Method for operating an ammonia plant, and plant for producing ammonia

A process for operating an ammonia plant, comprising:

• conveying a gas mixture, comprising nitrogen (N2), hydrogen (H2), and ammonia (NH3), cyclically in a synthesis circuit with a conveying device, wherein the conveying device comprises at least a first compressor having a first suction side and a first pressure side, wherein a first bypass line is provided from the first pressure side to the first suction side,
• converting nitrogen (N2) and hydrogen (H2) at least partly into ammonia (NH3) in a converter,
• cooling the gas mixture in a cooling device in such a way that ammonia (NH3) condenses out of the gas mixture,
• providing hydrogen at least partly by electrolysis,
• keeping at least a pressure in the synthesis circuit approximately constant, by a master controller, via at least one control loop on the basis of an anticipated amount of hydrogen,
• dictating, by the master controller, a minimum opening of a first flow control valve as a function of an anticipated first suction stream at the first suction side of the first compressor, wherein the first flow control valve establishes at least a flow rate in the first bypass line, and
• dividing the gas mixture upstream of the cooling device into a first substream and a second substream, wherein the first substream is passed through the cooling device, wherein the second substream is introduced back into the synthesis circuit in a region upstream of the first suction side of the first compressor of the conveying device, and wherein the second substream is cooled before introduction into the synthesis circuit, wherein the master controller dictates the minimum opening of a second flow control valve, wherein the second flow control valve establishes at least a flow rate of the second substream.

A plant for producing ammonia (NH3) in a synthesis circuit, comprising:

• at least one conveying device for cyclically conveying a gas mixture comprising nitrogen (N2), hydrogen (H2), and ammonia (NH3),
• at least one converter, wherein nitrogen (N2) and hydrogen (H2) can be converted at least partly into ammonia (NH3) in the converter, and
• at least one cooling device in which the gas mixture can be cooled in such a way that ammonia (NH3) condenses out of the gas mixture,
• wherein hydrogen can be provided at least partly by an electrolyzer,
• wherein at least one bypass line is provided to circumvent at least one unit of the synthesis circuit,
• wherein a flow rate in the bypass line can be established by at least one flow control valve,
• wherein a master controller is provided, wherein the at least one flow control valve can be regulated by the master controller.