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When modelling the environmental and economic aspects of meeting a given heat and power demand with a combination of combined heat and power (CHP) and grid power, it is common to use a coarse temporal precision such as 1-h demand blocks in heat and power demand data. This may be appropriate for larger applications where demand is reasonably smooth, but becomes questionable for applications where demand...
Oxy-gasification, or oxygen-blown gasification, enables a clean and efficient use of coal and opens a promising way to CO 2 capture. Moreover, oxy-co-gasification with biomass implies the use of a renewable resource and additional CO 2 reduction. Proper gasifier operation is a key issue in both techniques. A model of an entrained flow gasifier, validated with nearby 3000 actual steady-state...
Ever since the release of the Kyoto protocol the demand for CO 2 -free processes have been increasing. One of the most expanding sources of electric power in the industrialised world today is the gas-fired combined cycle, combining high efficiency and low investment cost. In this paper, the integration of a post-combustion CO 2 -separation unit into a combined cycle is studied from...
The integration of different energy systems, e.g., industrial and municipal, is potentially important for the efficient utilization of energy. It is important that the tools for analysing this type of integration can handle the energy systems on different levels, e.g., regional, site, plant and process levels. In this work, a framework for investigating the cost-efficient integration of large-scale...
Converting wood to grid quality methane allows to distribute a CO 2 free, renewable energy resource in a conventional energy distribution system and use it in transportation applications. Applying a multi-objective optimisation algorithm to a previously developed thermo-economic process model for the thermochemical production of synthetic natural gas from wood, the present paper assesses the...
The molecular characterisation of refinery feedstocks is a challenging task since, typically, a vast number of components are present in the mixture. Non-experimental approaches for characterisation of hydrocarbon streams fall into three categories: pseudo-component, compound class and average structural parameter methods. In this work, a new compound class approach is used to represent any hydrocarbon...
Strategic behaviour by gas producers is likely to affect future gas prices and investments in the European Union (EU). To analyse this issue, a computational game theoretic model is presented that is based on a recursive-dynamic formulation. This model addresses interactions among demand, supply, pipeline and liquefied natural gas (LNG) transport, storage and investments in the natural gas market...
This paper presents the analysis of the influence of fuel price variation on the optimal values of the design variables of the steam part of a combined cycle plant. The investigated system was a power plant with a triple-pressure heat recovery steam generator and extraction-condensation steam turbine. Fourteen design variables for the steam part were identified. The variables that were optimised were...
In this series of two articles, the concepts and approaches of environomic (thermodynamic, economic and environmental) performance ‘Typification’ of power generation technologies (Part I) and of combined heat and power (CHP) cogeneration technologies (Part II) in the context of CO 2 abatement are introduced. A methodology is then proposed for a flexible and fast project based power or CHP...
The extensive energy use in the European building sector creates opportunities for implementing energy conservation measures (ECMs) in residential buildings. If ECM are implemented in buildings that are connected to a district heating (DH) system, the operation of DH plants may be affected, which in turn may change both revenue and electricity production in cogeneration plants. In this study a local...
The paper deals with the effect of some selected quantities occurring in the legal and economical environment on the optimal values of some selected design quantities of a natural-gas-fired CHP plant. This trend of investigations results from the newly observed legal changes in the legislation concerning new forms of mechanisms supporting the combined production of electricity and heat. Special stress...
The reduction of CO 2 emissions linked with human activities (mainly energy services and transport), together with the increased use of renewable energies, remain high priorities on various political agendas. However, considering the increased consumption of energy services (especially electricity), and the stochastic nature of some of the most promising renewable energies (wind for instance),...
Heavier crude oil, tighter environmental regulations and increased heavy-end upgrading in the petroleum industry are leading to the increased demand for hydrogen in oil refineries. Hence, hydrotreating and hydrocracking processes now play increasingly important roles in modern refineries. Refinery hydrogen networks are becoming more and more complicated as well. Therefore, optimisation of overall...
The small-scale open and direct solar thermal Brayton cycle with recuperator has several advantages, including low cost, low operation and maintenance costs and it is highly recommended. The main disadvantages of this cycle are the pressure losses in the recuperator and receiver, turbomachine efficiencies and recuperator effectiveness, which limit the net power output of such a system. The irreversibilities...
This paper presents results from a prototype renewable energy network optimisation model, which is driven with output from a high resolution mesoscale weather model of the current climate. The network model estimates potential power output for various combinations of wind and solar farms across a large domain of several hundred kilometres and calculates the required back-up power capacity needed to...
This paper addresses the optimisation of short-term hourly scheduling (one week ahead) of (CHPs) cogeneration plants inside large industrial sites. The heat demand in these sites is very high and is crucial for industrial processes.This optimisation aims to find the CHP operation points that maximise the profits from the sale of heat and electricity. The electricity price must be forecasted because...
To face global competition, and also reduce environmental and climate impact, industry-wide changes are needed, especially regarding energy use, which is closely related to global warming. Energy efficiency is therefore an essential task for the future as it has a significant impact on both business profits and the environment. For the analysis of possible changes in industrial production processes,...
This paper presents a mixed-integer linear programming (MILP) super-structure model for the optimal design of distributed energy generation systems that satisfy the heating and power demand at the level of a small neighborhood. The objective is the optimal selection of the system components among several candidate technologies (micro combined heat and power units, photovoltaic arrays, boilers, central...
An optimisation model for the composition of mixed working fluids for (Organic Rankine Cycles) ORCs and Kalina cycles has been developed. The temperatures investigated were 100 °C–250 °C for the heat source and 30 °C for the heat sink. The optimisation method of the composition was carried out with Simulated Annealing technique with the objective function of maximising the thermal efficiency of the...
EFB (Empty fruit bunch) is among the palm oil biomass residues that have been identified as the most abundant bioenergy resources in Southeast Asia. EFB has a good potential to meet the targeted share of renewable energy in this region. This work presents robust LP (linear programming) model to allow for the synthesis of EFB allocation networks that exhibit operational flexibility under multiple biomass...
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