A method for recovering carbon dioxide by absorbing carbon dioxide present in a combustion exhaust gas using an aqueous alkanolamine solution, comprising the step of bringing a combustion exhaust gas from which carbon dioxide has been absorbed and removed into contact with water containing carbon dioxide. A method for treating a combustion exhaust gas for denitration using ammonia as a reducing agent and for removal of carbon dioxide by absorption with an aqueous alkanolamine solution, which method comprising the steps of recovering ammonia present in the combustion exhaust gas after the carbon dioxide removal, and using the recovered ammonia as a reducing agent for the denitration. A method for removing CO₂ from a combustion exhaust gas comprising the step of bringing the combustion exhaust gas into contact under atmospheric pressure with an aqueous monoethanolamine solution having a concentration of 35% by weight or more.

Method for treating combustion exhaust gas

A process is described that removes by oxidation the excess ammonia (NH3) gas from flue gases that have been subjected to selective catalytic reduction (SCR) of oxides of nitrogen (NOx) by ammonia injection. The inventive process incorporates a secondary catalyst of precious metal and vanadia on a metal oxide such as titania to catalyze the oxidation of both ammonia and carbon monoxide (CO) while maintaining sulfur dioxide (SO2) levels.

Ammonia oxidation catalyst for the coal fired utilities

An injection lance (10) for injecting a mixture of air and anhydrous ammonia into a boiler (12) having a flue gas stream moving therethrough to reduce nitrogen oxides therein. The lance (10) comprises outer (18), intermediate (42), and inner tubes (28). The outer end (30) of the inner tube (28) is in communication with a source of anhydrous ammonia while the outer end (22) of the outer tube (18) is in communication with a source of mixing air. The outer end (44) of the intermediate tube (42) sealably embraces the exterior surface (36) of the inner tube (28) so that air being introduced into the outer tube (28) passes towards the inner end (32) of the lance (10) between the outer (18) and intermediate (42) tubes. The mixing air and the anhydrous ammonia are passed into the space between the inner tube (28) and the intermediate tube (42) and then are discharged from the lance (10) through discharge nozzles (54) or ports which extend from the interior of the intermediate tube (42) to the exterior of the outer tube (18).

An injection lance for uniformly injecting anhydrous ammonia and air into a boiler cavity

The invention relates to a method for the manufacturing of a composite metal product. More particularly, the invention relates to a method for the manufacturing of a composite product consisting of at least two stainless steel materials having different chemical compositions, particularly a composite stainless product on which decorative patterns can or have been produced by etching. It is significant feature of the invention that at least two stainless steel materials having different chemical compositions are bonded together through hot isostatic compaction at a pressure exceeding 600 bar and a temperature exceeding 1000 °C, at least one of said materials consisting of powder, for the achievement of a consolidated body.

Method relating to the manufacturing of a composite metal product

In the selective reduction of nitrogen oxides of flue gases with ammonia, the ammonia is added as ammonia water upstream of the reduction zone. Residual gas phase ammonia and ammonia compounds collected with the flyash serve as recycled ammonia sources and ammonia is formed from them and, in an ammoniacal solution, is added to the ammonia water supply vessel.

Method of removing nitrogen oxides from a flue gas stream

Process and apparatus wherein nitrogen oxides NOx contained in waste gases produced by combustion of fossil fuels in a firing plant are removed by reacting the waste gases with ammonia NH3 to reduce the nitrogen oxides to elementary nitrogen N2 ; subjecting the waste gases after being so reacted to wet waste gas cleaning whereby the washing water removes the unreacted ammonia (slip) from the waste gas to produce slip enriched washing water; raising the pH value of the slip enriched washing water to a value of more than 10, introducing air into the pH raised slip enriched washing water to remove the slip from the water and produce an air-slip mixture and recycling the slip into the furnace to react with waste gases to lower the amount of ammonia discharged into the atmosphere.

Process and installation for the recovery of ammonia during the separation of nitrogen oxide from waste gases

In a firing installation with a furnace (1) and a boiler (2), ammonia NH3 is admixed to the flue gas stream, whereby the nitrogen oxides are reduced in a reaction chamber (5) with catalysts. In a flue gas wet-scrubbing unit (7) downstream of the reaction chamber (5), the unreacted ammonia is dissolved in the scrubbing water. The latter is passed through a connection line (8) into a stripping column (9), where the ammonia is stripped from the scrubbing water and mixed with introduced air. This air enriched with ammonia NH3 is passed as combustion air into the furnace (1). As a result, the nitrogen oxide reduction can be operated with a large ammonia excess, so that a degree of nitrogen oxide separation of any desired high level can be achieved. In addition, the ammonia stripped out in the stripping column (9) is passed to the combustion, where it reacts with the NOx present, whereby the ammonia consumption is substantially reduced. This can also be achieved in combination with the SNCR process. … …

Hans Rueegg

Papers

Process and installation for the recovery of ammonia during the separation of nitrogen oxide from waste gases

Process and plant for the recuperation of ammoniac by separating nitrogen oxides from flue gases