Process and device for carrying out power generation by virtue of cascade cold energy of liquefied natural gas

Abstract

The invention discloses a process and a device for carrying out power generation by virtue of the cascade cold energy of liquefied natural gas. The process for power generation comprises the following steps: the low-pressure liquefied natural gas from an LNG storage tank is divided into two paths, one path enters a submerged combustion vaporizer through a high-pressure conveying pump of an LNG receiving station to be gasified and then is conveyed outwards through an outward conveying tube network; the other path of the low-pressure liquefied natural gas from the LNG storage tank is pressurized into high-pressure LNG through the high-pressure conveying pump, and the high-pressure LNG enters a first-stage Rankine cycle and a second-stage Rankine cycle respectively, so as to assist the first-stage Rankine cycle and the second-stage Rankine cycle to generate power; and then the high-pressure LNG is gasified into gaseous-state natural gas, enters the natural gas outward conveying tube network, and is combined with the natural gas from the submerged combustion vaporizer and then conveyed outwards. According to the invention, a power generation system with two-stage transversal Rankine cycles is used for power generation; the LNG outward conveying high-pressure pump and an air-temperature vaporizer are arranged independently, thus consideration can also be given to the need of peak regulation of the LNG receiving station, and the operation is flexible and convenient. Power generation is carried out by virtue of the cold energy of the LNG, and the energy-saving effect is more prominent.

Description

technical field [0001] The invention relates to the field of generating electricity by utilizing the cold energy of natural gas, in particular to a process and a device for generating electricity by utilizing the cascaded cold energy of liquefied natural gas. Background technique [0002] Due to its high efficiency, high quality, clean performance and wide range of uses, natural gas has become a safe and clean energy that is generally favored by countries all over the world. After liquefaction, the volume of natural gas is reduced to 1 / 600 of its original volume, which is convenient for long-distance transportation. After the LNG is transported to the station by ship, it needs to convert the liquid LNG into a gaseous state, releasing about 830-860MJ / t of cold energy during the process. The traditional method is to use LNG is gasified directly through the seawater vaporizer (ORV), and a large amount of cold energy is taken away by the seawater without being used, especially i...

AI Technical Summary

Problems solved by technology

After liquefaction, the volume of natural gas is reduced to 1 / 600 of its original volume, which is convenient for long-distance transportation. After the LNG is transported to the station by ship, it needs to convert the liquid LNG into a gaseous state, releasing about 830-860MJ / t of cold energy during the process. The traditional method is to use LNG is gasified directly through the seawater vaporizer (ORV), and a large amount of cold energy is taken away by the seawater without being used, especially in poor seawater quality or LNG receiving stations in inland areas often use submerged combustion vaporizers (SCV) for gasification. LNG gasification not only causes waste of LNG cold energy, but also increases the use of LNG as fuel, resulting in a huge waste of energy

Images