Provided is a method for treatment of gas mixtures and an apparatus for carrying out a method for treatment of raw gas mixtures. More particularly, there is provided a method and an apparatus for treatment of gas mixtures, such as biogas or flare gas, and in particular to a method and an apparatus for removing contaminants, in particular H.sub.2S, from a gas mixture containing CH.sub.4 and H.sub.2S.

A method and system for removing at least dissolved hydrogen sulphide or another targeted constituent from a feedstock is provided wherein the targeted constituent has a gas: liquid equilibrium. In some embodiments, the method includes the steps of: contacting the feedstock in at least one stripping vessel with a stripping gas to produce a gas stream containing at least hydrogen sulphide gas; conveying the gas stream from the at least one stripping vessel to an oxidation reactor; contacting the gas stream with an oxidizing agent in the oxidation reactor so as to oxidize the at least hydrogen sulphide gas to produce sulphuric acid; and conveying the produced sulphuric acid from the oxidation reactor to the at least one stripping vessel so as to reduce a pH value of the feedstock within the stripping vessel.

A method and system for removing at least dissolved hydrogen sulphide or another targeted constituent from a feedstock is provided wherein the targeted constituent has a gas: liquid equilibrium. In some embodiments, the method includes the steps of: contacting the feedstock in at least one stripping vessel with a stripping gas to produce a gas stream containing at least hydrogen sulphide gas; conveying the gas stream from the at least one stripping vessel to an oxidation reactor; contacting the gas stream with an oxidizing agent in the oxidation reactor so as to oxidize the at least hydrogen sulphide gas to produce sulphuric acid; and conveying the produced sulphuric acid from the oxidation reactor to the at least one stripping vessel so as to reduce a pH value of the feedstock within the stripping vessel.

Acid gas compounds are removed from a process gas such as, for example, syngas or natural gas, by flowing a feed gas into a desulfurization unit to remove a substantial fraction of sulfur compounds from the feed gas and flowing the resulting desulfurized gas into a CO.sub.2 removal unit to remove a substantial fraction of CO.sub.2 from the desulfurized gas.

Acid gas compounds are removed from a process gas such as, for example, syngas or natural gas, by flowing a feed gas into a desulfurization unit to remove a substantial fraction of sulfur compounds from the feed gas and flowing the resulting desulfurized gas into a CO.sub.2 removal unit to remove a substantial fraction of CO.sub.2 from the desulfurized gas.

An electrocoagulation unit for removing one or more dissolved constituents from an untreated feedstock comprises a non-electrically conductive housing having a fluid inlet, a fluid outlet and an interior surface; a cathode and anode arranged within the housing, the cathode and anode each having an ionizing surface, the ionizing surfaces of the anode and cathode in opposed facing relation so as to define a gap having a separation distance therebetween; the cathode and the anode configured to be electrically coupled to a DC power supply in a DC electrical circuit so as to ionize and dissolve the ionizing surface of the anode; and a controller configured to maintain the separation distance at a set value as the ionizing surface of the anode dissolves. A method for using a plurality of electrocoagulation units in series is also provided.

A plant for the production of sulfur trioxide from a feed stream containing sulfur-containing compounds and dissolved metals and alkali metals by a process, which involves gas quenching, comprises an incineration furnace, a mixing device and/or a dilution air heater, a dust removal device and an SO.sub.2 converter. The plant may further comprise a condenser for the purpose of producing sulfuric acid.

A plant for the production of sulfur trioxide from a feed stream containing sulfur-containing compounds and dissolved metals and alkali metals by a process, which involves gas quenching, comprises an incineration furnace, a mixing device and/or a dilution air heater, a dust removal device and an SO.sub.2 converter. The plant may further comprise a condenser for the purpose of producing sulfuric acid.

A process for preparing sulfuric acid may involve melting elemental sulfur in a melting stage to give molten sulfur. Sulfuric acid is subsequently produced from the molten sulfur. Further, sulfur-containing offgases formed in the melting stage may be subjected to oxidation in a supplementary oxidation stage in which sulfur-containing components of the offgases are oxidized to sulfur dioxide. The process may further involve processing the sulfur dioxide to give at least one reaction product. The melting stage may be operated without emissions by processing all of the offgases from the melting stage. An apparatus may be employed for carrying out such a process.

A process for preparing sulfuric acid may involve melting elemental sulfur in a melting stage to give molten sulfur. Sulfuric acid is subsequently produced from the molten sulfur. Further, sulfur-containing offgases formed in the melting stage may be subjected to oxidation in a supplementary oxidation stage in which sulfur-containing components of the offgases are oxidized to sulfur dioxide. The process may further involve processing the sulfur dioxide to give at least one reaction product. The melting stage may be operated without emissions by processing all of the offgases from the melting stage. An apparatus may be employed for carrying out such a process.