# US 10,246,340 B2 · Ammonia synthesis system and method

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- Number: US 10,246,340 B2
- Document ID: US10246340B2
- Status: Granted
- Kind: B2
- Application number: 15/507,379
- Filed: 2015-04-21
- Published: 2017-10-05
- Granted: 2019-04-02
- Earliest claimed: 2014-09-05
- Assignees: Mitsubishi Heavy Industries Engineering, Ltd.
- Applicants: Mitsubishi Heavy Industries, Ltd.
- Inventors: Mikiya Sakurai; Yukio Tanaka; Naoya Okuzumi; Hiroyuki Osora; Haruaki Hirayama
- Web page: https://patentgrep.com/patent/US10246340B2

## CPC

- C01C 1/047: {by condensation}
- B01D 53/002: {by condensation}
- B01J 23/462: {Ruthenium}
- C01C 1/02: Preparation, {purification} or separation of ammonia
- C01C 1/0411: {characterised by the catalyst}
- C09K 5/04: the change of state being from liquid to vapour or vice versa
- F25B 9/002: {characterised by the refrigerant}
- B01J 23/58: with alkali- or alkaline earth metals
- B01J 23/63: with rare earths or actinides
- Y02P 20/52: using catalysts, e.g. selective catalysts
- 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)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

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.

## Claims

### Claim 1

An ammonia synthesis method comprising:
an ammonia synthesis step of synthesizing an ammonia gas from a raw material gas for ammonia synthesis;
a water-cooled or air-cooled cooling step of water-cooling or air-cooling a synthetic gas containing the obtained ammonia gas and an unreacted raw material gas without using a product ammonia as a chiller refrigerant;
an ammonia separation step of separating the synthetic gas after cooling into the ammonia gas and a liquid ammonia; and
a compression step of compressing a return raw material gas when the raw material gas containing the separated ammonia gas is returned to the ammonia synthesis step side as the return raw material gas, wherein
an ammonia concentration in the return raw material gas to be introduced into the ammonia synthesis step is 5 mol % or more, and an ammonia synthesis catalyst that synthesizes the ammonia gas is a ruthenium catalyst, and
the temperature of the synthetic gas after cooling, to be introduced in the ammonia separation step is from 30 to 50° C.

### Claim 2 (depends on 1)

An ammonia synthesis method according to claim 1, wherein the ammonia concentration in the return raw material gas to be introduced into the ammonia synthesis step is 10 mol %.