Renewable OME from biomass and electricity—Evaluating carbon footprint and energy performance

Energy Science & Engineering published by the Society of Chemical Industry and John Wiley & Sons Ltd. Renewable drop-in fuels provide a short- to medium-term solution to decreasing carbon dioxide emissions from the transport sector. Polyoxymethylene ethers (OME) are among interesting candidates with production pathways both from biomass (bio-OME) as well as electricity and CO2 (e-OME) proposed. In the present study, both bio- and e-OME production via methanol are assessed for energy performance and carbon footprint. Process integration methods are applied to evaluate synergies from colocating methanol production with further conversion to OME. Even a hybrid process, combing bio- and e-OME production is evaluated. The energy efficiency of bio-OME is considerably higher than for the e-OME pathway, and colocation synergies are more evident for bio-OME. Carbon footprint is evaluated according to EUs recast Renewable Energy Directive (RED\ua0II). If renewable electricity and natural gas are used for power and heat supply, respectively, results indicate that all pathways may be counted toward the renewable fuel targets under RED\ua0II. The largest emissions reduction is 92.8% for colocated hybrid-OME production. Carbon footprints of e- and hybrid-OME are highly sensitive to the carbon intensity of electricity, and the carbon intensity of the heat supply has a major impact on results for all pathways except colocated bio- and hybrid-OME

A computational tool for analysing the response of complex heat exchanger networks to disturbances

The heat exchanger networks (HEN) in industrial heat recovery systems often consist of large and complex subsystems. Calculating the response of such HENs to disturbances, such as varying inlet conditions or changing heat transfer capacities, may be challenging due to the presence of, e.g. stream splits and recycle loops. Extensive modelling and/or trial and error calculations may be necessary. This applies also for the analysis of different retrofit proposals. Retrofit opportunities in industrial heat recovery systems are often constrained by operability considerations, i.e. retrofit actions are supposed to have as little impact as possible on the production process to maintain the quality of the core product. Consequently, there is a clear demand for a tool to effectively screen design proposals at an early stage in the design process. In this work, a computational analysis tool is proposed to meet this demand. The proposed analysis tool allows fast evaluation of the network response when operating conditions change and/or operational settings are manipulated, and it is applicable for a wide range of HEN structures. The practical use of the analysis tool is demonstrated in a case study on the HENs of a large state-of-the-art Kraft pulp mill

Effects of process decarbonisation on future targets for excess heat delivery from an industrial process plant

The use of industrial excess heat for purposes such as district heating has the potential to contribute to societal targets for energy efficiency and greenhouse gas emissions reduction. However, to meet the ambitious national and international climate targets set for 2050, a breadth of different decarboni\uadsation pathways are required, not least in the industrial sector. These include a transition to bio-based and recycled feedstock and fuels, carbon capture and storage, and electrification. Such profound changes of industrial processes and energy systems are likely to affect the availability of excess heat from these plants, and a better understanding of how the excess heat po\uadtentials might change is needed in order to utilise excess heat in ways that can be resource-efficient also in the long-term. In this paper, we present a systematic approach which can be used to analyse how different decarbonisation options may af\uadfect the potential future availability of excess heat at a specific plant site. The approach is based on the use of consistent, ener\uadgy targeting methods based on pinch analysis tools, and there\uadfore relies on comprehensive data about process heating and cooling demands. To illustrate the approach, we demonstrate results from two industrial case studies in which different de\uadcarbonisation measures are assumed to be implemented. The case studies were selected from a case study portfolio, which includes relevant and site-specific process and energy data for a large share of Swedish industrial process sites. The results show that deep decarbonisation can have significant impact on the availability and temperature profile of industrial excess\ua0heat, illustrating the importance of accounting for future pro\uadcess development when estimating excess heat potentials

Fuelling the future: Assessing multifuel filling stations for hydrogen and other renewable fuels through life cycle analysis

Abstract Hydrogen could play an important role in reducing the climate impact of the transport sector. This study explores the possibility of using existing biomethane infrastructure to enable the accelerated roll‐out of hydrogen as a transport fuel in a Swedish context. The concept of multifuel filling stations for hydrogen and biomethane are examined based on four cases, where the hydrogen is produced either via electrolysis or biomethane reforming, at a smaller or larger scale, and through either centralised or decentralised production. The cases are compared using established life cycle assessment (LCA) methodology to establish their respective impact from a greenhouse gas (GHG) emission mitigation potential. The LCA results show generally good GHG performance for all production paths being studied with a range from −7 g CO2 eq./MJ hydrogen for hydrogen production based on biomethane via steam reformation (SMR) compared to +19 g CO2 eq. for production based on Swedish National Grid Mix via electrolyser. The SMR is the more efficient technology in mitigating GHG emissions, especially if system expansion is applied. In addition, sensitivity analyses also show that electrolyses production based on renewable wind power will decrease the impact significantly and vice versa that a European Average Electricity Grid Mix (EU – 28) would increase the impact significantly. The findings of this study underline the potential of the gradual introduction of hydrogen as a fuel for transport without the need for large investments in a dedicated fuel‐specific distribution system. The concept could contribute to overcoming the current chicken‐and‐egg catch of achieving both scalable and profitable supply of hydrogen for transport as well as the vehicles using it as fuel