RU2216514C2 - Method of ammonia production - Google Patents

Abstract

FIELD: ammonia production. SUBSTANCE: method of ammonia production from hydrocarbon materials, steam and air includes compression and purification of hydrocarbon materials from sulfur compounds, steam and steam-air catalytic conversion of methane, conversion of carbon monoxide, cleaning of produced nitrogen-hydrogen mixture from oxygen-containing compounds, compression, synthesis of ammonia in closed cycle. In so doing, added to initial air is nitrogen and obtained mixture is directed for steam-air catalytic conversion of methane, with ratio of added nitrogen and air equaling 0.001-1.121. EFFECT: reduced specific consumption of hydrocarbon materials. 2 ex

Description

 The invention relates to the production of ammonia and can be used in the chemical industry.

 A known method of producing ammonia from hydrocarbon raw materials, water vapor, air, oxygen, including purification of raw materials from sulfur compounds, steam-oxygen-catalytic conversion of methane in a shaft converter, conversion of carbon monoxide, purification of the obtained nitrogen-hydrogen mixture from oxygen-containing compounds, compression and synthesis of ammonia in a closed cycle [1].

 The method requires the consumption of technical oxygen for the conversion of methane. The closest in technical essence and the achieved result to the described invention is a method for producing ammonia from hydrocarbon raw materials, water vapor, air, including compression and purification of raw materials from sulfur compounds, steam and steam-air catalytic conversion of methane, conversion of carbon monoxide, purification of the obtained nitrogen-hydrogen mixture from oxygen-containing compounds, compression and synthesis of ammonia in a closed cycle [2].

This method is characterized by a high specific consumption of hydrocarbon feeds due to the supply of atmospheric oxygen methane to the steam-air conversion in a volume greater than is required. Oxygen binds to hydrogen and is then removed from the system in the form of water. It is impossible to supply oxygen less, since the amount of air oxygen supplied to the steam-air conversion of methane depends on the stoichiometric ratio between the main components of the gas mixture, which should be (Н ₂ + CO) / N ₂ = 3.0 ... 3.04.

 The objective of the invention is to reduce the specific consumption of hydrocarbons.

 This object is achieved in that in a method for producing ammonia from hydrocarbon feedstocks, water vapor, including compression and purification of feedstock from sulfur compounds, steam and steam-air catalytic conversion of methane, conversion of carbon monoxide, purification of the obtained nitrogen-hydrogen mixture from oxygen-containing compounds, compression and synthesis of ammonia in a closed cycle, according to the invention, nitrogen is added to the air and this mixture is sent to the steam-air catalytic conversion of methane.

 The amount of nitrogen added is equal to 0.001-1.121 of the amount of air sent to the steam-air catalytic conversion of methane.

 The invention is illustrated by the following examples.

 Example 1

Unit power 57.95 t / h. Ammonia is obtained from hydrocarbon raw materials, water vapor and air taken from the atmosphere and cleaned from dust, which compress, clean the raw materials from sulfur compounds on the catalyst at a temperature of 400 ^o C, conduct steam at a temperature of 760-825 ^o C and steam-air catalytic conversion of methane at the temperature at the outlet is 990-1002 ^o C, purification of the obtained nitrogen-hydrogen mixture from oxygen-containing compounds is compressed and ammonia synthesis is carried out in a closed cycle. 50.37 nm ³ / h of nitrogen (0.001 of the amount of air) is added to air in an amount of 50375 nm ³ / h (0.001 of the amount of air) and this mixture is sent to steam-air catalytic conversion of methane. The specific consumption of hydrocarbons is reduced by 0.0002% (the calculation was made using the equation of "quasi-direct transition" [3]).

 Example 2

The initial data in example 2 are the same as in example 1, except that to the air in the amount of 20653.75 nm ³ / h add 23152.8 nm ³ / h of nitrogen (1.121 of the amount of air) and this mixture is directed to vapor-air catalytic conversion of methane. The specific consumption of hydrocarbon raw materials is reduced by 5.7% (the calculation was determined using the equation of "quasi-direct transition" [3]).

When the amount of air is 20653.75 nm ³ / h, the heat obtained as a result of exothermic reactions is equal to the amount of heat consumed by endothermic reactions during the steam-air conversion of methane, that is, an increase in the amount of nitrogen above the specified boundary is impractical.

 It can be seen from the above examples that when using a mixture of air with nitrogen at the stage of steam-air catalytic conversion, the hydrocarbon consumption decreases by more than 5%, which gives a significant positive result for large volumes of raw material use.

 Examples show that beyond the specified boundaries of 0.001-1.121 it is impossible to achieve a tangible economic effect. At a value less than 0.001, the effect is small due to values approaching zero, and at values higher than 1.121, it will be impossible to conduct steam-air catalytic conversion of methane, since there will not be enough heat to carry out endothermic reactions.

Sources of information
1. Directory of nitrogen. T.1. - M., 1967, p. 95-98, 211, 366.

 2. Directory of nitrogen. - M .: Chemistry, 1986, p. 83-85, 213, 222, 360-364.

 3. Leites I. L., Sosna M.Kh., Semenov V.P. Theory and practice of chemical energy technology. - M .: Chemistry, 1988, p. 165 and 166.

Claims (1)

 A method of producing ammonia from hydrocarbon feedstocks, water vapor, air, including compressing and purifying the feedstock from sulfur compounds, steam and steam-air catalytic conversion of methane, converting carbon monoxide, purification of the obtained nitrogen-hydrogen mixture from oxygen-containing compounds, compression and synthesis of ammonia in a closed cycle, characterized in that nitrogen is added to the air in the amount necessary to obtain a mixture with a ratio of nitrogen: air = 0.001-1.121 and this mixture is sent to a steam-air catalytic convoy UIS methane.