Siemens Helps Navajo Refining Company Meet NSPS Subpart QQQ, Clean Fuels Emissions Standards

Artesia, NM - Siemens (formerly USFilter) is providing the Navajo Refining Company's refinery in Artesia, N.M., with API oil/water separators, granular activated carbon adsorber systems, multi-media filters and packed bed softeners to meet a number of industry regulations.

To comply with a 2002 federal consent decree, the refinery had to modify or replace its two in-ground API separators. In addition to meeting NSPS Subpart QQQ emissions standards, the separators had to be easy to maintain and able to handle flowrate variations.

Siemens and engineering firm CH2M Hill of Houston helped Navajo Refining evaluate two options that would meet the consent decree requirements. One included installing a liner inside the existing API basins to prevent leaking. The other option included replacing the existing in-ground units with new, above-ground, steel tank units.

"We appreciated having a number of options that would allow us to comply with the consent decree in a timely and cost-effective manner," says Navajo Refining's Gary Davis, mechanical engineer and project manager at the Artesia refinery.

Navajo Refining opted to install two above-ground, steel tank API separators from Siemens Envirex Products. Each separator can effectively process a maximum hydraulic flowrate of 600 gpm, easily meeting Navajo's needs for oil/water separation. The units were completely shop-fabricated and finish-painted prior to shipment, minimizing field installation time and expense. The above-grade units also provide positive leak detection and vapor containment, more effective sludge and oil removal, and easy routine maintenance. Granular activated carbon systems from Siemens Westates Carbon adsorb VOCs in the off-gas from the covered units. The complete system came online in winter 2003.

"Siemens' design met all of the factors we were considering in a system," says Davis. "The system meets the consent decree requirements, and is cost-effective, safe and easy to maintain."

The Artesia refinery has also taken steps to upgrade the quality of its boiler feedwater by adding multi-media filters and packed bed softeners from Siemens to its existing RO system to increase the system's capacity (now 900 gpm) and to produce higher quality effluent (<0.5 ppm CaCO3). The upgrades were necessary to meet the requirements of the refinery's new 650-lb steam boiler in the plant.

The filters came online in summer 2003. They provide better pretreatment to the refinery's RO units, tripling or quadrupling the RO pre-filters' life and eliminating their costly, daily replacement. RO membranes also require cleaning less frequently. And to meet the new boiler's hardness specifications, Siemens added packed bed softeners behind the RO system.

Reject water from the RO system, collected in a new storage tank, is used as backwash water for the multi-media filters. This helps the refinery conserve water and minimize wastewater handling.

"Siemens recommended the best RO system configuration that integrated as much of the existing equipment as possible," says Navajo Refining's Davis. "This produced the desired results while minimizing capital investment."

SOURCE: Siemens Energy, Inc. - Water Solutions