Thermodynamic and Economic Studies of a Combined Cycle for Waste Heat Recovery of Marine Diesel Engine

In the present study,the thermodynamic and economic performance of a combined thermodynamic cycle formed by an ORC and a Kalina cycle,which can simultaneously recover waste heat of exhaust gas and cooling water of marine engine,has been analyzed.Two typical marine engines are selected to be the waste heat source.Six economic indicators are used to analyze the economic performance of this combined thermodynamic cycle system with different marine engine load and under practical comprehensive operating condition of marine engine.The results of the present study show that the combined thermodynamic cycle system with R123 as organic working fluid has the best performance.The system with cis-butene has the worst economic performance.Under practical comprehensive operating conditions of ships,R123 has the shortest Payback Periods,which are 8.51 years and 8.14 years for 8 S70 ME-C10.5 engine and 5G95 ME-C10.5 engine,respectively.Correspondingly,payback Periods of Cyclopentane are 11.95 years and 11.90 years.The above values are much shorter than 25 years which are the lifetime of a marine ship.Under practical comprehensive operating conditions of ships,the combined cycle system can provide output power which is at least equivalent to 25%of engine power.Considering that R123 will be phased out in near future,cyclopentane may be its good successor.Cyclopentane can be used safely by correct handling and installing according to manufacturer's instructions.

A computational simulation study for techno-economic comparison of conventional and stripping gas methods for natural gas dehydration

In the present work,the conventional natural gas dehydration method(CDM)and stripping gas method(SGM)are technically and economically analyzed,utilizing Aspen HYSYS and Aspen Process Economic Analyzer(APEA),respectively.To optimize the CDM and SGM,the sensitivities of the water content of dry gas,reboiler duty and raw material loss are analyzed against solvent rate and stripping gas rate.The optimized processes are set to achieve a targeted value of water content in dry gas and analyzed at optimized point.The analysis shows that SGM gives 46%lower TEG feed rate,42%lower reboiler duty and 99.97%pure regenerated TEG.Moreover,economic analysis reveals that SGM has 38%lower annual operating cost compared to CDM.According to results,from both technical and economic point of view,SGM is more feasible for natural gas dehydration compared to CDM.

Study on Energy Issues Regarding Sustainable Economic Development of China

1 Overview on China's Energy Development Over the past twenty years China has made astonishing achievements in the energy domain and the total output of coal, electricity and petroleum ranked respectively the first,second and fifth place in the world.……

Economic overview of a two-agent process for underground coal gasification with Fischer-Tropsch- based poly-generation

Underground Coal Gasification(UCG)is a mining-gasification process that produces synthesis gas from in situ coal by injecting air(or oxygen and steam)and extracting the produced gas via boreholes.The resulting synthesis gas(‘syngas’)produced by UCG can be used directly as a fuel-gas or deep-cleaned to produce many other products like chemicals,liquid fuels,hydrogen and synthetic natural gas.UCG has significant environmental,safety and practical advantages over conventional coal mining and utilization,foremost being cost and emissions reductions.In South Africa,facilities of an industrial-scale Fischer-Tropsch(FT)have been operating for decades on coal-to-liquid and gas-to-liquid conversion.Oxygen-blown UCG produces syngas,which contains a mixture of carbon monoxide(CO)and hydrogen,and these molecules can be conditioned to serve as feed for synthetic-crude-oil(‘syncrude’)conversion technologies based on the FT process.African Carbon Energy(Pty)Ltd.(Africary)completed a study integrating its UCG technology with mini gas-to-liquids plant.Syngas from Africary’s Theunissen Underground Coal Gasification(TUCG)project will be used for power production and synthesis of liquid fuels in a unique poly-generation configuration.The TUCG process will consist of two parallel gasifiers,operated on different agents,making the component parts of UCG and coal-to-(any product)(CtX)tightly linked and interdependent,but reducing both cost and emissions.UCG-CtX offers a lower capital investment to conventional underground mining and surface gasification due to the removal of the surface gasifier and coal-mine operations.The gas clean-up systems will remove undesirable components from each gasifier and blend the cleaned syngas for H2:CO ratio control and provide implementation of carbon capture and sequestration.This study has minimized the complexity and optimized the process flow to provide own-use electricity and about 4000 barrels/day equivalent fuels at a capital cost estimate(2017)of about US$350 million and operating cost of around 28 US$/barrel.

The Study of Rationalization of the Economic Functions in Shanghai——the Study Group of the “Same topic”

From the PersPective of the systemsaPProaeh,the urban eeonomie functions re-fer to the role Played by the eeonomy of theeity in its surrounding areas.Beeause of different geograPhieal loeations,historiealeonditions,the various roles and funetionsof the eities in the national economy,theeeonomie funetions of a eity may be of