A refinery that shared a property line with local residents located and corrected a whining sound that threatened the peace of the community.
The beaches and vast expanse of the southern California coast serve as a drawing card both for recreation and residency. Yet while the sound of the ocean can prove refreshing and soothing, excessive noise from businesses, traffic, construction and industrial operations can disrupt and impact the quality of a community.
Such is the case today with a heavily populated, coastal California town that constantly strives to reduce noise and its impact within its urban environment. The city has a noise ordinance that establishes exterior noise standards by land use. The ordinance regulates a variety of noise generators, with a focus on commercial and heavy industrial operations.
One of the operations that is a source of problems is a major “in-town” refinery. However, the refinery constantly works to reduce its disturbances. In a recent case, they pinpointed and removed a noisy valve.
When founded over 90 years ago, the refinery was distant from heavily populated areas. Today, however, the refinery complex is tightly surrounded by areas consisting of industrial, commercially-zoned, recreational and residential properties.
Land use to the north of the refinery is primarily residential mixed with some commercial and light industrial zoning. Heavy industrial operations with a small parcel of commercial and multiple-family residences dominate the west side of the refinery, while to the east is a golf course along with light commercial and heavy industrial zones. The noise problem was most prevalent, however, at the southern length of the refinery, which borders single-family residences, separated from refining processes only by the width of a four-lane avenue.
The oil refinery is configured to produce large volumes of high-value, cleaner-burning gasoline and diesel fuels designed to meet the air quality standards of the California market. It has a capacity of over 300,000 barrels per day, but operates around the clock so the processing units contribute ambient noise to the surrounding neighborhoods. This noise is particularly troubling to residents who live on that southern border.
THE REFINING PROCESS IN A NUTSHELL
To understand the source of the noise, it is helpful to review the refining process itself. This particular refinery receives crude oil both from a marine terminal and by conventional pipeline. The oil is heated and processed in the crude unit for primary distillation and separation into various components. It is processed first in the crude distillation tower where the oil is fractionated into the following streams:
- Liquid and non-liquid petroleum gas products, such as fuel gas, propane and butane.
- Light liquid products (naphtha), which are further upgraded in the naphtha hydrotreater and platformer for subsequent blending into gasoline.
- Middle distillates (kerosene and diesel), which are produced from the middle of the distillation tower. The kerosene goes to either jet fuel blending, the distillate hydrotreater for ultra-low sulphur diesel (ULSD) production or No. 6 fuel blending. The diesel goes to the distillate hydrotreater for ULSD production.
- The material remaining in the bottom of the crude distillation tower (the material is called atmospheric tower bottoms or ATB) is sent to the vacuum tower for further separation.
The vacuum tower operates at less than atmospheric pressure and fractionates the ATB further. Vacuum gas-oil (VGO) recovered from the vacuum tower is then routed to the ISOMAX unit to be upgraded primarily into naphtha, kerosene and ultra-low sulphur diesel. The residual vacuum tower bottoms (VTB) stream is routed to the visbreaker.
THE OFFENDING UNIT
The ISOMAX unit (a unit that runs a patented and licensed hydrocracking process) uses high heat and pressure to upgrade the VGO through catalytic hydrogenation. This process removes contaminants and produces naphtha for gasoline blending and platformer feed, ULSD and jet fuel. The ISOMAX fractionation bottoms (frac bottoms) are sold as a valuable lubricant feedstock.
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