Liquids injected under pressure

Liquids injected under pressure into the soil, e.g. anhydrous and aqueous ammonia. 

Deep-well disposal of liquids consists of their injection under pressure to underground strata isolated by impermeable rock strata from aquifers. Early experience with this method was gained in the petroleum industry where disposal is required of large quantities of saline wastewater coproduced with crude oil. The method was later extended to the chemical industry for the disposal of brines, acids, heavy metal solutions, organic liquids, and other Uquids. 

If a vapor sample is to be injected using a gas sample valve, a representative portion of the liquid butylenes must be taken and vaporized into a suitable container. As a suggestion, a small, 5 or 10 mL aliquot of liquid butylenes under pressure in a valved, 5 or 10-mL sample cylind can be expanded into a laiger container as a vapor. Then this resultant vapor would be injected into the chromatograph. 

With PBAs the compressed gases often used are nitrogen or carbon dioxide. These gases are injected into a plastic melt in the screw barrel under pressure (higher than the melt pressure) and form a cellular structure when the melt is released to atmospheric pressure or low pressure. The volatile liquids are usually aliphatic hydrocarbons, which may be halogenated, and include materials such as carbon dioxide, pentane, hexane, methyl chloride, etc. Polychlorofluoro-carbons were formerly used but they have now been phased out due to environment problems. 

Pachuca tank The simplest and most inexpensive device for agitating the pulp. Agitation is achieved by the injection of air under pressure into the bottom of a tall tank. The rising gas draws the surrounding liquid with it to the surface... 

Ammonia is a gas that can be readily converted to liquid form and stored as such under pressure. For fertilization, it can be injected directly into the soil from capsule-shaped tanks. I grew up in the Midwest and still spend some time there for family reasons. An ammoiua tank being towed through farmland behind... 

A gaseous mobile phase flows under pressure through a heated tube either coated with a liquid stationary phase or packed with liquid stationary phase coated onto a solid support. The analyte is loaded onto the head of the column via a heated injection port where it evaporates. It then condenses at the head of the column, which is at a lower temperature. The oven temperature is then either held constant or programmed to rise gradually. Once on the column separation of a mixture occurs according to the relative lengths of time spent by its components in the stationary phase. Monitoring of the column effluent can be carried out with a variety of detectors. 

At this stage, one has to take into account the volume compressibility of the material, since upon feed-up the hold-on time of material under pressure is determined by compressibility and slow viscous flow. If the pressure of injection PQ is sufficiently high, then at this stage a liquid may be considered to be Newtonian with viscosity q ,. Keeping this in mind, we may state that the calculation given below will be applicable to various plastisols (of types I and II) with the only difference that for plastisol I q = const, while for plastisol II q = q. For the sake of simplicity, the analysis will be performed for the case of a flat mould filled through a slit runner (Fig. 10 a). 

Sample introduction is a major hardware problem for SFC. The sample solvent composition and the injection pressure and temperature can all affect sample introduction. The high solute diffusion and lower viscosity which favor supercritical fluids over liquid mobile phases can cause problems in injection. Back-diffusion can occur, causing broad solvent peaks and poor solute peak shape. There can also be a complex phase behavior as well as a solubility phenomenon taking place due to the fact that one may have combinations of supercritical fluid (neat or mixed with sample solvent), a subcritical liquified gas, sample solvents, and solute present simultaneously in the injector and column head [2]. All of these can contribute individually to reproducibility problems in SFC. Both dynamic and timed split modes are used for sample introduction in capillary SFC. Dynamic split injectors have a microvalve and splitter assembly. The amount of injection is based on the size of a fused silica restrictor. In the timed split mode, the SFC column is directly connected to the injection valve. Highspeed pneumatics and electronics are used along with a standard injection valve and actuator. Rapid actuation of the valve from the load to the inject position and back occurs in milliseconds. In this mode, one can program the time of injection on a computer and thus control the amount of injection. In packed-column SFC, an injector similar to HPLC is used and whole loop is injected on the column. The valve is switched either manually or automatically through a remote injector port. The injection is done under pressure. 

In the empty-cell process, the preservative liquid is forced under pressure into the wood, containing either its normal air content (Lowry process) or an excess of air, by first subjecting the wood to air pressure before applying the preservative under pressure (Rueping process). In the former case, the preservative is put in the cylinder containing the wood at atmospheric pressure, and, in the latter case, under air pressure of 25-100 psi. After the wood has been subjected to the hot preservative (about 190-200°F) underpressure (100-200 psi in the Lowry process and 150-200 psi in the Rueping process) and the pressure has been released, the back pressure of the compressed air in the wood forces out the free liquid from the wood. As much as 20-60 percent of the injected preservative may be recovered, yet good depth of penetration of the preservative is achieved. 

Melting (plasticating) the plastic is accomplished in a plasticator (screw in barrel as described in Chapter 3). This melt is forced into a clamped mold cavity. The liquid, molten plastic from the injection cylinder of the injection machine is transferred through various flow channels into the cavities of a mold where it is finally shaped into the desired object by the confines of the mold cavity. What makes this apparently simple operation complex is the limitations of the hydraulic or electrical circuitry used in the actuation of the injection plunger and the complicated flow paths involved in the filling of the mold (Chapter 17). Finally opening the mold to eject the plastic after keeping the material confined under pressure as the heat in the melt is removed to solidify the plastic into the shape desired. 

Spin casting can use plastic molds, such as silicone, to produce close tolerance, highly cost effective, limited production in a variety of materials. The process uses easily adjustable centrifugal force to inject liquid thermoset plastics into a circular disc-shaped elastomeric mold under pressure, completely and rapidly filling the mold cavities. 

Sulfur dioxide and sulfites have long been used as preservatives, serving both as antimicrobial substance and as antioxidant. Their use as preservatives in wine dates back to Roman times. Sulfur dioxide is a gas that can be used in compressed form in cylinders. It is liquid under pressure of 3.4 atm and can be injected directly in liquids. It can also be used to prepare solutions in ice cold water. It dissolves to form sulfurous acid. Instead of sulfur dioxide solutions, a number of sulfites can be used (Table 11-2) because, when dissolved in water, they all yield active S02. 

Injection of liquid tracer (KC1 at 3M) under pressure is achieved by a system of three electrovalves (3) and allows injection of the tracer with a Dirac type impulse. The tracer concentration is monitored in time using a conductimeter and a recorder. In order to... 

In this connection, a series of steady state displacement tests were conducted in a 170-200 mesh bead pack with a porosity of 0.4 and an absolute permeability of 7000 md. The experimental apparatus is shown in Figure 7. Two types of gas injection were employed - constant pressure injection and constant rate injection air was used in the former, nitrogen in the latter. The liquid phase was water plus surfactant (0.25% by volume Amphosal CA, Stepan Chemical Company) and was always injected under constant... 

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