International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 10 Issue: 04 | Apr 2023
p-ISSN: 2395-0072
www.irjet.net
POWER GENERATION BASED ON WASTE HEAT RECOVERY Mandadi V L N S Karthikeya Sharma1 PG student, Department of Mechanical Engineering1, Annamacharya Institute of Technology & Sciences, Kadapa, India1. ---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Production of electricity from low or moderate
and two adiabatic processes. But In a Carnot engine heat addition and rejection happen at uniform temperature.
temperatures is very difficult. To make it possible we need modern techniques. In every industry, power plants and process plants lot of low grade energy is wasted into the atmosphere. To recover this low grade energy, we propose Kalina cycle as a modern tool of thermodynamics. This Kalina cycle consists of multi component fluids as thermodynamic working fluid. Most of the heat is wasted near the boiler of the steam power plant, or at the flue gases coming out from chimney or stack. Using Kalina cycle we perform heat recovery task quite easily. Kalina cycle uses Ammonia and Water as working fluid. Using Aspen plus simulation tool the simulation work was performed and a reliable result was obtained. The Heat recovery from flue gases coming out from chimney of any industry may be studied using Aspen plus. Composition of Ammonia and Water mixture was varied from 0.5 to 0.9 mass fraction of Ammonia. Flow rate of hot gases is kept constant, assuming that there is constant burning of fuel in the boiler. Power generated in this process was tabulated and efficiency of the process is also calculated.
Fig.1 Carnot cycle
1.1 Ammonia-water power cycle principle The ammonia and water mixture is non-azeotropic. The characteristic for non-azeotropic mixtures is that the composition and temperature changes during boiling at all possible compositions of the mixture. When the mixture starts boiling, a separation of the components takes place. The vapour is richer in ammonia fraction than the liquid. The starting point for the boiling is called the bubble point and the end point is called the dew point. The bubble point temperature for a mixture with a mass fraction of ammonia of 0.5 at a pressure of 11 MPa is 204 °C. During the boiling the temperature of the mixture increases as the composition changes. When the temperature of the boiling mixture has reached 230°C, the mass fraction of ammonia in the liquid phase is 0.37, while in vapour phase it is 0.70.
Key Words: Kalina Cycle, Flue gas, Heat Recovery, Power
1. INTRODUCTION The energy demand in the world is expected to increase continuously. In order to minimize the negative environmental impact from utilizing energy resources, more efficient energy conversion processes are necessary. The electrical power demand is also expected to be very high in future. It is therefore a great interest to be taken to improve the efficiency of power generating processes and power plants. This can also be very good from for the national economic point of view. There are many possible ways in which these improvements can be achieved [4]. Kalina cycle was first developed by Alexandr I. Kalina [1] in the late 1970’s and early 1980’s. Based on this, several Kalina cycle have been proposed for different applications. Kalina cycle uses a working fluid comprised of at least two different components, typically Water and Ammonia. The ratio between those components varies in different section or parts of system to decrease thermodynamic irreversibility and thereby to increase the overall thermodynamic efficiency [1]. In thermodynamics, the Carnot cycle has been described as being the most efficient thermal cycle possible, wherein there are no heat losses, and consisting of four reversible processes, two isothermal
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1.2 Comparison between Kalina cycle, Rankine cycle and ORC The Kalina cycle is principally a ‘‘modified’’ Rankine cycle. These special designs, either applied individually or integrated together in a number of different combinations, comprise a family of unique Kalina cycle system. In theory, the Kalina cycle can help to convert approximately 45% of direct-fired system’s heat input to electricity and up to 52% for a combined-cycle plant. Moreover, Kalina cycle can give up to 32% more power in the industrial waste heat application compared to a conventional Rankine steam cycle. However, the Kalina cycle in small direct-fired biomass fuelled cogeneration plant do not show better performance
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