WO2020060417A1

WO2020060417A1 - A device for redundancy in a gas supply between a plurality of sources and a plurality of consumers

Info

Publication number: WO2020060417A1
Application number: PCT/NO2019/050189
Authority: WO
Inventors: Svein Roald NIKOLAISEN
Original assignee: Nsk Ship Design As
Priority date: 2018-09-19
Filing date: 2019-09-18
Publication date: 2020-03-26
Also published as: NO20181218A1

Abstract

A system (1) for supplying at least two consumers (145) of gas with gas from at least two sources (135) of gas, which is such that the sources (135) supply a main pipe (3) with gas, and the consumers (145) are supplied with gas from the main pipe (3), and the main pipe (3) comprises at least two driving sections (31) and an intermediate shut-off section (33), and at least one sectioning valve (74) is positioned between a driving section (31) and the shut-off section (33).

Description

A DEVICE FOR REDUNDANCY IN A GAS SUPPLY BETWEEN A PLURALITY OF SOURCES AND A PLURALITY OF CONSUMERS

Introduction

The present invention relates to a system for providing redundancy and flexibility in a supply system for gas from a plurality of sources to a plurality of consumers. In par- ticular, the invention relates to a gas-supply system on a ship where the source corn- prises a tank of liquid gas and an evaporation plant, and where a consumer comprises a gas-valve unit that supplies a gas-driven motor. More specifically, the invention re- lates to running all gas-carrying pipes from a plurality of evaporation plants to a main pipe, arranging the main pipe in two or more driving sections, the driving sections being interconnected two by two via an intermediate shut-off section, and supplying all consumers from this main pipe. The invention also relates to housing the main pipe in a gastight device so that the device constitutes a secondary barrier against gas leakage. Background

In recent years, more and more ships have started using gas as fuel for motors for propulsion and general power production. Usually, the gas fuel is stored in liquid form in tanks. Whenever needed, the fuel is carried to the evaporation plant where heat is added. In the evaporation plant, the liquid changes into gaseous form. From the evap- oration plant, the gas is carried to a gas-valve unit (GVU). The GVU is a control unit which, among other things, controls the pressure of the gas before the gas continues to a gas-driven motor.

Each motor is provided with an evaporation plant of its own and a GVU of its own. The pipe connection between the evaporation plant and GVU and the pipe connection be- tween the GVU and the motor is a pipe-in-pipe (double-walled pipe) connection. The outer pipe is ventilated or filled with nitrogen gas. Thereby extra protection is achieved in case of leakage, so that gas leakages into free air are avoided. A system like that for supplying the motors with gaseous fuel does not give any flexi- bility, and there is no surplus of gas, redundancy, in the system, either. If a fault aris- es in, for example, the supply A, the pipe system A must be shut down and the motor A is turned off. Thereby, the energy from one motor is lost because of a fault, where the fault in itself may be a minor fault. In other words, there is no redundancy in the supply line of each motor.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features that are specified in the description below and in the claims that follow.

General description of the invention

Definitions

In what follows, a tank provided with an evaporation plant is referred to as a source. A GVU is referred to, in what follows, as a consumer. A system according to the invention will create redundancy and flexibility in a gas- supply system. When a fault occurs in the source A, the source A is shut down, but the consumer A gets gas fuel from one or more of the remaining sources. A device corn- prising a main pipe is positioned between the evaporation plant and the GVU. The de- vice will be a device that gathers all the gas-carrying pipes from the source so that each individual source may supply each individual consumer with gas. The device may be prefabricated and produced in series. The device is arranged to be installed on a suitable base on a ship. This has the advantage of enabling testing of the device be- fore installation.

The invention is defined by the independent claim. The dependent claims define ad- vantageous embodiments of the invention.

The invention relates, more specifically, to a system for supplying at least two con- sumers of gas with gas from at least two sources of gas, so that the sources supply a main pipe with gas, and the consumers are supplied with gas from the main pipe. The source of gas may be an evaporation plant adding heat to liquid gas so that the gas takes the gaseous form. A consumer of gas may be a gas-driven motor, or the con- sumer may be a gas-valve unit supplying a gas-driven motor with gas as described before. The consumer may also be a gas boiler, a gas turbine, etc. The main pipe is divided into consecutive sections with valves and comprises at least two driving sections and an intermediate shut-off section. A driving section is connect- ed to at least one gas-carrying pipe from the source and at least one gas-carrying pipe to the consumer. At least one sectioning valve is positioned between a driving section and the shut-off section. The main pipe may comprise three driving sections and two intermediate shut-off sections, so that there is one intermediate shut-off section be- tween two driving sections. The main pipe may comprise more than three driving sec- tions and more than two intermediate shut-off sections. Two cooperating sectioning valves may each be positioned on a respective side of a bulkhead. One source may supply one driving section with gas, and one driving section may supply at least one consumer with gas.

The main pipe may be housed in a gastight device. The device may comprise at least two supply and distribution chambers and one intermediate flushing and segregation chamber, and one supply and distribution chamber may house one driving section, and the flushing and segregation chamber may house the shut-off section. A gastight bulkhead may separate the supply and distribution chamber from the flushing and segregation chamber.

The main pipe may comprise a nitrogen plant for flushing out gas. The gas may op- tionally be flushed out through the GVU or the evaporation plant or be sucked out through an extraction system. Each supply and distribution chamber may be provided with a ventilation system. The flushing and segregation chamber may be provided with a ventilation system. The ventilation system may be a natural, passive system. The ventilation system may be an active, mechanical system.

The system may be positioned on a vessel. In what follows, an example of a preferred embodiment is described, which is visual- ized in the accompanying drawings, in which :

Figure 1 shows a principle drawing of a gas supply between a gas tank with an evaporation plant and a gas-valve unit that supplies a motor with gas according to the prior art; and Figure 2 shows a diagram of a gas supply between a plurality of gas sources and a plurality of consumers according to the invention. In the figures, the reference numeral 100 indicates a system for gas distribution from a gas tank 110 to a gas-driven motor 120. Such a system 100 is prior art. The gas tank 110 may be filled with liquid gas 111. The liquid gas 111 is brought into the gas- eous form by heating in an evaporation plant 130. From the evaporation plant 130, the gas is carried to a gas-valve unit (GVU) 140 through a first double-walled pipe connection 150. The GVU 140 is a control unit which, among other things, controls the pressure of the gas before the gas continues through a second double-walled pipe connection 160 to a gas-driven motor 120. The evaporation plant 130 constitutes a source 135 of gas, and the GVU 140 constitutes a consumer 145 of gas. In figure 1, two gas tanks 110 are shown, each supplying two sources 135 with liquid gas 111. Each source 135 supplies one consumer 145 with gas, and one consumer 145 supplies one gas-driven motor 120 with gas. This is shown in figure 1 by the source 135 A sup- plying the consumer 145 A with gas, the source 135 B supplying the consumer 145 B with gas, etc.

Figure 2 shows a system 1 for gas distribution from a source 135 to a consumer 145 according to the invention.

A device 2 comprises at least three chambers 21, 23. The device 2 comprises at least two supply and distribution chambers 21. The device 2 may also comprise more than two supply and distribution chambers 21. The device 2 comprises at least one flushing and segregation chamber 23. The flushing and segregation chamber 23 is positioned between two supply and distribution chambers 21. If desirable, the device 2 may be extended into comprising three or more supply and distribution chambers 21 with one flushing and segregation chamber 23 between each supply and distribution chamber 21.

The device 2 is a rigid unit. The device 2 may be formed out of metal, such as steel. The chambers 21, 23 of the device 2 are gastight so that the device 2 constitutes a secondary barrier against gas leakage, where gas-carrying pipes 41, 42 constitute a primary barrier against gas leakage. The device 2 may be prefabricated and placed on a base (not shown). The chambers 21, 23 are built as rigid structures, and the cham- bers 21, 13 constitute a secondary barrier against gas leakage. The device 2 compris- es a gastight outer wall 25 and a gastight bulkhead 27 between the supply and distri- bution chamber 21 and the flushing and segregation chamber 23. Each chamber 21, 23 may be provided with one or more manhole covers (not shown) or some other suitable access to enable inspection of the chamber 21, 23 and maintenance of the chamber 21, 23. The device 2 comprises a main pipe 3. The main pipe 3 extends through the chambers 21 and 23 and is run in a gastight manner through the bulkheads 27. The main pipe 3 is sectioned in such a way that a driving section 31 is positioned inside a supply and distribution chamber 21 and a shut-off section 33 is positioned inside a flushing and segregation chamber 23.

The gas-carrying double-walled pipe connection 150 from the source 135 to the con- sumer 145 is divided into a first double-walled pipe connection 151 between the source 135 and the device 2 and into a second double-walled pipe connection 152 be- tween the device 2 and the consumer 145. A gas-carrying first pipe 41 of the double- walled pipe connection 151 is connected in a gastight manner to the driving section 31 of the main pipe 3 inside the supply and distribution chamber 21. A first outer pipe 48 of the double-walled pipe connection 151 is terminated in a gastight manner against the outer wall 25, and an annular space between the gas-carrying pipe 41 and the outer pipe 48 is terminated against the outer wall 25. In an alternative embodiment (not shown), the annular space may be extended through the outer wall 25 so that the supply and distribution chamber 21 is connected to the annular space between the gas-carrying pipe 41 and the outer pipe 48. Figure 2 shows that two sources 135 are connected to the driving section 31. More than two sources 135 may be connected to the driving section 31 (not shown). The number of sources 135 is two or more. A gas-carrying second pipe 42 of the double-walled pipe connection 152 is connected in a gastight manner to the driving section 31 of the main pipe 3 inside the supply and distribution chamber 21. An outer pipe 49 of the double-walled pipe connection 152 is terminated in a gastight manner against the outer wall 25, and an annular space be- tween the gas-carrying pipe 42 and the outer pipe 49 is terminated against the outer wall 25. In an alternative embodiment (not shown), the annular space may be ex- tended through the outer wall 25 so that the supply and distribution chamber 21 is connected to the annular space. Figure 2 shows that two consumers 145 are connect- ed to the driving section 31. More than two consumers 135 may be connected to the driving section 31 (not shown). The number of consumers 145 may be different from the number of sources 135. There may be one consumer 145.

The main pipe 3 may be closed and opened inside the flushing and segregation cham- ber 23. When the main pipe 3 is closed in the flushing and segregation chamber 23, the driving sections 31 of the main pipe 3 in their respective supply and distribution chambers 21 are isolated from each other. The device 2 may comprise a ventilation system 5. The ventilation system 5 is shown as a mechanical ventilation system 5 and may comprise a supply unit 51 supplying air via a supply line 53 to the device 2 through a ventilation inlet 54, a ventilation outlet 55, and an outlet line 57 connecting the ventilation outlet 55 to an exhaust plant 59. Each chamber 21, 23 may be supplied with ventilation air from a respective supply unit 51 as shown in figure 2. Each chamber 21, 23 may be provided with a ventilation outlet 55. In an alternative embodiment, the ventilation system 5 may consist of a passive ventilation system 5 without the supply unit 51 and the supply line 53.

The device 2 may comprise a nitrogen plant 6. The nitrogen plant 6 may comprise a nitrogen supply 61 which, via a nitrogen supply line 63, supplies nitrogen to the shut- off section 33. A nitrogen outlet line 67 connects the shut-off section 33 to an extrac- tion system 69, also known as an "Extraction system for double-walled pipes". The person skilled in the art will know that inert gasses other than nitrogen may be used in such a nitrogen plant 6. The supply of gas to the driving section 31 of the main pipe 3 through the first gas- carrying pipe 41 is controlled by one or more valves 71. The supply of gas from the driving section of the main pipe 3 to the second gas-carrying pipe 42 is controlled by one or more valves 72. Valves 73 control the outlet of air from the supply and distri- bution chamber 21 and air from the flushing and segregation chamber 23 to the outlet lines 57. Valves 77 control the admission of ventilation air from the supply unit 51.

The main pipe 3 is provided with at least one sectioning valve 74 between the driving section 31 and the shut-off section 33. A sectioning valve 74 is shown positioned in the flushing and segregation chamber 23 and a cooperating sectioning valve 74 is shown positioned in the supply and distribution chamber 21 on the respective sides of the bulkhead 27. The shut-off section 33 is defined between two pairs of sectioning valves 74.

The nitrogen plant 6 is provided with an inlet valve 75 which controls the supply of nitrogen to the shut-off section 33 from the nitrogen supply line 63. The nitrogen plant 6 is further provided with a venting valve 76 controlling venting from the main pipe 3 to the extraction system 69. When the venting valve 76 is open, the inlet valve 75 is closed.

The valves 71-76 may be remote-controlled, and the valves 71-76 may be pressure- air-operated, electrically operated or hydraulically operated as is known in the art. The energy supply to the valves 71-76 is not shown. In ordinary operation of the device 2, the main pipe 3 is sectioned. The sectioning valves 74 are closed. Should a fault arise in a source 135 supplying gas to one of the driving sections 31 of the main pipe 3, the valve 71 of the first gas-carrying pipe 41 of this source 135 is closed. The sectioning valves 74 are opened and all the consumers 145 are undisturbedly supplied with gas.

Should a fault arise in one of the supply and distribution chambers 21, the sources 135 supplying gas to this supply and distribution chamber 21 are closed and the sec- tioning valves 74 are kept closed to isolate this driving section 31 of the main pipe 3 from the rest of the main pipe 3. The consumers 145 that are supplied with gas from this driving section 31 are also shut down, whereas consumers 145 supplied with gas from one or more of the still operative driving sections 31 are still operative.

Replacement and maintenance may be carried out on sources 135, the driving section 31 and consumers 145 that are connected to one supply and distribution chamber 21, while the rest of the consumers 145 are operative. The nitrogen plant 6 may be used for flushing the entire main pipe 3 or one or more driving sections 31. This is controlled with the valves 71, 72, 74, 75 and 76. The valve 76 is normally kept closed. Opening the valves 75 and 71, and closing the valves 72 in addition to 76, flushes the first gas-carrying pipe 41 leading to the source 135. Open- ing the valves 75 and 72, and closing the valves 71 in addition to 76, flushes the sec- ond gas-carrying pipe 42 leading to the consumer 145.

It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative em- bodiments without departing from the scope of the attached claims. In the claims, reference numbers in brackets are not to be regarded as restrictive. The use of the verb "to comprise" and its different forms does not exclude the pres- ence of elements or steps that are not mentioned in the claims. The indefinite article "a" or "an" before an element does not exclude the presence of several such elements.

The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage.

Claims

C l a i m s

1. A system (1) for supplying at least two consumers (145) of gas with gas from at least two sources (135) of gas, c h a r a c t e r i z e d i n that the sources (135) supply a main pipe (3) with gas, and the consumers (145) are supplied with gas from the main pipe (3), and the main pipe (3) comprises at least two driving sections (31) and an intermediate shut-off section (33), and at least one sectioning valve (74) is positioned between a driving section (31) and the shut-off section (33).

2. The system (1) according to claim 1, wherein at least one source (135) sup- plies one driving section (31) with gas, and one driving section (31) supplies at least one consumer (145) with gas.

3. The system (1) according to any one of the preceding claims, wherein the main pipe (3) is housed in a gastight device (2).

4. The system (1) according to claim 3, wherein the device (2) comprises at least two supply and distribution chambers (21) and one intermediate flush- ing and segregation chamber (23), and one supply and distribution chamber (21) houses one driving section (31), and the flushing and segregation chamber (23) houses the shut-off section (33).

5. The system (1) according to claim 4, wherein a gastight bulkhead (27) sepa- rates the supply and distribution chamber (21) from the flushing and segre- gation chamber (23).

6. The system (1) according to any one of the preceding claims, wherein the main pipe (3) comprises a nitrogen plant (6) for flushing gas.

7. The system (1) according to any one of the preceding claims, wherein each supply and distribution chamber (21) is provided with a ventilation system (5).

8. The system (1) according to any one of the preceding claims, wherein the flushing and segregation chamber (23) is provided with a ventilation system (5).

9. The system (1) according to any one of the preceding claims, wherein the system (1) is positioned on a vessel.