.

The liquid ammonia evaporation system can adjust the connection between the liquid ammonia flash tank and the liquid ammonia main evaporator and/or the liquid ammonia air cooler as required to control the output and pressure of ammonia gas, the amount of circulating water and the cooling degree of circulating water, cooling Air circulation and cooling temperature, etc., to meet the different needs of the factory.

The beneficial effects of the utility model are: the pressure control of the gas ammonia evaporation process is convenient, energy is saved, pollution is cleaned and diverted, impurities are discharged regularly, the evaporation efficiency is high, rich and low-grade heat sources can be used, and cooling air can be generated. Ammonia is clean and high.

Description of drawings

Fig. 1 is the flowchart of the utility model embodiment.

In the figure: 1. Liquid ammonia flash tank, 2. Liquid ammonia main evaporator, 3. Liquid ammonia air cooler, 4. Liquid ammonia blowdown evaporator, 5. Sewage blowdown buffer tank, 6. Gas ammonia filter, 8. Circulating water regulating valve, 9. Circulating water bypass regulating valve, 10. Pressure detection element.

detailed description

In order to better understand the utility model, the utility model is further explained in conjunction with the embodiments.

The liquid ammonia evaporation system shown in Figure 1 includes a liquid ammonia flash tank 1, a liquid ammonia main evaporator 2, a liquid ammonia air cooler 3, a blowdown evaporator 4, and a blowdown buffer tank 5, wherein:

The liquid ammonia flash tank 1 is provided with a filler layer for heat exchange. The liquid ammonia flash tank 1 is divided into upper and lower chambers. Ammonia is transported from the liquid ammonia storehouse to the upper cavity of the liquid ammonia flash tank 1 through pipelines, and a liquid ammonia flow regulating valve 7 is arranged on the delivery pipeline, and a second valve 7 is provided on the side wall of the lower cavity of the liquid ammonia flash tank 1. One gas ammonia inlet, the second gas ammonia inlet and the third gas ammonia inlet, the first liquid ammonia outlet, the second liquid ammonia outlet and the sewage outlet are provided at the bottom of the liquid ammonia flash tank 1 lower cavity, for making the liquid ammonia enter The liquid ammonia in the flash tank 1 is decompressed and flashed, passes through the packing layer and contacts the gas ammonia in countercurrent heat exchange to generate part of the gas ammonia, which is transported from the gas ammonia outlet of the liquid ammonia flash tank upper chamber to the subsequent section through the gas ammonia main pipe;

The liquid ammonia inlet of the liquid ammonia main evaporator 2 is connected with the first liquid ammonia outlet at the bottom of the lower cavity of the liquid ammonia flash tank 1 through a pipeline, and the liquid ammonia inlet of the liquid ammonia main evaporator 2 is lower than the liquid ammonia flash tank 1 The liquid ammonia outlet at the bottom of the lower chamber is provided with a gas ammonia outlet on the liquid ammonia main evaporator 2 to communicate with the first gas ammonia inlet in the liquid ammonia flash tank 1, and a sewage outlet is also provided at the bottom of the liquid ammonia main evaporator. It is used to collect and process impurities in the liquid ammonia main evaporator. A circulating water heat exchange pipeline is provided on the liquid ammonia main evaporator 2 to distribute the liquid ammonia in the liquid ammonia flash tank 1 to the liquid ammonia main evaporator. In device 1, the purpose of evaporating liquid ammonia is achieved through heat exchange between circulating water and liquid ammonia, and the gas ammonia produced by evaporation is transported to the liquid ammonia flash tank for heat exchange. The circulating water heat exchange pipeline also includes a bypass, and is set There is a circulating water regulating valve 8 and a circulating water bypass regulating valve 9, through which the circulating water regulating valve 8 controls the flow of cooling water entering the liquid ammonia main evaporator 2 to adjust the evaporation of liquid ammonia and control the pressure of gaseous ammonia. The pressure of the ammonia is continuously measured through the pressure detection element 10 connected with the gas ammonia main pipe. When the gas ammonia pressure is low, the large circulating water regulating valve 8 will be opened to increase the flow of circulating water into the liquid ammonia main evaporator 2, and simultaneously in order not to If the return of circulating water in the factory is affected, the circulating water bypass regulating valve 9 will be closed at the same time; when the pressure detection element 10 shows that the gas ammonia pressure is high, the circulating water regulating valve 8 will be closed to reduce the flow of circulating water into the liquid ammonia main evaporator 2 At the same time, in order not to affect the circulating water return system of the factory, the large circulating water bypass regulating valve 9 will be opened at the same time to ensure that there will be no flow fluctuations in the circulating water system. There is also a gas ammonia filter 6 on the gas ammonia main pipe. There is a sewage outlet at the bottom of the device 6; a gas ammonia separator is also provided at the gas ammonia outlet of the liquid ammonia main evaporator 2, which is used to separate the liquid ammonia entrained in the saturated gas ammonia and return it to the liquid ammonia main evaporator to continue evaporation ;

Liquid ammonia air cooler 3, the liquid ammonia inlet on the liquid ammonia air cooler 3 is connected with the second liquid ammonia outlet at the bottom of the lower cavity of the liquid ammonia flash tank 1 through pipelines, and the gas ammonia outlet on the liquid ammonia air cooler 3 It is connected with the second liquid ammonia inlet of the liquid ammonia flash tank 1, and the bottom of the liquid ammonia air cooler 3 is also provided with a sewage outlet, which is used to convert the liquid ammonia distributed in the liquid ammonia air cooler 3 into air after heat exchange. The ammonia gas is delivered to the liquid ammonia flash tank 1, and the remaining impurities are collected and processed;

The blowdown evaporator 4, the first feed port, the second feed port, and the third feed port on the blowdown evaporator 4 are respectively connected to the blowdown outlet at the bottom of the liquid ammonia flash tank 1 and the blowdown at the bottom of the liquid ammonia main evaporator 2 port, the blowdown outlet at the bottom of the liquid ammonia air cooler 3 are connected through pipelines, and the first feed port, the second feed port, and the third feed port on the blowdown evaporator 4 are all lower than the liquid ammonia flash tank 1 The sewage outlet at the bottom, the sewage outlet at the bottom of the liquid ammonia main evaporator 2, the sewage outlet at the bottom of the liquid ammonia air cooler 3, the gas ammonia outlet on the sewage evaporator 4 passes through the pipeline and the liquid ammonia flash tank 1 lower cavity The third gas ammonia inlet is connected, which is used for centralized treatment of the impurities in the liquid ammonia flash tank 1, the liquid ammonia main evaporator 2 and the liquid ammonia air cooler 3, and the impurities in the blowdown evaporator 4 are treated by steam or steam condensate Most of the liquefied ammonia attached to it evaporates, and the evaporated gas ammonia is recovered in the liquefied ammonia flash tank 1;

The blowdown buffer tank 5, the feed port on the blowdown buffer tank 5 is connected with the blowdown outlet on the blowdown evaporator 4, and is used for collecting and processing non-ammonia impurities, and recovering unevaporated liquid ammonia and evaporated gaseous ammonia; The sewage buffer tank 5 is also provided with a sewage inlet connected to the sewage outlet at the bottom of the gas ammonia filter 6, and is used to collect the impurities filtered out of the gas ammonia main pipe into the sewage buffer tank for reprocessing.

Claims (5)

1. a liquid ammonia evaporation system, is characterized in that comprising liquefied ammonia flash tank, liquefied ammonia main evaporator and/or liquefied ammonia aerial cooler, discharge evaporator, pollution discharge buffering tank, wherein:

Liquefied ammonia flash tank, the packing layer for heat exchange is provided with in described liquefied ammonia flash tank, for liquefied ammonia flash tank is divided into upper and lower two chambeies, liquefied ammonia flash tank epicoele is provided with liquefied ammonia import, gas ammonia exports, liquefied ammonia flash tank cavity of resorption sidewall is provided with the first gas ammonia import, second gas ammonia import and the 3rd gas ammonia import, the first liquefied ammonia outlet is provided with bottom liquefied ammonia flash tank cavity of resorption, second liquefied ammonia outlet and sewage draining exit, for making to enter liquefied ammonia in liquefied ammonia flash tank through vacuum flashing, to export from the gas ammonia of liquefied ammonia flash tank epicoele through packing layer and gas ammonia counter current contacting heat exchange generating portion gas ammonia and be delivered to follow-up workshop section by gas ammonia house steward,

Liquefied ammonia main evaporator, the first liquefied ammonia bottom the liquefied ammonia import of liquefied ammonia main evaporator and liquefied ammonia flash tank cavity of resorption exports and passes through pipeline connection, and the liquefied ammonia import of described liquefied ammonia main evaporator is lower than the liquefied ammonia outlet bottom liquefied ammonia flash tank cavity of resorption, liquefied ammonia main evaporator is provided with gas ammonia outlet and the first gas ammonia inlet communication in liquefied ammonia flash tank, for the liquefied ammonia in liquefied ammonia flash tank is assigned in liquefied ammonia main evaporator by gravity, liquefied ammonia main evaporator is provided with recirculated water heat exchanging pipe, the object that liquefied ammonia evaporates is reached by recirculated water and liquefied ammonia heat exchange, the gas ammonia that evaporation produces is transported to liquefied ammonia flash tank and carries out heat exchange, also sewage draining exit is provided with, for impurity in liquefied ammonia main evaporator being carried out collection process bottom liquefied ammonia main evaporator,

Liquefied ammonia aerial cooler, the second liquefied ammonia bottom liquefied ammonia import on liquefied ammonia aerial cooler and liquefied ammonia flash tank cavity of resorption exports and passes through pipeline connection, gas ammonia outlet on liquefied ammonia aerial cooler and the second liquefied ammonia inlet communication of liquefied ammonia flash tank, also sewage draining exit is provided with bottom liquefied ammonia aerial cooler, for being transported in liquefied ammonia flash tank by the gas ammonia changed into after the liquefied ammonia be assigned in liquefied ammonia aerial cooler and air heat-exchange, remaining impurity is carried out collection process;

Discharge evaporator, the first charging aperture on discharge evaporator, second charging aperture, 3rd charging aperture respectively with liquefied ammonia flash tank bottom sewage draining exit, sewage draining exit bottom liquefied ammonia main evaporator, sewage draining exit bottom liquefied ammonia aerial cooler passes through pipeline connection, and the first charging aperture on discharge evaporator, second charging aperture, 3rd charging aperture is all lower than the sewage draining exit bottom liquefied ammonia flash tank, sewage draining exit bottom liquefied ammonia main evaporator, sewage draining exit bottom liquefied ammonia aerial cooler, gas ammonia outlet on discharge evaporator is by the 3rd gas ammonia inlet communication on pipeline and liquefied ammonia flash tank cavity of resorption, for by liquefied ammonia flash tank, impurity in liquefied ammonia main evaporator and liquefied ammonia aerial cooler focuses on, by steam or steam condensate, most of liquefied ammonia accompanying on impurity in discharge evaporator is evaporated, the gas ammonia of evaporation is recovered in liquefied ammonia flash tank,

Pollution discharge buffering tank, the charging aperture on pollution discharge buffering tank is communicated with the sewage draining exit on discharge evaporator, for carrying out collection process without ammonia impurity, unevaporated liquefied ammonia and the gas ammonia that evaporated is reclaimed.

2. liquid ammonia evaporation system as claimed in claim 1, it is characterized in that: on described gas ammonia house steward, add gas ammonia filter, and be provided with sewage draining exit in described gas ammonia filter bottom and be communicated with pollution discharge buffering tank, carry out reprocessing for being collected in pollution discharge buffering tank by the impurity filtered out in gas ammonia house steward.

3. liquid ammonia evaporation system as claimed in claim 1, is characterized in that: being also provided with gas ammonia separator in the gas ammonia outlet of liquefied ammonia main evaporator, continuing evaporation for being got off to be back to by the Ammonia separation carried secretly in saturated gas ammonia in liquefied ammonia main evaporator.

4. liquid ammonia evaporation system as claimed in claim 1, is characterized in that: the recirculated water heat exchanging pipe of described liquefied ammonia main evaporator is provided with bypass.

5. liquid ammonia evaporation system as claimed in claim 1, it is characterized in that: be provided with coil pipe in described discharge evaporator, and described coil pipe is positioned at the middle and lower part of discharge evaporator.