Method and converter to produce ammonia

 

The invention relates to the production of ammonia by the catalytic conversion of ammonia synthesis gas. The method of producing ammonia includes the steps of contacting the ammonia synthesis gas with a catalyst for ammonia synthesis, which is located in the form of the reaction zone in one or more catalytic tube, cooling the reaction zone with the enforcement of the way in isothermal conditions through the implementation of the circulation of the cooling agent inside the cooling tubes, each of which concentrically surrounds one catalytic tube, with a cooling agent selected from the group comprising salt, a mixture of salts and metals having a melting temperature below the temperature in the reaction zone and the withdrawal of enriched ammonia flow resulting from the reaction zone. The Converter includes at least one catalytic tube, adapted to receive the ammonia synthesis gas and holding the reaction zone of the catalyst for ammonia synthesis, and at least one cooling tube which concentrically surrounds the at least one catalytic tube and in which a cooling agent selected from the group comprising salt, a mixture of salts and metals having a melting temperature below t the s ongoing way in isothermal conditions. 2 s and 5 C. p. F.-ly, 3 ill., table 1.

The invention relates to the production of ammonia by the catalytic conversion of ammonia synthesis gas. More specifically, this invention relates to the synthesis of ammonia at high speeds the conversion of ammonia synthesis gas in the presence of a catalyst for the synthesis of ammonia, which is located in the tubular reaction zone, cooled by the refrigerant in winetroube region of the tubular reaction zone. The synthesis of ammonia from synthesis gas comprising hydrogen and nitrogen, is exothermic and requires cooling in order to obtain high speed turning.

Even if the concentration of hydrogen and nitrogen in the synthesis gas is close to the stoichiometric composition for the formation of ammonia, complete reaction conversion into ammonia cannot be achieved by a single passing the synthesis gas through the catalytic layer. In addition, due to the exothermic nature of the synthesis of ammonia, the temperature increase during the passage through the layer of catalyst shifts the equilibrium concentration in the lower ammonia concentrations. There are several ways of cooling process of ammonia synthesis.

In conventional methods for producing ammonia from synthesis gas used in the ez ammonia flows over the catalyst for ammonia synthesis.

In direct cooling cool the synthesis gas is introduced into the partially reacted synthesis gas between the layers. The disadvantage of this cooling method is the dilution of the partially reacted gas ariagiovanni gas, resulting in lower ammonia concentrations in the stream of the product obtained by this method.

The indirect method of cooling the partially reacted synthesis gas is cooled by the cold gas, usually fresh synthesis gas in a heat exchanger located between the outlet and inlet holes of the two catalytic layers.

Now found that the rate of conversion of ammonia synthesis gas in ammonia is greatly increased if the cooling of the synthesis gas as it flow through the catalytic layer of the catalyst for ammonia synthesis occurs by heat transfer to the cooling agent, which is in continuous thermal contact with the process.

Thus, this invention provides a method of producing ammonia, comprising the operations: - contacting the ammonia synthesis gas with a catalyst for ammonia synthesis, which is located in the reaction zone in one or more catalytic tube; continuous cooling of the reaction zone by passing the zone of the stream.

In the most typical embodiment of the above method is performed in the Converter with one or more catalytic tube located in the shell for holding a cooling agent. The synthesis gas enters the upper part of the catalytic tube and passes through the reaction zone of the catalyst for ammonia synthesis. The heat released during the conversion of ammonia to hydrogen and nitrogen contained in the synthesis gas, are continuously transferred through the wall of the catalyst tube cooling medium surrounding the tube. During continuous cooling in this way the adiabatic temperature increase is essentially avoided, so that the method performs essentially isothermal. Isothermal transformation of synthesis gas leads to higher rates of conversion of gas into ammonia compared with known methods for the synthesis of ammonia from indirect or direct cooling of the partially reacted synthesis gas, where the cold gas is in contact with the catalyst under adiabatic conditions. After removing the heat of reaction from the reaction zone, the cooling fluid is continuously or periodically removed from the Converter and the outside is cooled by, for example, heat exchange with steam or water and return back to the env is TBE, formed by the outer wall of the catalyst tube and the inner wall of the cooling tube which concentrically surrounds the catalytic tube.

The predominant feature of the latter embodiment is able to avoid the application of the casing of the reactor near the catalytic tubes or run it from a material with a lower mechanical strength than conventional ammonia converters.

Preferably the cooling tube surrounding the catalytic tube design with a lower mechanical strength than the catalytic tube. In the event of failure of the catalytic tubes reactive gas flowing under high pressure inside the cooling tube, is directed to a space outside of the cooling tube. Thus, the pressure of the synthesis gas occurs outside of the cooling tube, and successfully avoid harmful reactions gas with a cooling agent.

A further purpose of the invention is to provide a Converter for receiving ammonia by the reaction of ammonia synthesis gas in the presence of a catalyst for the synthesis of ammonia and cooling the reaction as it flow through the catalyst synthesis, and the Converter includes at least one natalitia synthesis of ammonia, and at least one catalytic tube is located in the container with a cooling agent, as schematically shown in the accompanying Fig.1.

The cooling medium that is suitable as a cooling agent for the above method and reactor may be any solid product or liquid with the melting point and boiling below the desired temperature in the reaction zone, including the salt or mixture of salts, metals or liquids which are inert under the actual conditions of the method. These cooling agents include eutectic mixture of salts, such mixtures KNO3, NaNO3and NaNO2(supplied by Degussa), and eutectic mixture of NaOH and KOH. Additional eutectic mixture of salts and fluids are well known in the chemical industry. Normal temperature conditions of the above method are between 300 and 600oC. the temperature of the cooling agent should be maintained at a given level within the range of the working temperature by external cooling agent, as mentioned above.

The following embodiment of the invention is the removal of ammonia from the enriched ammonia gaseous product withdrawn from the catalytic tubes, which dostigao the regeneration of spent adsorbent is carried out by means of relieving pressure over the adsorbent, and removing the enriched ammonia gas is conducted like a branch, for example, oxygen or nitrogen in a well-known adsorption processes with differential pressure. Moreover, the ammonia can be separated from not subjected to conversion of synthesis gas by cooling and condensation of the ammonia-rich ammonia flowing stream in this way. Unreacted synthesis gas after separation from the ammonia in the gaseous product may then be resubmitted to the catalytic tube or omitted in the subsequent catalytic tube for further transformations, as shown schematically in Fig.2 and 3.

Example.

In the specific embodiment of the present invention feeding a synthesis gas pressure of 13.8 MPa pre-heated to 350oFrom and injected into the reactor, equipped with a 600 reactor tubes with an inner diameter of 80.1 mm Tube fill in the upper part of the standard iron catalyst for ammonia synthesis, and in the lower part of the standard ruthenium catalyst for ammonia synthesis. The synthesis gas is distributed through the pipes and reacts over a catalyst for ammonia synthesis. Catalytic tube surrounded by a shell. In the space between the shell and tubes circulates salt Raspe molten salt is used to remove heat released during the exothermic reaction of ammonia synthesis. The salt melt entered when 360oIn the cooling space, and leaves the reactor at 420oC. the Hot melt is cooled outside the reactor to 360oWith the heat exchanger in which heat is extracted from molten salt, is used to heat the synthesis gas. The cooled molten salt is then served by the pump back into the reactor. Passed through the catalyst unreacted synthesis gas enriched with ammonia leaves the tube and out of the reactor. The gas is cooled by heat exchange with fresh synthesis gas.

The table below shows the concentration of components in the gas stream at the inlet and outlet of the reactor, which is obtained in the above experiment.

The method according to the invention can be used in a single end-to-end section of the ammonia synthesis as well as in more standard, such as circular, section synthesis of ammonia or in combination with similar or other types of ammonia converters in more promising circular sections of the synthesis of ammonia, for example, including converters with a gas powered or converters with the purge gas. Get the ammonia can be separated from the enriched ammonia gaseous products which aid absorption. The removal of ammonia can be carried out in one or more transactions between and/or after each of the reaction zones.

Claims

1. The method of producing ammonia, comprising the operations of contacting the ammonia synthesis gas with a catalyst for ammonia synthesis, which is located in the form of the reaction zone in one or more catalytic tube, cooling the reaction zone by heat transfer communication with a cooling agent, and o-enriched ammonia flow resulting from the reaction zone, characterized in that the cooling of the reaction zone is performed with the enforcement of the way in isothermal conditions through the implementation of the circulation of the cooling agent inside the cooling tubes, each of which concentrically surrounds one catalytic tube, with a cooling agent selected from the group comprising salt, a mixture of salts and metals, having a melting point below the temperature in the reaction zone.

2. The method according to p. 1, characterized in that the ammonia synthesis gas in contact with the catalyst for ammonia synthesis, which is located in two or more reaction zones with intermediate removal of the enriched ammonia flowing between the reaction zones of photovoltages the conversion of ammonia synthesis gas and the flow of the produced ammonia, not affected by the conversion of ammonia synthesis gas is fed again into the reaction zone.

4. The method according to p. 2 or 3, characterized in that the separation is carried out by cooling the resulting flow and condensation of ammonia.

5. The method according to p. 2 or 3, characterized in that the separation is carried out by adsorption of ammonia contained in the output stream.

6. Converter for implementing the method under item 1, comprising at least one catalytic tube, adapted to receive the ammonia synthesis gas and holding the reaction zone of the catalyst for ammonia synthesis, and at least one cooling tube which concentrically surrounds the at least one catalytic tube and in which a cooling agent selected from the group comprising salt, a mixture of salts and metals having a melting temperature below the temperature in the reaction zone, and having a temperature to be maintained at a specified level to ensure implementation of the ongoing way in isothermal conditions.

7. This under item 6, characterized in that the wall of the cooling tube/tubes have a lower mechanical strength than the wall of the catalytic tubes/pipes.

 

Same patents:

The invention relates to a catalyst for the synthesis of ammonia from hydrogen and nitrogen

The invention relates to a method for joint production of ammonia and urea on the plant includes a reactor for the synthesis of ammonia synthesis reactor urea and the regeneration section of the urea
The invention relates to processes of chemical technology, and in particular to methods of production of ammonia

The invention relates to a method and installation for the combined production of ammonia and methanol, as well as to upgrade the installation of the ammonia synthesis to ensure such co-production

The invention relates to a method for production of ammonia from synthesis gas and Converter for its implementation
The invention relates to the production of ammonia by the catalytic conversion of synthesis gas
The invention relates to the production of ammonia and can be used in the chemical industry

The invention relates to a process for the preparation of natural gas for ammonia production

The invention relates to methods of co-production of ammonia and methanol

The invention relates to a method for joint production of ammonia and methanol

The invention relates to a device for the catalytic dehydrogenation of hydrocarbons, in particular for radial flow reactors, and can be used in the chemical and petrochemical industry

The invention relates to a device for the catalytic dehydrogenation of hydrocarbons and can be used in the petrochemical industry

The invention relates to a system for catalytic conversion and the method of carrying out exothermic reactions between, for example, propylene and hydropredict ethylbenzene to obtain propylene oxide using a solid heterogeneous catalyst

The invention relates to a device for the partial oxidation using an appropriate catalyst and to a method of partial oxidation

The invention relates to the field of chemistry and relates to a reactor block catalyst honeycomb structure, comprising a housing with connections for input of initial reagents and output of the target product, inside of which is placed a block catalyst honeycomb structure, through channels of which with respect to the incident flow is oriented at an angle equal to 90

The invention relates to the node allocator gas pockets to distribute a mixture of liquid hydrocarbons and hydrogen-containing gas(s)

The invention relates to a device for the catalytic dehydrogenation of hydrocarbons, in particular for radial flow reactors, and can be used in the petrochemical industry for the dehydrogenation of ethylbenzene to styrene

FIELD: sorption neutralization of gases.

SUBSTANCE: proposed device includes two parallel horizontal gas-tight reactors arranged in casing at spaced relation; each reactor includes at least two sections filled with bulk granulated adsorbent and closed over ends with partitions carrying ejection pneumatic haulage units mounted above flow divider; device is provided with inlet and outlet branch pipes for delivery and discharge of gas; provision is made for V-shaped slide at angle of generatrices exceeding slope of repose for bulk adsorbent; V-shaped slide of each reactor is provided with drain branch pipe; walls of central reservoir are combined with hood excluding bridging of adsorbent; hood is equidistant relative to slide. Mechanism for hermetic discharge of used adsorbent includes longitudinal screw feeder and discharge pipe fitted with swivel gate valve; direction of turn of spiral provided on screw feeder of discharge mechanism is opposite to direction of main spiral.

EFFECT: improved quality of neutralization of gases; enhanced operational safety.

2 cl, 6 dwg

Up!