Gases vaporization

Oxidation Step. A review of mechanistic studies of partial oxidation of propylene has appeared (58). The oxidation process flow sheet (Fig. 2) shows equipment and typical operating conditions. The reactors are of the fixed-bed shell-and-tube type (about 3—5 mlong and 2.5 cm in diameter) with a molten salt coolant on the shell side. The tubes are packed with catalyst, a small amount of inert material at the top serving as a preheater section for the feed gases. Vaporized propylene is mixed with steam and ak and fed to the first-stage reactor. The feed composition is typically 5—7% propylene, 10—30%... 

The degree to which inhaled gases, vapors, and particulates are absorbed, and hence their potential to produce systemic toxicity, depends on their solubihty in tissue fluids, any metaboHsm by lung tissue, diffusion rates, and equiUbrium state. 

Thermal treatment is used to destroy, break down, or aid in the desorption of contaminants in gases, vapors, Hquids, sludges, and soHds. There are a variety of thermal processes that destroy contaminants, most of which are classified as incineration. Incineration HteraHy means to become ash (from Medieval Latin, incinerare in or into ashes). With respect to the incineration of hazardous wastes regulated in the United States, however, there is a strict legal definition of what constitutes an incinerator. The Resource Conservation and Recovery Act (RCRA) definition of incinerator at 40 CFR 260.10 is... 

In industrial air-conditioning systems, harmful environmental gases, vapors, dusts, and fumes are often encountered. These contaminants can be controlled by exhaust systems at the source, by dilution ventilation, or by a combination of the two methods. When exhaust... 

Sections II and III describe the types and form of gases, vapors, and particles in the atmosphere. Definitions of terms are offered at the beginning... 

A 3 Gaseous (gases, vapors, airborne particulates) W = Wastewater (aqueous waste) B11 Biological Treatment - Aerobic... 

Permeation rates are dependent on the ehemieal makeup of the eontamination. This ineludes the size of the eontaminant (how large or small the moleeule or partiele is) and on the pore size of the proteetive material (for instanee, impermeable rubber suits, tyveks, or eotton eoveralls). Chemieal eharaeteristies (i.e., polarity, vapor pressure, pH) of both the eontaminant and the proteetive material also determine permeability. Keep in mind that gases, vapors, and low-viseosity liquids tend to permeate more readily than high-viseosity liquids or solids [2],... 

Explosive Gases, Vapors, and Dust Mixtures References 432... 

Gases, vapors, and small dust particulates are distributed in the space by airflows produced by supply jets, convective flows, or air currents entering the building through the building apertures and cracks. Also, gases and vapors are distributed due to turbulent and molecular diffusion. Distribution of contaminants with airflows is significantly faster (hundreds of times) than distribution due to molecular diffusion. 

Some gases, vapors, and dust mixtures with air or oxygen may produce explosions. For explosion to occur, a flammable gas or combustible material... 

As the outside air conditions vary from hour to hour, day to day, and month to month, to economize on the heating and cooling loads, the recirculated and fresh airsrreams are mixed in varying proportions. If the air contains toxic or inflammable gases, vapors, or dusts, no direct mixing occurs, and a hcat-tccovery device is used. 

Gases, vapors, and fumes usually do not exhibit significant inertial effects. In addition, some fine dusts, 5 to 10 micrometers or less in diameter, will not exhibit significant inertial effects. These contaminants will be transported with the surrounding air motion such as thermal air current, motion of machinery, movement of operators, and/or other room air currents. In such cases, the exterior hood needs to generate an airflow pattern and capture velocity sufficient to control the motion of the contaminants. However, as the airflow pattern created around a suction opening is not effective over a large distance, it is very difficult to control contaminants emitted from a source located at a di,stance from the exhaust outlet. In such a case, a low-momentum airflow is supplied across the contaminant source and toward the exhaust hood. The... 

Air contaminants Aerosols, gases, vapors or dusts which may cause adverse effects if discharged into the indoor or outdoor atmosphere. 

Air-purifying respirator A respirator that removes airborne contaminants, such as particulates, gases, vapors and fumes, from ambient air through filtration, absorption, adsorption, or chemical reactions on the media contained in the cartridge or filter. 

Air treatment Any technique used to control the temperature, moisture content, or levels of dusts, gases, vapors, pollens, bacteria or viruses in air. 

Downdraft hood A hood positioned under a process that receives gases, vapors or dusts from the source above. 

Exhaust rate The controlled quantity of air, gases, vapors, and particulate matter that is removed from a space or process. 

Flammable atmosphere Any atmosphere that represents a fire or explosive hazard by virtue of gases, vapors, or dusts contained in it. 

Classification of Gases, Vapors and Dusts for Electrical Equipment in Hazardous (Classified) Locations... 

Many fires are started by careless or neglectful workers who do not abide by rules tliat proliibit smoking in areas containing flaimnable liquids, gases, vapors, dusts, fibers, and so on. ... 

Rapid release of energy dirough die ignition of atmospheric mixtures of flanuiiable gases, vapors or combustible dusts widiiii the explosive range... 

To determine acceptable contaminant levels in soils, two primary exposure routes are usually considered (1) inlialation of gases, vapors, or airborne particulate emanating from the site, and (2) ingestion of contamimtted drinking water. Other routes that can contribute to e.xposure include absorption of pollutants tluough direct skin contact and uptake of wtiter or soil contantinants by plants that are part of the food chain. 

ElecU ical Equipment in Hazardous (Class.) Locations, Gases, Vapors, Dusts 49VM... 

The flow of compressible and non-compressible liquids, gases, vapors, suspensions, slurries and many other fluid systems has received sufficient study to allow definite evaluation of conditions for a variety of process situations for Newtonian fluids. For the non-Newtonian fluids, considerable data is available. However, its correlation is not as broad in application, due to the significant influence of physical and rheological properties. This presentation is limited to Newtonian systems, except where noted. 

Flow coefficients (not resistance) for valves are generally available from the manufacturer. The coefficient of a valve is defined as tlie flow of water at 60°F, in gallons per minute, at a pressure drop of one pound per square inch across the valve [3], regardless of whether the valve ultimately will be flowing liquid or gases/vapors in the plant process. It is expressed ... 

For gases/vapors flowing in a pipe system from point 1 with pressure Pi and point 2 with pressure Po, the Pj - Po is the pressure drop, AP, between the points [3]. 

Figures 2-38A and 2-38B are based on the perfect gas laws and for sonic conditions at the outlet end of a pipe. For gases/vapors that deviate from these laws, such as steam, the same application will yield about 5% greater flow rate. For improved accuracy, use the charts in Figures 2-38A and 2-38B to determine the dowmstream pressure when sonic velocity occurs. Then use the fluid properties at this condition of pressure and temperature in ...

Somewhat unusual and/or unexpected mixtures of gases/vapors can form explosive mixtures. Some, but not all inclusive, of these include [34] ... 

Determination of Relief Areas for Deflagrations of Gases/Vapors/Mists in High Strength Enclosures... 

The importance of the stack height (see Figure 7-73) is (a) to discharge the burning venting gases/vapors sufficiently high into the air so as to allow safe dispersion and... 

The direct counter-current contact of a hot gas with a cool immiscihle liquid is effectively used in certain hydrocarbon cracking processes for the quenching of hot gases/vapors. Sometimes, the liquid used is oil and followed hy water quench, as is typical in ethylene plants cracking naphtha or other hydrocarbon as feed stock. 

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