The expansion of Carbon Capture, Utilization, and Storage (CCUS) highlights the growing need for carbon dioxide (CO2) pipeline transportation. While pure CO2 is non-corrosive, impurities such as H2O and NO2 create a corrosive environment that risks pipeline integrity. This study investigates how H2O and NO2 concentrations, along with temperature, influence corrosion under CO2 pipeline conditions. The investigation was performed in an autoclave setup emulating a linear velocity of 0.96 m/s at 100 bar and temperatures of 5 °C and 25 °C, testing X52 and GR70, and a more corrosion-resistant 9Cr alloy. The results indicated that the presence of NO2 elevated the corrosion rate compared to scenarios without. Low H2O concentration led to a corrosion rate of up to five times higher at 5 °C, compared to at 25 °C, in the presence of NO2. Low to moderate corrosion was observed for the carbon steels without NO2 and with 70 ppmv H2O at both temperatures. Reducing the H2O concentration below 70 ppmv and removing NO2, while SO2 and O2 are present, will only result in low to moderate corrosion in the carbon steel CO2 pipeline. The corrosion rate for X52 and GR70 was 0.065 mm/y and 0.016 mm/y higher or 5 and 3 times greater, respectively, at 5 °C compared to 25 °C. The study concludes that H2O should be maintained below 70 ppmv and NO2 should be eliminated to prevent severe corrosion. Emphasizing the importance of CO2 specification compliance and the need for further research into CO2 compositions that align with the specifications.
Nowadays, sea traveling is increasing due to its practicality and low-cost. Ferry boats play a significant role in the marine tourism industry to transfer passengers and tourists. Nevertheless, traditional ferry ships consume massive amounts of fossil fuels to generate the required energy for their motors and demanded loads. Also, by consuming fossil fuels, ferries spatter the atmosphere with CO2 emissions and detrimental particles. In order to address these issues, ferry-building industries try to utilize renewable energy sources (RESs) and energy storage systems (ESSs), instead of fossil fuels, to provide the required power in the ferry boats. In general, full-electric ferry (FEF) boats are a new concept to reduce the cost of fossil fuels and air emissions. Hence, FEF can be regarded as a kind of dc stand-alone microgrid with constant power loads (CPLs). This article proposes a new structure of a FEF ship based on RESs and ESSs. In order to solve the negative impedance induced instabilities in dc power electronic based RESs, a new intelligent single input interval type-2 fuzzy logic controller based on sliding mode control is proposed for the dc-dc converters feeding CLPs. The main feature of the suggested technique is that it is mode-free and regulates the plant without requiring the knowledge of converter dynamics. Finally, we conduct a dSPACE-based real-time experiment to examine the effectiveness of the proposed energy management system for FEF vessels.
For more than a century, conventional marine vessels spatter the atmosphere with CO2 emissions and detrimental particles when operated by diesel motors/generators. Fuel cells have recently emerged as one of the most promising emission-free technologies for the electrification of ship propulsion systems. In fuel cell-based ship electrification, the entire marine power system is viewed as a direct current (DC) microgrid (MG) with constant power loads (CPLs). A challenge of such settings is how to stabilize the voltages and currents of the ship’s grid. In this paper, we propose a new modified backstepping controller to stabilize the MG voltage and currents. Finally, to study the performance and efficiency of our proposal, we run an experiment simulation using dSPACE real-time emulator.
Although prevention of incidents leading to evacuations at sea is of vital importance, little is known about its causal patterns and demographic determinants. We investigated therefore relationships between age, occupation and nationality and causes of evacuations. The data were obtained from the Telemedical Assistance Service (TMAS) in Denmark between 2004 and 2014 supplemented with data on all seafarers from the Danish Maritime Authority (N = 73,344). These data included information on broad age groups, occupational position and nationality. The outcomes were evacuations from any cause and in four broad categories of causes leading to evacuations. A total of 403 evacuations were reported in the 11-year study period. 27% of the evacuations were due to external causes, 19% due to diseases of the circulatory system, 14% due diseases of the digestive system and 40% from other or undetermined causes. Age-adjusted all-cause evacuation rates varied between 1.4 and 3.4 incidents per 1000 person-years in 2004–2014 for officers and between 3.3 and 20.2 incidents for non-officers. An elevated risk of evacuations was found among both officers and non-officers aged ≥50 years, compared with those aged 30–49 years with odds ratios of 2.73 (95% confidence intervals 1.66, 4.50) and 2.59 (2.03, 3.31), respectively. The odds ratios for non-officers from non-Danish European Union and from non-European Union countries compared with Danish non-officers were 1.51 (1.12, 2.04) and 0.55 (0.42, 0.71), respectively. In conclusion, working as non-officer, older age and non-Danish EU nationality were associated with a higher risk of evacuations irrespective of the cause leading to evacuation.
Background: Limited access to medical care can be considered as an occupational risk of seafaring and it may predispose to developing community-acquired pneumonia (CAP) requiring hospital care. We sought to investigate the risk for CAP and other lower respiratory tract infections (LRTI) requiring hospital care among seafarers. We examined the length of hospital stay (LOS) as a proxy for severity of illness. Methods: The study population in this panel data analysis were all seafarers and a 20% random sample of economically active individuals aged 18–65 years who were residing in Denmark in 1997–2016, constituting more than 11 million person-years of follow-up. Annually-registered socio-demographic and work characteristics were linked to data on cause of hospital admissions. We used fixed-effects and zero-truncated Poisson regression to estimate the rate ratios of hospitalization for CAP and other LRTI, and compared LOS across the two populations. Results: The adjusted incident rate ratio (IRR) for CAP in seafarers compared to the economically active population was 1.42 (95% confidence interval [CI]: 1.15–1.77), whereas the IRR was 0.73 (95% CI: 0.38–1.42) for other LRTI. For LOS, the IRRs for CAP and other LRTI in seafarers were 1.08 (95% CI: 1.04–1.12) and 0.92 (95% CI: 0.83–1.01), respectively. Conclusions: Our findings indicate that seafaring was associated with an increased risk for CAP requiring hospital care. Limited access to health care may be an important contributing factor.
Objectives Characterisation of worker injuries on board merchant ships is modest. Using telemedical service contacts in Denmark, we describe the worker injuries patterns and factors related to injury incidence. Methods The data for this study were based on contacts (n=1401) from ships to Telemedical Assistance Service (TMAS) in Denmark in 2004–2014, which were supplemented with data on the annual estimation of all seafarers from the Danish Maritime Authority (n=73 336). The final data included information on broad age groups, occupation and nationality. The outcomes were injuries from any cause and six broad categories of injuries characterised by anatomic location or type of injury. Results During the observation period of 11 years, there were 1401 contacts to TMAS due to injuries, of which 36% were in upper limb, 18% in lower limb and 13% in the head. Age-adjusted incidence rates for all injuries varied between 13.6 and 26.8 incidences per 1000 person-years in 2004–2014. In most types of injuries, younger and older seafarers had higher risk for injuries than seafarers aged 30–49 years. Depending on the type of injury, non-officers had threefold to fivefold increased odds of injuries compared with officers, the risk being highest for head injuries with an OR of 5.00 (95% CI 3.19 to 7.83). Non-officers from the European Union (EU) had higher risk in most types of injuries than non-officers from outside the EU, whereas the pattern of this risk was inverse among officers. Conclusions These findings suggest that non-officers and European seafarers have an increased risk for several types of injuries on board Danish-flagged merchant ships. Additionally, age affected risk with the younger (<30 years) and older (>50 years) seafarers having increased risk.
Marine autonomy research has focused on algorithmic and technical developments, targeting autonomous craft in restricted areas where international rules and regulations are not prioritised. This paper addresses the system engineering aspect of a highly complex system in which the seamless, predictable, and secure interoperability of vendorspecific hardware and software subsystems is a fundamental requirement for designing and implementing cyber-physical systems with artificial intelligence to assist or replace the navigating officer, such as autonomous marine surface vehicles. It addresses international rules in the sector and exhibits a system architecture that can fulfil the criteria for safe behaviour in foreseen occurrences and the capacity to request human aid if the autonomous system cannot manage a problem. The system thinking and engineering provided in this article have been applied to The GreenHopper, a harbour bus currently under construction and intended to undergo certification and enter commercial service.
Autonomous marine surface vehicles rely on computer systems with computer intelligence making decisions to assist or replace the navigating officer. A fundamental requirement for the design and implementation of such a cyber-physical system is seamless, predictable, and secure interoperability between vendor-specific hardware and software subsystems. The article describes a system design that includes mechanisms to mitigate the risks and consequences of software defects, individual component malfunction, and harmful cyber interference. It addresses international regulations in the field and demonstrates a system design that can meet the requirements for safe behaviour in foreseeable events while also having the ability to call for human assistance if the autonomous system is unable to handle a situation. The paper presents a design for highly automated vessels with several inherent risk-reducing features, including the ability to isolate and encapsulate abnormal behaviours, built-in features to support resilience to unexpected events, and mechanisms for internal defence against cyber-attacks. The article shows how this is provided by a novel middleware that supports risk mitigation, dependability, and resilience.
Autonomous systems strive to obtain salient features that include computer intelligence for obtaining situation awareness, decision support to a human navigator, or for facilitating autonomous decision-making in unmanned vehicles. This paper considers the case of autonomous marine surface vehicles, where high-quality decision support will be instrumental for obtaining a periodically unattended bridge and for approval of unmanned bridge operation with fallback through remote operation. The proposed design focuses on a sovereign-based architecture that facilitates safety, resilience and cyber-security. We address central elements of risk in the development and approval of autonomous systems; we analyze the challenges associated with testing, commissioning and maintenance of a highly complex cyber-physical system, and describe design principles for the sovereign agents architecture.
Autonomous surface vessels comprise complex automated systems with advanced onboard sensors. These help establish situation awareness and perform many of the complex tasks required for safe navigation. However, situations occur that require assistance by a human proxy. If not physically present on board, information digestion and sharing between human and machine become crucial to maintain safe operation. This paper addresses the co-design of on-board systems and a Remote Control Centre (RCC). Using the international regulations on watch-keeping (STCW) as a basis, the paper discuss how an autonomous system is designed to meet the STCW requirements. It is discussed how the autonomous system is made aware of the state of the vessel, its surroundings, on-board defects or navigational challenges and shared with the RCC in a collaborating system perspective.