Q & A > Question Details
What are some of the recent advances in corrosion and fouling control technology that are being applied in the industry? Where in the processing industry are these programmes most effective?
05/07/2011 A: Terry Ross, Maintenance Products Australia, terry@maintenance.net.au
Merus rings are gaining acceptance for corrosion control biofouling and srb reduction.
21/07/2007 A: Scott Bieber, Baker Hughes, scott.bieber@bakerpetrolite.com
Baker Petrolite is having significant success with its proprietary Milestone fouling control technology, which was developed for high severity thermal conversion unit heaters. Milestone is a multi-component fouling control additive solution that effectively interrupts the key fouling mechanisms identified for specific crude oil residual heater operations and feedstock characteristics. These fouling control additives were developed to control heater fouling due to: •Thermal degradation of oils •Asphaltene destabilisation •Catalytic effects of feed metals and equipment surfaces •Precipitation of organic and inorganic solids. These additives have proven effective in independent pilot-scale testing and in commercial applications in thermal conversion units worldwide. Recent applications of the technology in delayed cokers have significantly extended heater run lengths and increased unit throughputs, while reducing the frequency and cost of coil decoking procedures. Refiners are currently achieving at least 10:1 payouts on their Milestone program investments. By controlling heater fouling rates, Milestone programs can significantly improve refinery profitability by: •Increasing thermal conversion unit throughput where unit capacity is heater limited •Allowing the unit to maintain maximum conversion, where heater outlet temperatures are reduced to maintain target throughput during a run •Allowing upstream crude units to process higher rates of lower-cost heavy crude oils •Reducing coil decoking costs •Reducing heater fuel consumption. Customised Milestone fouling control additive solutions are developed using proprietary feedstock characterisation and additive selection and dosage testing protocols. Measured feedstock characteristics are also compared to Baker Petrolite’s extensive database of conversion unit feedstock analytical information, to help predict fouling potential in the unit and to determine the probable impact of candidate chemical solutions on heater fouling. Baker Petrolite engineers apply on-site experience with heater fouling control application technology to ensure implementation of effective fouling control solutions for each unit. Economic benefits provided through application of the technology are calculated and tracked using a proprietary Baker Petrolite heater fouling economic analysis tool.
21/07/2007 A: Eric W Hennings, Stone & Webster Engineering Corporation, eric.hennings@shawgrp.com
Distribution of water wash in processes is often imperfect and can lead to increased corrosion. One area of concern is injection of wash water ahead of parallel heat exchangers. The standard configurations such as “symmetric piping” do not adequately address the distribution. This is confirmed by CFD modelling. Arbitrary increase in water flow does not improve the situation much. Parallel water injection and other details are important in providing the best corrosion protection.
21/07/2007 A: Sam Lordo, Nalco Company, salordo@comcast.net
For corrosion control programs, the newest advances are the application of blended amine neutralisers to limit the potential amine/ammonium-salt formation supported by simulation software. The computer simulations provide the insight into which neutralisers are the best to use on a particular overhead system. Computer simulation software is also being used not only to support the crude unit overhead corrosion control programs, but also for other towers in the refinery and chemical plants. One trend we see in fouling control in the refining industry is that more refiners are relying on expertise to monitor their preheat exchangers, such as with Nalco’s proprietary Monitor simulator. The simulator was developed using the same rigorous calculations as more expensive heat exchanger design software, but was specifically designed for monitoring and economics. Monitor delivers optimum exchanger cleaning cycle time and quantifies the total net savings projected. By outsourcing the monitoring to Nalco, refiners are seeing the monitoring done on a regular basis and energy savings clearly communicated, which allows them to make better cleaning decisions. Refinery process engineers can continue to focus on higher-value projects, while energy savings will still be captured through outsourcing.
21/07/2007 A: Ian Ponton, Foster Wheeler Energy, ian_ponton@fwuk.fwc.com
For fouling, normal practice in heat exchanger design is to control fluid velocities and skin temperatures. Thermal computer programs currently carry out a 3D analysis, providing more accurate prediction of velocities and local skin temperatures, enabling a better prediction of likely fouling. We have also used these programs on existing heat exchangers suffering from fouling problems and have demonstrated that predicted high skin temperatures are in the same locations as the high incidence of fouling. As a result, we have been able to offer design changes to reduce maximum skin temperatures and hence reduce the likelihood of fouling.