+ All Categories
Home > Documents > Product Loading - Marine Loading Arm

Product Loading - Marine Loading Arm

Date post: 10-Feb-2016
Category:
Upload: invilink87
View: 1,482 times
Download: 89 times
Share this document with a friend
Description:
marine loading arm
Popular Tags:
10
Marine Loading Arm (MLA) Marine Loading Arm is an articulated pipe system for then transfers of liquids or gases. This may maneuvered manually or hydraulically. A marine loading arm comprises several components namely: base riser Inboard arm Outboard arm The articulation is assured by swivel arrangements. These arrangements (or styles) allow for complete movement in all planes.
Transcript
Page 1: Product Loading - Marine Loading Arm

Marine Loading Arm (MLA) Marine Loading Arm is an articulated pipe system for then transfers of liquids or gases. This may maneuvered manually or hydraulically. A marine loading arm comprises several components namely:

• base riser• Inboard arm• Outboard arm

The articulation is assured by swivel arrangements. These arrangements (or styles) allow for complete movement in all planes.

Page 2: Product Loading - Marine Loading Arm

MLA Design – Model1. Fully Balance Marine Arm (FBMA)

FBMA is the simplest type fully balance loading arm having main counter weight and sub counter weight. Both Manual and Hydraulic powered operation are available and Manual type can be operated with very less workers. As the construction is very simple, maintenance and overhaul are also very easy. Tanker Size: 100 to 5,000 DWT (deadweight tonnage).

2. Rotary Counterweighted Marine Arm (RCMA) / Double Counterweighted Marine Arm DCMA

RCMA and DCMA mainly used for loading/unloading with middle to large tankers. Both RCMA and DCMA fully balanced in all position but RCMA have rotatable counter weight can get balance of both outboard and inboard arm and it affect to reduce the weight. Tanker Size: 3,000 to 500,000 DWT

Page 3: Product Loading - Marine Loading Arm

MLA Design – Material SelectionMaterial of construction for MLA is much dependent on the fluid service and process parameters. The example as follow:

Page 4: Product Loading - Marine Loading Arm

Overall safety of MLA operations1. Emergency Release System (ERS)

ERS disconnect loading arms from the tanker immediately during loading of product in the event of emergency, such as fire disaster, and strong current that causes sudden movement of tanker away from berthing line. ERS unit is placed at outer end of loading arm (style 80 swivel joint). Components in ERS include:

ERS Valve - In the event of emergency, two valves will be closed simultaneously without spillage of product inside the loading arm and tanker pipe before disconnection. Valves type ball valve or butterfly valve.

Emergency Release Coupler - Located between two valves. Disconnect the loading arm from the tanker instantly after valve closed.

Hydraulic/Electric control system - Control emergency valve and emergency coupler. Interlock system to provide full protection against accidental operation and technical malfunctions. Furthermore, the system employs evacuation of loading arm after disconnected from the tanker automatically.

Page 5: Product Loading - Marine Loading Arm

2. Quick Connect/Disconnect Coupler (QCDC)

QCDC provide easy positioning and quick connection to ship's manifold by hydraulic power (manual also available). Features include:

Safety - Connection will be done by remote control, minimize risk for injuring at the connection flange even under swelling condition and the operator can stay away from the hazardous cargo such as cryogenic liquid or high temperature liquid.

Manpower and Time Saving - compare to ordinary bolting flange connection. For cryogenic service, QCDC can break away even under built up ice condition after loading operation. Using remote control (radio or wired), connection operation can be done by single operator. The flanging guide system eases the alignment.

Reliable Seal - The clamp will grasp and evenly tighten the manifold flange that will ensure reliable seal.

3. Position Monitoring System (PMS)

PMS provides realtime information of the position of loading arms during loading operation. Angle sensors attached on the Loading arm can detect the position of the top loading arm, position of tanker, its drifting speed, and allowable moving range of loading arms.

Page 6: Product Loading - Marine Loading Arm

MLA Emergency Shutdown (ESD) protectionThe shutdown of the loading arms occurs when one or more of the following events take place:

1. Manual activation from the Panel in the Loading Dock control room, or DCS in the main control room in case of product leakage or fire.

2. Automatic activation due to loading arm over-travel (due to ship movement).

For a proper ESD system activation, the following actions will be initiated:

1. ERS/PERC valves close in 5 seconds.2. Loading arm transfer valves close in 20 seconds.3. Main transfer valves near the dock entrance close in 30 seconds.4. Pump transfer valves at the LNG storage tanks close in 30 seconds.5. Vent valves on each loading arms open in 5 seconds.6. Loading pumps trip.

Improve the reliability of the existing surge protection system, pressure switches installed on the loading line, which function to trip the loading pumps and open the vent valves at specified set pressure when the main surge protection fails.

Page 7: Product Loading - Marine Loading Arm

Maintenance Interval of Loading Arm ComponentsRecommended maintenance intervals for MLA components are as follows. However, it depends on condition of use such as operation frequency or site condition.

Page 8: Product Loading - Marine Loading Arm

Reference sources:

1. OEM specification

2. Nasrul Syahruddin, LNG Loading Lines Surge Analysis for ESD System Application, 2010.


Recommended