Scrubbers chemical

Sodium hydroxide, caustic soda Electrolytic Chlorine Mercury Alkaline scrubbers Chemical scrubbing and adsorbers... 

Scrubbers, chemical, 255, 269 Sensitivity to photochemical oxidants, by plants, 470-71... 

Figure 11.2 Various types of scrubbers can be used to treat air pollution from solid particles. (Reproduced with permission from Stenhouse, Pollution Control in Teja, Chemical Engineering and the Environment, Blackwell Scientific Publications, Oxford, U.K., 1981.)...

FIG. 17-49 Self-induced spray scrubbers, a) Blaw-Knox Food Chemical Equipment, Inc. (h) American Air Filter Co., Inc. 

Fiberglass manufacturing scrubber sludge Secondary and synthetic fiber Chemicals Variable-volume filter press 3 37... 

The principal technological developments in the control of air pollution by engineering during the nineteenth century were the stoker for mechanical firing of coal, the scrubber for removing acid gases from effluent gas streams, cyclone and bag house dust collectors, and the introduction of physical and chemical principles into process design. 

Dry aerosols, or particulate matter, differ so much from the carrying gas stream that their removal should present no major difficulties. The aerosol is different physically, chemically, and electrically. It has vastly different inertial properties than the carrying gas stream and can be subjected to an electric charge. It may be soluble in a specific liquid. With such a variety of removal mechanisms that can be applied, it is not surprising that particulate matter, such as mineral dust, can be removed by a filter, wet scrubber, or electrostatic precipitator with equally satisfactory results. 

Venmri scrubbers have been applied to control PM emissions from utility, industrial, commercial, and institutional boilers fired with coal, oil, wood, and liquid waste. They have also been applied to control emission sources in the chemical, mineral products, wood, pulp and paper, rock products, and asphalt manufacrnring industries lead, aluminum, iron and steel, and gray iron production industries and to municipal solid waste incinerators. Typically, venturi scrubbers are applied where it is necessary to obtain high collection efficiencies for fine PM. Thus, they are applicable to controlling emission sources with high concentrations of submicron PM. 

The suitability of gas absorption as a pollution control method is generally dependent on the following factors 1) availability of suitable solvent 2) required removal efficiency 3) pollutant concentration in the inlet vapor 4) capacity required for handling waste gas and, 5) recovery value of the pollutant(s) or the disposal cost of the unrecoverable solvent. Packed-bed scrubbers are typically used in the chemical, aluminum, coke and ferro-alloy, food and agriculture, and chromium electroplating industries. 

The discharge of copious quantities of chemicals directly to the atmosphere can give rise to secondary hazards, especially if the materials are toxic and can form a flammable atmosphere (e.g., vapor or mist) in air. In such cases, the provision of a knockout device (scrubber, dump tank) of adequate size to contain the aerated/foaming fluid is required. 

Scrubbers often convert an air pollution problem into a water pollution problem. If regulations require 100% recycling, the scrubber water may require flocculants or neutralizing chemicals or both. Corrosion can be a serious problem requiring high maintenance or special materials of construction. 

Packed-tower wet scrubber A gas scrubber that removes gases and vapors, by using either v/ater or a chemical liquid method. Efficient pollutant removal depends on the contact time between the entering gas stream and the wetted surface of the pack in the tower. This type of scrubber can be classified as... 

POLLUTION CONTROL EQUIPMENT 8000-8999. Wet Scrubbers 8000-8099. .Chemical Supply 8100-8199. .Scrubber... 

Over the past decades, advances have been made that reduce environmental impacts of coal burning in large plants. Some arc standard and others experimental. Limestone (mainly calcium carbonate) scrubber smokestacks react with the emitted sulfates from the combustion and contain the chemical products, thereby reducing the release of SO., into the atmosphere by a large factor (of ten or more). Pulverization of coal can also allow for the mechanical separation of some sulfur impurities, notably those in the form of pyrites, prior to combustion. Currently deployed—with more advanced versions in the development stage—are various t yies of fluidized bed reactors, which use coal fuel in a pulverized form, mixed with pulverized limestone or dolomite in a high temperature furnace. This technique reduces sulfate release considerably. There are... 

Figure 4-59. Venturi scrubber. Courtesy of Chemical Construction Corp.

Typical BW antifoam emulsion products include SAG 10 and SAG 30 (10 and 30% milky white emulsions, each with a viscosity of 2,000 cS at 25 °C) from Union Carbide Corporation. These same products also are used for food processing (under FDA 21CFR 173.340), for petroleum processing (as amine scrubbers, gas-oil separators, etc.), and as functional chemicals (antifreezes, hydraulic fluids, cutting oils, etc.). 

Other methods have been developed for the removal of oxygen (particularly from flowing streams). These include the use of electrochemical or chemical (zinc) scrubbers, nitrogen-activated nebulizers, and chemical reduction (by addition of sodium sulfite or ascorbic acid). Alternately, it may be useful to employ voltam-... 

Exhaust conditioning requires a precise identification of all the gases and liquids, both residual precursors and by-products. It also requires leak-tight piping and ducts, and suitable mechanical and chemical scrubbers to remove or neutralize dangerous materials and the proper venting of the mechanical pump with a stainless exhaust filter to remove oil mist at the source. 

Work out the full chemical engineering design of the reactor and cooler/scrubber systems. 

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