CN117846839A - Methanol fuel double-wall pipe ventilation system and control method - Google Patents

Abstract

The invention provides a methanol fuel double-wall pipe ventilation system and a control method, wherein the methanol fuel double-wall pipe ventilation system comprises an exhaust fan, a gas detector, a liquid level switch, a heater and the like, when methanol fuel is conveyed, a pipeline after entering a cabin adopts a double-wall pipe structure, and an exhaust fan is arranged in annular gaps between the inner pipe and the outer pipe of the double-wall pipe for mechanical ventilation, so that the risk of leakage of fuel gas to the cabin is avoided, and the negative pressure requirement of annular gap ventilation between the inner pipe and the outer pipe can be met. Meanwhile, methanol is liquid at normal temperature, when the inner pipe of the double-wall pipe is leaked, the methanol can leak into the annular gap in a liquid form, the methanol is collected through the methanol collecting cavity and combined with the heater to heat the liquid methanol into gas, and then an exhaust fan is arranged through the annular gap to perform mechanical ventilation, so that the gas is discharged, the safe and reliable use of methanol fuel is ensured, and the occurrence of potential risks is avoided.

Description

Methanol fuel double-wall pipe ventilation system and control method

Technical Field

The invention relates to the technical field of ship construction, in particular to a methanol fuel double-wall pipe ventilation system and a control method.

Background

With the rapid development of the ship shipping industry in recent years, the problem of marine pollution is increasingly serious, and untreated waste gas is discharged into the atmosphere in a large amount, so that serious damage is caused to the marine and even global ecological environment. In order to reduce pollution of marine exhaust gas to the environment, the international maritime organization has proposed specific emission restrictions, and it is desired to improve the ecological environment of the ocean by revising the emission restrictions. In order to adapt to the change of emission limit, ships begin to adopt cleaner green energy to replace traditional energy, methanol is one of selectable green fuels, and a dual-fuel engine taking methanol as a main fuel is widely applied in the field of ships.

Because the characteristic of inflammability and explosiveness of the gas fuel, in order to ensure the running safety of the ship, the cabin of the ship is divided into safety areas according to the standard requirements, and a plurality of potential safety hazards exist when the single-wall pipe is used for supplying fuel gas to the engine of the cabin, and the requirement of dividing the cabin into the safety areas is not met.

Disclosure of Invention

In view of the above-described drawbacks of the prior art, the present invention provides a methanol fuel double-wall pipe ventilation system including:

the methanol dual-fuel host is arranged in the cabin, the fuel used by the methanol dual-fuel host comprises methanol or fuel oil, and the methanol dual-fuel host works in a methanol mode or a fuel oil mode according to the fuel used;

the inlet interface and the outlet interface of the methanol dual-fuel host are respectively connected with a liquid inlet pipe and a liquid outlet pipe, the liquid inlet pipe and the liquid outlet pipe are double-wall pipes, the double-wall pipes comprise an inner pipe and an outer pipe, and an annular gap is formed between the inner pipe and the outer pipe; the inner pipe of the liquid inlet pipe is used for supplying methanol, and the inner pipe of the liquid outlet pipe is used for discharging the unburned methanol;

the port of the liquid inlet pipe far away from the methanol dual-fuel host is positioned outside the engine room and is connected with a compressed air interface for sending dry compressed air to an annular gap of the liquid inlet pipe to provide ventilation air.

Preferably, a flowmeter is arranged between the compressed air interface and the liquid inlet pipe end and is used for on-line monitoring of the flow rate of the compressed air flowing into the liquid inlet pipe.

Preferably, a control valve is arranged between the flowmeter and the inlet pipe end and used for adjusting the compressed air flow, the control valve is connected with a control interface, and the control interface is used for controlling the opening degree of the control valve.

Preferably, a check valve is arranged between the control valve and the inlet pipe end to prevent the compressed air from flowing back.

Preferably, the liquid inlet pipe end is also provided with a flow switch, the flow switch sets a lower limit value, and when the flow of compressed air in the pipeline reaches the lower limit value, the flow switch sends out a signal and adjusts the opening of the control valve or the compressed air at the compressed air interface through the control interface, so that the compressed air supply quantity of the system is increased.

Preferably, the port of the liquid outlet pipe far away from the methanol dual-fuel main engine is positioned outside the engine room and is connected with an exhaust fan so as to exhaust methanol gas in the annular gap.

Preferably, a gas detector is arranged at a port of the liquid outlet pipe far away from the methanol dual-fuel host machine, and is used for detecting whether methanol gas leaks in the annular gap of the double-wall pipe, if so, giving an alarm, and the methanol dual-fuel host machine is switched from a methanol mode to a fuel mode and stops the methanol supply of the liquid inlet pipe.

Preferably, a methanol collecting cavity is arranged below the lowest point of the liquid outlet pipe, and the methanol collecting cavity is communicated with the annular gap of the liquid outlet pipe so as to collect liquid methanol in the annular gap.

Preferably, the methanol collecting cavity is provided with a heater, when liquid in the annular gap is converged to the methanol collecting cavity, the heater is automatically started to heat the methanol to a temperature above 65 ℃, and at the moment, the methanol liquid can be evaporated to become gas so as to be helpful for an exhaust fan at the port of the liquid outlet pipe to discharge the methanol liquid;

the methanol collecting cavity is also provided with a liquid level switch, when methanol exists in the methanol collecting cavity, the liquid level switch can give an alarm, and meanwhile, the heater can be automatically triggered to heat, and the methanol host is switched from a methanol mode to a fuel mode.

The invention also provides a control method of the methanol fuel double-wall pipe ventilation system, which comprises the following steps:

s1: when the methanol dual-fuel host works in a methanol mode, the exhaust fan keeps exhausting, the compressed air interface keeps supplying compressed air, and no methanol gas is accumulated in the annular gaps of the liquid inlet pipe and the liquid outlet pipe;

s2: when the gas detector detects that methanol gas exists in the annular gap of the double-wall pipe, an alarm is given, and the air draft fan continues to draft air to pump the methanol gas out of the annular gap; simultaneously, the methanol dual-fuel host is switched from a methanol mode to a fuel mode, and the methanol supply of the liquid inlet pipe is stopped;

s3: when there is the methyl alcohol of leakage in the methyl alcohol collecting chamber, the liquid level switch can give the warning, and the while heater self-heating heats the methyl alcohol to more than 65 degrees, and methyl alcohol becomes gas by liquid, and the air exhauster continues the convulsions, takes out annular clearance with the methyl alcohol gas, and simultaneously the host computer is switched to the fuel mode by the methyl alcohol mode.

As described above, the invention provides a methanol fuel double-wall pipe ventilation system and a control method thereof. And meanwhile, if liquid leaks, methanol liquid is heated into gas by heating, and then the annular space between the inner pipe and the outer pipe is ventilated, so that the gas is discharged, and the methanol gas is prevented from leaking to the engine room. The invention improves the safety of system design and avoids the occurrence of potential risks.

Drawings

Fig. 1 shows a schematic system structure of a methanol fuel double-wall pipe ventilation system of the invention.

Description of element reference numerals

101. Flowmeter for measuring flow rate

102. Control valve

103. Check valve

104. Flow switch

105. Inlet interface

106. Outlet interface

107. Double-wall pipe

108. Heater

109. Methanol collecting cavity

110. Liquid level switch

111. Pressure gauge

112. Gas detector

113. Air draft fan

201. Compressed air interface

202. Control interface

203. Methanol dual-fuel main engine

204. Cabin

301. Inner pipe

302. Outer tube

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

As described in detail in the embodiments of the present invention, the cross-sectional view of the device structure is not partially enlarged to a general scale for convenience of explanation, and the schematic drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.

For ease of description, spatially relative terms such as "under", "below", "beneath", "above", "upper" and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Furthermore, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers or one or more intervening layers may also be present. As used herein, "between … …" is meant to include both endpoints.

In the context of this application, a structure described as a first feature being "on" a second feature may include embodiments where the first and second features are formed in direct contact, as well as embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of each component in actual implementation may be changed at will, and the layout of the components may be more complex.

As shown in fig. 1, the present invention provides a methanol fuel double-wall pipe ventilation system, which specifically includes:

a methanol dual-fuel main engine 203, wherein the methanol dual-fuel main engine 203 is arranged in a cabin 204, the used fuel comprises methanol or fuel oil, and the methanol dual-fuel main engine 203 works in a methanol mode or a fuel oil mode according to the used fuel;

the inlet interface 105 and the outlet interface 106 of the methanol dual-fuel host 203 are respectively connected with a liquid inlet pipe and a liquid outlet pipe, the liquid inlet pipe and the liquid outlet pipe are both double-wall pipes 107, the double-wall pipes 107 comprise an inner pipe 301 and an outer pipe 302, and an annular gap is formed between the inner pipe 301 and the outer pipe 302. The inner tube 301 of the liquid inlet pipe is used for supplying methanol, and the inner tube 301 of the liquid outlet pipe is used for discharging the unburned methanol.

Further, a port of the liquid inlet pipe far away from the methanol dual-fuel main engine 203 is positioned outside the engine room 204 and is connected with a compressed air interface 201 for sending dry compressed air to an annular gap of the liquid inlet pipe to provide ventilation air;

further, a flowmeter 101 is arranged between the compressed air interface 201 and the inlet pipe end, and is used for on-line monitoring of the flow rate of the compressed air flowing into the inlet pipe; a control valve 102 is arranged between the flowmeter 101 and the inlet pipe end and used for adjusting the compressed air flow, the control valve 102 is connected with a control interface 202, and the control interface 202 is used for controlling the opening degree of the control valve 102; a check valve 103 is arranged between the control valve 102 and the inlet pipe end to prevent the compressed air from flowing back.

Further, a flow switch 104 is further disposed at the inlet pipe end, the flow switch 104 sets a lower limit value, and when the flow of compressed air in the pipeline reaches the lower limit value, the flow switch 104 sends out a signal and adjusts the opening of the control valve 102 or the compressed air at the compressed air interface 201 through the control interface 202, so as to increase the compressed air supply amount of the system.

Further, the port of the liquid outlet pipe far away from the methanol dual-fuel host 203 is located outside the engine room 204 and is connected with an exhaust fan 113, so as to exhaust the methanol gas in the annular gap of the liquid outlet pipe, and ensure that no methanol gas is accumulated in the annular gap of the double-wall pipe 107.

The liquid inlet pipe and the liquid outlet pipe are both double-wall pipes 107, so that methanol in the inner pipe 301 is prevented from being directly dispersed into the engine room 204 when leaking, and a dangerous source is limited in the annular gap. Meanwhile, the ports of the liquid inlet pipe and the liquid outlet pipe are arranged outside the engine room 204, so that dangers caused by methanol entering the engine room 204 through the ports are avoided. The compressed air at the inlet pipe port can provide ventilation air to further promote the discharge of methanol in the annular gap.

Further, a gas detector 112 is disposed at a port of the liquid outlet pipe far away from the methanol dual-fuel host 203, and is used for detecting whether methanol gas leaks in the annular gap of the double-wall pipe 107, if so, giving an alarm, the methanol dual-fuel host 203 is switched from a methanol mode to a fuel mode, the methanol supply of the liquid inlet pipe is stopped, and meanwhile, the air draft fan 113 can keep air draft. The suction fans 113 are configured in a 2x100% redundant design, arranged outside the nacelle 204 area, and the main machine is in a methanol mode, the fans keep ventilation, ensuring that no methanol gas accumulates in the annular gap of the double-walled tube 107.

Further, a pressure gauge 111 is connected to the annular gap of the outlet pipe to display the pressure in the pipe.

Further, a methanol collecting cavity 109 is arranged below the lowest point of the liquid outlet pipe, and the methanol collecting cavity 109 is communicated with the annular gap of the liquid outlet pipe so as to collect liquid methanol in the annular gap. The methanol collecting cavity 109 is provided with a heater 108, when liquid in the annular gap is converged to the methanol collecting cavity 109, the heater 108 is automatically started to heat the methanol to a temperature above 65 degrees (the boiling point of the methanol is 64.8 degrees), and the methanol liquid can be evaporated to become gas at the moment so as to be helpful for the exhaust fan to exhaust the methanol liquid. The methanol collecting cavity 109 is further provided with a liquid level switch 110, when methanol exists in the methanol collecting cavity 109, the liquid level switch 110 can give an alarm, meanwhile, the heater 108 can be automatically triggered to heat, the methanol host is switched to a fuel mode from a methanol mode, and meanwhile, the air draft fan 113 can continuously keep air draft. The design of the methanol collecting cavity 109 can collect liquid methanol better, and the methanol can be discharged rapidly by combining with the heating of the heater 108, so that the use safety is ensured.

Based on the double-wall pipe ventilation system, the application also provides a control method, which comprises the following steps:

s1: when the methanol dual-fuel host 203 works in the methanol mode, the air draft fan 113 keeps air draft, and the compressed air interface 201 keeps compressed air supply, so that no methanol gas is accumulated in the annular gaps of the liquid inlet pipe and the liquid outlet pipe;

s2: when the gas detector 112 detects that the methanol gas exists in the annular gap of the double-wall pipe 107, an alarm is given, and the air draft fan 113 continues to draft air to pump the methanol gas out of the annular gap; simultaneously, the methanol dual-fuel host 203 is switched from a methanol mode to a fuel mode, and the methanol supply of the liquid inlet pipe is stopped;

s3: when the leaked methanol exists in the methanol collecting cavity 109, the liquid level switch 110 gives an alarm, meanwhile, the heater 108 automatically heats the methanol to more than 65 ℃, the methanol is changed into gas from liquid, the air draft fan 113 continues to draft air, and the methanol gas is pumped out of the annular gap, so that the safety is ensured; at the same time the host switches from methanol mode to fuel mode.

In summary, the invention provides a methanol fuel double-wall pipe ventilation system and a control method, when methanol fuel is conveyed, a pipeline after entering a cabin adopts a double-wall pipe structure, and an exhaust fan is arranged in an annular gap between an inner pipe and an outer pipe of the double-wall pipe for mechanical ventilation, so that the risk of leakage of fuel gas to the cabin is avoided, and the negative pressure requirement of ventilation of the annular gap between the inner pipe and the outer pipe can be met. Meanwhile, methanol is liquid at normal temperature, when the inner pipe of the double-wall pipe is leaked, the methanol can leak into the annular gap in a liquid form, the methanol is collected through the methanol collecting cavity and combined with the heater to heat the liquid methanol into gas, and then an exhaust fan is arranged through the annular gap to perform mechanical ventilation, so that the gas is discharged, and the safe and reliable use of the methanol fuel is ensured.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (10)

1. A methanol fuel double-wall tube ventilation system, characterized in that the methanol fuel double-wall tube ventilation system comprises:

the methanol dual-fuel host is arranged in the cabin, the fuel used by the methanol dual-fuel host comprises methanol or fuel oil, and the methanol dual-fuel host works in a methanol mode or a fuel oil mode according to the fuel used;

the inlet interface and the outlet interface of the methanol dual-fuel host are respectively connected with a liquid inlet pipe and a liquid outlet pipe, the liquid inlet pipe and the liquid outlet pipe are double-wall pipes, the double-wall pipes comprise an inner pipe and an outer pipe, and an annular gap is formed between the inner pipe and the outer pipe; the inner pipe of the liquid inlet pipe is used for supplying methanol, and the inner pipe of the liquid outlet pipe is used for discharging the unburned methanol;

the port of the liquid inlet pipe far away from the methanol dual-fuel host is positioned outside the engine room and is connected with a compressed air interface for sending dry compressed air to an annular gap of the liquid inlet pipe to provide ventilation air.

2. The methanol fuel double wall tube ventilation system of claim 1, wherein: and a flowmeter is arranged between the compressed air interface and the liquid inlet pipe end and is used for on-line monitoring of the compressed air flow rate flowing into the liquid inlet pipe.

3. The methanol fuel double wall tube ventilation system of claim 2, wherein: a control valve is arranged between the flowmeter and the liquid inlet pipe end and used for adjusting the compressed air flow, the control valve is connected with a control interface, and the control interface is used for controlling the opening degree of the control valve.

4. A methanol fuel double wall tube ventilation system as in claim 3 wherein: and a check valve is arranged between the control valve and the liquid inlet pipe end to prevent the compressed air from flowing back.

5. A methanol fuel double wall tube ventilation system as in claim 3 wherein: the liquid inlet pipe end is also provided with a flow switch, the flow switch is provided with a lower limit value, and when the flow of compressed air in the pipeline reaches the lower limit value, the flow switch sends out a signal and adjusts the opening of the control valve or the compressed air at the compressed air interface through the control interface, so that the compressed air supply quantity of the system is increased.

6. The methanol fuel double wall tube ventilation system of claim 5, wherein: the port of the liquid outlet pipe far away from the methanol dual-fuel host is positioned outside the engine room and is connected with an exhaust fan so as to exhaust methanol gas in the annular gap.

7. The methanol fuel double wall tube ventilation system of claim 6, wherein: and a gas detector is arranged at a port of the liquid outlet pipe, which is far away from the methanol dual-fuel host, and is used for detecting whether methanol gas leaks in the annular gap of the double-wall pipe, if so, giving an alarm, and the methanol dual-fuel host is switched from a methanol mode to a fuel mode and stops the methanol supply of the liquid inlet pipe.

8. The methanol fuel double wall tube ventilation system of claim 7, wherein: the lower part of the lowest point of the liquid outlet pipe is provided with a methanol collecting cavity which is communicated with the annular gap of the liquid outlet pipe so as to collect liquid methanol in the annular gap.

9. The methanol fuel double wall tube ventilation system of claim 8, wherein: the methanol collecting cavity is provided with a heater, when liquid in the annular gap is converged to the methanol collecting cavity, the heater is automatically started to heat the methanol to a temperature above 65 ℃, and at the moment, the methanol liquid can be evaporated to become gas so as to be helpful for an exhaust fan at a liquid outlet pipe port to discharge the methanol liquid;

the methanol collecting cavity is also provided with a liquid level switch, when methanol exists in the methanol collecting cavity, the liquid level switch can give an alarm, and meanwhile, the heater can be automatically triggered to heat, and the methanol host is switched from a methanol mode to a fuel mode.

10. A method of controlling a methanol fuel double wall pipe ventilation system as claimed in claim 9, comprising the steps of:

s1: when the methanol dual-fuel host works in a methanol mode, the exhaust fan keeps exhausting, the compressed air interface keeps supplying compressed air, and no methanol gas is accumulated in the annular gaps of the liquid inlet pipe and the liquid outlet pipe;

s2: when the gas detector detects that methanol gas exists in the annular gap of the double-wall pipe, an alarm is given, and the air draft fan continues to draft air to pump the methanol gas out of the annular gap; simultaneously, the methanol dual-fuel host is switched from a methanol mode to a fuel mode, and the methanol supply of the liquid inlet pipe is stopped;

s3: when there is the methyl alcohol of leakage in the methyl alcohol collecting chamber, the liquid level switch can give the warning, and the while heater self-heating heats the methyl alcohol to more than 65 degrees, and methyl alcohol becomes gas by liquid, and the air exhauster continues the convulsions, takes out annular clearance with the methyl alcohol gas, and simultaneously the host computer is switched to the fuel mode by the methyl alcohol mode.