Concerns over emissions in various operational areas have many oil and gas companies looking for methods to control emissions across the board. One area that has been explored in some sectors is that of covers for tanks and similar uses. One technology, first developed in Denmark for water and wastewater applications, is proving to be significant for Canadian heavy oil producers. The Oil & Gas Duty Hexa-Cover floating cover system offers users improved environmental performance and reduced capital and operating costs.
Hexa-Cover tiles are hexagonal elements with symmetrical ribs on both sides. The ribs make the floating elements distribute themselves naturally and uniformly on the liquid surface without overlapping. The unique design makes them interlock, ensuring that they mechanically constitute a coherent cover.
Since acquiring rights to the technology, Greatario Covers has engaged in research and development to develop a suitable version of the technology with engineered polymers for use in the oil and gas industry, primarily focusing on heavy oil applications such as CHOPS and SAGD. The newly launched Low Density Oil & Gas Duty Model can now be utilized in all conventional crude oils and refined products. Light weight diluent fluids such as pentane, natural gas condensates, naptha or refined products such as gasoline are now all possible thanks to the new cover density of just 0.375 g/cc.
The Alberta Energy Regulator (AER) held hearings recently in the Peace River region, looking into complaints from local residents about odours from the heavy oil operations. Terry Frank, vice president of Sales for Greatario testified at those hearings, saying the Hexa-Cover system would be a good way for operators to deal with the odour concerns and that the Hexa-Cover approach is a much more economical solution for most of what the much more costly VRUs are designed to accomplish.
Canadian Natural Resources Canada Ltd. (CNRL) disclosed in their 2013 Stewardship report that they had, at the time of the report, deployed Hexa-Covers in storage tanks at 1,100 CHOPS sites and were planning to install them in most of their fleet. CNRL reported that the use of the Hexa- Cover system led to operational fuel savings at its CHOPS sites of about 20 percent and the related reduction of GHG emissions.
The covers also prevent or reduce the instance of “foam-overs,” which can occur when solution gas from the heated crude causes a foam that spills out of the top of the tank through the thief hatch or tank vent. That also produces another benefit, which is that producers don’t need to apply as much, or in some cases any, defoaming chemicals to the heavy oil. If they don’t need to use the chemicals, then they don’t need the equipment to spray them which represents a significant cost savings. In fact the OPEX reduction benefits of its covers are just as important as the environmental benefits. In today’s low crude price environment anything that reduces operating costs is appreciated by producers.
There are other benefits being discovered. For example, because the Hexa- Cover system keeps the crude warmer it brings additional cost savings, especially in the winter. By keeping the oil hotter, the trucks that are loading the crude at the CHOPS sites can load it more quickly. They can also unload it faster at the transfer terminal or cleaning facility.