A Case Study of a Solid Oxide Fuel Cell Plant on Board a Cruise Ship

The work is a case study of a cruise ship supplied by liquefied natural gas (LNG) and equipped with a solid oxide fuel cell (SOFC). It is supposed that a 20 MW SOFC plant is installed on-board to supply hotel loads and assisting three dual-fuel (DF) diesel/LNG generator sets. LNG consumption and emissions are estimated both for the SOFC plant and DF generator sets. It results that the use of LNG-SOFC plant in comparison to DF generator sets allows to limit significantly the SOx, CO, NOx, PM emissions and to reduce the emission of CO2 by about 11%. A prediction of the weight and volume of the SOFC plant is conducted and a preliminary modification of the general arrangement of the cruise ship is suggested, according to the latest international rules. It results that the SOFC plant is heavier and occupies more volume on board than a DF gen-set; nevertheless, these features do not affect the floating and the stability of the cruise ship

Anaerobic Digestion of Olive Mill Wastewater in the Presence of Biochar

Biological treatments focused on stabilizing and detoxifying olive mill wastewater facilitate agronomic reuse for irrigation and fertilization. Anaerobic digestion is particularly attractive in view of energy recovery, but is severely hampered by the microbial toxicity of olive mill wastewater. In this work, the addition of biochar to the digestion mixture was studied to improve the stability and efficiency of the anaerobic process. Kinetics and yields of biogas production were evaluated in batch digestion tests with biochar concentrations ranging from 0 to 45 g L−1. The addition of biochar reduced sensibly the lag phase for methanogenesis and increased the maximum rate of biogas generation. Final yields of hydrogen and methane were not affected. Upon addition of biochar, soluble COD removal increased from 66% up to 84%, and phenolics removal increased from 50% up to 95%. Digestate phytotoxicity, as measured by seed germination tests, was reduced compared to raw wastewater. Addition of biochar further reduced phytotoxicity and, furthermore, a stimulatory effect was observed for a twenty-fold dilution. In conclusion, biochar addition enhances the anaerobic digestion of olive mill wastewaters by effectively reducing methanogenesis inhibition and digestate phytotoxicity, thus improving energy and biomass recovery

Preliminary Investigation of a Multi-MW Solid Oxide Fuel Cell Power Plant to be Installed on Board a Cruise Ship

As the use of both clean energy technologies and alternative fuels in the maritime sector is spreading, studies dealing with the installation of multi-MW power generation plants on board ships have been increasing. Considering this, the present work proposes a 12 MW Solid Oxide Fuel Cell (SOFC) to be installed on board a cruise ship of about 175000 gross tonnes, 345 m length, and powered by Liquefied Natural Gas (LNG). It is supposed that the SOFC generates electrical energy and provides part of the thermal power demand by integrating a heat recovery system. A zero-dimensional (0D) Aspen Plus model has been developed to optimize the onboard layout and to predict the performance of the integrated power plant. Specific parameters, such as the fuel utilisation factor, the pre-heated air temperature, the anodic recycle flow rate, and the exhaust gas temperature, have been manipulated to evaluate the overall efficiency of the integrated power plant under different operating conditions. The model has been validated by comparing the results obtained with data from literature and commercial SOFC modules. A layout configuration of the SOFC plant is suggested and the performances are investigated by varying the efficiency in the range of 60-40%

Cashew apple bagasse as new feedstock for the hydrogen production using dark fermentation process.

Cashew apple bagasse (CAB) has been studied as feedstock for the biohydrogen production using Clostridium roseum and the dark fermentation process. Pretreatment with alkaline hydrogen peroxide (CAB-AHP) on raw material and the acid and enzymatic hydrolysis have been taken into account to evaluate the H2 yields. Results show that the acid hydrolysate obtained from CAB produced higher H2 molar yield (HMY) (15 mmolH2/Lhydrolysate) than the acid hydrolysate from CAB-AHP (4.99 mmolH2/Lhydrolysate), These HMY were noticeably higher than values obtained from the enzymatic hydrolysate of CAB-AHP (1.05 mmolH2/Lhydrolysa) and the enzymatic hydrolysate of CAB (0.59 mmolH2/Lhydrolysa). The maximum biohydrogen productivity (12.57 mLH2/L.h) was achieved using the acid hydrolysate from CAB, with a H2 content of about 72% vol, that could be satisfactory in view of an energetic applications of the biogas. Results suggest that CAB could be considered for the hydrogen production process, providing an appropriate destination for this lignocellulosic biomass, and consequently, reducing the environmental impact it can exert

Biochar Enhances Anaerobic Digestion of Olive Mill Wastewater

The anaerobic digestion of olive mill wastewater is severely hindered by the microbial toxicity of the effluent. Successful biodegradation is usually attained only by dilution and mixing with other organic wastes. In this work the addition of biochar has been investigated as an alternative to co-digestion. In batch tests, raw olive mill wastewater selectively inhibited methanogenic bacteria even at 1:10 dilution. Acidogenesis was not affected and further biodegradation was hindered by acidification and high hydrogen partial pressure. Methanogenesis resumed after 20 days and ended after 40 days from inoculation. Overall soluble COD removal was 32.9% with a methane yield of 2.35 ± 0.27 L STP/L of digestion medium. Treatment of wastewater with 15% (w/v) poplar biochar removed 71% of inhibitory polyphenolic compounds and effectively accelerated the onset of methanogenesis, with a reduced duration of 26 days. Biochar treatment of olive mill wastewater followed by anaerobic digestion led to a higher soluble COD removal (61.6%) with a slightly decreased biogas yield of 1.62 ± 0.30 L STP/L of digestion medium

Study of direct methanol fuel cell for small and medium scale applications

Study of direct methanol fuel cell for small and medium scale application

Simulation Modelling of a Ship Propulsion System in Waves for Control Purpose

open5The article deals with a simulation approach to the representation of the ship motions in waves, interacting with the propulsion system behaviour (diesel engine and propeller). The final goal is the development of a simulator, as complete as possible, that allows the analysis of the main engine thermodynamics in different sea conditions and the correct management of the other propulsion components. This latter aspect is particularly interesting in some of the last new energy solutions for decarbonisation of ships, concerning for example auxiliary electric motors, powered by batteries, to support the traditional diesel mechanical propulsion (especially in heavy weather conditions). From this point of view, a proper analysis of the engine dynamic performance, affected by particular sea states, is fundamental for a smart management and control of shaft generators/auxiliary electric motors, batteries, etc... To this end, the work presents and highlights the main features of a ship simulator, suitable for the study of the new propulsion solutions that are emerging in the maritime transport. Some representative results are also reported to assess the potential of the conceived simulation approach.openMaria Acanfora, Marco Altosole, Flavio Balsamo, Luca Micoli, Ugo CamporaAcanfora, Maria; Altosole, Marco; Balsamo, Flavio; Micoli, Luca; Campora, Ug