| There was lot of CO2exists in the shift gas in the synthetic ammonia plant, no matter what they used natural gas or coal as raw material. The more hydrocarbon was used, the more CO2exists in the shift gas. There will be less CO2exists in the shift gas when natural gas or naphtha was used as raw material. The percent of CO2in the shift gas was about15～20%. That means there would get about1.1～1.6tons CO2when1ton synthetic ammonia was produced. CO2need to be removed from the shift gas. Otherwise, the energy of the compressor will be wasted and the catalyst of synthetic system will be made poisoning. Moreover, the pure CO2was raw material which ccn be used to produce sodium carbonate or urea. The process which was used to remove CO2from the shift gas and regenerate the pure CO2from rich solution was called traditionally decarbonization section.In these days, the percent of CO2of decontaminate gas is less than0.1%in the large-ssized synthetic ammonia plant. It will overload the process of methanation and increase the percent of inert gas of the synthetic gas in the synthetic system if the percent of CO2is more than0.1%. At the same time, the purity of CO2which recovered from rich solution should be more than98.5%in order to produce urea.Decarbonization section usually means purification post in traditional large-ssized synthetic ammonia plant in now days. The energy consumption of decarbonization section is about10%of total energy consumption. It is very important to decrease the energy consumption of decarbonization section. The decarbonization process flow which consume lower energy consumption have been used in some synthetic ammonia plants newly built in overseas. Traditionally, an absorption tower and a regeneration tower and some auxiliary equipment were composed of decarbonization process flow. The difference between various decarbonization process flow was mainly found by the auxiliary equipment.Rotating packed bed(RPB), or Higee, is a new-style chemical process equipment which can be used to intensify mass-transfer, separation and reaction. There was widest application in the chemical industry. Compare with the traditional mass-transfer equipment, it is a high efficiency, small volume, simple operation equipment. Presently, it is widely used in the chemical engineering, pharmaceutical industry, environment protection, nano-material production and the gas-liquid-solid separation process.Tests for Removal of CO2with a high gravity technology were carried out by using the mixture of N2and CO2to simulate the shift gas and Benfield solution as the absorbent. Influence of experimental conditions including reaction temperature, pressure, high gravity level and the gas/liquid ratio on the outlet CO2concentration was investigated. Results indicated that the outlet CO2concentration increased first and decreased subsequently with an increasing temperature and high gravity level, while the outlet CO2concentration decreased with increasing in pressure. It was also found that with a certain liquid flow rate the outlet CO2concentration increased with increasing in gas/liquid ratio. Experimental results of rich solution regeneration which used RPB as the main recycled equipment were carried out that decarbonization effect is better than the traditional regeneration towers’. Under the same conditions the lowest percent of potassium bicarbonate of lean solution regenerated is7%, while the lowest percent of potassium bicarbonate is12%in the present technology. In a world, Rotating Packed Bed could be used as the main equipment to remove the CO2from the shift gas and regenerate the rich solution. What we are going to introduce is Rotating Packed Bed which is used to replace the commonly used Packed Tower. With less investment, smaller volume, easier operation, the Rating Packed Bed will be widely used to replace the traditional packed bed in decarbonizing unit of chemical industry. |
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