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Constructional changes of pneumopercussion machines for improving their efficiency

100%

Antonchik V. , Zabolotnyi K. , Hankevich V. , Maltseva V. , Kuts O. , Dyczko A.

tom vol. 40, iss. 4

206--215

Pneumopercussion machines (pneumatic impact machines) are widely used in all areas of human activity. Also, they are widely used in the mining industry. Unfortunately, their operation is characterized by a low efficiency of compressed air energy usage. In some cases, this level of efficiency is calculated as 15-20%. Such a situation increases the cost of drilling operations significantly. In this article, due to an implementation of a new construction of the equipment, the efficiency of the pneumopercussion machines was increased. This problem is solved by combining the most effective thermodynamic processes of compressed air in the working chambers of machines. Also, a new technical solution for the construction of pneumopercussion machines is suggested by the Authors. The proposed new design is realized by a combination of the most effective thermodynamic processes in the chambers of pneumatic impact machines. A new pneumatic hammer is presented, which allows to reduce compressed air consumption twice during an operation on the surface (in comparison with hammers available on the market). The operation of pneumopercussion machines and the method of calculating geometric parameters are described. The economic performance of the equipment confirms the correctness of the proposed technological solutions.

Phase equilibria for liquefi eld natural gas (LNG) as a multicomponent mixture

75%

Włodek T.

tom Vol. 32, no. 3

539--550

Liquefied natural gas (LNG) has an increasingly important role in the global natural gas market. Global demand for natural gas will grow over the coming years. LNG is transported by ships to unloading points on the storage terminals. During the LNG unloading and storage processes some part of LNG evaporates into gas phase and causes changes in the composition of stored LNG. The main component of LNG is methane, the remaining components are primarily ethane, propane, butane and nitrogen. Depending on the participation of these components the basic thermodynamic parameters of LNG can significantly change. LNG is also product sensitive to changes of temperature. In order to better prediction of changes of individual paramete rs of stored LNG caused by changes of temperature and LNG composition vapor-liquid equilibrium (VLE) calculations are performed for cryogenic conditions using equations of state.