On the Allocation of Residues Cost using Conventional and Comprehensive Thermoeconomic Diagrams

Abstract

In a productive process, the achievement of products occurs simultaneously with residues generation. Environmental impact of residues is an important issue in energy systems analysis due to environmental regulations and sustainability assessment. Many waste treatment methodologies have been proposed and applied in thermoeconomics. However, this is a complex problem and the solution depends on the residue nature and its formation process. Most conventional methodologies are based on productive diagrams, using productive flows only, and allocate the residues cost among the productive equipment. This work surveys the main conventional methodologies for treatment of waste and presents an improved/updated methodology based on a comprehensive diagram, in which both physical and productive flows are represented and their flows cost are assessed and the subsystems are connected using the same physical flows presented in the flowsheet of the plant. Both the CGAM system and a combined cycle are analyzed. Comparisons are made with literature results, considering the same case studies. The presented methodology obtains consistent results from the point of view of the cost allocation in thermoeconomics. The novelty of this updated approach concerns how the residue cost is allocated in the comprehensive diagram: it is reinternalized in the internal loop of physical flows, instead of in the productive unit. It represents advantages since the equipment product/fuel ratio index is not affected, which is beneficial for thermoeconomic diagnosis application.

Thermoeconomic Modeling as a Tool for Internalizing Carbon Credits into Thermal System Analysis

“…In the H&S Model, the productive flows represent variations of the enthalpic, entropic and chemical components of the exergy between i and j according to Eqs. ( 8) - (10), respectively.…”

“…In these circumstances, thermoeconomics allows rational allocation (through physical criteria) of monetary, exergetic, and environmental costs for the final products. Therefore, it is possible to compare exergetic/monetary [10][11][12][13][14] and/or environmental [15][16][17][18] costs of each product with the production cost of each one in separate systems. Thermoeconomic methodologies have already been used to include environmental aspects, such as specific CO2 emissions.…”

Thermoeconomic Modeling as a Tool for Internalizing Carbon Credits into Multiproduct System Analysis

“…In such scenarios, thermoeconomics enables a rational allocation (based on physical criteria) of monetary, exergetic, and environmental costs for these final products. Consequently, a comparison becomes feasible between the exergetic/monetary/environmental costs of each product and the production cost of each individual product in separate systems, as shown in papers assessing the exergetic unit cost (in a regenerative gas turbine cogeneration system [13]; in a cogeneration system with gas turbine, intercooler, and supplementary firing [14]; and in a combined cycle [15]), monetary unit cost (in a gas turbine cogeneration system [16] and in a power generation system of a steel mill plant [17]), and emissions pollutant allocation (in gas and steam cogeneration systems [18], in a gas cogeneration system with supplementary firing [19], in a combined cycle [20], and in a dual product heat pump [21]). Despite the practical relevance of this aspect, in the literature review, no studies were found that dealt with the incorporation and internalization of the monetary unit cost linked to the carbon market in the thermoeconomic evaluations of multi-product plants.…”