Disclosed is a technology based upon the nesting of tubes to provide chemical reactors or chemical reactors with built in heat exchanger. As a chemical reactor, the technology provides the ability to manage the temperature within a process flow for improved performance, control the location of reactions for corrosion control, or implement multiple process steps within the same piece of equipment. As a chemical reactor with built in heat exchanger, the technology can provide large surface areas per unit volume and large heat transfer coefficients. The technology can recover the thermal energy from the product flow to heat the reactant flow to the reactant temperature, significantly reducing the energy needs for accomplishment of a process.

A method for catalytic ammonia synthesis under concentrated solar energy and related catalysts. The method includes placing a catalyst in a reaction apparatus, feeding nitrogen and hydrogen into the reaction apparatus, and controlling a surface temperature of the catalyst to reach about 300 C. to 550 C. under irradiation of concentrated sunshine, to synthesize ammonia. The catalyst includes an amorphous and electron-rich black nano TiO.sub.2-z (0<z<2) with a disordered surface serves as a carrier material, and an elemental nano-crystal of Fe or Ru serves as an active ingredient. The active ingredient is loaded on the carrier material. Sunshine is used as the energy during ammonia synthesis reaction, and light in the whole wave band can be utilized sufficiently. Ammonia can be synthesized under solar energy with a high efficiency, and no fossil energy or electrical energy is needed. A synergetic catalytic effect of optical energy and thermal energy can be obtained.

The disclosure pertains to a plant for the production of ammonia. The ammonia is produced from hydrogen obtained by electrolysis of water. The electrolysis is powered by a renewable source of energy, complemented with power obtained from the plant during periods of low or no availability of the renewable energy. To this end, the plant is configured such that it can be operated in a charge configuration (obtaining and storing power) and a discharge configuration (employing said power).

A method and an apparatus for producing ammonia, in which a first hydrogen/nitrogen fraction is provided at a time-varying flow rate in order to form an ammonia synthesis gas which is converted to ammonia in an ammonia synthesis, wherein the first hydrogen/nitrogen fraction is supplemented by a second hydrogen/nitrogen fraction in such a way that, during normal operation, the ammonia synthesis gas can always be supplied to the ammonia synthesis at a flow rate which exceeds a predefined minimum value. The characterizing feature is that ammonia produced in the ammonia synthesis is transferred in liquid form to a storage means from which ammonia is taken and split into hydrogen and nitrogen in order to obtain hydrogen and nitrogen so as to form the second hydrogen/nitrogen fraction.

In a process for operating an ammonia plant, a gas mixture comprising nitrogen, hydrogen and ammonia is conveyed cyclically in a synthesis circuit with a conveying device which comprises at least a first compressor, nitrogen and hydrogen are converted at least partly into ammonia in a converter, the gas mixture is cooled in a cooling device in such a way that ammonia condenses out of the gas mixture, and hydrogen is provided at least partly by electrolysis. In this process, the utilization of fluctuating renewable energies can be integrated into existing plant designs, for the provision of hydrogen; for this reason, a master controller is provided and the master controller keeps at least the pressure in the synthesis circuit approximately constant via at least one control loop, on the basis of the anticipated amount of hydrogen. For this, the apparatus comprises a first bypass line for circumventing the first compressor, and a second bypass line for circumventing the cooling device.

Method for controlling an ammonia plant, wherein the ammonia plant comprises an ammonia synthesis section with an ammonia converter and a hydrogen generation section connected to a hydrogen storage tank, the method includes controlling the amount of hydrogen stored or delivered to the ammonia synthesis section to maintain target ranges of: the amount of hydrogen contained in the hydrogen tank; the flow rate of hydrogen delivered to the ammonia synthesis section; the flow rate of feed gas fed to said ammonia converter.

An apparatus and method for production of green ammonia using a heat exchanger unit controls a compressor unit to increase a first pressure value of a first set of reactants to a second pressure value, and a set of heat exchanger units to increase temperature of a second set of reactants to a second temperature value using heat generated during production of green ammonia in the reactor. The apparatus also controls a reactor unit to produce green ammonia at a first timestamp and at a second timestamp based upon a chemical reaction between the reactants of the corresponding first and second set of reactants. The second set of reactants are fed into the reactor unit at the second pressure value and a third temperature value. The apparatus also controls a storage unit to store green ammonia produced at the first and second timestamps.

A method of producing ammonia includes heating, with a start-up oven, a first synthesis gas for a first ammonia synthesis in a first reactor; transferring the heated first synthesis gas to the first reactor for initiating a chemical reaction; heating, with the start-up oven, a second synthesis gas for a second ammonia synthesis in a second reactor; and transferring the heated second synthesis gas to the second reactor for initiating a chemical reaction, wherein a high-pressure synthesis of ammonia is carried out in the first reactor and a low-pressure synthesis of ammonia is carried out in the second reactor at a process pressure which is lower than the process pressure in the first reactor.

An apparatus and a method for production of green hydrogen using steam generated during the production of green ammonia controls: (i) a supply of steam from an ammonia reactor unit to a heat exchange unit at a first timestamp; (ii) the heat exchange unit to extract a pre-determined amount of heat from steam, and to transfer a pre-determined amount of heat to a water supply unit. The apparatus also controls the water supply unit to increase the water temperature from a first temperature value to a second temperature value using a transferred, pre-determined amount of heat. The apparatus also controls the water supply to an electrolyzer unit. The apparatus also controls the ammonia reactor unit to produce green ammonia and steam at a second timestamp using produced green hydrogen. The apparatus also controls an ammonia storage unit to store produced green ammonia at the first and second timestamps.

A method for revamping a front-end of an ammonia plant, said front-end comprising a reforming section (1, 2) with air-fired secondary reformer or autothermal reformer (2), a treatment section (3) of the effluent from said reforming section, and an air feed compressor (6), wherein an O.sub.2-containing stream (8) is directed to said reforming section (2) for use as oxidant, at least one nitrogen stream (9) is introduced at a suitable location of the front-end, to provide a desired molar ratio between hydrogen and nitrogen in the product gas, and at least part of said nitrogen stream (9) is compressed via said feed compressor (6).