Simply generating steam at process pressure instead of high pressure to generate power at the top end has a lost opportunity cost. Conversely, steam at ordinary process heating conditions still has a considerable amount of enthalpy that could be used for power generation, so cogeneration has a lost opportunity cost. The high cost of grid power directly affects the bottom of paper industries, and the best option that manufacturers have is to install their own captive power plants, which will operate in cogeneration mode. The capital and operating cost of high-pressure boilers, turbines and generators are substantial and this equipment is typically operated continuously which usually limits self-generated power to large-scale operations.
A typical power generation turbine in a paper mill may have extraction pressures of 11 kg/cm2 and 4 kg/cm2. Typical back pressure maybe 4 kg/cm2. In practice, these pressures are custom designed for each facility. The extracted or exhaust steam is used for process heating, such as drying paper, evaporation, heat for chemical reactions or distillation.
An array of Steam Turbine design and performance capabilities are offered to match desired specifications. The turbine develops the appropriate balance between power and steam to maximize the potential of the co-generation process, thereby minimizing the impact on the environment. Triveni has delivered over 75, optimally designed steam turbo-generators, which not only delivers power but also leads to a consistent steam flow for the process.