Ammonia energy consumption

As can be seen from this analysis, the natural gas feedstock and capital charges amount to over 93% of the total production cost before return on investment. Therefore, energy consumption and capital investment are the key factors in determining ammonia production profitabiUty. 

The main advantages of the Cosorb process over the older copper ammonium salt process are low corrosion rate, abiHty to work in carbon dioxide atmospheres, and low energy consumption. The active CuAlCl C H CH complex is considerably more stable than the cuprous ammonium salt, and solvent toluene losses are much lower than the ammonia losses of the older process (94). 

Figure 8.19. The energy consumption of the ammonia synthesis has decreased steadily and is now comparable with the natural process. (Courtesy of HaldorTopsoe AS.)...

Ammonia synthesis is the second largest chemical process, after the production of sulfuric acid (see also Chapter 1). It accounts for about 1 % of the total human-related energy consumption. Roughly 80 % of the ammonia produced is used for fertilizers (either as liquid ammonia or as more easily handled salts such as ammonium nitrate, ammonium phosphate, etc.) and, as such, ammonia synthesis is indispensable for our society. Other applications of ammonia are nitrogen-containing... 

A minor part of mined fossil fuels is used as a raw material for the chemical industry (e.g., plastics, synthetic fabrics, carbon black, ammonia, and fertilizers). The major part supplies the energy needs for modem society. Fossil fuels supply about 86% of global primary energy consumption (39% oil, 24% coal, and 23% natural gas), providing energy for transportation, electricity generation, and industrial, commercial, and residential uses (El A 2001). Coal, and to a lesser extent oil, combustion leaves a significant amount of solid waste. The treatment of solid waste from fossil fuel combustion is treated in different chapters of this book. In this chapter we focus on air emissions of fossil fuel combustion, and their impact on human health and the environment. 

More than 50% of the heat available in the reformer effluent is recovered and used in the reforming reaction. This results in energy consumption as low as 23.4 to 24.8 MM BTU (lower heating value - LHV) per short ton or 5.5 to 5.9 gigacalories (LHV) per metric ton. These values represent a 5% to 10% reduction in energy consumption relative to a conventional ammonia plant203. 

Energy consumption by the process is estimated to be 29.3 GigaJoules per tonne of ammonia for natural gas feed and 30.1 GigaJoules per tonne of ammonia for naphtha feed16. 

The use of molecular sieve dryers for removal of the remaining carbon oxides and water in the synthesis gas to levels of < 1 ppm levels has gained prominence in low-energy-consumption ammonia plant designs. Instead of molecular sieves so-called knockout drums (high pressure vessels to remove traces of liquids) can be used as well. 

Figure 8. Energy consumption of Kellogg ammonia plant s steam reforming of...

Incorporating some or all of the above mentioned improvements will lead to a considerable reduction of energy consumption of an ammonia plant based on steam reforming of natural gas or naphtha. The actual plant design will depend on the project particulars and feed and utility price structure. 

Application To produce ammonia from natural gas, LNG, LPG or naphtha. Other hydrocarbons—coal, oil, residues or methanol purge gas— are possible feedstocks with an adapted front-end. The process uses conventional steam reforming synthesis gas generation (front-end) and a medium-pressure (MP) ammonia synthesis loop. It is optimized with respect to low energy consumption and maximum reliability. The largest single-train plant built by Uhde with a conventional synthesis has a nameplate capacity of 2,000 metric tons per day (mtpd). For higher capacities refer to Uhde Dual Pressure Process. 

Effluent vapors are cooled by ammonia refrigeration (13) and unreacted gases are recycled. Anhydrous liquid ammonia is condensed and separated (14) from the effluent. New energy-efficient and cost-effective designs are in operation with energy consumption of less than 25 MMBtu (LHV)/short-ton, with about 10% capital cost savings over the conventional process. 

Kellogg Brown Root Ammonia Hydrocarbons/natural gas naphtha Extremely low energy consumption cost-effective 175 1996... 

Of the world energy consumption, 1.6% is used for the production of ammonia. In 2000, 108 megatons of ammonia were produced. About 85% is used for fertilizer production as urea, which accounts for 40% of the fertilizer production, and... 

Table 36. Development of ilie nei energy consumption of natural gas based steam reforming ammonia plants (rea plant data) in GJ/t NH ...

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