A transcritical carbon dioxide energy storage system and method based on utilization of lng cold capacity

Abstract

The invention discloses a cross-critical carbon dioxide energy storage system and method based on utilization of LNG cold energy utilization. The system comprises a carbon dioxide circulation loop; the carbon dioxide circulating loop comprises a liquid carbon dioxide gas storage tank, a first heat exchanger, a second heat exchanger, a compression unit, a supercritical carbon dioxide storage tank and an expansion unit; the outlet of the liquid carbon dioxide storage tank is connected with the inlet of the supercritical carbon dioxide storage tank through the evaporation side of the first heat exchanger and the compression unit; the outlet of the supercritical carbon dioxide storage tank is connected with the inlet of the liquid carbon dioxide air storage tank sequentially through the expansion unit, the condensation side of the first heat exchanger and the condensation side of the second heat exchanger; the evaporation side inlet of the second heat exchanger is connected with an LNG storage tank, and the outlet of the second heat exchanger is connected with the user end to form an LNG utilization loop; and the liquefied carbon dioxide flowing out from the condensing side of the first heat exchanger is further condensed through LNG as a cold source; the compression unit is connected with a motor driven by an off-peak electric motor for energy storage; and the expansion unit is connected with a user through a power generator to carry out energy release.

Description

technical field [0001] The invention belongs to the technical field of energy storage and energy utilization, and in particular relates to a transcritical carbon dioxide energy storage system and method based on utilization of LNG cold capacity. Background technique [0002] With the depletion of traditional fossil energy and the increasingly prominent environmental problems, the utilization of renewable energy has received more and more attention. The inherent randomness and volatility of renewable energy such as wind energy and solar energy have brought great challenges to the development of renewable energy, so we need to develop energy storage technology to effectively solve these problems. [0003] At present, there are only two large-scale energy storage technologies that can be maturely applied in the world: pumped hydro storage and compressed air energy storage. Steam turbine technology, supplemental combustion of fossil fuels, and caves for suitable storage. In re...

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Problems solved by technology

[0004] In the existing technology, the transcritical carbon dioxide energy storage technology still has the following problems. Its power generation efficiency and energy storage density are not high. In the transcritical carbon dioxide energy storage technology, there is a problem of insufficient liquefaction in the liquid carbon dioxide storage tank. LNG cannot be rationally utilized as a high-quality cold source

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