Inlet gas stream

Dry inlet gas that has been dehydrated by molecular sieves (qv) or alumina beds to less than 0.1 ppm water is spHt into two streams by a three-way control valve. Approximately 60% of the inlet gas is cooled by heat exchange with the low pressure residue gas from the demethanizer and by external refrigeration. The remainder of the inlet gas is cooled by heat exchange with the demethanized bottoms product, the reboiler, and the side heater. A significant amount of low level refrigera tion from the demethanizer Hquids and the cold residue gas stream is recovered in the inlet gas stream. 

If objective is to recover adsorbed components (free of water vapor), inlet gas stream should be dried before molecular sieve adsorption process occurs (water adsorption on mol sieves is particularly strong because of polarity of surface). 

In terms of an economic determination, gas temperature adjustment is often the most important cost factor in determining whether to use a biofilter or a more conventional system. If the process gas stream is at an extremely high temperature (-i-I00° C), the cost of cooling the inlet gas stream might favor more conventional methods for odor control such as thermal oxidation. 

Figure 5-1 shows a typical LTX process. The inlet gas stream is choked at the well to 2,000 to 3,000 psi or until the temperature declines to approximately 120°F, which is well above the hydrate formation temperature. The inlet stream next enters a coil in the bottom of the low temperature separator. The stream is then cooled to just above the hydrate formation temperature with the outlet gas coming off the low temperature separator. This assures the lowest possible temperature for the inlet stream when it enters the vessel after the choke. This choke is mounted in the vessel itself. When the pressure drop is taken, the temperature will... 

The reaction requires the presence of slightly alkaline water and a temperature below 11 O F. If the gas does not contain sufficient water vapor, water may need to be injected into the inlet gas stream. Additionally, bed alkalinity should be checked daily. A pH level of 8-10 should be maintained through the injection of caustic soda with the water. 

For each component in the inlet gas stream, there will be a section of bed depth, from top to bottom, where the desiccant is saturated with that component and where the desiccant below is just starting to adsorb that component. The depth of bed from saturation to initial adsorption is known as the mass transfer zone. This is simply a zone or section of the bed where a component is transferring its mass from the gas stream to the surface of the desiccant. 

Apparatus and Procedure. The kinetic studies of the catalysts were carried out by means of the transient response method (7) and the apparatus and the procedure were the same as had been used previously (8). A flow system was employed in all the experiments and the total flow rate of the gas stream was always kept constant at 160 ml STP/min. In applying the transient response method, the concentration of a component in the inlet gas stream was changed stepwise by using helium as a balancing gas. A Pyrex glass tube microreactor having 5 mm i.d. was used in a differential mode, i.e. in no case the conversion of N2O exceeded 7 X. The reactor was immersed in a fluidized bed of sand and the reaction temperature was controlled within + 1°C. 

The response of the component Y in the outlet gas mixture to a step change in the concentration of X in the inlet gas stream is designated as X-Y response. 

The following symbols will be used when X is increased, X(inc.,)-Y when X is decreased, X(dec.,)-Y when X is increased from nil, X(inc.,0)-Y when decreased to nil X(dec.,0)-Y when X is pulsed in the inlet gas stream, X(pulse)-Y response when the temperature of the catalyst bed is raised linearly with respect to the elapsed time, T(linear)-Y response. 

Choosing an increment such that the exit liquor stream and inlet gas streams have compositions X = 0.005 and Y, a mass balance taking 1 m2 as a basis gives ... 

Repeat the reactor simulation, but with an inlet gas stream consisting of 0.33 Torr of SiH4,10 Torr of H2, and 189.7 Torr of He. What is the maximum number density of Si in this simulation Give a qualitative, chemical explanation for the change from the pure He calculation in task 1. 

The purity of the well stream is an important factor in the design of LNG plants. As the Snohvit gas contains 5-8 % carbon dioxide C02 will be captured from the inlet gas stream by a MDEA process and returned via a separate line for off-shore re-ini ection beneath the seabed close to the wells [17,18]. 

Note that the heat exchangers are partially imbedded in the insulation thickness. The top portion of each heat exchanger is exposed to the hot zone radiant environment, which helps to insure that the inlet gas streams achieve the desired electrolyser operating temperature prior to entering the stacks. The temperature at the bottom of each heat exchanger will be close to the inlet stream temperature, minimising the thermal load on the hot zone base plate in the vicinity of the tubing penetrations. 

In all cases, the efficiency of removal using a control device is given by the collection efficiency, equal to the ratio amount collected in the device to the amount in the inlet gas stream. Another common measure of efficiency is the penetration, which is 1 minus the collection efficiency. The decontamination factor is the reciprocal value of the penetration. Modern gascleaning machinery aims for very high collection efficiencies exceeding 99%, at least over a given particle size range. 

FIGURE 4 Schematic diagram of a typical large-scale highspeed vertical rotating-disk MOCVD reactor chamber including a simplified view of gas flow in a vertical RDR. The inlet gas stream contains the precursor flows and the main carrier gas flow. Typically, the Column V and Column III sources are kept separate until a few inches above the heated susceptor. 

The rest of the parameters which define the behavior of the cell for each set of oj rating conditions include the cathode inlet gas stream composition, flow rate, and total pressure the degree of humidification of the inlet as stream and the temperature of the cell. Some important assumptions made in choosing these parameters and in... 

Equations 47-49 describe variations of parameters along the y coordinate of the catalyst layer (y = z/lc 1), where z is the catalyst layer thickness coordinate, y = 0 specifies the catalyst layer/gas interface, and y = 1 specifies the catalyst layer/ionomeric membrane interface (see Fig. 44), in which Rc (= /Ci/cr) is the protonic resistance through a unit cross-sectional area of the catalyst layer and 7d (=nFDC /lc ) is a characteristic diffusion-controlled current density in the catalyst layer. The thickness of the catalyst layer disappears from the equations by introducing Rc, ax, and I ). The experimental variables considered include the overpotential 1], the current density /, and the oxygen concentration C, when pox = 1 atm at the catalyst layer/gas interface. The O2 partial pressure, pox, at the catalyst layer/backing layer interface is determined, in turn, by the cathode inlet gas stream composition and stoichiometric flow rate and by the backing layer (GDL) transport characteristics. 

In an open flame configuration, the homogeneous reaction must occur to some extent because the gas stream passes through an open flame at a high temperature. Thus, the downstream catalytic reaction may involve different reactant species than if the gas stream had not passed through an open flame, making study of the catalytic oxidation itself difficult. An additional complication is the possibility of chemical reaction between the fuel used for the flame and the VOC in the inlet gas stream, which could result in a variety of products. 

Phase equilibrium. To get the minimum liquid flow rate, we are assuming the inlet gas stream is in equilibrium with the liquid outlet stream this means the ammonia fractions in the two streams are related by a K-factor,... 

The Compressor operation is used to increase the pressure of an inlet gas stream. Depending on the information specified, the Compressor calculates ether a stream property (pressure or temperature) or compression efficiency. 

The Expander operation is used to decrease the pressure of a high pressure inlet gas stream to produce an outlet stream with low pressure and high velocity. An expansion process involves converting the internal energy of the gas to kinetic energy and finally to shaft work. The Expander calculates either a stream property or an expansion efficiency. 

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