Distillation residues upgrading

A number of technologies are available to upgrade distillation residues [2]. Thermal processing is the traditional way to treat residues. Examples include visbreaking, flexicoking,... 

The results demonstrate that presulfiding has an overall positive effect on catalyst performance in processing residues. The improvements are specifically in areas of significant interest in residue upgrading namely, conversion to distillates and asphaltenes reduction. The... 

The liquid products were distilled to determine the yield and properties of the residual (343°C+) and light liquid (343°C ) products. Table VI shows that Runs 2 and 3 in Table IV resulted in 27 and 34 wt.% conversion of the 343°C+ fraction, while the sulfur in this fraction was reduced to 0.25 and 0.18 wt.%, respectively. The distillate and light liquid product (343°C ) are also upgraded in this process. The additional light distillates produced could presumably be recycled to the liquefaction reactor or utilized as low sulfur light distillate fuel. 

Bitumen is recovered using a caustic assisted hot water flotation process and diluted with naphtha to facilitate the removal of residual solids and water. Diluent naphtha is removed by distillation prior to feeding bitumen to the Upgrading facilities. 

Catalytic cracking is the process of upgrading gas oil or even residual oil (heavy oil) to produce gasoline, distillates, light olefines, etc. Commercialized processes include fluid catalytic cracking (FCC), residual oil catalytic cracking (RFCC), and catalytic pyrolysis, etc. 

The products obtained by refining and upgrading heavy crude oils are largely determined by market demand. The consumption of transport fuels is always such as to focus attention on the conversion of lighter [1] or heavier [2] feed stocks to appropriate distillation cuts. The processing of heavy residual oils into lighter oils is now widely practised, although the methods used may vary from refinery to refinery [3,4],... 

ARDS unit works as the springboard in the new scheme of Mina Abdulla Refinery operation Primarily a desulfurization unit, ARDS also reduces the metals, asphaltenes and nitrogen in the products, thereby, ensuring proper quality of feed for downstream conversion units. As an additional benefit, ARDS is also a mild hydrocracking process, partially upgrading high sulfur atmospheric residue to low boiling products like naphtha and distillate. 

Our main purpose for developing residual hydroconversion catalyst is the upgrading of petroleum residue, decomposition of asphaltenic components and hydrocracking of hydrocarbons to obtain useful middle distillates from petroleum residue. Through extensive studies on HDS catalysts, hydroconversion was determined to be entirely dependent on reaction temperature [2]. On the other hand, coking and metal deposition onto catalyst were reported to occur under such high temperatures as to decrease catalyst activity and shorten catalyst life [5,6,7,8]. 

From the beginning, FCC was employed to upgrade atmospheric (or long) residue. By distillation under vacuum, FCC feedstock (also called VGO) was separated from vacuum (or short) residue. Distillation techniques have been extended to increase the yield of FCC feedstock, and this development (revamps of vacuum units) is still taking place at various refineries. This deeper distillation does sufficiently restrict metals (Ni, V, etc.) and nonreactive and coke-producing components (CCR) in the distillate FCC feedstock. In some cases, deasphalting was and is employed to further increase the yield of acceptable FCC feedstock. 

The H-Oil process is a catalytic hydrogenation technique that uses a one-, two-, or three-stage ebullated-bed reactor in which considerable hydrocracking takes place during the reaction. The process is used to upgrade heavy sulfur-containing crude oils, residual stocks, and low-sulfur distillates, thereby reducing fuel oil yield. 

An existing lube hydrocracker can be operated at higher severity to make this special product, but the sharp reduction in yield may not be attractive for the base oil plant economics. However, an alternative source of hydrocracked base oil is available from some of the many existing fuel crackers. These hydrocrackers are important refinery conversion units and are used to make a range of fuel products from vacuum distillate feedstocks. Some plants do not fully convert the feed in one pass to low-boiling products and the limited amount of residue which remains, 5-10%, can be recycled within the plant, used as a fuel oil blending component or upgraded to make the special base oils. 

Based on the results of the experiments with different types of oil feedstock (heavy crude oil, residue of primary oil processing, wastes of oil extraction, lubricants, etc.), new radiation technologies were developed for deep processing and upgrading high-viscous crude oil, heavy residua of oil primary distillation, wastes of oil extraction, and bitumen. Figure 15.8 shows an example of RTC application to heavy fuel oil. 

Before the final upgrading by distillation, the crude phthalic anhydride is thermally pretreated at temperatures of 230 to 300 °C in the pre-decomposer. This causes the by-products (maleic acid, maleic anhydride, o-tolualdehyde, benzoic acid, phthalide, among others) to be partly decomposed, resinified or driven off. The heat-treated crude phthalic anhydride is fractionated by continuous distillation into fore-runnings, pure phthalic anhydride and a residue. 

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