--- title: Fertilizers slug: fertilizers docTags: createdAt: 2024-12-10T16:03:35.113Z --- :::hint{type="info"} The fertiliser industry is essentially concerned with the provision of three major plant nutrients - nitrogen, phosphorus and potassium - in plant available forms. Most nitrogen fertilisers are derived from ammonia. Only very large sites include production of the whole range of fertilisers. Typically, an integrated site is focused on the production of nitrogen based fertilisers or phosphate fertilisers. ::: :::hint{type="warning"} **EU CBAM Reminder**: Greenhouse gas (GHG) emissions to be monitored in the fertilisers sector include carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions. ::: # Ammonia :::hint{type="info"} Ammonia (NH3) is synthesized from nitrogen and hydrogen. The most readily available source of nitrogen is atmospheric air. While hydrogen can be produced from various feedstocks, it is currently derived mostly from fossil fuels. Depending on the type of fossil fuel, two primary methods are used to produce hydrogen for ammonia production: **steam reforming** and **partial oxidation** (go to the [Chemicals](docId\:QFwgnAQ6zDkeIv2zI-m03) section for more details). Globally, most ammonia production capacity still relies on the steam reforming process. The majority of ammonia is used as a nitrogen source in fertilizers, while the remaining share is utilized in various industrial applications, such as the manufacture of plastics. Ammonia is also used in environmental protection measures, such as the removal of NOₓ from flue gases. Ammonia exists in two primary forms: **anhydrous ammonia**, which is pure ammonia without water content, and **aqueous ammonia**, also known as ammonium hydroxide, which is a solution of ammonia dissolved in water. Both are covered by the EU CBAM. The stream of CO2 from the production of ammonia is of high purity and can be separated, captured and transferred elsewhere for other uses such as urea production. ::: :::hint{type="warning"} **EU CBAM Reminder**: Ammonia produced is reported as 100% ammonia, whether in hydrous or anhydrous form. ::: ## Haber-Bosch with steam reforming :::hint{type="info"} Ammonia production via steam reforming involves converting natural gas (or biogas) into hydrogen (go to [chemicals](docId\:QFwgnAQ6zDkeIv2zI-m03) for more details), which is then combined with nitrogen to synthesize ammonia via the Haber-Bosch process. ::: :::hint{type="warning"} **EU CBAM Reminder**: Where biogas (gaseous fuel produced from biomass) is used, it shall fulfill the criteria for zero-rating of biomass emissions as per Section B.3.3 of Annex III of the [CBAM Implementing Regulation](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ%3AJOL_2023_228_R_0006#d1e32-113-1). If the biogas does not comply with these criteria, its carbon content shall be considered fossil carbon. ::: | **The EU CBAM covers the following production steps for Ammonia produced via the Haber-Bosch with steam reforming:** | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Production of hydrogen by steam reforming natural gas or biogas; | | Synthesis of ammonia from hydrogen and nitrogen, at high temperature and pressure in the presence of a catalyst, ammonia condensation, purification and storage (if applicable); | | **Emissions control**: for treating releases to air, water or ground. | ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/WIoSi2sqaoSlKhL6_DEC0_image.png "Ammonia (NH3) production by conventional steam reforming; Source: EFMA (2000). \"Production of Ammonia\", Best Available Techniques for Pollution Prevention and Control in the European Fertilizer Industry.") :::hint{type="danger"} **Where do GHG emissions originate?** - **The reforming reaction itself (\~60% of emissions)** When you burn natural gas to split methane into H₂ and CO₂, the carbon in the methane has to go somewhere. It leaves as CO₂ out of the stack after the water-gas shift step. This is a direct, unavoidable process emission — even a perfectly efficient plant produces it. - **Firing the reformer furnace (\~30–35%)** The steam methane reforming (SMR) reaction is endothermic — it needs constant heat input. That heat comes from burning more natural gas under the reformer tubes. Those combustion gases go straight to atmosphere as CO₂. This is why SMR plants are sometimes described as using natural gas both as a *feedstock *(the molecule you're reforming) and as a *fuel *(what you burn to heat the reactor). - **Electricity for compression (\~5–10%)** The Haber-Bosch synthesis loop runs at 150–300 bar. Compressing the gas takes a lot of energy — either grid electricity (indirect emissions) or steam turbines driven by recovered heat (which reduces but doesn't eliminate the footprint). ::: :::hint{type="success"} The diagram below shows the example of an installation producing 500,000 tonnes of ammonia via the steam reforming route. *Please note that these values are purely for explanatory and illustrative purposes, as each factory will have its unique design* **Inputs** Fuels: - Natural gas: 368,421,053 m3 --> 793,667.37 tCO2e Electricity: - Grid: 23,245 MWh → 13,565.78 tCO2e (indirect emissions) **Resulting in the following direct and indirect specific embedded emissions (SEE):** - Direct: 1.5873 tCO2e/tonne - Indirect: 0.0271 tCO2e/tonne ::: ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/WS7rgOlH-ofyaerz4FXlr_image.png) ## Haber-Bosch with partial Oxidation :::hint{type="info"} Ammonia production via **partial oxidation **involves converting heavy hydrocarbons, such as coal or heavy fuel oil, into synthesis gas (syngas), which is then processed to produce ammonia. ::: | **The EU CBAM covers the following production steps for Ammonia produced via the Haber-Bosch with partial oxidation: ** | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Production of hydrogen by gasification (partial oxidation); | | Synthesis of ammonia from hydrogen and nitrogen, at high temperature and pressure in the presence of a catalyst, ammonia condensation, purification and storage (if applicable); | | **Emissions control**: for treating releases to air, water or ground. | ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/YeZA3InvjFqcnaj1SwMWO_image.png "Ammonia (NH3) production by partial oxidation; Source: EFMA (2000). \"Production of Ammonia\", Best Available Techniques for Pollution Prevention and Control in the European Fertilizer Industry.") :::hint{type="danger"} **Where do GHG emissions originate?** - **The oxidation reaction itself (\~75–80% of emissions)** In POX, the carbon in the feedstock is oxidised to CO (then shifted to CO₂ in the downstream water-gas shift step). Because you're feeding a sub-stoichiometric amount of oxygen, not all carbon becomes CO₂ immediately — but after the WGS reactor, virtually all of it does. The heavier the feedstock (fuel oil, coal), the more carbon atoms per hydrogen atom, so the more CO₂ per kg H₂ produced. - **No furnace firing** POX is exothermic, so there's no external burner heating a reformer tube. That \~30–35% emission source from SMR simply disappears. This is the structural advantage of POX over SMR in terms of combustion emissions — but it's largely cancelled out by the oxidation reaction, because the feedstock itself is carbon-heavier. - **Electricity and oxygen production (\~10–15%)** POX requires a pure or enriched oxygen stream, which comes from an air separation unit (ASU). Cryogenic ASUs are energy-hungry — this adds an indirect emission source that SMR doesn't have to the same degree. Compression of syngas also contributes. ::: :::hint{type="success"} The diagram below shows the example of an installation producing 500,000 tonnes of ammonia via the partial oxidation route. *Please note that these values are purely for explanatory and illustrative purposes, as each factory will have its unique design* **Inputs** Fuels: - Lignite (Brown Coal): 1,170,000 tonnes --> 1,406,223 tCO2e Electricity: - Grid: 265,000 MWh → 154,654 tCO2e (indirect emissions) **Resulting in the following direct and indirect specific embedded emissions (SEE):** - Direct: 2.8124 tCO2e/tonne - Indirect: 0.3093 tCO2e/tonne ::: ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/czzgvoX69q4zLWhpxKKK2_image.png) # Nitric Acid (and sulphonitric acids) :::hint{type="info"} Nitric acid (HNO₃) is predominantly produced through the Ostwald process, which involves the catalytic oxidation of ammonia. In this process, ammonia is first oxidized in the presence of a platinum-rhodium catalyst to form nitric oxide (NO). The nitric oxide is then further oxidized to nitrogen dioxide (NO₂). Subsequently, nitrogen dioxide is absorbed in water within an absorption tower to yield nitric acid (HNO₃). This series of reactions is exothermic, allowing for the recovery of heat and power during the process. The majority of the nitric acid produced is utilized in the manufacture of inorganic fertilizers, primarily through neutralization with ammonia to form ammonium nitrate. The production of nitric acid generate nitrous oxide (N₂O) emissions, which is a highly potent greenhouse gas (GHG). ::: :::hint{type="warning"} **EU CBAM Reminder**: Nitrous oxide (N₂O) emissions shall be monitored using a Continuous Emission Monitoring System (**CEMS**) installed at an appropriate measurement point (measurement-based approach). Both abated and unabated emissions shall be monitored. Any N₂O emissions from the combustion of fuels are excluded from monitoring. ::: ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/bnw8cUINk4KITT_Ca9FNp_image.png "Overview of the production of nitric acid (HNO3); Source: infoMil (1999). \"Dutch notes on BAT for the production of nitric acid\" & EFMA (2000). \"Production of Nitric Acid\", Best Available Techniques for Pollution Prevention and Control.") | **The EU CBAM covers the following production steps for Nitric Acid production: ** | | -------------------------------------------------------------------------------------------------------------------- | | **Raw material preparation**: evaporation and filtration of ammonia and process air; | | Oxidation of ammonia to nitrogen oxide, all process steps; | | Further oxidation and absorption to nitrogen dioxide and absorption in water to form nitric acid, all process steps; | | **Emissions control**: for treating releases to air, water ground. | :::hint{type="danger"} **Where do GHG emissions originate?** - **N₂O from the catalytic combustion step (\~60–80% of total, as CO₂e)** This is the dominant source by far. When ammonia burns over the Pt/Rh catalyst at 850–950°C, a small fraction — typically 2–9 kg N₂O per tonne of HNO₃ — is produced as a side reaction instead of the desired NO. N₂O has a global warming potential of 265× CO₂ over 100 years, so even a small quantity dominates the carbon footprint completely. Without abatement, a nitric acid plant can emit 5–9 tCO₂e per tonne HNO₃ from N₂O alone. - **Indirect emissions from electricity (\~10–15%)** The process uses electricity for compressors and cooling. These are indirect emissions, dependent on the grid carbon intensity — exactly as in ammonia. - **Upstream ammonia (\~10–20% if attributed)** Ammonia is the feedstock, and producing it via Haber-Bosch already carries \~1.6–2.4 tCO₂e/t NH₃. Under CBAM, these embedded emissions in the ammonia input must be carried forward into the nitric acid's declared SEE. This makes the choice of ammonia source (grey, blue, green) very significant. ::: # Urea :::hint{type="info"} Urea (CH₄N₂O) is synthesized by reacting ammonia (NH₃) with carbon dioxide (CO₂) at high pressure to form ammonium carbamate, which is then dehydrated to produce urea. Typically, the ammonia and CO₂ used in this process are sourced from on-site production facilities, often integrated within the same plant. ::: :::hint{type="warning"} 1️⃣** EU CBAM Reminder**: Where CO₂ is received from another installation as a process input, the CO₂ received and not bound in urea shall be considered an emission if it has not already been counted as an emission by the installation where the CO₂ was produced under an eligible monitoring, reporting, and verification system. ::: :::hint{type="warning"} 2️⃣** EU CBAM Reminder**: For each fertilizer grade, embedded emissions shall be calculated separately taking into account the relevant mass of precursors used and applying average embedded emissions during the reporting period for each of the precursors. ::: ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/nFhqzF5ur0b29dMCO6lCC_image.png "Overview of the production of urea by total recycling processes; Source: infoMil (2001). \"Dutch notes on BAT for the production of fertilisers\".") | **The EU CBAM covers the following production steps for Urea production: ** | | --------------------------------------------------------------------------------- | | **Raw material preparation**: evaporation and filtration of ammonia, CO2; | | **Production of urea**: all process steps, from synthesis to particle formation; | | **Emissions control**: for treating releases to air, water or ground; | :::hint{type="danger"} **Where do GHG emissions originate?** - **Upstream ammonia (\~50–60% of SEE)** Ammonia carries its embedded emissions into urea. At roughly 0.57 t NH₃ per tonne of urea, and \~1.6–2.4 tCO₂e/t NH₃, this alone contributes around 0.9–1.4 tCO₂e/t urea before anything else is counted. - **The CO₂ input — the accounting puzzle (\~30–40%)** The CO₂ fed into the urea reactor came from the SMR process. That CO₂ was already "generated" when methane was reformed. **Who owns those emissions, the ammonia or the urea?** Under CBAM, the CO₂ is considered **transferred** from the ammonia/hydrogen production process to the urea process. It must be deducted from the ammonia's embedded emissions and added to urea's. **Can the emissions captured in urea be deducted?** No. Under CBAM, urea is currently not eligible to be considered as chemically and permanently binding CO₂. The CO₂ that was captured in the urea molecule is released back to atmosphere within days to weeks. So from a full lifecycle perspective, urea provides no permanent carbon storage — the CO₂ is merely delayed, not avoided. - **Electricity and utilities (\~5–10%)** Compression, pumping, and concentration of urea solution (urea is sold as 46% solid prills or as 32.5% aqueous solution for AdBlue). Evaporators and prilling towers consume steam and electricity. ::: :::hint{type="success"} The diagram below shows the example of an installation producing 500,000 tonnes of urea. *Please note that these values are purely for explanatory and illustrative purposes, as each factory will have its unique design* **Inputs** Fuels: - Natural gas: 491,000,000 m3 --> 1,057,731.84 tCO2e Electricity: - Grid: 84,318 MWh → 49,207.98 tCO2e (indirect emissions) The above inputs result in the following internal precursor emissions: - Ammonia: 500,000 tonnes - Direct embedded emissions: 793,667.37 tCO2e - Indirect embedded emissions: 13,565.78 tCO2e For simplification purposes, this example assumes that all the ammonia and CO₂ emissions from its production are used in urea production. **Resulting in the following direct and indirect specific embedded emissions (SEE):** - Direct: 2.1155 tCO2e/tonne - Indirect: 0.0984 tCO2e/tonne ::: ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/y7tS8FDG1_yYS0togRCWE_image.png) # Mixed Fertilizers :::hint{type="info"} The production of nitrogen-containing mixed fertilizers, such as ammonium salts and NP, NK, and NPK formulations, encompasses a variety of operations. These processes include mixing, neutralization, and particle formation methods like granulation or prilling. Depending on the specific fertilizer formulation, these operations may involve solely physical mixing or incorporate chemical reactions to achieve the desired nutrient composition. In the context of NPK fertilizers, which provide a balanced supply of nitrogen (N), phosphorus (P), and potassium (K), production methods can vary. One common approach is the nitrophosphate process (see graph below), also known as the Odda process, which involves acidifying phosphate rock with nitric acid to produce a mixture of phosphoric acid and calcium nitrate. This mixture is then further processed, often with the addition of ammonia and potassium sources, to produce NPK fertilizers. ::: :::hint{type="warning"} **EU CBAM Reminder**: The amounts of different nitrogen compounds contained in the final product must be recorded in accordance with [Regulation (EU) 2019/1009](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02019R1009-20241117): - Content of N as ammonium (NH₄⁺); - Content of N as nitrate (NO3-); - Content of N as Urea; - Content of N in other (organic) forms. ::: ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/GSasCtbIyI90zq7amn1BA_image.png "Overview of the production of NPK fertilisers from phosphate rock or SSP/TSP; Source: TWG on LVIC-AAF (2006). \"Information provided after the 2nd TWG meeting\", personal communication.") | **The EU CBAM covers the following production steps for Mixed Fertilizer production: ** | | -------------------------------------------------------------------------------------------- | | Raw material preparation; | | Production of mixed fertiliser: all process steps; | | **Emissions control**: for treating releases to air, water or ground; | :::hint{type="success"} The diagram below shows the example of an installation producing 200,000 tonnes of mixed fertilizers. *Please note that these values are purely for explanatory and illustrative purposes, as each factory will have its unique design* **Inputs** - External Precursors: - Ammonia (NH3): 66,000 tonnes - Direct embedded emissions: 244,200 tCO2e - Indirect embedded emissions: 11,880 tCO₂e - Urea(CH₄N₂O): 66,000 tonnes - Direct embedded emissions: 156,420 tCO2e - Indirect embedded emissions: 9,240 tCO₂e Intermediate Goods: - Potassium Chloride (KCI): 66,000 tonnes → no GHG emissions - Single Superphosphate (SSP): 50,000 tonnes → no GHG emissions - Phosphoric Acid: 44,000 tonnes --> no GHG emissions - Sulfuric Acid: 25,000 tonnes --> no GHG emissions Fuels: - Natural gas: 48,631,579 m3 --> 104,764.09 tCO2e (direct emissions) Electricity: - Grid: 200,000 MWh → 116,720 tCO2e (indirect emissions) **Resulting in the following direct and indirect specific embedded emissions (SEE):** - Direct: 2.5269 tCO2e/tonne - Indirect: 0.6892 tCO2e/tonne ::: ![](https://api.archbee.com/api/optimize/x8OHL8j_3t12U2ealHN0O/-N1_MYqCwFdReRkv6sp0u_image.png)