The measure of volumetric flow rate is utilized to calculate sampling volume and airborne concentration in integrated air sampling. Consequently, calibration of the sampling train to verify volumetric flow rate is critical. The relation between sampler Pressure drop and volumetric flow rate was studied in support of using the former rather than the latter for the calibration of sampling trains. Four types of respirable cyclones, two filter brands with membrane samples of the same and different lots of production, and two personal pump types were considered as components of the sampling trains under consideration. Volumetric flow rate and Pressure drop were measured under controlled conditions in a cylindrical jar designed for these determinations. For all the configurations considered, the relation between sampler Pressure drop and standard volumetric flow rate was linear. Intra-sample selection of cyclones of the same type and pump type did not create significant differences in sampler Pressure drop. Filter selection, regardless of brand or production lot, did create linear response functions that had statistically different slopes and intercepts. When grouped by cyclone type and filter brand, the sampler Pressure drop at the flow rate recommended by the cyclone’ s manufacturers showed variability that was not normally distributed. The recommended central tendency estimate of Pressure drop is the median value, with point estimates that should be specific to a cyclone type / filter brand combination.

This paper presents a steady state one-dimensional two-fluid model for gas-solid two-phase flow in a vertical riser. The model is solved using conservative variable approach for the gas phase, and fourth order Runge-Kutta method is used for the solid phase. The model predictions for Pressure drop are compared with available experimental data and with Eulerian-Lagrangian predictions, and a good agreement is obtained. The results indicate that the Pressure drop increases as the solid mass flow rate, particle size, and particles density increase. In addition, the model predictions for minimum Pressure drop velocity are compared with experimental data from literature and the mean percentage error. MPE for minimum Pressure drop velocity is-9. 89%. It is found that the minimum Pressure drop velocity increases as the solid mass flow, particle size and particle density increase, and decreases as the system total Pressure increases.

KATAPAK-S is a type of structured catalytic packing, which is used in reactive distillation processes. The dry Pressure drop characteristic (the Pressure drop in the absence of liquid flow) is of significant importance for the investigation of process hydrodynamics. In this paper, the dry Pressure drop within the catalyst packed channels of KATAPAK-S has been investigated using Computational Fluid Dynamics (CFD).Results of the CFD simulations were validated using experimental Pressure drop data and empirical correlations. The CFD results showed an excellent agreement with theoretical and experimental data.

Although two-phase flow is frequently encountered in various locations of the process plants, there is no a generally accepted and verified twophase flow model that may be used to size lines for such conditions. An obvious example is condensate water return lines. The API method used in this study is based on the homogeneous equilibrium flow assumption, that is, equal velocity and equal temperature in both liquid and vapor phases. Moreover, DIERS method was used to verify and clarify the HEM approach to calculating the Pressure drop in twophase regimes. The objective of this study is to introduce a solution for process lines design during different flashing scenarios. Applying API method, this study can find the two-phase line Pressure drop and upstream Pressure, while, by using DIERS method, one could realize that for a specified length of pipe how much two-phase flow could pass through when the Pressure drop is just the same as that in the API model.

In this work computational fluid dynamics is used to describe the fluid flow across a randomly packed absorption tower. The CFD simulation method is employed on a packed tower that is packed with 1cm Raschig rings. Tower is 175cm in height. Air flow rate range was 1.5 to 5 m/s. The measured Pressure drops were in 1.5 to 12 Pascal per height of tower in meter. The Klerk’s approach is examined to define the influence of confining walls on Pressure drop in packed areas. It is concluded that CFD model that uses the Klerk’s definition of radial porosity distribution is a successful way for Pressure drop prediction in packed beds. Model prediction of dry Pressure drop is about 4% lower than the experimental measurements. Ergun’s Pressure drop prediction is compared with that of Reichelt’s using averaged and distributed porosity profiles. In both methods Ergun’s approach in comparison with Reichelt’s approach has %6 lesser error in dry Pressure drop prediction.

When a natural gas pipeline ruptures, the adjacent upstream and downstream automatic control valves (ACV) should close quickly to prevent leakage or explosion. The differential Pressure set point (DPS) at each valve location is the main criteria for value setting in ACV actions. If the DPS is not properly adjusted, the ACV may mistakenly close or it may not take any actions at a proper time. In this study, the effect of characteristic parameters such as pipeline operational Pressure (POP) and pipeline Pressure drop rate (ROD) due to rupture or a major leak was experimentally investigated on DPS. 25 different conditions with the double set of the mentioned typical characteristic parameters were chosen. In each condition, the differential Pressure (DP) was measured over a period of 180 s by statistically analyzing the experimental results, so 25 maximum DP values (DPSs) were obtained. The DPS rises by an increase in ROD or a decrease in POP. Because of using nitrogen gas instead of natural gas for safety reasons and the uncertainties, the DPS results can be practically applied by adding a safety factor of 15%. Finally, the diagram of DPS with respect to ROD and that of non-dimensional DPS (DOP) versus non-dimensional ROD (RTP) were provided for different POP’ s.