Coal tar is a byproduct of the production of coke from coal. Coke is the solid residue (mostly carbon) resulting from destructive distillation (heating in absence of air; "pyrolysis," "carbonization") of a coal or petroleum.
Coke. Coke is already produced down-time for use as a fuel. Early on, the up-timers will point out that coke can be used, in place of charcoal, as the fuel and reducing agent for a blast furnace. (As EA points out, coke is mechanically stronger than charcoal, and thus can support a larger charge.) This can be expected to lead to an increased demand for coke.
The up-timers know of the relationship among coke production, steelmaking, and the organic chemical industry. Josh and Colette Modi are visited by the metal magnate Louis de Geer (Colette's uncle) in April 1632, and they suggest to him that "given the chemicals that can be distilled from coal tar gases when making coke, a chemical company might be very profitable." Mackey, "The Essen Steel Chronicles, Part 2: Louis de Geer," Grantville Gazette 8.
The down-timers produce coke in crude beehive ovens, which wastefully allow the liquid and gaseous byproducts to escape. EA/Coke has a surprisingly detailed description of both the old-fashioned beehive ovens, and "byproduct ovens" designed to capture all of the byproducts. In the old timeline, the first such oven was built in 1881.
The carbonization temperature has a large influence on the nature of the products. If the temperature is less than 200oC, they are mainly methane, water and carbon dioxide. In the range 200-400oC, the methane is replaced by carbon monoxide. Passing beyond 400oC, hydrogen begins to appear and once you exceed 800oC, it is the main gaseous product. Only the coke produced by high temperature carbonization (over 800oC) is used for metallurgical purposes (EA/"Coke"). EB15 says 900-1200oC, with the low end for making town gas and the high end for metallurgical coke.
Coal Tar. All of the coal products, save for the coke, are initially part of the coke oven gas. As the coke oven gas is cooled, the components which are solid ("crude tar") or liquid ("ammoniacal liquor") at room temperature are separated from the light gas. Then the ammoniacal liquor is decanted from the tar, and the latter is distilled.
EB11 warns that the tar must be dehydrated before distillation. It's then pumped into a tar still. In OTL, 3-6 distillation fractions were taken. The "Grantville literature" refers to four such fractions—light ("benzoil"), middle ("carbolic") , heavy ("creosote") and anthracene ("green")—leaving a residue of pitch. The distilleries varied with respect to the precise distillation temperatures and specific gravities by which these fractions were defined, and this naturally also affects their relative proportions and composition. See Fig. 4-1 (EA; Shreve 84) for one example; others in Appendix.
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Figure 4-1 Coal Pyrolysis Products
The fractions (which are complex mixtures) may be used as is (e.g., as solvents), or subjected to further work up as described in EB11/Coal Tar:
Light Oil: (1) extract tar acids (phenol, cresols) with caustic soda, (2) extract tar bases (pyridine) with dilute sulfuric acid, (3) remove some aliphatic hydrocarbons with concentrated sulfuric acid, and (4) steam distill to obtain benzene, toluene, xylenes, and cumenes.
Middle and Heavy Oils: (1) crystallize out naphthalene, and (2) recover the tar acids and bases.
Green Oil: (1) crystallize out anthracene, redistilling if need be; (2) extract phenanthrene with naphtha, (3) extract carbazole with pyridine.
There are hundreds of chemicals in coal tar, and the amount of each depends on the coal and how it's processed. There is quantitative data, sometimes contradictory, in Grantville Literature (McGHEST, EA, EB15, M&B373, EB11/Coal Tar; see Appendix). While not part of that literature, reasonable production estimates would be:
benzene, toluene, xylene: 1-2.5% (in proportions 6.67:2:1 per EB11)
naphthalene 4-10%
anthracene 0.25-2%
phenol 0.4-0.5%
cresols 2-3%
pyridine and quinoline 0.2-0.3%
creosote oil 25-30%
pitch 50-60%
(Chamberlain 500)
A coal gas plant opened in Magdeburg in November 1633 (Flint, 1634: The Baltic War, Chapter 2). Its gas was used for lighting and heating. From chapter 3, we know that the furnace was hot enough to generate hydrogen gas. The Magdeburg plant separated the coal tar into different products, including pitch and "light benzoils" (benzene and related compounds). Production was such that it generated a barrel or two of the light benzoils every day. It also produced ammonium nitrate for use as fertilizer. (Ammonium sulfate can be recovered from the ammoniacal liquor; figure 10 kg/metric ton coal; McGHEST.)
Coal Gasification. Since World War II, there have been efforts to convert coal into a fuel gas (EA/"Coal Gasification"). Depending on the precise process used, the gas can have a high or a low heating value, the latter having the advantage of a low sulfur content. The low BTU gas, curiously, has been made at a plant in Morgantown, West Virginia, and it is possible that some of the Grantville residents have read about its operations or even worked there.
From our perspective, a more interesting form of coal gasification is the older (Twenties) use of coal to make "synthesis gas" (syngas), a mixture of carbon monoxide and hydrogen. I discussed this in part 3.
Coal Liquefaction. The purpose of coal liquefaction is to convert the solid hydrocarbons into ones liquid at room temperature, especially those in the gasoline size range. The usual use of the liquefaction product is as fuel, but in theory the compounds could instead be used as starting materials in organic synthesis.
Coal gasification and liquefaction are advantageous if coal is cheap and petroleum is expensive.
Natural Gas Feedstocks
Natural gas is potentially an important industrial source of the lower molecular weight alkanes, notably methane, ethane, n-propane, isopropane, n-butane and isobutane. These can be separated by fractional distillation.
We know that the residents of Grantville have made an effort to switch from gasoline to natural gas (and alcohol) as fuel for their vehicles.
Many natural gas wells can be found in Grantville. The town is heated with local natural gas, and Willie Hudson runs his farm off gas from his own land (Flint, 1632, Chapter 8). There are also wells on the properties of "Birdie" Newhouse. (Huff and Goodlett, "Birdie's Farm," (1634: The Ram Rebellion), George Blanton (Jones, "Anna's Story," (Grantville Gazette 1), and John and Millie. (Huston, "Seasons," Grantville Gazette 7), and unnamed others.
Under West Virginia law, a "gas well" is a well which has an initial production such that the gas-oil ratio (GOR) is at least 6,000 cubic feet of gas for each barrel of oil. (The two then have the same energy value.) Since these gas wells in Grantville were not in commercial production at the time of the Ring of Fire, they probably fall into the category of stripper wells. A stripper well is defined by Interstate Oil and Gas Compact Commission as one producing not more than 60,000 cf gas or 10 barrels oil/day. But the average production for marginal wells in West Virginia was 0.6 barrels oil or 11,000 cf gas/day. (IPAA2004).
Natural gas is often trapped near petroleum. It may be produced ("dry gas") from a pure gas well (which in turn is tapping a gas cap above the oil horizon), from a gas-condensate well (so-called because some of the gas condenses when brought to the surface), or from an oil well, dissolved ("wet gas") in petroleum. Generally speaking, in "dry gas", methane is 70-98%, ethane 1-10%, propane 0-5%, butane 0-2%, and in wet or condensate gas, methane 50-92%, ethane 5-15%, propane 2-14%, butane 1-10%. (Rojey 80). The propane and butane are called "petroleum gas."
A 1904 analysis of natural gas from Fairmont, West Virginia reported 81.6% methane, 14.09% ethane, 3.21% nitrogen, and 0.2% heavier hydrocarbons, and Morgantown gas was similar. (UGSK 242). Hence, I think we must assume production of propane is under 0.1%.
German natural gas may not be much better as a source of propane. The natural gas produced in Neuengamme, Germany in 1910 was 91.6% methane, 0.8% heavy hydrocarbons. (Molinari, 36).
Petroleum Feedsto
cks
Petroleum contains a greater variety of organic compounds than does natural gas.
Fractional distillation separates the petrochemicals more or less by carbon number (Table 4-1A). To separate one class of hydrocarbon from another (e.g., aromatics vs. aliphatics), you need to use a selective solvent. The solvents used include liquid sulfur dioxide, liquid propane, furfural, and phenol (EA/Petroleum, Furfural).
Our initial sources of petroleum are the natural gas wells in Grantville. 1633 chapter 34 says that they were "upgraded" to produce what Mike calls a "fair amount," and Quentin, a "trickle," of oil. The implication is that the gas wells are what are sometimes called "condensate wells." Condensates are hydrocarbons, heavier than butane, which occur naturally in gaseous form in the reservoir, but which condense (liquefy) in the reservoir (after drilling), at the wellhead, or in a field separator, and can thus be separated from the natural gas. A typical composition is 40-90% C7-C8, 10-20% C9, 1-15% C6, 3-10.5% C5, and 0-4% hydrogen sulfide. (Marathon).
As for oil wells, oil composition varies from field to field, from well to well, and from formation to formation. Oils are classified as light, medium or heavy, based on their density. As you might expect, the light oils are rich in the volatile, low carbon number compounds, whereas the opposite is true of the heavy oils. The oils are mostly hydrocarbons, but include small amounts of compounds containing oxygen, nitrogen and sulfur. Oils with a low sulfur content are said to be "sweet", and those with a high content are labeled "sour." Heavy oils tend to be sour, too.
Pennsylvania oils are of the simple paraffin type (primarily linear alkanes), whereas Caucasian petroleums are more complex. (EB11 and EA "Petroleum"). At least some of the oils of Oelheim and Wietze are naphthene/asphalt type. (Bacon 888). These have a lower alkane content, but compensate by being richer in cycloalkanes (naphthenes), alkenes (olefins) and aromatic compounds (e.g., benzene, naphthalene, anthracene). They are more chemically reactive, hence more versatile, than alkanes.
By 1633, the up-timers are collecting oil at Wietze. Wietze is actually one of a dozen or so small oil fields near Hanover, and it is only a matter of time before others are discovered.
For the composition of Wietze heavy (shallow) and light (ca. 1000') oil, see Table 4-1B. In general, it's good for the organic chemical industry, not so good for automobiles.
Petrochemical Conversion. Initially, oil wells were drilled to obtain kerosene for use as in illumination and heating. When the automobile became popular, the emphasis switched to gasoline, especially the lighter "straight run" component (distilling at 20-150 oC). With the advent of high compression ratio engines, the heavier naphthas (150-200 oC) became more popular.
Up-time, the demand for gasoline had been great for many years, and hence processes were developed, and integrated into refinery operations, for converting heavier or lighter fractions into the hydrocarbons most suitable for auto engines. (Wittcoff).
There are three methods of down-converting. Thermal cracking uses high pressures and temperatures (exceeding the boiling points of the target hydrocarbons at the process pressure) to break carbon-carbon and carbon-hydrogen bonds, converting the heavier fractions into C5-C12 aliphatics, and in the process also converting some alkanes into alkenes M&B 138 says the main product is ethylene. There is some discussion of thermal cracking methods in EB11/Petroleum. EA/Cracking recommends 482-538 oC and 206-735 psi.
Steam cracking features mixing the hydrocarbons with steam, flash heating to 700-900 oC, and then quenching. This produces additional alkenes (ethylene, propylene, butadiene, isoprene, cyclopentadiene).
Catalytic cracking requires less vigorous conditions. EA/Cracking says "catalysts originally used were bentonite clays, but now pellets or granules of alumina, silica, zirconia, or magnesia, or artificial mixtures of these materials are more commonly used." The catalytic cracking is conducted at 427-482 oC and 10.3-29.4 psi (14.7 psi is normal atmospheric pressure). Catalytic cracking yields heavily branched alkanes and alkenes.
The heaviness of Wietze oil, and many other German oils, provides an incentive to develop these cracking processes, especially catalytic cracking, to provide more gasoline.
We can also up-convert the lighter hydrocarbons. The classic approach was to polymerize olefins using acid catalysts, and it was "neither easy nor inexpensive." Nowadays, it is more common to "alkylate", which in this context means to react an olefin with a paraffin to obtain a larger, branched hydrocarbon. It, too, uses an acid catalyst, usually concentrated sulfuric acid or hydrofluoric acid (EA/Petroleum).
These methods beg the question of how we obtain the olefins. It is likely to be a two step process, converting the alkanes into alkyl chlorides or alcohols, and then those intermediates into alkenes.
Up-conversion hurts the organic chemical industry by converting hydrocarbons which it might otherwise use as feedstock into gasoline for fuel use.
Catalytic reforming (1940s) cyclizes (makes open chains into rings), isomerizes (straight chains to branched), and dehydrogenates. The dehydrogenation generates alkenes and aromatics. While they are good for cars, they are great for the organic chemical industry. Indeed, catalytic reforming is what made it possible for the petroleum industry to overtake the coal industry as a source of benzene, toluene and xylene ("BTX"). Morrison & Boyd (373) say that catalytic reforming requires high temperature and pressure, and a platinum catalyst, but that's it. There are basic organic chem texts which provide more information; Bordwell (381) refers to use of 0.75% platinum on alumina, 450 oC, and 500 psi hydrogen.
A lot of experimentation will be needed to make any of these conversion methods commercially viable.
Botanical Feedstocks
Plants are a source of carbohydrates (simple sugars, starch, cellulose, carbohydrate gums), protein, fats, resins, and exotic secondary metabolites. The secondary metabolites are usually present in just small quantities but there are exceptions. Quinine is up to 8% of quinine bark; morphine, 16% opium; theobromine, 1.2% cacao bean; diosgenin, 5%, Mexican yam. (SzmantIURR 142, 166ff). Fifteen tons of dried Madagascar periwinkle leaves are needed to produce one ounce of vinblastine, and it takes the bark of more than one Pacific yew tree to yield one gram of anti-cancer taxol. (National Botanic Garden)
The chemical makeup of plants varies from species to species, and is also affected by growing conditions (climate, soil or water, pest activity) and developmental stage. Both land plants and marine plants can be of interest.
The distribution of the chemicals isn't uniform within the plant; a chemical of interest may occur preferentially in the seeds, fruit, roots, leaves, flowers, stem, buds or branches of the plant. It can be in solid tissue, or in a liquid (saps, resins, latex, etc). In the stems of woody plants, the chemistry of bark, heartwood, and sapwood can vary.
Agar. Agar is a galactose polymer derived from certain red algae and seaweed; "Grantville literature" calls attention to the Gelidium and, to a lesser extent, Gracilaria, Pterocladia, Acanthopeltis, and Ahnfeltia (EB11/Jams and Jellies; CCD; MI; EA, EB15).
I am not sure how much is known about the geographic distribution of these algae, but specialist literature shows that the closest source of Gelidium to the USE is in the coastal waters of northern Spain and Morocco; of Pterocladia, near the Azores; and Gracilaria, western South Africa. (FAO).
Cellulose and Derivatives. Cellulose is a glucose polymer and constitutes about 30% of all plant matter. The best sources are wood (~50% cellulose) and vegetable fibers. Cotton is about 91% cellulose. (Sadtler 275). Several fibers, of course, are used down-time to make textiles, rope and paper.
EB11/Cellulose says that cellulose can be obtained by treating cotton fiber with "boiling dilute alkalis, followed by chlorine gas or bromine water, or simply by alkaline oxidants. The cellulose thus purified is further treated with dilute acids, and then exhaustively with alcohol and ether." If you are making chemical filter paper, you also use hydrofluoric acid to remove silica.
Cellulose can be used to make
methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, cellulose nitrate, cellulose acetate, cellulose proprionate, cellulose xanthate and other cellulose derivatives. EA "Cellulose" is a good source of information on how to make them.
Cellulose nitrate was an early explosive and also an early photographic film base. It is made by treating cellulose with a mixture of nitric and sulfuric acids, and then adding camphor as a plasticizer. Cellulose acetate is used to make rayon. The cellulose is treated with acetic anhydride. Similarly, cellulose propionate is made by treating the fibers with propionic anhydride. Cellulose xanthate is used to make viscose rayon, cellophane film, and cellulose sponges. Making the xanthate requires sodium hydroxide and carbon disulfide.
Oxidative degradation of cellulose yields , depending on conditions, acetic, butyric, oxalic and levulinic acids. (EB11; SzmantIURR 90).
In wood, the cellulose is accompanied by lignin (25%) and hemicellulose (25%). In papermaking, the lignin is disintegrated by the Kraft process (sodium hydroxide and sodium sulfide), or with sulfites or bisulfites.
Lignins. Lignins, which are complex polymers, produce different products, depending not only on their source but how they are isolated. Lignosulfonates and "alkali lignins" are byproducts of acidic and basic wood pulping, respectively. Either can be used to make dimethyl sulfide, which is oxidized to yield the special solvent dimethyl sulfoxide. Lignins can be converted to phenols (Wittcoff 161), such as vanillin (via nitrobenzene). (SzmantIURR 154ff).
Hemicelluloses. These are polymers composed of several sugars, particularly xylose.
The sugars are released by hydrolysis, and xylose can be hydrogenated into the sweetener xylitol (SzmantIURR 99). Under more stringent hydrolysis conditions, the xylose is converted to furfuraldehyde or furfural (100). Furfural is used to make furfural-phenol plastics.
Grantville Gazette Volume 27 Page 18
