Hot inlets

Direct Sample passes directly from syringe to hot inlet where it vaporises. Packed column inlets Dilute samples Thermally stable Fair, some focusing required 0.1-2 100... 

Hot split Sample (usually liquid) passes from syringe into hot inlet rapid vaporisation initial oven temperature not critical small fraction allowed to column (split ratios 1 20 to 1 400) Concentrated samples Narrow 0.1-2 0.01-10... 

Hot splitless Liquid sample passes from syringe into hot inlet initial oven temperature critical (ca. 10 °C lower than b.p. of solvent) bulk of sample enters column (splitless time of 10-40 s) Dilute samples, containing heavy by-products Very broad, focusing required 0.1-2 80-95... 

This pathway is consistent with the loss of the OH and y hydrogen (n = 1) or 8 hydrogen (n = 2) the ring structure is not proved by the observations and is merely one possible structure for the product radical cation. The M - 18 peak is frequently exaggerated by thermal decomposition of higher alcohols on hot inlet surfaces. Elimination of water, together with elimination of an alkene from primary alcohols, accounts for the presence... 

The mass spectra of quinones often give rise to M -(-1 and M -(- 2 ions by addition of hydrogen and this has been considered to be due to reaction with water on the surfaces of a hot inlet system (Aplin and Pike, 1966). Similar results, which were temperature- but not pressure-dependent, have been obtained with a direct inlet system (Ukai et al., 1967 Dean and Houghton, 1968 Oliver and Rashman, 1968). The mass spectra of vinylchlorins (Budzikiewicz and Drewes, 1968) and of s-tetrazines (Yates et al., 1968) all showed M-f2 ions, whilst the strongest peaks in the mass spectrum of N-bromosuccinimide were due to succinimide (Bentley and Johnstone, 1968b). 

Here Cg is the humid heat Cpc + YCpy. In convective dryers, the left-hand side is dominated by the sensible heat of the hot inlet gas GCsiTci in contact dryers, the heat input from the jacket pin is dominant. In both cases, the largest single term on the right-hand side is the latent heat of the vapor GXYq- Other terms are normally below 10 percent. This shows why the operating line of a convective dryer on a psychrometric chart is roughly parallel to a constant-enthalpy line. 

We will also have heat flow equations similar to those for the TS-BR and TS-PFR reactors, but with the addition of a new term to account for cool/hot inlet feed mixing with hot/cool reactant inside the reactor. To find an expression for this term, consider, over a short time dt, a volume of fluid fbdt altering the reactor at temperature TE It expands to volume Syf) inside the reactor, and mixes with the remaining volume V- 5v fb dt which is at temperature T. The mixture then has a resulting temperature of. 

Syringe injection into a hot inlet system remains the most common way of sample introduction in GC analysis. It is, however, the most frequent source of error in... 

The remaining 2000 units of coldl can be matched against hotl in E6, even if the CP rule is not respected. This is because the previous match has lowered the temperature of the cold outlet corresponding to the hot inlet (located at Pinch). For this heat exchanger the heat balance is g6=100x(140-120)=150x(63.3-50)=2000. 

Upward air flow can minimize spray drying since hot inlet air is introduced under the bed away from the spray area. Evaporative cooling and solvent vaporization as the air passes through the bed reduces the drying capacity of the air in the spray zone. 

Downward air flow introduces hot inlet air near the spray zone, which may promote spray drying. 

In the Item 1 column that contains the values, the items for Hot Inlet Stream and Hot Outlet Stream are ICUST-IN and ICUST-EX, respectively, which correspond to the default utility, in this case, steam at 50 psi. To change to steam at 100 psi, right click on the appropriate cells and select Steam 100 PSI - IPE Utility from the pull-down menu that appears. Next, delete the Final Surface Area, previously computed, since it must be re-sized by Aspen IPE ... 

NPSH supplied or NIPA supplied too small] strainer dogged/temperature too hot/ inlet line clogged/inlet line diam. too small or length too long/atmospheric pressure < design. 

Fig-5 refers the BAHE-2 Gas/Liquid exchanger streams temperature trends. Most important point here hot stream (i.e. feed gas) outiet temperamre is almost constant —65degC even when hot inlet stream temperature is varying. This is mainly because 1. Cold stream-2 (i.e. side reboiler) is driven by thermosiphon hence self-adjusts the flow thorough exchanger as heat load varies. 2. Cold stream-1 (i.e. expander feed separator liquid) flow impacted due to loss of level in drum when feed gas C3+ content reduces. 

The left-hand side of Figure 6.24 shows temperature distribution on the hot and cold fluid streams on 15 different cross sections. The figure shows the hot inlet stream temperature, presented in white or 329 K, and the cold inlet stream temperature, presented in red or 301 K. At the central part of the heat exchanger, the temperature reaches uniform value, presented in orange or 315 K. The streamlines show the conductive heat flux, which is the most intensive in the middle of the heat exchanger. The right-hand side of Figure 6.24 shows the temperature distribution in hot and cold... 

With direct injection below 5 mg/kg sulfur the base line shift error due to the needle septum blank may become significant. Such error can be avoided by inserting the syringe needle into the hot inlet and allowing the needle septum blank to be titrated before injecting the sample. 

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