Economic system schematics

Pig. 10. (a) Pressure-enthalpy diagram and (b) system schematic for a system with flash economizers. 

Schematic description of economic systems, following Figure 13.3 (a) Classical, (b) environmental, and (c) sustainable economic systems.

In general, radioscopic X-ray inspection systems are used in the serial examination of industrial workpieces since they enable a flexible adjustment of the beam direction and of the inspection perspective as well as on-line viewing of the radioscopic image. In the past few years this economic and reliable method has become prevalent in weld inspection during the manufacturing process of pipes. The configuration of such radioscopic systems is schematically represented in fig. 1. 

Air stripping is used to remove 90% of the toluene (molecular weight = 92) dissolved in a 10 kg/s (159 gpm) wastewater stream. The inlet composition of toluene in the wastewater is 500 ppm. Air (essentially free of toluene) is compressed to 202.6 kPa (2 atm) and bubbled through a stripper which contains sieve trays. In order to avoid fire hazards, the concentration of toluene in the air leaving the stripper is taken as 50% of the lower flammability limit (LFL) of toluene in air. The toluene-laden air exiting the stripper is fed to a condenser which recovers almost all the toluene. A schematic representation of the process is shown in Fig. 2.11. Calculate the annual operating cost and the fixed capital investment for the system. The following physical and economic data are available ... 

In the aforementioned closed loop water system the polluted process water is purified completely in one wastewater treatment scenario. Only one type of process water is produced for reuse. In practise several types of process water are needed, and also several types of polluted wastewater streams are produced. This is schematically shown in Figure 2. In that case it can be advantageous in technical, economic and environmental respects to include several closed loop water systems within one production line. 

The recent availability of economical, stable and high-resolution pressure transducers has led to the development of a new type of helium pycnometer which offers extreme simplicity of operation along with great speed and accuracy. A schematic diagram of this pycnometer is shown in Fig. 21.1. The volume in the shaded area is considered the sample cell. After purging the system with helium and bringing all volumes to ambient pressure, the sample cell is pressurized to P2> about 15 psi above ambient. Valve is opened to connect the additional volume to that of the cell. 

The pervaporation process to separate liquid mixtures is shown schematically in Figure 9.1. A feed liquid mixture contacts one side of a membrane the permeate is removed as a vapor from the other side. Transport through the membrane is induced by the vapor pressure difference between the feed solution and the permeate vapor. This vapor pressure difference can be maintained in several ways. In the laboratory, a vacuum pump is usually used to draw a vacuum on the permeate side of the system. Industrially, the permeate vacuum is most economically generated by cooling the permeate vapor, causing it to condense condensation spontaneously creates a partial vacuum. 

Figure 7 shows a schematic diagram of the model calciner used for studying an economic continuous two-stage calcining system. The exhaust gas from first stage kiln is fed as fuel for second stage kiln. 

Figure 2. Skeleton schematic of 1976 system available-energy flows (megawatts). The unit costs of steam and electricity were computed using the equality method and a capital charge of 9.0(10 ) at an effective after-tax interest rate of 8.5% and an economic life of 20 years.

Figure 10.1. Schematic representation of the processing window for the extrusion process. The four curves identify limits to the process Une 1 indicates the maximum screw rotation speed, curve 2 represents the torque limitation of the drive system (region to the right and below of curve exceeds the allowable torque on the drive system), curve 3 represents the maximum temperature allowable to avoid the thermal degradation, and Une 4 shows the minimum screw rotational speed to provide the minimum throughput, acceptable by the process economics.

An economic analysis of a superheated-steam drying of aluminum oxide from 40% to 2% moisture content and an output of2000 kg/h showed that the optimum inlet vapor temperature into such a dryer is 374°C [59]. The dryer cost was lower than that of a comparable air dryer, and the operating costs were lower by about 15%. Figure 54.11 shows a schematic diagram of a superheated drying system in a sugar factory [61]. 

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