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The effect of important parameters on the natural gas vehicles driving range

Farzaneh-Gord M., Rahbari H.R., Nikofard H.

Polish Journal of Chemical Technology

2012

Vol. 14, nr 4

61-68

One of the most important issues regarding Natural Gas Vehicles (NGVs) is the Driving Range, chich is defi ned as capability of a NGV to travel a certain distance after each refueling. The Driving Range is a serious obstacle in the development and growth of NGVs. Thus the necessity of studying the effects of various parameters on the Driving Range could be realized. It is found that the on-board storage capacity and the natural gas heating value have the greatest effect on the Driving Range. The charge mass of NGV cylinders is varied due to the natural gas composition and the fi nal in-cylinder values (temperature and pressure). Underfi lling of NGV cylinders, during charging operations, is a result of the elevated temperature which occurs in the NGV storage cylinder, due to compression and Rother processes could be overcome by applying extensive over-pressurization of the cylinder during the fuelling operation. Here, the effects of the most important parameters on the Driving Range have been investigated. The parameters are natural gas composition, engine effi ciency and fi nal NGV on-board in-cylinder temperature and pressure. It is found that, the composition has big effects on the Driving Range. The results also show that as fi nal in-cylinder pressure decreases (or temperature increases), the Driving Range will be increased.

Developing novel correlations for calculating natural gas thermodynamic properties

Farzaneh-Gord M., Rahbari H.R.

Chemical and Process Engineering

2011

Vol. 32, nr 4

435-452

Natural gas is a mixture of 21 components and it is widely used in industries and homes. Knowledge of its thermodynamic properties is essential for designing appropriate processes and equipment. This paper presents simple but precise correlations of how to compute important thermodynamic properties of natural gas. As measuring natural gas composition is costly and may not be effective for real time process, the correlations are developed based on measurable real time properties. The real time properties are temperature, pressure and specific gravity of the natural gas. Calculations with these correlations are compared with measured values. The validations show that the average absolute percent deviation (AAPD) for compressibility factor calculations is 0.674%, for density is 2.55%, for Joule-Thomson coefficient is 4.16%. Furthermore, in this work, new correlations are presented for computing thermal properties of natural gas such as enthalpy, internal energy and entropy. Due to the lack of experimental data for these properties, the validation is done for pure methane. The validation shows that AAPD is 1.31%, 1.56% and 0.4% for enthalpy, internal energy and entropy respectively. The comparisons show that the correlations could predict natural gas properties with an error that is acceptable for most engineering applications.