Calcium hydroxide-containing compositions can be manufactured by slaking quicklime, and subsequently drying and milling the slaked product. The resulting calcium hydroxide-containing composition can have a size, steepness, pore volume, and/or other features that render the compositions suitable for treatment of exhaust gases and/or removal of contaminants. In some embodiments, the calcium hydroxide-containing compositions can include a D.sub.10 from about 0.5 microns to about 4 microns, a D.sub.90 less than about 30 microns, and a ratio of D.sub.90 to D.sub.10 from about 8 to about 20, wherein individual particles include a surface area greater than or equal to about 25 m.sup.2/g.

A radial air purification system, a method of forming the purification system, and methods of removing at least one contaminant from a gas using the purification system are provided. The radial air purification system includes adsorbent media tubular supports that are fabricated using a fiberglass grating structure to provide increased strength, corrosion resistance, reduction in weight, and lower fabrication costs.

Refrigeration systems with a purge for removing non-condensables from the refrigerant and an acid filter for remove acid from the refrigerant are provided. The acid filter can be operatively connected to the purge. Optionally, the purge can include a separating device for separating non-condensable gases from condensable refrigerant gases and an acid filter is provided to remove acid from the condensable refrigerant gases.

A contaminated gas stream can be passed through an in-line mixing device, positioned in a duct containing the contaminated gas stream, to form a turbulent contaminated gas stream. One or more of the following is true: (a) a width of the in-line mixing device is no more than about 75% of a width of the duct at the position of the in-line mixing device; (b) a height of the in-line mixing device is no more than about 75% of a height of the duct at the position of the in-line mixing device; and (c) a cross-sectional area of the mixing device normal to a direction of gas flow is no more than about 75% of a cross-sectional area of the duct at the position of the in-line mixing device. An additive can be introduced into the contaminated gas stream to cause the removal of the contaminant by a particulate control device.

A process for generating calcium fluoride particles having a particle size (d50) of from about 15 m to about 300 m. The process features contacting a gas stream having gaseous hydrogen fluoride (HF) with a fluidized bed of calcium carbonate particles in a fluidized bed reactor.

A hydrogen fluoride gas removal device has: a hydrogen fluoride gas removal treatment machine that is configured to perform a treatment of removing hydrogen fluoride gas from the mixed gas by bringing the mixed gas into contact with a removal agent for removing the hydrogen fluoride gas from the mixed gas; a removal agent supply machine that is configured to supply the removal agent to the hydrogen fluoride gas removal treatment machine; a removal agent recycling treatment machine that is configured to perform a recycling treatment on the used removal agent to improve hydrogen fluoride gas removal performance of the removal agent; and a recycling-treated removal agent transport machine that is configured to transport the recycling-treated removal agent to supply the removal agent to the removal agent supply machine.

A heated inlet tube for use in a wet scrubber is disclosed. In one embodiment, the heated inlet tube comprises a heated tube concentric to the inlet tube to which a heated gas is applied thereby maintaining temperature of a waste gas stream as it flows through the inlet tube. In a further embodiment, an insulating tube concentrically surrounds the heated tube to further maintain the temperature of the waste gas stream.

Calcium hydroxide-containing compositions can be manufactured by slaking quicklime, and subsequently drying and milling the slaked product. The resulting calcium hydroxide-containing composition can have a size, steepness, pore volume, and/or other features that render the compositions suitable for treatment of exhaust gases and/or removal of contaminants. In some embodiments, the calcium hydroxide-containing compositions can include a D.sub.10 from about 0.5 microns to about 4 microns, a D.sub.90 less than about 30 microns, and a ratio of D.sub.90 to D.sub.10 from about 8 to about 20, wherein individual particles include a surface area greater than or equal to about 25 m.sup.2/g.

A contaminated gas stream can be passed through an in-line mixing device, positioned in a duct containing the contaminated gas stream, to form a turbulent contaminated gas stream. One or more of the following is true: (a) a width of the in-line mixing device is no more than about 75% of a width of the duct at the position of the in-line mixing device; (b) a height of the in-line mixing device is no more than about 75% of a height of the duct at the position of the in-line mixing device; and (c) a cross-sectional area of the mixing device normal to a direction of gas flow is no more than about 75% of a cross-sectional area of the duct at the position of the in-line mixing device. An additive can be introduced into the contaminated gas stream to cause the removal of the contaminant by a particulate control device.

A system and a method for industrial plant or utility plant flue gas desulfurization, with zero waste water liquid discharge from a wet flue gas desulfurization system utilized therein, are disclosed herein. The wet flue gas desulfurization system is supplied an absorption liquid for contact with a flue gas to absorb flue gas acid gases. Waste water from the wet flue gas desulfurization system is heated under pressure in a heat exchanger to produce heated waste water, which is supplied to a flash vessel to produce steam. The produced steam is supplied to the flue gas upstream of a particulate collection system and the wet flue gas desulfurization system, supplied to the flue gas upstream of the wet flue gas desulfurization system, or supplied to absorption liquid circulated to the wet flue gas desulfurization system.