An investigation into catalysts to improve the low temperature performance of an SCR

Selective catalytic reduction with NH3 is considered as one of the most effective technologies controlling NOx emission. Metal Fe based catalysts were used in the investigation to improve the low temperature performance of NOx conversion. The temperature range studied was between 150 degrees C and 350 degrees C with the interval of 50 degrees C. The honeycomb catalysts were prepared by an impregnation method. The study also included characterization of catalysts by BET, XRD, H2-TPR, SEM and XPS methods. It is found an increase in metal Fe content from 2 to 6 % wt. offers an improvement in the catalytic performance. However, a further increment in Fe content will result in a decrease in its performance. More than 90 % NOx conversion rate could be achieved over the Fe-based honeycomb catalyst at a low temperature by doping with Ni and Zr metal with different weights. Among all the catalysts studied, the mixed metal catalyst of Fe-Ni-Zr is found the most potential one, not only because of its higher NOx conversion rate at a low temperature, but also because of its wider operation temperature window. The effect of gas hourly space velocity (GHSV) was also investigated in the study and results show as GHSV increases that reduction of NOx is decreased

A case ship study on practical design and installation of carbon absorption and solidification system

Onboard carbon capture and storage is an excellent solution to reduce the greenhouse gas emissions from shipping. This paper focuses on a case ship study on design and installation of a practical carbon absorption and solidification system which was proposed in authors’ previous work (Peilin and Haibin, 2014). The design process is based on authors’ previous work of simulation on lab-scale experiment. The specifications of the selected ship will be presented and utilized for its modelling. The processes of simulation illustrate modifications of simulation model, design of physical model, application of orthogonal design method, introduction of equipment and software and analysis of results. This paper also presents tank design, positioning and CAD drawing of the system on board after all processes and systems are derived. This paper demonstrates general processes of carbon absorption and solidification system design for a case ship so that design of the system for a new ship could follow the same procedures

Analysis on numerical simulations of CO2 absorption process of carbon solidification system

Carbon dioxide (CO2) emission control has been a popular topic since global warming affects our living conditions on the planet. Carbon Capture and Storage (CCS) is a feasible solution for mitigating the global warming effect by capturing the CO2 from power stations and industrial processes and storing them underground. There are great many of active CCS projects onshore. International Maritime Organization (IMO) has adopted guidelines for CO2 emission control by improving ship energy efficiency. The project is aiming to apply CCS on ships by capturing the CO2 emission from the engine exhaust gases and solidifying them for easy storage. It will enable ships to comply with various regional and international CO2 emission regulations and also maintain the efficiency of waterborne transportation. The simulation of carbon absorption develops and investigates the multiphase reaction model in CFD software, focusing on bubble column effect with chemical reaction. This paper presents the analysis of the numerical simulation of the CO2 absorption process. Simulation results illustrate the pressure distribution of solution and gas path and velocity in solution. This numerical simulation results also indicates the impact of environment temperature on chemical reaction rate. A comparison between experiment and simulation results is presented to figure out the impact of initial NaOH solution concentration on gas absorption process. An optimized NaOH solution concentration is figured out and will be used for further practical design of absorption system for ships

CFD simulations of absorption reaction in carbon solidification processes

Carbon capture and storage (CCS) is a promising task solution for reduction of CO2 emission from ships. To meet the IMO proposed target of 20% CO2 reduction from shipping by 2020, proposal of solidifying CO2 separated from engine exhaust had been made and tested by the authors. Laboratory experiment [1] on CO2 absorption has illustrated the feasibility of solidifying carbon onboard ships. To further verify the accuracy of results from CO2 absorption experiment, simulation with computational fluid dynamics (CFD) of the CO2 absorption and solidification processes is carried out, including system modelling and meshing, reactions simulating and post-CFD treatments. Eulerian multiphase model and species transport model are applied for the simulation. These models will present the interaction between gas phase (CO2) and chemical solution in both physical phase interactions and chemical reactions between the species. The mass fractions of Na2CO3 in solution are monitored during the absorption process. Conclusions has been reached that the simulation results have a good agreement with the experiment results

A life cycle assessment on carbon capture and solidification method on ship

Greenhouse gas reduction has become a severe topic in the shipping industry and researchers are striving to investigate different GHG reduction technologies to determine their feasibility especially on the environment impact. However, there is no specific evaluation process currently available so this paper presents a Life Cycle Assessment for a carbon emission reduction method to introduce Life Cycle Assessment as a systematic evaluation approach which can guide policy makers to evaluate the performances and help ship owners to select suitable reduction technologies. The carbon reduction method proposed by authors was proved to be cost effective in previous works and this paper applies life cycle analysis focusing on all stages of ship life to investigate, determine and compare the feasibility of this method. The environmental impacts are considered to be the most significant standard for the assessment. From the results of the assessment, the proposed reduction method meets the carbon reduction target and can lead to a lower global warming potential while leveling up the carbon reduction target. This paper also indicates, to achieve carbon reduction target set up by regulations, a marginal target will be necessary due to the energy requirement and efficiency of the method/system as well as the consideration of activities in different life stages. It is also recommended that the evaluation of carbon reduction method could apply Life Cycle Assessment so that policy makers and ship owners are provided with comparable results for reasonable decision makings

Development of a dynamic programming method for low fuel consumption and low carbon emission from shipping

Fuel saving and low carbon emission in shipping have already become an attractive and important subject in the shipping industry driven by the increasing full oil price and considerations of reduction of green house gas emission. Global shipping consumes 200 million tons of liquid fuel, resoluble for 1.12 billion tons of CO2 emission in the world. This paper presents the development of a novel forward dynamic programming method to optimise ship’s fuel consumption with respect to safety during a voyage. The constraints are weather, sea conditions and the safety constrains defined in the IMO guidance MSC.1/Circ.1228. Compared with the traditional dynamic programming methods, the newly developed weather routing method is more accurate and practical. Simulation results from a case study have shown that the newly developed method is able to save several tons of fuel compared with that of the traditional methods for one North Atlantic voyage. As a result, it can offer much CO2 emission reduction

Reviews on current carbon reduction technologies and experimental and numerical analysis on financial feasibility and practical application of a carbon absorption method

Global warming has become a popular topic and IMO’s regulations have come in forces to reduce carbon emission from international shipping by improving the energy efficiency with EEDI and EEOI. Carbon capture and storage is an alternative method utilizing different technologies to capture the CO2 from emission sources and storage/utilize them to reduce the carbon emission from exhaust gas or the content of CO2 in atmosphere. This paper reviews current carbon capture method and introduces a chemical absorption technology for carbon reduction on ships, which is a feasible method and applied by onshore industry. Experimental analysis indicates the average absorption rate for carbon dioxide feed in can reach 68%. A financial analysis is presented to evaluate a case ship in comparison with liquefaction method which indicates the absorption method is cost effective and earns profit after selling the final product from the chemical processes at the destination of a voyage. This paper also presents the design, analysis and validation of the numerical simulation model and a case ship study of practical absorption system installation is conducted based on the validated model