Designing 3D Membrane Modules for Gas Separation Based on Hollow Fibers from Poly(4-methyl-1-pentene)

Designing hollow fiber (HF) membrane modules occupies one of the key positions in the development of efficient membrane processes for various purposes. In developing HF membrane modules, it is very important to have a uniform HF distribution and flow mixing in the shell side to significantly improve mass transfer and efficiency. This work suggests the application of different textile 3D HF structures (braided hoses and woven tape fabrics). The 3D structures consist of melt-spun, dense HFs based on poly(4-methyl-1-pentene) (PMP). Since the textile processing of HFs can damage the wall of the fiber or close the fiber bore, the membrane properties of the obtained structures are tested with a CO2/CH4 mixture in the temperature range of 0 to 40 °C. It is shown that HFs within the textile structure keep the same transport and separation characteristics compared to initial HFs. The mechanical properties of the PMP-based HFs allow their use in typical textile processes for the production of various membrane structures, even at a larger scale. PMP-based membranes can find application in separation processes, where other polymeric membranes are not stable. For example, they can be used for the separation of hydrocarbons or gas mixtures with volatile organic compounds.

Comparison of Heat Transfer rates for Water and Ethylene Glycol mixtures for Diesel engine exhaust gas heat recovery using Shell and Tube Heat Exchanger.

Most of the researchers have claimed that high compression engines (diesel engines) are performing slightly above of 1/3rd of their potential and remaining heat energy is wasted in the form of exhaust gas. Efforts are going on to improve the design of these engines and investigations are being carried out to recover this waste energy from exhaust gases and utilize for different applications.In the present work, initially water is used as a heat exchange medium for three different loads on diesel engine viz., 50%, 60% and 70%, which extracts heat energy to evaluate the exhaust heat attainable from exhaust gases of the engine. The exhaust gas is passed through the tube side of the heat exchanger which is obtained from an exhaust manifold of a four stroke single cylinder diesel engine. Water is passed through the shell side of the shell and tube heat exchanger. Later this work is repeated for two different cooling medium i.e. water-ethylene glycol mixtures with 25% and 50%. The results are compared for 60% engine load conditions. The counter flow type heat exchanger arrangement is considered for the analysis. The temperatures were recorded for hot gases and cold medium at inlet and outlet points of the shell side and tube side flow. Heat calculations are carried out for each combination and detailed in the result–discussion and conclusion chapter. The objective of this work is to assess the exhaust gas heat recovery capacity using the ethylene glycol-water mixture and come out with a mixture for higher heat recovery capacity. This work is undertaken with segmental baffle heat exchanger of zero degree inclination. Also the work is repeated for inclined baffle heat exchangers of 10-degree and 20-degree baffle inclination to assess the effectiveness of liquid in recovering the heat from exhaust gases. It is observed that the water and Ethylene glycol mixtures have performed satisfactorily in all three baffle setups showing only 1.5% - 2.0% less heat recovery when compared with only water.

Numerical Simulation of Heat Exchanger for Analyzing the Performance of Parallel and Counter Flow

Heat exchangers are almost used in every industry. Among them, shell and tube heat exchangers are covering around 32% of the total heat exchanger. Numerical simulation of the Computational models is playing an important role for the prototypes including the Heat Exchanger Models for the improvement in modeling. In this study, the CFD analysis of parallel and counter flow shell and tube heat exchanger was performed. Following project, looked into the several aspects and these are the temperature, velocity, and pressure drop and turbulence kinetic energy along with the heat exchanger length. Hot water was placed in tube side and cold water was placed in shell side of the heat exchanger. Shell side cold temperature was increasing along the heat exchanger length. On the other side, tube side hot water temperature was decreasing along the tube length. This effect was more significance in counter flow rather than the parallel flow. Velocity was more fluctuating in the shell side due to presence of the baffles. Also following the same reason, pressure drop was higher in the shell side cold water rather than the tube side hot water. To measure the turbulence effect, turbulence kinetic energy was determined. Turbulence was decreasing first part of the shell and tube heat exchanger. But, it was increasing along through the rest part heat exchanger. All these observations and the outcomes are evaluated and then further analyzed

ANALISIS EFEKTIVITAS PENUKAR KALOR PIPA HELIKAL DESTILASI MINYAK ATSIRI KAYU PUTIH

The Eucalyptus plant is one of the essential oil-producing plants. Eucalyptus oil processing generally uses the distillation method. Traditionally used eucalyptus oil distillation uses a straight pipe condenser. The weakness of the straight pipe condenser is that the temperature of the condensate that comes out is still very high, this shows that the effectiveness of the straight pipe condenser is not optimal. To optimize the effectiveness of the distillation system condenser, a condenser with a helical pipe type condenser is designed in the essential oil distillation system. This study will vary the ratio of the pitch distance to the diameter of the condenser pipe, which aims to obtain an effective helical coil pitch ratio to optimize the effectiveness of the helical pipe condenser. This study uses the simulation method on COMSOL Multiphysics 5.4. The pitch ratio variant used is 2.1; 2.62; 3.15; 3.67; 4.2. The parameters that are constant in this study are the inlet fluid temperature on the tube side 373 K, the inlet fluid temperature on the shell side 288 K, the fluid inlet velocity on the tube side 0.2 m/s, and the fluid inlet velocity on the shell side 1 m/s. The results of the simulation by varying the pitch ratio show that the effectiveness increases as the pitch ratio value decreases, where the highest effectiveness is shown at pitch ratio of 2.1 which 75.9% and the lowest effectiveness is shown to pitch ratio of 4.2 which 70.7%.

The Unified Theory of Tubesheet Design - Part I: Theoretical Foundation

The unified theory of tubesheet (TS) design for fixed TS heat exchangers (HEX), floating head and U-tube HEX is presented by removing the mid-plane symmetry (MPS) assumption, which assumes a geometric and loading plane of symmetry at the midway between the two TSs so that only half of the HEX or one TS need be considered. All common types of HEXs, with arbitrary combinations of TS configurations, and with arbitrary geometric, material properties and temperature for each component are considered by the unified theory. The effects of unperforated annual plate, TS flange, gravitational (e.g. dead-weight of tubes, catalyst inside tubes, shell side fluid and tube side fluid) and fluid flow pressure loss, bending stiffness of the tubes, TS in-plane stretch, pressure in TS perforations, differential temperature growth in TS radial direction as well as the temperature gradient in TS thickness direction are also evaluated by the unified theory. Theoretical analysis shows that existing theories of TS design can be derived from the unified theory as special deductions. Structure comparison shows the unified theory covers a wide range of applicable HEX configuration well beyond existing theories. Numerical Comparison indicates that predictions given by the unified theory agree well with finite element analysis (FEA), while ASME results are not accurate or not correct.