Significance and Use

It has been industry practice to claim the capacity of a skimmer based on the rate of the discharge pump (which are typically rated using water as a test fluid) or other arbitrary methods.

End users need a test methodology that evaluates optimum performance data for planning and selection of equipment.

This test method will assist producers and other stakeholders to verify and accurately report skimmer system performance.

This test method is specifically designed to quantify two key skimmer performance values, to reduce testing costs, and to encourage industry wide performance standardization.

This test method establishes test conditions that will result in a measured nameplate recovery rate and an indication of the combination of test parameters (oil type, viscosity, operating speed) that result in the highest average performance for the tested skimmer system.

This test method will validate the performance of the discharge pump in the skimmer system, under conditions that are typical of a recovery operation. Specifically, this will include a modest imposed head pressure composed of static head and dynamic friction losses due to a specified length of discharge hose.

This test method encourages performance testing using two or more oils for comparison purposes.

Tests shall be conducted under well-documented conditions and generate repeatable results. More detailed testing and collection of skimmer performance is covered under existing standards (for example, Guide F 631 ).

Testing (SL Ross 2007) has shown that, when water is present, recovery performance in slick thicknesses ranging from 50 mm to 75 mm results in values comparable to significantly thicker slicks. This may not be the case with high-rate skimmers in viscous oil, where the rate of oil recovery exceeds the rate at which the slick will flow to the skimmer mechanism.

For skimming systems that include various options for the discharge pump, the test described in this test method may be used to measure the performance of the skimming component of the system. Performance of the pumping component can be measured independently using the same viscosity of oil and the discharge head conditions noted in this test method. The nameplate recovery rate of any specified skimming component and pump combination would be the lesser of the skimming component and the pump.

1. Scope

1.1 This test method defines a method and measurement criteria to quantify the nameplate recovery rate (capacity) of a stationary skimmer system in ideal conditions. If a determination of a skimmer s capabilities in realistic conditions (that is, advancing or waves) is required, testing should be performed according to Guide F 631 or equivalent.

1.2 This test method includes the option of testing to determine recovery efficiency.

1.3 This test method and parameters are intended to provide ideal recovery conditions allowing the skimmer system to operate and collect oil at its maximum possible recovery rate. Given ideal conditions, inherent mechanical and physical attributes of the system become the limiting factors.

1.4 This test method is intended to identify limitations of the skimmer system, such as performance of the skimming mechanism, the flow of oil within the skimmer and sump, the pump characteristics, and typical discharge head conditions.

1.5 It is accepted that the nameplate recovery rate as determined by this test method will not likely be achievable under actual conditions of a spill. The nameplate recovery rate should be used in conjunction with a de-rating factor to account for such issues as changing encounter rate, changes in other recovery conditions, changes in oil properties and slick thickness, number of daylight hours, operator downtime, less than ideal control of skimmer settings, and inclement weather.

1.6 This test method involves the use of specific test oils that may be considered hazardous materials. It is the responsibility of the user of this test method to procure and abide by necessary permits and regulations for the use and disposal of test oil.

1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D971 Test Method for Interfacial Tension of Oil Against Water by the Ring Method

D1298 Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method

D2983 Test Method for Low-Temperature Viscosity of Lubricants Measured by Brookfield Viscometer

D4007 Test Method for Water and Sediment in Crude Oil by the Centrifuge Method (Laboratory Procedure)

F631 Guide for Collecting Skimmer Performance Data in Controlled Environments

Keywords

nameplate; oil; recovery; skimmer;

ICS Code

ICS Number Code 13.020.40 (Pollution, pollution control and conservation)

DOI: 10.1520/F2709-08

ASTM International is a member of CrossRef.

ASTM F2709