Using XRF Analysis to Measure Waste Cooking Oil Grades

Waste cooking oil from fast-food chains, restaurants, and food producers, has become a useful commodity. At present the forecasted growth of the global usage of cooking oil is 3.8% CAGR until 2023. Waste cooking oil is recycled and utilized for a number of purposes, such as industrial burner fuel and additives in manufactured products – but creating biodiesel is the largest use of waste cooking oil.

The demand for biofuel is growing and it is driven by environmental targets for biofuels in transport, particularly in Europe. In the United Kingdom for example, new biofuel targets have been established for the transport sector. These progressive targets start at 4.75% biofuel by volume, and quickly increase every year to 12.4% in 2032.

Recycled cooking oil is assisting in meeting this goal. More than 500 million gallons of waste oil are gathered by professional oil recycling services for reuse every year in the United States, according to the US EPA. Waste cooking oil is required to meet certain specifications to be suitable for conversion into biofuel.

Meeting Tight Specifications for Biodiesel

Automotive fuel, including biofuel blends, must comply with strict sulfur standards, such as BS EN 590 or ASTM D975 and D7467. So decreasing the sulfur level present in diesel is crucial for environmental reasons. To help adhere to these specifications, all feedstock products which are refined to create automotive fuel are required to contain extremely low levels of sulfur, including reprocessed waste cooking oil and plant oil.

When road tankers which contain used cooking oil (UCO) get to the biodiesel refinery, the oil is tested to confirm it is suitable for use. The tankers are refused, or a higher price is imposed to cover the extra processing needed to decrease the sulfur levels if they are too high. Chlorine is another controlled element in UCO. Chlorine found in the fuel can become chloric acid, which is extremely corrosive and can damage process components within a refinery.

The industry standard for chlorine and sulfur level measurements within all petrochemicals is XRF analysis. Waste cooking oil collection companies can utilize XRF to ensure deliveries will meet the set standards. This aids in confirming deliveries are accepted at the biodiesel refinery.

Using XRF to Measure Sulfur Levels in UCO at Collection

Hitachi’s X-Supreme 8000 complies with well-established sulfur standard test methods such as ASTM D4294, ISO8754 and ISO13032. It has the accuracy required to measure sulfur in used cooking oil and it is also easy to use by non-technical operators.

A sample must be prepared before taking the measurement because UCO contains a number of contaminants. Firstly, a small amount of used cooking oil is heated in an oven, secondly the sample is spun in a centrifuge, and lastly the portion is taken to be measured from the top one-third of the centrifuged liquid.

This is placed into a sample cup in the X-Supreme 8000. All the operator then needs to do is enter a sample label on the X-Supreme’s display and press a button to begin the test.

To make it simple to establish if the cooking oil will make the grade, the X-Supreme 8000 can be set up with a pass and fail message. XRF analysis is a quick and easy way to verify if deliveries of waste cooking oil will be accepted when they arrive at the refinery.

Why Use XRF to Analyze Sulfur in Oil?

There are numerous ways you can choose to analyze sulfur in oil, including: UVF, WDXRF, combustion methods and microcoulometry. These techniques have been proven to be less accurate, and often more time consuming and costly to complete.

This information has been sourced, reviewed and adapted from materials provided by Hitachi High-Tech Analytical Science.

For more information on this source, please visit Hitachi High-Tech Analytical Science.