Waste heat utilization system suitable for waste heat energy recovery of low-speed marine engine

Abstract

The invention discloses a waste heat utilization system suitable for waste heat energy recovery of a low-speed marine engine. The waste heat utilization system comprises a high-temperature organic Rankine cycle subsystem and a low-temperature organic Rankine cycle subsystem. An air cooler in the system is designed in two segments being a high-temperature segment and a low-temperature segment. Thehigh-temperature organic Rankine cycle subsystem recovers engine exhaust and scavenging air energy through a waste gas heat exchanger, a superheater, an evaporator, a preheater and the high-temperature segment of the air cooler to generate daily steam and output electricity. The low-temperature organic Rankine cycle subsystem recovers jacket cooling water and scavenging air energy through a jacketwater cooler and the low-temperature segment of the air cooler to output electricity. According to the waste heat utilization system, acid corrosion of the heat exchanger surface in the waste heat utilization system can be effectively avoided when the engine is running at low load, the reasonable, safe and effective use of waste heat energy in the range of all working conditions of the engine canbe realized, the thermal efficiency of a ship power system is significantly improved, and EEDI is reduced.

Description

Technical field [0001] The invention relates to the technical field of waste heat utilization, in particular to a waste heat utilization system suitable for waste heat energy recovery of low-speed marine engines. Background technique [0002] Energy is an indispensable resource in people's life and development, and an important material basis for economic development and human society. Approximately 90% of the world's trade is completed by sea transportation, and as a transportation tool with huge energy consumption, the high energy consumption of ships has caused the increase of ship operating costs and environmental pollution problems. With the urgent need for energy saving and emission reduction of ships and the deteriorating marine environment, the International Maritime Organization (IMO) has proposed the EEDI (EnergyEfficiency Design Index, new ship energy efficiency design index) implementation form, which stipulates that the EEDI reduction factor will be reduced after 202...

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Problems solved by technology

In the range of common working conditions of marine low-speed engines, the exhaust temperature fluctuates between 200°C and 250°C, the boosted air increases linearly between 30°C and 200°C, and the cylinder liner cooling water is basically a constant temperature heat source to 90°C. From low load to high load, the proportion of the first two gradually increases, but at low and medium loads, low-grade energy accounts for a relatively large proportion of the total energy loss. Therefore, how to improve the conversion of low-load waste heat energy in low-speed marine engines is a problem. major problem

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