Method and device for preparing gas hydrate by direct phase conversion heat

Abstract

The invention relates to a direct phase change heat transfer type hydration method and a direct phase change heat transfer type hydration apparatus. Firstly, an emulsion of liquid phase change material and water is prepared, wherein a freezing point of the emulsion higher than that of water, the emulsion is cooled to obtain slurry containing solid particles of the phase change material; and then, the prepared slurry is sent to a hydrator and fully contacts with introduced small-molecule gases to finish the hydration. Heat produced during the hydration process is removed in a direct phase change heat transfer way by utilizing the characteristic that a solid absorbs heat when being melt and matching melt heat with hydration heat. The method is suitable for separation and storage of the gases. The apparatus comprises a disperser (7), a container (5), a pressure pump (3), a heat exchanger (2), a hydrator (1) and a regulating valve (6). A temperature variation of the hydrator designed by the invention is maintained within 1 DEG C. A temperature rise in the hydrator is restrained, so that the hydration rate is significantly increased.

Description

technical field [0001] The invention belongs to the field of energy and chemical industry, especially for the storage and separation of small molecular gases such as natural gas, and proposes a direct phase-change thermal hydration method and device. Background technique [0002] Some small molecular gases, such as methane, ethane, carbon dioxide, etc., will form a cage-like solid substance with water in a non-stoichiometric ratio under low temperature and high pressure conditions, called gas hydrates. The research on hydrates originates from the discovery of a large amount of cotton wool-like solids in natural gas transportation pipelines, which can block pipelines in severe cases. At first people's motivation was to try to prevent the formation of this natural gas hydrate, but now more people want to use hydrates to store natural gas, capture carbon dioxide in the air, and separate mixed gases. However, all these applications are limited by the too low hydration rate, whi...

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Problems solved by technology

[0007] First of all, indirect heat exchange is local heat exchange. The temperature near the heat exchanger is low, and the temperature far away from the heat exchanger is high. Due to the inhomogeneity of the internal temperature, the hydration rate will be affected; secondly, the low-temperature heat exchange medium will make The water on the surface of the heat exchanger freezes, which directly affects the heat transfer effect; finally, the uneven temperature and the freezing of the surface of the heat exchanger will become an insurmountable obstacle when the hydrator is scaled up.

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