Application of Thermal Energy Storage to a Combined Heat and Power Plant

The present study deals with the economic and environmental benefits that can be attained through the coupling of borehole thermal energy storage (BTES) and combined heat and power (CHP). Energy prices are significantly higher during the winter months due to the limited supply of natural gas. This dearth not onlyincreases operating costs but also emissions, due to the need to burn ultra-low sulfur diesel (ULSD). The scope of this paper is to present a TRNSYS model of a BTES system that is designed using actual operational data from the campus CHP plant.

Pore-Scale Simulation of the Interaction between a Single Water Droplet and a Hydrophobic Wire Mesh Screen in Diesel

Recently, the trend towards sustainable energy production and pollution control has motivated the increased consumption of ultra-low-sulfur diesel (ULSD) or bio-fuels. Such fuels have relatively low surface tension with water and therefore, the separation of water from fuel has become a challenging problem. The separation process relies on using porous structures for the collection and removal of water droplets. Hence, understanding the interaction between water droplets and the separators is vital. The simplest geometry of a separator is the wire mesh screen, which is used in many modern water–diesel separators. Thus, it is considered here for systematic study. In this work, pore-scale computational fluid dynamics (CFD) simulations were performed using OpenFOAM® (an open-source C++ toolbox for fluid dynamics simulations) coupled with a new accurate scheme for the computation of the surface tension force. First, two validation test cases were performed and compared to experimental observations in corresponding bubble-point tests. Second, in order to describe the interaction between water droplets and wire mesh screens, the simulations were performed with different parameters: mean diesel velocity, open area ratio, fiber radii, Young–Laplace contact angle, and the droplet radius. New correlations were obtained which describe the average reduction of open surface area (clogging), the pressure drop, and retention criteria.

Physicochemical Properties Enhancement of Biodiesel Synthesis from Various Feedstocks of Waste/Residential Vegetable Oils and Palm Oil

The main aim of the present study was to improve the oxidation stability and cold flow properties of biodiesel produced from waste frying/cooking oil and palm oil. In this work, waste frying/cooking methyl ester (WFME) and palm methyl ester (PME) were prepared using an alkali-catalyzed transesterification process, and the physicochemical properties of the pure biodiesel as well as of binary blends among them were investigated. The results indicated that palm biodiesel and WFME18, produced from a mixture of frying, cooking, sunflower, and corn oils, can be used as antioxidant additives, enhancing biodiesel stability. Additionally, it was found that WFME1 and WFME12 derived from waste residential canola oil can be used as cold flow improvers for enhancing the cold flow properties of palm biodiesel. Moreover, ultra-low sulfur diesel fuel winter (ULSDFW), ultra-low sulfur diesel fuel summer (ULSDFS), kerosene (KF), and benzene (BF) were utilized to enhance the cold flow properties of the samples and meet the requirements of diesel fuel standards. The investigation of the experimental results indicated that blending WFME-PM with a low proportion of petroleum-based fuel (KF and BF) could significantly improve the cold flow properties (CP and PP) as well as oxidation stability of WFME.

Lubricity assessment of ultra-low sulfur diesel fuel (ULSD), biodiesel, and their blends, in conjunction with pure hydrocarbons and biodiesel based compounds

This research aimed to investigate the lubricity and wear properties of ultra-low sulfur diesel fuel (ULSD) blended with biodiesel and doped with biodiesel-based organic compounds. In this work, neat n-dodecane served as a surrogate for ultra-low sulfur diesel fuel (ULSD), Fischer Tropsch, and renewable diesel fuels. Additionally, some pure hydrocarbons were also investigated for unsaturation and carbon chain length. Tribological characterization was conducted on quenched and tempered AISI 4140 steel, substituting diesel fuel pump material, and using the ball-on-disc technique. The wear rates of biodiesel samples were about 2–4 times less than the vegetable oils. Esterification improves the lubricity of vegetable oils. The wear rate of biodiesel is about 5–7 times greater than that of fossil base commercial Eurodiesel fuel. Using biodiesel as an additive had a significant effect on the lubricity of pure n-dodecane, adding 2 wt% biodiesel resulted in 5–7 times wear rate reduction that equivalent to the lubricity level of commercial Eurodiesel fuel. Wear rates of pure hydrocarbons showed that wear is reduced with increasing chain length and unsaturation.