Physical flowrate

Lyachshenko number, dimensionless left hand side, dimensionless particle mass, kg pressure, N/m or force, N mass feed rate, kg/s or volumetric flowrate in mVhr drag or resistance force, N physical properties correction factor for slurries Reynolds number, dimensionless right hand side hydraulic radius, m... 

Given a number Nr of waste (rich) streams and a number Ns of lean streams (physical and reactive MSAs), it is desired to synthesize a cost-effective network of physical and/or reactive mass exchangers which can preferentially transfer a certain undesirable species. A, from the waste streams to the MSAs whereby it may be reacted into other species. Given also are the flowrate of each waste stream, G/, its supply (inlet) composition, yf, and target (outlet) composition, yj, where i = 1,2,..., Nr. In addition, the supply and target compositions, Xj and x j, are given for each MSA, where j = 1,2, Ns. TTie flowrate of any lean stream, Ly, is unknown but is bounded by a given maximum available flowrate of that stream, i.e.. 

The relationship between pressure gradient in a pipe and the flowrates and physical properties of the phases. 

The polytropic efficiency is a function of the physical properties of the gas and the machine design. Generally, the higher the feed flowrate, the higher the polytropic efficiency of the compressor. A first estimate of the polytropic efficiency of a centrifugal compressor can be obtained from ... 

Example 15.2 A crude oil stream is to be preheated by recovering heat from a kerosene product in a shell-and-tube heat exchanger. The flowrates, temperatures and physical properties (at the mean temperatures) are given in Table 15.5. 

The constants in the heat transfer and pressure drop correlations are functions of the fluid physical properties, volumetric flowrate, tube size and pitch. In preliminary design, it is reasonable to assume either 20 mm outside diameter tubes with a 2 mm wall thickness or 25 mm outside diameter tubes with 2.6 mm wall thickness. The tube pitch is normally taken to be pj = l.25do- A square tube pitch configuration can be assumed as a conservative assumption. Baffle cut can be assumed to be 0.25 in preliminary design. 

A processing plant is a physical system containing a large number of units and streams. For example, counting the equipment in the processing section as well as in the service section (considering mixers and stream dividers) of a petrochemical plant reveals the existence of approximately 1000 interconnected units and about 2500 streams. If we also take into account that in each stream the variables of interest can be flowrate, composition, temperature, pressure, and enthalpy, it is evident that data treatment in a typical plant involves the solution of a large-scale problem. 

In practice, it is sometimes possible to incorporate moving blades in the filter equipment so that the thickness of the cake is limited to the clearance between the filter medium and the blades. Filtrate then flows through the cake at an approximately constant rate and the solids are retained in suspension. Thus the solids concentration in the feed vessel increases until the particles are in permanent physical contact with one another. At this stage the boundary between the slurry and the cake becomes ill-defined, and a significant resistance to the flow of liquid develops within the slurry itself with a consequent reduction in the flowrate of filtrate. 

The efficiency of the individual plates is expected to depend on the physical properties of the mixture, the geometrical arrangements of the trays, and the flowrates of the two... 

Besides the two olfactometers used by IMAG, a third olfactometer owned by the organisation of applied physical research in the Netherlands (TNO) participated in the experiments. The flowrate of this olfactometer amounts to 20 1/min. Flowrate experiments carried out by TNO show a distinct difference of inhaled concentration. This affirms the results obtained by Dravnieks (1). Using the TNO results a difference of 2.4 may be expected between the results of an olfactometer with a flowrate of 5 1/min and one with a flowrate of 20 1/min. These values represent the lowest and highest flowrates of olfactometers used in the comparative odour research. The observed factor based upon the pooled data was 2.41. 

The model is seen to be a series sequence of N equal sized CSTRs which have a total volume V and through which there is a constant flowrate Q. From the physical standpoint, it is natural to restrict N, the number of tanks, to integer values but, mathematically, this need not be the case. When N is considered as a continuous variable which lies between one and infinity, a model results which can be used to interpolate continuously between the bounds of mixing associated with the CSTR and PFR. For N less than unity, the model represents systems with partial bypassing [41]. For integral values of N eqn. (43) may be inverted directly (see Table 9, Appendix 1) to give... 

In the laboratory, tubular reactors are very convenient for gas-phase reactions, and for any reaction which is so fast that it is impractical to follow it batchwise. Measurements are usually made when the reactor is operating in a steady state, so that the conversion at the outlet or at any intermediate point does not change with time. For fast reactions particularly, a physical method of determining the conversion, such as ultra-violet or infra-red absorption, is preferred to avoid disturbing the reaction. The conversion obtained at the outlet is regulated by changing either the flowrate or the volume of the reactor. 

Note that to continue further with the design of the reactor by taking a value of fA from Fig. 4.3, or using equation 4.15 or 4.17, requires a knowledge of and a for the bubble dispersion as well as a more exact value of kL. These will depend on the type and configuration of the reactor chosen, the flowrates at which it is operated and the physical properties of the chemical species involved. 

A numerical example might be useful to illustrate some of the issues discussed above. The base case reactor is used with a design conversion of 80% and reactor temperature of 320 K. The diameter of the reactor is 5 m, and the jacket area is 160 m2. With a perfectly mixed circulating cooling water system, the jacket temperature is 304 K and the flowrate of makeup cooling water is 50.8 kg/s. The physical properties of the reaction liquid are... 

One important physical property assumption is made about heat capacities. The mass heat capacities of all components are assumed to be the same (2kJkg-1 K-1). This means that the product of the mass flowrate and the mass heat capacity is constant for any stream and equal to the sum of the product of the component molar flowrates times the corresponding molar heat capacities. Thus, despite the fact that molar flowrates of individual components vary down the length of the reactor, the term F Ylf=A yjcpj is constant, where F is the total molar flowrate, y - is the mole fraction of component j, and cpj is the molar heat capacity of component j. This relationship is used in the design procedures discussed below to calculate the inlet flowrate from an energy balance around the reactor. 

The control structure shown in Figure 6.57 is installed on the flowsheet. The feed is flow-controlled. The outlet temperature is controlled by manipulating the coolant flowrate. Note that the OP signal is sent to both of the control valves on the coolant stream, opening and closing them simultaneously. The setup works in the simulations, but it is not what would be used in a real physical system. A pressure-driven simulation in Aspen Plus requires that valves be placed on both the inlet and outlet coolant streams. In a real system, the cooling water would be drawn from a supply header, which operates a fixed pressure. A single control valve would be used, either on the inlet or on the outlet, to manipulate the flowrate of coolant. 

Physical parameters (P) column length, flowrate, particle size, column diameter (packed columns). 

We see, then, two distinct kinds of plate height terms for the mobile phase a term HD proportional to flow velocity v, valid when diffusion terminates a molecule s velocity bias, and a velocity-independent term Hfy valid when flow terminates the bias. The question yet unanswered is how HD and Hf combine in contributing to the overall experimental plate height. Plate heights are usually additive because variances (for independent processes) are additive it is tempting to apply the additive rule here. However, additivity does not apply to HD and Hf. We see this in simple physical terms by looking at two extremes of flowrate. 

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