A method for the control of nitrogen oxides content in the combustion fumes of a thermal power plant is disclosed; the method comprises the on-site production of ammonia by the steps of: electrolysis of water as a source of hydrogen; separation of air as a source of nitrogen, formation of a make-up gas and synthesis of ammonia in a suitable synthesis loop; said on-site produced ammonia, or a solution thereof, is used for a process of reduction of nitrogen oxides in the combustion fumes.

A process for producing ammonia and a derivative of ammonia from a natural gas feed comprising conversion of natural gas into a make-up synthesis gas; synthesis of ammonia; use of said ammonia to produce said derivative of ammonia, wherein a portion of the natural gas feed is used to fuel a gas engine; power produced by said gas engine; is transferred to at least one power user of the process, such as a compressor; heat is re-covered from exhaust gas of said gas engine;, and at least part of said heat may be recovered as low-grade heat available at a temperature not greater than 200° C., to provide process heating to at least one thermal user of the process, such as CO2 removal unit or absorption chiller; a corresponding plant and method of modernization are also disclosed.

Included are an ammonia synthesis column that synthesizes ammonia from a raw material gas, a discharge line that discharges a synthetic gas, a water-cooled cooler that cools the synthetic gas with a coolant, disposed in the discharge line, an ammonia separator into which a synthetic gas after cooling is introduced and which separates the ammonia gas and a liquid ammonia from each other, a raw material return line that returns a raw material gas containing the separated ammonia gas to the ammonia synthesis column side as a return raw material gas, and a compressor that compresses the return raw material gas, disposed in the raw material return line. An ammonia concentration in the return raw material gas is 5 mol % or more, and an ammonia synthesis catalyst that synthesizes the ammonia gas in the ammonia synthesis column is a ruthenium catalyst.

Parallel co-production process for the production of methanol and urea product from a hydrocarbon containing feed-stock by means of autothermal reforming, intermediary methanol and ammonia formation and conversion of the ammonia to urea product and catalytic oxidation of the methanol to formaldehyde.

The invention provides a perovskite-type oxynitride hydride which can be easily synthesized by achieving both improvement in catalytic performance and stabilization when used as a support of a catalyst. The oxynitride hydride is represented by general formula (1a) or (1b).

ABO.sub.3-xN.sub.yH.sub.z  (1a)

AB.sub.2O.sub.4-xN.sub.yH.sub.z  (1b)

(In the above general formulas (1 a) and (1 b), A is at least one selected from the group consisting of Ba and Sr; B is at least one selected from the group consisting of Ce, La and Y; x represents a number represented by 0.2≤x≤2.0; y represents a number represented by 0.1≤y≤1.0; and z represents a number represented by 0.1≤z≤1.0.)

In one embodiment, an ammonia synthesis system comprising, an ammonia synthesis reactor, a waste heat boiler, a supply water heat exchanger, a recycle gas heat exchanger, a water cooler, an ammonia chiller and refrigeration exchanger, a secondary ammonia chiller, an ammonia separator, a liquid ammonia tank, a recycle compressor and a start-up heater, and wherein, a process gas is heated in the recycle gas heat exchanger and enters the ammonia synthesis reactor and the waste heat boiler, a reacted gas stream exits from a bottom of the waste heat boiler and is cooled in the supply water heat exchanger, a gas stream enters the recycle gas heat exchanger, the water cooler, the ammonia chiller and refrigeration exchanger, the secondary ammonia chiller, and is cooled, the gas stream enters the ammonia separator to form a separate liquid ammonia and the separated liquid ammonia enters the liquid ammonia tank.

A pulse jet system and method is disclosed. In an example, the pulse jet system includes a combustion chamber, intake ports to deliver combustion agents to the combustion chamber, an expansion chamber to cool a combustion product following combustion of the combustion agents in the combustion chamber, and an exhaust to exit the cooled gas from the expansion chamber. In another example, the pulse jet system includes a combustion chamber with intake ports to deliver combustion agents to the combustion chamber, wherein the combustion chamber is part of a four cycle engine. The pulse jet system also includes an expansion chamber to cool a combustion product following combustion of the combustion agents in the combustion chamber.

A pulse jet system and method is disclosed. In an example, the pulse jet system includes a combustion chamber, intake ports to deliver combustion agents to the combustion chamber, an expansion chamber to cool a combustion product following combustion of the combustion agents in the combustion chamber, and an exhaust to exit the cooled gas from the expansion chamber. In another example, the pulse jet system includes a combustion chamber with intake ports to deliver combustion agents to the combustion chamber, wherein the combustion chamber is part of a four cycle engine. The pulse jet system also includes an expansion chamber to cool a combustion product following combustion of the combustion agents in the combustion chamber.

Reactor for catalytic chemical reactions comprising a catalyst bed with an annular-cylindrical form crossed by a radial flow or mixed axial-radial flow, wherein the bed is delimited by cylindrical walls made gas-permeable by means of slits and the catalyst bed is formed by particles of catalyst with a nominal minimum size such that: the ratio between a transverse dimension of the slits and the nominal minimum size of the particles of catalyst is smaller than or equal to 0.6; the catalyst bed contains no more than 3% by weight of particles with an actual size smaller than said nominal size.

A method for preparing a silicate/carbon composite from attapulgite, and use of the silicate/carbon composite are disclosed. The preparation method includes: (1) with attapulgite as a raw material, preparing SiO.sub.2 with a special structure; (2) dispersing the prepared SiO.sub.2 in water to obtain a suspension, and subjecting the suspension to ultrasonic dispersion; dissolving a metal nitrate in the suspension, adding NH.sub.4Cl, and adding ammonia water dropwise to the suspension; and adding sucrose to obtain a suspension; (3) subjecting the suspension to microwave hydrothermal reaction; after the reaction is completed, centrifuging a resulting system; and separating a resulting solid; and (4) subjecting the solid to high-temperature calcination in a muffle furnace, and grinding a resulting product to obtain the silicate/carbon composite, which can be used in photocatalytic ammonia synthesis.