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Temperature liquid-separation system

A direct liquefaction technique, the SRC process involves mixing dried and finely pulverized coal with a hydrogen donor solvent, such as tetralin, to form a coal-solvent slurry. The slurry is pumped together with hydrogen into a pressurized, vertical flow reactor. The reactor temperature is about 825°F (440°C) and pressures range from 1,450 to 2,000 psi. A residence time in the reactor of about 30 minutes is required for the carbonaceous material to dissolve into solution. From the reactor, the product passes through a vapor/liquid separation system. The slurry solids remaining in the reactor are then removed and filtered. Various filtration techniques have been developed to remove solids from recoverable oil. [Pg.277]

The phase-split block can be a single flash, a series of flashes, or a combination of flash and absorption/stripping columns. Flash temperature and pressure are design variable that may be optimised to fulfil a separation objective, as sharp gas/liquid split or recovery of some components. For water-driven condensers the recommended condensation temperature is of about 35 °C. Vapour components can be condensed and sent to the liquid separation system. The supercritical components carried in the liquid phase can be recovered in a stabiliser column (see later in this section). Further, these can be sent to the gas separation system, used as fuel, or purged. [Pg.257]

The synthesis of the liquid separation system for the HDA process has been discussed in Chapter 7. The flowsheet consists of three columns C-1 (stabiliser), C-2 (production), and (C-3) recycle. For the same operation point discussed before Table 17.8 presents some characteristics of the three columns. Note that a cooler (duty 730 kW) should be inserted before the column C-2 to bring the feed at its bubble point. The design is valid for a benzene purity of 99.8 %, as well as for a loss of toluene in Heavies of about 0.4%, imposed by the limitation of reboiler temperature in the recycle column below 200 °C. [Pg.649]

FI gas-liquid separation systems may be classified according to the chemical processes involved. In most cases the analyte is transformed into a volatile species by means of a suitable acid-base chemical reaction before the separation such as for the release of carbon dioxide, sulphur dioxide, hydrogen cyanide, hydrogen sulfide. Sometimes the analyte is sufficiently volatile to be separated from the liquid phase under elevated temperatures without further reaction. Among these are ethanol, ozone, and chlorine dioxide. [Pg.130]

Highly pure / -hexane can be produced by adsorption on molecular sieves (qv) (see Adsorption, liquid separation) (43). The pores admit normal paraffins but exclude isoparaffins, cycloparaffins, and aromatics. The normal paraffins are recovered by changing the temperature and/or pressure of the system or by elution with a Hquid that can be easily separated from / -hexane by distillation. Other than ben2ene, commercial hexanes also may contain small concentrations of olefins (qv) and compounds of sulfur, oxygen, and chlorine. These compounds caimot be tolerated in some chemical and solvent appHcations. In such cases, the commercial hexanes must be purified by hydrogenation. [Pg.405]

Second, Schneider s article reviews recent work (notably by Rowlinson, Kohn and co-workers) on phase relations in binary liquid systems where one of the components is much more volatile than the other (D1, D2, E3, M8, R9). Such systems may have lower critical solution temperatures for these systems, an increase in temperature (and, indirectly, pressure) causes precipitation of the heavy component, thereby providing a possible separation technique, e.g., for the fractionation of polymers. [Pg.190]

Some typical applications in SFE of polymer/additive analysis are illustrated below. Hunt et al. [333] found that supercritical extraction of DIOP and Topanol CA from ground PVC increased with temperature up to 90 °C at 45 MPa, then levelled off, presumably as solubility became the limiting factor. The extraction of DOP and DBP plasticisers from PVC by scC02 at 52 MPa increased from 50 to 80 °C, when extraction was almost complete in 25 min [336]. At 70 °C the amount extracted increased from 79 to 95 % for pressures from 22 to 60 MPa. SFE has the potential to shorten extraction times for traces (<20ppm) of additives (DBP and DOP) in flexible PVC formulations with similar or even better extraction efficiencies compared with traditional LSE techniques [384]. Marin et al. [336] have used off-line SFE-GC to determine the detection limits for DBP and DOP in flexible PVC. The method developed was compared with Soxhlet liquid extraction. At such low additive concentrations a maximum efficiency in the extractive process and an adequate separative system are needed to avoid interferences with other components that are present at high concentrations in the PVC formulations, such as DINP. Results obtained... [Pg.96]

The intermediate storage between the reaction and separation system can also help dampen out variations in composition, temperature and flowrate between the two sections (for gases and non-viscous liquids, but not solids). Variations in the outlet properties from the storage are reduced compared with variations in the inlet properties. [Pg.288]

Others have examined the necessary parameters that should be optimized to make the two-dimensional separation operate within the context of the columns that are chosen for the unique separation applications that are being developed. This is true for most of the applications shown in this book. However, one of the common themes here is that it is often necessary to slow down the first-dimension separation system in a 2DLC system. If one does not slow down the first dimension, another approach is to speed up the second dimension so that the whole analysis is not gated by the time of the second dimension. Recently, this has been the motivation behind the very fast second-dimension systems, such as Carr and coworker s fast gradient reversed-phase liquid chromatography (RPLC) second dimension systems, which operate at elevated temperatures (Stoll et al., 2006, 2007). Having a fast second dimension makes CE an attractive technique, especially with fast gating methods, which are discussed in Chapter 5. However, these are specialized for specific applications and may require method development techniques specific to CE. [Pg.130]

Whereas in Gas Recycle the product must be removed at the same temperature and pressure at which it is formed, in Liquid Recycle the separation of product (and byproducts) from catalyst is independent of the conditions under which the products were formed. This added degree of control brings a variety of benefits. Since large gas flows are no longer required in the reactor, the liquid expansion due to gassing is reduced and more catalyst can be contained in a specific reaction vessel. Reactor temperature and reactant concentrations can be tuned for optimum catalyst performance. The conditions in the separation system can likewise be tuned for optimum performance. In particular, more severe conditions will permit better control over the concentration of heavies in the catalyst solution. [Pg.14]

A separate preparation of azides is not always necessary. Scheme 183 illustrates a case where azides are generated in situ from the corresponding halides. The reactions are carried out in ionic liquid-water system. Triazole 1117 is obtained in 94% yield from a reaction carried out at room temperature for 4h. Butyl derivative 1118 is obtained in 90% yield under similar conditions <2006TL1545>. [Pg.125]

Since members of a homologous series have incremental boiling point differences and if the amount of any homolog in the moving gas phase is related to vapor pressure at the temperature of the experiment, plots of log k vs. carbon number should also be a straight line. (The enthalpy of vaporization increases monotonically with carbon number.) This in fact is observed in gas-liquid equilibrium separation systems. It is the basis of retention index systems pioneered by Kovats for qualitative identification. [Pg.415]

If gas-liquid and gas-solid separations are dependent on the saturation vapor pressure of the chemical component undergoing equilibration (a) What is the expected effect when the temperature of the system is raised (b) If the system is a gas-liquid system sketch what a plot of log VT vs. 1 IT would look like including when the T is below the freezing point of the stationary phase, (c) Why might it be better to sample the vapor phase above a solution as a sample to determine trace materials in the solution ... [Pg.417]

In this theory the adsorbed layers are considered to be contained in an adsorption space above the adsorbent surface. The space is composed of equipotential contours, the separation of the contours corresponding to a certain adsorbed volume, as shown in Figure 17.7. The theory was postulated in 1914 by Polanyi(18), who regarded the potential of a point in adsorption space as a measure of the work carried out by surface forces in bringing one mole of adsorbate to that point from infinity, or a point at such a distance from the surface that those forces exert no attraction. The work carried out depends on the phases involved. Polanyi considered three possibilities (a) that the temperature of the system was well below the critical temperature of the adsorbate and the adsorbed phase could be regarded as liquid, (b) that the temperature was just below the critical temperature and the adsorbed phase was a mixture of vapour and liquid, (c) that the temperature was above the critical temperature and the adsorbed phase was a gas. Only the first possibility, the simplest and most common, is considered here. [Pg.991]

As indicated in Chapter 2, liquid drops falling through gases have such extreme values of y and k that they must be treated separately from bubbles and drops in liquids. Few systems have been investigated aside from water drops in air, discussed above, and what data are available for other systems (FI, G5, L5, V2) show wide scatter. Rarely have gases other than air been used, and some data for these cases [e.g. (L5, N2)] cannot be interpreted easily because of evaporation and combustion effects. Results for drops in air at other than room temperature (S8) differ so radically from results of other workers that they cannot be used with confidence. [Pg.178]

Crude oil vapor pressure is the specification which most influences the design of oil-gas separation systems. For offshore tanker loading, the oil may be limited to a vapor pressure In the range of 8 to U pounds KVP (Reid Vapor Pressure). RVP refers to a standard method of vapor pressure testing utilizing a specific test cylinder assembly. and determined at a temperature of 100°F. RVP is (not Identical with TVP (true vapor pressure), which is the actual vapor pressure exerted by a liquid in equilibrium with a vapor at any given temperature. [Pg.77]

Gas specifications will be inqportant only if the gas is to be delivered to a gas pipeline system. If the gas is to be injected in the producing field the only usual critical requirement is to dehydrate the gas adequately to prevent hydrate formation anywhere in the system. The gas pipeline specification which most Influences the design of oil-gas separation systems is the hydrocarbon dewpoint limitation. This is usually expressed as a maximum dewpoint temperature at a specified pressure. For onshore gas pipelines in the USA end Europe this specification may be in the range of 32°F (0°C) at 1000 paia (68 atmospheres), which is adequate to prevent condensation of liquids in the pipelines in the normal range of onshore pipeline operating pressures from 900 to 1000 psl. In the USA this specification is seldom iiqposcd on producers and is controlled with pipeline facilities. [Pg.77]

The first step is to use a separate cooling and separation system on the vapor streams from each stage and the recompression gases, as in Figure 4. This reduces recycle loads, because the recompressed vapors are not subjected to the absorber effect of the crude oil streams at each stage. It still is not possible to control the temperature D, but the temperature 1 can be controlled, as well as the pressure D and 1, and the crude oil product is a combination of the liquid streams from separations D and 1. If the inlet wells , re am is hot, which Is frequently expected with the high well flow rates sometimes obtained in the North Sea, this system may be much more selective because different temperature levels can be maintained in 1-4 as compared to A-D. It usually is poesible to establish a pressure level for D and 1 which will allow control of the oil vapor pressure. Recycle loads nwy still be a problem with this process, but not as much as in the previous one. [Pg.82]


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