Meanwhile, Sabic U.K. Petrochemicals, Wilton, U.K., is to install a regenerative thermal oxidation (RTO) system on its 400,000 t/y low-density polyethylene plant there (Figure 2).
Figure 2 -- Regenerative thermal oxidizer
The technology is being supplied by AirProtekt, Cambridge, U.K., and includes a Roxitherm RTK 70 RTO manufactured by Lufttechnik Bayreuth (LTB), Goldkronach, Germany, which has installed more than 200 such systems on the continent.
Sabic’s new RTO system is designed to combine very high thermal efficiencies — up to 97% — and minimal operating costs. (For more on RTO, see: http://www.ChemicalProcessing.com/articles/2009/024.html.) It can treat high volumes of exhaust gases and handle exhaust airflow rates up to 73,500 Nm³/h at 50°C. The RTK 70s high-temperature operation is capable of achieving more than 99% VOC destruction efficiency and features a purge system to prevent emissions of untreated VOCs during the valve operating cycle.
“This application…enables us to offer the plant’s main contractor, Simon Carves, a competitively priced project solution with a design flexibility that enabled a large RTO system to be efficiently packaged to maximize the potential of the limited available space,” notes Trevor Lawton, AirProtekt’s managing director.
Since 2000, ExxonMobil, Plano, Texas, has been on a campaign to identify opportunities to improve energy efficiency by 15–20% at its chemical plants and refineries. So far, the company has implemented more than half these opportunities, with associated costs savings of about $750 million per year.
These efforts have reaped a number of energy efficiency awards over the years from both the American Chemistry Council and the Industrial Energy Technology Conference (ITEC).
Its most recent ITEC award is for the operation of cogeneration facilities at the company’s Baytown, Texas, site. These increase energy efficiency at the complex’s refinery, two chemical plants and research center — plus help reduce the region’s overall emission of greenhouse gases, says ExxonMobil (Figure 3).
Figure 3 -- The power of cogeneration
Another company on a long-term campaign is Lyondell, Houston. For six years, it has been pursuing a commitment to improve environmental performance at its facilities in Texas. As an integral part of this, the company is investing in new infrared (IR) camera technology to assist in spotting fugitive emissions, leaks in pipe connections and seals.
The use of IR cameras has enabled it to pinpoint the exact location of leaks that might have remained hidden using traditional fugitive monitoring techniques — particularly for components high in a pipe rack, says Lyondell.
Another major advantage is the ability to detect elusive emissions from corrosion beneath insulation. These vapors often exit at points a considerable distance from the source point but an IR camera easily detects the source by following the trail of the hydrocarbon plume.
As a result, both the identification and repair of fugitive emission sources is much more efficient — good news for both the industry and the environment.