Unconventional crude oil upgrading hydrocracking process technology

Thread Content

(1) LC-Fining process. The LC-Fining process is a fluidized bed residue hydrocracking process developed by Chevron Rums Global. The characteristics of this process are reflected in the fluidized bed reactor. The feedstock enters the reactor from the bottom and flows upward to the outlet of the reactor. In the reactor, with the participation of hydrogen and a catalyst, the raw materials are converted into various distillate oils. Through numerous technical improvements, such as reactor cascading, removal of \"precursors to coke,\" and low-pressure purification of hydrogen, this process is now capable of processing high-sulfur residue oil, natural asphalt, oil sands, and coal tar. Currently, there are 5 industrial units that use this process to process oil sand asphalt vacuum residue, with a total processing capacity of 9.75 million tons per year. These units belong to Canadian Synthetic Crude Oil Company (1 unit), Shell Canada (3 units), and Northwest Corporation of Canada (1 unit). Integration with downstream hydrogenation or hydrocracking units to reduce capital and operating costs is an important technological advancement of the LC-Fining process, which has now been put into industrial use. Shell Canada’s Scotord bitumen upgrading plant came online in 2003, equipped with two LC-Fining units, each with a processing capacity of 40,000 barrels per day, to process ultra-heavy vacuum residue derived from Athabasca bitumen. (2) H-Oi process. The H-Oil process was the first hydrocracking technology for residue in a fluidized bed; it is relatively complex, and the initial version of this technology was not yet mature. An explosion occurred at the Humble refinery in 1970, which hindered the development of this process. By the 1980s, only 3 industrial H-Oil units had been built. After years of technical improvements, 4 new industrial units were built in the 1990s. The H-Oi fluidized-bed hydrocracking unit consists of two reactors connected in parallel, sharing one product separation system. The oil produced by hydrocracking is subjected to separation and cooling before being fed into atmospheric and vacuum distillation columns to yield naphtha, jet fuel, and gas oil, which are then further hydrogenated. The unconverted vacuum residue from hydrocracking is used as feedstock for the delayed coking unit. (3) EST process. The EST process is Eni’s residue slurry bed hydrocracking technology, representing a significant technological innovation in residue conversion and the upgrading of unconventional crude oils. The EST process utilizes nanoscale hydrogenation catalysts and an innovative process flow to completely convert crude oil into useful products, or to modify it into synthetic crude oil with a lower specific gravity (an increase in API gravity), without producing any residual by-products such as petroleum coke or heavy fuel oil. The core of the EST process is the suspended-bed reactor. Heavier crude oil is converted into lighter products in the presence of nanoscale aluminum-based catalysts. The conversion of crude oil begins with a thermal reaction, during which carbon-carbon bonds break to produce free radicals. Free radicals are suddenly quenched through H-adsorption reactions, preventing them from recombining to further form coke. The H-absorption reaction is promoted by the presence of highly active aluminum-based catalysts such as aluminum sulfide. Aluminum sulfide is formed by the in-situ decomposition of an oil-soluble precursor. In fact, this reaction produced nanoscale dispersed molybdenum sulfide (molybdenite) catalysts with high carrier-free hydrogenation activity. The use of carrier-free slurry catalysts is particularly useful for feedstocks containing large amounts of impurities such as metals and asphaltenes. Unlike conventional support catalysts used in fixed-bed and fluidized-bed reactors, dispersed molybdenite does not suffer from clogging problems caused by the deposition of metal and coke on the porous support. The oil that has been modified and flows out of the reactor enters the separation system, where gas, naphtha, middle distillate oil, and vacuum gas oil are recovered; the unconverted feed oil and the dispersed catalyst are recycled back to the reactor. Mixing the recycled and partially converted residue oil with aromatic oils such as the fresh feedstock oil can restore the stability of the recycled oil, thereby allowing it to be converted again and ultimately achieving near-complete conversion. After multiple cycles, the system reaches a stable state; as a result, almost all of the crude oil is converted into useful oil products. To remove the metals (nickel and vanadium) that enter the crude oil, it is necessary to discharge a small amount of tail oil. Therefore, EST can process heavy residue oil, and since it does not produce by-products such as coke and heavy fuel oil, it ensures a high conversion rate of distillate oil. One of the main advantages of the EST process is its good flexibility regarding raw materials. Over the past few years, various feedstocks have been processed (residues from conventional crude oil, extra-heavy crude oil, and asphalt), and the reliability of converting all residues into light, medium, and heavy distillates with very little tail oil being produced has been verified across different processes. Furthermore, all the options ensure excellent demetallization, decarburization, and desulfurization performance, as well as adequate denitration performance. Another feature is its ability to produce high-quality vacuum gas oil with low sulfur and low aromatic content. When there is market demand, this reduced-pressure gas oil can be further converted into diesel or gasoline through hydrocracking or catalytic cracking, ensuring product flexibility. After extensive research and development work in laboratories and pilot plants, the upgrading performance of the EST process has been demonstrated since 2005 at the 1,200 barrels per day industrial demonstration plant at the Tatanto refinery. Eni has decided to build the first industrial production unit at its Sannazzaro refinery, with a processing capacity of 20,000 barrels per day, and plans to put it into operation in the second quarter of 2012. (4) (HC)3 technology. (HC) 3 technology is a heavy oil catalytic hydrocracking process developed by Headwaters Company. This process can convert low-quality feedstocks such as heavy oil, residue, and oil sands asphalt into high-quality synthetic crude oil. This technology offers advantages such as stable product quality, high flexibility in raw materials, high selectivity, adjustable conversion rates (up to 95%), a high processing capacity for the reactor, and good safety in plant operation. The catalyst for (HC)3 technology is an organometallic liquid that can be easily dissolved in low-temperature liquid residue (thus it can be added upstream of the feed heater in the hydrocracking unit). By the time the catalyst reaches the reactor, it is already uniformly dispersed in the heavy oil, and without being subject to the geometric constraints associated with solid-supported catalysts, the catalytic reforming reaction can proceed. The product leaving the (HC) 3 reactor consists of the converted material and stable fuel oil (residue) products; this converted material is highly suitable for fixed-bed hydrotreatment of distillates, with much less coke precursor than in the original feedstock. (The HC) 3 process utilizes a continuous backmixed reactor, with operating temperatures and pressures similar to those of other hydrocracking technologies. The construction cost and operating expenses of this reactor are also lower than those of conventional fluidized bed systems, yet its conversion rate is much higher, with very little scaling in the downstream equipment. Because the (HC) 3 process can be easily combined with existing fluidized-bed and fixed-bed reactors, refineries can produce more light distillates from the same volume of heavy oil, or produce the same products using feedstock of lower cost. Calculated on the same basis as fluidized bed and fixed bed technologies, the cost of (HC) 3 catalysts (the cost of catalyst used per barrel of oil processed) can be comparable to that of solid catalysts. However, combining the benefits of (HC)3 with lower investment costs can reduce the cost per catalyst. Northwest Upgrading Company plans to build a heavy oil upgrading facility in Sturgeon, Alberta, Canada, with some of the facility’s design incorporating (HC)3 technology. At the beginning of 2005, Headwater Company took on the reactor engineering design for its heavy oil hydrocracking project. (5) GHU process. Genoi’s Hydrogenation Conversion Upgrading (GHU) technology is a newly developed catalytic hydrocracking process that improves the economics of upgrading heavy oils, asphalts, and refinery residues. This innovative technology overcomes the inefficiencies in heat and mass transfer associated with traditional fixed-bed reactors. By utilizing specialized mixing facilities between hydrocarbons and hydrogen, the GHU process can achieve high conversion rates at lower temperatures and pressures. GHU technology is based on catalytic hydrocracking; the hydrocracking reaction converts large molecules and other heteroatom-containing molecules into cyclic paraffinic petroleum fractions, while nitrogen, sulfur, and heavy metals can be reduced or removed. A high hydrogen partial pressure reduces the polymerization and condensation of aromatic groups, and by hydrogenation and controlling the molecular weight of hydrocarbons, the liquid volume yield can reach 103%–106%. (6) HDH Plus technology. HDH Plus technology is one of the most advanced technologies in the world for upgrading unconventional crude oil, and it is owned by Venezuela’s **Petroleum Company. This technology is a combination of hydrocracking and hydrorefining; it enables high conversion rates of 90%-95% as well as high liquid yields of 115% for heavy crude oils and refinery residues. The characteristic of this technology is that it involves the hydrogenation of slurry-form crude oil under conditions of a temperature of 250–500°C and a pressure of 5–30 MPa; the additives used are two types of particles: fine particles with a particle size of less than 90 micrometers and coarse particles with a particle size of 100–1000 micrometers. Thereafter, Intevep made technical improvements to separate, regenerate, and reuse the catalysts used in hydrothermal cracking (slurry bed); these catalysts are prepared by supporting active metals from groups VB, VIB, VIIB, VIIIB, IA, or IIA. (7) VRSH process. Vacuum residue slurry bed hydrocracking (VRSH) is a new process for upgrading heavy oil developed by Chevron. This process can convert heavy oil with a specific gravity of less than 10 API into a mixture mainly composed of gasoline, jet fuel, and diesel, with a conversion rate of up to 100% for the feedstock oil. Using this process, heavy oil or vacuum residue is combined with a specialized catalyst to form a slurry, which is then mixed with oxygen and circulated through several reactors at temperatures of 413–454°C and pressures of 14–21 MPa. A small amount of catalyst is continuously separated via a side stream, reactivated, and then returned for reuse. The cost of this process is expected to be comparable to that of the LC-fining fluidized-bed hydrocracking process for processing heavy oil or residue. This process has passed pilot testing, and semi-industrial plant trials are currently underway.