Monday 10 October 2016

Ammonia

Ammonia

The chemical and petrochemical sector is the largest industrial energy consumer. Ammonia production is responsible for about 17% of the energy consumed in this sector. In 2004, the ammonia manufacturing industry consumed 5.6 EJ of fossil fuels, of which 2.7 EJ was for energy and 2.9 EJ for feedstock use.1 Although the energy use per tonne of ammonia has decreased by 30% over the last thirty years, adopting best available technologies (BAT) worldwide can further reduce energy use by 20-25%1, 2 and decrease greenhouse gas emissions by 30%.2


In ammonia production, the type of feedstock used plays a significant role in the amount of energy that is consumed and CO2 produced. The type of technology used is another key factor. The steam reforming of natural gas produces on average 2.1 tCO2/t NH3, while in partial oxidation the emissions are about 3.3 tCO2/t NH3 when fuel oil is used and 4.6 tCO2/t NH3 when coal is used to produce hydrogen.a, b This is followed by the type of technology employed. According to a benchmarking study conducted by the International Fertilizer Industry Association (IFA) in 2008, the average net energy efficiency in 93 ammonia plants was 36.6 GJ/t NH3. The energy efficiency of the best performers (top quartile) ranged between 28 and 33 GJ/t NH3. The Best Practice Technology (BPT) energy use for the top quartile of natural gas-based producers was 32 GJ/t NH3. This indicates that a wide adoption of BPTs can decrease energy use and greenhouse gas emissions by approximately 10 percent. The energy use for Best Available Technology (BAT) is 28 t NH3. Worldwide implementation of BATs would result in 25 percent energy savings and a reduction in greenhouse gas emissions of about 30 percent. 2 Table 1 and 2 below provide information on best practice energy use, BAT energy use and CO2 emission values.
The energy use for ammonia production varies across the world. This is mainly due to the combination of the type of feedstock and technology used in different countries. Considering both the feedstock composition and the technology level, it is estimated that China is 35 percent less efficient than Western Europe, Saudi Arabia and Taiwan. Ammonia production in Japan and Korea is estimated to be 5 percent more efficient than Western Europe. Compared to Western Europe, ammonia production in North America and India is estimated to be 5 percent and 15 percent less energy efficient respectively.5 Table 3 shows the estimated specific energy consumption for ammonia production in 2010 in different regions.
Further information on benchmarks on critical process parameters affecting energy efficiency in Indian plants is available

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