Abatement of high concentrations of acid gas emissions
AssigneeTeller Environmental Systems, Inc.
InventorAaron Joseph Teller
Life of this patent
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Abstract
A process is disclosed for the large-scale abatement of acid gases in hot industrial effluent gas streams. In a first stage, the proportion of acid gases in a hot gas stream containing a relatively high initial concentration of acid gases is substantially reduced by contacting the gas stream with an aqueous solution or slurry of a basic material capable of reacting with the acid gases under such conditions that a dry salt is left as the reaction product. In subsequent steps, particulate material and residual acid gases are removed from the gas stream either: 1) by introducing into the gas stream a particulate material capable of sorbing acid gases followed by a particulate removal step; or, 2) by using a wet scrubber.
Claims16
A process for treating effluent gases having a temperature above about 350.degree.F. and initially containing high concentrations of sulfur oxides, nitrogen oxides, hydrogen halides, silicon tetrafluoride and mixtures thereof to reduce the concentrations of these acid gases to environmentally required levels, comprising the following steps:
- 1. First treating the effluent gases to remove a predominant portion of the acid gases by the steps of:
- a. spraying into said effluent gases an aqueous solution or slurry of a basic material selected from the group consisting of:
- the oxides, hydroxides, carbonates and bicarbonates of the alkali metals, alkaline earth metals, zinc, nickel, copper and iron;
- nepheline syenite and phonolite;
- and mixtures thereof;
- b. adjusting the concentration of basic material in said solution or slurry and the rate of addition of solution or slurry such that 60-95% of the acid gases initially present react with said basic material for form a solid salt reaction product and the hot effluent gases rapidly evaporate substantially all of the liquid water thereby cooling the effluent gases to a temperature below about 250.degree.F. and humidifying the gases to a relative humidity of about 20-50%;
- and,
- c. separating the larger solid salt particles from the effluent gases by gravity;
- and,
- 2.
A process for treating effluent gases having a temperature above about 350.degree.F. and initially containing high concentrations of sulfur oxides, nitrogen oxides, hydrogen halides, silicon tetrafluoride and mixtures thereof to reduce the concentrations of these acid gases to environmentally required levels, comprising the following steps:
- 1. First treating the effluent gases to remove a predominant portion of the acid gases by the steps of:
- a. spraying into said effluent gases an aqueous solution or slurry of a basic material selected from the group consisting of:
- the oxides, hydroxides, carbonates and bicarbonates of the alkali metals, alkaline earth metals, zinc, nickel, copper and iron;
- nepheline syenite and phonolite;
- and mixtures thereof;
- b. adjusting the concentration of basic material in said solution or slurry and the rate of addition of solution such that 60-95% of the acid gases initially present react with said basic material for form a solid salt reaction product and the hot effluent gases rapidly evaporate substantially all of the liquid water thereby cooling the effluent gases to a temperature above about 150.degree.F. to about 212.degree.F. and humidifying the gases substantially to saturation;
- and,
- c. seaparating the larger solid salt particles from the effluent gases by gravity;
- 2. Initiating nucleation of the residual particulates in the effluent gases by treating the gases, at a temperature above about 150.degree.F. to about 212.degree.F. and humidified substantially to saturation, in an intermediate enclosure to increase turbulence in the gases;
- and
- 3. Thereafter further treating the effluent gases for the removal of residual acid gases and particles by the steps of:
- a. passing said effluent gases which are at a temperature above about 150.degree.F. to about 212.degree.F. and substantially saturated in a substantially horizontal path through an enclosure containing packing;
- b. passing an aqueous scrubbing liquid downwardly over said packing;
- c. exhausting said effluent gases from said enclosure containing packing substantially free of residual acid gases and solid particles;
- and,
- d. collecting said scrubbing liquid after passage through said packing and recirculating said liquid to said packing while maintaining it at a substantially constant temperature approximately the same as the saturated gases which is above about 150.degree.F. to about 212.degree.F.
Dependencies are inferred from the claim text.