CN-121553345-B - BOG recondensing system based on high-pressure cold energy utilization

CN121553345BCN 121553345 BCN121553345 BCN 121553345BCN-121553345-B

Abstract

The invention provides a BOG recondensing system based on high-pressure cold energy utilization, which comprises a fuel tank, a BOG compression unit, a BOG recondensing unit, a low-pressure fuel supply unit and a user supply path, wherein the BOG compression unit is connected with the fuel tank and is used for compressing BOG volatilized in the fuel tank, the BOG recondensing unit is connected with the BOG compression unit and is used for condensing compressed BOG for recycling, the fuel supply path is connected between the fuel tank and the BOG recondensing unit and is used for conveying fuel in the fuel tank to the BOG recondensing unit and condensing the compressed BOG, the user supply path is connected with the fuel supply path and is used for supplying fuel to a low-pressure user, and the high-pressure fuel supply unit is connected with the BOG recondensing unit and is used for supplying the fuel passing through the BOG recondensing unit to the high-pressure user.

Inventors

ZHOU BAOYU
Gong Rongyu
GONG PENG
DONG SANGUO
ZHANG CHENGYOU
ZHANG PENGPENG
LIANG BOHAN
LI TIANJIE

Assignees

江南造船(集团)有限责任公司

Dates

Publication Date: 20260508
Application Date: 20260122

Claims (11)

1. A BOG recondensing system based on high pressure cold energy utilization, comprising: A fuel tank; the BOG compression unit is connected with the fuel cabin and used for compressing the volatilized BOG in the fuel cabin; the BOG recondensing unit is connected with the BOG compression unit and is used for condensing the compressed BOG for recycling; a low pressure fuel supply unit including a fuel supply path connected between the fuel tank and the BOG recondensing unit for delivering fuel in the fuel tank to the BOG recondensing unit to condense compressed BOG, and a user supply path connected to the fuel supply path to supply fuel to a low pressure user; A high pressure fuel supply unit connected to the BOG recondensing unit for supplying fuel passing through the BOG recondensing unit to a high pressure user; The BOG recondensing unit comprises a pre-condenser and a recondensor, a first inlet of the pre-condenser is connected with the BOG compression unit, a first outlet of the pre-condenser and the fuel supply path are respectively connected with a first inlet and a second inlet of the recondensor, the system further comprises a non-condensable gas treatment unit, an outlet of the recondensor is connected with an inlet of the non-condensable gas treatment unit, and the non-condensable gas treatment unit is connected with the high-pressure fuel supply unit; The high-pressure fuel supply unit comprises a recondensing supply valve, a high-pressure pump and a high-pressure vaporizer, wherein the inlet of the high-pressure pump is connected with the outlet of the non-condensable gas treatment unit through the recondensing supply valve, the outlet of the high-pressure pump is connected with the second inlet of the pre-condenser, and the second outlet of the pre-condenser is connected with the high-pressure vaporizer.
2. The BOG recondensing system based on high-pressure cold energy utilization according to claim 1, wherein the BOG compression unit comprises a preheater, a gas-liquid separation tank and a compressor skid block, wherein the preheater, the gas-liquid separation tank and the compressor skid block are sequentially connected, an inlet of the preheater is connected with the fuel tank, on-off is controlled between the inlet of the preheater and the fuel tank through a compression unit control valve, an outlet of the compressor skid block is divided into two branches, one branch is connected with the BOG recondensing unit, and the other branch is connected with the user supply path so as to supply fuel to a low-pressure user.
3. The BOG recondensing system based on high pressure cold energy utilization of claim 1, wherein the fuel supply path comprises a low pressure pump, a duplex filter, and a high pressure fuel supply valve, the low pressure pump, the duplex filter, and the high pressure fuel supply valve being connected in sequence, the low pressure pump being connected to the fuel tank, the high pressure fuel supply valve being connected to the BOG recondensing unit.
4. The BOG recondensing system based on high pressure cold energy utilization of claim 1, further comprising a back-tank line connected between the BOG recondensing unit and the fuel tank for flowing condensed BOG back to the fuel tank.
5. The BOG recondensing system based on high-pressure cold energy utilization according to claim 1, wherein the non-condensable gas treatment unit is provided with a non-condensable gas release pipeline, a gas release valve is arranged on the non-condensable gas release pipeline, an outlet of the gas release valve is divided into two branches, one branch is used for being connected with a ventilation system, a gas ventilation valve is arranged on the branch, the other branch is connected with the BOG compression unit, and a gas circulation valve is arranged on the branch.
6. The BOG recondensing system based on high-pressure cold energy utilization according to claim 1, wherein the user supply path comprises a low-pressure fuel supply valve, a straight-through control valve, a low-pressure fuel throttle valve, a non-condensable gas treatment control valve, a low-pressure vaporizer and a low-pressure buffer tank, an inlet of the low-pressure fuel supply valve is connected to the fuel supply path, an outlet of the low-pressure fuel supply valve is divided into two branches, one branch is sequentially provided with the straight-through control valve, the low-pressure vaporizer and the low-pressure buffer tank, the other branch is sequentially connected with the low-pressure fuel throttle valve and the non-condensable gas treatment control valve, and the branch is connected between the straight-through control valve and the low-pressure vaporizer after passing through the non-condensable gas treatment unit.
7. The BOG recondensing system based on high pressure refrigeration energy utilization of claim 6, wherein an outlet of said low pressure fuel throttle valve splits into two branches, one branch connected to said non-condensable gas treatment control valve and the other branch connected to a third inlet of said pre-condenser, a third outlet of said pre-condenser connected between said pass-through control valve and said low pressure vaporizer.
8. The BOG recondensing system based on high pressure refrigeration energy utilization of claim 1, wherein a first outlet of said pre-condenser is connected to a first inlet of said recondensing device by one of the outlets of a three-way control valve, and further comprising a hold back line, and wherein the other outlet of said three-way control valve is connected to said fuel tank by said hold back line.
9. The BOG recondensing system based on high-pressure cold energy utilization according to claim 8, wherein a supercooling degree differential pressure indicator is arranged at an outlet of the pre-condenser, the supercooling degree differential pressure indicator is used for sending a signal to the three-way control valve, and the three-way control valve controls the flow direction of the BOG based on the supercooling degree differential pressure indicator.
10. The BOG recondensing system based on high pressure cold energy utilization of claim 5, wherein said non-condensable gas treatment unit is provided with a pressure sensor for sending a signal to said gas release valve to control the opening and closing of said gas release valve.
11. The BOG recondensing system based on high pressure cold energy utilization of claim 1, wherein said non-condensable gas treatment unit is provided with a liquid level sensor for sending a signal to said recondensing supply valve, said recondensing supply valve being opened and closed based on said liquid level sensor for supplying fuel to said high pressure pump.

Description

BOG recondensing system based on high-pressure cold energy utilization Technical Field The invention relates to the technical field of BOG condensation, in particular to a BOG recondensing system based on high-pressure cold energy utilization. Background Current marine emissions account for 3% of the total carbon emissions worldwide, with the marine industry facing severe emissions reduction pressures. In this context the vessel power needs to achieve zero carbon conversion. Currently, the air supply pressure of a dual-fuel high-pressure host machine is as high as 300-380 barg (LNG: 300-325 barg, LEG:380 barg), the pressure of a fuel tank is generally 0.7-4.5 barg, and flash vapor (BOG) generated in the tank cannot be directly supplied to the host machine. The conventional BOG treatment method comprises the following steps of firstly, pressurizing the BOG by a high-pressure BOG compressor to meet the requirement of a host, wherein the price of the high-pressure BOG compressor is relatively expensive, and the range of a manufacturer which can select the high-pressure BOG compressor is relatively narrow, secondly, pressurizing the BOG by a low-pressure BOG compressor and then supplying the BOG to a dual-fuel generator or a boiler, wherein if the BOG is burnt by adopting a GCU mode of the boiler, fuel energy is wasted, the method is not applicable to many shipments which only add the dual-fuel host, thirdly, a supercooling unit (Subcooler) is arranged to cool a fuel cabin so as to convert the BOG in the fuel cabin into liquid, or a BOG recondensing system is added to send the BOG to the fuel cabin or directly supply the BOG to the host through a pump, and a set of system is additionally added by the method, so that the cost and the energy consumption are relatively large. In addition, taking LNG as an example, LNG at 4.5Barg corresponds to a saturation temperature of about-135 ℃ and is vaporized only when pressurized to 300Barg to-70 ℃, and there is an unused subcooling amount. With the full use of high-pressure hosts, recovering the cold energy available after pressurization by the pump becomes a critical path for improving the energy efficiency of the ship. CN120351081a discloses a BOG recondensing system of a dual fuel vessel, comprising a BOG pretreatment unit, a BOG recondensing unit, a low pressure gas supply unit and a high pressure gas supply unit. The BOG pretreatment unit comprises a BOG preheater, a BOG suction port tank, a compressor, a first-stage oil-gas separator, a BOG aftercooler and a second-stage oil-gas separator which are sequentially connected, the recondensing unit comprises a second-stage oil-gas separator, a BOG precooler, a high-pressure pump and a high-pressure gasifier which are sequentially connected, the low-pressure gas supply unit comprises a low-pressure pump arranged in a fuel tank, a gas duplex filter, a BOG recondenser and a high-pressure pump which are sequentially connected with an outlet of the low-pressure pump, and the high-pressure gas supply unit comprises a high-pressure gasifier, a BOG precooler, a high-pressure gas buffer tank, an engine gas supply main valve group and an engine which are sequentially connected with an outlet of the high-pressure pump. The invention can realize recondensing of BOG, and recondensed liquid can be returned to a fuel tank through a control valve or mixed into a high-pressure pump to prepare fuel. The method has the following defects that recondensed liquid is returned to a fuel tank or enters a high-pressure pump to be switched and judged only by human experience, a recondensing system lacks an automatic and scientific operation mode switching means, a fixed compressor is an oil compressor at normal temperature, only cost factors are considered to limit system design flexibility, and the risk of damage to the high-pressure pump due to oil gas icing exists, the superpressure fuel gas in the BOG recondenser and non-fuel non-condensable gas are not distinguished, the direct gas is sent to the compressor to be treated again, the problems that the design is complex, the occupied space is large, the treatment efficiency is poor and the like exist in the container type BOG recondenser, the recondenser is not beneficial to controlling the pressure of the fuel tank due to the fact that the liquid is gasified again after depressurization in the fuel tank returning process caused by the supercooling means are not considered, and the application of the recondensed system in the ammonia fuel supply system is omitted by the methane and ethane fuel supply system. Disclosure of Invention In view of the above-described drawbacks of the related art, an object of the present invention is to provide a BOG recondensing system based on high pressure cold energy utilization. To achieve the above and other related objects, the present invention provides a BOG recondensing system based on high pressure cold energy utilization, comprising a fuel tank, a BOG com