(113a) Condenser Design Performance Evaluation Under Dynamic Fouling Conditions with Hybrid-AI Digital Twins: An Industrial Case Study.
AIChE Spring Meeting and Global Congress on Process Safety
2024
2024 Spring Meeting and 20th Global Congress on Process Safety
Topical 11: 3rd Topical Conference on Heat Exchangers
Heat Exchanger Fouling Mitigation
Tuesday, March 26, 2024 - 1:30pm to 2:00pm
Evaluating the expected performance of different heat exchanger designs once installed in the field can be challenging as a result of the wide variety of conditions they will encounter. Varying conditions include the inlet conditions of temperature, flowrate and pressure, but also the build-up of fouling over time, which will gradually degrade both the thermal and hydraulic performance of the equipment.
In the design and rating stages, the expected performance is normally assessed for selected cases, such as normal operation and turndown inlet conditions; and clean conditions and with standard fouling factors on both sides. Assessing other conditions is possible with standard design software, but becomes a quite tedious and time consuming activity.
In this context, Digital Twins capable of running dynamic simulations of process units represent a powerful alternative to screen a very wide range of conditions (both operational and fouling) to provide a map for the expected performance of heat exchangers. Not only that, once the Twin is set up, it can also be used to assess potential optimisation options, such as the use of bypasses, flow splits or cleaning scheduling. In cases where historical data is available for the service to study, it is even possible to evaluate the performance of different design using the actual plant conditions. In this way, the engineer can obtain all the information required to make the right decision and prepare for actual operation with much less effort.
In this work, an industrial case study is presented that focuses on a propane condenser in a refinery. Two options were considered to replace the old heat exchanger: 1) a new exchanger equipped with finned tubes, specially designed for this service but entailing relatively large capital investment; 2) a readily available heat exchanger with plain tubes which would require a minimum investment. A digital twin was setup for the case study and used to assess both options over a wide range of inlet conditions and gradual fouling build-up. The results showed that the less expensive option 2) could only be used for a narrow range of flowrate conditions and would, additionally, require frequent maintenance; option 1), on the other hand, would be expected to cope with the duty requirements over the entire range of expected conditions and even compensate for fouling build up over a substantial period of time without cleaning.