# US 9,040,011 B2 · Process for producing ammonia synthesis gas

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,040,011 B2
- Document ID: US9040011B2
- Status: Granted
- Kind: B2
- Application number: 12/744,748
- Filed: 2008-11-06
- Published: 2010-12-02
- Granted: 2015-05-26
- Earliest claimed: 2007-11-27
- Assignees: Casale SA
- Applicants: Ermanno Filippi; Marco Badano; Geoffrey Frederick Skinner
- Inventors: Ermanno Filippi; Marco Badano; Geoffrey Frederick Skinner
- Web page: https://patentgrep.com/patent/US9040011B2

## CPC

- C01B 3/025: Preparation or purification of gas mixtures for ammonia synthesis
- C01B 3/382: Processes with two or more reaction steps, of which at least one is catalytic, e.g. steam reforming and partial oxidation
- C01B 3/48: followed by reaction of water vapour with carbon monoxide
- C01B 2203/0233: the reforming step being a steam reforming step
- C01B 2203/0244: the reforming step being an autothermal reforming step, e.g. secondary reforming processes
- C01B 2203/025: containing a partial oxidation step
- C01B 2203/0415: Purification by absorption in liquids
- C01B 2203/042: Purification by adsorption on solids
- C01B 2203/0435: Catalytic purification
- C01B 2203/047: the impurity being carbon monoxide
- C01B 2203/0475: the impurity being carbon dioxide
- C01B 2203/068: Ammonia synthesis
- C01B 2203/1235: Hydrocarbons
- C01B 2203/142: At least two reforming, decomposition or partial oxidation steps in series
- C01B 2203/147: Three or more purification steps in series
- C01C 1/0405: {from N2 and H2 in presence of a catalyst}
- Y02P 20/52: using catalysts, e.g. selective catalysts
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01C: AMMONIA; CYANOGEN; COMPOUNDS THEREOF ({metal hydrides, monoborane, diborane or addition complexes thereof C01B6/00}; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; azides C01B21/08; {compounds other than ammonia or cyanogen, containing nitrogen, non-metals and optionally metals C01B21/082}; metal imides or amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; compounds containing silicon C01B33/00; compounds containing boron C01B35/00)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present invention concerns a process for producing ammonia synthesis gas from the reforming of hydrocarbons with steam in a primary reformer (1) equipped with a plurality of externally heated catalytic tubes and then in a secondary reformer (2) together with an oxidant gas. In this process, the reaction of said hydrocarbons with said steam in said primary reformer (1) is performed at an operating pressure of at least 45 bar in the catalytic tubes and a flow of essentially pure oxygen or oxygen-enriched air is added to said secondary reformer as oxidant gas for substantially reforming together with said all the hydrocarbons content of said product gas exiting the primary reformer (1). In the case essentially pure oxygen is used as oxidant gas, a flow of nitrogen is added downstream the secondary reformer (2) to reach a N2/H2 molar ratio corresponding to or close to the stoichiometric ratio for ammonia synthesis. This process allows to obtain high synthesis gas production capacities and lower investment and energy costs.

## Claims

### Claim 1

A process for producing ammonia synthesis gas, the process comprising the steps of:
feeding a gas flow comprising hydrocarbons and a gas flow comprising steam to a primary reformer equipped with a plurality of externally heated catalytic tubes,
reacting said hydrocarbons with said steam in the catalytic tubes of said primary reformer at an operating pressure of at least 45 bar in the catalytic tubes, obtaining a product gas,
feeding said product gas and a flow of oxidant gas to a secondary reformer,
subjecting said product gas to reaction with said oxidant gas and then to secondary reforming so as to reform all the hydrocarbons content of said product gas exiting the primary reformer and obtain a reformed gas comprising hydrogen, carbon oxides and unreacted steam,
removing carbon oxides from said reformed gas, obtaining a synthesis gas suitable for synthesis of ammonia,
wherein said oxidant gas is oxygen-enriched air having an appropriate N2/O2 molar ratio to obtain a reformed gas having a content of nitrogen corresponding to the content required for the stoichiometric H2/N2 molar ratio for ammonia synthesis.

### Claim 2 (depends on 1)

The process according to claim 1, said oxygen-enriched air having a O2 content from 22 to 50 in mol % and being supplied to the secondary reformer in a ratio of 0.35 to 0.5 mol of oxygen content of the enriched air stream per mol of carbon in hydrocarbons entering the primary reformer or a pre-reformer if used.

### Claim 3 (depends on 1)

The process according to claim 1, said operating pressure in the catalytic tubes of the primary reformer being in the range of 45-100 bar.

### Claim 4 (depends on 1)

The process according to claim 1, the outlet temperature of said gas product from the tubes of the primary reformer being in the range of 650-850° C.

### Claim 5 (depends on 4)

The process according to claim 4, said outlet temperature being in the range of 700-770° C.

### Claim 6 (depends on 1)

The process according to claim 1, said step of removing carbon oxides from said reformed gas comprising the following operative stages:
removing carbon monoxide from said reformed gas by catalytic conversion with unreacted steam into carbon dioxide and hydrogen, so obtaining a reformed gas essentially deprived of carbon monoxide and some steam,
removing carbon dioxide from reformed gas essentially deprived of carbon monoxide and some steam to obtain a reformed gas still including traces of carbon oxides,
removing said traces of carbon dioxide by catalytic conversion to methane.

### Claim 7 (depends on 3)

The process according to claim 3, wherein said operating pressure in the catalytic tubes of the primary reformer is in the range of 60-80 bar.

### Claim 8 (depends on 1)

The process for producing ammonia from ammonia synthesis gas, the process comprising the steps of obtaining ammonia synthesis gas according to claim 1, and reacting said synthesis gas in an ammonia synthesis loop under conditions effective to obtain ammonia.