Method for reducing the content of nitrogen oxides NOx and nitrous oxide N2O in an input gas, comprising the steps of: treating said gas with a first amount of a NOx reducing agent in a first de-NOx catalytic bed; treating the effluent of said first de-NOx catalytic bed in at least one de-N2O catalytic bed for removal of N2O; treating the effluent of said at least one de-N2O catalytic bed with a second amount of a NOx reducing agent in a second de-NOx catalytic bed.

An apparatus is provided for carrying out a process for removing N.sub.2O and NO.sub.x from offgases by catalytic decomposition of N.sub.2O by means of iron-containing zeolite catalysts and catalytic reduction of the NO.sub.x by means of reducing agents, the deNO.sub.x stage connected downstream of the deN.sub.2O stage being operated at inlet temperatures of T<=400 C., and the inlet gas for the deN.sub.2O stage comprising water and having a selected N.sub.2O/NO.sub.x ratio, and the operating parameters of temperature, pressure and space velocity of the deN.sub.2O stage being selected so as to result in an N.sub.2O degradation of 80 to 98%. Under these conditions, a degree of NO.sub.x oxidation of 30-70% is established at the outlet of the deN.sub.2O stage, which is defined as the ratio of the molar amounts of NO.sub.2 to the total molar amount of NO.sub.x. The result of this is that the downstream deNO.sub.x stage can be operated under optimal conditions.

Methods for the combined elimination of both ammonia and lower alkanes and/or hydrogen, which are contained in one or more waste gas streams in an industrial plant, are disclosed herein. The method is effectuated by combined oxidation and reduction according to the reduction-oxidation process, wherein the ammonia and the lower alkanes and/or hydrogen are completely or partially reacted by chemical reaction to form nitrogen, carbon dioxide and water. The waste gas stream containing ammonia and lower alkanes and/or hydrogen is passed over one or more catalysts for the combined oxidation and reduction, and the oxygen content in the waste gas stream is set in such a way that ammonia and the lower alkanes and/or hydrogen are oxidized first in an oxidation zone to form nitrogen, carbon dioxide and water, and the nitrogen oxides resulting therefrom are subsequently reduced in a reduction zone to form elemental nitrogen.

A carbon dioxide recovery apparatus has a separator which separates carbon dioxide from a gas by utilizing adsorption and desorption of carbon dioxide to and from an adsorbent caused by pressure fluctuation, the separator including a pressurizer which pressurizes the gas to a pressure that the adsorbent is capable of adsorbing carbon dioxide, and has a dryer having a hygroscopic agent for drying the gas. A regeneration system supplies the residual gas discharged from the separator to the dryer as a regeneration gas for regenerating the hygroscopic agent in the dryer, and the regeneration gas to be supplied to the dryer is heated by an energy converter by utilizing a pressure of a post-regeneration gas discharged by the regeneration of the hygroscopic agent.

Methods and systems are provided for producing solid carbon from carbon dioxide and/or hydrocarbons such as methane (CH.sub.4). A metallic media, either in liquid or semi-liquid (semi-solid) form and having a range of liquid and semi-liquid metallic chemistries, is used alone or in combinations with other liquid or semi-liquid metalin a reactive metallurgical process for carbon capture and conversion.

A process for removing N.sub.2O and NO.sub.x from offgases by catalytic decomposition of N.sub.2O by means of iron-containing zeolite catalysts and catalytic reduction of the NO.sub.x by means of reducing agents, the deNO.sub.x stage connected downstream of the deN.sub.2O stage being operated at inlet temperatures of T<=400 C., and the inlet gas for the deN.sub.2O stage comprising water and having a selected N.sub.2O/NO.sub.x ratio, and the operating parameters of temperature, pressure and space velocity of the deN.sub.2O stage being selected so as to result in an N.sub.2O degradation of 80 to 98%. Under these conditions, a degree of NO.sub.x oxidation of 30-70% is established at the outlet of the deN.sub.2O stage, which is defined as the ratio of the molar amounts of NO.sub.2 to the total molar amount of NO.sub.x. The result of this is that the downstream deNO.sub.x stage can be operated under optimal conditions. Also provided is an apparatus for carrying out the process.

A fossil fuel fired power plant exhaust gas clean-up and recovery system is provided to remove detrimental compounds/elements from the exhaust gas emitting from the power plant to protect the environment and to recover useful products from the cleaning solution. This is accomplished by directing the exhaust gas from the fossil fuel fired power plant through a single wet scrubber having a cleaning solution of a predetermined pH. The cleaning solution is composed of calcium carbonate and water. A recovery process is attached thereto to reclaim calcium carbonate, calcium sulfate, and carbon dioxide for reuse in the process and/or for commercial use.

A fossil fuel fired power plant exhaust gas conversion to syngas is provided. The exhaust gases being emitted from the power plant is normally cleaned and exhausted to the atmosphere. In the subject arrangement, the exhaust gases are directed through a wet scrubber and a reaction chamber to respectively remove sulfur and carbon dioxide. The cleaned exhaust gases are directed through an electrolysis process or a water-gas shift reactor to controllably produce extra hydrogen for use in the cleaned exhaust gas to obtain a desired ratio between the hydrogen and carbon monoxide therein. The resulting desired ratio in the exhaust gas between the hydrogen and carbon monoxide is the syngas that can be used for commercial applications.

Processes and facilities for recovering and purifying a pyrolysis gas formed by pyrolyzing waste plastic are provided. One or more treatment processes may be used to treat the pyrolysis gas for use in one or more downstream chemical recycling processes. which can be used in forming a variety of recycled content products. The treatment processes may include a halogen removal system and/or a sulfur removal system.

Provided are: an NOx removal unit to remove nitrogen oxide; an air preheater on a downstream side of the NOx removal unit to recover heat; a precipitator on a downstream side of the air preheater to remove ash dust; a gas-liquid contact type desulfurization unit on a downstream side of the precipitator to remove sulfur oxide; an SO.sub.3 removing agent supply unit to supply an SO.sub.3 removing agent at a supply unit on an upstream side of the precipitator; and a wet state processing unit between the air preheater and the supply unit to supply water to a flue gas to be made into a wet state; the wet state processing unit having a stand-up portion, a partition unit and a droplet supply unit.