6.0 8.0 9.0 7.0 10.0
>5.0
4.0
3.0
3.0 2.0 1.0 4.0 5.0
2.0
1.0
0.0
0.0
0 2 4 6 8 10 12
14 16 18
20 22 24 26
50 28 30 32 34 36 38 40 42 44 46 48
Ammonia (ppm (mass))
Figure 6 Illustration of the effect of varying amounts of HCl and NH 3
171.0
1500 1000 500 2000 2500 3000 4000 3500 6000 5500 5000 4500 8000 7000 7500 6500
170.0
Mass - aqueous (kg/hr) temperature (˚C) (Y2)
169.0
168.0
161.0 164.0 163.0 162.0 165.0 166.0 167.0
0
Water (kg/hr)
Figure 7 An assessment of the required amount of 80°C BFW to be injected into the TPA at 11 BarG and 170°C
Corrosion effects The critical importance of factoring in corrosion effects when implementing beneficial modifications to FCC unit operations cannot be underestimated. Through the application of OLI Systems Ionic Modeling tools, refiners can be empowered to establish a safe and reliable operating envelope and seamlessly execute the management of change process. This approach ensured the continuity and safety of operations while simultaneously optimising the quality of the end product. Additionally, it allowed for the advantageous utilisation of economic incentives associated with processing low-quality oppor- tunity feedstocks. Cristian Spica is an Application Engineer with OLI Systems, Inc. He has 12 years of experience in chemical engineering, including process engineering, modelling and simulation, engineering, design and con- struction, project management, technical support, and training. He holds a degree in chemical engineering from the University of L’ Aquila. Email: cristian.spica@olisystems.com
ensures that the pump operates safely, avoiding the poten- tial for damage caused by cavitation, as shown in Figure 7 . The recommended minimum quantity of wash water under the simulated conditions is 5 TPH, resulting in a post-injection liquid quantity of 2.5 TPH, with a mixing temperature of 163°C. In the absence of a water phase separator, the reflux of TPA into the column will lead to the re-condensation of acidic water on the top packing, where NH 4 Cl will be car- ried back to the packing, initiating a cycle of NH 4 Cl concen- tration in the overhead zone between TPA aspiration and return. Gradually, this cycle will exacerbate the phenomena, eventually leading to column flooding, increased delta pres - sure, a wider gap between HCN and LCO cuts, fractiona- tion problems, and more. For this reason, the refiner implemented a water sepa - ration system in the TPA prior to returning to the column. This system is undoubtedly beneficial and improves the sit - uation by allowing the removal of recirculating water from the system.
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PTQ Q4 2023
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