Abstract: Described herein is an apparatus for the synthesis of ammonia from a synthesis gas containing N2 and H2, comprising at least one first reactor. The apparatus comprises a first non-cooled catalyst bed unit, at least one heat exchanger apparatus, and at least two cooled catalyst bed units. Each cooled catalyst bed unit is equipped with a plurality of cooling pipes. The apparatus further comprises a circuit line having at least one feed apparatus and at least one outlet apparatus, wherein the circuit line, starting from the feed apparatus, comprises in consecutive downstream arrangement the plurality of cooling pipes, the first non-cooled catalyst bed unit, the at least one heat exchanger apparatus, and the at least two cooled catalyst bed units up to the outlet apparatus.

Abstract: Disclosed herein is a process and a plant for recovering ammonia from a mixture including ammonia, acid gas containing H2S and/or CO2 and low-boiling water-soluble organic components. To avoid an enrichment of volatile organic compounds in the acid gas absorber, a partial stream of the liquid phase is withdrawn from an acid gas absorber and processed such that gaseous ammonia with a reduced content of volatile organic components is obtained, which is recirculated into the acid gas absorber.

Abstract: Described herein is an apparatus for the synthesis of ammonia from a synthesis gas containing N2 and H2, comprising at least one first reactor. The apparatus comprises a first non-cooled catalyst bed unit, at least one heat exchanger apparatus, and at least two cooled catalyst bed units. Each cooled catalyst bed unit is equipped with a plurality of cooling pipes. The apparatus further comprises a circuit line having at least one feed apparatus and at least one outlet apparatus, wherein the circuit line, starting from the feed apparatus, comprises in consecutive downstream arrangement the plurality of cooling pipes, the first non-cooled catalyst bed unit, the at least one heat exchanger apparatus, and the at least two cooled catalyst bed units up to the outlet apparatus.

Abstract: Disclosed herein is a process and a plant for recovering ammonia from a mixture including ammonia, acid gas containing H2S and/or CO2 and low-boiling water-soluble organic components. To avoid an enrichment of volatile organic compounds in the acid gas absorber, a partial stream of the liquid phase is withdrawn from an acid gas absorber and processed such that gaseous ammonia with a reduced content of volatile organic components is obtained, which is recirculated into the acid gas absorber.

Abstract: Ammonia is produced from a synthesis gas containing nitrogen and hydrogen on a granular catalyst in at least one reactor at pressures in the range from 50 to 300 bar and temperatures in the range from 100 to 600° C. A product mixture containing NH3 vapor is withdrawn from the reactor, is cooled, and ammonia is condensed and separated. There is obtained a recycle gas to which fresh synthesis gas is admixed, the recycle gas being recirculated to the reactor as synthesis gas. Unreacted synthesis gas is passed through a first catalyst bed free of cooling tubes and subsequently as partly reacted synthesis gas with an NH3 content of 5 to 20 vol-% as heating fluid through a heat exchanger. Partly reacted synthesis gas is passed through at least one further catalyst bed, through which extend cooling tubes. Unreacted synthesis gas is passed as cooling gas through the cooling tubes of the further catalyst bed, and cooling gas heated to 300 to 500° C. is introduced into the first catalyst bed.

Abstract: Ammonia is produced from a synthesis gas containing nitrogen and hydrogen on a granular catalyst in at least one reactor at pressures in the range from 50 to 300 bar and temperatures in the range from 100 to 600° C. A product mixture containing NH3 vapor is withdrawn from the reactor, is cooled, and ammonia is condensed and separated. There is obtained a recycle gas to which fresh synthesis gas is admixed, the recycle gas being recirculated to the reactor as synthesis gas. Unreacted synthesis gas is passed through a first catalyst bed free of cooling tubes and subsequently as partly reacted synthesis gas with an NH3 content of 5 to 20 vol-% as heating fluid through a heat exchanger. Partly reacted synthesis gas is passed through at least one further catalyst bed, through which extend cooling tubes. Unreacted synthesis gas is passed as cooling gas through the cooling tubes of the further catalyst bed, and cooling gas heated to 300 to 500° C. is introduced into the first catalyst bed.

Abstract: Ammonia is recovered from waste water containing NH3, at least one acid gas (CO2, H2S) and inert gases. Firstly, the waste water is passed through a pretreatment column and then, at least in part, into a total stripping column. The top product from the total stripping column is cooled in a condenser, and an aqueous NH3-containing condensate coming from the condenser is fed to an NH3 stripping column. The top product from the NH3 stripping column is brought into direct contact with circulating aqueous NH3-containing condensate in a wash column, and NH3 is recovered from the top product from the wash column. Some of the bottom product from the wash column is fed back into the NH3 stripping column. The temperature in the bottom region of the pretreatment column is set to from less than 30 to 200° C., a sub-stream of the waste water is introduced into the upper region of the pretreatment column, and a second sub-stream of the waste water is fed into the pretreatment column below the first sub-stream.

Abstract: Phenols are extracted from a phenol-containing waste water by means of two solvents A and B. The waste water is first of all passed through a first extraction zone, and then through a second extraction zone. To the first extraction zone a mixture of the solvents A and B is supplied, and into the second extraction zone at least one of the two solvents is introduced. From the first extraction zone, solvent-mixture loaded with phenols is withdrawn, phenols am separated therefrom, and the solvents are used again in at least one of the extraction zones. Solvent B is lower-boiling and has a lower water solubility at a temperature in the range from 10.degree. to 60.degree. C. than solvent A. Solvent B has a water solubility at 40.degree. C. of up to 2 wt.-% and a boiling point at 1 bar of 50.degree. to 100.degree. C., and it is miscible with solvent A. Solvent A has a boiling point at 1 bar of not more than 172.degree. C. and a water solubility at 40.degree. C. of not more than 5 wt.-%.

Abstract: The ammonium polysulfide is produced in at least one electrochemical cell, to which an aqueous ammonium sulfide solution is supplied as electrolyte. The cell comprises an anode, a gas diffusion cathode, and between the anode and the cathode an electrolyte chamber, where the cell voltage is 0.01 to 5V. The cathode has an electrically conductive, gas-permeable carbon layer, over which flows gas containing free oxygen, and which is in contact with the electrolyte. O.sub.2 -containing gas is introduced into the electrolyte chamber, thereby forming hydroperoxide anions (OOH.sup.-) in the electrolyte chamber. From the electrolyte chamber a solution containing ammonium polysulfide and a residual gas are withdrawn.

Abstract: An aqueous solution which contains ammonium polysulfide is proportionally added to the sour water, which contains cyanide ions, ammonium ions, and sulfide ions. At least part of the cyanide ions contained in the sour water is converted to thiocyanate ions by the ammonium polysulfide. The solution which contains ammonium polysulfide is prepared from an aqueous solution by oxidation in an electrochemical cell. That aqueous solution may consist entirely or in part of sour water.

Abstract: An aqueous effluent is supplied to a stripping column (total stripping column) from which a mixture that is rich in NH.sub.3, CO.sub.2 and H.sub.2 S is withdrawn as a head product. In at least one additional stripping column the mixture is separated into a mixture which is rich in NH.sub.3 and a mixture which is rich in the sour gaes CO.sub.2 and H.sub.2 S. The mixture which is rich in NH.sub.3 is scrubbed with liquid ammonia. The overhead product from the total stripping column is cooled in a condenser under a pressure of 1 to 7 bars and is thus transformed into a liquid phase to such an extent that the liquid phase contains 70 to 100% of the NH.sub.3 which has been supplied to the condenser. The liquid phase is supplied at a temperature of 30.degree. to 90.degree. C. to a second stripping column (NH.sub.3 stripping column), which is operated under a pressure of 1 to 4 bars and from which a gas mixture that is rich in NH.sub.3 is withdrawn as a head product.