Integration of ThermoChemical Energy Storage in Concentrated Solar Power. Part 1: energy and economic analysis/optimization

Coupling of Concentrated Solar Power and Thermo-Chemical Energy Storage is a very interesting option because of the high efficiencies attainable with a renewable source and the large variation of solar radiation. Thermo-Chemical Energy Storage based on Calcium-Looping represents a promising opportunity thanks to high operating temperature, high energy density, null thermal losses and cheap calcium oxide precursor exploitable. The large variety of suitable power blocks and the importance of their integration in the discharging process makes it necessary to perform a coherent analysis of the selected alternatives, in order to compare them and establish the most convenient integration. Many aspects must be taken into account, such as system efficiency, investment costs and layout complexity. The purposes of the present work are: the development of a methodology to simulate the entire plant operations; the synthesis of heat recovery systems for both the charging and discharging processes; the execution of an economic analysis and the development of economic optimizations for the design/dimensioning of solar side and calciner side. Between the options investigated, power blocks based on supercritical CO2 are the most convenient both in terms of global efficiency (higher than 19%) and capital investment, keeping this advantage also for higher plant sizes. The methodology here developed and the results obtained are useful information for a deeper analysis of the most promising integration alternative, which is performed in the second part of this study

Economic analysis and optimization for bio-hydrogen production from oil palm waste via steam gasification

Biomass steam gasification with in-situ carbon dioxide capture using CaO exhibits good prospects for the production of hydrogen rich gas. In Malaysia, due to abundance of palm waste, it is a good candidate to be used as a feedstock for hydrogen production. The present work focuses on the mathematical modeling of detailed economic analysis and cost minimization of the flowsheet design for hydrogen production from palm waste using MATLAB. The influence of the operating parameters on the economics is performed. It is predicted that hydrogen cost decreasing by increasing both temperature and steam/biomass ratio. Meanwhile, the hydrogen cost increases when increasing sorbent/biomass ratio. Cost minimization solves to give optimum cost of 1.9105 USD/kg with hydrogen purity, hydrogen yield, hydrogen efficiency and thermodynamic efficiency are 79.9 mol%, 17.97 g/hr, 81.47% and 79.85% respectively. The results indicate that this system has the potential to offer low production cost for hydrogen production from palm waste

On Envelope Theorems in Economics: Inspired by a Revival of a Forgotten Lecture

This paper studies how envelope theorems have been used in Economics, their history and also who first introduced them. The existing literature is full of them and the reason is that all families of optimal value functions can produce them. The paper is driven by curiosity, but hopefully it will give the reader some new insights.Envelope theorems; names and history; value functions

Evaluation of synergetic effects of integrated recirculating aquaculture systems with water electrolysis units

Recirculating aquaculture systems (RAS) are developing rapidly as a pathway towards a more sustainable and efficient aquaculture industry. Such facilities allow for precise control of parameters involved in fish farming, such as oxygenation units for providing oxygen and replenish oxygen saturation levels in the recirculated water. In order to locally supply the oxygen demand to these facilities, water electrolysis technology may be a complementary solution of which oxygen and heat are secondary products, typically unutilized in conventional production units, in addition to the main product which is hydrogen. To study the synergetic effects of combining RAS facilities for Atlantic salmon and water electrolysis systems, three pre-defined case studies of varying sizes have been established with regards to the technical feasibility, impact on the production cost of hydrogen, as well as sensitivity analyses of relevant economical variables. Simulation of the alkaline water electrolysis process is also carried out through Aspen Plus software, and the varying oxygen demand during the growth of Atlantic salmon is modeled for each case study presented in this report. The three case studies show considerable economical benefits through scale-up of the combined facilities. A promising hydrogen production cost of 27.74 kr/kg H2 was achieved for the largest facility (case 3), producing more than 50 tonnes of O2 per day, where revenues from oxygen sales and district heating are included. A more detailed techno-economic analysis, optimization of the general concept, a study of including alternative energy sources such as wind and solar, as well as further work with the simulated process in Aspen Plus may be recommended for future studies of the established cases in this paper

ALGORITHM FOR SOLVING THE INVERSE PROBLEMS OF ECONOMIC ANALYSIS IN THE PRESENCE OF LIMITATIONS

The solution of inverse problems is considered taking into account the restrictions using inverse calculations. An algorithm is proposed for solving the inverse problem, taking into account restrictions while minimizing the sum of the absolute values of the changes in the arguments. The problem of determining the increments of the function arguments is presented as a linear programming problem. The algorithm includes solving the inverse problem with the help of inverse calculations while minimizing the sum of the absolute changes in the arguments, checking the correspondence of the obtained arguments to the given restrictions, adjusting the value of the argument if it goes beyond the limits of acceptable values, and changing the varied arguments to achieve the given value of the resulting indicator. The solution of two problems with the additive and mixed dependence between the arguments of the function is considered. It is shown that the solutions obtained in this case are consistent with the result of using an iterative procedure based on changing the resulting value to a small value until a given result is achieved, and the results are compared with solving problems using the MathCad mathematical package. The advantage of the algorithm is a smaller number of iterations compared to the known method, as well as the absence of the need to use coefficients of relative importance. The presented results can be used in management decision support system

Economic Benefits of Waste Pickling Solution Valorization

An integrated hybrid membrane process, composed of a diffusion dialysis (DD), a membrane distillation (MD) and a reactive precipitation unit (CSTR), is proposed as a promising solution for the valorization and onsite recycling of pickling waste streams. An economic analysis was performed aiming to demonstrate the feasibility of the developed process with a NPV of about EUR 40,000 and a DPBP of 4 years. The investment and operating costs, as well as the avoided costs and the benefits for the company operating the plant, were analyzed with an extensive cost tracking exercise and through face-to-face contact with manufacturers and sector leaders. A mathematical model was implemented using the gPROMS modelling platform. It is able to simulate steady state operations and run optimization analysis of the process performance. The impact of key operating and design parameters, such as the set-point bath concentration and the DD and MD membrane areas, respectively, was investigated and the optimal arrangement was identified. Finally, operating variables and design parameters were optimized simultaneously in a nonlinear framework as a tradeoff between profitability and environmental impact. We show how the integration of new technologies into the traditional pickling industry could provide a significant benefit for the issues of process sustainability, which are currently pressing

Economic Benefits of Waste Pickling Solution Valorization

An integrated hybrid membrane process, composed of a diffusion dialysis (DD), a membrane distillation (MD) and a reactive precipitation unit (CSTR), is proposed as a promising solution for the valorization and onsite recycling of pickling waste streams. An economic analysis was performed aiming to demonstrate the feasibility of the developed process with a NPV of about EUR 40,000 and a DPBP of 4 years. The investment and operating costs, as well as the avoided costs and the benefits for the company operating the plant, were analyzed with an extensive cost tracking exercise and through face-to-face contact with manufacturers and sector leaders. A mathematical model was implemented using the gPROMS modelling platform. It is able to simulate steady state operations and run optimization analysis of the process performance. The impact of key operating and design parameters, such as the set-point bath concentration and the DD and MD membrane areas, respectively, was investigated and the optimal arrangement was identified. Finally, operating variables and design parameters were optimized simultaneously in a nonlinear framework as a tradeoff between profitability and environmental impact. We show how the integration of new technologies into the traditional pickling industry could provide a significant benefit for the issues of process sustainability, which are currently pressing

ALGORITHM FOR SOLVING THE INVERSE PROBLEMS OF ECONOMIC ANALYSIS IN THE PRESENCE OF LIMITATIONS

The solution of inverse problems is considered taking into account the restrictions using inverse calculations. An algorithm is proposed for solving the inverse problem, taking into account restrictions while minimizing the sum of the absolute values of the changes in the arguments. The problem of determining the increments of the function arguments is presented as a linear programming problem. The algorithm includes solving the inverse problem with the help of inverse calculations while minimizing the sum of the absolute changes in the arguments, checking the correspondence of the obtained arguments to the given restrictions, adjusting the value of the argument if it goes beyond the limits of acceptable values, and changing the varied arguments to achieve the given value of the resulting indicator. The solution of two problems with the additive and mixed dependence between the arguments of the function is considered. It is shown that the solutions obtained in this case are consistent with the result of using an iterative procedure based on changing the resulting value to a small value until a given result is achieved, and the results are compared with solving problems using the MathCad mathematical package. The advantage of the algorithm is a smaller number of iterations compared to the known method, as well as the absence of the need to use coefficients of relative importance. The presented results can be used in management decision support system