<p>The global oil refining industry with its present shift inproduct distribution towards fuels such as gasoline and dieselwill most likely hold the fort for many years to come. However,times will change and survival will very much depend onprocessing flexibility and being at the frontiers of refiningtechnology, a technology where catalysts play leading roles.Today oil refiners are faced with the challenge to producefuels that meet increasingly tight environmentalspecifications, in particular with respect to maximum sulphurcontent. At the same time, the quality of crude oil is becomingworse with higher amounts of polyaromatics, heteroatoms(sulphur and nitrogen) and heavy metals. In order to staycompetitive, it is desirable to upgrade dense streams withinthe refinery to value-added products. For example, upgradingthe fluid catalytic cracking (FCC) by-product light cycle oil(LCO) into a high quality diesel blending component is a veryattractive route and might involve a two-step catalyticprocess. In the first step the LCO is hydrotreated andheteroatoms are removed and polyaromatics are saturated, in thesecond step naphthenic rings are selectively opened to improvethe cetane number of the final product.</p><p>The present research is devoted to the second catalytic stepof LCO upgrading and was carried out within the framework of aEuropean Union project entitled RESCATS.</p><p>From the patent literature it is evident that iridium-basedcatalysts seem to be good candidates for ring-opening purposes.A literature survey covering ring opening of naphthenicmolecules shows the need for extending investigations toheavier model substances, more representative of the dieselfraction than model compounds such as alkylated mono C5 and C6-naphthenic rings frequently employed in academic studies.</p><p>Ring-opening catalysts, mainly Pt-Ir based, were synthesisedat KTH by two different methods: the microemulsion and theincipient wetness methods. Characterization of the catalystswas performed using a number of techniques including TPR,TEM-EDX, AFM and XPS etc. Catalytic screening at atmosphericpressure using pure indan as model substance was utilized todetect ring-opening activity and the magnitude of selectivityto desired cetane-boosting products. The development of suchring-opening catalysts is the topic of Paper I.</p><p>When designing a catalytic system aimed at refiningpetroleum, it is crucial to monitor the evolution of thesulphur distribution throughout the different stages of theprocess so that catalyst properties and reaction parameters canbe optimised. The final section of this thesis and Paper II arethus devoted to high-resolution sulphur distribution analysisby means of a sulphur chemiluminescence detector (SCD).</p><p><b>Keywords:</b>ring opening, naphthenes, cetane numberimprovement, indan, light cycle oil (LCO), Pt-Ir catalyst,catalyst characterization, aromatic sulphur compounds, GC-SCD,distribution, analysis.</p>

The global oil refining industry with its present product distribution essentially shifted towards fuels such as gasoline and diesel will most likely hold the fort for considerable time. However, conditions are changing and refinery survival will very much depend on long-term planning, process and product flexibility and being at the frontiers of refining technology, a technology where catalysts play leading roles. Today oil refiners are faced with the challenge of producing fuels that meet increasingly tight environmental specifications, in particular with respect to maximum sulphur content. At the same time, the average quality of crude oil is becoming poorer with higher amounts of aromatics, heteroatoms (sulphur and nitrogen) and heavy metals. In order to stay competitive, it is of decisive importance for refiners to upgrade dense petroleum fractions of low quality to highly value-added products. A practicable route, for example, is upgrading the catalytic cracking by-product Light Cycle Oil (LCO) into a high-quality diesel-blending component in a two-step catalytic process. In the first step the LCO is hydrotreated over a Pt Pd based acidic catalyst bringing about heteroatom and aromatic reduction and isomerization of C6 to C5 naphthenic structures. In the second step these naphthenic structures are selectively opened over an Ir-based catalyst to improve the cetane value. The present thesis is mainly devoted to the second catalytic step of LCO upgrading and was partly conducted within the framework of the European Union project RESCATS. From the patent literature it is evident that iridium-based catalysts could be good candidates for ring-opening purposes. A literature survey covering ring opening of naphthenic structures made in the beginning of the project (in 2001), showed the need for extending investigations to heavier hydrocarbons, more representative of the diesel fraction than model compounds such as alkylated mono C5 and C6 naphthenic rings frequently employed in previous academic studies. Ring-opening catalysts, mainly Pt-Ir based, were synthesised at KTH by two different techniques: the microemulsion and the incipient wetness techniques. Paper I is a review of the microemulsion technique and its applications in heterogeneous catalysis. Characterization of catalysts was performed employing a multitude of techniques including quantitative TPR, TEM-EDX, XPS, CO FT-IR, NH3-DRIFTS and XRF etc. Catalytic screening at 325 oC and atmospheric pressure with hydrogen and pure indan as model substance was conducted to investigate ring-opening activity in terms of conversion and selectivity to desired cetane-boosting products. This development process is the topic of Papers II-IV. The possible industrial implementation of the best catalyst candidate is demonstrated in Paper V. When designing a catalytic system aimed at refining petroleum, it is crucial to monitor the evolution of the sulphur distribution throughout the different stages of the process so that catalyst properties and reaction parameters may be optimised. The final section of this thesis and Paper VI are devoted to high-resolution sulphur-distribution analysis by means of a sulphur chemiluminescence detector (SCD) following gas chromatographic separation. / QC 20101014

The global oil refining industry with its present shift inproduct distribution towards fuels such as gasoline and dieselwill most likely hold the fort for many years to come. However,times will change and survival will very much depend onprocessing flexibility and being at the frontiers of refiningtechnology, a technology where catalysts play leading roles.Today oil refiners are faced with the challenge to producefuels that meet increasingly tight environmentalspecifications, in particular with respect to maximum sulphurcontent. At the same time, the quality of crude oil is becomingworse with higher amounts of polyaromatics, heteroatoms(sulphur and nitrogen) and heavy metals. In order to staycompetitive, it is desirable to upgrade dense streams withinthe refinery to value-added products. For example, upgradingthe fluid catalytic cracking (FCC) by-product light cycle oil(LCO) into a high quality diesel blending component is a veryattractive route and might involve a two-step catalyticprocess. In the first step the LCO is hydrotreated andheteroatoms are removed and polyaromatics are saturated, in thesecond step naphthenic rings are selectively opened to improvethe cetane number of the final product. The present research is devoted to the second catalytic stepof LCO upgrading and was carried out within the framework of aEuropean Union project entitled RESCATS. From the patent literature it is evident that iridium-basedcatalysts seem to be good candidates for ring-opening purposes.A literature survey covering ring opening of naphthenicmolecules shows the need for extending investigations toheavier model substances, more representative of the dieselfraction than model compounds such as alkylated mono C5 and C6-naphthenic rings frequently employed in academic studies. Ring-opening catalysts, mainly Pt-Ir based, were synthesisedat KTH by two different methods: the microemulsion and theincipient wetness methods. Characterization of the catalystswas performed using a number of techniques including TPR,TEM-EDX, AFM and XPS etc. Catalytic screening at atmosphericpressure using pure indan as model substance was utilized todetect ring-opening activity and the magnitude of selectivityto desired cetane-boosting products. The development of suchring-opening catalysts is the topic of Paper I. When designing a catalytic system aimed at refiningpetroleum, it is crucial to monitor the evolution of thesulphur distribution throughout the different stages of theprocess so that catalyst properties and reaction parameters canbe optimised. The final section of this thesis and Paper II arethus devoted to high-resolution sulphur distribution analysisby means of a sulphur chemiluminescence detector (SCD). Keywords:ring opening, naphthenes, cetane numberimprovement, indan, light cycle oil (LCO), Pt-Ir catalyst,catalyst characterization, aromatic sulphur compounds, GC-SCD,distribution, analysis.