Shale oil reactor

Hum gas is inert, so leaks are not radioactive. The heat could also be used to refine shale oil or desalinate water. Each day about 3,000 pebbles are removed from the bottom as some fuel is spent from the 360,000 pebbles, so there is no need to shut down the reactor to replace fuel. The pebbles are fireproof and extremely difficult to turn into weapons. If the fuel gets too hot, it begins absorbing neutrons, shutting down the reactor. 

Figure 17.29. Moving bed reactors for cracking and recovery of shale oil. (a) Kiviter retort, USSR 200-300 tons/day [/. W. Smith, in Meyers (Ed.), Handbook of Synfuels Technology, McGraw-Hill, New York, 1984], (b) Paraho retort for shale oil recovery (Paraho Oil Shale Demonstration, Grand Junction, CO).

The chief examples are smelting for the recovery of metals from ores, cement manufacture, and lime burning. The converters, roasters, and kilns for these purposes are huge special devices, not usually adaptable to other chemical applications. Shale oil is recovered from crushed rock in a vertical kiln on a batch or continuous basis—moving bed in the latter case—sometimes in a hydrogen-rich atmosphere for simultaneous denitrification and desulfurization. The capacity of ore roasters is of the order of 300-700 tons/(day)(m3 of reactor volume). Rotary kilns for cement have capacities of 0.4-1.ltons/(day)(m3) for other purposes the range is 0.1-2. 

This first run with ICR 106 catalyst was shut down at 2000 hr on stream when a plug consisting of iron and arsenic deposits from the shale oil developed in the preheat section of the reactor. (In this first test, a guard bed to remove these metals was not provided.) To prepare sufficient feedstock for downstream processing studies, a larger-scale, 3500-hr pilot plant run was made with 650 mL of ICR 106 catalyst-. 

Shah and Paraskos47 applied their analysis to evaluate the importance of axial dispersion on pilot scale (a) residue hydrodesulfurization, (b) gas-oil hydrocracking, and (c) shale-oil denitrogenation reactor performances. The calculations indicated that the axial dispersion effect is less important in case (c) than in cases (a) and (b). Under certain pilot-scale operations, axial dispersion effects could be significant in cases (a) and (b). 

Chapters 10-12 cover important aspects of coke formation in metal tubular reactors during pyrolysis of hydrocarbons. Chapters 13 and 14 are concerned with coal and lignite pyrolysis. Chapters 15 and 16 deal with pitch formation from, respectively, heavy petroleum fraction and tar sand bitumen. Chapters 17 and 18 cover studies on the mechanisms of thermal alkylation and hydropyrolysis. Chapters 19 and 20 on oil shale deal with the properties of oil shale and shale oil as developed by techniques of microwave heating and thermal analysis. 

Kinetic Measurements. The results of the shale oil cracking experiments are summarized in Table I. Oil yields are reported as a percentage of the LLNL assay result on both a condensed-oil basis and a C5+ basis. To conduct the kinetic analysis, an effective residence time had to be determined. It was assumed for simplicity that the gas-and-oil evolution profile could be approximated by a square pulse. The average residence time was calculated by multiplying the void volume of the bottom reactor by the time interval over which three-fourths of the products were evolved and then dividing by the total volume of gases and vapors at the cracking temperatures (14). The void volume was... 

Two additional cautions should be mentioned concerning the use of Equation (3). Experiment 125 (no shale in the bottom reactor) was used in neither kinetic analysis because the conversion was substantially lower than expected on the basis of the other experiments. This discrepancy may have resulted from either a catalytic effect of the shale or a heat-transfer limitation. In addition, Dickson and Yesavage (19) found that there is a 60 to 70% conversion limit for shale oil cracking. 

Table II gives the product distribution for thermal cracking of shale oil. We defined oil as the sum of condensed oil and C5-C9 hydrocarbons in the gas. The amount of each gaseous product was determined from the slope of the curve plotting gas production versus cracking loss (conversion) (14). The amount of coke produced was determined by difference, but it agreed well with the measured value for the few experiments in which carbon was analyzed in the shale from the bottom reactor. The alkene/alkane ratios in the gas depended more strongly on the cracking temperature than on the extent of conversion. This topic is discussed in greater detail in another paper published in these proceedings (20).

Figure 3. The effect of oil cracking on the H/C atomic ratio and nitrogen content of the shale oil. The data points indicate cracking over burnt shale (O), retorted shale (%), and in an empty reactor ([J). The H/C ratio is probably a function of both cracking temperature and loss. Aromatic nitrogen compounds are concentrated selectively by cracking.

Petrosix [Named after the oil company Petrobus and the oil shale company superintendencia de industrializacao do xisto] A pyrolytic process for extracting petroleum from shale, developed in Brazil since 1953. A large demonstration plant was operated in Brazil in the 1970s. The world s largest oil shale pyrolysis reactor is in Sao Mateus do Sul, Brazil. It uses a vertical pyrolysis reactor. By 2008, it had produced 20 million bbl of shale oil. Sulfur is a by-product. Operated by Petrobras. 

Moving bed reactors for oil recovery from shale is one example of this kind of operation. Another somewhat analogous operation is the multistage counterflow reactor, and the four- or five-stage fluidized calciner is a good example of this. In all these operations the efficiency of heat utilization is the main concern. 

Energy sources and conversion— biomass, batteries, fuel celts and fuel cell technology, hydrogen as a fuel, liquid and gaseous fuels from coal, oil shale, tar sands, nuclear fission and fusion, lithium lor thermonuclear reactors, insulating materials, and solar energy. 

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