Energy Efficiency and Integration in the Refining and Petrochemical Industries

Industrial sites and their associated energy systems are estimated to be responsible for 31% of worldwide energy consumption. Improving their energy efficiencies has the potential to reduce production costs of industrial sites and contribute towards the 2050 CO2 emission targets. Energy efficiency and integration studies in industrial sites aim to reduce the import of energy from external sources and maximise the use of internal energy sources, thereby reducing overall losses. As refineries and petrochemical sites are major energy consumers and are often located close to each other, they offer substantial potential for synergies and Energy Integration solutions. This thesis explores the energy requirements of these two industries and the elaboration of methodologies to identify energy efficiency solutions tailored to them. Data collection, reconciliation and preparation make up the first three chapters of this work. Typical refining and petrochemical clusters are described in detail revealing significant data issues. Data reconciliation methods are adapted to the specificities of these industries to close mass and energy balances and calculate unknowns including losses. To facilitate complex engineering studies, a methodology to identify scenarios from large data sets is proposed. Two complementary methodologies for the generation and evaluation of Energy Integration solutions are developed in the final two chapters. Firstly Total Site Analysis is adapted to the target industries, allowing for minimal data collection through a dual representation of utility and process requirements, process stream modelling and results generation. A mathematical formulation for optimised operations of steam networks is augmented to include load shedding when operating reserves are low. This is included into a simulation of boiler failures to establish the resiliency of steam network configurations. The data preparation methodologies, Total Site Analysis and steam network optimisation and simulation are applied to a typical refining and petrochemical cluster case study to establish energy efficiency solutions resulting in significant reduction in energy consumption.

The ORé Tool: Decision Support for Defining a Building Retrofit Strategy at Territorial Scale

Gaëtan Cherix, Fabien Luc Poumadère, Jakob Moritz Fabian Rager, Vincent Alexis Roch

The heating energy represents 35% of total energy consumption in Switzerland, and private households 60% of this consumption. The retrofit of residential buildings is a fundamental component of local energy policies. However, questions remain unresolved for many Swiss cities such as: How to know the potential in terms of retrofit of the territory? What are the priority buildings and why? What strategy to implement to achieve the objectives and what impacts on energy, costs and climate? Based on regional data, calculation with the Swiss norm SIA 380/1 per building enriched with data from our own database, the CREM has developed a semi-automatized tool to define a strategy for renovation of housing buildings on any Swiss territory. The method implemented into the tool prioritizes the buildings for retrofit based on potential energy, monetary and greenhouse gas (GHG) savings. The detailed methodology is presented here.

2016

MEU: An urban energy management tool for communities and multi-energy utilities

Massimiliano Capezzali, Gaëtan Cherix, François Maréchal, Jakob Moritz Fabian Rager, Damien Rebeix

In order to facilitate urban energy management and energy planning, the project MEU developed a web based tool as a decision support system for decision makers. Using a web based approach minimizes the effort on the client site as no software needs to be installed or be updated on the personal computer. Updates are published by the development team on the central server. During the first phase of the project, First, data are collected based on the buildings in the federal land registry offices' data. The data contains all the relevant elements in the energy conversion chain of a given city over the last couple of years available on an annual basis: meteorological data, a list of accessible resources, energy conversion technologies, energy distribution networks and buildings as consumers of different energy services. Second, all buildings and networks are geo-referenced to allow plotting maps. This already gives a comprehensive overview of the current energy state of a city. Third, measurements of (annual) energy consumptions are introduced allowing the performance monitoring. With the annual energy consumption of each energy conversion system, the current state of a city can be monitoring and compared to previous years. Fourth, this data is structured and completed for the use in the energy simulation software: CitySim for the dynamic building energy demand simulation and EnergyTechnology for the calculation of the energy conversion technologies. Especially the completion demands supplementary work as the data sets are often not very comprehensive. Therefore default values based on the current Swiss norms and previous publications are used to minimize the errors made in the simulations. As a set of default values is provided in the platform, it runs even if only a small data set is imported. When more information is available such as the energy consumption or the physical building data, the platform can easily be updated to increase the accuracy of the results. With this approach, urban energy flows from resource to useful energy can be tracked and inefficiencies can be spotted easily along the conversion processes. Furthermore, the creation of scenarios based on a given actual year allows for example the quick comparison of different energy conversion scenarios for different technological measures introduced in a city or the evaluation of refurbishment strategies on the energy demand. The maps allow to geo-localize priority areas and help representing the results.

2013

Methodology for the identification of promising integrated biorefineries

Ayse Dilan Celebi

Steady increase in global energy consumption, greenhouse gas emissions, and depletion of fossil energy resources, together with increased attention towards sustainable development has prompted researchers to discover economical and environmentally competitive non-petroleum alternatives and biomass is considered to be one of the most promising renewable sources of energy and carbon of this matter to address the aforementioned issues within a biorefinery platform. A biorefinery is an integrated processing facility that converts biomass into transportation fuels, value-added chemicals, heat, and electricity via biochemical and thermochemical conversion routes. Integrated biorefineries are capable of mimicking petroleum refineries via application of advanced process synthesis methods including modeling, simulation, integration and optimization techniques. This thesis presents a comprehensive synthesis methodology for the integration of bioprocessing technologies in biorefineries by addressing techno-economic and environmental sustainability analysis. The proposed systematic design approach combines advanced process modeling approaches, process integration techniques, and multi-objective optimization algorithms to assess the performance of the overall system with respect to economic, environmental, and energetic indicators. The design strategy is applied based on different case studies. Results indicate that multi-product processes can yield significant cost and environmental benefits. Additionally, the integration of biochemical and catalytic processes with thermochemical conversion pathways results in increased carbon efficiency and economic and environmental competitiveness. Synergies between biorefineries and energy system are assessed by integrating industrial plants with a cogeneration system producing biofuels and process heat. In doing so, system efficiency is increased by coupling the proposed cogeneration system with carbon capture and sequestration (CCS) and power-to-gas technologies to store the renewable intermittent electricity in the form of biofuels. The results exhibit that through system expansion, integrated biorefinery systems allow us to imitate fossil refineries with a large spectrum of bio-based products. This further increases the resource efficiency while offering a promising solution to mitigate CO2 emissions and hence reaching the longer-term decarbonization target set by the Paris Agreement.