Vapor recovery device of methanol daily cabinet

Abstract

A methanol fuel daily cabin is provided with a daily cabin ventilation opening, the top of a methanol storage cabin is provided with a storage cabin ventilation opening, a pressure balance pipeline is arranged between the daily cabin ventilation opening and the storage cabin ventilation opening, the daily cabin ventilation opening is provided with a first stop valve, and the storage cabin ventilation opening is provided with a second stop valve. A compressed air branch pipe extends out of the pressure balance pipeline, a pneumatic stop valve is installed on the compressed air branch pipe, an inlet of the pneumatic stop valve is connected with the compressed air branch pipe, an outlet of the pneumatic stop valve is connected with the ventilation stand column, and a pressure sensor is arranged on the top of the methanol fuel daily cabin and transmits signals to an electromagnetic valve control box. And the electromagnetic valve control box controls the pneumatic stop valve. According to the invention, the methanol storage cabin does not generate pressure reduction or vacuum phenomenon, and inert gas does not need to be supplemented into the cabin; the pressure of the methanol daily cabinet cannot be increased due to increase of methanol liquid and a large amount of volatile methanol gas, and the methanol daily cabinet is ensured to be within a safe pressure range under emergency and special conditions.

Description

Technical Field

[0001] The invention belongs to the field of ship construction and design, and in particular relates to a vapor recovery device of a methanol daily cabinet. Background Art

[0002] According to the specification, all methanol tanks should be filled with inert gas for protection, so that the gas pressure in the methanol tank is maintained within the positive pressure range of about 0.25kpa under any circumstances. In order to protect the structural strength of the methanol tank and prevent the pressure in the tank from increasing or decreasing infinitely in a short period of time, it is required that 1. an independent pressure / vacuum relief valve be installed in each methanol tank and methanol daily cabinet. When the pressure in the tank rises to 0.5kpa, the pressure relief valve automatically opens to release the pressure in the tank to the atmosphere; when the pressure in the tank drops to -0.035kpa, the vacuum relief valve automatically opens to allow air to enter the methanol tank. The pressure in the cabin is increased to the positive pressure range; Requirement 2, a pressure sensor is installed in each methanol cabin, and an alarm is given when the pressure is higher than the set value of 0.35kpa; Requirement 3, when the ship uses methanol as the main engine fuel during navigation, the methanol cabin transfer pump needs to inject methanol liquid into the methanol daily cabinet every 8 hours, which will cause pressure reduction or vacuum phenomenon in the methanol cabin, and pressure increase in the methanol daily cabinet. The steam between the methanol cabin and the methanol daily cabinet is connected through the cabin top connecting pipe between the two, so as to prevent the pressure in the daily cabinet from increasing and the pressure in the methanol cabin from decreasing. The pressure in the two cabins is maintained within a relatively constant range, and the evaporated methanol gas in the daily cabinet is recovered into the methanol cabin, saving a lot of energy.

[0003] Due to the low boiling point and high volatility of methanol liquid, when methanol liquid is injected into the methanol tank, a large amount of volatile gas will be produced, which will increase the pressure inside the tank. Similarly, when methanol liquid is pumped out of the methanol tank, the pressure inside the tank will decrease.

[0004] When methanol is used as fuel to supply oil to the main engine on board, the main engine supply pump draws oil from the methanol daily tank. At this time, the liquid in the tank is reduced and the pressure in the tank is also reduced at any time. In order to maintain the pressure in the tank within a certain range, the inert gas is automatically added to the tank according to the pressure setting value. Usually, the volume of the methanol tank is 8 hours of consumption. The transfer pump in the methanol storage tank automatically controls the transfer pump to transport methanol to the methanol daily tank according to the high and low liquid level signals on the methanol daily tank. Since the injection amount of the transfer pump is much greater than the extraction amount of the main engine supply pump, the injection increases the liquid in the methanol daily tank tank, and at the same time increases a large amount of volatile gas, which increases the pressure of the daily tank in a short time. When the pressure is greater than the pressure / vacuum release valve of the daily tank, a large amount of mixed vapor will be discharged into the atmosphere. When the transfer pump of the methanol storage tank delivers methanol liquid to the daily tank, the liquid level drops and the pressure in the tank decreases. In order to maintain the pressure in the tank within a certain range, the inert gas is automatically added to the tank according to the pressure setting value. The above content is a common design of ships, which results in a large amount of methanol gas and inert gas being wasted, and the pressure relief valve of the daily cabinet and the automatic inert gas replenishment valve of the methanol storage tank are frequently opened and closed, which can easily cause damage.

[0005] To address this design shortcoming and avoid energy waste and valve damage, a complete and reliable system must be set up. The following solutions can solve this problem:

[0006] 1. Add ventilation pipes and stop valves to the top of the methanol daily cabinet and methanol storage tank respectively, and then connect the ventilation pipes;

[0007] 2. A branch pipe is built on the ventilation connecting pipe, and a compressed air-driven stop valve is installed. The outlet of the stop valve is connected to the deck ventilation column;

[0008] 3. The pressure sensor signal on the existing methanol daily cabinet is then transmitted to the solenoid valve control box. The control box drives the opening and closing of the solenoid valve according to the pressure sensor signal value (start / stop) to control the opening and closing of the compressed air, thereby controlling the pneumatic stop valve;

[0009] The above-mentioned clauses 1, 2, and 3 are requirements of the present invention. Such an arrangement can achieve pressure balance between the methanol daily cabinet and the methanol storage tank, recover a large amount of methanol gas, save a large amount of energy and inert gas waste, and avoid reducing the service life due to frequent driving of valve parts; in emergency or special circumstances, the pneumatic stop valve is automatically driven to open and close according to the set value of the pressure sensor of the methanol daily cabinet, and the mixed steam is discharged into the atmosphere, protecting the pressure in the cabin to be maintained within a certain range. Summary of the invention

[0010] In order to solve the above problems, the present invention provides a vapor recovery device for a methanol daily cabinet, and the technical solution adopted is:

[0011] A vapor recovery device for a methanol daily cabinet, wherein a methanol fuel daily tank is provided with a daily tank air vent, a methanol storage tank top is provided with a storage tank air vent, a pressure balance pipeline is provided between the daily tank air vent and the storage tank air vent, one end of the pressure balance pipeline is connected to the air vent pipe on the top of the methanol fuel daily tank, and the other end is connected to the air vent pipe on the top of the methanol storage tank, the daily tank air vent is provided with a first stop valve, and the storage tank air vent is provided with a second stop valve.

[0012] A compressed air branch pipe extends out of the pressure balance pipeline, and a pneumatic stop valve is installed on the compressed air branch pipe. The inlet of the pneumatic stop valve is connected to the compressed air branch pipe, and the outlet is connected to the air permeable column. A pressure sensor is arranged on the top of the methanol fuel daily cabin. The pressure sensor transmits the signal to the solenoid valve control box, and the solenoid valve control box controls the pneumatic stop valve.

[0013] The vapor recovery device of the methanol daily cabinet mentioned above further comprises a ventilation column located above the deck.

[0014] The vapor recovery device of the methanol daily cabinet mentioned above further comprises a fireproof net disposed on the top of the air-permeable column.

[0015] The vapor recovery device of the above-mentioned methanol daily cabinet further has the methanol fuel daily tank and the methanol storage tank both connected to the inert gas through an inert gas automatic air supply valve.

[0016] The vapor recovery device of the above-mentioned methanol daily cabinet further comprises a daily tank pressure vacuum release valve disposed on the top of the methanol fuel daily tank, and a storage tank pressure vacuum release valve disposed on the top of the methanol storage tank.

[0017] The vapor recovery device of the above-mentioned methanol daily cabinet further has a pressure sensor setting value of 0.35 kpa.

[0018] The beneficial effects of the present invention are:

[0019] When the methanol storage tank transfer pump injects methanol liquid into the methanol daily tank, there will be no pressure drop or vacuum in the methanol storage tank, and there is no need to add inert gas to the tank; there will be no pressure increase in the methanol daily tank due to the increase of methanol liquid and a large amount of volatile methanol gas, and the pressure will not be released through the pressure relief valve after reaching a certain value, thus wasting a large amount of methanol gas; in emergency and special circumstances, the methanol storage tank and daily tank are ensured to be within a safe pressure range.

[0020] On the one hand, the device of the present invention can solve the problems of excessive pressure generated when liquid is injected into the daily methanol fuel tank, causing the pressure relief valve to open and close frequently, and the automatic air replenishment valve to be easily damaged due to frequent inert gas replenishment in the methanol storage tank; on the other hand, the vapor of the daily methanol cabinet is recovered to the storage tank, avoiding the waste of methanol energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0022] Among them, A-methanol fuel daily tank, B-methanol storage tank, C-ventilation column, D-deck;

[0023] 1- Daily cabin pressure vacuum release valve, 2- Pressure sensor, 3- First stop valve, 4- Pressure balance pipeline, 5- Compressed air branch pipe, 6- Pneumatic stop valve, 7- Second stop valve, 8- Fire net, 9- Storage cabin pressure vacuum release valve, 10- Solenoid valve control box, 11- Inert gas automatic air supply valve. DETAILED DESCRIPTION

[0024] The present invention will be further described in conjunction with the accompanying drawings.

[0025] like Figure 1 The vapor recovery device of a methanol daily cabinet includes a pressure balance pipeline 4 between a methanol fuel daily tank A and a methanol storage tank B, and transmits the pressure signal in the tank to a solenoid valve control box 10; the solenoid valve controls compressed air to drive the pneumatic stop valve 6 to open and close, and discharges steam to reduce the pressure in the tank. The methanol fuel daily tank is provided with a daily tank air vent, and the top of the methanol storage tank is provided with a storage tank air vent. A pressure balance pipeline is provided between the daily tank air vent and the storage tank air vent, one end of the pressure balance pipeline is connected to the air vent pipe on the top of the methanol fuel daily tank, and the other end is connected to the air vent pipe on the top of the methanol storage tank, the daily tank air vent is provided with a first stop valve 3, and the storage tank air vent is provided with a second stop valve 7.

[0026] A compressed air branch pipe 5 extends out of the pressure balance pipeline, and a pneumatic stop valve 6 is installed on the compressed air branch pipe. The inlet of the pneumatic stop valve is connected to the compressed air branch pipe, and the outlet is connected to the air-permeable column C. A pressure sensor 2 is provided on the top of the methanol fuel daily cabin. The pressure sensor transmits the signal to the solenoid valve control box 10, and the solenoid valve control box controls the pneumatic stop valve 6.

[0027] When the low liquid level switch signal of methanol daily tank A is sent to the transfer pump in methanol storage tank B, the pump automatically starts to transport methanol liquid to the daily tank, the liquid level of methanol daily tank A rises, the volatile gas of methanol increases, and the excess methanol vapor passes through the breather valve 3, the breather pipe 4, the breather valve 7 of methanol storage tank B, and reaches the methanol storage tank B, thus balancing the vapor pressure of the two methanol tanks.

[0028] When the volatile gas in the methanol daily cabinet A is too high, such as in the hot summer, methanol is highly volatile and the methanol storage tank B cannot store a large amount of vapor, or the methanol ventilation pipe 4 has a long pipeline and large resistance, the pressure in the methanol daily cabinet A continues to rise and reaches the set value of the pressure sensor 2 (such as 0.35kpa), the signal is sent to the control box 10, the solenoid valve is opened, and the alarm is output to the control console at the same time, and the compressed air drives the stop valve 6 to start through the pipeline 5, opens the valve to discharge the vapor to the ventilation column C, and then passes through the fireproof net 8 to discharge the excess vapor into the atmosphere.

Claims

1. A vapor recovery device for a methanol daily cabinet, characterized in that: The methanol fuel daily tank (A) is provided with a daily tank vent, the top of the methanol storage tank (B) is provided with a storage tank vent (), a pressure balance pipeline (4) is provided between the daily tank vent and the storage tank vent, one end of the pressure balance pipeline is connected to the vent pipe on the top of the methanol fuel daily tank, and the other end is connected to the vent pipe on the top of the methanol storage tank, the daily tank vent is provided with a first stop valve (3), and the storage tank vent is provided with a second stop valve (7); A compressed air branch pipe (5) extends out of the pressure balance pipeline, and a pneumatic stop valve (6) is installed on the compressed air branch pipe. The inlet of the pneumatic stop valve is connected to the compressed air branch pipe, and the outlet is connected to the air permeable column (C). A pressure sensor (2) is arranged on the top of the methanol fuel daily cabin. The pressure sensor transmits a signal to the solenoid valve control box (10), and the solenoid valve control box controls the pneumatic stop valve.

2. The vapor recovery device of a methanol daily cabinet according to claim 1, characterized in that: The ventilation columns are located above the deck (D).

3. The vapor recovery device of a methanol daily cabinet according to claim 1, characterized in that: A fireproof net (8) is arranged on the top of the ventilation column.

4. The vapor recovery device of a methanol daily cabinet according to claim 1, characterized in that: The methanol fuel daily tank and the methanol storage tank are both connected to the inert gas via an inert gas automatic air supply valve (11).

5. The vapor recovery device of a methanol daily cabinet according to claim 1, characterized in that: A daily cabin pressure vacuum release valve (1) is arranged on the top of the methanol fuel daily cabin, and a storage cabin pressure vacuum release valve (9) is arranged on the top of the methanol storage cabin.

6. The vapor recovery device of a methanol daily cabinet according to claim 1, characterized in that: The pressure sensor setting value is 0.35kpa.

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