Crude Oil Compatibility Testing - Field Fouling Monitor
New Field Fouling Monitor (FFM)
Fouling in the preheat exchanger network is frequently caused by the precipitation of asphaltenes, often as a result of incompatibility of crude blends or instability of the asphaltenes at elevated temperatures. GE Water & Process Technologies (GE W&PT) has developed a new patented Field Fouling Monitor (FFM) tool to identify and predict potential instabilities of crudes and crude blends.
Heat exchanger network systems are used to recover as much sensible heat as possible from process streams around the CDU by preheating the feedstock prior to entering the furnace. The more heat transferred to the feed in the exchangers, the less energy/fuel is required to heat the crude to the required distillation temperature range. The hottest exchangers have a direct impact on the furnace inlet temperature. Exchangers with the highest heat flux or low flow velocity usually show the highest fouling rates. Fouling is caused by the precipitation of solids materials, both organic and inorganic, present in the feed or formed in the heating process of the crude preheat system.
As the heat duty loss is directly proportional to the normalised furnace inlet temperature (NFIT) decline, compensating for the decline in NFIT requires increased fuel in the furnace, and this consequently contributes to an increase in CO2 emissions. By tracking the CDU furnace fuel demand, CO2 emissions can also be quantified. Fouling in the preheat exchanger network is frequently caused by the precipitation of asphaltenes, often as a result of incompatibility of crude blends or instability of the asphaltenes at elevated temperatures. To assist Refiners to optimise crude blends and minimise the fouling potential in crude preheat exchangers and crude furnaces, GE W&PT has developed their new FFM to identify and predict potential instabilities of crudes and crude blends.
The new FFM functions by conducting an X-Y laser scan of a prepared sample slide, covering a sufficiently large area to ensure a representative analysis. The FFM accurately determines the particle count per surface area and defines the size and distribution of the particles in the sample.
Figure 1: New Field Fouling Monitor Developed by GE W&PT
The FFM allows for on-site crude analysis and compatibility studies to predict the relative fouling potentials of the different crudes and crude blends being processed. By blending the crudes in different ratios and measuring the FFM values, incompatibility and instability of the blend due to asphaltene precipitation is easily identified. When no increase in solids is observed, the blend is considered compatible and stable (see Figures 2 and 3).
Figure 2: Unstable Crude Blend
Figure 3: Stable Crude Blend
Some of the evaluations that can be conducted around the crude unit with the patented FFM device include:
Quality of crude feedstock
Crude compatibility studies in different blend ratios
Fouling potential in crude preheat
Evaluation of tolerance to instability of crude and crude blends to the CDU
Desalter solids removal performance
Performance improvement monitoring and optimisation of specific antifoulant programmes, as part of a holistic crude unit solution
Contact ImproChem for more information on the patented Field Fouling Monitor and advanced solutions for crude unit fouling control.