A gas clean-up unit includes a first conversion unit configured to perform a first conversion process of converting hydrogen cyanide contained in gas to be treated to ammonia, in presence of a first catalyst and at a first predetermined temperature; a second conversion unit configured to perform a second conversion process of converting carbonyl sulfide in the gas that has been subjected to the first conversion process to hydrogen sulfide, in presence of a second catalyst and at a second predetermined temperature lower than the first predetermined temperature; a cleaning unit configured to perform a cleaning process of bringing the gas into gas-liquid contact with cleaning liquid to remove the ammonia by cleaning; and a desulfurization unit configured to absorb and remove hydrogen sulfide in the gas by bringing the gas that has been subjected to the cleaning process into gas-liquid contact with absorbent.

A system and a process for reducing greenhouse gas emissions are disclosed herein. The system may include a combustion zone, a catalytic converter, a methanation reactor, a compressor, a normal venting unit, a vacuum protection unit, and a control system. The process may include feeding a fuel, a methane-containing gas, and an oxygen-containing gas into a first reactor unit, and producing a combustion products stream comprising carbon monoxide, carbon dioxide, and water. The process may include cooling the combustion products stream via a cooling system, feeding the cooled exhaust stream and hydrogen to a second reactor unit. The second reactor unit may include a first catalyst for reacting oxygen with carbon monoxide to form carbon dioxide, and a second catalyst for reacting carbon dioxide with hydrogen to produce methane. The process may include recovering an effluent from the second reactor unit and feeding it to the first reactor unit.

Process for reducing the content of NOx and N2O from an input tail gas of a nitric acid process, said input tail gas having a temperature lower than 400 C., the process comprising an abatement stage at least including a deN2O stage and deNOx stage and providing a conditioned tail gas having a temperature greater than the input tail gas, wherein, prior to submission to said abatement stage, said input tail gas is pre-heated to a temperature of at least 400 C. by indirect heat exchange with at least a portion of said conditioned gas.

A gas treatment system includes a first scrubber configured to treat a gas exhausted from a process chamber, a catalytic reactor connected to the first scrubber and configured to treat a gas passing through the first scrubber, and a second scrubber connected to the catalytic reactor and configured to treat a gas passing through the catalytic reactor, where the catalytic reactor includes a fluidized bed reactor (FBR).

A flow-through solid catalyst formed by coating a zeolite material on a metal or ceramic solid substrate. In some embodiments, the solid substrate is formed as flat plates, corrugated plates, or honeycomb blocks.

The present invention relates generally to the field of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.) and, in particular to a new and useful method and apparatus for: (i) reducing halogen levels necessary to affect gas-phase mercury control; (ii) reducing or preventing the poisoning and/or contamination of an SCR catalyst; and/or (iii) controlling various emissions. In still another embodiment, the present invention relates to a method and apparatus for: (A) simultaneously reducing halogen levels necessary to affect gas-phase mercury control while achieving a reduction in the emission of mercury; and/or (B) reducing the amount of selenium contained in and/or emitted by one or more pieces of emission control equipment for boilers, heaters, kilns, or other flue gas-, or combustion gas-, generating devices (e.g., those located at power plants, processing plants, etc.).

An air pollution control system includes a denitration device that removes nitrogen oxide in flue gas from a boiler; a heat transfer tube for recovering part of heat of the flue gas after denitration; a precipitator that removes soot and dust in the flue gas after heat recovery; a desulfurization device that removes sulfur oxide in the flue gas discharged from the precipitator; a heat transfer tube for heating the flue gas discharged from the desulfurization device; a circulation pump that circulates a heat medium between the heat transfer tubes; a heat medium heater provided to the circulation pipe to heat the heat medium; and a control device that controls the heat medium heater based on an ammonia concentration at an outlet of the denitration device. The control device causes the heat medium heater to heat the heat medium when the ammonia concentration is higher than a certain value.

An object of the present invention is to provide a new frameless catalytic thermal oxidation device capable of treating concentrations of harmful materials including NOx at a low temperature. Further, another object of the present invention is to provide a frameless catalytic thermal oxidation device capable of minimizing the occurrence of THC and minimizing a risk of accidents and environmental pollution which may occur in maintenance operations. According to the objects, the present invention provides a cartridge-type thermal oxidation device capable of being separated for maintenance, wherein a cartridge internal structure is configured so that the time while the material to be treated stays in a zone with the catalyst is increased, and a member capable of dropping and collecting powder generated by thermal oxidation reaction is configured.

Provided is a renewable wet desulfurization process using a suspension bed, comprising mixing the 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 suspension bed 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 rich solution and a purified gas, subjecting the resulting rich solution to flash evaporation and then reacting with an oxygen-containing gas for carrying out regeneration. 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 present invention can achieve regeneration of a spent desulfurizer with a regeneration efficiency as high as 65%-83%, and the barren solution obtained by the regeneration may be recycled for being used as the desulfurization slurry, without generating secondary pollution, which is very suitable for industrial promotion.

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.