Fast Company has received hundreds of ideas about how to fix the gulf oil spill, but this one is getting a bit more attention because it’s author earned masters and Ph.D. degrees from MIT in mechanical engineering and worked in the MIT Fluid Mechanics Laboratory. He started his career at Rockwell International, designing auxiliary power units for the hydraulic systems on the space shuttle. He has been Principal Investigator on several NASA Small Business Innovative Research grants. Below, his two proposals for fixing BP’s leak.
A way to capture all of the flow and stop the spill is outlined in the Figure A below. The advantages of this solution over BP’s planned solution are:
- It will capture all of the leaking oil, not “most” or “much” of the leaking oil.
- It can be implemented now.
- It does not require a new “clean cut.” Cutting the pipe may be undesirable because it will increase the leak at least temporarily.
FIGURE A: Oil Spill Collector
Referring to Figure A above, the leaking oil is pulled from the leaking pipe through a Coupling that is fabricated to conform to the shape of the pipe adjacent to the leak. The oil then pulled through a Flexible Inlet Duct and into the Pump.
The Pump is a key component of this design. The Pump provides the pressure to drive the oil one mile to the surface.
The Pump speed is adjusted based on the pressure measured by the Inlet Pressure Sensor. This pressure sensor measures pressure relative to the local ambient pressure in the sea; it measures the differential or “gauge” pressure. If this inlet pressure is positive, the pressure in the duct is higher than the sea pressure, so the pump is made to work harder to pull in more oil and thereby reduce the inlet pressure. Alternately, this inlet pressure becomes too negative, the pump slows down to bring this pressure back to near zero. In this way the pressure sensor is used to adjust the pump speed appropriately to match the flow being spilled. The speed of the Pump adjusts itself to keep the inlet pressure to a specified pressure set point.
The pressure set point is best set slightly negative so that there is negative pressure (suction) in the inlet Duct. This suction helps secure the coupling onto the leaking pipe. The suction guarantees that any minor leakage in the coupling will result in sea water being drawn in inlet, rather than the oil leaking into the sea. The system works much like a vacuum cleaner with a flexible hose.
Another aspect of the design is that it is better equipped to handle leakage in the coupling. Coupling the new pipe to the leaking pipe should be a straightforward plumbing operation. However, if the joint turns out to be leaky, a small suction pressure inside the pipe will allow sealant to be drawn in to fill in the gaps for an oil-tight seal.
Methane Hydrates formed through the limited contact with sea water during the connection process are pumped out through the pump.
In contrast, all of the systems designed by BP collect only part of the leaking oil. The inlet pressure is positive, which is causes most of the oil to spill into the ocean through the leaky couplings. This was
A more complicated way was developed for the spill when the leak includes too much gas to directly pump. This solution is outlined in Figure B.
FIGURE B: Oil and Gas Spill Collector
The leaking gas-oil mix is pulled from the leaking pipe through a Coupling that is fabricated to conform to the shape of the pipe adjacent to the leak. The oil-gas mix is then pulled through a Flexible Inlet Duct and into the Separator Box. Gravity causes the heavier oil to fall to the bottom and the lighter gas to rise to the top where it is vented to the sea. A Sump Pump draws oil from the bottom of the separator box and pumps it through a pipe to the surface. In contrast, the two solutions BP used pulled the flow from either the top or the side, mixing gas and oil and preventing the devices from effectively siphoning the oil.
The Sump Pump is a key component of this design. The Sump Pump provides the pressure to drive the oil one mile to the surface. The Sump Pump is controlled by a sensor that determines the level of the oil so that it pumps just enough oil to match the leak rate and maintain the set level of oil. In contrast, the current BP collector has no pump or control system and instead leaks most of the oil to the sea through a leaky coupler.
Another key component of this design is the Gas Vent. The gas vent as shown vents just enough gas to equalize the internal pressure of the collection system with the ambient pressure of the sea. This equalized pressure prevents an internal buildup of overpressure that could cause the Coupling to pop off the pipe. This equalized pressure greatly simplifies the most difficult problem, attachment to the leaking pipe. Without a pressure difference across the wall of the inlet duct, the duct can be flexible and facilitate easy connection to the leaking pipe. Without a pressure difference across the coupling, the coupling can be attached to the leaking pipe without the need for a great force to hold the components together.
The gas vent could be made more sophisticated than the simple flap shown. The vent could include an adjustable pressure relief valve, to control the internal pressure to be a positive pressure slightly above ambient or a suction pressure slightly below the ambient pressure. The suction pressure could be used, for example, to help hold the coupling to the leaking pipe through suction. The amount of available suction is determined by the height of the vent above the coupling through the principles of hydrostatics.
The Sump Pump could also be made more sophisticated than the simple device shown. The Sump Pump maintains a fixed liquid oil level in the tank, based on a sump level sensor located in the tank. However, it is not strictly necessary to locate the pump at the tank. The pump may be at the surface to deliver up to 14.7 PSI pumping force, or submerged a short distance below the surface to deliver additional pumping pressure as needed. Submerging the pump provides additional pumping pressure of approximately ½ PSI for each foot under the surface the pump is submerged.
This design can be implemented in many variations. For example, if the natural gas is depleted before the design is implemented, the separator is not needed and the device can be much simpler. The only essential feature is that it pumps the all of the oil to the surface and thereby stops the spill.