A gas laser apparatus may include: a laser chamber connected through a first control valve to a first laser gas supply source that supplies a first laser gas containing a halogen gas; a purification column that removes at least a part of the halogen gas and a halogen compound from at least a part of a gas exhausted from the laser chamber; a booster pump; and a controller that calculates, on a basis of a first amount of a gas supplied from the booster pump to the laser chamber, a second amount of the first laser gas that is to be supplied to the laser chamber and controls the first control valve on a basis of a result of the calculation of the second amount.

A particulate composition said composition comprises a metal carbonate and/or a metal bicarbonate and a compound of aluminium, characterised in that the weight ratio of metal carbonate plus metal bicarbonate compounds to said compound of aluminium is at least 3:1. The composition is useful for removing halogenated compounds from a hydrocarbon-containing process stream.

An agent for removing a halogen gas, such as chlorine, in a waste gas by means of reduction; a method for producing this agent; a method for removing a halogen gas by use of this agent; and a system for removing a halogen gas. The agent for removing the halogen gas contains at least pseudo-boehmite, that serves as a host material, and a sulfur-containing reducing agent, that serves as a guest material. 1-8% by weight of the reducing agent, in terms of elemental sulfur, based on the total amount of the pseudo-boehmite and sulfur-containing reducing agent is present in the agent. At least one inorganic compound selected from among oxides, carbonates salts and hydrocarbon salts of alkaline earth metal elements, transition metal elements and zinc group elements is additionally contained in the agent as a third component.

An electrical switching device is provided for interrupting an electrical connection. The device has a switching chamber and two contact pieces being arranged directly in the switching chamber or in an encapsulated housing arranged in the switching chamber and configured to be gas-tight in relation to the switching chamber. The contact pieces are movable relative to each other to bring about a switching action. A fluid insulation medium is also provided, which is arranged in the switching chamber or in a storage volume which can be connected to the switching chamber. The switching chamber or the storage volume has an outlet for letting out the fluid insulation medium. A filter is provided at or adjacent to the outlet, the filter configured to filter gaseous components of the insulation medium, or the reaction products thereof, conducted through the outlet.

Several embodiments of the present technology are directed to the removal of one or more air pollutants using cooling and/or calcium-containing particles. In some embodiments, a method for removing air pollutants comprises flowing a gas stream having calcium-containing particles and one or more of mercury or hydrochloric acid molecules, and cooling the gas stream, thereby causing at least a portion of the calcium-containing particles to adsorb to the mercury and/or hydrochloric acid molecules in the gas stream. The method can further comprise, after cooling the gas stream, filtering the gas stream to remove at least a portion of the calcium-containing particles having adsorbed mercury and hydrochloric acid.

A gas purification system may include: a circulation gas pipe in which a second end is connected at a first position to a second pipe through which gas is supplied from a gas supply source; a booster pump; a gas purification unit; a first tank in the circulation gas pipe; a first valve positioned between the gas supply source and the first position, the first valve having an open position and a closed position; and a second valve positioned between the first tank and the second end, the second valve having an open position and a closed position, the second valve configured to be in the closed position when the first valve is in the open position.

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 less than 20, wherein individual particles include a surface area greater than or equal to about 25 m.sup.2/g.

A hydrated lime product exhibiting superior reactivity towards HCl and SO.sub.2 in air pollution control applications. Also disclosed is a method of providing highly reactive hydrated lime and the resultant lime hydrate where an initial lime feed comprising calcium and impurities is first ground to a particle-size distribution with relatively course particles. Smaller particles are then removed from this ground lime and the smaller particles are hydrated and flash dried to form a hydrated lime, which is then milled to a significantly smaller particle size than that of the relatively course particles. The resultant lime hydrate product has available CaOH of greater than 92%, a citric acid reactivity of less than 20 seconds, a BET surface area greater than 18, a D90 less than 10 m, a D50 less than 4 m, a D90/D50 less than 3, and a large pore volume of greater than 0.2 BJH.

A hydrated lime product exhibiting superior reactivity towards HCl and SO.sub.2 in air pollution control applications. Also disclosed is a method of providing highly reactive hydrated lime and the resultant lime hydrate where an initial lime feed comprising calcium and impurities is first ground to a particle-size distribution with relatively course particles. Smaller particles are then removed from this ground lime and the smaller particles are hydrated and flash dried to form a hydrated lime, which is then milled to a significantly smaller particle size than that of the relatively course particles. The resultant lime hydrate product has available CaOH of greater than 92%, a citric acid reactivity of less than 20 seconds, a BET surface area greater than 18, a D90 less than 10 m, a D50 less than 4 m, a D90/D50 less than 3, and a large pore volume of greater than 0.2 BJH.

Several embodiments of the present technology are directed to the removal of one or more air pollutants using cooling and/or calcium-containing particles. In some embodiments, a method for removing air pollutants comprises flowing a gas stream having calcium-containing particles and one or more of mercury or hydrochloric acid molecules, and cooling the gas stream, thereby causing at least a portion of the calcium-containing particles to adsorb to the mercury and/or hydrochloric acid molecules in the gas stream. The method can further comprise, after cooling the gas stream, filtering the gas stream to remove at least a portion of the calcium-containing particles having adsorbed mercury and hydrochloric acid.