Haber process


Haber process The process for the direct synthesis of ammonia from and Hj over a catalyst.  [c.198]

This reaction is an undesirable side reaction in the manufacture of hydrogen but utilised as a means of removing traces of carbon monoxide left at the end of the second stage reaction. The gases are passed over a nickel catalyst at 450 K when traces of carbon monoxide form methane. (Methane does not poison the catalyst in the Haber process -carbon monoxide Joes.)  [c.181]

The process is as follows ammonia gas (made by the Haber process) is liquefied under pressure, to freeze out any water, and the anhydrous gas is then passed together with dust-free air through a  [c.238]

Although the left to right reaction is exothermic, hence giving a better equilibrium yield of sulphur trioxide at low temperatures, the reaction is carried out industrially at about 670-720 K. Furthermore, a better yield would be obtained at high pressure, but extra cost of plant does not apparently justify this. Thus the conditions are based on economic rather than theoretical grounds (cf Haber process).  [c.297]

Ammonia (NH3) is the most important commercial compound of nitrogen. It is produced by the Haber Process. Natural gas (methane, CH4) is reacted with steam to produce carbon dioxide and hydrogen gas (H2) in a two step  [c.19]

Industrially, production is either from the Haber process at high pressure  [c.276]

The two types of vessel geometries employed are vertieal and horizontal. In most of the fine ehemieals proeesses the leaves are fitted into vertieal vessels whereas horizontal vessels are used in the heavier process industries sueh as the preparation of sulfur in phosphoric acid plants. The leaves inside horizontal tanks may be positioned either along the tank axis or perpendieular to the axis. In order to utilize the tank volume for maximum filtration area the width of the leaves is graduated so they fit to the eireular eontour of the tank.  [c.197]

It is estimated that each year approximately 150 million tonnes of nitrogen are fixed biologically compared to 120 million tonnes fixed industrially by the Haber process (p. 421). In both cases N2 is converted to NH3, requiring the rupture of the N=N triple bond which has the highest dissociation energy (945.41 kJmol )  [c.1035]

Ammonia Production (Haber Process)  [c.144]

Figure 10.8 presents a variant of the FCC process, the RCC (Residue Catalytic Cracking) capable of processing heavier feedstocks (atmospheric residue or a mixture of atmospheric residue and vacuum distillate) provided that certain restrictions be taken into account (Heinrich et al., 1993).  [c.389]

Running casing is the process by which 40 toot sections of steel pipe are screwed together on the rig floor and lowered into the hole. The bottom two joints will contain a guide shoe, a protective cap which facilitates the downward entry of the casing string through the borehole. Inside the guide shoe is a one way valve which will open when cement / mud is pumped down the casing and is displaced upwards on the outside ot the string. The valve is necessary because the at the end of the cementing process the column of cement slurry filling the annulus will be heavier than the mud inside the casing and U tubing would occur without it. To have a second barrier in the string, a float collar s inserted in the joint above the guide shoe. The float collar also catches the bottom plug and top plug between which the cement slurry is placed. The slurry of  [c.54]

Compared to a dry gas, a wet gas contains a larger fraction of the C2-Cg components, and hence its phase envelope Is moved down and to the right. While the reservoir conditions remain outside the two-phase envelope, so that the reservoir fluid composition remains constant and the gas phase is maintained, the separator conditions are inside the two phase envelope. As the dew point is crossed, the heavier components condense as liquids in the separator. The exact volume percent of liquids which condense depends upon the separator conditions and the spacing of the iso-vol lines for the mixture (the lines of constant liquid percentage shown on the diagram). These heavier components are valuable as light ends of the fractionation range of petroleum, and sell at a premium price. It is usually worthwhile to recover these liquids, and to leave the sales gas as a dry gas (predominantly methane, C ). Note that the term wet gas does not refer to water content, but rather to the gas composition containing more of the heavier hydrocarbons than a dry gas.  [c.102]

Thus the oxidation of light metals such as sodium, calcium, or magnesium follows Eq. VII-31, the low-temperature oxidation of iron follows Eq. VII-29, and the high-temperature oxidation follows Eq. VII-30. The controlling factor seems to be the degree of protection offered by the coating of oxide [160]. If, as in the case of the light metals, the volume of the oxide produced is less than that of the metal consumed, then the oxide tends to be porous and nonprotective, and the rate, consequently, is constant. Evans [160] suggests that the logarithmic equation results when there is discrete mechanical breakdown of the film of product. In the case of the heavier metals, the volume of the oxide produced is greater than that of the metal consumed, and although this tends to give a dense protective coating, if the volume difference is too great, flaking or other forms of mechanical breakdown may occur as a result of the compressional stress produced. There may be more complex behavior. In the case of brass alloyed with tin, corrosion appears first to remove surface Zn, but the accumulated Sn then forms a protective layer [161].  [c.283]

Schinke R and Huber J R 1995 Molecular dynamics in excited electronic states—time-dependent wave packet studies Femtosecond Chemistry Proc. Berlin Conf. Femtosecond Chemistry (Berlin, March 1993) (Weinheim Verlag Chemie)  [c.1090]

Let us consider the formation of sodium chloride from its elements. An energy (enthalpy) diagram (called a Born-Haber cycle) for the reaction of sodium and chlorine is given in Figure 3.7. (As in the energy diagram for the formation of hydrogen chloride, an upward arrow represents an endothermic process and a downward arrow an exothermic process.)  [c.73]

The production by this method was developed originally by Haber after whom the process is now named. Since the reaction is reversible  [c.214]

The production of superphosphate (calcium hydrogenphosphate + calcium sulphate) for fertilisers is the biggest use of sulphuric acid. Second to this is the manufacture of ammonium sulphate from ammonia (by the Haber process). This is also a fertiliser. Other uses are conversion of viscose to cellulose in the manufacture of artificial silk, and so on pickling (removal of oxide) of metals before galvanising or electroplating manufacture of explosives, pigments and dyestuffs, as well as many other chemicals, for example hydrochloric acid refining of petroleum and sulphonation of oils to make detergents and in accumulators.  [c.300]

Ammonia and Hydrogen Production. The earliest route for manufacture of ammonia from nitrogen was the cyanamide process commercialized in Italy in 1906. In this process calcium carbide manufactured from coal was treated with nitrogen at 1000°C to form calcium cyanamide, CaCN2. The cyanamide was hydrolyzed with water affording ammonia and calcium carbonate. Production reached 140,000 t/yr in Germany in 1915, but this process was energy intensive and soon was displaced by the more efficient Bosch-Haber process. This process was developed by BASE and commercialized in 1913 and involves the high pressure reaction of nitrogen and hydrogen over an iron catalyst. Most of the world s hydrogen production is used in ammonia synthesis by the Bosch-Haber process. The hydrogen for ammonia synthesis generally is obtained from synthesis gas produced by steam  [c.164]

In contrast to the large industrial facihties required to produce ammonia economically, some microorganisms are capable of diazotrophy, ie, the abihty to use N2 gas as the sole source of nitrogen for growth. Only prokaryotes, ie, those living things without an organized nucleus (eubacteria, cyanobacteria, archebacteria, and actinomycetes) can perform biological nitrogen fixation, the result of which is the reduction of N2 to ammonia. Such bacteria can be either free-living, such as A tobacter and Clostridium, or symbiotic, like the rhizobia. The latter group, in tight associations with higher leguminous plants, are much more important agriculturally. In exchange for the fixed nitrogen supphed by the bacterium, the legume supphes a protective environment in the form of the root nodule and energy in the form of carbohydrate generated by photosynthesis. Thus renewable solar energy (qv) powers this fertilizer production system. Ammonia fertilizer from the Haber process involves energy costs in production, in transportation to the user, and in storage for what is usually a seasonal industry. As food demands increase and fossil fuel reserves deplete, the exploitation of biological nitrogen fixation becomes more and more attractive as an alternative to commercial fertilizer production. Research in this area ranges from employing molecular genetic techniques to engineer nonlegume cash crops such as com and wheat (see Wheat and other cereal grains) to fix enough N2 for its own requirements (see Genetic engineering), through the increased use of associative symbioses to the development of catalysts based on nitrogenase for N2-reducing processes.  [c.84]

In 1914, while abundant in the atmosphere, natural supplies of nitrogen in manure and in deposits of sodium nitrate were insufficient to meet the demand of war The solution was the Haber process for producing ammonia (NHj) by heating hydrogen and nitrogen gas at high pressure. Hydrogen is obtained by decomposing water (HjO) using heat or electricity. Burning coke and water produces steam, carbon monoxide, and hydrogen (water gas). Water gas reacts with steam and a catalyst to yield more hydrogen, and carbon dioxide which is removed by water dissolution. The mixture of carbon monoxide and hydrogen is the synthesis gas for methanol as shown in Figure 7.2-1. IS ihe source of ammonia and methanol. The hydrogen for ammonia is obtained from the water-gas sliifE reaction. Originally the process used coke from coal or lignite (brown coal), but the.se has been replaced by petroleum products and natural gas.  [c.265]

In the Haber process hydrogen /= and nitrogen are compressed to high pressure say, 50 MPa which is 7,250 psig (pounds per sq. inch gage). If a pipe is 6 in. i.d. and must not be stressed above 200 ksi (thousand pounds/ sq. in.), how thick must the wail be Answer From equation 9.1-2, t = p r/s = 7250 3/200E3 = 0.10 in.  [c.334]

An even more effective homogeneous hydrogenation catalyst is the complex [RhClfPPhsfs] which permits rapid reduction of alkenes, alkynes and other unsaturated compounds in benzene solution at 25°C and 1 atm pressure (p. 1134). The Haber process, which uses iron metal catalysts for the direct synthesis of ammonia from nitrogen and hydrogen at high temperatures and pressures, is a further example (p. 421).  [c.43]

The first industrial synthesis of NH3 from H2 and N2 started up in 1913 ( ) and was known as the Haber-Bosch process. Essentially the same catalyst is used today, with improvements. The catalyst is prepared by fusing Fe304 with a few percent of added K2O and AI2O3 and then heating in a N2-H2 mixture, whereby the iron oxide is reduced to mainly metallic iron. The AI2O3 acts as a structural promoter in ensuring that a high surface area, porous mass is obtained, with the iron present as small crystallites (the manner in which these crystallites form and sinter is important—note Ref. 254). The K2O acts as an electronic promoter, covering most of the internal surface [255] and changing its electronegativity. Poisons include CO2 (probably due to adsorption on the K2O), CO (probably due to adsorption on iron sites), and H2 and O2. Some useful general discussions are those by Ertl [256], Sinfelt [257], and Weinberg et al. [258]. Important older work is that of Emmett (see Ref. 259 and also Ref. 260). Boudart [261] gives a personalized discussion emphasizing Temkin s contributions.  [c.729]


See pages that mention the term Haber process : [c.30]    [c.277]    [c.278]    [c.1214]    [c.19]    [c.138]    [c.373]    [c.88]    [c.1396]    [c.137]    [c.59]    [c.59]    [c.1035]    [c.200]    [c.114]    [c.121]    [c.393]    [c.1101]    [c.1214]    [c.1280]    [c.2698]    [c.303]    [c.196]   
Thermochemical processes (2001) -- [ c.137 ]

Chemistry of Petrochemical Processes (2000) -- [ c.144 ]