No abstract

There are excellent offshore wind resources in the ocean off the west coast of Taiwan, and renewable offshore wind power has been actively developed in recent years. This study intends to establish a cost-effectiveness assessment model to compare the pollutant emissions and cost benefits of traditional fossil fuel and fuel cells used as the propulsion force of working vessels in Taiwan’s offshore wind farms. According to MARPOL, vessels should use very-low-sulfur fuel oil (VLSFO) with sulfur content of less than 0.5 wt. %. Therefore, this study proposes two strategies: changing marine power from VLSFO to ultra-low-sulfur diesel (ULSD) and a proton exchange membrane fuel cell (PEMFC). The emission reduction and cost benefit were analyzed in comparison with the original condition when VLSFO was used. The results show that compared with the total cost of VLSFO, the total costs of Strategy ULSD and Strategy PEMFC increase by 7.5% and 51.2%, respectively, over five years. Strategy PEMFC brings environmentally friendly benefits primarily by reducing SOx, NOx, HC, PM, and CO2 emissions by 100%, 97.4%, 91.8%, 81%, and 81.6%, respectively, as compared with VLSFO. The cost–benefit ratio (CBR) of Strategy ULSD was higher than that of Strategy PEMFC in the first three years after improvements were made, and then the trend reversed. Strategy PEMFC is suitable as an alternative marine power source for the medium- and long-term (more than three years), while Strategy ULSD is suitable as a short-term investment for less than three years.

Emulsions that mix two or more immiscible phases are broadly applied in pharmaceutics, chemistry, and industries. The phase inversion temperature (PIT) method is an emulsifying approach to preparing an emulsion with low energy consumption and cheap equipment. The effects of surfactant characteristics and processes of cooling or heating on the fuel properties of emulsions composed of silicone oil by the emulsifying method, such as mean droplet sizes of the de-ionized water phase, were considered herein. The application of the silicone oil emulsion as engine fuel was first evaluated. The results show that the emulsions added with the polyol surfactant mixture appeared to have a larger mean water-droplet size, a larger number of dispersed water droplets, a wider range of dispersed-water sizes, and lower kinematic viscosity than those with Brij 30 surfactant. Increasing the surfactant concentration of either Tween 20 mixed with Span 80 or Brij 30 surfactant increased kinematic viscosity and the number of dispersed droplets while decreasing mean droplet sizes. After being subjected to fast heating and then fast cooling, the silicone oil emulsion appeared to form many smaller dispersed droplets than those being proceeded with slow cooling. The emulsion of silicone oil was found to have adequate engine fuel properties.

The effects of emulsification variables, such as surfactant type and heating/cooling emulsion processes, on the emulsification characteristics of silicone oil’s emulsions prepared by the phase inversion temperature method were investigated in this study. The water-in-oil (W/O) emulsions have been widely applied to enhance burning efficiency and reduce both pollutant emissions and fuel consumption. The silicone oil was emulsified with de-ionized water with the assistance of nonionic surfactants to form oil-in-water (O/W) emulsions. The hydrophilic–lipophilic balance (HLB) value of the Span 80 and Tween 20 surfactant mixture was set equal to 10 based on their weight proportions and the respective HLB values of the two surfactants. The experimental results show that the emulsions with the Span 80/Tween 20 surfactant mixture appeared to have a higher phase inversion temperature and a larger electrical conductance. On the other hand, it has a lower emulsification stability and a narrower range of phase inversion temperature than the emulsions prepared with a Brij 30 surfactant (polyoxyethylene (4) lauryl ether). The increase in surfactant concentration from 1 wt.% to 10 wt.% decreased the electrical conductance and phase inversion temperature while increasing the suspensibility and absorbance value for the emulsions prepared with either Span 80/Tween 20 mixture or Brij 30.