H2 processes with CO2 mitigation: Thermo-economic modeling and process integration

Abstract

Within the challenge of greenhouse gas reduction, hydrogen is regarded as a promising decarbonized energy vector. The hydrogen production by natural gas reforming and lignocellulosic biomass gasification are systematically analyzed by developing thermo-economic models. Taking into account thermodynamic, economic and environmental factors, process options with CO 2 mitigation are compared and optimized by combining flowsheeting with process integration, economic analysis and life cycle assessment in a multi-objective optimization framework. The systems performance is improved by introducing process integration maximizing the heat recovery and valorizing the waste heat. Energy efficiencies up to 80% and production costs of 12.5-42$/GJ H2 are computed for natural gas H 2 processes compared to 60% and 29-61$/GJ H2 for biomass processes. Compared to processes without CO 2 mitigation, the CO 2 avoidance costs are in the range of 14-306$/t CO2,avoided . The study shows that the thermo-chemical H 2 production has to be analyzed as a polygeneration unit producing hydrogen, captured CO 2 , heat and electricity.

Decision support for ranking Pareto optimal process designs under uncertain market conditions

“…2) Pre-combustion CO 2 capture by physical absorption with Selexol in a natural gas fueled power plant (725 MW th,N G ) based on autothermal reforming. This option, referred to hereafter as NG pre-,has been described and analysed previously in [33] and [34] for and 0.19% N, and a humidity of 50%wt. This option, labeled hereafter as BM pre-, has been described and analysed previously in [35].…”

Thermo-environomic optimisation strategy for fuel decarbonisation process design and analysis

“…The captured CO 2 is compressed to 110 bar for subsequent transport and storage. The models and some specific results have been previously published in [34,35] for H 2 production and in [36] for power plants applications. It is focused here essentially on the competitiveness assessment of the electricity production processes with CO 2 capture illustrated in Figure 3.…”

Oil and gas platforms with steam bottoming cycles: System integration and thermoenvironomic evaluation

“…This work follows a design and optimisation methodology that has been applied for the conception of, among others, hydrogen processes [26] and biomass conversion processes [27]. The aim is to define the system configurations that, for example, simultaneously minimise the economic costs or environmental impacts, while maximising the internal heat recovery and the thermodynamic performance [25].…”

“…It is therefore a MINLP (Mixed Integer Non-Linear Programming) problem, decomposed in this work into two sub-problems, namely a master and a slave optimisation problem (Figure 4). Figure 4: Illustration of the applied methodology and computational framework, adapted from [26,28] The first step consists of developing a physical model of the system of interest: it builds on a superstructure including all the different technological options and uses process simulation software to calculate the energy and material flows, for a predefined set of operating conditions. The process simulations were carried out with Aspen Plus R version 7.2 [29], based on (i) the Peng-Robinson (PR) equation of state (EOS) [30] and (ii) the Schwartzentruber-Renon EOS [31,32].…”