Nanosecond laser texturing for high friction applications

AbstractA nanosecond pulsed Nd:YAG fibre laser with wavelength of 1064nm was used to texture several different steels, including grade 304 stainless steel, grade 316 stainless steel, Cr–Mo–Al ‘nitriding’ steel and low alloy carbon steel, in order to generate surfaces with a high static friction coefficient. Such surfaces have applications, for example, in large engines to reduce the tightening forces required for a joint or to secure precision fittings easily. For the generation of high friction textures, a hexagonal arrangement of laser pulses was used with various pulse overlaps and pulse energies. Friction testing of the samples suggests that the pulse energy should be high (around 0.8mJ) and the laser pulse overlap should be higher than 50% in order to achieve a static friction coefficient of more than 0.5. It was also noted that laser processing increases the surface hardness of samples which appears to correlate with the increase in friction. Energy-Dispersive X-ray spectroscopy (EDX) measurements indicate that this hardness is caused by the formation of hard metal-oxides at the material surface

Biofuel as an alternative shipping fuel : technological, environmental and economic assessment

© Royal Society of Chemistry 2019Fossil derived fuels available for application within the maritime sector have been dominated by heavy fuel oil (HFO), which is conventionally used in low speed (main) engines, and more refined fuels such as marine diesel oil (MDO), which is consumed in fast or medium speed engines. However, increasing fuel costs and regulatory pressure such as the restrictions placed on sulphur content have increased interest in the use of alternative fuels. A number of alternative fuels have been identified and may be viable for use within the maritime sector including straight vegetable oil (SVO) as an alternative to HFO in low speed engines, biodiesel to replace MDO/MGO in low to medium speed engines and bio-liquefied natural gas (bio-LNG) in gas engines using LNG. The potential sources of biomass feedstocks, conversion pathways and technologies are identified. The key parameters limiting their potential application are examined, in particular, availability, technological development, technical integration, and operational consequences. A proposed solution to overcome these limitations is recommended. The effective implementation of these strategies will enable the more widespread use of biofuels in marine applications, significantly reducing emissions from ships and improving global air quality and also protecting the ecological environment.Peer reviewe

Blade Failures on an Axial Compressor by Unexpected Gas Compositions

Case StudiesA fifteen stage axial compressor including a bleed extraction was subject to a major overhaul after nearly 20 years of trouble free operation. Shortly after recommissioning and resumption of the production the compressor faced three major failures within two weeks. A root cause failure analysis was conducted and revealed that the process plant start-up procedures caused gas compositions which deviated strongly from the design conditions. The valve designs as well as the available control parameters were not able to protect the compressor from off-design operating conditions. For future compressor failure prevention, the process start-up procedures were adapted and the existing control parameters/logic was upgraded. The new control logic reacts to the transient process behaviours during start-up by continuous harmonization of the safety valves

Subsea Compression Applications ,

TutorialTutorial 22: The use of Subsea gas compression technology for subsea re-injection and/or gas transport boosting represents a new and exciting application for rotating equipment, which will allow new gas/condensate field production opportunities, enhanced recovery of existing gas/condensate fields and cost effective production from marginal gas fields. This panel session includes short presentations on the benefits of subsea compression, an overview of currently ongoing projects, and recent advances and technologies that are available and/or under development for subsea gas compression. The panel session includes presentations from SIEMENS ENERGY, MAN DIESEL & TURBO, GE OIL & GAS, and DRESSER-RAND and. The respective presentation titles are: 1. Subsea Electrical Distribution – Siemens Energy, 2. HOFIMTM Type Compressors for Subsea Applications – MAN Diesel & Turbo, 3. GE Oil & Gas Experience in Subsea Gas Compression– GE Oil & Gas, and 4. DATUM I Compressor for Subsea Applications: Update on Qualification Efforts- Dresser-Ran

Subsea Compression Applications - Panel Session

TutorialThe use of Subsea gas compression technology for subsea re-injection and/or gas transport boosting represents a new and exciting application for rotating equipment, which will allow new gas/condensate field production opportunities, enhanced recovery of existing gas/condensate fields and cost effective production from marginal gas fields. This panel session includes short presentations on the benefits of subsea compression, an overview of currently ongoing projects, and recent advances and technologies that are available and/or under development for subsea gas compression. The panel session includes presentations from STATOIL, INTECSEA, MAN DIESEL & TURBO, GE OIL & GAS and DRESSER-RAND. The respective presentation titles are: DATUM I Compressor for Subsea Applications: Update on Qualification Efforts- Dresser-Rand; HOFIMTM Type Compressors for Subsea Applications – MAN Diesel & Turbo; Improving Recovery with Subsea Compression – INTECSEA; GE Oil & Gas Experience in Subsea Gas Compression technology Development – GE Oil & Gas; Realization of Subsea Gas Compression – Statoil

Analysis of two stroke marine diesel engine operation including turbocharger cut-out by using a zero-dimensional model

In this article, the operation of a large two-stroke marine diesel engine including various cases with turbocharger cut-out was thoroughly investigated by using a modular zero-dimensional engine model built in MATLAB/Simulink environment. The model was developed by using as a basis an in-house modular mean value engine model, in which the existing cylinder block was replaced by a more detailed one that is capable of representing the scavenging ports-cylinder-exhaust valve processes. Simulation of the engine operation at steady state conditions was performed and the derived engine performance parameters were compared with the respective values obtained by the engine shop trials. The investigation of engine operation under turbocharger cut-out conditions in the region from 10% to 50% load was carried out and the influence of turbocharger cut-out on engine performance including the in-cylinder parameters was comprehensively studied. The recommended schedule for the combination of the turbocharger cut-out and blower activation was discussed for the engine operation under part load conditions. Finally, the influence of engine operating strategies on the annual fuel savings, CO2 emissions reduction and blower operating hours for a Panamax container ship operating at slow steaming conditions is presented and discussed

Subsea Compression Applications - Panel Session

TutorialThe use of Subsea gas compression technology for subsea re-injection and/or gas transport boosting represents a new and exciting application for rotating equipment, which will allow new gas/condensate field production opportunities, enhanced recovery of existing gas/condensate fields and cost effective production from marginal gas fields. This panel session includes short presentations on the benefits of subsea compression, an overview of currently ongoing projects, and recent advances and technologies that are available and/or under development for subsea gas compression. The panel session includes presentations from Shell Global Solutions, Aker Solutions, MAN DIESEL & TURBO, GE OIL & GAS and DRESSER-RAND. The respective presentation titles are: Subsea Processing - Multiphase Boosting and Compression – Shell Global Solutions; Subsea Compression; Present Status and Experience – Aker Solutions; HOFIMTM Type Compressors for Subsea Applications; MAN Diesel & Turbo; GE Oil & Gas Experience in Subsea Gas Compression Technology Development – GE Oil & Gas; DATUM I Compressor for Subsea Applications: Update on Qualification Efforts- Dresser-Rand

Influence of climatic factors on the efficiency of disposal metal-hydride unit for the double-fuel low-speed internal combustion engine of gas tankers

Проанализирована возможность применения сжиженного природного газа в судовой энергетике. Выявлена перспективность утилизации сбросного тепла малооборотных дизельных двигателей применением металлогидридных установок непрерывного действия. Представлена расчетная схема установки и параметры рабочих сред. Приведены результаты математического моделирования процессов в утилизационной металлогидридной установке. Выявлена устойчивость работы утилизационной металлогидридной установки в различных климатических условиях эксплуатации.Contemporary tendencies in the development of ship power engineering have been analyzed. Consideration was given to the specific features of the transportation of liquefied natural gas by gas tankers. The prospects of utilization of the secondary energy resources of marine double-fuel low-speed diesel engines were defined. The metal hydride units of a continuous action were offered for this purpose. The need for the estimation of the influence of climatic factors on the efficiency of disposal metal-hydride unit has been defined. We proposed to carry out the investigation using the methods of mathematical simulation. The model takes into consideration the main physical relations, in particular material and thermal balances, the phase equilibrium, and heat-mass transfer processes. A relative power of disposal metal-hydride unit was taken as the efficiency criterion. The investigation was carried out with the regard to the propulsive unit of gas tanker of a Q-max type with the propulsion engine 9G80ME. The design diagram of the unit and the parameters of working media have been presented. The data of mathematical simulation of processes have been given. The disposal metal- hydride unit showed a reliable operation in different climatic operation conditions. A specific power of the disposal unit ranged from 5.7 to 6.2 %. The mechanical power of disposal unit was equal to 2.5 MW that enables the drive of the fuel gas compressor of propulsion engine and attached electric generator