Measurements Of Physical Properties Of Mixtures Related TPA Manufacture And Study Of Viscometer On High Temperature And Pressure

Terephthalic acid (TPA) is the main raw material in the manufacturing polyesters. The level of the technology in producing TPA affects development of polyester industry. It is necessary to obtain the basic physical properties and thermodynamics properties for developing new process of TPA or renovating old equipment and process. Owing to technological monopoly, all these basic properties about TPA design can't find in literature. So the physical properties of mixtures related TPA were measured and presented. This project is supported by China Petrochemical Corporation.In the paper, more than 1500 data points about the densities and viscosities and capacities for five binary systems related TPA at atmospheric pressure were measured using the pycnometer, Ubbelohde viscometer and the differential scanning calorimeter.These properties were calculated and correlated. The correlated equations were obtained for these binary systems. It is useful and important for engineering and technology design.TPA is manufactured under pressure condition. Comparing atmospheric pressure, it is more difficult to measure the physical properties at high pressure. The data are scarce in literature. In this paper, the design and manufacture of the vibrating-wire viscometer were presented which was especially suitable for the measurement of densities and viscosities under high temperature and pressure. Two kinds of properties could be obtained by one experiment. The accuracy of density to the new viscometer is equal to or higher than the high pressure PVT method. The precision of viscosity measurements is higher than the falling ball or rolling ball viscometer. It is labor saving and facility.In the world, there are only few universities possessing the technology of using vibrating-wire viscometer to measuring density and viscosity. The disadvantages of the literature's configurations were reformed. The permanent magnets are now mouthed at the exterior of the high-pressure vessel and are no longer in contact with the fluid sample. So this construction of equipment decreases the contamination of each other. Concerning the temperature-control system, the present instrument employs one non-vibrating new technology. In the high pressure systems, a simple and fast high-pressure pump was used to generate hydraulic pressure. This equipment is more easy to control than the literature's methods. A digital lock-in amplifier has been used as sinusoidal current function generator and the induced signal detector. Electrical layout is considerably simpler, and has a high accuracy. At same time, a new part that is used to adjust the direction of vibrating-wire is added.The viscosities and densities of nine pure hydrocarbon and aromatics were measured at different pressures and temperatures. At the same time the properties of a binary mixture of cyclohexane with p-xylene has also been measured. The significance of this work was to supply and perfect the data bank of n-pentane, n-hexane, benzene, ethylbenzene at the high pressures and temperatures.The experimental results were necessary for TPA manufacture and design.