C01B 21/04
Purification or separation of nitrogen
Official title: Purification or separation of nitrogen (by liquefying F25J)
C01B21/04 (Purification or separation of nitrogen) appears on 345 US grants and 211 published applications in this corpus.
Search patents in C01B- Granted patents
- 345
- Published applications
- 211
- Assignees
- 204
- Inventors
- 809
- Latest grant
- 17 Mar 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 3 | 0 |
| 1978 | 1 | 0 |
| 1979 | 0 | 0 |
| 1980 | 2 | 0 |
| 1981 | 3 | 0 |
| 1982 | 3 | 0 |
| 1983 | 3 | 0 |
| 1984 | 5 | 0 |
| 1985 | 3 | 0 |
| 1986 | 5 | 0 |
| 1987 | 4 | 0 |
| 1988 | 8 | 0 |
| 1989 | 11 | 0 |
| 1990 | 7 | 0 |
| 1991 | 14 | 0 |
| 1992 | 11 | 0 |
| 1993 | 12 | 0 |
| 1994 | 10 | 0 |
| 1995 | 12 | 0 |
| 1996 | 14 | 0 |
| 1997 | 12 | 0 |
| 1998 | 9 | 0 |
| 1999 | 15 | 0 |
| 2000 | 11 | 0 |
| 2001 | 8 | 0 |
| 2002 | 1 | 4 |
| 2003 | 12 | 5 |
| 2004 | 4 | 8 |
| 2005 | 3 | 7 |
| 2006 | 0 | 6 |
| 2007 | 4 | 7 |
| 2008 | 4 | 5 |
| 2009 | 1 | 3 |
| 2010 | 3 | 10 |
| 2011 | 7 | 7 |
| 2012 | 5 | 7 |
| 2013 | 9 | 6 |
| 2014 | 6 | 10 |
| 2015 | 12 | 11 |
| 2016 | 10 | 15 |
| 2017 | 12 | 13 |
| 2018 | 9 | 18 |
| 2019 | 12 | 14 |
| 2020 | 10 | 8 |
| 2021 | 13 | 9 |
| 2022 | 2 | 11 |
| 2023 | 7 | 6 |
| 2024 | 4 | 8 |
| 2025 | 3 | 9 |
| 2026 | 3 | 4 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Ambient air separation and SOEC front-end for ammonia synthesis gas production17 Mar 2026US 12,577,686 B2Haldor TopsøE A/S
- System for obtaining high purity nitrogen in nitrogen gas purification applications and a method thereof17 Feb 2026US 12,552,669 B2Mikropor Makina Sana Yi Ve Ticaret Anonim Sirketi
- Integrated ammonia and sulfuric acid production plant and process20 Jan 2026US 12,528,752 B2Chemetics Inc.
- System and method for synchronously recovering nitrogen and carbon dioxide from boiler flue gas25 Nov 2025US 12,478,915 B2Beijing Carbon Cycle Technology
- Apparatus, system and method for generating nitrogen gas from fuel-cell exhaust gas23 Sep 2025US 12,424,645 B2Micro Control Systems Ltd.
- High efficiency electro-photocatalysts16 Jul 2026US 2026/0199827 A1
- Processes and apparatuses for treating nox separated from carbon dioxide28 May 2026US 2026/0145938 A1Uop LLC
- Combined Inert Gas and Instrument Air System for Marine Applications30 Apr 2026US 2026/0115651 A1Air Products and Chemicals, Inc.
- Systems, methods, and techniques for processing hydrogen sulfide19 Mar 2026US 2026/0078001 A1Ohio State Innovation Foundation
- Floating power generation unit18 Dec 2025US 2025/0382035 A1
Most cited
By later US patents
- Process for separating components of a gas stream137US 4,701,187 AAir Products and Chemicals, Inc. · 1987
- Process for the separation/recovery of gases114US 6,179,900 B2GKSS-Forschungszentrum Geesthacht GmbH · 2001
- Process for recovering hydrogen from a multi-component gas stream113US 4,654,063 AAir Products and Chemicals, Inc. · 1987
- Layered manifold pressure swing adsorption device and method106US 6,565,635 B2QuestAir Technologies Inc. · 2003
- Liquid absorbent solutions for separating nitrogen from natural gas103US 6,136,222 ABend Research, Inc. · 2000