Nitric Acid Production Patents: Who Leads, Where the Gaps Are 2026
- 59.6% concentration. The top five assignees account for 221 of 371 records in scope — the field is held tightly at the top, not spread across many small filers.
- Filing has cooled since 2022. Activity peaked at 59 records in 2022 and has declined since, with the most recent year understated by publication lag.
- Separation claims dominate. B01D subclass records sit at 65.2% of the 371 records in scope, close behind the core C01B chemistry itself at 90.8%.
What this landscape covers
This landscape tracks patent families filed against nitric acid production processes: ammonia oxidation, platinum gauze catalysis, N2O abatement, absorption tower design, acid concentration and tail gas treatment. The scope is defined by IPC classes C01B21, B01J23 and B01D53, and spans 371 published records filed between 2015 and mid-2026.
Filing offices skew toward China, Europe and the United States, reflecting where nitric acid capacity is built and where environmental compliance on N2O and NOx emissions is enforced most strictly. The assignee base includes established engineering contractors and fertilizer producers alongside a long tail of single-filing entrants.
Filing trend and technology composition
Two views of the same 371 records: how filing volume has moved year over year, and which IPC subclasses carry the claim density.
Filing trend, 2017–2026
Filings rose from 15 in 2017 to a peak of 59 in 2022, then declined to 3 by the most recent partial year. Because publication typically lags filing by around 18 months, the last one to two years understate true filing activity — treat the recent drop as partly an artefact of the data cut-off, not solely a real slowdown.
IPC subclass composition
C01B (non-metallic elements and inorganic compounds) covers 90.8% of the 371 records, confirming this is fundamentally a core-chemistry field. B01D (separation processes) reaches 65.2%, well ahead of B01J (catalysis, 22.9%), showing that absorption and gas-separation engineering carries as much claim weight as the catalytic chemistry itself. Records can carry multiple classes, so these shares sum to more than 100%.
Shares are the percentage of the 371 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Nitric Acid Production with Eureka
This page is one run against one query. Ask Eureka your own question about nitric acid production and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a recent filing
WO2025068327A1 — System for the start-up and shut-down of a nitric acid production plant
Filed by Yara International, this application addresses a conventional nitric acid plant architecture — absorption tower, tail gas treatment unit — by adding an in-line fuelled burner downstream of the absorption tower and upstream of the tail gas treatment unit. The burner heats tail gas before it expands through a turbine and releases to atmosphere, targeting the start-up and shut-down phases specifically rather than steady-state operation.Abstract condensed from the original filing.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4153429A | Selective adsorption of NO{HD x {b from gas streams | 56 |
| 2 | US6165435A | Method and production of nitric acid | 35 |
| 3 | WO2001051182A1 | METHOD FOR THE REMOVAL OF NOx AND N2O FROM THE RESIDUAL GAS IN NITRIC ACID PRODUCTION | 34 |
| 4 | EP0799794A1 | Oxygen injection in nitric acid production | 34 |
| 5 | US5985230A | Nitric acid production | 33 |
| 6 | CN110540178A | 一种中压法硝酸生产工艺及其生产设备 | 30 |
| 7 | EP0808797A2 | Direct oxygen injection in nitric acid production | 29 |
| 8 | US6264909B1 | Nitric acid production and recycle | 26 |
| 9 | US20170334722A1 | Method for Removing N2O and NOx From the Nitric Acid Production Process, and an Installation Suitable for Same | 25 |
| 10 | CN1395502A | 从来自硝酸生产的残余气体中除去NOx和N2O的方法 | 23 |
Citation counts favour older records that have had more time to accumulate citations within this corpus — read them as a signal of influence, not current importance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Three patterns stand out once the ranking, the trend and the IPC composition are read together.
The top of the field is tightly held
With 221 of 371 records concentrated among five assignees, and 72.8% among ten, new entrants are filing into a space where the leading engineering contractors and fertilizer majors already hold broad coverage across ammonia oxidation and absorption design.
Filing has plateaued past its peak
Volume rose steadily to 2022 then declined, and recent-year assignee data shows several leading filers at zero activity in the latest year while at least one shows renewed filing. This is consistent with a mature core process attracting selective, not broad, re-investment.
Separation and tail-gas engineering rivals core chemistry
B01D records sit at 65.2% of the 371 in scope, just behind C01B at 90.8% — meaning most filings pair the core nitric acid chemistry with a separation, absorption or tail-gas claim rather than filing on chemistry alone.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to nitric acid production, with the prior art for and against each one.
Who is filing, and where the coverage thins
The ranked list covers 90 companies counted by records — not a top-50 or top-100 cut, but the full set the data returns. A small group of engineering contractors and fertilizer producers sit well ahead of a long tail of single or occasional filers.
A single filer well ahead of the field
The leading assignee holds 65 records against a fifth-place figure of 19 and a tenth-place figure of 6 — a steep drop-off that signals a genuine leader rather than a crowded top tier.
Corporate group filings cluster together
The ten identified co-assignee pairs are dominated by affiliated engineering entities filing jointly, consistent with large plant-engineering groups routing patents through multiple subsidiary names rather than independent collaboration.
China leads receiving offices, Europe and the US follow
China accounts for 77 filings, ahead of the European Patent Office at 62 and the United States at 42, with Australia, Canada and WIPO PCT filings following behind — a spread that tracks where nitric acid capacity is being built and licensed.
| Assignee | Recent year | YoY |
|---|---|---|
| Yara International ASA | 2 | +100% |
| Casale SA | 0 | -100% |
| ThyssenKrupp Uhde GmbH | 0 | — |
| ThyssenKrupp Industrial Solutions AG | 0 | — |
| Uhde GmbH | 0 | — |
| Stamicarbon BV | 0 | — |
| Uhde GmbH | 0 | — |
| Drinkard Metalox Inc. | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, licensing or new filing.
Map claims against the leading assignee's portfolio
With one filer holding 65 of 371 records, a freedom-to-operate review should start by mapping its claim scope across absorption tower and tail-gas treatment before drafting adjacent claims.
Explore assignee portfolios in EurekaProbe the under-claimed branches
Electrolytic routes, heat-exchange integration and direct-contact cooling show comparatively thin filing relative to the core chemistry classes, and may offer more open claim space.
Run a white-space search in EurekaTrack post-2022 momentum by assignee
Filing has cooled since the 2022 peak, but not uniformly — some assignees show renewed activity while others have gone quiet, which matters for competitive monitoring.
Set up assignee alerts in EurekaCommon questions on nitric acid production patents
The ranking covers 90 companies counted by records, and it is led by a single assignee with 65 records, well ahead of the fifth-place company at 19 and tenth place at 6. The top five assignees combined hold 221 of the 371 records in scope, or 59.6%, which means the field is concentrated rather than evenly spread. Engineering contractors that design and license full nitric acid plants dominate this leading group, alongside at least one major fertilizer producer.
Filing rose from 15 records in 2017 to a peak of 59 in 2022, then declined toward the most recent partial year. Because patent publication typically lags filing by around 18 months, the last one to two years in any trend chart will understate real activity, so the apparent drop after 2022 is partly a data-cutoff effect rather than a confirmed slowdown. Recent-year momentum data shows a mixed picture across individual assignees, with some at zero activity and at least one showing renewed filing.
The core chemistry, IPC class C01B, appears in 90.8% of the 371 records in scope, confirming this is fundamentally a chemical-process field. Separation processes under B01D, covering absorption towers and tail-gas treatment, appear in 65.2% of records, nearly as prevalent as the core chemistry itself. Catalysis-specific claims under B01J appear in 22.9% of records, and smaller shares touch electrolytic production, heat exchange and steam power recovery, since a single record can carry more than one class.
China is the leading receiving office with 77 filings, ahead of the European Patent Office at 62 and the United States at 42. Australia, Canada and WIPO's PCT route follow with smaller but meaningful counts of 32, 31 and 22 respectively. This spread tracks the geography of nitric acid production capacity and the regulatory pressure around NOx and N2O emissions in each region.
Relative to the dominant C01B and B01D classes, electrolytic nitric acid production under C25B, heat-exchange integration under F28D, direct-contact gas cooling under F28C and steam power recovery under F01K each cover only a few percent of the 371 records in scope. That thinner coverage does not guarantee an easy grant, but it does suggest these branches carry less accumulated prior art than the core absorption and catalytic chemistry, making them worth a focused prior-art search before drafting.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.