Hydrotreating plants

FIGURE 6.10 Hydrotreating plant. Courtesy, Amoco Oil Company. 

Aluminas are used in various catalytic applications, a-, y-, and -aluminas are all used as support materials, the first one in applications where low surface areas are desired, as in partial oxidation reactions. The latter two, and especially y-alumina, in applications where high surface areas and high thermal and mechanical stability are required. One of the most prominent applications of y-alumina as support is the catalytic converter for pollution control, where an alumina washcoat covers a monolithic support. The washcoat is impregnated with the catalytically active noble metals. Another major application area of high-surface aluminas as support is in the petrochemical industry in hydrotreating plants. Alumina-supported catalysts with Co, Ni, and/or Mo are used for this purpose. Also, all noble metals are available as supported catalysts based on aluminas. Such catalysts are used for hydrogenation reactions or sometimes oxidation reactions. If high... 

A severe hydrotreating plant will have a flow scheme similar to the hydrofinishing unit shown in Fig. 1.11. Hydrocracking is a highly exothermic reaction, so cold hydrogen must be injected at several points in the catalyst bed to moderate the temperature rise. Operating conditions are severe, with pressures of 100-180 bar and reaction temperatures of 350 20°C. 

A catalytic de-waxing plant resembles other hydrotreating plants and operating condition need not be particularly severe. Operating costs can be significantly less than solvent de-waxing, especially for low-pour-point oils where refrigeration costs become prohibitive [7, 8]. 

With the first commercial residue hydrotreating plant being built in Japan in the late 70s, several units for direct residue HDS have been planned and constructed (Kuwait, for example). 

Fuel Standard (2008) requires 5.0 x 10 gallons of biodiesel (or biomass-derived diesel, e.g., hydrotreated plant oils) in the domestic diesel pool in 2009 and 1 x 10 gallons by 2012 (Tullo, 2008). 

Determining metals content in hydroprocessing catalysts after a certain period of operation is very important to estimate metal deposition rate and catalyst life, and hence identify, for instance, which catalyst is better to process certain feed than others. These parameters are of great interest not only to catalyst manufacturers but also to refiners, process designers, and catalysis researchers, since the whole economics of a hydrotreating plant is mostly determined by catalyst life. 

Od condensed from the released volatdes from the second stage is filtered and catalyticady hydrotreated at high pressure to produce a synthetic cmde od. Medium heat-content gas produced after the removal of H2S and CO2 is suitable as clean fuel. The pyrolysis gas produced, however, is insufficient to provide the fuel requirement for the total plant. Residual char, 50—60% of the feed coal, has a heating value and sulfur content about the same as feed coal, and its utilisation may thus largely dictate process utdity. 

Older rerefining units used 2-5 kg/L of activated clay at 40—70°C and higher temperatures in place of TEE to clean the oil (80). More elaborate chemical and hydrotreating of used engine oils without a distillation step has been developed by Phillips Petroleum for processing 40,000 /yr (10 X 10 gal/yr). Establishment of a reflable feedstock supply is a critical consideration for larger rerefining plants. 

Consider the oil-recycling plant shown in Fig. 3.16. In this plant, two types of waste oil are handled gas oil and lube oil. The two streams are first deashed and demetallized. Next, atmospheric distillation is used to obtain light gases, gas oil, and a heavy product. The heavy product is distilled under vacuum to yield lube oil. Both the gas oil and the lube oil should be further processed to attain desired properties. The gas oil is steam stripped to remove light and sulfur impurities, then hydrotreated. The lube oil is dewaxed/deasphalted using solvent extraction followed by steam stripping. 

Some invaluable isolated actions were taken from time to time in the last twenty to twenty five years that prevented air quality from declining at an even faster rate. For example, energy demand was met (electricity and refined oil products) by expanding capacity of plants located outside of the MCMA a metro was built the vehicular traffic system was reordered and new hydrotreating, reforming and catalytic cracking units reduced lead and sulfur in refined products. 

This section covers recent advances in the application of three-phase fluidization systems in the petroleum and chemical process industries. These areas encompass many of the important commercial applications of three-phase fluidized beds. The technology for such applications as petroleum resid processing and Fischer-Tropsch synthesis have been successfully demonstrated in plants throughout the world. Overviews and operational considerations for recent improvements in the hydrotreating of petroleum resids, applications in the hydrotreating of light gas-oil, and improvements and new applications in hydrocarbon synthesis will be discussed. 

The applications of butene-1 usually require very low levels of isobutylene and butadiene. Sometimes an extra reactor in the MTBE plant is added to get the isobutylene content down from the typical 2.0% to a 0.2% level. Small amounts of butadiene are removed by hydrotreating the stream over a catalyst, which converts the butadiene to butene-2 and maybe some butane. 

The process considered is the Colony hydrotreated shale oil plant using the TOSCO II pyrolysis retort (4). In this process raw shale, crushed to 1/2" or smaller, is contacted with hot ceramic balls in a rotating drum. Downstream of the retort the balls and spent shale are separated by screening. The balls are then transported by an elevator to a vessel in which they are reheated by direct contact with hot combustion gases. The heated balls are then recycled to the rotating retort. 

The plant will produce 198 TPSD of elemental sulfur. This represents a sulfur output of 0.0045 tons of sulfur/barrel of hydrotreated shale oil. 

Currently, delayed coking and fluid coking are the processes of choice for conversion of Athabasca bitumen to liquid products. Both processes are termed the primary conversion processes for the tar sand plants in Ft. McMurray, Canada. The unstable liquid product streams are hydrotreated before recombining to the synthetic crude oil. 

If the SRC-II is hydrotreated at an intermediate or moderate severity, further processing will be necessary to upgrade the product to specification transportation fuels. A number of pilot plant tests have been made to determine the conditions and to demonstrate the feasibility of these processing steps. 

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