TURBODEN ORC ADVANTAGES OVER STEAM
01. HEAT SOURCE FLEXIBILITY
The use of organic working fluids which have a lower boiling point and higher vapor pressure than water, allow ORCs to operate efficiently with significantly lower waste heat temperatures.
The traditional steam Rankine cycle is an efficient option for exhaust streams with high temperatures waste heat sources. At low and medium temperatures, steam cycles become less cost effective, require bulkier equipment and are prone to erosion of the turbine blades due to condensation (lack of sufficient energy to superheat the steam)
02. FOCUS ON CORE ACTIVITY
ORC based heat recovery systems are compact, completely automated, simple to operate and with no additional personnel requirements. The operation of the ORC plant is fully automatic in normal operating conditions as well as in shut down procedures without any need of supervision personnel. In case of fault conditions, the ORC plant will be switched off automatically from the thermal oil circuit (which will be then by-passed) and from the electrical grid.
In contrast with steam based plant where full time supervision by qualified operators is required, ORC plants are designed for automatic and continuous operation and can be operated even by unskilled personnel with weekly operation requirements as low as 3-5 hours.
Turboden ORC units demonstrate an excellent behavior in variable flow and temperature conditions maintaining 90% of the cycle efficiency at 50% load and can operate even at 10% of the nominal load.
In effect, the ORCs level of automation and the ability to easily decouple from, and efficiently adapt to, the primary industrial process allow for complete focus on the core industrial activity
On the contrary, steam based heat recovery systems have often sidetracked the core industrial activity by requiring dedicated qualified personnel and process modifications (as in increasing exhaust gas temperatures) because of difficulties in accommodating temperature fluctuations and a steep drop in efficiency when dealing with reduced loads. Furthermore start stop procedures for steam turbines tend to be complex and lengthy.
03. LOW MAINTENANCE | LONG OPERATIONAL LIFE
Maintenance requirements for ORCs are extremely low both in terms of time and in costs. Unlike steam the working fluid is non-eroding and non-corroding for valve seats tubing and turbine blades allowing for long operational life. Planned maintenance typically occurs once a year for two man-days allowing for continuous plant availability and low costs.
The maintenance of steam systems is complicated and costly, involving steam traps, valves, condensate return pumps, and several different systems for controlling steam and water quality. Steam turbines typically require major overhauls at 5 year intervals.
04. ENVIRONMENTALLY FRIENDLY
Thermal oil based systems are closed loop systems with zero liquid waste.
In contract, steam based systems have considerable environmental issues with the disposal of steam blowdown and condensate streams since in order to reduce corrosion the water in a steam system undergoes chemically treatment.