How is ammonium produced

In this process, the aim is to lower the operational pressures and temperatures which will lead to the production of ammonia at five times the conversion rate of the Haber-Bosch process.

In this form of physical activation, the microwave plasma process is able to activate both nitrogen and hydrogen, and produce ions and free radicals that react over the catalyst surface in order to produce ammonia.

One of the benefits of this process is that under the appropriate conditions, microwave heating is able to heat the catalyst selectively to reach the required temperature without the need for reactions to take place and without heating the bulk environment.

This arrangement of a catalyst with a high temperature within a cool environment results in lower overall reaction temperatures and enhances the energy efficiency. In addition, as stated by WVU , the simplified design of this process is due to its low operational pressure.

The low operational pressure of this process enables it to be a better fit with renewable energy sources, since the system is reportedly able to be turned on and off easily. As the efficiency of ammonia production in nature is very high, electrochemists have attempted to utilize these enzymes for industrial applications of ammonia synthesis such as in the study conducted by Loney et al.

Furthermore, peptide functionalized catalysts were developed and tested in an Anion Exchange Membrane AEM -based system. The material used in this catalyst shows promising results compared to conventional catalyst approaches.

Szymanski and Gellett also state that the electrochemical processes are modular and are able to be coupled with renewable energy sources such as solar and wind and also have the capability to function at relatively lower temperatures and pressures compared to the larger scale conventional ammonia production processes. For this reaction to occur, a catalyst is required that is selective to ammonia production.

In order to address this issue, Szymanski and Gellett conducted a feasibility study in order to enhance ammonia selectivity by tailoring a nanoparticle catalyst morphology and utilizing peptides resulting from nitrogenase a naturally occurring nitrogen splitting enzyme in order to direct the desired reaction.

Greenlee et al. Life Cycle Assessment LCA is a primary technique used to support decision making for sustainable development in production. A number of studies have been conducted on the comparative LCA of sustainable ammonia production pathways. These studies include Bicer et al.

Tallaksen and Reese compared both approaches in terms of the usage of energy and carbon emissions. However, Arora et al. However, the system boundary selected by Arora et al. However, in this study, coal gasification to ammonia production was priced lower than the other processes discussed due to lower energy consumption, feedstock cost, and not consuming significant amounts of energy related to carbon dioxide stream compression.

Makhlouf et al. The system boundary for the LCA differs in the two studies. In Makhlouf et al. In addition, Makhlouf stated that when calculating the GHG balance, only the amount of natural gas utilized as fuel was considered and the amount of process gas was not taken into account. The outcome of the study shows that the energy requirement for ammonia production by the SMR of natural gas in Algeria was This figure was said to be Arora, et al.

All three configurations were modeled and compared for utilization of three different types of biomass feedstock: Straw, bagasse and wood, in order to understand the effects of their composition on supply chain, economics, and environmental factors for ammonia production.

Their study emphasized that GWP will be lowered if biomass is used as the feedstock for ammonia synthesis. Among the three types of biomass used for ammonia synthesis in the study, bagasse has the lowest GWP followed by wood and straw pellets. Among the three different types of biomass, wood has the highest ammonia production rate. With this solution, the discharge of GHG emissions from the use of electricity will be lowered. However, this strategy will decrease the amount of ammonia produced, resulting in an increased output product price.

All variables such as the specific type of biomass, economics, and the environmental profile correlate to a specific location. As reported for the production of a specific amount of ammonia using the same production process, the amount of water depletion when using bagasse is higher compared to using wood as the feedstock.

For example, when using the SMR process for ammonia production, the amount of water depletion by means of bagasse is said to be 2. This total energy is considerably higher compared to conventional fossil fuel-based ammonia production, which is According to Tallaksen and Reese the process requires less fossil energy since the system operates with wind power, resulting in lower GHG emissions when compared to running the system from the grid which was reported as Whereas, Frattini et al.

Both studies agree that ammonia production from renewable energy sources results in lower carbon dioxide emissions. Bicer et al. They concluded: 1 ammonia production from a water electrolyzer powered by biomass and municipal waste offers a reliable alternative for distributed ammonia production facilities and can increase fertilizer production; 2 municipal waste-based ammonia production can be considered as one the most environmentally benign methods among the proposed processes, since it has the lowest abiotic depletion, global warming, and human toxicity values 3 the renewable sources with their improved efficiency are able to lower the overall environmental footprint and can replace the current fossil fuel-based centralized ammonia production facilities.

Frattini et al. Through this study they assessed three scenarios for renewable hydrogen production: 1 biomass gasification, 2 electrolysis of water and 3 biogas reforming. They compared these technologies with the conventional SMR of natural gas. They concluded that ammonia has the capability to be produced through an efficient manner using renewable energy sources, leading to an alternative method of a distributed, efficient, and sustainable ammonia production process.

This results in a decrease in carbon dioxide emissions and costs, and an increase in production output. Moreover, this process allows for storing of renewable energy as a seasonal energy vector which has a high energy density with low emissions.

New configurations have no effect on the amount of primary energy utilized for ammonia synthesis. This demonstrates that applying renewable energy does not limit the efficiency of the process. They made an explicit case for the advantages of electrolytic hydrogen production in comparison to biomass gasification or biogas reformation.

Both studies aim to quantify the costs and advantages of integrating the Haber-Bosch process with a renewable hydrogen feedstock resulting from biomass gasification, electrolysis of water operating by solar, wind, hydropower, nuclear power, and biomass. In summary, both projects investigated the carbon intensity of ammonia production. However, Bicer et al. The LCA study by Tallaksen and Reese on the other hand was more focused on environmental issues rather than raw material depletion.

Another study conducted by Bicer and Dincer highlights the advantages of ammonia utilization in transportation passenger cars and power plants by evaluating different environmental impacts including: GWP, acidification, abiotic depletion, and ozone layer depletion. In this study ammonia is produced using water electrolysis in an electrochemical reactor using molten salt electrolyte powered by wind energy. This also applies to the production of about 0. Both Frattini et al.

Bicer and Dincer also makes an explicit case for replacing conventional fuels with carbon free ammonia, thereby significantly reducing the GHG emissions associated with the transportation and power generation sectors. There is a lack of research on the environmental and economic impact of water usage in the production of ammonia which is assessed in this section.

Many studies have been conducted on sustainable ammonia production and mainly focus on water electrolyzers powered by renewable technologies such as solar and wind. These studies include one conducted by Soloveichk and a series of different processes that was compiled by Wang et al. There is a crucial research gap on environmental and economic aspects of sustainability when assessing water consumption in the production of ammonia in these reviews. In order to operate, these processes require a constant water supply while considering the implications of the increasingly severe worldwide water crisis.

The critical inputs for electrolysis are electricity and deionized water. In general, a water electrolyzer requires pretreated, high purity water for its operation Mehmeti et al. The major implications of water consumption in various hydrogen production processes and the effects associated with water on the environment are important factors that have been assessed in the study conducted by, Mehmeti et al.

Studies conducted by Alcamo et al. However, it must be noted that water scarcity is dependent on local availability. According to Mehmeti et al. Morgan also conducted a techno-economic feasibility study on an ammonia production plant powered by offshore wind. The study reported that for the production of tonnes of ammonia, tonnes of distilled water are required. The ratio of the treated water required per tonne of ammonia excluding the water needed for the cooling tower is approximately 1.

This figure is also reported by Will and Lukas when assessing an ammonia production plant using water electrolysis powered by renewables solar, wind, and hydro energy. This shows that for the production of approximately 1 tonne of ammonia, 2. According to the study conducted by Morgan , a water desalinization system is incorporated into its process for production of purified water required for ammonia synthesis.

The use of desalination systems is energy intensive and detrimental to ocean biodiversity and marine life Peterson, In , the amount of ammonia produced was reported to be million tonnes globally. Based on this data, to produce the same amount of ammonia through water electrolysis, While a water electrolyzer coupled with renewable technologies as discussed above requires high volumes of water for its operation, the conventional ammonia production process, which is SMR coupled with Haber-Bosch processes, is also relatively water intensive requiring approximately 0.

However, this figure is lower than the aforementioned methods for ammonia production. Table 5 shows that SMR coupled with Haber-Bosch process is the most carbon intensive technology with 1.

Water electrolysis is the most water ca. TABLE 5. Key consumption and GHG emissions for renewable and conventional ammonia production technologies to produce 1 tonne of ammonia. Ammonia can play the role of a fuel for energy storage as well as its primary use as the main ingredient for fertilizers, transport fuels, and many other applications. However, sustainable routes for its production are needed.

As hydrogen is the main feedstock for ammonia synthesis, a review of various sustainable hydrogen and ammonia production processes has been carried out.

In addition, an assessment of different studies on the environmental performance of ammonia production through LCA has been conducted. The review of ammonia production technologies shows that current processes are either multistage, energy or carbon intensive, or require significant amounts of water resources to operate. Identifying greener pathways low carbon, low water, and low energy usage for ammonia production is important to ensure food security and its application in energy storage.

After reviewing several studies, there seems to be a lack of focus on processes that aim to reduce the amount of water required for sustainable ammonia production. However, there are a number of studies that have assessed the effect of water usage in different ammonia production processes SMR and water electrolysis by focusing on food security, environmental sustainability, and economics through conducting LCA.

Two mature technologies, SMR and water electrolysis, both coupled with Haber-Bosch and powered by renewable technologies are compared in this study. The former consumes less water while having higher GHG emissions and the latter emits less GHGs with higher water consumption.

Of course, each hydrogen production technology has its pros and cons, the selection of these requires various criteria that would be specific to a particular project and context.

These criteria include environmental impact, efficiency, cost effectiveness, resources and their use, commercial availability and viability, and system integration options e. Additional research is needed in a few key areas of research on the production of ammonia through waste utilization, environmental impacts of water usage for ammonia production and where an ammonia production plant needs to be located, in terms of both availability of feedstock and sustainability accessibility to renewable energy sources such as solar Photovoltaic and wind power, distance from the waste hub to the production plant, etc.

In order to clearly address the problem associated with the reduction of water in ammonia production processes, meta-analysis of various technologies and stages for ammonia production is required. These factors need to be addressed in future studies. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Acar, C. Editor I. Dincer Oshawa: Elsevier , 3— Google Scholar.

Akroum-Amrouche, D. Alcamo, J. Future long-term changes in global water resources driven by socio-economic and climatic changes. Hydrological Sci. Ali, M. Nanostructured photoelectrochemical solar cell for nitrogen reduction using plasmon-enhanced black silicon.

Amar, I. Solid-state electrochemical synthesis of ammonia: A review. Solid State Electrochem. Argun, H. Photo-fermentative hydrogen gas production from dark fermentation effluent of ground wheat solution: Effects of light source and light intensity. Hydrogen Energ. Arora, P. Small-scale ammonia production from biomass: a techno-enviroEconomic perspective. Multi-objective optimization of biomass based ammonia production - potential and perspective in different countries.

Arslan, C. Impact of pH management interval on biohydrogen production from organic fraction of municipal solid wastes by mesophilic thermophilic anaerobic codigestion. Hindawi: BioMed Research International , 1—9. Bicer, Y. Life cycle assessment of ammonia utilization in city transportation and power generation. Comparative life cycle assessment of various ammonia production methods.

Investigation of novel ammonia production options using photoelectrochemical hydrogen. PhD thesis. Bolzonella, D. Recent developments in biohythane production from household food wastes: a review. Brown, T. Later alternative sources of ammonia mineral were discovered.

Guano and saltpeter played valuable roleas strategic commodity. Guano consists of ammonium oxalate and urate, phosphates, as well as some earth salts and impurities. Guano also has a high concentration of nitrates. Saltpeter is the mineral form of potassium nitrate KNO 3. Potassium and other nitrates are of great importance for use in fertilizers, and, historically, gunpowder. Fig: Guano is simply deposits of bird droppings.

The demand and the desire to fix nitrogen to make explosives , as well as fertilizers, led to the development of chemical processes to produce ammonia. During s Fritz Haber and Carl Bosch developed the first practical process to synthesis ammonia from atmospheric nitrogen.

Prior to the discovery of the Haber process, ammonia had been difficult to produce on an industrial scale, and related industries were completely dependent on ammonia minerals. It is estimated that half of the protein within human beings is made of nitrogen that was originally fixed by this process; the remainder was produced by nitrogen fixing bacteria and archaea.

Picture: Fritz Haber and Carl Bosch. Plants require nitrogen to produce this protein. Ammonia is the only viable source of nitrogen for producing large amounts of protein. The nitrogen content of fertilizers improves both the quantity and quality of protein-containing crops. In addition to food production, nitrogen fertilizers are currently used to produce the plants for ethanol fuel. While ammonia can be applied directly to the soil as a liquid or reacted with CO 2 to produce urea NH 2 2 CO fertilizer, a large percentage is converted to nitric acid HNO 3 by the Ostwald Process which uses platinum gauze as a catalyst.

Fig: Urea. The electrolytes comprise the main ionic conducting phase and an additional phase that is attached to the main phase to improve the electrical, mechanical and thermal properties [ 26 ]. As the representative of composite electrolytes, alkali metal carbonate such as LiCO 3 and oxide such as LiAlO 2 and CeO 2 doped with Sm 2 O 3 have shown the expected properties, including oxygen ion, carbonate ion and proton conductivity [ 27 ].

In addition, Amar et al. They obtained an ammonia production rate of 2. There are different materials which can be included in this type of electrolyte. These include perovskites such as cerate and zirconate [ 28 ] , fluorites such as doped zirconia, ceria and thoria , pyrochlores such as calcium doped lanthanum zirconate and other materials including brownmillerite, eulytite and monazite [ 26 ].

By adopting this kind of solid state electrolyte, the ammonia production rate of 3. As an alternative process for ammonia production, a process employing the thermochemical cycle has been developed [ 30 ].

The system consists of two circulated processes: reduction nitrogen activation and steam-hydrolysis ammonia formation. Both reactions are summarized as follows:. Figure 3 shows the schematic diagram of the thermochemical cycle of ammonia production. The primary energy sources are pre-treated and converted to carbon before being fed to the thermochemical cycle process. In the first reduction process reaction 4 , the AlN is produced through the carbothermal reduction of Al 2 O 3 and nitrogen.

Moreover, in the second reaction, which is steam-hydrolysis reaction 5 , the AlN produced in the first reduction process is reacted with steam H 2 O producing Al 2 O 3. The produced Al 2 O 3 from this second reaction is then circulated to the first reduction process.

Detailed reaction kinetics have been analyzed in detail in [ 31 ]. Unlike the Haber—Bosch process, this thermochemical cycle can be carried out at atmospheric pressure and without a catalyst.

The process allows independent reaction control for nitrogen activation reaction 4 and ammonia formation reaction 5. Furthermore, as could be observed from reaction 4 , the system can produce ammonia directly from carbonized material, instead of pure hydrogen.

Therefore, this system is expected to be able to reduce the energy consumption during ammonia production. However, this system has the biggest challenge related to its very high operating temperature, leading to limited heat sources and materials. Various ideas have been suggested for the heat supply, including the utilization of concentrated solar heat. Juangsa and Aziz [ 32 ] have developed an integrated system, consisting of nitrogen production, ammonia production employing the thermochemical cycle and power generation.

In their system, the heat required for reduction is basically covered by heat generated by the combustion of fuel gases produced during ammonia production. In addition, they also stated that the oxidation temperature has a significant role in the performance of the system.

Due to increasing concern related to economic and environmental impacts, efforts to propose and develop an advanced ammonia production system have been carried out intensively. These include both thermochemical and electrochemical processes. Cinti et al. Moreover, the same group [ 11 ] also developed an integrated system covering methane steam reforming and Haber—Bosch process.

They mainly focused on system integration and heat recovery to improve the total energy efficiency. Furthermore, Aziz et al. Their system includes cryogenic nitrogen separation with a single distillation reactor, the Haber—Bosch process and power generation. The produced heat during ammonia synthesis, as well as the purged gas containing a little hydrogen and ammonia , is recovered and utilized for power generation.

In addition, they employed both exergy recovery and process integration in order to realize high energy efficiency [ 35 ]. Other integrated systems for the production of ammonia from various kinds of primary energy sources have been developed. Nurdiawati et al. In their system, the nitrogen separation process is omitted due to the utilization of nitrogen-rich flue gas from the chemical looping. A different system has also been developed by the same group [ 37 ] , with the main difference in hydrothermal gasification and nitrogen production.

Another combined system to convert the agricultural waste from a palm oil mill has also been proposed and evaluated by Ajiwibowo et al. In their system, the supercritical water gasification of blended empty fruit bunch and palm oil mill effluent is combined with syngas chemical looping and Haber—Bosch-based ammonia synthesis.

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Need Help? Membership Categories. Regular or Affiliate Member. Graduate Student Member. Undergraduate Student Member. Benefits Enjoy these benefits no matter which membership you pick. Thank you! Green Chemistry Industrial ammonia production emits more CO 2 than any other chemical-making reaction. Credit: Siemens. The Siemens green ammonia test plant uses wind power to convert hydrogen and nitrogen to ammonia. Ammonia by the numbers Sources: Institute for Industrial Productivity.

Credit: Rong Cai. Nitrogenase is the only enzyme known to reduce N 2 to NH 3 at ambient temperature and pressure. Current process Today, ammonia synthesis starts with generating hydrogen gas from fossil-fuel feedstocks. A reformer turns the feedstocks into a mixture of gases called synthesis gas syngas , which includes hydrogen.

A CO shift converter combines water and the carbon monoxide from syngas to form CO 2 and more hydrogen, and then acid gas removal isolates the hydrogen for ammonia synthesis. This process releases CO 2 at various steps along the way. Credit: Douglas MacFarlane. This device, developed by Douglas MacFarlane and coworkers at Monash University, can convert hydrogen and nitrogen to ammonia inside a cell phone—sized package.