HYDROCARBONS FROM DEPTHS OF MARINE WATERS

Preamble

The invention refers to a process and its facility unit, composed of interconnected equipment and machinery and its operation procedure, which we call in this text "process facility unit", designated for capture, separation, purification and compression of hydrocarbons located as natural deposits into the depth of marine water media (e.g. depth of seas or oceans, etc) for the purpose of their economic or/and domestic exploitation and use. Above mentioned process unit could be placed and operated on both fixed and mobile bearing marine platforms (e.g. marine vessel).

The importance of this invention is determined by the result of numerous research and specialized studies that have confirmed the presence of methane and other hydrocarbons in the aquatic deep both in water dissolved form and solid state compounds generically called crystal-hydrates.

The water dissolved form of hydrocarbons, mentioned above, located in deep underwater media is characterized by different concentrations of hydrocarbons, as a function of thermodynamic conditions existing there. For example, in the case of methane dissolved in water in isotherm conditions, at 6°C, by changing pressure from 0 to 200 barg, methane concentration in water varies from very small values to 8 kg/m ³ . At the same pressure if the temperature is increasing (e.g. 10°C comparatively with 6°C) the dissolved hydrocarbons content of water is decreasing (see Fig. 1).

The principle of the proposed process here is based on the fact that the content of hydrocarbons in water, as mentioned above, strongly depends on the pressure conditions of the mixture formed by them.

The innovative character of the proposed process consists in the manner of the sequence of actions that start with capturing of fluid mixture having water and hydrocarbons as principal constituents, fluid mixture transport from the depths to the water surface, this upward transport, which is initially stimulated by forced circulation leads to a hydrostatic pressure decreasing that favors the advanced segregation of phases, thus, as a consequence, a gas liquid suspension appears from the initial captured fluid). The appearance of gas-liquid mixture leads to a self-sustained upward movement of this multiphase fluid mixture due to shrinkage of its specific density. Finally, hydrocarbons brought to the water surface from the deep sea are processed in a succession of operations consisting of separation, purification and compression, the hydrocarbons product being sent to the distribution network for exploitation and use.

The advantages of the implementation of this proposed invention are both economic (obtaining hydrocarbons with market characteristics) and environmental, by reducing hydrocarbon emissions from marine water depths towards the environment (Catastrophic release of methane from the decomposition of such deposits may lead to a global climate change, because CH4 is more dangerous gas than C02).

Abbreviations / Definitions

crystal-hydrates: crystals containing aqueous organic compounds and / or aqueous inorganic compounds. Naturally, on Earth gas hydrates can be found on the seabed , in ocean sediments or in deep lake sediments as crystal clusters or in the form of solid particles suspended in ground water. However, natural gas hydrates do not contain only methane but also other hydrocarbon gases, as well as H2S and C02. (crystal-hydrates of gases components are known as clathrate hydrates).

transport tube: a tubular system built at different geometrical shapes, at different scales and dimensions manufactured from various waterproof materials designated to facilitate the transport of fluid mixture from marine water depth towards the water surface. Simultaneous with the fluid transport it is possible to appear other properties transport phenomena (i.e. heat transfer, mass transfer or moment transfer) between the transported fluid and its exterior.

tube's end for fluid capture (capture-end): part belong to the tube on its extremity, immersed in deep marine waters, serving to its feeding with fluid mixture tubes end for fluid discharge (discharge-end): part belong to the tube on its extremity located on the opposite side of the tube's end for fluid capture, serving to evacuate its fluid mixture content; a. Title of the invention

PROCESS AND PROCESS FACILITY UNIT FOR CAPTURE, SEPARATION,

PURIFICATION AND COMPRESSION OF HYDROCARBONS FROM DEPTHS OF MARINE WATER

b. area to apply the proposed invention;

The invention relates to a process and process facility unit for obtaining gaseous hydrocarbons from marine underwater depths, where they can be found dissolved in water and/or in the form of crystalline structures (crystal-hydrates) for their economically exploitation.

c. description of existing situation in the subject of the proposed invention;

Currently no similar procedures, dedicated to this purpose, are known.

d. description of technical problem solved by the proposed invention;

The technical problem solved by the proposed invention is the manner of capture, separation, purification and compression of gaseous hydrocarbons from marine underwater depths where they can be found dissolved in water and/or in the form of crystalline structures (crystal-hydrates).

e. description of technical solution according to the proposed invention, emphasizing the original scientific creation elements or technical features, that solve the technical problem mentioned above;

The process involves capturing the fluid mixture consisting of hydrocarbons and marine water, circulating the above mentioned fluid mixture to the surface by forced circulation combined with self-sustaining circulation, equipped or not with a heating system, separation of hydrocarbons from inert solids, water and non-hydrocarbon gaseous components, and, finally, these separated hydrocarbons are subject to compression and purification. The steps of this procedure are in accordance with the block diagram shown in Figure no. 2.

The process facility unit according to the proposed invention that applies the aforementioned process is characterized by the fact that through a transport tube, equipped with a capture-end and a discharge-end, a fluid mixture, consisting from hydrocarbons and water, are captured from the depth marine locations, and circulated by forced water circulation combined by self-sustaining circulation from the capture-end to the discharge-end located at the marine water surface where are processed in order to hydrocarbons recovery and distributed as a product to different users.

The above mentioned self-sustaining circulation of the fluid mixture is initiated through a forced circulation system which induced an upward movement of the fluid inside the transport tube. The self-sustaining circulation fluid is based on density difference between the ends of the transport tube which occurs due to the tendency of hydrocarbons from the initial fluid mixture to pass into a separate gaseous phase as the fluid mixture reduces its hydrostatic pressure due to its ascendant movement. This synergetic phenomenon can be enhanced by heating the fluid mixture circulating between the ends of the tube.

Once it reaches the marine water surface, the fluid mixture containing as carried components the hydrocarbons and possible some solid particles (due to the pressure reduction it will release the gas phase, the system becoming tri-phases) enters in a phase separator where the solids are removed, the gas phase and respectively the liquid phase follow separate process paths: the liquid phase enters in a heat exchange system to release hydrocarbons that are still dissolved, and afterwards they go into a two-phase separator, the separate water being removed and the resulted gases are in turn combined with the gas phase resulting from the tri-phase separator.

The gaseous hydrocarbons resulted are compressed and purified from acidic gaseous components (C0 ₂ , H ₂ S) in a specific separation unit. Thus, the captured hydrocarbons result from this facility is in a compressed form.

f. example for implementation in practice of the proposed invention;

According with the Figure no. 3 the capture of fluid mixture with high hydrocarbon content, from depth areas of marine water, is done through a transport tube 1 (dimensioned according to suitable calculation algorithms) via its capture-end part and transported through transport tube 1 by forced circulation produced by a dedicated system 2 ^* combined with the fluid mixture self-sustaining circulation.

Thus, by using the system 2 to initiate a forced circulation of the fluid mixture in transport tube 1, a decreasing in hydrostatic pressure of liquid mixture occurs. This hydrostatic pressure decreasing is caused by the upward movement of fluid mixture and its circulation in transport tube 1 becomes self-sustained as a result of the hydrocarbon recess as a gaseous phase that causes the decreasing of fluid mixture density and the increasing of its ascension trend. The liquid phase of entire column of .fluid mixture inside transport tube 1 is quasi-incompressible. This upward movement of the fluid mixture from the capture-end to the discharge-end of transport tube 1 will entail a balancing tendency for the pressures in the system, resulting in the continuous aspiration of fluid mixture** by the capture-end of tube 1 immersed in marine water depths.

Thus, the fluid mixture having a high content of hydrocarbons and also solid particles from depth marine waters set into ascendant motion through transport tube 1 to the discharge-end could be also enhanced by warming of this fluid mixture using natural and /or artificial heating resources.

Once reaching the discharge-end of transport tube 1, the fluid mixture circulating by/through this, becomes a system containing tri-phases (solid-liquid-gas), this fluid system being directed to a separating equipment of the tri-phases 3 which will separate this mixture in three individual phases: a liquid phase, a gaseous phase and a solid phase. The solid phase will be removed and the liquid phase enters in a heat exchange system 4 wherein there occurs the advance released of hydrocarbons still retained in this phase. The effluent from the heat exchange system 4 goes into the two-phase separator 5 where the resulted liquid phase is removed and the gaseous phase combines in the gas meter 6 with the gaseous phase coming from the separator 3.

From the gas meter 6 the gaseous hydrocarbons will be compressed to a specific pressure using a compression system 7, and after this the compressed hydrocarbon enters into a unit for separation and removal of acid components 8, hydrocarbons resulting from the separation being directed to users.

Remarks:

* the flow maintenance system 2 can be located both on the surface and submerged (possibly even at the capture-end of the transport tube)

** the involvement of crystal-hydrates or other solid elements (granules, suspensions, etc.) of relatively small sizes from the proximity is possible and is not excluded (especially if the exploitation depth is close of the seabed)

g. presentation of advantages resulting from the application of the invention;

The advantages of this proposed invention are both economic (i.e. energy sector or chemical processing) and ecological, by reducing its content both in those marine waters and in their environment.