KAPP Heat Transfer Engineers, together with UreaKnowHow.com developed The KAPP CO2 Chiller, which cools the feed CO2 temperature without using cold energy sources from the existing ammonia and urea plant. This paper will describe and evaluate three options for The KAPP CO2 CHILLER. All three options lead to extreme short pay back times as will be demonstrated in the paper.
In most urea plants the CO2 compressor is the bottleneck for further capacity increase. In summer conditions the CO2 inlet temperature is typically higher than the design figure. Cooling back this temperature will increase the density and will increase the capacity of the CO2 compressor. Some CO2 chillers make use of cold energy sources like existing the ammonia refrigeration compressor. In summer however many times also these cold energy sources form a bottleneck also.
KAPP are specialists in heat exchanger designs located in Dordrecht, The Netherlands. KAPP and UreaKnowHow.com co-operate targeting the urea market with the innovative idea to cool the CO2 with the NH3 feed, so that no cold energy source will be required. When you like to make use of our idea to cool the CO2 with the NH3 feed and have some doubts about the impact of the higher ammonia temperature or lower CO2 temperature, we suggest to follow the following approach for the final design: Choose a CO2 and NH3 outlet temperature of the chiller at which you feel comfortable (for example choose the minimum temperatures you operate at during the most severe winter (for CO2) and most severe summer (for NH3) conditions and/or choose the design temperatures. Then you do not need to take any risks.
CO2 chillers in urea plants in which the cooling is done by chilled water (via VAM system for example) or by ammonia from the ammonia refrigeration system have numerous references. KAPP can also design and/or supply a CO2 chiller with chilled water or ammonia from the ammonia refrigeration system. Our added value is that KAPP has the know how and expertise to provide an optimum design. For example the delta-P of the KAPP CO2 chiller is only half of the CO2 chiller designed by others. A lower delta-P will provide a higher suction pressure at the inlet of the CO2 compressor and this a higher load and/or lower energy consumption of the turbine leading to even lower pay back times.