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Thermal Power Plants and Pollution
Published in T.M. Aggarwal, Environmental Control in Thermal Power Plants, 2021
Biological and thermal impact. The effect on biological environment can be divided into two parts, viz. the effect on flora and the effect on fauna. Effect on flora is due to two main reasons, land acquisition and due to flue gas emissions. Land acquisition leads to loss of habitat of many species. The waste-water being at higher temperature (by 4–5°C) when discharged can harm the local aquatic biota. The primary effects of thermal pollution are direct thermal shocks, changes in dissolved oxygen, and the redistribution of organisms in the local community. Because water can absorb thermal energy with only small changes in temperature, most aquatic organisms have developed enzyme systems that operate in only narrow ranges of temperature. These stenothermic organisms can be killed by sudden temperature changes W. K. Pokale: Effects of Thermal Power Plant on … 214 that are beyond the tolerance limits of their metabolic systems. Periodic heat treatments used to keep the cooling system clear of fouling organisms that clog the intake pipes can cause fish mortality.
Carbon, Nitrogen, and Sulfur in Water Pollution
Published in Jerome Greyson, Carbon, Nitrogen, and Sulfur Pollutants and Their Determination in Air and Water, 2020
Heat generated by power and industrial plants may be discharged from them in the form of cooling waters. Increased water temperature resulting from thermal pollution is detrimental to ecological balance because it accelerates chemical and biological activity.
The Nuclear Steam Supply System and Reactor Heat Exchangers
Published in Robert E. Masterson, Nuclear Reactor Thermal Hydraulics, 2019
Up to this time, we have assumed that the waste heat discarded from the condenser is simply dumped into an outside reservoir such as a river or a lake. In some cases, it may also be dumped into the ocean. When this is not possible, the waste heat can be discarded using a cooling tower. Reactor cooling towers can be as much as 150 m (500 ft) high, and when cooling towers are used, most nuclear power plants use at least two of them to remove the waste heat. Cooling towers have undergone significant design changes over the years, and in well-designed cooling towers, as little as 1 m2of surface area is required for every 1,000 m2that a comparable cooling pond or a lake would use. Cooling towers can minimize the thermal pollution to lakes and rivers surrounding a power plant, and in addition, they can also allow most of the cooling water to be recycled.
Environmental and human health impacts of geothermal exploitation in China and mitigation strategies
Published in Critical Reviews in Environmental Science and Technology, 2023
Yuanan Hu, Hefa Cheng, Shu Tao
Besides the pollutants emitted, thermal pollution resulting from the heat released into the air and the discharge of geothermal tailwater into surface water and soil, particularly at the sites of power generation, also affects the wild fauna and flora (Rybach & Kohl, 2004). In particular, discharge of geothermal tailwater into natural water bodies can trigger a range of sublethal effects on aquatic organisms, similar to those brought by the thermal pollution of conventional power generation (Shiomoto & Olson, 1978). In addition, increase in temperature can reduce the dissolved oxygen and enhance the harmful effects of nutrients and toxins on aquatic organisms (Vallero, 2019). As a result, thermal pollution brought by geothermal exploitation can cause direct and indirect damages, and lead to significant biodiversity loss in aquatic ecosystems (Davidsdottir, 2012). The abundance of bacteria and archaea in the surface soils of Tengchong geothermal field was found to change markedly with temperature, with the microbial communities at the high-temperature sites being much simpler than those at the sites with low temperatures (Li et al., 2015). These findings indicate that significant changes in soil temperature brought by geothermal pollution could also cause loss in the biodiversity of soil microbial communities.
Multi-criteria optimisation of integrated power systems for low-environmental impact
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Kesiena Owebor, Ogheneruona E. Diemuodeke, Tobinson A. Briggs, Ogheneakpobo J. Eyenubo, Oreva J. Ogorure, Michael O. Ukoba
Sustainable power generation is the bedrock of a sustainable economy. As a lower-middle income country, Nigeria cannot provide sufficient electricity for its citizenry. The worst of it is that, most of the economic cities in the country are facing acute power shortage from the national grid. In this study, five power generation systems configurations are proposed with view of (i) enhanced power supply, (ii) thermal pollution minimization, (iii) carbon dioxide mitigation, and (v) proper guidance into the energy transition future. The proposed systems configurations became very important as most of the existing power generation plants in the country are simple cycle power plants, which do not harvest sufficient useful energy from the primary energy, and again, contribute to climate change. The proposed systems include SOFC-GTC, SOFC-GT-STC, SOFC-GT-ST-ORC, SOFC-GT-ST-OR-ARC, and SOFC-GT-ST-OR-AR-CCS. These systems were modeled, analyzed, and thereafter, subjected to multi-criteria optimization to ascertain the best configuration in the face of technical, economic and social considerations. The results of this analysis suggest that it is best to integrate a carbon capture technology into a thermally driven power generation system so as to mitigate against the implication of global warming. The optimal configuration presents, 207.5 MW, 42.93%, 42.49%, 93.5%, and 0.029 ton/MWh, as the net power, energy efficiency, exergy efficiency, amount of carbon captured, and CO2 emission factor, respectively. A major benefit of the optimal system in the pursuit of a low emission future is the low emission factor of 0.029 ton/MWh, as against other configurations at 0.332–0.401 ton/MWh.
Review of enhanced heat and mass transfer by additives
Published in Science and Technology for the Built Environment, 2022
Luning Wang, Han Sun, Zhongbao Liu
The energy consumed by industrial processes is mainly fuel and electricity, and the waste heat resources generated in this process are abundant. The use of waste heat resources for industrial production, heating, cooling, and other applications can reduce the consumption of primary energy and thermal pollution to the environment. Reasonable utilization of waste heat resources, especially low-grade heat sources, is essential. Absorption refrigeration systems use thermal energy as the driving heat source; they can also utilize low-grade energy, such as waste water and exhaust gas, as the driving heat source. Therefore, the power consumption of absorption refrigeration systems is low, and the energy-saving effect is evident.