Cost efficient process for coal-based power plants

The path to development is paved with a continuous need for power to fuel growth. The good news is that both governments and industries are conscious of this and are aligned to address this issue – the governments with stringent regulations and the industry responding with clean technologies. Coal-fired thermal plants have seen some environmental concerns. The flip side is that coal-fired plants also throws most difficult challenges for innovation in clean technologies and for producing cheaper power. Tata Consulting Engineers (TCE) has flashed the spark of innovation yet again to bring sustainable solutions to its customers, especially in coal-fired thermal power plants. The Company hit upon a process innovation in Flue Gas Desulphurization pertaining to coastal-based power plant.

What is FGD

Flue Gas Desulphurization(FGD) is a clean technology system that separates the sulphur dioxide from the exhaust flue gas of coal-fired thermal power plants. Typically, these systems require sea water or chemicals to absorb the sulphur dioxide. Thus FGDs help reduce the SOX emissions to almost 90 to 95% % from the flue gas exhaust and maintain the specified Ground level concentration of SOx within the norms stipulated by various national ambient air emission standards. The extent of regulation for inclusion of FGD systems in fossil-fired power plants varies in different countries across the world. Inland plants typically use chemicals (limestone or other chemicals) to absorb sulphur dioxide, whereas, coastal-based power plants are best benefitted by FGD systems that use sea water. This is because sea water's inherent natural property is conducive to absorption of sulphur dioxide. However, such sea water based FGDs require significant amount of sea water and large water intake systems.

Problems and innovative solutions

The commissioning of a power plant whether captive or standalone come with a host of compliance requirements. This is especially true for coal-based power plants. Tata Consulting Engineers successfully retrofitted an FGD system to a completed thermal power plant. This was a breakthrough solution, as the company had to create an innovative process to mange this. Retrofitting FGD systems to an existing facility has many angles to it - the topography of the plant site, the original design that will have to be modified to accommodate the FGD systems' requirements, the additional facility requirements to operate the FGD systems and most important of all, additional capex burden, project commissioning delays and the resultant project cost over-run. This was the trigger on hand for the Tata Consulting Engineers' team to put on the innovation hat. They put their heads together to create an innovative solution for retrofitting a sea water based FGD system, at minimal time and optimal cost benefit. With a window of twenty-four months, the FGD system was retrofitted and the plant was ready to go on stream completely compliant to environment norms. The process innovation opens up a plethora of opportunities in making coastal-based thermal power plants clean, efficient and environmentally compliant.

Options available for retrofitting of the FGD systems

Retro-fitting a conventional FGD system in a coastal based power plant imposes phenomenal cost escalation and requires time. The use of chemical based FGD is not relevant to coastal-based power plants as the economic advantage of using seawater in coastal-based plants will be lost. The new process innovation provides a solution that is cost efficient in its design and most of all the waste water management is optimal.

The process recommended is a first of its kind with no past references. The new process has implications on inherent systems when the FGD system is being retrofitted. With some modifications , Tata Consulting Engineers successfully implemented the innovative process within 24 months, ensuring huge cost benefits, time savings in plant commissioning, curtailing of project cost escalations and environmental compliances. This also helps in reducing the carbon foot print significantly, when compared to conventional FGD systems.Savings in Capex due to implementation of the innovative process in fitting FGD systems would be to the order of 10 to 20 % and expected savings in Opex would be to the tune of 10 to 50 % depending upon the peculiarities of sites and the projects.

The story of retrofitting FGD systems has many sequels to it. Tata Consulting Engineers' innovative process (economical and environmentally friendly) in FGD systems can be effectively applied to Greenfield, Brownfield and existing coastal -based power plants. Current regulatory compliance mechanisms are more stringent. Presently all countries do not mandate FGD systems in power plants. However, with a greater focus on clean power generation, it is expected that FGD systems would soon be mandated for all coal/oil -fired thermal power plants. The company has filed an application for patenting this technology process.

Tata Consulting Engineers Limited is known for providing solutions that are a first of its kind in various industry sectors that it is present in. This one goes to the sustainability of fossil-based power generation and cost efficient power to fuel growth.