H-coal syncrudes

Table VII shows the estimated yields from an SCT-SRC plus hydrotreating scheme along with published yields from SRC-I (5), SRC-II (6) and H-coal Syncrude (7) processes. The yields for the SCT dissolution operation at Wilsonville (8) are also included...

Table VII shows that the SCT-SRC plus upgrading yields significantly less gas and more liquid (residual material included) than the other processes. The hydrogen consumption in the two-step SCT process is higher than for the SRC-I process however, it is still lower than for the SRC-II process and significantly lower than for the H-Coal Syncrude operation.

The important properties of these syncrudes include the hydrogen content, boiling range, and impurities. Apparently, the type of coal greatly influences these properties. The Wyodak H-Coal syncrude is richer in hydrogen and contains fewer heteroatoms than the Illinois H-Coal syncrude. In contrast, the SRC-II syncrude contains the least hydrogen and the most... 

The Illinois H-Coal syncrude contains the greatest amount of iron. This iron could be from corrosion during processing or storage, rather than from the coal itself. We have observed high iron contents in California gas oils which contain acidic and corrosive oxygen. In California gas oils, the iron is soluble in the oil as iron naphthenates (iron salts of organic acids) ... 

The Illinois H-Coal and SRC-II syncrudes contain large amounts of chloride, 32 parts per million (ppm) and 50 ppm, respectively. The Wyodak H-Coal syncrude contains only 3 ppm. Because the exit line from the pilot plants which processed the SRC-II syncrude occasionally plugged with ammonium chloride, we water washed the Illinois H-Coal syncrude prior to hydrotreating. It is our understanding that chloride will be removed by water washing at a commercial coal liquefaction facility. 

Two proprietary Chevron catalysts were used in different pilot plant simulations of the syncrude hydrotreater ICR 106 and ICR 113. The ICR 106 catalyst contains nickel, tungsten, silica, and alumina and the ICR 113 catalyst contains nickel, molybdenum, silica, and alumina. An equal volume of inert, nonporous alumina was placed on top of the catalysts. This alumina served as a preheating zone. These catalysts operated satisfactorily for over one-half year (4000 hours) with the Illinois H-Coal syncrude. 

Figure 2. Simplified flow diagram refining of H-coal syncrude by high severity hydrotreating...

Yield periods for these three syncrudes, refined to specification jet fuel, are shown in Table III. Accurate yields of the very small 600° F- " portion were not determined for these periods. The yields in Table III show this cut combined with the jet cut. The yield of the 600° F- " cut is approximately 5 vol % for the Illinois H-coal syncrude and 2.5 vol % for the Wyodak H-Coal and SRC-II syncrudes. Properties of the jet fuels are shown in Table IV. 

Illinois H-Coal Syncrude Wyodak H-Coal Syncrude SRC-II Syncrude ... 

For jet fuels, a visual rating of No. 1 or No. 2 is required at 260°C in the jet fuel thermal oxidation stability test (JFTOT-ASTM D 3241). Also, a pressure drop of less than 25 mm Hg is required in this test, As shown in Table XI, the 250°F+ product from hydrotreated Illinois H-Coal syncrude passes both parts of the JFTOT test, even when the jet fuel is not refined enough to pass three other specifications aromatic content, smoke point, and gum content. When jet fuels are prepared from coal-derived syncrudes, the smoke point appears to be the limiting specification. The gum content and end point specifications are met when the jet fuels are distilled at 600°F. 

Diesel fuel and heating fuels should pass both oxidation and thermal stability tests. As shown in Table XII, the raw Wyodak H-Coal syncrude has a very poor oxidation stability but the hydrotreated Wyodak H-Coal syncrude has an excellent oxidation stability. The oxidation stability of hydrotreated Illinois H-Coal products is also excellent, even without additives. 

TEST FUEL STABILITY TEST RESULTS FOR ILLINOIS H-COAL SYNCRUDE HYDROTREATED AT TWO SPACE VELOCITIES ... 

The whole Illinois H-Coal syncrude was redistilled at 600°F cut point to yield a rerun Illinois H-Coal syncrude and distillation bottoms (Table XIII). The yield of the rerun syncrude is 83.3 wt % (87.1 vol %). Although the nominal cut point of the distillation was 600°F, the products appear to be cut at close to 550°F. The distillation bottoms could perhaps be used to manufacture hydrogen by partial oxidiation or used as refinery fuel since it contains only 0.18 wt % sulfur. 

As shown in Figure 5, the rerun Illinois H-Coal syncrude is amazingly easy to hydroprocess, when compared to the whole... 

PROPERTIES OP THE RERUN ILLINOIS H-COAL SYNCRUDE AND DISTILLATION BOTTOMS... 

Illinois H-Coal syncrude. The product from the syncrude hydrotreater contains less than 5 vol % aromatics, even at 1.5 LHSV. 

The yields from the rerun Illinois H-Coal syncrude are shown in Table XIV. Properties of the jet and diesel fuels are shown in Tale XV. The 250°F+ product from the rerun Illinois H-Coal syncrude meets all jet fuel specifications without additional distillation. 

Rerunning these syncrudes appears to have three advantages. The size of the Illinois H-Coal syncrude hydrotreater can be reduced, perhaps to one-third of the original size. Distillation of the hydrotreated syncrude to meet jet fuel gum and end point specifications can be eliminated. Hydrogen can be manufactured from the least valuable component of the syncrude. 

When 15 vol % of the bottoms is removed from the Illinois H-Coal syncrude, the rates of the hydrotreating reactions are increased. The rerun Illinois H-Coal syncrude can be refined to jet or diesel fuel in a unit one-third of the size needed for the whole Illinois H-Coal syncrude. 

PROPERTIES OF JET AMD DIESEL FUELS MADE FROM RERUN ILLINOIS H-COAL SYNCRUDE... 

---