Haber-Bosch Process Alternatives

Haber-Bosch Process AlternativesShould resources be invested in searching for an alternative to the Haber-Bosch process.IntroductionAmmonias ongoing consumption in the universe of discourse is startling. The proceeds of ammonium hydroxide (NH3) was the turn of the 20th vitamin C, a startling breakthrough in thoroughgoing chemistry for the world to stand in astonishment. Two scientist Fritz Haber and Carl Bosch, made this breakthrough through the chemical procedure called the Haber-Bosch Process, (N2+ 3 H2 2 NH3.) However they werent the first to try the deduction of ammonium hydroxide from its elements (www.nobelprize.org, 1920.) prior to the discovery of synthetic ammonium hydroxide and long before the commercial application of it, early farmers knew that certain properties of carbon based by- harvests which led to human waste organism scattered in Chinese farmlands, grinding of skeletons in Europe and the exploitation of Perus readily-available guano, due to its natural no rthwardous compounds, and the discovery of Nitrogen Fixation Processes (www.firt.org, 2012.) The drive for Ammonia was directly think to the worlds survival, the fixed nitrogen from the air is an incredible and needed ingredient for fertilizing. Many principles of chemical and highpressure processes were discovered and expended for the optimisation of the know nitrogen reversion process. Industries in the 19th and 20th ampere-second saw the ongoing need for nitrogen and turned to their already in use factories for producing combust to use the by-product of coking, ammonia sulphate. This along with the previously mentioned methods was how ammonia was haved pre-Haber-Bosch Process. From these early discoveries evidence hind end be seen as to why the Haber Bosch process is the best charge of producing ammonia for the growing world. Two more scientists by the name of Priestly and Cavendish used electrical sparks in the air to produce nitrates, make by profligacy the oxides of nitrogen to form alkalis. Nitrogen Fixation, fixating Nitration as calcium cynamide proved evasive for commercial use, but later proved useful for the production of chemicals requiring the cynamide configuration. There were legion(predicate) another(prenominal) process ect. Thermal Processing, cyanide formation, aluminium nitride formation and the slow process of decomposing to ammonia were deemed to elusive for sustainability due to the scarce amount of chemical components for the organic production to be made, issuanceing in to high of cost. With Habers-Bosch large-scale catalytic synthesis of ammonia from elemental hydrogen and nitrogen mishandle which had reactants that were inexpensive (Hydrogen, Nitrogen and exhort as a throttle.) Using high pressure (5000c) alongside high pressure (150-200 atm), the process involved forcing almost completely unreactive gaseous nitrogen and hydrogen to wealthy person the product of Ammonia. This high-energy process has undergone exten sive modifications in the 21st century which goes on to prove that resources should not be devoted in the search for an alternative to the currently used Haber-Bosch process because the structure of the process is the most balanced of the mentioned processes of making ammonia sluice in the 21st century with a need of 150 million metric tonnes of ammonia (Chemical and Engineering News, 1996) 80% of which is used in agriculture where 48% of the resulting produce is responsible for the worlds ongoing consumption, however there are a few methods that give an idea for very good alternatives that could replace Haber-Bosch, but would not be as efficient.Discussion on MethodsWhat has made the Haber Bosch process so great is its low cost and readily available materials as seen in this method, this however has been as previously mentioned modified many times since Habers workAmmonia synthesis from nitrogen and hydrogen, a reversible reply is as follows(1)And the sense of equilibrium agel ess is(2)(www.ias.ac.in, 2012)From our understanding of organic chemistry we can see that production of ammonia is a exothermic reaction with a exponential amount of heat released. As previously mentioned the reaction is reversible, the forward reaction being ammonia synthesis, and the reverse reaction being ammonia decomposition. The return of the volume derives from the decrease in the morsel of moles of gas from the equations, two and one. With the use of Le Chateliers Principle (See appendix one), from this it can be seen that by increasing the pressure in the reaction causes the equilibrium to invoke to the sort out resulting in a high yield of ammonia produce since there is a pressure drop accompanying the transformation the decrease in the temperature wherefore as well as causes the equilibrium position to move to the right again resulting in a higher yield of ammonia since the reaction is exothermic as previously mentioned. Figures 1A and B show the effect of tempera ture and pressure on the equilibrium mole carve up of ammonia. It can be seen that the ammonia mole fraction decreases as the temperature increased just as the pressure increases.Figure one. (A is the mole fraction of ammonia in the state of equilibrium at varying temperatures to result in a given value of pressure. B is difference pressures at fixed values of temperature in Kelvin, data supplied by www.ChemWiki.orgTemperature (K)Pressure (Atm)The conclusion then that ammonia synthesis according to the first equation is an equilibrium reaction that is favoured by low temperature and high pressure which. The reaction does not proceed at ambient temperature because nitrogen requires a lot of activation energy for the dissociation to happen (www.Topsoe.com). In the gas phase of the reaction, the dissociation occurs only at well-nigh 3000C (ChemWiki.com). Looking at the hydrogen molecule in the reaction, which has a weaker molecular bond, only dissociates markedly happened at temperatu res above 1000C (ChemWiki.com, 2012). Which shows that the reaction cannot be per create at lower temperature because it needs high activation energy to happen, if there was an increase in the temperature with a enough level, the reverse reaction predominates (www. http//abacus.bates.edu/, 2010). This is where scientist heady to have the role of the iron gas come in. Figure two below shows the energy profiles for ammonia synthesis in the absence and presence of the catalyst. The hydrogen and nitrogen molecules lose their translational ability to be startle to the catalyst surface. This reduces the activation energy dramatically and makes the forward reaction go faster, which makes sense to us because catalyst cant do nothing else but speed the reaction up. Other minor components of the catalyst includecalciumandaluminium oxides, which are there to support the hygroscopic iron catalyst and help it maintain its surface area over time, andpotassium, which increases theelectrondensi ty of the catalyst and so improves its activity (ChemWiki.com, 2012). This means that scientist can rid the need for exceedingly high temperature conditions, a problem Haber encounted while trying to find commercial success. Something for us to know it the use of lower temperature reaction conditions means there is special(a) reverse reaction which is energy saving as well, this reinforces the idea of the Haber-Bosch Process being the best there is. For industrial use however, there is still a need for reasonably high temperatures (250400C) to dissociate the N2 and H2.(Figure two, the effect of catalyst on the activation energy). Supplied by www.Chemguide.uk.Now that we know the advantages of the current Haber Bosch Process, we can tone of voice into how carbon-free ammonia comes into the world. Licht wrote a paper on the two current chemical reactions that are now used most widely in ammonia synthesisCH4+ 2H2O4H2+ CO2N2+ 3H22NH3These wont be explained because they already have previously.3CH4+ 6H2O +4 N2 3CO2+8NH3Licht wrote of a proposal for the use of ammonia as a fuel for automobiles. Although Licht did not specify the products of the ammonia oxidation, it looked into the surmise that this fuel cell might prove reversible in the case where a product was nitrogen gas, which looks into the fixation of Nitrogen, an electrochemical path to ammonia. However scientist need to overcome the extreme stability of the nitrogen-nitrogen bond in N2gas, nitrogen fixation always requires the need of gas with a metallic element (www.theenergycollective.com, 2012), which in biological ashess the metal in question is molybdenum (as well as the used iron as the catalyst), making molybdenum, along with iodine, the only elements in the periodic table that are essential to this project.Haber he speculated that there was a better catalyst, uranium which we will look at later.A metal catalyst is required in the electrochemical process as stated, in this process the catalyst is iron, but in this case it is necessary that the iron, present as an oxide in the process, be in the form of nanoparticles suspended in molten alkali hydroxides, where future research can be done on the use of other molten oxides, notably, cesium hydroxide, which may prove superior however the variables in the process with respect to temperature, operating voltage, current and the physical nature electrodes will too need to be detailed in research before this can happen. (www.atomicinsight.com,2012). For this processto happen a eutectic melting mixture of KOH and NaOH, potassium and sodium hydroxides respectively the authors explored besides the use of other molten oxides, notably, cesium hydroxide, which may prove as a better source for the process. These hydroxides are only molten at higher temperatures, and steam and air or pure nitrogen gas are bubbled through the molten hydroxides ( in the case of air, carbon dioxide, meaning that with the removal of this gas from the air would be a side benefit of the process, a benefit to the Haber-Bosch process.)The precise stoichiometry of the reaction varies with the conditions, but one form of reaction mentioned by the authors, this done through a controlled environment, is thisN2+ 10H2O 2NH3+ 5O2+ 7H2Both pure oxygen and hydrogen are important to the reaction, and goes to show that the reaction offers many potential synergies for the benefit of the scientist. The gases on the right side are not produced as an explosive mixture, because ammonia and hydrogen are formed on one side of the cell, at the cathode, whereas the oxygen is formed at the anode (www.atomicinsight.com).The mixture of cathodic gases, ammonia and hydrogen in the reaction, are easily separated by compression as Lecht found. The overall electrochemical faculty is quite high compared to other attempts at the electrochemical reduction of nitrogen to ammonia gas, which is around 46%, an efficiency that may well be emulous with Haber-Bosch proce ss ammonia synthesis, however this does not include the heat penalty associated with melting the alkali metal hydroxides and keeping them molten which is the reason nitrogen fixation was proved a commercial disaster when Haber was working, where 38% of the land would be needed and the cost being severely higher, Habers process uses only 14% of the land to produce ammonia.What else could aid in the Haber-Bosches super process? A better catalyst. Haber sought for a better catalyst in the 20th century with investigations into uranium. With an understanding of the activity of the key component of the Haber-Bosch process which is the catalyst, could help to better the industrial nitrogen fixation still further from what we previously discussed and remove the need for high temperatures and pressures.Ruthenium, osmium, uranium and cobalt-molybdenum can all catalyse the Haber-Bosch process (ChemWiki.com, 2012), but iron catalysts are cheap. Its the most commonly used catalyst which was dev elop more than a century ago and is a potassium-doped iron catalyst. A soluble version of such a catalyst might be even more efficient because it could overcome the rate-limiting step of nitrogen dissociation from a solid catalyst surface, which was demonstrated before. Scientist have found that soluble iron catalysts have proven ineffective for the process in its need to be reducing the N-N triple bond as seen in figure three and also cannot produce large amounts of ammonia for commercial use. Germany has developed a molecular iron complex that can react with(Figure three, The N-N Triple bond, a problem that persist in the formation of an improved haber-bosch process).nitrogen gas in the presence of a potassium reducing agent to generate a complex containing two nitrides bound to the iron and potassium cations which contain a mixed iron (2+/3+) nitride.Germany suggests that the formation of this developed core structure has three iron atoms working in concert to break the dinitroge n triple bond through a six-electron reduction (NewScientist.com, 2014). The resulting nitride of the reaction then reacts with hydrogen gas to generate a high yield of the product ammonia. Unfortunately, this process leads to the use of the iron and so is not catalytic, a problem for the process as it reduces the yield on ammonia because with an absence of a catalyst the reaction is so slow that virtually no reaction happens in a reasonable time (ChemWiki.com, 2012). The catalyst ensures that the reaction is fast enough for a dynamic equilibrium to be set up within the very short time that the gases are actually in the reactor. Germanys work on the core provides important clues as to precisely how nitrogen cleavage and N-H bond formation occurs, which might allow them to build a complex that does work catalytically in solution, something that can be further investigated in the future. This is great because it means the Haber-Bosch Process can be simplified and eventually bring a gr eater yield of product, seeing the growth of ammonia grow in the world.ConclusionThrough economic situations, the Haber-Bosch Process is the most essential to the world, however its also the most relevant in terms of the future. Nitrogen Fixation as we looked at can potentially be a competitor to the Haber-Boch Process, due to its overall electrochemical efficiency which as stated is quite high in comparison to other attempts at the electrochemical reduction of nitrogen to ammonia gas, it is around 46%, an efficiency that may well be competitive with Haber-Bosch process ammonia synthesis. Unfortunately there is no process being examine in thermodynamics to reduce the heat loss from the process, ChemGuide.uk states that A 46% increase is substantial for the future of Ammonia production, but heat loss is an issue for it that so far, cant be reduced with what we know today.The next thing we looked at was the catalyst in the current Haber-Bosch Process. Haber dwelled into Uranium but O.K. out of the idea because of the money, however with the advance we discussed in the study on catalytic effects its clear and hypothesises that there is a high possibility that in the future Ruthenium, osmium, uranium and cobalt-molybdenum can all be used in the synthesis of ammonia with a high yield in produce, which is being investigated currently. Advances in the Haber-Bosch Process are our best approach for the future, scientifically and economically, that is until thermodynamics are better understood.AppendixSummary of Le Chateliers Principle by www.ChemWiki.ucdavis.edu(1) If the submersion of a reactant is increased, the equilibrium position shifts to use up the added reactants by producing more products.(2) For gaseous reactions, gas pressure is related to the number of gas particles in the system more gas particles means more gas pressure. Consider a reaction which is accompanied by decrease in number of moles, such as, ammonia synthesis (equation one). Increasing the pr essure on this equilibrium system will result in the equilibrium position shifting to reduce the pressure, that is, to the side that has the least number of gas particles.(3) In an endothermic reaction, energy can be considered as a reactant of the reaction while in an exothermic reaction, energy can be considered as a product of the reaction. Consider an exothermic reaction which is accompanied by release of heat, such as ammonia synthesis (equation one). minify the temperature of this equilibrium system (which result in taking the heat away) will result in the equilibrium position shifting to increase the temperature (producing more heat), that is, to shift the equilibrium position to the right.