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Turbine Plant for Steam Propulsion Vessels (UST Series)


Main boiler

Ultra steam turbine (UST)

With the latest reheat-regenerative cycle systems and state-of-the art technologies to improve plant efficiency, our Ultra Steam Turbine Plant (UST) delivers the best economic and environmental performance to all customers. UST, our environmental-friendly propulsion system, contributes significantly to customers' good service with reliability and safety.

Main Features

UST Series

  • Much Higher Plant Efficiency
    • - Higher plant efficiency achieving about 15% reduction in fuel oil consumption compared with CST series
  • Highly reliable and safe
    • - Proven design based on established marine and land technologies
  • Environmentally friendly
    • - Low CO2, NOx and SOx emissions
  • Flexible fuel selection
    • - Oil, gas and dual firing
  • Extremely Long Life
    • - Extremely long life due to robust design and appropriate safety margins

Lineup and Specifications

Main Boiler

Series No.MBR-1EMBR-2EMBR-3EMBR-4EMBR-5EMBR-6EMBR-7E
Maximum evaporationkg/h 40,000 45,000 50,000 55,000 60,000 65,000 70,000
Firing Systemkg/h Roof firing for Min Burner, Horizontal firing for RH Burner
Furnace construction- Welded wall
Steam Pressure at S.H.O.MPa 10
Steam temperature at S.H.O.°C 560
Feed water temperature°C 138
Boiler design pressureMPa 12
Boiler efficiency% 88.5 based on the H.H.V. of fuel
Drum distancemm 4,850.0 5,400.0 4,850.0 5,100.0
Furnace depthmm 3,350.0 3,500.0 3,660.0 4,260.0 4,420.0 4,560.0 4,720.0
Furnace widthmm 2,413.0 2,603.5 2,413.0 2,603.5 2,921.0
Number of burners- 2 3

Main Turbine (UST)

Output in MW 13~15 15~18 18~23
Main Frame MR21-II MR24-II MR32-II
HP Turbine Frame HR-20 HR-22
LP Turbine Frame LR-14 LR-16
Reduction Gear Frame Single tandem articulated type
Main Thrust Frame T-8 T-9 T-11
Output in MW 23~26 26~30 30~33 33~37
Main Frame MR36-II MR40-II MR45-II MR50-II
HP Turbine Frame HR-22 HR-26 HR-28
LP Turbine Frame LR-18 LR-20 LR-23
Reduction Gear Frame Single tandem articulated type or
dual tandem articulated type
Dual tandem articulated type
Main Thrust Frame T-13 T-15 T-17 T-19
  • HR-22: High-intermediate pressure turbine with 20- to 22-inch base-diameter
  • LR-18: Low pressure turbine with 18-inch last blade
  • T-13: Main thrust bearing with 13 × 103 cm2 nominal surface areas

Track Record

Track Record for Main Boilers (UST and CST)
Track Record for Main Turbines (UST and CST)

After-Sales Services

In addition to regular maintenance services, we offer a range of value-added services to improve customer satisfaction.

Featured service menu:

For Boilers

Improve combustion: Low load gas mode

We will retrofit existing main boilers with a low-load gas mode, currently equipped as standard on new vessels. This mode allows boilers to operate using gas-only firing when the ship is operating under low loads.

Scheduled maintenance for long-term operation

We will carry out general maintenance of boiler mechanical parts and testing of tubes (superheater tubes, bank tubes, and economizer tubes).

Scheduled maintenance for long-term operation (control and electrical systems)

We will carry out general maintenance of the control system while your ship is docked as a preventive measure to avoid major accidents.

Upgrade of control system to the latest version

We recommend that customers upgrade their control system to the latest version in order to improve the system's response in emergency situations, and to ensure the automatic operation features of the control system function correctly in older boilers.

Training at MHI-MME

We will hold a training workshop at MHI-MME Nagasaki to teach engineers how to troubleshoot boiler-related problems.

Operational data logging for troubleshooting

We install a data logging function on the boiler control panel.

Change to easy-to-remove casing on superheater

We recommend you switch your superheater casing to a type that can be separated into several pieces for easy removal.

For Turbines
To manage operational efficiency, it is vital to maintain high turbine efficiency. We provide various solutions to keep your turbines at optimal condition and reduce your operating costs.

Regular inspections and preventive maintenance

Given the very long service lives of LNG vessels, the turbines on these vessels need to operate for around 20 to 40 years under difficult conditions. It is essential that preventive maintenance of the turbine is carried out to protect against aging deterioration.
We have expert knowledge in preventive maintenance and will help to ensure your vessel has a long, trouble-free service life by replacing and servicing essential turbine components.

Measures to prevent stud bolts from seizing

The nuts and stud bolts used in high temperature areas are made of a high-strength material to stop them overheating. This material though, sometimes causes the bolts to seize.
We recommend replacing existing nuts and bolts with new, improved ones, made of a special material with an aluminium coating to prevent seizing.

Updating the shaft vibration and position monitor

The VM-3 model has been discontinued and maintenance is no longer available. Current monitors however can be replaced by the new VM-5 model without any modification to your system.

Upgrade of turbine remote control system

We strongly recommend renewing the entire remote control system in vessels that have been in service for 15 years or more. The turbine remote control system is an electronic device that includes a computer and a power supply system. According to Japan Electrical Manufacturers' Association (JEMA) standards, the lifespan of the system is 10 years.

Modification of inspection window

We have modified the inspection window to enable easy access during inspections, while simultaneously preventing foreign substances entering while the window is open. The inspection window is securely closed with bolts during operation. For the duration of inspections, all bolts are loosened to open the cover.

Gear tooth surface repair

Micro-pitting has been discovered on the tooth surface of some LP1P1W articulated type reduction gears that have been in operation for 20 years. We recommend repairing the aging deterioration by using state-of-the-art helical gear teeth, which have a projected further 20 years of safe operation.

Replacement of NASH vacuum pumps for condensers

NASH vacuum pumps, which were used for turbines until 1998, are no longer used in marine applications. In order to prevent possible accidents due to the unavailability of replacement parts, we recommend replacing NASH pumps with our latest pump.

Main turbine dock maintenance

We can provide a recommended main turbine dock maintenance parts list that incorporates the docking schedule of each ship for the next 20 years. The list helps stay on top of the maintenance required when your ship is docked.

Change of packing ring to all-in-one type (information only)

We plan to supply a solid-type fin for all new orders.
The HP/LP gland packing ring and diaphragm packing are made-up by embedding fins in the groove of the ring. Since the fins and the ring are made of different materials, their thermal expansion characteristics differ, causing the fins to contract and, in some cases, fall off the groove.

Preparation of spare parts to enable immediate repair of cracks on main valves

In very rare cases, cracks have been found in the valve stellite during scheduled maintenance while ships are docked. These cracks have occurred as a result of low cycle fatigue caused by repeatedly operating and stopping the engine.
We have prepared valve bodies, seats, spindles, bushes and other essential parts to enable us to promptly repair valves found to be cracked during dock maintenance work.

Preparation of backup astern guardian valves

We stock full astern valve assemblies as a backup measure. Recently, cracks have been found in the stellited area of the valve body and valve disc during scheduled maintenance. This is thought to have occurred as a result of low cycle fatigue caused by repeatedly operating and stopping the engine (thermal history).

Inspection of inside of main condenser water chamber

We can dispatch expert technicians to carry out a full inspection of the tube sheet surface, inside the tube, and the rubber lining.
Normally, maintenance work such as cleaning the inside of the water chamber is carried out as part of dock maintenance, but there is concern that a full inspection of inner parts, such as the inside of the cooling tube, the sheet surface, and the inner fitted rubber lining, might not be being carried out to the highest level.

Stocking of turning device parts

We recommend keeping spare parts on hand to perform immediate repairs if required for turning device parts.
Turning devices are installed on turbine ships to prevent thermal damage to the turbine rotors while warming up and cooling down. Recently, incidents of non-compliance, due to operator error, have occurred.

Use of hydraulic torque wrench

Usually, large diameter bolts on the main turbine are tightened by hand using a slug wrench. We recommend using a hydraulic torque wrench when tightening and loosing bolts on the main turbine. Hydraulic torque wrenches are stocked at our warehouses in Dubai and Singapore docks, that can be lent to customers if required.

Upgrading to a higher performance bolt heater

It is better to tighten the special bolts used on high pressure turbine casings with heat, and by cooling afterwards the tension will higher. For safety purposes, we recommend upgrading to an HF induction bolt heater.