A process for the cleaning of a lean gas stream contaminated with volatile organic compounds (VOCs) and/or sulfur-containing compounds comprises the steps of adding ozone to the contaminated lean gas stream, subjecting the ozone-containing lean gas stream to ultraviolet irradiation, thereby transforming VOCs to particles, maintaining the irradiated gas stream in a stay zone for a sufficient time to allow aerosol particle growth, and passing the gas stream through a catalytic bag filter at a temperature down to room temperature to remove the formed particles and eliminate any remaining ozone. The bag filter has been made catalytic by impregnation with one or more metal oxides in which the metals are selected from V, W, Pd and Pt, supported on TiO.sub.2.

Disclosed herein are systems and methods for reducing the particulate matter content of an exhaust gas from a carbon black process.

Disclosed herein are systems and methods for reducing the particulate matter content of an exhaust gas from a carbon black process.

Provided is a wet desulfurization process using a suspension bed. The process comprises mixing desulfurization slurry with a hydrogen sulfide containing gas to obtain a first mixture, and passing the first mixture into a suspension bed reactor from bottom to top, with controlling the first mixture to have a dwell time of 5-60 minutes in the reactor to allow they contact and react sufficiently with each other; and subjecting a second mixture obtained from the reaction to gas liquid separation to produce a purified gas. The process of the present invention may reduce the hydrogen sulfide content in the hydrogen sulfide containing gas from 2.4-140 g/Nm.sup.3 to 50 ppm or less, so that the desulfurization efficiency is 98% or more. The process of the present invention is simple and reasonable, with high desulfurization and regeneration efficiency, simple equipment, little occupation of land and low investment, which is very suitable for industrial promotion.

A process for treating an H.sub.2S- and CO.sub.2-comprising fluid stream, in which a) the fluid stream is treated in a first absorber at a pressure of 10 to 150 bar with a first substream of a regenerated H.sub.2S-selective absorbent to obtain a treated fluid stream and an H.sub.2S-laden absorbent; b) the H.sub.2S-laden absorbent is heated by indirect heat exchange with regenerated H.sub.2S-selective absorbent; c) the heated HS-laden absorbent is decompressed to a pressure of 1.2 to 10 bar in a low-pressure decompression vessel to obtain a first CO.sub.2-rich offgas and a partly regenerated absorbent; d) the partly regenerated absorbent is regenerated in a desorption column to obtain an H.sub.2S-rich offgas and regenerated absorbent; e) the H.sub.2S-rich offgas is fed to a Claus unit and the offgas from the Claus unit is fed to a hydrogenation unit to obtain hydrogenated Claus tail gas; f) the hydrogenated Claus tail gas and the first CO.sub.2-rich offgas are treated in a second absorber at a pressure of 1 to 4 bar with a second substream of the regenerated H.sub.2S-selective absorbent to obtain a second CO.sub.2-rich offgas and a second H.sub.2S-laden absorbent; and g) the second H.sub.2S-laden absorbent is guided into the first absorber. Also described is a plant suitable for performance of the process. The process is notable for a low energy requirement.

A combustible gas from carbon black production is utilized in a gas engine by adding an oxygen-containing gas to the combustible gas, passing said mixed gas over a selective catalyst, which is active for oxidizing H.sub.2S to SO.sub.2 but substantially inactive for oxidation of CO, H.sub.2 and other hydrocarbons with less than 4 C-atoms, passing the converted gas through an SO.sub.2 removal step, and passing the cleaned gas to a gas engine or to an energy recovery boiler. This way, the tail gas from carbon black production, which is normally combusted in a CO boiler or incinerated, can be utilized to good effect.

A multifunctional air purifying device for removing indoor pollution by a thermal decomposition method comprises an air treatment unit and an air collection heater. The air collection heater is provided with an infrared lamp tube and an ultraviolet lamp tube. An annular water tank is arranged on an inner side of the upper part of the air treatment unit. A filter screen runs through the annular water tank and is connected with an air cap, and a fan is provided at a joint between the filter screen and the air cap. The filter screen includes an early effect filter screen, a HEPA filter screen, an activated carbon filter screen and a cold catalyst filter arranged in that order from a bottom to a top. A humidifier connects the annular sink and a nozzle located at an exhaust port.

The present application solves the existing problem of using very expensive oxidation reagents, such as H.sub.2O.sub.2 and ozone, in removal of NO.sub.x and SO.sub.x from the flue gases, by performing the NO.sub.x and SO.sub.x oxidation with atmospheric oxygen. The combined system for catalytic oxidation and wet-scrubbing of simultaneously both NO.sub.x and SO.sub.x from a flue gas and manufacturing fertilisers, comprises: (a) an air separation unit for separating atmospheric oxygen from air and thereby producing an air stream substantially enriched with atmospheric oxygen for oxidation of NO.sub.x and SO.sub.x, (b) an adsorption and oxidation reactor containing an oxidation catalyst and designed to receive said air stream and a flue gas stream containing NO.sub.x and SO.sub.x, to adsorb said streamed gases, and then to carry out the catalytic oxidation of said NO.sub.x and SO.sub.x by said oxygen to yield nitric and sulphuric acids, (c) a separator and reactor control unit for separation of products and liquids and controlling said catalytic oxidation and wet-scrubbing; and (d) a vessel containing gas or liquid ammonia, connected to said adsorption and oxidation reactor or to said separator and reactor control unit, and streaming said ammonia into the adsorption and oxidation reactor or into the separator and reactor control unit to react with the nitric and sulphuric acids and to yield ammonium nitrate and ammonium sulphate fertilisers.

A device (1) for generating clean air in a measuring apparatus, comprising: a duct (2) having an inlet and an outlet for the passage of an air flow to be cleaned; a platinum wire (3), positioned inside the duct (2), for intercepting the air flow to be cleaned, the platinum wire (3) is inserted in an electrical circuit (17) connectable to an electricity supply (15) to be operatively crossed by an electrical current.

A sorbent composition for removing mercury from flue gas is provided. The sorbent composition contains at least a powdered sorbent, an oxidant and a catalyst. Methods of cleaning flue gas are also provided, which includes injecting the sorbent composition into the flue gas, wherein the powdered sorbent has a fifty percent distribution particle size of from about 25 micrometers to about 75 micrometers.