Dual-fuel engine LNG supply system and LNG ship

Abstract

The invention provides a dual-fuel engine LNG supply system. The dual-fuel engine LNG supply system comprises an LNG vaporizer, an NG heater, a circulating pump, a first heater, a second heater, a first three-way adjusting valve, a second three-way adjusting valve, an LNG inlet pipeline, an NG outlet pipeline, a hot water inlet pipeline, a hot water outlet pipeline, a steam inlet pipeline and a steam outlet pipeline. The LNG inlet pipeline communicates with an LNG inlet of the LNG vaporizer. An NG outlet of the LNG vaporizer communicates with an NG inlet of the NG heater. An NG outlet of the NG heater communicates with the NG outlet pipeline. According to the dual-fuel engine LNG supply system, the compatibility of the gas supply system is improved, LNG vaporization heating can be conducted through multiple heat sources, meanwhile, the self-adjusting capacity of the gas supply system is improved, and accordingly the situation that the temperature and flow of the heat sources or the host load is changed is handled. The invention further provides an LNG ship.

Description

technical field [0001] The invention relates to the technical field of ship engine gas supply, in particular to a dual-fuel engine LNG gas supply system and an LNG ship. Background technique [0002] With the deterioration of the global environment, the pollution of the atmosphere caused by exhaust emissions from ships has attracted widespread attention from the international community. Faced with various restrictions of maritime regulations, ship engines have begun to take various improvement measures to reduce exhaust emissions. The dual-fuel engine is favored by domestic and foreign shipowners due to its good emission, power and economy. Compared with the auxiliary system of the traditional low-speed diesel engine, the dual-fuel engine needs to add a natural gas supply system to supply the dual-fuel main engine. Gas fuel that meets the requirements of gas supply pressure and gas supply temperature. [0003] The dual-fuel engine LNG (Liquefied Natural Gas, liquefied natu...

AI Technical Summary

Problems solved by technology

[0004] In the existing process, the dependence of the water glycol circulation system on the heat source is relatively obvious. Due to the limited adjustment ability of the water glycol circulation system itself, when the temperature and flow of the heat source change or when the host load increases (the supply flow of LNG increase accordingly), the temperature of the water glycol at the outlet of the vaporizer is easy to drop rapidly in a short time, if the temperature is too low, it will cause the nozzle to frost, if the nozzle is kept at low temperature for a long time, the pipeline will cause safety hazards such as rupture

At the same time, the types of heat sources in some processes are single, and the water glycol circulation system cannot be compatible with multiple heat sources

There are also some processes that can be compatible with multiple heat sources, but this part of the process adopts a primary heat exchange method, that is, directly uses the heat source to exchange heat with LNG. This primary heat exchange method is prone to condensation and freezing of the pipeline (ie Directly use hot water or steam to exchange heat with LNG, because the freezing point of water is relatively high, so it is easy to freeze)

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