Recovery device for residual liquid ammonia and gaseous ammonia in liquid ammonia filling tank car

Abstract

The utility model provides a device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia filling tank car, which comprises a liquid ammonia storage tank, a compressor, a two-position four-way valve, a liquid phase pipe and a gaseous phase pipe, the gaseous phase pipe is connected with the top of the liquid ammonia filling tank car and the top of the liquid ammonia storage tank, the liquid phase pipe is connected with the bottom of the liquid ammonia filling tank car and the bottom of the liquid ammonia storage tank, and the compressor is connected with the two-position four-way valve. The gas phase pipe is connected with a bypass pipeline, the bypass pipeline is connected to two opposite ports of the two-position four-way valve, and the two ends of the compressor are connected to the remaining two ports of the two-position four-way valve. Liquid ammonia and gas ammonia left in the liquid ammonia filling tank car are effectively recycled through pressurization, zero emission of liquid ammonia filling is achieved, the problem that the liquid ammonia and the gas ammonia left in the liquid ammonia filling tank car are difficult to recycle during liquid ammonia filling operation is solved, waste caused by liquid ammonia filling operation and material loss is eliminated, and the environment of a liquid ammonia filling site is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of synthetic ammonia production, in particular to a device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia filling tank truck. Background Art

[0002] Ammonia is an inorganic compound with the chemical formula NH, a molecular weight of 17.031, colorless, and a strong pungent odor. It is easily liquefied into a colorless liquid. It can be liquefied by applying pressure at room temperature (critical temperature 132.4°C, critical pressure 11.2 MPa, i.e. 112.2 atmospheres).

[0003] Liquid ammonia is mainly transported to various customer locations by filling tank trucks. After the tank trucks are unloaded, they return to the filling station to be filled with liquid ammonia. After the liquid ammonia in the tank truck is unloaded into the storage tank, since the liquid outlet of the tank truck tank is at a certain height from the bottom of the tank, the tank truck cannot be parked in a horizontal state. A considerable amount of liquid ammonia and non-condensable ammonia gas will remain in the tank truck tank and cannot be completely unloaded. If the residual liquid ammonia and gas ammonia in the tank truck are not recovered, it will cause economic losses to the user and also bring difficulties to the next filling operation. Therefore, the liquid ammonia and gas ammonia in the tank truck must be recovered. If this part of the exhaust gas is sent to the flare for combustion, the ammonia cannot be recovered, resulting in a large loss and environmental pollution; if the low-pressure exhaust gas is sent to the inlet of the ice machine to recover ammonia, the non-condensable gas in the ammonia condenser of the ice machine will accumulate more, the outlet pressure of the ice machine will increase, and the load of the ice machine will increase; if the low-pressure exhaust gas is sent to the isobaric ammonia recovery tower to absorb ammonia, the pressure of the isobaric ammonia recovery tower can only be reduced to absorb ammonia under reduced pressure, and the ammonia recovery effect of the relaxation gas is poor; the ammonia in the low-pressure exhaust gas is recovered separately by the ammonia recovery tower to prepare concentrated ammonia water (220~280t) for sale, which is less economical. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia filling tank truck. In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0005] A device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia filling tank truck, comprising a liquid ammonia storage tank, a compressor, a two-position four-way valve, a liquid phase pipe and a gas phase pipe, wherein the gas phase pipe is connected to the top of the liquid ammonia filling tank truck and the liquid ammonia storage tank, the liquid phase pipe is connected to the bottom of the liquid ammonia filling tank truck and the liquid ammonia storage tank, the gas phase pipe is connected to a bypass pipeline, the bypass pipeline is connected to two opposite ports of the two-position four-way valve, and both ends of the compressor are connected to the remaining two ports of the two-position four-way valve.

[0006] Furthermore, a tank truck filling valve and a tank truck gas phase valve are respectively provided at both ends of the liquid ammonia filling tank truck, the tank truck filling valve is installed on the liquid phase pipe, and the tank truck gas phase valve is installed on the gas phase pipe. A tank feed valve and a tank gas phase valve are provided at both ends of the liquid ammonia storage tank, the tank feed valve is arranged on the liquid phase pipe, and the tank gas phase valve is arranged on the gas phase pipe.

[0007] Furthermore, a four-way front cut-off valve and a four-way rear cut-off valve are provided on the bypass pipeline, and the four-way front cut-off valve and the four-way rear cut-off valve are respectively located on both sides of the two-position four-way valve. A gas phase bypass valve is provided on the gas phase pipe, and the gas phase bypass valve is located between the bypass pipeline and the gas phase pipe connecting end.

[0008] Furthermore, the compressor is an oil-free piston compressor, and the two-position four-way valve is a two-position four-way plunger valve.

[0009] Compared with the prior art, the utility model has the following beneficial effects:

[0010] By pressurizing, the residual liquid ammonia and gaseous ammonia in the liquid ammonia filling tank truck can be effectively recovered, achieving zero emission from liquid ammonia filling, solving the problem of difficulty in recovering residual liquid ammonia and gaseous ammonia in the liquid ammonia tank truck during liquid ammonia filling operations, eliminating the waste of liquid ammonia filling operations and material loss, and greatly improving the environment of the liquid ammonia filling site. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0012] Figure 1 This is a schematic diagram of the structure of the four-way valve in the embodiment of the utility model in the normal position;

[0013] Figure 2 This is a schematic diagram of the structure of the four-way valve in the reverse position according to an embodiment of the utility model.

[0014] In the above drawings: liquid ammonia filling tank truck 1, compressor 2, liquid ammonia storage tank 3, two-position four-way valve 4, tank truck filling valve 5, storage tank feed valve 6, tank truck gas phase valve 7, four-way front cut-off valve 8, four-way rear cut-off valve 9, storage tank gas phase valve 10, gas phase bypass valve 11, liquid phase pipe 12, gas phase pipe 13, bypass pipeline 14. DETAILED DESCRIPTION

[0015] The technical solution of the present utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0016] Please refer to Figure 1 , Figure 2As shown, a device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia filling tank truck comprises a liquid ammonia storage tank 3, a compressor 2, a two-position four-way valve 4, a liquid phase pipe 12 and a gas phase pipe 13, wherein the gas phase pipe 13 is connected to the top of the liquid ammonia filling tank truck 1 and the liquid ammonia storage tank 3, the liquid phase pipe 12 is connected to the bottom of the liquid ammonia filling tank truck 1 and the liquid ammonia storage tank 3, a bypass pipeline 14 is connected to the gas phase pipe 13, the bypass pipeline 14 is connected to two opposite ports of the two-position four-way valve 4, and both ends of the compressor 2 are connected to the remaining two ports of the two-position four-way valve 4.

[0017] In this embodiment, please refer to Figure 1 , Figure 2 As shown, a tank truck filling valve 5 and a tank truck gas phase valve 7 are respectively provided at both ends of the liquid ammonia filling tank truck 1. The tank truck filling valve 5 is installed on the liquid phase pipe 12, and the tank truck gas phase valve 7 is installed on the gas phase pipe 13, which are used to control the flow of ammonia flowing to the liquid ammonia filling tank truck 1. A tank feed valve 6 and a tank gas phase valve 10 are provided at both ends of the liquid ammonia storage tank 3. The tank feed valve 6 is arranged on the liquid phase pipe 12, and the tank gas phase valve 10 is arranged on the gas phase pipe 13, which are used to control the flow of ammonia flowing to the liquid ammonia storage tank 3.

[0018] In this embodiment, please refer to Figure 1 , Figure 2 As shown, the bypass pipeline 14 is provided with a four-way front cut-off valve 8 and a four-way rear cut-off valve 9, which are respectively located on both sides of the two-position four-way valve 4, and the gas phase pipe 13 is provided with a gas phase bypass valve 11, which is located between the bypass pipeline 14 and the connecting end of the gas phase pipe 13. Closing the four-way front cut-off valve 8 and the four-way rear cut-off valve 9 facilitates the inspection and replacement of the two-position four-way valve 4.

[0019] When unloading liquid ammonia, the tanker filling valve 5 and the tank feed valve 6 on the liquid phase pipe 12 between the liquid ammonia filling tanker 1 and the liquid ammonia storage tank 3 are opened to allow the liquid in the liquid ammonia filling tanker 1 to automatically flow into the liquid ammonia storage tank 3. When the pressure of the liquid ammonia filling tanker 1 and the liquid ammonia storage tank 3 reaches equilibrium, the flow is stopped. At this time, the gas phase bypass valve 11 is closed, the compressor 2 is started, and the two-position four-way valve 2 is adjusted to be in the normal position. Figure 1 As shown, the arrow indicates the flow direction of ammonia. The gas is extracted from the liquid ammonia storage tank 3 by the compressor 2 and then pressurized and discharged into the liquid ammonia filling tank truck 1. At this time, the pressure in the liquid ammonia filling tank truck 1 increases, and the pressure in the liquid ammonia storage tank 3 decreases. The liquid in the liquid ammonia filling tank truck 1 continues to flow into the liquid ammonia storage tank 3, so as to achieve the purpose of recovering the residual liquid ammonia in the liquid ammonia filling tank truck 1.

[0020] After the residual liquid ammonia in the liquid ammonia filling tank truck 1 is recovered, the tank truck filling valve 5 and the liquid ammonia storage tank feed valve 6 on the liquid phase pipe 12 between the liquid ammonia filling tank truck 1 and the liquid ammonia storage tank 3 are closed, and the tank truck gas phase valve 7, the four-way front cut-off valve 8 and the four-way rear cut-off valve 9 on the gas phase pipe 13 between the liquid ammonia filling tank truck 1 and the liquid ammonia storage tank 3 are opened, the compressor 2 is started, and the two-position four-way valve 4 is adjusted to the reverse position, such as Figure 2 As shown, the arrow indicates the flow direction of ammonia. At this time, the remaining gas in the liquid ammonia filling tank truck 1 is sucked in by the compressor 2, and is discharged to the liquid ammonia storage tank 3 after being pressurized, until the pressure of the remaining gas drops to a point where there is no recovery value, thereby achieving the purpose of recovering the residual gas ammonia in the liquid ammonia filling tank truck 1.

[0021] The two-position four-way valve 4 uses a two-position four-way plunger valve. The compressor 2 is preferably an oil-free piston compressor 2 with low price and convenient operation. When the compressor 2 is running, the rotary motion is converted into the reciprocating motion of the piston in the cylinder through the crankshaft, connecting rod and crosshead, and the working volume is periodically changed to complete the four working processes of suction, compression, exhaust and expansion. When the piston moves from the outer stop point to the inner stop point, the intake valve opens, the gas enters the cylinder, and the suction begins; when it reaches the inner stop point, the suction ends; when the piston moves from the inner stop point to the outer stop point, the gas is compressed. When the pressure in the cylinder exceeds the back pressure in its exhaust pipe, the exhaust valve opens, that is, the exhaust begins, and when the piston reaches the outer stop point, the exhaust ends. The piston moves from the outer stop point to the inner stop point again, and the high-pressure gas in the cylinder clearance expands. When the pressure in the suction pipe is greater than the pressure of the gas expanding in the cylinder and can overcome the spring force of the intake valve, the intake valve opens. At this moment, the expansion ends, and the compressor 2 completes a working cycle.

[0022] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia tanker, characterized in that: It includes a liquid ammonia storage tank, a compressor, a two-position four-way valve, a liquid phase pipe and a gas phase pipe. The gas phase pipe is connected to the top of the liquid ammonia filling tank truck and the liquid ammonia storage tank, and the liquid phase pipe is connected to the bottom of the liquid ammonia filling tank truck and the liquid ammonia storage tank. The gas phase pipe is connected to a bypass pipeline, and the bypass pipeline is connected to two opposite ports of the two-position four-way valve. The two ends of the compressor are connected to the remaining two ports of the two-position four-way valve.

2. The device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia tanker according to claim 1, characterized in that: The two ends of the liquid ammonia filling tank truck are respectively provided with a tank truck filling valve and a tank truck gas phase valve, the tank truck filling valve is installed on the liquid phase pipe, and the tank truck gas phase valve is installed on the gas phase pipe. The two ends of the liquid ammonia storage tank are provided with a tank feed valve and a tank gas phase valve, the tank feed valve is arranged on the liquid phase pipe, and the tank gas phase valve is arranged on the gas phase pipe.

3. The device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia tanker according to claim 1, characterized in that: A four-way front cut-off valve and a four-way rear cut-off valve are arranged on the bypass pipeline, and the four-way front cut-off valve and the four-way rear cut-off valve are respectively located on both sides of the two-position four-way valve. A gas phase bypass valve is arranged on the gas phase pipe, and the gas phase bypass valve is located between the bypass pipeline and the gas phase pipe connection end.

4. The device for recovering residual liquid ammonia and gaseous ammonia in a liquid ammonia tanker according to claim 1, characterized in that: The compressor is an oil-free piston compressor, and the two-position four-way valve is a two-position four-way plunger valve.

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