A method for removing SO.sub.x from a gas by using a modified polyethylene glycol solution to absorb the SO.sub.x in the gas. The modified polyethylene glycol solution is contacted with the gas containing SO.sub.x to absorb the SO.sub.x in the gas, wherein x=2 and/or 3, the modified polyethylene glycol is a product derived from etherifying hydroxyl groups in the molecules of ethylene glycol and/or polyethylene glycol and has a general formula: R.sub.1—(O—C.sub.2H.sub.4).sub.n—O—R.sub.2, where n is a positive integer, R.sub.1 and R.sub.2 are the same or different and are each independently alkyl, alkenyl, alkynyl, acyl or aryl.

This invention relates to processes for selective removal of contaminants from effluent gases. A sulfur dioxide absorption/desorption process for selective removal and recovery of sulfur dioxide from effluent gases utilizes a buffered aqueous absorption solution comprising weak inorganic or organic acids or salts thereof, to selectively absorb sulfur dioxide from the effluent gas. Absorbed sulfur dioxide is subsequently stripped to regenerate the absorption solution and produce a sulfur dioxide-enriched gas. A process for simultaneous removal of sulfur dioxide and nitrogen oxides (NO.sub.x) from effluent gases and recovery of sulfur dioxide utilizes a buffered aqueous absorption solution including a metal chelate to absorb sulfur dioxide and NO.sub.x from the gas and subsequently reducing absorbed NO.sub.x to form nitrogen. A process to control sulfate salt contaminant concentration in the absorption solution involves partial crystallization and removal of sulfate salt crystals.

This invention relates to processes for selective removal of contaminants from effluent gases. A sulfur dioxide absorption/desorption process for selective removal and recovery of sulfur dioxide from effluent gases utilizes a buffered aqueous absorption solution comprising weak inorganic or organic acids or salts thereof, to selectively absorb sulfur dioxide from the effluent gas. Absorbed sulfur dioxide is subsequently stripped to regenerate the absorption solution and produce a sulfur dioxide-enriched gas. A process for simultaneous removal of sulfur dioxide and nitrogen oxides (NO.sub.x) from effluent gases and recovery of sulfur dioxide utilizes a buffered aqueous absorption solution including a metal chelate to absorb sulfur dioxide and NO.sub.x from the gas and subsequently reducing absorbed NO.sub.x to form nitrogen. A process to control sulfate salt contaminant concentration in the absorption solution involves partial crystallization and removal of sulfate salt crystals.

H2 production, sulfuric acid and SO2 production process refers to an innovative process VIA the phenomena of the Sulfur-Iodine (S-I) thermochemical cycle. The process consist of the acid gas burner to burn all the acid gases with air, enriched air or oxygen and without using any fuel gas to produce SO2. The acid gases are normally processed in the prior arts of the sulfur recovery units. Iodine is used to produce the hydrogen.

A portion or all of the acid gases are sent to the acid gas burner in accordance with the present invention.

The present innovation not only produces hydrogen but also reduces the SO2 and CO2 emissions.

The produced SO2 is sent to other units to produce other fertilizer products and the produced CO2 is sent to CO2 removal or CO2 Liquefaction process.

The hydrogen is produced is used to supply the needs within the facility like hydrotreaters to reduce external import and to reduce the operating costs.

H2 production, sulfuric acid and SO2 production process refers to an innovative process VIA the phenomena of the Sulfur-Iodine (S-I) thermochemical cycle. The process consist of the acid gas burner to burn all the acid gases with air, enriched air or oxygen and without using any fuel gas to produce SO2. The acid gases are normally processed in the prior arts of the sulfur recovery units. Iodine is used to produce the hydrogen.

A portion or all of the acid gases are sent to the acid gas burner in accordance with the present invention.

The present innovation not only produces hydrogen but also reduces the SO2 and CO2 emissions.

The produced SO2 is sent to other units to produce other fertilizer products and the produced CO2 is sent to CO2 removal or CO2 Liquefaction process.

The hydrogen is produced is used to supply the needs within the facility like hydrotreaters to reduce external import and to reduce the operating costs.

A water treatment tank includes: a tank body including a bottom surface extending in a horizontal direction; an overflow wall partitioning the inside of the tank body into an upstream tank into which treatment water having absorbed sulfur from an exhaust gas is introduced and a downstream tank into which the treatment water overflowing from the upstream tank is introduced to flow therein; and an inclined part that is provided between the bottom surface of the tank body and the overflow wall in the downstream tank and is inclined downward as it goes from the overflow wall toward a downstream side inside the downstream tank to be connected to the bottom surface of the tank body.

The invention is directed to a process and a system for removing sulfur dioxide from a feed gas stream. In the process the feed gas pre-scrubbed. Then SO2 is absorbed from the gas with an absorbing medium. The spent absorbing medium is regenerated. These process steps are interchanged with a caustic treatment in the pre-scrubbing zone in case of a very high SO2 content in the feed gas stream. The system comprises a pre-scrubbing unit, an absorption unit, and a regeneration unit. The system is characterized in that the pre-scrubber unit comprises an inlet for an aqueous solution comprising a strong base. These are a simple, cost-efficient and reliable process and facility for processing gas with a varying SO2 content.

The invention is directed to a process and a system for removing sulfur dioxide from a feed gas stream. In the process the feed gas pre-scrubbed. Then SO2 is absorbed from the gas with an absorbing medium. The spent absorbing medium is regenerated. These process steps are interchanged with a caustic treatment in the pre-scrubbing zone in case of a very high SO2 content in the feed gas stream. The system comprises a pre-scrubbing unit, an absorption unit, and a regeneration unit. The system is characterized in that the pre-scrubber unit comprises an inlet for an aqueous solution comprising a strong base. These are a simple, cost-efficient and reliable process and facility for processing gas with a varying SO2 content.

The invention is directed to a process and a system for removing sulfur dioxide from a feed gas stream. In the process the feed gas pre-scrubbed. Then SO2 is absorbed from the gas with an absorbing medium. The spent absorbing medium is regenerated. These process steps are interchanged with a caustic treatment in the pre-scrubbing zone in case of a very high SO2 content in the feed gas stream. The system comprises a pre-scrubbing unit, an absorption unit, and a regeneration unit. The system is characterized in that the pre-scrubber unit comprises an inlet for an aqueous solution comprising a strong base. These are a simple, cost-efficient and reliable process and facility for processing gas with a varying SO2 content.

The invention is directed to a process and a system for removing sulfur dioxide from a feed gas stream. In the process the feed gas pre-scrubbed. Then SO2 is absorbed from the gas with an absorbing medium. The spent absorbing medium is regenerated. These process steps are interchanged with a caustic treatment in the pre-scrubbing zone in case of a very high SO2 content in the feed gas stream. The system comprises a pre-scrubbing unit, an absorption unit, and a regeneration unit. The system is characterized in that the pre-scrubber unit comprises an inlet for an aqueous solution comprising a strong base. These are a simple, cost-efficient and reliable process and facility for processing gas with a varying SO2 content.