PETREX is an international company with nine exclusive representatives covering over 25 of the worlds largest petroleum and

petrochemical refining, producing, exporting, and importing countries. Approximately one half of PETREX’s business is in the

international market.

Established in 1972, PETREX, Inc. is an environmentally driven company whose two main products are full surface contact aluminum Honeycomb internal floating roofs and oil water separator cover systems. Both products are designed to eliminate the air product interface and therefore the associated evaporation of product and release of hydrocarbons. PETREX has over 40 successful years of experience in the industry.

The PETREX Oil Water Separator Cover System

utilizes epoxy coated aluminum honeycomb

panels that float in direct contact with the liquid.

This eliminates the formation of hazardous

vapors at the source, the air product interface. By

eliminating the formation of hazardous vapors with

our floating panels the separator area will have

greatly reduced operating costs and will be far less

hazardous in both breathing air quality and fire prevention aspects.

The PETREX oil-water separator cover systems, both floating and fixed, meet the requirements of the US Environmental Protection Agency in 40 CFR, Part 61, NESHAPS and 40 CFR, Part 60, QQQ which regulate the storage and control requirements of benzene and

benzene derivatives. PETREX’s goal is to maximize the floating area of each separator.

The vertical travel of the aluminum honeycomb floating cover system is controlled by continuous bottom supports and top stops that are anchored to

the basin walls. The elevation of the supports and stops are determined by the

operating liquid level range and any physical obstruction within the basin. The panels are epoxy coated for additional protection.

A standard 20’ long panel weighs approximately 325 pounds. A crane may be required to lift the panels into the basin.

The floating panels are completely walk-able with the separator in or out of service. A ladder pad can be provided for access to the top side of the panels.

Panels and perimeter seals can be fabricated to fit non-rectangular areas of a separator basin.

Below are before and after photographs of a two bay separator system. PETREX cover systems can be provided with optional wall liner plates, panel grounding systems, and panel access hatches as

shown in the photograph on the right.

PETREX floating cover systems can easily be installed in basins with flight scraper, solids removal, and/or oil skimming systems.

Floating skimmer systems can be provided in PETREX panels.

The panels span the width of each separator basin. The joined panel edges form a double “I” beam at each panel connection for excellent loading characteristics. They are manufactured

with a non-perforated core material that makes minor repairs simple and inexpensive.

The liquid mounted primary with a vapor mounted secondary seal is provided in a single unit that is installed from the top side of the panels. The seals can be installed and/or replaced while the separator is in or out of service. The

overall height of the cover system is only six inches.

PETREX Fixed Covers Existing components of the separator (such as skim pipes, weirs, inlets, pumps, and pipe penetrations) may need to be enclosed with small fixed cover areas.

PETREX fixed covers can be manufactured of carbon steel, stainless steel , or aluminum. Fixed covers are provided with an epoxy coating for additional protection.

The topside of PETREX fixed covers are tread plate that provides a slip resistant surface.

Hatches can be provided on the top side of the fixed covers for inspection and observation.

Deflagration venting can be provided as an additional safety precaution.

Pipe penetrations through the fixed covers can be pre-located and welded in our shop or field located to accommodate existing piping.

PETREX Fixed Covers

Structural supports and wall attachments will be sized to support the weight of existing or new pump units that may be required on the fixed covers

Most pump support openings can be sized to allow the removal of the pump unit from the top side of the fixed cover while the separator is in service and without removing fixed cover deck plates.

A blank plate can be provided to close the pump opening if a pump is to be removed for a period of time for maintenance or replacement.

Depending on the pump style, pump mounting can be such that no electrical connection or motors are exposed to the vapors under the fixed cover during normal operation.

PETREX Aluminum Honeycomb full surface contact Oil-Water Separator Cover Systems function by the simple expedient of eliminating a free liquid surface - the source of evaporation. Fixed

cover systems function by intentionally having a free liquid surface that evaporates into a trapped space. Below is a design comparison between the two types of cover systems.

FLOATING COVER SYSTEM FIXED COVER SYSTEM Operation is entirely passive under floating covers. No vapor recovery or treatment is required for the area under the floating covers.

Hazardous vapors are freely generated and trapped under fixed covers. A vapor recovery system is required to direct the trapped vapors to a control device. Recovered vapor must be treated incurring high operational costs. It may also require inert gas blanketing for safety.

Physically supported by the liquid it is floating on while in service, which provides good support to meet live and dead load requirements.

Is not supported across the free span. A more complex design is required to meet live and dead load requirements.

Panels are contained within existing separator basins below the top of the basin walls and are sheltered from the affects of high winds.

Installed on top of the basin walls and exposed to high winds resulting in more complicated design.

Provides a working platform at a convenient level to access mechanical equipment.

Allows working from top of separator only when in service. Work area could be at a much lower elevation making access to and visibility of equipment difficult.

The removal of a panel exposes only the area under that panel. Any opening releases large amounts of vapors in the explosive range. Inert gas blanketing can be vented resulting in additional cost.

The lack of accumulated vapors reduces the possibility of explosion from a source of ignition. The panels can be grounded as an additional precaution.

The freely formed and trapped vapors present a risk of explosion or fire from a source of ignition such as lightning.

Occupies very little vertical space. May be installed under existing structure or obstructions, seals against vertical walls.

Occupies a vertical space above the product level. May be very difficult to install and enclose an existing structure.

During flooding conditions liquid flows up and through the panel drains. After conditions return to normal, the floating cover resumes functioning without manual attention.

Flood waters are trapped in a structure designed to hold vapor, with internal pressures increasing rapidly. In this case sealing and repairs may be required after flooding.

Below is a photograph of a six bay oil water separator that was equipped with an aluminum fixed cover before a lightning strike caused an explosion.

Below is a photograph of a two bay oil water separator that was equipped with an aluminum fixed cover before a lightning strike caused an explosion and fire.

Other cover system designs use alternative materials of construction for full surface contact cover systems. The most common is a design

constructed of composite / fiberglass material. Below is a design comparison between these two types of cover systems.

PETREX FLOATING COVER SYSTEM

COMPOSITE / FIBERGLASS

COVER SYSTEM The cover system consists of aluminum honeycomb panels that are completely framed with a 6” high aluminum “E” extrusion that spans the basin width. With each panel secured to adjacent panels, multiple double “I” beams are formed spanning the basin providing exceptional structural strength.

The cover system is of non-metallic construction with unknown structural support integral to the panel design.

Panels of aluminum construction will conduct electricity very well. Cover grounding systems can be provided to ground both between individual panels and from the entire cover to an external grounding system.

Constructed of electrically non-conductive composite / fiberglass material.

The all aluminum construction provides very good heat conductivity, which is essential to fire safety. The panels will actually perform as a heat sink in the case of a fire.

Composite / fiberglass material is an insulator and serves to prevent heat conductivity which is vital to good fire safety characteristics.

Composite / Fiberglass Case Study In 1993 a US Gulf Coast refinery was required to cover their oil-water separator system. PETREX provided a quotation to provide our coated aluminum honeycomb panel cover system. The contract was awarded to a competitor who provided a lower priced composite / fiberglass cover system. Several years later, the refiner contacted PETREX requesting that our original quotation be updated as the refinery had experienced a fire at the separator and the composite / fiberglass panels had burned. This system is still in operation today.

In 2000 A US Midwest refinery contacted PETREX to provide replacement seals for an existing composite / fiberglass floating cover system. Upon inspection PETREX determined that the existing covers were exhibiting signs of insufficient buoyancy and declined to provide a price for replacement seals as the additional weight may further restrict the ability of the panels to float. This customer had already purchased a replacement composite / fiberglass cover system for the separator and the materials were on site. The refinery contacted PETREX two weeks later and requested a price to provide an aluminum honeycomb cover system as the original panels in the basin could not be removed without breaking apart. The refinery disposed of the replacement cover materials and PETREX installed our cover system. This system is still in operation today.