Throughout this thesis it is assumed that all available excess heat can be utilised. In all papers, except Paper IV, the excess heat is based on the current operation of the case refineries and is presented as process streams cooled with air and water as well as an additional cooling of flue gases.The existing process-to-process heat exchange network was assumed to be well constructed and accepted without further analysis. In Paper IV an energy-optimised refinery was assumed. In this paper it was assumed that all energy measures that are theoretically possible are executed before a BG-to- FT fuel production is installed. Furthermore, the FT syncrude process is also assumed to be maximally heat integrated and all excess heat is assumed to be available for usage.
In this thesis biomass is regarded as a limited resource, i.e. there is not enough biomass to substitute for all fossil-fuel based applications. In addition, the future available bioenergy potential is uncertain. Various estimates show a wide range of potentials. For example, within the Biomass Energy Europe project (Torén et al., 2011) the bioenergy potential for Europe was estimated to range from 1.3 to 7 PWh/y for 2030. Moreover, as discussed in for example Azar et al. (2003) and Faaij (2006), if the implementation of biomass is realised for co-firing in coal power plants, for the production of transportation fuel as well as for replacing fossil feedstocks in the industry, it would require more biomass resources than may be available. Therefore, it is not unrealistic to assume that woody biomass will be subject to competition from various existing and future biomass users. When
evaluating the GHG balance from biomass use, the GHG effect should always be
Chapter 2. Scope, Delimitations and Key assumptions
compared to an alternative use of the biomass, since the use of biomass for a new application results in less biomass being available for other purposes. This is further described in 6.3.
Considering capturing and storing CO2 emissions, the analysis in this thesis presupposes a functioning transportation system as well as safe storage sites for CO2. It is further assumed that the CCS option has gained public acceptance and that all legal obstacles and uncertainties have been resolved. The latter assumptions have also been employed in the analysis of BG-to-FT fuel and BG-to-H2 production. The cost estimates for transportation and storage are taken from (CCS Skagerrak - Kattegat, 2011) and presuppose transportation by pipeline. The cost has been calculated on full utilisation of the pipelines, i.e. that all the considered sources are equipped with CCS at the same time.
Currently, lack of space is a common problem at many refineries. Therefore, both the FT fuels production units and the post-combustion CO2 capture units are assumed to be located outside today’s primary process area. The estimated piping distance for utility systems, has been doubled to calculate for deviations from straight piping. For the CO2
capture case, the flue gases are assumed to be transported to a centralized capture plant, with the cost for flue gas channels included in the analysis.
Furthermore, when evaluating the potential for implementing CCS in BG-to-FT fuel production, Paper IV, the captured CO2 is assumed to originate from biomass feedstock.
Currently, CO2 emissions from biomass are not included in the EU ETS6. However, the same effects on global CO2 emissions are obtained if CO2 emissions are captured, regardless of origin. Therefore, it is assumed that in future policy systems, captured and stored CO2 originating from biomass will be granted the same economic compensation as CO2 originating from fossil fuels. The same view-point is discussed in more detail in for examples studies by Grönkvist et al. (2006), who argue for the importance of including credits also for biotic CCS in an international framework, i.e. not specifically within the EU ETS.
6 Emission Trading System
3 The European oil refining sector
Even if the main focus of this thesis is on a case study level it is relevant to know the characteristics of the whole industry, i.e. where refineries similar to the case refineries are located and the future demands for this industry. Therefore, this chapter gives an introduction to the European oil refining industry, describing the configurations and locations of the oil refineries. Overviews of current and future trends in the petroleum market, as well as a brief description of important adjacent infrastructures are also given.
The European oil refining industry (EU-27 + Norway) currently (2011) consists of 114 refineries, see Figure 1, with a combined capacity of approximately 770 Mt crude oil/y.
Refineries can be found in 22 of the 27 EU Member states and the oil refining stock in Europe consists of a variety of types of oil refineries, from base oil refineries, which are limited to the production of heavy fuel oil, to high conversion cracking refineries (IPPC, 2003). Oil refineries are often divided into different categories, depending on the configuration of a refinery. In this thesis the refineries are categorised based on the descriptions by the IPPC (2003) and Reinaud (2005), see Table 2. The case study refineries in the appended papers are categorised as Configuration 1 and Configuration 4.
Table 2. Refinery configurations, based on description in (IPPC, 2003; Reinaud, 2005) Configuration 1
including Base oil refineries
The simplest type of oil refinery. These refineries are equipped with a distillation unit, naphtha reformer, and some type of necessary treatment facility. The main product is often gasoline.
Base oil refineries do not have conversion units, which makes these refineries limited to the production of heavy fuel oil.
Configuration 2 Can convert fuel oil to a more valuable fuel by adding a vacuum distillation unit and a catalytic cracker to the units in Configuration 1.
Configuration 3 Configuration 3 adds a hydro cracker, which maximises the production of gasoline and middle distillates and allows the production of high-quality diesel.
Configuration 4 Has both hydro cracking and catalytic cracking units. Some refineries have an IGCC unit, which converts solids and heavy fuels to power and co-generation steam. Eleven refineries in the EU27 countries have a coker unit, which reduces heavy fuel oil to lighter fuels (i.e. diesel) and produces a low-value by-product, coke.
Figure 1. Map of all refineries in EU 27 + Norway. The green stars represent refineries with Configuration 4. Red triangles represent refineries with Configuration 3 and yellow circles represent refineries with Configuration 2. The blue rectangles present the base refineries and refineries with Configuration 1. This map includes Intellectual Property from European National Mapping and Cadastral Agencies and licensed on behalf of these by EuroGeographics.