As a functional material, high-purity single-walled carbon nanotubes are widely used in basic science and nanotechnology, such as mechanics, thermology, electricity, etc. Single-walled carbon nanotubes prepared by arc discharge method have fewer defects and are more suitable for mechanical and electrical applications; therefore, arc discharge method was adopted to prepare single-walled carbon nanotubes in this paper. Firstly, single-walled carbon nanotubes were prepared by dc arc discharge. Then, single-walled carbon nanotubes were purified by physical and chemical synthesis, after burning, acidification and selective dissolution in organic solvent, single-wall carbon nanotubes with high purity were obtained. Single-walled carbon nanotubes which purified before and after was investigated by Uv-visible-near-infrared spectroscopy, resonance Raman spectroscopy and high-resolution transmission electron microscopy.

Dimethyl ether (DME) is used primarily as a propellant and a motor fuel alternative, (DME) is miscible with most organic solvents and has a high solubility in water. Recently, the use of (DME) as a fuel additive for diesel engines has been investigated due to its high volatility (desired for cold starting) and high cetane number of 55–60, with the advantage of high efficiency, and low exhaust emissions (no particulates, no Sulphur, and low NOx). Technical-quality (DME) is an alternative to liquefied petroleum gas (LPG). The production processes included catalytic dehydration of methanol in an adiabatic fixed-bed reactor and two columns product separations. In this study, the technological process for (DME) synthesis is simulated in Aspen Hysys V3.1 based on the combined parameters of the reaction dynamic model for methanol dehydration reaction, the improved NRTL model of the liquid phase, the PR model of vapor phase was selected as the fluid package as it is able to handle selected pure components (methanol, water and dimethyl ether). The equilibrium reaction was selected to describe conversion of methanol to DME reaction and it is about 80%. A feasibility study and design of a plant producing 99.9 wt% Dimethyl ether (DME). The plant is designed which is capable of producing 50,000 metric tons of (DME) per year via the catalytic dehydration of methanol over an acid zeolite catalyst.