Pressure dual systems

Linde dual-pressure system, precooled to 228 K, observed — 3580 0.201... 

Pressure measurement for piping and vessels is achieved by the installation of dial indicators or by distributed control systems. The piping and vessels are tapped at the required location and furnished with a 3/4-in threaded or flanged conneaion and a block valve. Tbe dial indicator is screwed into the block ralve if a remote readout system is required, the valve becomes the sensing connection. Like the thermocouple, the dial can be either fixed or swivel-headed to fecilitate readout. A dual local indicator and transmitter s) em needs only one tapping point. Exhibit 14-9 depicts a typical pressure gauge and a dual-pressure system hookup. 

Another modification of the basic Claude cycle is the dual-pressure Claude cycle, similar in principle to the Linde dual-pressure system presented in Fig. 4.8. In this dual-pressure cycle, shown in Fig. 4.17, only the gas that is sent through the expansion valve is compressed from the low pressure to the high pressure this reduces the w ork requirement per unit mass of gas liquefied. To illustrate the advantage of the Claude dual-pressure cycle over the Linde dual-pressure cycle, Barron has shown that, in the liquefaction of air, the liquid yield can be doubled while the work per unit mass liquefied can... 

Develop a plot that provides the work required to liquefy a unit mass of nitrogen in the Linde dual-pressure system of Fig. 4.8 as a function of the intermediate pressure for intermediate flow rate ratios, m,/m, of 0.5, 0.6, 0.7, and 0.8. The lower and upper operating pressures of the liquefier are 0.101 and 30.3 MPa, respectively. Assume isothermal and reversible compression at 300 K for the compressors and 100% effectiveness for the heat exchanger. 

A Linde dual-pressure system is used to liquefy air. The high-pressure air leaves the compressor at 20.2 MPa and is cooled to 293 K before entering the counterflow heat exchanger. The returning intermediate pressure air stream leaves the three-channel heat exchanger at... 

Fig. 1. Simplified flow diagrams for H2S/H2O heavy water processes, (a) Dual-temperature system where the pressure is 1.90 MPa (b) siagle-temperature...

Self contained dual agent systems, (foam/water and dry chemical), are provided for manual fire fighting efforts against three dimensional pressure leaks and large diameter pool fires. The design affords fast fire knockdown, extinguishment and sealant against re-flash. A skid... 

As for all trace-level analyses, sample preparation and handling are of crucial importance. In addition to all the usual problems of GC-MS, measurements of isotope ratios must ensure that none of these steps introduce any isotope discrimination. Any chemical reactions, including conversion of the organic sample molecules to the simple gases which are those actually analyzed, must be quantitative (100% conversion) to avoid kinetic isotope effects [627]. Until relatively recently, all gas IRMS experiments employed a dual-inlet system to permit switching between sample and standard C02 contained in two bellows containers. The pressures in the two bellows are adjusted to be equal and,... 

Small variations in apparent isotope ratio are observed when inlet pressure changes. Therefore IRMS dual inlet systems are equipped with bellows mechanisms (Fig. 7.9) so that inlet pressures of both sample and standard can be adjusted to be the same. Furthermore, small systematic changes, if any, in the measured isotope ratio as the measurement progresses are compensated by appropriate interpolation. Both these corrections are handled automatically by the software which controls the modern IRMS. 

In the single-pressure and dual-pressure processes, the catalyst volatilizes at a rate determined by the converter exit-gas temperature. Experimental work indicates that the rate loss of catalyst (without a catalyst recovery system) is approximately three times more rapid at 973°C than at 866°C (Ref. PT18). From plant operation data, the loss from a dual-pressure converter (operating at 866°C) is estimated at about 0.10 g/tonne of 100% acid, and from a single-pressure converter (operating at 937°C) it is estimated at about 0.38 g/tonne of 100% acid. 

In the dual-numbering system, one number refers to the valve design-type, and the other refers to its location and service. The first number, identifying the equipment, is unique to the SRV and is retired once the valve is taken out of service. Equipment records include information on the orifice size, set pressure, manufacturer, model number, serial number, and inlet and outlet flange sizes and ratings. 

Figure 4 Schematic diagram of high-pressure liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) system with dual-inlet system for isotope dilution analyses. (From Ref. 32.)...

Fig. 22.18. Dual-pressure nitric acid plant. (Reproduced by permission of Monsento Enviro-Chem System, Inc.)...

Whereas a dual-pressure plant or a high-pressure, single-pressure plant (with high pressure absorption) may give acceptable emission levels, the medium-pressure absorption plant must be followed by an abatement system.97... 

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