Provided is a method for separating ammonia gas using zeolite membrane having excellent separation stability at a high temperature capable of separating ammonia gas from a mixed gas composed of multiple components including ammonia gas, hydrogen gas, and nitrogen gas to the permeation side with high selectivity and high permeability. Also provided is a method for separating ammonia by selectively permeating ammonia gas from a mixed gas containing at least ammonia gas, hydrogen gas, and nitrogen gas using a zeolite membrane, wherein the ammonia gas concentration in the mixed gas is 1.0% by volume or more.

A high-concentration ammonia production method includes: synthesizing ammonia through electrolysis using water and nitrogen as raw materials; subjecting a resultant generation gas to treatment using an ammonia separation membrane or an ammonia PSA to separate the generation gas into high-concentration ammonia and a residual gas; recycling the residual gas as a nitrogen gas raw material of an ammonia synthesis reactor, and liquefying the high-concentration ammonia recovered through the ammonia separation membrane or the ammonia PSA; and subjecting an unliquefied gas separated from liquefied ammonia to the treatment using the ammonia separation membrane or the ammonia PSA again. According to the present disclosure, ammonia is synthesized by adopting an electrolysis method in which the synthesized ammonia substantially does not contain hydrogen, in combination with ammonia separation and recovery treatment using membrane separation or PSA. With this, high-concentration ammonia can be synthesized and recovered with high efficiency through an entire process.

A high-concentration ammonia production method includes: synthesizing ammonia through electrolysis using water and nitrogen as raw materials; subjecting a resultant generation gas to treatment using an ammonia separation membrane or an ammonia PSA to separate the generation gas into high-concentration ammonia and a residual gas; recycling the residual gas as a nitrogen gas raw material of an ammonia synthesis reactor, and liquefying the high-concentration ammonia recovered through the ammonia separation membrane or the ammonia PSA; and subjecting an unliquefied gas separated from liquefied ammonia to the treatment using the ammonia separation membrane or the ammonia PSA again. According to the present disclosure, ammonia is synthesized by adopting an electrolysis method in which the synthesized ammonia substantially does not contain hydrogen, in combination with ammonia separation and recovery treatment using membrane separation or PSA. With this, high-concentration ammonia can be synthesized and recovered with high efficiency through an entire process.

The present invention relates to processes and systems for basic gas, e.g., ammonia, recovery and/or acid-gas separation. In some embodiments, a system for acid gas separation may be integrated with an ammonia abatement cycle employing a high temperature absorber. In some embodiments, a system for acid gas separation may employ a higher temperature absorber due to the lower energy consumption and cost of the integrated ammonia abatement cycle. Advantageously, heat may be recovered from the absorber to power at least a portion of any acid gas desorption in the process. Reverse osmosis or other membranes may be employed.

The present invention relates to processes and systems for basic gas, e.g., ammonia, recovery and/or acid-gas separation. In some embodiments, a system for acid gas separation may be integrated with an ammonia abatement cycle employing a high temperature absorber. In some embodiments, a system for acid gas separation may employ a higher temperature absorber due to the lower energy consumption and cost of the integrated ammonia abatement cycle. Advantageously, heat may be recovered from the absorber to power at least a portion of any acid gas desorption in the process. Reverse osmosis or other membranes may be employed.

The disclosed technology includes a method for producing ultrafine alumina from salt slag waste generated in aluminum recycling useful in the manufacture of durable ceramic products; a system for recovering alumina from salt slag waste; a method and systems for recovering salts, aluminum and alumina from salt slag waste; and a method and systems of capturing ammonia in a process recovering salts, aluminum and alumina from salt slag waste. The methods and systems provided crush the dry particles of the salt slag waste, scrub the slag with water, and with steam and by means of a vented alumina press, dewater the scrubbed slag particles. In some methods and systems of the disclosed technology, the particles of the pressed alumina cake are further reduced. In some methods and systems, the salt in the salt effluent is crystalized. In some methods and systems of the disclosed technology, the ammonia is contained and captured.

The disclosed technology includes a method for producing ultrafine alumina from salt slag waste generated in aluminum recycling useful in the manufacture of durable ceramic products; a system for recovering alumina from salt slag waste; a method and systems for recovering salts, aluminum and alumina from salt slag waste; and a method and systems of capturing ammonia in a process recovering salts, aluminum and alumina from salt slag waste. The methods and systems provided crush the dry particles of the salt slag waste, scrub the slag with water, and with steam and by means of a vented alumina press, dewater the scrubbed slag particles. In some methods and systems of the disclosed technology, the particles of the pressed alumina cake are further reduced. In some methods and systems, the salt in the salt effluent is crystalized. In some methods and systems of the disclosed technology, the ammonia is contained and captured.

Systems and methods are disclosed in which ammonia may be recovered efficiently from wastewater through the application of the mass-transfer reaction kinetic model. The recovery process may involve the stripping of NH.sub.3 from wastewater by aeration and the absorption of this stripped NH.sub.3 gas into a recovery solution by utilizing stoichiometric acid-base reactions and the operating parameters optimized by the model which facilitate both processes. Another step may be performed in which saturated solution comprising the recovered NH.sub.3 may be further evaporated and liquefy to produce a pure bioammonia product. Applying the mass-transfer reaction kinetic to the recovery can not only enhance the NH.sub.3 removal and recovery yield but also increase the NH.sub.3 removal and recovery rate. Numerous operating parameters can be adjusted to maximize the recovery yield and recovery rate.

Systems and methods are disclosed in which ammonia may be recovered efficiently from wastewater through the application of the mass-transfer reaction kinetic model. The recovery process may involve the stripping of NH.sub.3 from wastewater by aeration and the absorption of this stripped NH.sub.3 gas into a recovery solution by utilizing stoichiometric acid-base reactions and the operating parameters optimized by the model which facilitate both processes. Another step may be performed in which saturated solution comprising the recovered NH.sub.3 may be further evaporated and liquefy to produce a pure bioammonia product. Applying the mass-transfer reaction kinetic to the recovery can not only enhance the NH.sub.3 removal and recovery yield but also increase the NH.sub.3 removal and recovery rate. Numerous operating parameters can be adjusted to maximize the recovery yield and recovery rate.

A process and system for removing ammonia from ammonia-containing purge gas of a urea plant, the process comprising: contacting said ammonia-containing purge gas with carbon dioxide at a low temperature, reaction of ammonia to form crystals of ammonium salts in a multiphase stream, and removal of the solid ammonium salts from the multiphase stream.