Liquefaction reactor

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. 

In Wilsonville Runs 143 and 147, thermal degradation of the coal-derived products greatly affected the SRC recovery on the Rerr-McGee CSD Unit. Both runs were made at identically the same operating conditions, except in Run 143, where presumably catalytically active solids were allowed to accumulate in the liquefaction reactor, whereas in Run 147 the solids were removed. The product yields exiting the reactor for both runs were very similar however, the thermal sensitivity of the... 

Tarmy, B. L., Chang, M., Coulaloglou, C. A., and Ponzi, P. R., The Three-Phase Hydrodynamic Characteristics of the EDS Liquefaction Reactors Their Development and use in Reactor Scaleup, Proc. 8th Int. Symp. Chem. Reaction Eng., 30 239 (1984)... 

Catalytic coal liquefaction processes do not specifically use hydrogen donor solvents although coal is introduced into the liquefaction reactor as a slurry in a recycle liquid stream. Catalyst is used as a powder or as granules such as pellets or extrudates. If powdered catalyst is used, it is mixed with the coal/liquid stream entering the reactor. Pelleted catalyst can be used in fixed bed reactors if precautions are taken to avoid plugging with solids or in fluidized bed reactors. In the latter case, the reacting system is actually a three phase fluidized bed, that is, catalyst particles and coal solids, as well as liquid, are fluidized by gas. 

The reactor effluent is separated by conventional distillation into recycle solvent, light gases, C4 to 537°C bp distillate, and a heavy vacuum bottoms stream containing unconverted coal and ash. The recycle solvent is hydrogenated in a separate reactor and sent back to the liquefaction reactor. 

The schedule leading to mechanical completion in the fourth quarter of 1979 is shown in Figure 3. The control house is scheduled for completion in May. Final electrical facilities including substations and interplant lines are scheduled for completion in June. Coal preparation facilities and operational tankage are to be commissioned in August followed by completion of the solvent hydrogenation section in October. Final mechanical completion will be accomplished with turnover of the liquefaction reactor and fractionation sections, and is projected for mid November. 

Analyses of coals which have been processed in the continuously operated pilot plants are listed in Table 1. Process liquid yields from the liquefaction step for these coals are shown in Figure 4 for different residence times in the liquefaction reactor. Longer residence time increases conversion of coal to liquids, but also increases hydrocracking of liquids to gas. 

The high calcium content of the younger coals has led to the formation and deposition of calcium carbonate in the liquefaction reactor in the form of wall scale and oolites which were first observed in German operations (10). These deposits form as calcium salts of humic acids in the coal decompose under liquefaction conditions. The deposits continue to grow with time and could lead to unwanted solids accumulation in the reactor itself as well as fouling of downstream equipment (11). Data shown in Figure 7 indicate the accumulation rate of the calcium carbonate in the liquefaction reactor for different coals under typical EDS conditions as well as two methods for controlling the solids build-up. 

One method of control is to use solids withdrawal from the liquefaction reactor coupled with strainers upstream of critical equipment such as valves, instruments, and pipe bends. In addition, reactor cleaning by chemical means during normal reactor turnarounds would be used to insure the required onstream time. 

H. SIEGEL Bruce, along similar lines, can you say anything about the hydrogen treat rate that goes into the liquefaction reactor as a percent of coal feed or any other basis ... 

A question of considerable interest in coal hydroliquefaction chemistry is the amount and nature of "organically bound metals in the coal. One reason for this interest is the observation that when supported metal direct conversion catalysts are used in liquefaction reactors, a primary mode of deactivation is metals deposition Q, 2). In particular, recent work at the Pittsburgh Energy Technology Center (PETC) (4,5) and elsewhere (3) has indicated very high levels of titanium deposition on supported Co Mo catalysts used in the fixed bed continuous reactor system. It has been suggested that the culprits in such deposition are soluble metal species (6 9) The analyses of a Western Kentucky (Homestead) hvBb feed coal and of material deposited between the catalyst pellets in the fixed bed reactor at PETC (4) are shown in Table I. 

Operating conditions for the EDS process are similar to those for the SRC-II process and, like SRC-II, EDS works best with bituminous coals. The distillate yield is about 2.5-3 barrels of liquid per ton of coal. This somewhat low yield is probably attributable to the absence of a catalyst in the liquefaction reactor. 

For a three-phase fluidized-bed coal-liquefaction reactor, estimate... 

As can be seen in the NEDOL process in Figure 12.4, pulverized coal and 2% 4% by weight iron-based catalysts are first slurried together with recycled solvents. The slurry is mixed with H2 and preheated before it is delivered to the liquefaction reactor. The tubular up-flow reactor typically operates at temperatures of... 

Ruynal, J., Delgenes, J. P., and Moletta, R. (1998). Tow phase anaerobic digestion of solid waste by a multiple liquefaction reactors process. Bioresour. Technol. 65, 97-103. 

A related reactor is that for coal liquefaction, which can be carried out in a three-phase slurry bubble column (see Fig. 5). Hydrogen can be supplied at the bottom of a column of downcoming product—oil. The solid coal reactant is blended with the product or carrier oil and fed at the top. The generic process depicted in Fig. 5 is a generalization of the liquefaction reactor in the Exxon Donor Solvent Process. As the gas flow rate increases, the bubbles change from uniformly small to chaotic. In the H-coal process, both the gas and a coal-oil slurry are fed from the bottom in an ebullating-bed reactor. Catalyst solids are fed from the top. This reactor operates as an expanded... 

The PIPU is a pilot plant system built in the early 1980s for studying a multitude of synthetic fuel/chemical processes. In the mid 1990s, a direct coal liquefaction reactor within the PIPU plant was reconfigured as a SBCR for FTS studies (see Figure 1.). The reactor was originally designed to operate with coarse catalyst pellets (>500 pm). Consequently, the reactor system did not contain a wax separation system sufficient for smaller catalyst particles that are typically used in FTS. Therefore, a slurry accumulator and a batch wax filtration system were installed. 

During the period from 1995-96, attempts to operate the direct liquefaction reactor in a F-T mode were successful in that a clear wax product could be obtained. However, the initial activity observed in the bubble column was about 10-15% less than that of comparable CSTR... 

Bergius (original process developed early 1900s) Iron oxide 465 200 H2 in liquefaction reactor Most severe conditions catalyst discarded... 

Solvent Refined Coal (Gulf Oil) Minerals in coal (none added) 450 140 H2 in liquefaction reactor Recycle of portion of product liquid to reactor lack of hydrogenation specificity... 

H-Coal (Hydrocarbon Research Inc.) CoO—M0O3/AI2O3 450 200 H2 in liquefaction reactor Catalyst ages rapidly... 

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