TO DEVELOP NEW METHODS FOR USE IN THE THERMAL CONVERSION OF HEAVY OILS AND RESIDUES TO AVOID OR LIMIT THE POLYCONDENSATION OF ASPHALTENES AND RESINS THAT RESULTS IN THE FORMATION OF PITCH AND COKE.
Research has been devoted to the performance improvement of the hydrovisbreaking (HVB) process and development of new thermal processes for conversion of heavy oils and conventional crude residues.
A study was made at the laboratory scale of the hydrogen donor or radical promotor compound behaviour in the HVB of residues.
Tests were then carried out on a micropilot unit and a industrial pilot plant.
Analysis and physiochemical characterization of the effluents then took place. The petroleum feedstocks used were the vacuum residuum (VR) SAFANIYA, a hydroprocessed VR, the atmospheric residuum (AR) ROSPONARE, VR KIRKOUK and VR NIGERIAN.
Work carried out on the thermal processing of residues in a batch reactor involved the following:
thermal treatment of VR SAFANIYA alone or with hydrogen sulphide;
HVB of VR SAFANIYA in the presence of hydrogen donor aromatic diluents or hydrogen transfer agents;
HVB of VR SAFANIYA in the presence of sulphur additives, acting alone or jointly with aromatic diluents;
HVB of VR SAFANIYA in the presence of industrial aromatic cuts;
influence of the residue nature on the HVB performances in the presence of diluents and additives.
Work on the physiochemical characterisation and analysis of thermal processing effluents involved the following:
liquid effluents characterization by chemical analysis and gel exclusion chromatography;
structural analysis of liquid effluents by nuclear magnetic resonance (NMR) of protons and carbon-13;
characterization of the thermal behaviour of liquid effluents and an attempt in appraising the stability of samples;
study of asphaltenes by X-ray diffraction.
The use of aromatic hydrogen donor solvent diluents remains an attractive idea for upgrading the hydrogen transfer efficiency in thepremesophasic liquid phase. Organometallic compounds (with molybdenum, iron, nickel, cobalt and vanadium as the metallic component) are initially soluble in the hydrocarbon phase and their decomposition in the HVB operating conditions produces a slurry of metallic particles which favour, at the local scale, the spill over of activated hydrogen.
MANY SOLUTIONS HAVE BEEN PROPOSED IN ORDER TO REDUCE THE ABOVE MENTIONED CONDENSATION, E.G. MAINTAINING AN APPROPRIATE H2S PARTIAL PRESSURE IN THE REACTION ATMOSPHERE, ADDING A REGENERABLE HYDROGEN-DONOR OR CRAKING ACTIVATING COMPOUNDS SUCH AS ALCOHOLS OR DISULPHIDES, ADDING A POWDERY SOLID CAPABLE OF ACTIVATING MOLECULAR HYDROGEN, USING DEMETALIZING CATALYSTS COUPLED WITH HYDROGEN DONORS. NEVERTHELESS, THE ROLE OF H2S AND OF MOLECULAR HYDROGEN IN THOSE PROCESSES IS STILL NOT PROPERLY UNDERSTOOD.
THE PROPOSED R&D WORKS AIMS AT THE CONTROL OF POLYCONDENSATION AND HYDROGENOLYSIS REACTIONS IN VISBREAKING UNDER HYDROGEN. THE FIRST PHASE OF THE PROJECT WILL CONSIST IN LABORATORY WORK, ON THE SCREENING OF POSSIBLE HYDROGEN-DONOR DILUENTS (HDD) AND RADICAL DONORS, AND IN ELUCIDATING THE MECHANISM OF THEIR INFLUENCE ON THE REACTIONS THAT TAKE PLACE IN THE CRACKING OF HEAVY PETROLEUM FRACTIONS. MUCH EFFORT WILL BE DEVOTED TO THE STUDY OF THE SYNERGISTIC ROLE OF H2S AND OTHER SULPHUR-CONTAINING SPECIES (THIOLS, DISULPHIDES) IN THE MODE OF ACTION OF SUCH COMPOUNDS IN THE PRESENCE OF ADDED H2. IN THE SECOND PHASE, THE BEST RESULTS PREVIOUSLY OBTAINED WIL BE TESTED ON A NUMBER OF TYPICAL RESIDUES IN CONTINUOUS RUNS ON MICRO-PILOT SCALE.
THE THIRD PHASE WILL BE CONCERNED WITH THE ANALYTICAL COMPARISON OF THE CRACKED PRODUCTS FROM PREVIOUS EXPERIMENTS. THE AIM IS TO COMPARE THE EVOLUTION OF HEAVY AND LIGHT COMPONENTS AFTER THE VARIOUS TREATMENTS. SPECIAL ANALYTICAL CHARACTERIZATION STUDIES WILL BE PERFORMED ON CHARGES, HEAVY RESIDUES AND ASPHALTENES. THE RESULTS WILL POSSIBLY BE USED TO IMPROVE THE VARIOUS CONVERSION PROCESSES WHICH ASVAHL IS TESTING IN SOLAIZE DEMONSTRATION PLANTS.
Funding SchemeCSC - Cost-sharing contracts