RU2807839C1 - Reverse pumping system for cryogenic liquids - Google Patents

Abstract

FIELD: cryogenic liquids.

SUBSTANCE: reverse pumping system for cryogenic liquids is designed to ensure transit pumping, for example, liquefied natural gas from one gas tanker to another used for long-distance transportation by sea. The reverse pumping system for cryogenic liquids is formed on a bundle of insulated cryogenic transfer pipelines made of alternating metal rigid linear sections containing a rigid linear internal product pipe surrounded by a rigid linear casing, and metal deformable sections containing a corrugated deformable internal product pipe surrounded by a corrugated casing, with unidirectional and/or multidirectional flows of cryogenic liquids formed using bandages covering rigid linear casings of adjacent insulated cryogenic transfer pipelines.

EFFECT: reduction of vessel downtime due to the transshipment of cryogenic liquids from ice-class gas tankers to sea-going gas tankers at the same terminal with unidirectional and multidirectional flows of cryogenic liquids.

9 cl, 6 dwg

Description

The reverse pumping system for cryogenic liquids is designed to ensure transit pumping, for example, liquefied natural gas (hereinafter referred to as LNG) from one gas tanker to another and can be used for long-distance transportation by sea.

In the modern structure of energy resource consumption, an important direction of development is the transition of most large companies from “dirty” energy sources to environmentally “clean” sources, which include, in particular, natural gas. Russia is one of the key suppliers of natural gas on the world market, as it has the world's largest proven reserves of natural gas and is in second place in its production. In addition, Russia has already created the necessary conditions for using such a strategic opportunity as the development of large-scale LNG production. An important factor determining the development of LNG production is the unevenness of natural gas reserves across regions of the world, the remoteness of gas fields from consumers by thousands of kilometers, while in most cases it is impossible to organize pipeline supplies of natural gas due to sea and ocean barriers. Thus, the growing demand for LNG creates the necessary incentives to invest in new gas liquefaction and transportation facilities. In turn, the possibility of water transportation of LNG determines its competitive advantage over the supply of natural gas by pipeline over long distances, to regions that are difficult to access and otherwise unprofitable for supplies (N.I. Sasaev. Development of large-scale production of liquefied natural gas as a strategic priority of economic and social development Russia, Management Consulting - 2018, No. 8).

Transportation of LNG by sea is much more profitable than transportation through pipelines in gaseous form, even with small volumes of supplies over long distances - there is no need to lay a pipeline, create infrastructure and large teams to maintain the pipeline. The most economically and environmentally sound way to transport LNG when the LNG consumer is more than 3,000 km away is sea transportation by ships with a capacity of 20,000 to 300,000 tons, and the greater the tanker’s carrying capacity, the cheaper the LNG transportation. However, to transport LNG by sea, the investor needs to lay a gas pipeline to the seashore, build a liquefied natural gas plant on the shore, a port for tankers, and the tankers themselves. As a result, maritime transportation also requires significant capital investment, and its share can reach 30% of the total cost of an LNG project.

Receiving and shipping terminals for LNG, intended for transport vessels (gas tankers) for transporting LNG, should be located on an onshore pier, or a specialized area of the port, or on platforms offshore, depending on the depth of coastal waters and local conditions to allow an LNG transport vessel to approach the terminal. The supply of LNG to the transport vessel can be carried out using a loading arm or hose from an LNG export terminal, which is connected to a liquefaction plant or to an LNG storage tank located on the sea coast at the minimum permissible distance from the sea coastline using one or more cryogenic transport lines (pipelines). These transport lines are typically insulated cryogenic pipelines placed on trestles formed from piles and concrete decking. Planning the laying of such transport lines for cryogenic fluid requires taking into account a number of economic and environmental aspects not only during installation, but also during the further operation of the pipeline (invention patent RU 2627747, IPC F16L 59/14, declared 12/23/2011, published August 11, 2017). It is known that installing support racks for an overwater pipeline or laying a pipeline on the seabed causes restrictions on the use of sea space for other vessels, requires additional costs to strengthen the racks and reduce the corrosive effects of salt water. All these aspects lead to increased economic costs for the installation and maintenance of cryogenic fluid transport lines and negatively impact the ecological state of the environment.

The draft of the gas carrier is of particular importance for sea transportation of LNG; for example, ocean-going gas carriers with a capacity of 250-300 thousand tons have a draft of 20-22 m, which allows them to be accepted only in a limited number of deep-sea ports with a water area depth at the berth or barrel of at least 25 m with subsequent storage of LNG in the terminal tanks, regasification of LNG and its further transportation to consumers via pipelines. In many cases, it is economically feasible to intermediately reload LNG on long routes from ocean-going gas tankers to sea or river gas tankers with low draft for further water transportation, which sharply reduces the vessel's hauling distance; however, systems for cryogenic pumping of LNG are still technically very imperfect .

A system is known for transferring a cryogenic product between two vessels positioned next to each other, from a first floating structure (800) for storing and transporting a cryogenic product to a second fixed or floating structure (900) for storing a cryogenic product by means of a rigid transfer pipeline suitable for transportation. cryogenic product, wherein the transfer pipeline is self-supporting and contains at least three rigid sections (12-17) of the pipeline, each of which is fluidly connected to the next section using connecting means (21-27) suitable for transporting the cryogenic product , wherein each of the two end sections (12, 17) of the pipeline has a free end, made in the form of an end element for connection with the connecting device of the first floating structure (800) and, accordingly, the second floating structure (900), characterized in that it contains ( i) connecting devices configured to be placed respectively on the first structure (800) and on the second structure (900), each connecting device comprising an extension pipe (11, 18) configured to be connected to the receiving device (810, 910 ) of appropriate design and to the end element of the pumping pipeline; and (ii) a mounting support (850, 950) for the free end of each extension pipe, wherein a gap is provided between the extension pipe of the first structure and the mounting support therefor, or between the mounting support and the structure supporting it, to allow the extension pipe to bend in a desired manner after connection. the end element of the pumping pipeline with this extension pipe (invention patent RU 2774086, MPK V63V 27/34, V63V 27/24, declared 12/21/2018, published 06/15/2022). The disadvantages of the invention are:

• in the LNG reception/shipment system there are no lines for discharging boil-off gas into a closed system (clause 95 of the federal norms and regulations in the field of industrial safety “Safety Rules for Liquefied Natural Gas Facilities”);

• to use the system by two vessels placed next to each other, instead of rigid mooring, it is necessary to bring them closer together for a short distance, practically maintained during the entire pumping time, which is unacceptable for mega-tonnage gas tankers;

• pumping LNG from the first floating structure (800) for storing and transporting the cryogenic product to the second stationary structure (900) becomes impossible in high tide areas due to changes in the relative position of the floating and stationary structures, for example, in the Bay of Biscay the water level during the day can vary by 12 m;

• the method allows for pumping LNG in one direction: from the first floating structure (800) for storing and transporting a cryogenic product to a second stationary or floating structure (900) for storing a cryogenic product and does not provide for pumping LNG from the first floating structure for transporting a cryogenic product to a second floating structure for transporting the cryogenic product.

A mooring terminal in the open sea is known, including: a platform fixed to the seabed; a pipeline functionally connected to the platform and in fluid communication with onshore equipment; at least two sets of structures adjacent to the platform, each of which at least two sets of structures are associated with the berth and mooring of ships; and a storage vessel moored and moored to the first of the at least two sets of structures, the storage vessel being configured to transfer a load-bearing load between the carrier vessel operatively coupled to the second of the at least two sets of structures, and storage vessel, and in liquid communication with a pipeline (invention patent WO 2008073152, IPC F17C 9/02, B65/D 88/78, E02B 17/08, declared 07/23/2007, published 06/19/2008). The disadvantages of the invention are:

• gas is pumped from the carrier vessel first to the storage vessel and only then the gas enters the pipeline connected to the platform fixed to the seabed, which leads to the complication of the operation for receiving LNG;

• there is no possibility of continuous reloading of gas through a terminal on an offshore platform to another carrier vessel.

A long-distance offshore LNG export terminal with vapor recovery and recovery capabilities is known, including an onshore or offshore hydrocarbon storage facility (1), an offshore berthing facility (6) for mooring a tanker (11), and at least one subsea pipeline ( 4, 5) extending from the first pump (7, 8) at the storage facility to the offshore transfer structure (6), wherein the transfer structure (6) contains: a vapor separation tank (10) connected to the outlet end (9) of the pipeline , wherein the tank (10) contains a supply line (13, 14) connected to the tanker (11) for supplying liquid hydrocarbon to the tanker, a return line (27) connected to the tanker (11) for supplying vapors from the tanker to the separator (10) , and a steam pumping line (28, 33) connected to an offshore vapor receiving station (24, 32, 35, 37) for supplying steam from the tank (10) to the receiving station, characterized in that the receiving station includes any of the following components or a combination thereof: a power plant (37) and a power cable (38), connected on one side to the power plant (37), and the other side to an onshore and/or offshore facility (1), a compressor (35) for gas compression and a gas pipeline ( 36), connected at one end to the compressor (35), and at the other end to an onshore or offshore structure (1) for supplying compressed gas, and a gas liquefaction device (32) connected by a liquefied gas pipeline (34, 41) to any of the moored tankers (11), storage element (40) for liquefied gas and pipeline (4, 5) or any combination of these (invention patent WO 2006118458, IPC F17C 9/00, filed 04/11/2006, published 11/09/2006 G.). The disadvantages of the invention are:

• the presence of a large communications system (underwater pipelines for pumping liquefied gas, gas pipelines, pipelines from pumps to the storage element, power cables, pipelines for supplying boil-off gases) will complicate its formation, installation, maintenance and repair; the system includes many loading towers that are connected to each other through one or more subsea lines for transporting LNG, which leads to complexity of the system as a whole;

• there is no additional transfer pipeline necessary to maintain cryogenic temperatures in a filled underwater pipeline when pumping cryogenic liquids stops.

Also known is a system for transporting a cryogenic fluid between a floating vessel and a second location, comprising:

a) a first cryogenic riser having a first end and a second end, said first riser adapted to enable change in the vertical position of said first end of said first riser, said second end of said first riser located in a body of water and in fluid communication with said second location at least a portion of said first riser that is isolated; wherein said first riser includes a first riser fluid conduit and a second riser fluid conduit;

b) a first submersible tower connector connected to said first end of said first riser, said first connector adapted to be releasably connected to a first floating vessel located on said body of water so that a cryogenic fluid can be communicated between said first vessel and said first end said first riser, said first connector is moored to the bottom of said body of water such that the vertical position of said first connector can be changed, and said first connector adapted to allow rotation of said first vessel about said first connector on the surface of said body of water, while while said first vessel is connected to said first connector;

c) a cryogenic fluid conduit having a first end and a second end, said first end of said conduit in fluid communication with said second end of said first riser, said second end of said conduit in fluid communication with said second location, and said a pipeline at least partially immersed in said body of water; wherein at least a portion of said pipeline is insulated; wherein a first end of said first standing conduit and a first end of said second standing conduit are connected to said first connector, and a second end of said first standing conduit and a second end of said second standing conduit are in fluid communication with said conduit channel and

d) a connecting pipeline for a fluid, the specified connecting pipeline providing a channel for communication of a fluid between the specified first pipeline for the riser and the specified second pipeline for the riser (invention patent US 7836840, IPC B63B 22/02, filed 07.09.2005, published 05/03/2007). The disadvantages of the invention are:

• unidirectional movement of the fluid medium (LNG), which makes it possible to move LNG through a connecting pipeline buried at the bottom or from one vessel to another when securing them to banks (Fig. 5), or from a gas tanker to a floating or onshore LNG storage facility (Fig. 1), or from a gas tanker to an LNG import terminal (Fig. 6, 7), or from an export terminal to a gas tanker (Fig. 8);

• the depth of the connecting pipeline at the bottom of the water area increases the cost of its installation and complicates repair work in the event of an accident on the pipeline.

There is a well-known cryogenic pipeline proposed by ITP (In Ter Pipe) SA based on an underwater pipeline, which eliminates the need to build expensive overpasses, which has received a DNV certificate and has already been successfully implemented in Peru (Camisea project) for transporting liquefied petroleum gas from an onshore plant to an offshore berth. A feature of the ITPSA technology is a pipeline with a three-layer wall, or “pipe in a pipe in a pipe” - Pipe-in-Pipe-in-Pipe (PiPiP), which allows you to move the berth further from the coast, where dredging is not required, and in addition, no interference with the movement of local maritime transport (Subsea cryogenic pipelines (LNG/LPG) - Pipe-in-pipe …www.itp-interpipe.com/…pipelines/subsea-cryo). The disadvantage of the pipeline is the significant loss of cold when transporting liquefied gas under water due to the high heat transfer coefficient from the pipeline wall to the water, as well as the need for additional installation of the necessary communications under water.

Also known, which is a prototype, is a transfer tunnel block for a cryogenic fluid, containing a facing shell containing inside it:

- a transport line for cryogenic fluid, which, if necessary, contains loop temperature compensators;

- at least one steam return line;

- if necessary, a recirculation line;

- at least one cavity located in the annular space between the outer surfaces of these lines and the inner surface of the facing shell, at least partially filled with cryogenic insulating material;

- at least one communication line;

- at least one discharge line designed to remove steam from at least one cavity, wherein said at least one discharge line contains a plurality of pores in fluid communication with at least one cavity (patent for invention RU 2627747, IPC F16L 59/14, declared 12/23/2011, published 08/11/2017). The disadvantages of the invention are:

• the cryogenic transfer tunnel unit provides only a connection between the unloading and loading terminal and the LNG storage tank on shore and does not solve the problem of transshipment from one vessel to another;

• the facing shell for the transport line of a cryogenic environment, made of concrete or steel, is laid along the seabed without taking into account the topography of the port water area, which can lead to disturbances in the port ecosystem and undesirable negative impacts on the environment, and also complicates access to communications if they need to be repaired.

A common drawback of the considered methods of transporting cryogenic fluids is the one-way operation of pumping terminals: in places of LNG production, the terminals are designed to load LNG gas tankers, and in places of LNG delivery and consumption, gas tankers are unloaded and LNG is regasified. Also, from a technical and organizational point of view, it is difficult to transfer LNG at a marine terminal from one vessel to another, significantly different in capacity, for example, from an ocean-going gas tanker to a sea-going gas carrier or a river-sea gas carrier, associated with the need to optimize the delivery of LNG from the place of its production to the place of its regasification in the presence of a number of technological and marketing restrictions, as well as force majeure circumstances inevitable during sea transportation, and further delivery of natural gas to the consumer through the pipeline network.

The most difficult link to form in the chain of optimized processes under consideration that ensures the delivery of fuel from the producer to the consumer is the reloading of LNG from ocean-going gas tankers to smaller and coastal tankers. This link is difficult to obey programmed dispatch for a number of reasons. Firstly, the technological period for unloading an ocean-going gas tanker with a capacity of 250-300 thousand m ³ of LNG is several days, and the injection of LNG into a coastal gas carrier is 1-2 days. Secondly, changing a loaded coastal gas carrier to an empty one at the terminal requires several days of unproductive time spent on mooring and maneuvering ships, preparing the manifolds of both tankers and the tanks of the loaded gas carrier. Third, due to unfavorable weather conditions, an ocean-going gas tanker may be late to unload LNG, and a coastal gas tanker may be several days late to load LNG. The combination of these factors leads to the fact that at the terminal there is often a significant gap between LNG loading and unloading operations, causing downtime of gas tankers and an unjustified increase in the cost of transported LNG. So, for example, losses from idle time during the day at the roadstead or at the terminal of a gas tanker with a capacity of 145,000 m ³ amount to 30 thousand US dollars, and for an ocean-going gas tanker - up to 67 thousand US dollars. At the same time, the loss of time for the downtime of an ocean-going gas tanker at the terminal is quite large: non-productive operations when a loaded gas tanker is located directly at the terminal (mooring the vessel, preparing stands and manifolds before pumping LNG, drainage, purging and detaching stands during departure) amount to up to 4.5 days (Parshin N.V. Analysis of the operation of the liquefied natural gas transportation system. Marine intelligent technologies. - 2020, No. 1, volume 1, pp. 125-130). Another current type of LNG transshipment from one gas carrier to another is the transfer of LNG transported along the Northern Sea Route by an ice-class gas tanker from the port of Sabetta (Yamal) to a conventional gas tanker sailing in temperate and tropical climatic conditions. The usefulness of such a solution was tested in November 2020 during an experimental tanker-to-tanker LNG transshipment in Russian waters, when the Arc7 ice-class LNG tanker Nikolay Evgenov, capable of breaking through ice up to two meters thick, left the terminal in the port of Sabetta and reloaded LNG. onto the shuttle - a cheaper light tanker of the Arc4 class Yamal Spirit, which had previously returned for LNG from Gibraltar, the LNG transshipment from one vessel to another vessel on a side-to-side basis took place near Kildin Island near Murmansk (https://finance.rambler. ru/economics/45299926/?utm_content=finance_media&utm_mediimi=read_more&utm_source=copylink). Transshipment of LNG cargo on the side-to-side principle at sea is technically very complex and dangerous, in particular, pre-treatment of tanks with nitrogen is impossible, and the transfer of cargo accepted by a gas tanker in Yamal to another gas tanker, according to regulatory requirements, is more conveniently carried out at the Sakhalin terminals with further transportation of LNG to Asian countries or at Portovaya terminals with further transportation of LNG to European countries. At the same time, due to the complexity of transporting LNG along the Northern Sea Route in the autumn-winter-spring period, the reduction of loading and unloading operations at LNG transshipment terminals is of particular importance.

When creating the invention, the task was to develop a system for pumping cryogenic liquids, ensuring the interconnection of unloading and loading objects for transporting cryogenic liquids and the terminal with reducing vessel downtime due to the transfer of cryogenic liquids from ice-class gas tankers to sea gas tankers at one terminal with unidirectional and multidirectional flows of cryogenic liquids.

The problem is solved due to the fact that a system for reverse pumping of cryogenic liquids, connecting at least several above-ground tanks of a tank farm for storing cryogenic liquid with receiving and dispensing devices for cryogenic liquid, but not less than two, and loading and unloading terminals for maintenance, according to at least two gas tankers with receiving and dispensing devices for cryogenic liquid, including pumps installed in cryogenic liquid storage tanks, two or more insulated cryogenic transfer pipelines, one end connected to at least one cryogenic liquid storage tank, and connected at the other end with at least one receiving and dispensing device in the area of the loading and unloading terminal, at least one pipeline for pumping blow-offs, at one end connected with at least one tank for storing cryogenic liquid, and connected at the other end with at least one receiving and distributing device in the loading and unloading terminal area, isolated cryogenic transfer pipelines and a pipeline for pumping blow-offs are laid along the bottom of the port water area, taking into account the bottom topography, while the reverse pumping system of cryogenic liquids is formed on a bunch of isolated cryogenic transfer pipelines made of alternating metal rigid linear sections containing a rigid linear internal product pipe surrounded by a rigid linear casing, and metal deformable sections containing a corrugated deformable internal product pipe surrounded by a corrugated casing, with unidirectional and/or multidirectional flows of cryogenic liquids, formed by means of bandages covering rigid linear casings of adjacent insulated cryogenic transfer pipelines.

Such a design of the reverse pumping system allows, during long-distance sea transportation of LNG, to ensure the formation of a transit terminal for pumping, for example, LNG from one gas tanker to another, for example, from a large gas tanker to smaller coastal gas tankers or from an expensive ice-class gas tanker to a cheaper one of the same displacement. The location of the reverse pumping system on the mainland coast or islands near sea routes for LNG transportation will be determined by a technical and economic calculation from the standpoint of minimizing the costs of transporting LNG from the port of its production to the regasification port. The advantages of the proposed system are:

• use of metal insulated transfer pipelines, which are both durable, flexible and have low heat transfer into water;

• the pipeline follows the underwater terrain, which simplifies its laying along the bottom of the water area;

• flexibility of the system operation, allowing:

a) accept LNG from the donor gas carrier into a land-based tank when the arrival of the recipient gas carrier to the terminal is delayed, which reduces the non-operational downtime of the donor vessel;

b) receive LNG from the donor gas carrier into a land-based tank when the recipient gas carrier performs non-productive operations (maneuvering in the port waters, mooring to the terminal, connecting the stands and cooling the tanks, and after LNG is pumped, disconnecting the stands and purging them, unmooring), which reduces the time non-operational downtime of the donor vessel;

c) ensure recirculation of LNG in the system in the absence of gas tankers at the terminal, which ensures the constant readiness of the system for loading and unloading operations;

d) supply LNG to the recipient gas carrier from a land-based tank when the arrival of the donor gas carrier to the terminal is delayed, which reduces the non-operational downtime of the recipient vessel;

e) supply LNG to the recipient gas carrier from a land-based tank when the donor gas carrier performs non-productive operations (maneuvering in the port waters, mooring to the terminal, connecting stands and cooling tanks, and after LNG is pumped, disconnecting the stands and purging them, unmooring), which reduces the time non-operational downtime of the recipient vessel;

f) supply LNG to the recipient gas carrier simultaneously from the land tank and the donor gas carrier through connecting hoses, which reduces the time of loading LNG onto the recipient vessel;

g) simultaneously receive LNG from the donor gas carrier into the onshore tank and supply LNG to the recipient gas carrier from the onshore tank when the productivity of the pumps of the onshore tank is higher than the productivity of the pumps of the unloading donor gas carrier, which reduces the time of loading LNG onto the recipient vessel;

• the ability to quickly dismantle the system if its operation is unprofitable and transport it on a container ship to a new location.

It is advisable that the metal rigid linear sections of cryogenic transfer pipelines be made with vacuum insulation of the space between the rigid linear internal product pipe and the rigid linear casing, which will sharply reduce the heat exchange between the section and sea water and indirectly the loss of cold from the pumped LNG.

It is also useful that the metal rigid linear sections of cryogenic transfer pipelines be made with thermal insulating material filling the space between the rigid linear internal product pipe and the rigid linear casing, which will significantly reduce the heat exchange between the section and sea water and indirectly the loss of cold from the pumped LNG and at the same time increase the strength of the section .

When forming the system route, it is possible to use metal deformable sections of cryogenic transfer pipelines, which can be made by filling the space between the deformable corrugated internal product pipe and the deformable corrugated casing with heat-insulating material, which, along with repeating the profile of the bottom of the water area when laying sections of cryogenic transfer pipelines, will reduce cold losses from transported LNG.

It is recommended to additionally attach sinkers to the bands, since due to the low density of LNG, situations are possible when the force of gravity, pressing the entire pipeline system for transporting cryogenic liquids along with auxiliary pipelines and cables to the bottom of the water area, cannot compensate for the kinetic force of waves and currents in the water area, As a result, the pipeline system may be displaced from its design position. For the same reason, it is possible to secure the entire pipeline system for transporting cryogenic liquids, together with auxiliary pipelines and cables, on movable and/or fixed supports buried in the soil of the seabed.

An option is possible when the entire pipeline system for transporting cryogenic liquids, together with auxiliary pipelines and cables, is placed in an additional casing mounted on movable and/or fixed supports buried in the seabed, which will protect the entire system from accidental damage, for example, when an anchor is released ships in the roadstead. It is also possible in cases of intensive traffic of vessels with a deep draft with a small gap relative to the bottom of a shallow bay, at the bottom of which there is a pipeline system for transporting cryogenic liquids along with auxiliary pipelines and cables, that the entire pipeline system will be placed in an additional casing and placed in a trench or in sarcophagus in the soil of the seabed.

The feasibility of the proposed system for reverse pumping of cryogenic liquids is illustrated as an example in Figures 1-6, using the following notation:

1 - system of insulated cryogenic transfer pipelines;

2 - tank for storing cryogenic liquid;

3 - transfer pump;

4 - loading and unloading terminal;

5 - filling device;

6 - sea gas tanker;

7 - ice-class gas tanker;

8 - sinkers;

9 - pipeline for blow-offs;

10 - transfer cryogenic product pipelines;

11 - cables and communications;

12 - bandage;

13 - concrete tunnel;

14 - flexible section of the transfer pipeline;

15 - rigid section of the transfer pipeline;

16 - inclined part of the pipeline;

17 - vertical part of the pipeline;

18 - caisson;

19 - U-shaped compensator;

20 - sarcophagus.

Figure 1 shows a basic general system for reverse pumping of cryogenic liquids. LNG from the cryogenic liquid storage tank 2 of the tank farm through a transfer pump 3 installed in the cryogenic liquid storage tanks 2 is supplied to a system of insulated cryogenic transfer pipelines 1 laid along the bottom of the port water area taking into account the bottom topography, including two or more insulated cryogenic transfer pipelines pipelines and two or more pipelines for pumping blow-offs, one end connected to a tank for storing cryogenic liquid 2, and connected at the other end to a receiving and distributing device in the area of a loading and unloading terminal 4, equipped with a loading device 5. At the same time, at the loading and unloading terminal 4 LNG is transshipped from ice class 7 gas tankers to sea-going gas tankers 6.

Figure 2 shows an isolated system of isolated cryogenic transfer pipelines 1, including pipelines for blow-offs 9, transfer cryogenic product pipelines 10, cables and communications 11 for information transmission, connecting sensors and actuators of the tank farm and loading and unloading terminals, surrounded by a bandage 12, which is fixed in a stationary state by means of weights 8.

In cases where there is a risk of damage to the pipeline system for transporting cryogenic liquids, for example, by the anchors of small vessels located in the water area together with LNG reloading vessels, the bandage 12 can be replaced with a casing. The casing containing the entire pipeline system for transporting cryogenic liquids along with auxiliary pipelines and cables is fixed on movable and/or fixed supports buried in the seabed soil or placed in a trench in the seabed soil.

Figure 3 shows a design option for an isolated system of insulated cryogenic transfer pipelines 1, including transfer cryogenic product pipelines 10, cables and communications 11, placed in a bandage (or casing) 12 located in a concrete tunnel 13. The bundle of insulated transfer cryogenic product pipelines 10 includes an inclined part of the pipeline 16 and the vertical part of the pipeline 17. A similar option can be used when leveling the profile of the bottom of the water area, for example, when laying a channel for guiding gas tankers with deep draft to a terminal in a shallow bay.

Transfer cryogenic product pipelines 10 are made of alternating metal linear rigid sections of the transfer pipeline 15 containing a rigid linear internal product pipe surrounded by a rigid linear casing, and metal flexible sections of the transfer pipeline 14 containing a corrugated deformable internal product pipe surrounded by a corrugated casing. The metal rigid sections of the transfer pipelines 15 are made with vacuum insulation of the space or filled with heat-insulating material between the rigid linear internal product pipe and the rigid linear casing. The metal flexible sections of the transfer pipelines 14 are made to fill the space between the deformable corrugated internal product pipe and the deformable corrugated casing with heat-insulating material.

Figure 4 shows the structural elements of transfer cryogenic product pipelines 10, including U-shaped compensators 19, installed on linear sections of cryogenic transfer pipelines with a large length from the onshore tank for storing cryogenic liquid to terminals located away from the coastline on pile overpasses in places where there are sufficient depths for the passage of gas tankers and caissons 18.

Figure 5 shows an option for protecting the cryogenic transfer pipeline system using a sarcophagus 20, which houses an additional casing with the entire pipeline system for transporting cryogenic liquids along with auxiliary pipelines and cables. The sarcophagus is installed on the seabed soil by inserting the sarcophagus spikes into the grooves of the foundation foundations buried in the ground (A), which ensures reliable adhesion of the sarcophagus to the seabed soil and provides additional protection for the reverse pumping system of cryogenic liquids from the adverse effects of both natural and man-made factors.

Figure 6 shows diagrams of a number of options for the operation of a cryogenic liquid reverse pumping system using the example of LNG pumping from an ice class 7 donor gas tanker to a recipient sea gas tanker 6 under various operational situations:

a) acceptance of LNG from the donor gas carrier into a land-based tank when the arrival of the recipient gas carrier to the terminal is delayed, which reduces the non-operational downtime of the donor vessel;

b) acceptance of LNG from the donor gas carrier into a land-based tank when the recipient gas carrier performs non-productive operations (maneuvering in the port waters, mooring to the terminal, connecting stands and cooling tanks, and after LNG is pumped, disconnecting the stands and purging them, unmooring), which reduces the time non-operational downtime of the donor vessel;

c) ensuring recirculation of LNG in the system in the absence of gas tankers at the terminal through two transfer cryogenic product pipelines 10, interconnected by a hose, which ensures constant readiness of the system for loading and unloading operations;

d) supply of LNG to the recipient gas carrier from a land-based tank when the arrival of the donor gas carrier to the terminal is delayed, which reduces the non-operational downtime of the recipient vessel;

e) supplying LNG to the recipient gas carrier from a land-based tank when the donor gas carrier is performing non-productive operations (maneuvering in the port waters, mooring to the terminal, connecting stands and cooling tanks, and after LNG is pumped, disconnecting the stands and purging them, unmooring), which reduces the time non-operational downtime of the recipient vessel;

f) supplying LNG to the recipient gas carrier simultaneously from the land tank and the donor gas carrier through connecting hoses, which reduces the time of loading LNG onto the recipient vessel;

g) simultaneously receive LNG from the donor gas carrier into the onshore tank and supply LNG to the recipient gas carrier from the onshore tank when the productivity of the pumps of the onshore tank is higher than the productivity of the pumps of the unloading donor gas carrier, which reduces the time of loading LNG onto the recipient vessel.

Options for the operation of the reverse pumping system for cryogenic liquids a, b, d, e, f and g reduce the non-operational downtime of cargo tankers or loading time, which reduces the cost of chartering tankers.

Example 1. LNG supply from the port of Sabetta (Yamal) to the port of Dabhol (India) is carried out by icebreaking class Arc7 gas tankers with a carrying capacity of 170,000 m ³ within 30-35 days due to the fact that when the vessel passes the Northern Sea Route from the port of Sabetta to Cape Dezhnev, depending on ice conditions, takes 11-16 days and then to the port of destination - 19 days. The full turnaround of the vessel due to LNG loading and unloading operations in two ports for 3 days is 76 days and over a year of operation, taking into account stops for technical inspection, the tanker will be able to perform 5 trips. With a capacity of the LNG plant in Yamal of 16.5 million tons (27.5 million m ³ ), transportation of LNG for export will require 32 Arc7 icebreaking class gas tankers with a carrying capacity of 170,000 m ³ and costing $320 million. When a system of reverse pumping of cryogenic liquids is formed in the area of the port of Petropavlovsk-Kamchatsky using the port infrastructure with cargo transshipment from gas tankers of the icebreaking class Arc7 to cheaper (cost 180 thousand dollars) gas tankers of the Arc4 class of the same carrying capacity, the full turns of the vessels will be for Arc7 38 days (10 flights per year) and for Arc4 44 days (8 flights per year). Then, if there is a reverse pumping system, to ensure the operation of the LNG plant in Yamal, 16 Arc7 type gas carriers and 20 Arc4 type gas carriers will be required. During reverse pumping, the number of gas tankers will increase slightly (36 versus 32) due to the additional loss of time for LNG reloading of 1.5 days per trip; the associated additional freight costs ($30,000 per additional day of demurrage) would be approximately $14.5 million/year:

((16 Arc7)-(10 flights)+(20 Arc4)-(8 flights))⋅(1.5 hours)⋅(30000)=14400000 US dollars/year.

At the same time, the cost of the tanker fleet due to the introduction of reverse pumping and changes in the structure of the tanker fleet will decrease from

(32 Arc7)⋅(320 million $)=10240 million $

before

(16 Arc7)⋅(320 million $)+(20 Arc4)⋅(180 million $)=8720 million $,

that is, the costs of creating a tanker fleet in Yamal can be reduced by 1.5 billion dollars or 105 billion rubles at an exchange rate of 1 $ = 70 rubles. when using the LNG reverse pumping system in the port of Petropavlovsk-Kamchatsky.

Example 2. In example 1, additional costs for chartering a gas tanker with a carrying capacity of 1,700,000 m ³ were considered in the amount of $45,000 with a standard time cost of 1.5 days for calling at the port of Petropavlovsk-Kamchatsky and unloading or loading LNG based on data from N.V. Parshin. (Analysis of the operation of the liquefied natural gas transportation system. Marine intelligent technologies. 2020, No. 1, volume 1, pp. 125-130). The components of time spent entering a port are determined by the regulations:

- departure of the tanker from the direct route to the port of Petropavlovsk-Kamchatsky - 8.6 hours;

- maneuvering in the port waters - 1 hour;

- mooring - 1 hour;

- connecting stands and cooling tanks - 1.5 hours;

- start of shipment - build-up (7000 m ³ at a speed of 7000 m ³ / h) - 1 hour;

- shipment of 91.75% of the vessel’s carrying capacity at a speed of 14,000 m ³ /h - 11.3 hours;

- completion of shipment - reduction (7000 m ³ at a speed of 7000 m ³ / h) - 1 hour;

- disconnecting the stands (drainage and blowing of the stands) - 1.5 hours;

- departure - 0.5 hours;

- access to the open sea - 8.6 hours.

The total turnaround time for a vessel at the port during an additional call is 36 hours or 1.5 days for individual processing of a single tanker.

When using a reverse pumping system, joint synchronous processing of two tankers is possible at the same time, for example, the donor tanker discharges LNG into the ground tank using on-board pumps, and the recipient tanker receives LNG from the ground tank using the tank's submersible pumps, in this case the total time LNG tanker trips for a single shipment of LNG from the manufacturer to the customer will be reduced by 18.8 hours, which will reduce freight costs for two vessels by:

(30000⋅18.8)/24=23500 dollars

or 1645000 rub. at an exchange rate of 1$=70 rubles.

Thus, using the example of LNG transportation, a solution to the problem of developing a system for pumping cryogenic liquids is shown, ensuring the interconnection of unloading and loading objects for transporting cryogenic liquids and the terminal with a reduction in vessel downtime due to the transshipment of cryogenic liquids from ice-class gas tankers to sea-going gas tankers on one terminal with unidirectional and multidirectional flows of cryogenic liquids.

Claims (9)

1 A reverse pumping system for cryogenic liquids connecting at least several ground tanks of a tank farm for storing cryogenic liquids with receiving and dispensing devices for cryogenic liquids, but not less than two, and loading and unloading terminals for servicing at least two gas tankers with receiving and dispensing devices for cryogenic liquid, including pumps installed in cryogenic liquid storage tanks, two or more insulated cryogenic transfer pipelines, one end connected to at least one cryogenic liquid storage tank, and connected at the other end to, by at least one receiving and dispensing device in the area of the loading and unloading terminal, at least one pipeline for pumping blow-offs, one end connected to at least one cryogenic liquid storage tank, and connected at the other end to at least , one receiving and distributing device in the loading and unloading terminal area, insulated cryogenic transfer pipelines and a pipeline for pumping blow-offs are laid along the bottom of the port water area, taking into account the bottom topography, characterized in that the reverse pumping system of cryogenic liquids is formed on a bundle of insulated cryogenic transfer pipelines made of alternating metal rigid linear sections containing a rigid linear internal product pipe surrounded by a rigid linear casing, and metal deformable sections containing a corrugated deformable internal product pipe surrounded by a corrugated casing, with unidirectional and/or multidirectional flows of cryogenic liquids formed using bandages, covering rigid linear casings of adjacent insulated cryogenic transfer pipelines. 2 The system according to claim 1, characterized in that the metal rigid linear sections of cryogenic transfer pipelines are made with vacuum insulation of the space between the rigid linear internal product pipe and the rigid linear casing. 3 The system according to claim 1, characterized in that the metal rigid linear sections of cryogenic transfer pipelines are made by filling the space between the rigid linear internal product pipe and the rigid linear casing with thermal insulating material. 4 The system according to claim 1, characterized in that the metal deformable sections of cryogenic transfer pipelines are made by filling the space between the deformable corrugated internal product pipe and the deformable corrugated casing with thermal insulating material. 5 The system according to claim 1, characterized in that sinkers are additionally attached to the bands. 6 The system according to claim 1, characterized in that the entire pipeline system for transporting cryogenic liquids, together with auxiliary pipelines and cables, is fixed on movable and/or fixed supports buried in the soil of the seabed. 7 The system according to claim 1, characterized in that the entire pipeline system for transporting cryogenic liquids, together with auxiliary pipelines and cables, is placed in an additional casing mounted on movable and/or fixed supports buried in the seabed soil. 8 The system according to claim 1, characterized in that the entire pipeline system for transporting cryogenic liquids, together with auxiliary pipelines and cables, is placed in an additional casing and placed in a trench in the seabed soil. 9 The system according to claim 1, characterized in that the entire pipeline system for transporting cryogenic liquids, together with auxiliary pipelines and cables, is placed in an additional casing and placed in a sarcophagus on the seabed.