Gas effluents

Practically all of the H2S and NH3 is stripped from the water, and, with a small amount of phenols remaining, the gas effluent is sent to the Claus unit. 

The BASF process uses /V-methy1pyrro1idinone as the solvent to purify acetylene in the cracked gas effluent. Alow pressure prescmbbing is used to remove naphthalenes and higher acetylenes. The cracked gas is then compressed to 1 MPa (10 atm) and fed to the main absorption tower for acetylene removal. Light gases are removed from the top of this tower. 

Sulfonation Plant Operations and Gas Effluent. Standards governing U.S. sulfonation plant gas effluents differ depending on whether or not the plant is equipped with a H2SO4 scmbbing system for adsorption of SO gas (see Fig. 3). The installation of the SO adsorber system qualifies the plant as a sulfuric production plant which has stringent regulations. Limitations and typical effluent from the sulfonation system are as follows ... 

A removal efficiency of 95% is attainable with high inlet gas concentrations. However, the minimum concentration of organic compounds obtained in the outlet gas effluent is equal to the saturation concentration at the operation temperature. Chilled water, brine, refrigerant propylene, and liquid nitrogen can be used as coolants. 

The non-intrusive manipulation of carrier gas effluent between two columns clearly has significant advantages in two-dimensional GC. In addition, a pressure-driven switch between the columns introduces no extra band broadening to an eluting peak. 

As an illustration, let us take a look at a bioreactor (Fig. 1.1). To find out if the bioreactor is operating properly, we monitor variables such as temperature, pH, dissolved oxygen, liquid level, feed flow rate, and the rotation speed of the impeller. In some operations, we may also measure the biomass and the concentration of a specific chemical component in the liquid or the composition of the gas effluent. In addition, we may need to monitor the foam head and make sure it does not become too high. 

Chlor-alkali cell gas effluent, gas purification, l 618t Chlor-alkali electrolytic process, 13 809 Chlor-alkali processes, 13 775... 

Sulfonation equipment, 23 515 Sulfonation operations, industrial changes affecting, 23 515-516 Sulfonation plant gas effluents, 23 552 Sulfonation plants, operations of, 23 552 Sulfonation polymer, derivation by, 13 546 Sulfonation processes... 

Figure 1-14 shows a simplified layout for an SOFC-based APU. The air for reformer operation and cathode requirements is compressed in a single compressor and then split between the unit operations. The external water supply shown in figure 1-14 will most likely not be needed the anode recycle stream provides water. Unreacted anode tail gas is recuperated in a tail gas burner. Additional energy is available in a SOFC system from enthalpy recovery from tail gas effluent streams that are typically 400-600°C. Current thinking is that reformers for transportation fuel based SOFC APUs will be of the exothermic type (i.e. partial oxidation or autothermal reforming), as no viable steam reformers are available for such fuels. 

FIG. 24-59 Characteristic curves for boiler thermal efficiency as a function of flue gas effluent temperature and flue gas water dew points. Based on the LHV of a fuel, and stoichiometric reaction, 100 percent efficiency would be achieved if sufficient combustion heat were recovered and removed, so that the temperature of the effluent flue gas was reduced to 25°C. For a flue gas with a 55°C dew point, recovering additional heat via condensation by cooling from 175 to 35°C (as shown) would increase the overall efficiency by more than 13 percent. Courtesy Combustion b- Energy Systems, Ltd. www.condexenergy.com.)... 

The technology involves raising the temperature of the contaminated equipment or material to 500°F for a specihed period of time. The gas effluent from the material is treated in an afterburner system to destroy all volatilized contaminants. The method is designed to eliminate stockpiled waste that would otherwise require disposal as a hazardous material. The HGD system can be built in a permanent position for use at a single location, or it can be built and used as a mobile unit. 

S02/Vent Streams Hg/Chlor-Alkali Cell Gas Effluent... 

In the biosphere, vanadium can be considered to be of two forms, one of which is highly mobile, whereas the other is a virtually immobile form. These are closely connected to the oxidation state of vanadium, where the mobile chemically reactive form conforms more or less, but certainly not exclusively, to the V(V) oxidation state. This is the state that vanadium will predominantly have in gas effluents in ash from oil, coal, and gas burners in some minerals and in surface water. Vana-dium(IV) complexes of the types found in minerals will often be relatively immobile but, if subjected to an oxidative environment, can enter the mobile phase in the V(V) oxidation state. Sequestered forms of vanadium can be transported by mechanical processes such as by movements of suspended materials in creeks and rivers, where translocation from terrestrial to lake or marine environments accounts for a high percentage of the movement of vanadium. This procedure does not release the vanadium into the environment in the sense that release from the substrate does rather, the vanadium is simply redeposited as the sediments settle. However, because of the high surface area of the suspended materials, vanadium can efficiently be removed from the suspended material by chemical reactions and enter into the environment as active species by this process. 

In what follows, we begin by introducing two examples of process systems with recycle and purge. First, we analyze the case of a reactor with gas effluent connected via a gas recycle stream to a condenser, and a purge stream used to remove the light impurity present in the feed. In the second case, the products of a liquid-phase reactor are separated by a distillation column. The bottoms of the column are recycled to the reactor, and the trace heavy impurity present in the feed stream is removed via a liquid purge stream. We show that, in both cases, the dynamics of the system is modeled by a system of stiff ODEs that can, potentially, exhibit a two-time-scale behavior. 

Lodding, W. Gas Effluent Analysis. New York Marcel Dekker, Inc. 1967. 

The problems of handling a liquid waste effluent are considerably more complex than those of handling a waste gas effluent. The waste liquid may contain dissolved gases or dissolved solids, or it may be a slurry in either... 

The gas and liquid are at the same temperature inside the reactor. The gas effluent is saturated with vapor of species B, and passes through an ideal condenser. The condensate is returned continously to the reactor. 

Lamparski LL, Nestrick TJ (1989), Chemosphere 19 1165-1177.. .Analytical methodology of the Dow Chemical Company for the determination of selected dibenzo-p-dioxins and dibenzofurans in stack gas effluent matrices, Part 1 ... 

In practice, the reduction temperature is raised stepwise by using the exothermic heat of ammonia formation. The progress of the reduction is controlled according to the catalyst temperature and the water concentration by adjustment of the synthesis gas flow. As a rough guideline, the water content of the gas effluent from the catalyst should not exceed 2-3 g/m3 (STP). Under these conditions, depending on its size and operating pressure, a synthesis converter with a fresh load of oxidic catalyst attains its full production capacity in 4-10 d. 

The solids produced in water softening plants, if not put to use, pose a disposal problem. Conceptually, because of their basic nature, they can be used in absorption towers that use alkaline solutions to scrub acidic gas effluents. These solids, as far as the lime-soda process is concerned, come from the solids produced in the removal of (1) the carbonate hardness and (2) the noncarbonate hardness. 

Exhaust Gas Treatment. The gas effluent must be treated to comply with environmental regulations. The exhaust gas from the reactor contains traces of organic matter and unreacted SO3 and SO2 gases. The first two impurities are removed by... 

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