A New Vacuum System for Steam Plant Condenser

In the current work, a simple and low energy consuming system is proposed for holding on the vacuum in the steam power plant system. The vacuum is created at the tip of an inverted U-pipe through which water flows by siphon effect due to the height difference in water surfaces of two tanks. This height difference and the elevation of the inverted U-pipe tip define the value of the vacuum to be grown. The U-pipe tip is connected to the discharge pipe of a compressor which draws a mixture of air, and water vapor from the steam condenser and raises their pressure a little higher than that of the inverted U-pipe tip. The mixture flows with the water down the inverted U-pipe till they depart the U-tube. A thermodynamic and fluid flow analysis is developed for predicting the performance of the proposed system. The results of this analysis show that the right selection of the mass flowrate ratio of water flowing in the inverted U-pipe to air and water vapor mixture sucked by the compressor from the steam plant condenser, in the range of 25,000, the height of the inverted U-pipe summit from the water level of the higher water tank greater than 9.2 m and the height difference of the water levels in the two water tanks small enough, in the range of 0.1 m saves the power of vacuum system by 80% less than that consumed when using compressor alone for venting the steam plant condenser.

Single Solution That Reduces Power Plants Heat Rates, Emissions, and Operating Costs

This article presents background and the test results for a NOx control solution applicable to pulverized coal-fired power plants (E-NOx) that resolve the operating challenges related to the use of low/ultra-low-NOx burners (LNB) for in-furnace control and SCR or SNCR for post-combustion nitrogen oxides reduction. The major results of CFD modeling and test data are presented, which confirm E-NOx capabilities to reduce NOx and consequently the consumption of ammonia/urea for units using post-combustion NOx control. Basic steam plant performance analysis per ASME codes in combination with test data suggested an appreciable reduction in the plant heat rate. The results of economic studies of E-NOx applications for power plants with different means of NOx control are presented in this article, demonstrating a simple payback period to be within 8–16 months. This is the first environmental technology that pays for itself thanks to a decrease in both fuel and NOx reducing reactants consumption, thus lowering operating and maintenance costs in comparison with best available current and retrofit technologies.

Simulation Techniques for Design and Control of a Waste Heat Recovery System in Marine Natural Gas Propulsion Applications

Waste Heat Recovery (WHR) marine systems represent a valid solution for the ship energy efficiency improvement, especially in Liquefied Natural Gas (LNG) propulsion applications. Compared to traditional diesel fuel oil, a better thermal power can be recovered from the exhaust gas produced by a LNG-fueled engine. Therefore, steam surplus production may be used to feed a turbogenerator in order to increase the ship electric energy availability without additional fuel consumption. However, a correct design procedure of the WHR steam plant is fundamental for proper feasibility analysis, and from this point of view, numerical simulation techniques can be a very powerful tool. In this work, the WHR steam plant modeling is presented paying attention to the simulation approach developed for the steam turbine and its governor dynamics. Starting from a nonlinear system representing the whole dynamic behavior, the turbogenerator model is linearized to carry out a proper synthesis analysis of the controller, in order to comply with specific performance requirements of the power grid. For the considered case study, simulation results confirm the validity of the developed approach, aimed to test the correct design of the whole system in proper working dynamic conditions.

A New Vacuum System for Steam Plant Condenser

In the current work, a simple and low energy consuming system is proposed for holding on the vacuum in the steam power plant system. In this system, vacuum is created at the tip of an inverted U-pipe through which water flows by siphon effect. The stream of water through this pipe is brought about from a reservoir to another one whose water surfaces are at certain height difference. This height difference along with the height of the inverted U-pipe tip defines the value of the vacuum that can be produced. At this tip, the U-pipe is linked to the discharge pipe of a compressor which draws a mixture of air, non-condensable gases and some water vapor from the steam condenser and raises their pressure a little higher than that of the inverted U-pipe tip so that the resistance of connecting pipe is overcome and the pressure at exit of this pipe is equal to that at the inverted U-pipe tip. The mixture flows along with the water down the inverted U-pipe till it leaves the pipe with the water. A thermodynamic and fluid flow analysis is developed for predicting the performance of the proposed system. The results of this analysis show that the right selection of the mass flow rates ratio of water flowing in the inverted U-pipe and air and water vapor mixture sucked by the compressor from the steam plant condenser, in the range of 25000, the height of the inverted U-pipe summit from the water level of the higher water tank greater than 9.2 m and the height difference of the water levels in the two water tanks small enough, in the range of 0.1m saves the power of vacuum system by 80% less than that consumed when using compressor alone for venting the steam plant condenser.