H-Coal reactor

In addition to the content of ion-exchangeable calcium, other factors must be considered when the rate of accumulation is in question. In order that the precipitates be retained in reaction vessels, it is necessary that they grow to a sufficient size to preclude elution. This condition is achieved in reactor configurations where residence time is relatively long. Alternatively, if turbulent conditions prevail, as in the H-Coal reactor, the precipitates may be abraded or not allowed to grow, so that retention would be inhibited, though their formation will not be prevented. 

Vasalos, I. A., E. M. Bild, D. N. Rundell and D. F. Tatterson. Experimental Techniques for Studying the Fluid Dynamics of the H-Coal Reactor. Coal Processing Technology V6 (New York, AIChE J., 1980, pp. 226). 

The development of three-phase reactor technologies in the 1970 s saw renewed interest in the synthetic fuel area due to the energy crisis of 1973. Several processes were developed for direct coal liquefaction using both slurry bubble column reactors (Exxon Donor Solvent process and Solvent Refined Coal process) and three-phase fluidized bed reactors (H-Coal process). These processes were again shelved in the early 1980 s due to the low price of petroleum crudes. 

The H-Cocd Process, based on H-Oil technology, was developed by Hydrocarbon Research, Inc. (HRI). The heart of the process was a three-phase, ebullated-bed reactor in which catalyst pellets were fluidized by the upward flow of slurry and gas through the reactor. The reactor contained an internal tube for recirculating the reaction mixture to the bottom of the catalyst bed. Catalyst activity in the reactor was maintained by the withdrawal of small quantities of spent catalyst and the addition of fresh catalyst. The addition of a catalyst to the reactor is the main feature which distinguishes the H-Coal Process from the typical process. 

In ebullating bed reactor, such as the H-coal process, Ni-Mo or Co-Mo alumina catalysts have been used (96). The catalyst definitely improves the oil yields by accentuating aromatic hydrocracking, achieving conversions around 95% at catalyst make-up rates of 1 3%. 

Exxon Donor Solvent, and SRC-II, reactors are run at high severities to maximize distillate yield. Then, in the case of the H-Coal and SRC-II processes all the vacuum tower residue is sent to a partial oxidation gasifier to produce hydrogen. The amount of residue is set by the amount of hydrogen to be generated. The Exxon Donor Solvent process differs in that all or part of the vacuum tower residue is processed in a Flexicoking unit to recover additional liquids and to produce low Btu fuel gas. Partial oxidation can be used to process the remainder of the bottom to produce hydrogen. 

The reactor is the key to the versatility of the H-Coal process. Figure 3 is a simplified diagram of the reactor. The concept involves a catalyst bed that is kept in an expanded or ebullated state by charging the feed and additional recycle oil to the bottom of the reactor. The products, including unreacted coal and ash, flow through the catalyst and are removed from the reactor at a point above the top of the catalyst bed. An external separator removes gaseous products and recycle hydrogen from the liquid. 

PANELIST WOLK They have been looking for deposits of calcium processing Wyoming coal. I think there have been some very small concentrations of oolite, like structures found in the residues that have been looked at. Obviously, some of the calcium ends up on the catalyst, but it is a small proportion. The wall deposits have been checked for calcium concentration and they have been minimal. Whether that is a function of the reactor diameter using the PDU, the turbulence of the bed or really a lack of detailed observation, I don t really know. But it has not proved to be an operating problem with the H-Coal process. The period of time covered with subbituminous coal runs have been as long as thirty days. 

H-Coal (Hydrocarbon Research, Inc.)—catalytic hydrogenation of coal in an ebulliated bed reactor (Syncrude mode), 80.3 wt % on dry Illinois 6 coal, 1 part distillate of < 10 cP and 2 parts high mp solid containing 32 wt % solids. 

The H-Coal Process. The H-Coal process is an adaptation of the H-Oil process, which uses a catalytic ebullated bed reactor to... 

Figure 19.21 shows a schematic of the H-Coal process, which employs a single catalytic stage to produce a synthetic crude oil.37,38 Coal is crushed, dried, and mixed with recycle oil and hydrogen before being preheated to approximately 850°F (454°C). The preheater effluent is fed to the bottom of an ebullated bed reactor. During operation, fresh catalyst (a cobalt-molybdenum extrudate) is fed to the top of the reactor, while spent catalyst is removed from the bottom to maintain constant reactivity and inventory. The upward flow of the coal slurry and hydrogen causes... 

The H-Coal process produces approximately 3-3.5 barrels of liquid product for each ton of coal.42 Tests showed that the process is best suited for high-volatile bituminous coal the use of low-rank coals significantly reduced throughput and distillate yields. The successful performance of the ebullated bed reactor in the H-Coal process led to its later use in two-stage liquefaction systems. 

Coal derived materials These products were obtained from our 1 kg h continuous reactor unit (7) as oils (X4 soluble) asphaltenes (tetralin soluble/X4 insoluble) preasphaltene (also known as asphaltol) (tetralin insolubles/tetrahydrofuran (THF) solubles) and THF insoluble materials for subsequent reactivity studies. 

---