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marți, 29 mai 2012

The Bilge Pumps Used on Board Ships

It is important to empty ship's bilge wells at regular interval of times to prevent flooding of the engine room. Bilge pumps are used for this purpose.It is important to know the construction and working of these pumps as they are used in emergency situations and also often face technical problems.


We learnt what is bilge water, oily water and use of oily water seperator. Now we will talk a look at these pumps used on board various types of ships and boats and see how does a bilge pump work . A bilge pump found on a ship is generally a reciprocating type or a centrifugal type. The rate of flow provided by a reciprocating type is lesser than that of the centrifugal type. Also, the mechanism and construction of a reciprocating pump is extremely complicated for a pump used for such important purpose.
All the bilge pumps that are generally used on ships are placed below the sea level. Though this helps them to gain extra suction pressure, they often require priming before the start. Reciprocating pumps are self-priming but due to the drawbacks mentioned earlier, their use is getting reduced day by day.
Nowadays centrifugal pumps are generally used as bilge pumps as they provide greater output rate and take lesser time for the pumping process. The only drawback of these pumps is that they don't have a self- priming system. This has not been an obstacle in their use and the problem is compensated by using an external priming system.

Construction of Bilge Pump

A centrifugal pump consists of an impeller. The impeller is fixed at the center with a help of a shaft.It has vanes which are fixed radially and are strategically located.
Around the impeller, a diffuser or volute is fixed. A diffuser is a ring which also has fixed blades that are strategically placed and are used to increase the speed and convert the kinetic energy of the liquid into pressure.
The impeller and diffuser are contained in a casing or the main frame which also supports the motor of the pump.
Thus there are three main parts of a centrifugal pump :
  • Impeller
  • Diffuser
  • Casing
A sealing arrangement is provided around the shaft to prevent leaking of fluid. The sealing arrangement might consist of a gland or a mechanical seal.

Working of Bilge Pump
The liquid enters the pump through the center of the impeller also known as the eye of the impeller. The liquid after entering flows radially out and enters the vanes of the impeller. Due to the rotation of the impeller the velocity of the liquid increases. This high velocity liquid then enters the diffuser or the volute casing where the kinetic energy of the liquid is converted to pressure. This pressurized liquid is pumped out through the pump discharge.Many centrifugal pumps have more than one impeller for increased velocity.

Priming arrangement

As centrifugal pumps are not self priming, they require some additional arrangement to get rid of the air in the suction line. When the liquid that is to be pumped is at a level higher than the pump, then the air in the suction line can be removed by opening an air cock fitted at the pump suction. This will automatically allow the liquid to flow due to gravity.Bilge Pump Priming
If the pump is located below the sea water level and there is a provision made to utilize the pressurized sea water, then priming can be done by opening the sea water cock and the air cock simultaneously.
Alternate priming systems can be an external air pumping unit that provides pressurised air to different pumps simultaneously.

How to prime the bilge pump

So you want to prime a bilge pump before starting. How would you do it? Given below is the step by step procedure of doing it in the right way.
  1. Before starting the pump , open the suction valve and close the discharge valve.
  2. Start the priming unit to the suction line
  3. Start the motor
  4. Keep a watch at the priming process ( It will start when you start the pump)
  5. Once priming is done, open the discharge valve slowly , turn by turn.
  6. Adjust the amount of flow with the help of the suction valve.
  7. Keep the desired output flow by adjusting the discharge valve
  8. While stopping, stop the motor first and then close the discharge and suction valve.

What if the bilge wells overflow?

It is a governmental law that any liquid that has oil particles suspended in it should not be discharged in the open sea. Bilge wells are helpful to store this contaminated water but can sometimes be a threat to the engine room. If the bilge wells overflow it could cause a rise in the level of water up to or above the floor plates. This could lead to accidents, emergency situations or even disturbance in the stability of the ship. For this reason, bilge wells are periodically emptied by pumping out the bilge with the help of bilge pumps.
MARPOL states that bilge water cannot be directly pumped out into the sea. For this reason, bilge water is first passed through an Oily water separator where the level of suspended oil particles in the mixture is significantly brought down. When the PPM (parts per million) of oil particles in the mixture comes down to the permissible limit, it is allowed to be thrown overboard but only when the ship is en route.
Bilge wells are always provided with strainers to prevent solid particles from entering. This is done to prevent choking of the solid particle in oily water separator or bilge pump. Absence of strainers might lead to drop in bilge pump outlet pressure and also reduction in outlet flow of oily water separators.

Fresh Water from Sea Water on Ships

When preparing for a voyage ships take on fresh water which is supplemented throughout the voyage by water making plants. Fresh water is used in motorships as an engine component cooling medium, but steamships use only the distilled water produced by the water-making plant for boiler feed make-up.
When I was a lad at sea many years ago, I sailed on motor and steamships as an Engineering Officer. In those days we had evaporators which used steam from the boilers or the main diesel cooling water as a heating medium to evaporate the seawater. As I gained experience and promotion, one of my duties as 4th Engineer was looking after the vaps, as we called them (among other things).
Nowadays, there are several very efficient types of evaporators still using the same heat sources, and of course we now use osmosis as well.
In the following sections we will examine the current evaporators in use, fresh water and condensate storage tanks, and condensate feed water testing. In this article we shall examine two categories of water evaporators, tube and flash, and have a look at how osmosis equipment operates to produce fresh water from seawater.
We begin with an examination of the types of evaporators used aboard ships.

Types of Fresh Water Evaporators

There are numerous types of evaporators and osmosis equipment used to produce fresh water from seawater on our ships today. Here we shall examine the following types:

Multi-stage Flash Evaporators
This type of evaporator uses a multi-stage process which has two components, the seawater heater and the flash drum, with these being two separate units.
The seawater can be heated using steam or the main engine cooling water, depending on the main propulsion unit.
The heated seawater is pumped into the flash drum, which has numerous sections all at a lower pressure than that of the water heater. Some of the hot seawater flashes of to steam in the first section, before going on through remaining sections, flashing as it moves through them. The steam rises up the flash drum through a demister, and upon contacting the condenser tubesis condensed and pumped via a salinometer to the fresh water or boiler water feed tanks. Should the salt content in the distillate rise to an unacceptable level, the salinometer alarm will be activated and the distillate diverted to bilges.
A sketch of a typical multi-stage evaporator is shown below:

Coil or Tube Seawater Evaporator
This is a modern version of the type used when I was at sea in the 1960s. They used heating coils in those days as opposed to the pipe nest heaters of today. The coils used to become scaled in salt, with the attendant loss in output of distillate.
I was in charge of the vaps and I remember the old Chief coming down to the engine room on my watch and balling me out for the downturn in distillate. We were having problems with the boiler feed water purity (another article will cover the testing and treatment of boiler feed water), so I was blowing down the boiler regularly, which with the associated make-up requirement meant we needed more water pronto.
Anyway I took him up to the vaps and showed him the scaling on the heating coils, reminding him that I was pumping Foss chemicals into the beast to try and break this away.
He pushed me aside and shut off the seawater supply opening up the steam supply which rapidly dried the salt layer on the coils. He then opened the seawater inlet and hey presto – the salt scale cracked and fell of the coils. I used this system several times until I was up for Seconds ticket and examiner wasn’t too pleased to hear of this method, and called the old Chief several unprintable names!
Today we don’t have to resort to these measures as there is an innovative device which uses a material that emits oscillations counteracting the natural seawater oscillations, thereby altering its properties and preventing calcium carbonate scale. (See references section.)
tube and coil evaporator consists of a steel vessel which has a nest of heating pipes near the bottom of the vessel being fed by steam or hot water from the main engine.
There is a tube condenser cooled by seawater installed near the top of the vessel. A vacuum is drawn in the vessel by air ejectors operated by steam or pressurised seawater.
Seawater is fed into the evaporator just covering the heating pipes. Heat is supplied to the pipes and, this combined with the vacuum conditions begins to boil the seawater producing steam. The steam rises up through a demister into the tube condenser where it is evaporated to distilled water. This is collected and pumped via the salinometer to the storage tanks.
A typical tube condenser is shown below.

Osmosis Equipment

Reverse Osmosis Process
Osmosis is a natural process which occurs due to osmotic pressure between two substances divided by a semi-permeable membrane. When the membrane divides two substances of different concentrations of solids, the solvent from the less concentrated solution will flow into the higher concentrated solution, with the membrane blocking the solids.
In an engine room, reverse osmosis takes place in a pressure vessel which contains a tank holding a quantity of seawater and freshwater separated by a semi-permeable membrane. In natural osmosis the freshwater would flow into the seawater, however when pressure is applied to the seawater side the process is reversed. This causes the seawater to flow into the freshwater side, the solids being stopped by the membrane.
A sketch of osmosis in action on ships blackwater is shown below. This can be applied to freshwater osmosis water-makers.

sâmbătă, 26 mai 2012

Absinthe 2.0 has arrived!

Chiar în aceste momente are loc conferința HITB din Amsterdam unde celebrii hackeri care se ocupă de dezvoltarea soluțiilor de jailbreak pentru iDevice-urile noastre sus in anumite demonstratii.
Printre anunturile făcute, Chronic Dev Team a prezentat în premieră noul Absinthe 2.0 cu care putem face jailbreak untethered oricărui iDevice cu iOS 5.1.1
Intreaga prezentare a celor de la Chronic Dev Team o puteti descarca de aici.

Absinthe 2.0 a fost lansat în sfârsit si putem face acum untethered jailbreak oricărui iDevice ce rulează iOS 5.1.1 în doar câtiva pasi simpli.

Pasul 1:
Descărcați Absinthe 2.0:
Pasul 2:
Conectați iDevice-ul la calculator și deschideți programul Absinthe 2.0 descărcat mai devreme. Presupunem că ați făcut backup iDevice-ului vostru, așa cum v-am recomandat mai devreme. Mergeți acum în Settings > General > Reset și alegeți opțiunea Reset all Content and Settings. Potrivit celor de la Chronic Dev Team, dacă faceți acest lucru vă asigurați că instalarea jailbreak-ului se va face rapid și fără probleme.
Pasul 3:
Apăsați pe butonul “Jailbreak” și așteptați câteva minute;
Pasul 4:
După aproximativ 5 minute, jailbreak-ul ar trebui să fie instalat iar voi să aveți un iDevice jailbroken untethered pe iOS 5.1.1. Puteți acum face restore la backup-ul făcut inițial pentru a vă recupera datele.

           How To Use Absinthe 2.0:
1. Make a backup of your device in iTunes by right clicking on your device name under the ‘Devices’ menu and click ‘Back Up’.
2. Once your backup is complete return to your device and go to Settings – General – Reset – Erase all Content and Settings. This will make the jailbreak process much faster.
3. Open Absinthe and be sure you are still connected via USB cable to your computer.
4. Click ‘Jailbreak’ and wait…. just be patient and do not disconnect your device.
5. Once jailbroken return to iTunes and restore your backup from earlier. Right click on your device name under the ‘Devices’ menu in the left panel of iTunes and click ‘Restore from Back Up…’ then select the latest backup you created before. (restoring this backup will return all the content previously on your device ie, apps, photos, etc.)
6. Thanks for using Absinthe, enjoy your jailbroken iDevice!
After copious amounts of work and many sleepless nights Absinthe 2.0 is finally here to jailbreak your device. This release has been a large collaborative effort between Chronic-Dev Team and iPhone Dev Teams (Jailbreak Dream Team)

vineri, 25 mai 2012

Here are the members of the Chronic Dev Team

Today is expected to launch untethered jailbreak solution for IOS 5.1.1 and here those who have worked on its development.

MuscleNerd has post his presentation slides at the Hack in the Box security conference via twitter today. His presentation at Hack in the Box is mostly about the iPhone’s baseband, the various unlock mechanisms developed by the community, and Apple’s technological response to their tampering.
At one point in the presentation, MuscleNerd mentions Apple’s recognition of the unlock community. Starting with the iPhone 4, Apple programmed the baseband to look for message tampering (the method used for iPhone 3GS carrier unlocks). Amusingly MuscleNerd notes that the debug log Apple left in the baseband contains typos referring to “tambering.” In order to combat tambering, the iPhone 4 contains a DEP mechanism dubbed “crossbar.” MuscleNerd and Planetbeing developed a workaround which they implemented in UltraSn0w, the details of which are in the iOS Hacker’s Handbook.
A particularly useful bit of info included in the talk is the chart on Baseband brickability near the end. To ‘brick’ a device is to render it inoperable, or ‘about as useful as brick.’ Although in the case of baseband bricking “only” means that WiFi, data, and bluetooth are inoperable.
Fortunately, newer phones like the iPhone 4 and 4S have basebands which are not brickable with erased or tampered bootloaders, making baseband unlocks on current hardware as safe as jailbreaking. The iPhone 3G and 3GS basebands are only brickable if one of the two bootloader pages are empty, and the original iPhone’s baseband can be bricked if the bootloader image crashed due to bad code. What this shows is that while Apple has made it harder to unlock the baseband, they’ve functionally made it impossible to absolutely break it through tampering.

Absinthe 2.0 will be the name of the new untethered solution, Pod2G preferring to keep the original name of a highly efficient jailbreak tool. Judging from the video images, it seems that Absinthe 2.0 will not require using the VPN function, process is as easy as with version 1.0.

Here's how you can prepare for the new untethered jailbreak solution for iOS 5.1.1

If you did not perform a jailbreak to your device then the situation is very simple because you just have to make a backup with iTunes / iCloud and information from your terminal will be saved. After making a backup you can use the Update button in iTunes, Backup option in iCloud, or OTA Update from your device (Settings>General>Software Update) for updating without deleting data from your terminal. Important to remember is that if you restore, NOT update, will delete all from the device, and the backup does not save all the pictures, messages or any applications installed from other accounts.
If you did make a jailbreak to your device and not interested to save all the applications or tweak’s downloaded through Cydia, then you can follow all the instructions above.
If want to save the applications from Cydia then you can use applications such as xBackup or PKGBackup to save and restore after reinstalling the packages. Pirated applications cannot be saved and reinstalled automatically after restore, so do not expect it. All pirated applications will be deleted during the update or restore process.
After making the iOS 5.1.1 update and have everything reinstalled just wait for Absinthe 2.0 and that's all.
Absinthe 2.0, first will work on all the Apple devices if they have installed iOS 5.1.1, excluding only Apple TV 3rd generation. Absinthe 2.0 will be also compatible with iOS 5.1, however, iPad 2, iPad 3 and iPhone 4S must be updated to iOS 5.1.1.

Here’s the list of compatible devices with Absinthe 2.0

Terminals compatible with Absinthe 2.0 running iOS 5.1:
  • iPhone 3GS;
  • iPhone 4;
  • iPod Touch 3G;
  • iPod Touch 4G;
  • iPad 1.;
Terminals compatible with Absinthe 2.0 running iOS 5.1.1:
  • iPhone 3GS;
  • iPhone 4;
  • iPhone 4S;
  • iPod Touch 3G;
  • iPod Touch 4G;
  • iPad 1;
  • iPad 2 Wi-Fi;
  • iPad 2 3G;
  • iPad 2 2012;
  • iPad 3 Wi-Fi;
  • iPad 3 Wi-Fi + 4G;

joi, 24 mai 2012

Types of azimuth thrusters

An azimuth thruster is a configuration of shippropellers placed in pods that can be rotated in any horizontal direction, making a rudder unnecessary. These give ships better maneuverability than a fixed propeller and rudder system.

There are two major variants, based on the location of the motor:

1.Mechanical transmission, where a motor inside the ship is connected to the pod by gearing. The motor may be diesel or diesel-electric. Depending on the shaft arrangement the mechanical azimuth thruster are divided into L-drive and Z-drive. An L-drive thruster has a vertical input shaft and a horizontal output shaft with one right-angle gear. A Z-drive thruster has an horizontal input shaft, vertical shaft in the rotating column and a horizontal output shaft with two right-angle gears.
2.Electrical transmission, where an electric motor is in the pod itself, connected directly to the propeller without gears. The electricity is produced by an onboard engine, usually diesel or gas turbine. Invented in 1955 by Mr. and Mr. (Pleuger Unterwasserpumpen GmbH), ABB Azipod was the first product using this technology.
Mechanical azimuth thrusters can be fixed installed, retractable and underwater-mountable. They may have fixed pitch propellers (FPP) or controllable pitch propellers (CPP). Fixed installed thrusters are used for tugs, ferries and supply-boats. Retractable thrusters are used as auxiliary propulsion for dynamically positioned (DP) vessels and take-home propulsion for military vessels. Underwater-mountable thrusters are used as dynamic positioning propulsion for very large vessels such as semi-submersible drilling rigs.
Primary advantages are electrical efficiency, better use of ship space, and lower maintenance costs. Ships with azimuth thrusters do not need tugs to dock, though they still require tugs to maneuver in difficult places.
The Azimuth Thruster using the Z-drive transmission was invented in 1950 by Joseph Becker the founder of Schottel in Germany. First applications came in the 1960s under the Schottel brand name and referred to as Rudderpropeller ever since. Joseph Becker was rewarded with the Elmer A. Sperry Award for this invention as a major contribution to the improvement of transportation worldwide.
Later, subsidiaries of ABB, also based in Finland, developed the Azipod thruster, with the motor located in the pod itself. This kind of propulsion was first patented in 1955 by Pleuger of Germany.

External links

miercuri, 23 mai 2012

Top 3 Websites to Track Your Ship

The use of online vessel tracking services has increased exponentially over the last couple of years. Several websites provide ship tracking using the automatic identification system (AIS) to display real time location of the ships. Moreover, the introduction of Google Earth has revolutionized the ship tracking process, allowing access to each and every detail of almost all ships within seconds.
However, it is to note that ship tracking done through these services is only meant for educational purpose. Though most of these service providers promise “real-time” location of the ships, the data displayed is always behind by few minutes or even by several hours.

The most famous and widely used online ship tracking system offers real time data of ships along with advanced search features. The AIS system of the website boasts of a massive data base of ships of every type.   This service not only allows tracking ships but also various ports of the world.
This is another widely used ship tracking service online which allows vessel search through various options such as ship number, tonnage and capacity, ownership, construction etc. It also keeps a track of all ships searched by you and offers premium paid membership for advanced users.
3.  Fleet Mon
Fleet Mon offers almost all features provided by both marine traffic and ship finder. However, Fleet Mon has its own FM explorer which all registered users can use. Fleet Mon is one of the finest ship tracking services which also offers iphone and ipad apps.
Few more worth mentioning:

luni, 21 mai 2012

The largest, most efficient ship in the world

The construction of ten Triple-E vessels, each capable of carrying 18,000 twenty foot containers, will put Maersk Line at the helm of change. The size and capacity of these vessels, at 400 metres long and 59 metres wide, will help reduce energy consumption and lower CO2 emissions.

Facts at a glance:
• A Triple-E class vessel is equipped with a waste heat recovery system, saving up to 10% of main engine power. This equals the average annual electrical consumption of 5,000 European households.
• The Triple-E class travels 184 kilometres using 1 kWh of energy per ton of cargo, whereas a jumbo jet travels half a kilometre using the same amount of energy per ton of cargo.
• The vessel can carry 18,000 twenty-foot-equivalent units (TEU). If all these containers were to be put on a train - it would need to be 110 km long - and if they were put on top of each other they would almost reach beyond the stratosphere (47 km).

Maersk Line's new Triple-E class will be the world's largest ships, a record 400 meters long and 59 meters wide. Triple E stands for Energy efficiency, Environmental performance and Economies of scale. Environmental performance refers to the recyclability and reuse ensured by the cradle-to-cradle passport -- and the extremely low fuel consumption. Energy efficiency is partly derived from the unconventional hull design and the twin propulsion setup. Economies of scale can be attributed to the capacity of more than 18.000 containers reducing the cost of moving a container by 20-30 per cent compared to other vessels in the Asia-Europe trade lane.

vineri, 18 mai 2012

10 Largest Container Shipping Companies in the World

All the same there are a few international shipping companies that lead the race in terms of the scale of operation of their shipping lines. Ten of these leading shipping conglomerates can be listed down as follows:
1. NYKAn acronym for the Japanese shipping company Nippon Yusen Kabushiki Kaisha, the NYK is one of the biggest cargo companies operating internationally.
The company has been in operation since the 1870s, operating a passenger fleet-line before undergoing a transition into a core container shipping company towards the mid-20th century.
2. Evergreen Marine CorporationA shipping conglomerate based in China, the Evergreen Marine Corporation was founded in 1968 by Dr. Yung-Fa Chang, a visionary in his own right.
At present, the company has offices established all over the world and with a operational capacity of more than 160 container ships is regarded to be one the largest cargo shipping companies in the world.
3. CMA-CGM:  France’s leading container shipping company, CMA-CGM came into existence in the year 1978, as a result of series of mergers between previously established shipping corporations. Jacques Saade who is the head of the company was the instrumental force behind its coming into active operation.
At present, the company has a fleet of over 350 ships operating in over 150 routes globally.
4. MaerskA shipping corporation based in Denmark, Maersk Shipping Line is a branch of the AP Moller- Maersk company. Widely well-known for its fleet of container ships, the Maersk Line made its debut in the international container shipping arena in the year 1904.
At present, the company has a fleet of around 500 container ships with a capacity of around 19, 00,000 TEU (Twenty-Foot Equivalent Units).
5. MSCThe Mediterranean Shipping Company, abbreviated to MSC is a Swiss international cargo company which was established in the year 1970.
At present, with a vessel line-up of over 456 container ships, the conglomerate is rated to be one of the most extensive cargo companies in the world.
6. Hapag-LloydThe German based Hapag-Lloyd is one of the most renowned and well-featured companies in terms of international shipping companies. The company was established in the year 1970 as a result of a merger between the Hamburg-American Line and the North German company Lloyd.
Today the shipping corporation has over 130 ships catering to about five million containers on a worldwide scale.
7. APLAn auxiliary company to the Singaporean Orient Shipping Lines, APL is an abbreviation for American President Lines. Founded in the year 1848, the shipping conglomerate just celebrated its 160th anniversary in the year 2008.
One of the most noteworthy achievements of the company is that it was the first company to successfully utilise extra-large (53 feet) containers on its vessels, accounting for shorter cargo transportation.
8. COSCOThe China Ocean Shipping Company or COSCO, as it is popularly known is one of the leading conglomerates in terms of container shipping companies.
At present the company’s operations are spread over 40 countries with a fleet of 150 container ships.
9. HanjinA South Korean conglomerate, Hanjin Shipping Company is one of the largest Asian cargo companies in the world. At present the company has a cargo operational capacity of over 1 billion tonnes on a yearly basis with around a fleet of about 60 ships.
In the year 2003, Hanjin and COSCO formed a strategic alliance. The alliance has benefited both shipping conglomerates and powered them to an unequivocal position as Asia’s leading cargo shipping companies.
10. CSCLCSCL is the abbreviation for the China Shipping Container Lines, a company based in Shanghai. Started in the year 1997, the company soon rose amongst its ranks and today has propelled not just itself but also the country to leading heights in the container shipping industry. The company finds its name in both the Hong Kong and Shanghai Stock Exchanges.
Container shipping is a huge industry and these key players are aware of the minutest operational manoeuvrings necessary to power them to being the world leaders in the commercial enterprise, not just in their home countries but also at an international level.

Top 7 Important Websites For Marine Engineers

These websites must be book-marked by all marine engineers!
Putting our own website right at the top of the list might seem like a marketing tactic, but then we do provide a wide range of articles and latest updates on marine engineering and maritime technology in the simplest language possible. Can you deny that?
Marine Insight offers almost everything, from details on construction and operation of ship’s machinery to onboard safety and latest news. The best part is that Marine Insight is made by maritime professionals, for the maritime professionals.
This website has got everything that a marine engineer needs for preparing for the competency exams. Right from the basics to in-depth case studies, this is definitely a one-stop destination for a resourceful marine engineering knowledge.
One of the main reasons Dieselduck is a must-visit website for marine engineers is that it has got loads of information of a variety of subjects related to maritime industry. Don’t miss the great compilation of videos featured in the “Videos” section of the website.
If everything about marine engines gives you an adrenaline rush, then you would adore this website. Herein, marine engines have been dissected, explained, and offered to the readers in the best possible manner. Don’t forget to check out the “horror stories” section of the website – a must read for all maritime professionals.
Just as the previous website is all about marine diesel engines, steam esteem is all about marine boilers. From information on steamships to various problems related to marine boilers, this website seems to have everything on it. If marine boilers is your area of interest or is a subject that is giving you trouble then this is the one-stop destination for you.
Though the bright hub marine engineering channel offers the best of both deck and engine department, there are some great articles on various marine engineering subjects in here. The only drawback is that it is not updated frequently.
Diesel ship is a great website which has some amazing resources on marine engineering. The salient feature of this website is the highly informative technical videos offered by the “dieselshipacademy”. The website also offers examination preparation material along with other useful information.

Naval Architecture links

miercuri, 16 mai 2012

High Performance Turbine Installation Vessel

The High Performance Turbine Installation Vessel is a new vessel concept from Wärtsilä and Aker Solutions.

Wärtsilä Hamworthy wins third FSRU

Hamworthy Oil & Gas Systems has secured a contract to supply its innovative LNG regasification technology for the third Höegh LNG Floating Storage and Regasification Unit (FSRU) under construction at Hyundai Heavy Industries.
Here’s how it works:
In this system, LNG is heated by propane in a closed loop and the propane is heated by seawater. In situations where the seawater is too cold to supply all the required heating energy, additional heat can be introduced.
The cascade concept is recommended instead of directly heat exchanging with seawater. LNG heat exchanged directly with seawater increases the risk of freezing the seawater in the heat exchanger. Propane as a secondary medium is suggested because of its thermodynamic properties with a low freezing point.
A HAZID analysis has been carried out with DNV to identify risks related to the design and operation of the regasification system. For example, it was concluded that the cascade system is a safer system than the pure seawater based.  LNG enters a cryogenic pump capable of producing the required send-out pressure (e.g. up to 130 bar has been studied). LNG at the required discharge pressure is heated in two stages.
In the first stage LNG is heated from -160°C to -10°C in a compact printed circuit heat exchanger with propane as a heating medium.
In the second stage, LNG can be heated further using seawater as a heating medium in a shell and tube heat
In the LNG/Propane heat exchanger, heat is exchanged against propane circulating in a closed loop. The propane enters the heat exchanger at approx. 0°C at 4.7 bar as gas. In the heat exchanging process propane is condensed, and leaves the exchanger in a liquid state at approximately -5°C.  The propane in the closed loop is then pumped by the circulating pump and heated against seawater in titanium semi welded plate heat exchangers. In these heat exchangers, the propane is evaporated and heated to 0°C before returning as gas to the printed circuit heat exchanger.
Working together with Sinopacific Offshore and Engineering (SOE), Wärtsilä Hamworthy will design and supply the system concept whilst the key equipment and fabrication will be supplied by SOE.
This partnership agreement follows on from the contract to supply a propane-seawater regasification system for the first two 170,000m3 capacity vessels signed in November last year.
FSRU Hoegh lng
Rendering courtesy Hoegh LNG


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