RU2335426C1 - Vessel for condensed gas transportation - Google Patents

Abstract

FIELD: transportation.

SUBSTANCE: vessel for condensed gas transportation is assembled of sections consisting of subsections including reservoir sections filled with inert gas produced by vessel plant, installed in reservoirs of containers for condensed gas made in the form of cylinders reinforced by external coating and integrated in cartridges with locating them in thermally insulated detachable tanks equipped with pipeline to transfer gas from loading-unloading buoys. Cylinders and detachable tanks are made of low-magnetic steel. Cartridges are made of foam-gas concrete over which electrochemical protection anodes are installed. Outer surface of detachable tanks is equipped with fluoroplastic pad inside which springs are located in radial, axial and tangential directions. Springs are linked with each other. Pipeline for gas transfer is provided with high-pressure swivel. Pipeline elements located in detachable tank are positioned in foam-gas concrete mass.

EFFECT: gas transportation to regions with hard climate conditions is provided.

5 dwg

Description

The invention relates to the gas industry, namely to watercraft mainly for transporting liquefied gas.

Known craft for transporting oil and gas, which are shuttle and linear tankers, including ice reinforcements [1, 2], made with a double bottom, double sides and tanks of insulated ballast [3]. For transportation of gas liquefied by pressure increase, add-on cargo tanks made of carbon steel with a design pressure of not more than 2 MPa are used, which are placed both on deck and in holds on special foundations. On gas carriers with a combined method of gas liquefaction, auxiliary tanks are thermally insulated and are installed only in holds. The material of tanks for gas with a liquefaction temperature of 223 K is heat-treated fine-grained unalloyed steel, the material of tanks for gas with a liquefaction temperature of 218 K and lower is aluminum alloys [4], steel alloyed with nickel and chromium, special alloys are Invar, containing 36% nickel, and gas liquefied at atmospheric pressure, is transported in thermally insulated insulated and membrane or semi-membrane tanks. In this case, the membrane is a thin metal shell resting on the inner skin of the body through the supporting insulation.

Free tanks have various shapes, including spherical, cylindrical and prismatic. To transport gas with a temperature below 236 K, tanks are equipped with a secondary continuous barrier, which serves as a temporary capacity for leaked cargo. When flammable gases are transported, the hold space around the tank shell is filled with inert gas stored in tanks or generated by a ship installation. To ensure safety, gas carriers are equipped with instruments for measuring the temperature of the cargo and the hull, pressure, tank filling level, gas analyzers and fire alarm sensors. In this case, the monitoring sensors must be non-conductive tools (Technical conditions for the sea transportation of gas condensate in bulk. RD 31.11.31.42-83, p.367).

In the known device [2], the tanks are made of concrete and equipped with a pipeline and additional side tanks, which in their upper part are fully or partially filled with solid permanent ballast.

In known designs of vessels for transporting liquefied gas, cargo tanks are made of carbon steel or aluminum alloys. When welding such structures, it is necessary to meet the requirements of impact strength standards both for the material itself and for welds. Due to the fact that for the construction of tankers it is necessary to manufacture a significant number of panels, assemble them in sections of medium and large sizes and, finally, assemble a tanker body from large sections in a dock, it is very time-consuming to ensure high impact strength around the entire perimeter of welds. To prevent a decrease in impact strength in the heat affected zone, the amount of heat input and the temperature between the passages are limited, which significantly increases the duration of welding.

In addition, the use of materials with different chemical compositions for welding tanks and hulls, taking into account inductions of chemical and electrical origin during the operation of boats for their intended purpose, is a prerequisite for the occurrence of electrochemical corrosion, which can lead to negative consequences.

In the known device [5], intended for the transportation of liquefied gas, the identified shortcomings are eliminated by welding subsections and sections forming tanks and ultimately the body of the craft made of cold-resistant steel containing a small amount of alloying elements and having a relatively low carbon equivalent, which does not require prior heating during welding. However, in order to maintain a high low-temperature impact strength, it is necessary to strictly maintain the amount of heat input, since otherwise the microstructure and viscosity may decrease for one of two reasons. If the heat input is too low, bainite or martensite can form as a result of relatively quick cooling of the seam. With a large heat input, boundary ferrite grains can appear due to needle ferrite with a more pronounced harmful effect on viscosity.

In addition, this device uses two types of materials with a relatively similar structural composition, but differing in chemical composition, which may be a prerequisite for the occurrence of electrochemical corrosion during the operation of the craft for its intended purpose.

Also known are the designs of gas carriers [6], in which cylinders are used that are welded from two longitudinal joints of steel X-80 with an inner diameter of 1 m. The cylinders are combined into cassettes of 8 pieces and installed in a fire-resistant casing made of lightweight fire-resistant vibration-proof composite materials, or reel-type cylinders are used, which are a 15.8 km long pipe wound on a coil with an external pipe diameter of 168.3 mm. The number of rows of pipes in the coil is 24 rows. Coils are combined into a multi-tiered tank. Thus, in the well-known design of Coselle reel cylinders, the tank consists of 5 tiers and weighs 200 tons. Thus, on a CNG / PNG tanker of the Cran and Stening company, 108 reel cylinders are grouped into 18 reel tanks. However, the practical implementation of coil tanks requires solving a wide range of technological problems related to the analysis of coil stresses and deformations, including the load due to its own weight, analysis of the distribution of pressure and gas temperature in the coil, taking into account the loads associated with thermal expansion, and taking into account the stresses during winding ( ovality, unwinding, changes in wall thickness, lateral pressure, intersections, residual stresses), analysis and consideration of metallurgical defects, analysis of combinations of stress th and boundary conditions. In addition, it is also necessary to take into account the peculiarities of the hydraulic modes of operation of coil tanks, including taking into account restrictions on the gas composition (pipe corrosion, the influence of associated gases), analysis of dynamic loading and unloading processes.

A common disadvantage of the known devices is that the construction of a specialized vessel is associated with significant material costs and the payback of such a vessel is directly related to the presence of long-term gas supplies between the gas supplier and consumer, as well as the rhythm of supply due to navigation conditions. And if in the southern latitudes the operation of specialized gas carriers is economically justified, then in the northern latitudes and especially in the Far North, the profitability of such vessels will be low.

The objective of the proposed technical solution is to reduce material costs during sea transportation of liquefied natural gas mainly from the Far North.

The problem is solved due to the fact that the vessel for transporting liquefied gas, assembled from sections consisting of subsections, including sections of tanks filled with inert gas produced by the ship installation, installed in tanks of containers for liquefied gas, made in the form of cylinders, reinforced with an external coating and combined in cassettes with their placement in thermally insulated removable tanks, equipped with a pipeline for pumping gas from loading and unloading buoys, in which cylinders and removable tanks are filled non-magnetic steel nets, cassettes are made of foam concrete, on top of which anodes of electrochemical protection are installed, the outer surface of the removable tanks is equipped with a fluoroplastic lining, inside of which are springs located in the radial, axial and tangential directions and joined together, the pipeline for pumping gas is equipped with a high swivel pressure, pipeline elements located in a removable tank, are placed in the mass of foam concrete.

The implementation of cylinders and removable tanks made of low-magnetic steel provides an increase in the toughness of structural elements of a craft for transporting liquefied gas by 3-4 times. Compared with analogues and prototype, such characteristics as tensile strength from 255 to 650 MPa, elongation from 24 to 30% or more, impact strength from 24 to 100 J / cm are significantly increased.

In addition, the implementation of cylinders and removable tanks from a material homogeneous in chemical composition significantly reduces the likelihood of electrochemical corrosion.

Placing a fluoroplastic lining on the outer surface of the base of removable tanks, inside which springs are located located in the radial, axial and tangential directions and articulated to each other, allows to increase the degree of abrasion during repeated loading and unloading operations, as well as the resistance of ship vibration and eliminate the need for foundation for the installation of removable tanks.

The implementation of cartridges from aerated concrete with the placement of electrodes of electrochemical protection on its surface increases the degree of internal insulation and reduces the likelihood of the formation of electrochemical pairs, the presence of which can lead to accelerated corrosion damage. In addition, the implementation of cassettes of aerated concrete with the placement of pipeline elements in it, located in the tank, reduces the effects of marine vibration.

The supply of a gas pumping pipeline with a high-pressure swivel ensures reliable docking with a raiser, loading and unloading terminals and buoys, and also provides loading and unloading of ships not only at specially equipped terminals, but also at BTL type free buoy terminals (buoys located on the water surface ), STL and SAL (flooded buoys) and allows for gas transportation in areas with severe climatic conditions that are characteristic of remote offshore fields gas supply (region of the Far North), eliminate the effect of restrictions on unloading in ports near major residential and industrial centers, as well as reduce the risk for residential centers by unloading compressed gas at offshore terminals or in an external roadstead using ship lifting equipment.

The use of removable tanks allows you to use this vessel after unloading to transport other goods, when following the vessel in the opposite direction, towards the field.

New distinctive features of the proposed technical solution, consisting in the implementation of cylinders and removable tanks of the vessel for transporting liquefied gases from low-magnetic steel, cartridges made of foam concrete with placement of electrochemical protection anodes on their surface, supplying the outer surface of the base of removable tanks with a fluoroplastic overlay, inside of which springs are located in the radial, axial and tangential directions, articulated with each other, the supply of swivel tanks of the removable tanks is high of pressure for docking with the loading and unloading buoy and placing duct elements, located in the tank, in gazopenobetona weight, of the prior art have been identified that allows to conclude that the proposed technical solutions patentability criteria "inventive step".

The essence of the proposed technical solution is illustrated by drawings.

Figure 1. Scheme of a vessel for transporting liquefied gas. The diagram shows: the hull 1 of the vessel, section 2, subsection 3 and the elements 4 forming a protective barrier, removable tanks 5.

Figure 2. Scheme of a removable tank. The removable tank 5 includes a housing 6, a fluoroplastic overlay 7, an airtight cover 8, shelves 9, guide ribs 10.

Figure 3. The fluoroplastic overlay 7 includes a fluoroplastic surface 11, within which springs 12 are located.

Figure 4. Cassettes with balloons. In cartridges 13 are located cylinders 14, the pipeline 15 with the swivel high pressure 16.

Figure 5. High pressure swivel diagram 16.

Tanks 5 and cylinders 14 are made of low-magnetic steel, for example, type NS-5 T, which is a rolled sheet with a thickness of 1 to 40 mm, having the following characteristics:

- magnetic permeability of more than 1.01 m;

- yield strength of more than 400 MPa;

- tensile strength of more than 650 MPa;

- elongation of more than 30%;

- relative narrowing of more than 50%;

- impact strength of more than 100 J / cm.

The manufacture of tanks 5 and cylinders 14 from low-magnetic steel provides the required microstructure of the weld metal and, accordingly, high impact strength. In this case, almost any welding electrodes with low moisture absorption and any welding processes (manual, mechanized, semi-automatic) can be used.

The hull 1, sections 2, subsections 3 and the elements 4 forming a protective barrier are a reservoir (hold), in which tanks 5 are installed by means of portal or ship lifting devices.

Tanks 5 are an insulated container with a sealed lid, equipped with guide ribs and shelves for the installation of cartridges with cylinders. At the same time, the dimensions of the shelves are reduced from the bottom of the vessel to the deck, which makes it possible to install cartridges with cylinders in tiers with the formation of a multi-tier tank and to exclude the pressure of the upper cartridges on the lower ones, as well as to ensure a more complete filling of the hold with inert gas.

The outer surface of the base of the tanks 5 is equipped with a fluoroplastic overlay 7, which includes a fluoroplastic surface 11, inside which springs 12 are located, located in the radial, axial and tangential directions and articulated between each other.

The cylinders 14 are made of low magnetic steel and are a pipe with two plugs. The cylinders 14 on the outside are reinforced with a layered coating, which is formed by special winding on the surface of the steel fiberglass cylinder, followed by impregnation with its rubber mastic UN1A1, UN1A2. The inner diameter of the cylinder is 1.0 m, the height is 10.0 m. The cylinders 14 are installed in cartridges 13 of 12 pieces.

Cartridges 13 are made of foam concrete, on the surface of which anodes of electrochemical protection are placed. Cartridges 8 are a design made in the form of cells in which the cylinders 14 are installed.

The pipeline 15 is used for pumping gas during loading and unloading. The high-pressure swivel 16 provides docking with the raiser external loading and unloading devices. The elements of the pipeline 15, located inside the tank 5, are placed inside the mass of aerated concrete, as are the cylinders 14, which reduces the effect of ship vibration on the elements of the pipeline.

Pipeline 15 is also articulated with a ship compressor station.

The standard sizes of tanks, cartridges and cylinders can be selected in accordance with the dimensions of the holds of the vessel in operation, taking into account the requirements of the standard for the construction of offshore pipelines OS-F 101.

The practical implementation of the claimed technical solution of industrial complexity does not present, which allows us to conclude that the claimed technical solution meets the condition of patentability "industrial applicability".

Information sources.

1. Offshore transport systems for the export of oil from Arctic deposits / Yu. Simonov, V. Minin, Yu. Polyakov, A. Pinsky // Fuel and Energy Complex Technologies, No. 1, 2004, p.2.

2. RF patent No. 2203197.

3. Rules for the construction of ships. L., USSR Register, 1989, p. 32-33.

4. A vessel with aluminum spherical tanks for transporting natural liquefied natural gas / Navigator (International Maritime Journal), special issue, 1997, p.1, p.14.

5. Welding of tankers for transporting liquefied gas by the ESAB / Svetsaren method, Volume 58, No. 1, 2003, pp. 1-8.

6. CNG Final Report. Rev 9.2. doc. Email: sar@INTARI.COM.

Claims (1)

A vessel for transporting liquefied gas, assembled from sections consisting of subsections, including sections of tanks filled with inert gas produced by a ship installation, installed in tanks of containers for liquefied gas, made in the form of cylinders, reinforced with an external coating and combined into cassettes with their placement in thermally insulated removable tanks equipped with a pipeline for pumping gas from loading and unloading buoys, characterized in that the cylinders and removable tanks are made of low-magnetic steel, cash desk They are made of foam concrete, on top of which electrochemical protection anodes are installed, the outer surface of the removable tanks is equipped with a fluoroplastic lining, inside of which are springs located in the radial, axial and tangential directions and articulated to each other, the pipeline for pumping gas is equipped with a high-pressure swivel, pipeline elements, located in a removable tank, placed in the mass of aerated concrete.

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