LNG Bunker Vessel – Proof of Concept Design
HEC was hired by GTT North America to provide a concept design for a 2200m3 LNG bunker barge for US harbor and near-coastal service in order to demonstrate the feasibility of small scale application of their Mark III membrane technology. Working with LNG experts at CH-IV International HEC developed the design for LNG handling systems including small scale reliquefaction. HEC also completed all the structural, mechanical, and regulatory design elements. The design received an Approval In Principle from ABS.
LNG Fuel R&D and Vessel Design Issues
HEC has studied and written extensively on the use of LNG as fuel for marine vessels and been involved in several commerical ship design and construction projects that feature LNG fuel or ‘LNG ready’ design. This includes the drafting of a Technical Advisory for a Class Society on LNG bunkering highlighting the key handling issues for both the bunkering and receiving vessel. A brief overview of some of this work in included in this HEC News Post. We also continue to update our paper on fuel alternatives in the ECA era with the latest fuel price information.
FLNG Cargo Load Management Study
HEC prepared an operability analysis to support the development of a new FLNG installation for an oil major. Such facilities typically load LNG at a constant, near steady rate and discharge to LNGC’s intermittently. Therefore, this study included a statistical analysis of the projected time sequence of LNG quantity on board during an 11 year period in order to analyze the following:
- the static stability and longitudinal strength of the vessel during normal operation, including all standard, and some of the non-standard production/discharge cycles;
- the total time spent with any one LNG tank in the sloshing zone (15% to 25% fill), as well as the longest single duration spent in the sloshing zone and when this might occur;
- the operational management of a typical production/discharge cycle to minimize sloshing exposure;
- the ballasting/de-ballasting rules to be applied during operation for the optimized production/discharge cycle .
LNG Carrier Propulsion Systems Design Study
HEC helped an oil major evaluate propulsion options for their next generation gas carriers. This study involved a careful look at the latest proven technologies including LSD gas injection, tri-fuel SSDG’s, use of BOG or reliquefaction, medium speed diesel electric with geared motors, and exhaust gas recirculation and selective catalytic reduction for NOx reduction. Full CAPEX and OPEX values were derived enabling full life cycle cost/benefit evaluation. HEC developed custom software to allow ongoing research and evaluation of different combinations of equipment and system design.
LNG Ship Design Development
HEC aided a major oil company in the design development for a series of large LNG carrier designs. HEC directed hull form development, including model testing, and worked with shipyards to determine costs of such ships. All currently available LNG containment systems were evaluated for these ships, as were propulsion options.
HEC also performed technical review of the Q-flex and Q-max LNG Carrier designs for one of the partners in the QatarGas3 project . The work included front-end review of the membrane containment system including review of sloshing tests, review and evaluation of the propulsion system options including gas turbine electric and slow speed diesel with reliquefaction, and evaluation of the Owner’s performance specification for the ships.
Feasibility Evaluation of Novel Containment System Designs
HEC has evaluated the feasibility of a number of proprietary LNG containment designs for various clients with application to marine transport of LNG. The work has investigated structural response of the containment systems, concept design of LNG carriers utilizing the systems, and estimates of the cost and fabrication schedules of entire systems.
PLNG Ship Concept Development
Over a period of five years, HEC performed concept design for a ship using a proprietary PLNG containment system. This work included initial ship sizing, hull structure development, full ship FEA, and preparation of shipyard inquiry documents. Further studies extended to several variations on the initial ship design, investigation of different arrangements of the LNG containment system, and included studies of floating LNG storage facilities at both loading and receiving terminals. Detailed studies of gas container supports including finite element and fatigue analysis were also performed.
Gravity Based LNG Terminal
HEC developed a concept design for a gravity-base LNG receiving terminal that could be built in a shipyard using conventional shipbuilding techniques. HEC’s involvement included selecting the LNG containment system, optimizing the configuration, determining nonlinear wave loadings, designing the structure, developing construction techniques, schedules and costs. As part of the project, we developed curves to aid in cost estimation of floating LNG storage and regasification facilities.
Feasibility, Concept, Preliminary Design
- Engineering feasibility studies for several proprietary LNG containment concepts
- Preliminary design of “Prism” membrane-tank LNG carrier to minimize sloshing loads
- Concept design of modifications to Large LNG carrier to offload at submerged turret buoy
HEC’s subsidiary Herbert Software Solutions Inc. has extended their CargoMaxTMshipboard loading program for a series of newbuild membrane tank LNG carriers. The software determines floating stability and hull girder loading to allow ship’s officers to safely operate the vessel within its design limits. We also retain salvage data in house for a number of LNG carriers that will enable quick response in the event of an emergency.