Location: RER - Europe
This dataset represents the production of 1 kg of liquid ammonia using the partial oxidation process. Ammonia is a colourless gas with a penetrating, pungent suffocating odour. It is liquid when under pressure. It is hygroscopic and soluble in water
(89.9 g/L at 0°C).
The most important use for ammonia is as a supply of vital agricultural nitrogen for crops. It is either applied as a fertiliser directly or it is used as a feedstock in the manufacture of urea, ammonium nitrate or nitric acid. The industrial use of ammonia as a nitrogen source has consumed an increasingly greater share of total ammonia production, amounting now to about 20% of world output. Virtually all nitrogen used in the chemical industry enters the process as ammonia. The major uses of industrial ammonia-nitrogen , in part after conversion into nitric acid, are the manufacture of plastics and fibres. Other important applications are the manufacture of explosives, hydrazine, amines, amides, nitriles, and other organic nitrogen compounds serving as intermediates for dyes and pharmaceuticals. The most important products manufactured from ammonia are nitric acid, urea, sodium cyanide and sodium carbonate.
Ammonia is used in the area of environmental protection to remove SO2 and NOx from steam boiler flue gases. The resulting ammonium sulphate (and sometimes ammonium nitrate) is marketed as a fertiliser product. Liquid ammonia has a considerable importance as a solvent. Ammonia is also used in the nitriding of steel. It is also still used as a refrigerant in industrial and commercial refrigeration and air-conditioning installations.
Ammonia is an inexpensive and easily managed starting material for manufacturing protective gas mixtures for chemical products and for metal-working processes. It is also used for manufacturing hydrogen and is even proposed for use in energy-related applications.
The main data sources for this dataset are EFMA (2000) and Frischknecht (1999). Additional sources are Davis (1999), Patyk and Reinhardt (1997) and Dones et al. (2007). UNEP (1998) is taken into account for plausibility checks and comparison reasons.
Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. ecoinvent report No. 8, v2.0. EMPA Dübendorf, Swiss Centre for Life Cycle Inventories, Dübendorf, CH.
European Fertiliser Manufacturers´ Association (2000) Production of Ammonia. Best Available Techniques for Pollution Prevention and Control in the European Fertiliser Industries. Booklet N°1. Brussel. http://www.efma.org/publications/BAT%202000/bat01/booklet1.pdf.
Frischknecht R. (1999) Umweltrelevanz natürlicher Kältemittel. Ökobilanzen von Wärmepumpen und Kälteanlagen. Herstellung Ammoniak (NH3, R-717). Bundesamt für Energie.
Davis J. and Haglund C. (1999) The Swedish Institute for Food and Biotechnology. SIK Report N° 654 1999 Life Cycle Inventory of Fertilizer Production. pages 57-67.
Dones R., Bauer C., Bolliger R., Burger B., Faist Emmenegger M., Frischknecht R., Heck T., Jungbluth N., Röder A., Tuchschmid M. (2007) Life Cycle Inventories of Energy Systems: Results for Current Systems in Switzerland and other UCTE Countries. ecoinvent report No. 5. Paul Scherrer Institut Villigen, Swiss Centre for Life Cycle Inventories, Dübendorf, CH.
United Nations Environment Programme (UNEP) Industry and the Environment, United Nations Industrial Development Organization (UNIDO) and International Fertiliser Association (IFA). (1998) Mineral Fertiliser Production and the Environment. Part 1. The Fertiliser Industry's Manufacturing Processes and Environmental Issues. United Nations Publications, New York.
Patyk A. and Reinhardt G. (1997) Düngemittel - Energie- und Strombilanzen. Vieweg Verlag. Braunschweig/Wiesbaden.
Undefined unit processes (UPRs) are the unlinked, multi-product activity datasets that form the basis for all of the system models available in the ecoinvent database. This is the way the datasets are obtained and entered into the database by the data providers. These activity datasets are useful for investigating the environmental impacts of a specific activity (gate-to-gate), without regard to its upstream or downstream impacts.
According to EFMA (2000), two main types of production processes for ammonia synthesis gas are currently in operation in Europe:
- Steam reforming of natural gas or other light hydrocarbons (natural gas liquids, liquefied petroleum gas, naphtha) and
- Partial oxidation of heavy fuel oil or vacuum residue
Coal gasification and water electrolysis are no longer in use in the European ammonia industry. The ammonia synthesis process is principally independent of the type of synthesis gas production process, but synthesis gas quality influences the loop design and operation conditions.
This dataset represents the production of liquid ammonia by partial oxidation. The partial oxidation process is used for the gasification of heavy feedstocks such as residual oils and coal. Extremely viscous hydrocarbons and plastic wastes may also be used as fractions of the feed. Thus, the partial oxidation process offers an alternative for future utilisation of such wastes.
An air separation unit is required for the production of oxygen for the partial oxidation step. The nitrogen is added in the liquid nitrogen wash to remove impurities from the synthesis gas and to get the required hydrogen/nitrogen ratio in the synthesis gas.
The partial oxidation gasification is a non-catalytic process taking place at high pressure and temperature. The simplified reaction pattern is:
-CHn- + 0.5 O2 → CO + n/2 H2
Carbon dioxide, methane and some soot are formed in addition. The sulphur compounds in the feed are converted to hydrogen sulphide. Mineral compounds in the feed are transformed into specific ashes. The process gas is freed from solids by water scrubbing after waste heat recovery and the soot is recycled to the feed. The ash compounds are drained with the process condensate and/or together with a part of the soot. The heavy metals are recovered. The hydrogen sulphide in the process gas is separated in a selective absorption step and reprocessed to elementary sulphur in a Claus unit.
The shift conversion usually has two high temperature shift catalyst beds with intermediate cooling. Steam for the shift conversion is supplied partially by a cooler-saturator system and partially by steam
CO2 is removed by using an absorption agent that might be the same as that in the sulphur removal step. Residual traces of absorption agent and CO2 are then removed from the process gas, before final purification by a liquid nitrogen wash. In this unit practically all the impurities are removed and nitrogen is added to give the stoichiometric hydrogen to nitrogen ratio.
The ammonia synthesis is quite similar to that used in steam reforming plants, but simpler and more efficient, due to the high purity of synthesis gas from liquid nitrogen wash units and the synthesis loop not requiring a purge.
No major improvements are to be expected concerning process efficiency and plant investment costs. However, partial oxidation will continue to be interesting in the future, due to its feedstock flexibility. The separation and disposal of the soot and especially the ashes are necessary to adapt to deteriorating residue qualities or alternative raw material sources.
Production of Carbon Dioxide: Carbon Dioxide is a by-product generated according to a stoichiometric conversion and may be recovered for down stream uses.