Thermtech AS is a Norwegian technology and knowledge company aiming to set the global standard for treatment of cuttings from oil-based and synthetic based drilling mud with their Thermomechanical Cuttings Cleaner (TCC). The method enables a safe and economically sound utilisation of all components in the waste.
Thermal desorption of oil and water
In the TCC the drilling waste is heated to a temperature just high enough to evaporate the oil and water from the waste. All the heat is created in the waste itself by friction, meaning that kinetic energy from the drive unit, typically with an effect of 700kWh, is transformed to thermal energy by means of hammer arms beating into the solid parts of the waste.
The heat transfer is such that a friction dryer is much more efficient than in other thermal desorption technologies. The oil and water will flash evaporate in the reaction chamber, and leave the chamber as vapours after a few seconds. The oil and water will be brought back to a liquid phase in separate condensers for the oil and the water.
Recover base oil
The short retention time in the reaction chamber secures output oil with the same qualities as the original base oil. Re-use of this recovered base oil is industrially proven over years of operations in Norway, Holland, UK and Kazakhstan. Such re-use is not only environmentally friendly, but is also contributes significantly in the business case.
With a price of base oil up to $2 per litre, the value of the recovered oil may well be higher than the total cost of operation. The dried solid can be used for various industrial purposes. It is for example a well-proven substitute for chalk in asphalt.
The capacity of any thermal process depends on the content of the waste, most importantly the water content. The reason being that evaporation of water consumes a lot of energy. The TCC unit is fully able to cope with a waste with high liquid content, but to enhance a maximum capacity and thereby also a minimum energy consumption, the TCC can be a part of a larger set-up with a mechanical dryer in front of the TCC.
A standard TCC will have a capacity of approx. 3t per hour with a solids/water/oil content of 70/15/15 % by weight, but increased to approx 5.5t with a composition of 90/5/5.
Offshore thermal desorption
As environmental legislation tightens, there is a pull to have a complete treatment facility onboard drilling vessels. Due to safety reasons, the small footprint and easy mobility of a TCC, it is probably the only thermal desorption technology that can be operated offshore. One of Thermtech's customers, Total Waste Management Alliance Plc, is offering services with the TCC offshore under the trademark TCC RotoMill. Other service providers are expected to offer offshore treatment services including a TCC during the next six to 12 months.
Global reach
The increased global focus on pollution and efficient recovery of products from waste streams points in the direction of separating this particular waste into its components and thereby enable re-use of the very expensive base oil used during drilling operations.
TCCs are currently operating, both offshore and onshore, all over the world. By the end of 2010 there will be a total of 31 TCC units providing waste treatment services.
Other waste streams
Beside drill cuttings, there are a number of other waste streams from the oil industry that can be handled by a TCC. Thermtech is currently designing a pilot high temperature TCC unit aimed at treating tank bottom sludge, sludge from waste oil pits and other oily waste.