Speaker: Kemal Arsava
Oil spill response is demanding under any circumstances, and Arctic conditions impose additional environmental and logistical challenges. This presentation will focus on two main oil spill clean-up methods:
i) In-situ burning (ISB)
A new In-situ burning (ISB) concept, capable of enhanced combustion of oil slicks in containment booms, is analyzed. The concept is based on the use of immersed thermally conductive objects to transfer heat generated by the combustion back to the liquid fuel through conduction, convection, and radiation to create a feedback loop. The enhanced heat transfer from flame to the fuel helps to sustain a significantly increased burning rate. Six large-scale field experiments were performed at United States Coast Guard (USCG) at Little Sand Island in Mobile Bay, Alabama. Experiments resulted in three major outcomes. i) Increase in the heat transfer from flame to the fuel with the introduction of blanket and coils was the first outcome. Additional heat flux directed to the fuel and the nucleate boiling on blanket promoted a 5 times increase in mass loss rate (MLR). ii) Enhanced burning rate aided in complete combustion of the fuel and reducing quantity of unburned products of combustion. The ratio of carbon monoxide produced per carbon dioxide measured in the optimum configuration was nearly half that of the baseline. iii) The reduction of post burn residue on water due to enhanced heat transfer was the third output. The heat stored in the blanket facilitated an efficient burn of tar. The residue burning efficiency was increased from 63% to 98% due to the presence of blanket and coils.
ii) Mechanical Recovery
a) Oil recovered at cold temperatures has higher viscosity which may limit the distance that it can be pumped. At low temperatures, water
recovered along with the oil may start to freeze within the recovery hose. In addition, if the temperature is lower than the oil’s pour point, the oil may become “semi solid” and lose its flow characteristics. CRREL proposed to utilize the waste heat from generators and power packs used during oil spill mitigation procedures to heat the oil that is being pumped through the recovery hose.
b) Rope mop skimmers provide very efficient oil recovery. However, in low temperature conditions the “mop” can become laden with ice,
which drastically affects its ability to recover oil. A new method to heat the rope mop during operation to prevent or reduce ice accumulationon the mop is developed.
c) CRREL evaluated the viability of mounting a compressed air sourced bubbler to an ROV with the purpose of using the bubbling action o herd an under-ice oil slick towards the desired recovery area. A series of intermediate and large-scale tests are performed with various nozzle types and attachment configurations. Tests explored the maneuverability of an ROV with an active air bubbler, the ability to move the oil trapped out of the undulations under the ice, and the feasibility of controlling the direction of the herded under ice oil slick.
Light lunch will be served.
Promoted event for WPI Civil and Environmental Engineering