http://www.anl.gov/PCS/acsfuel/preprint%20archive/Files/39_4_WASHINGTON%20DC_08-94_1146.pdf
We have earlier, and will further, document and attempt to describe Shell Oil's "MDS", Middle Distillate Synthesis, technology for the conversion of hydrocarbon gasses into hydrocarbon liquid fuels, especially with regards to it's reduction to commercial practice at Bintulu, Malaysia.
Though most often associated with the catalytic transformation of natural gas into liquid hydrocarbons, it is planned at Bintulu, we believe, according to reports we've earlier relayed to the West Virginia Coal Association, for Shell's MDS technology to be deployed in conjunction with a lignite Coal conversion plant, using Shell's proprietary gasification technology, now under development according to other reports, to supply the needed Methane.
Other reports widely available indicate that the Methane is to be supplied by off-shore natural gas wells.
More on that issue follows our initial presentation from the above link. And, by way of foreword, keep in mind that we have documented to the point of it being indisputable that Methane can, in any case, be synthesized from both Carbon Dioxide, via Sabatier processing, and from Coal, via hydro-gasification.
As further explanation of Shell Oil's Middle Distillate technology, we submit excerpts from:
"Shell Middle Distillate Synthesis: The Process, The Plant, The Products
Author: Peter Tijm; Shell International Gas, Ltd.; London
Recognizing the growing importance of natural gas, Shell has been looking at other ways of using natural gas profitably, particularly those reserves which are remote from the market. The key elemeht is in the transportation aspect and so cost improvements to conventional pipeline and LNG schemes are being studied However, where such schemes will continue to make an important contribution to the natural gas trade, their end products (natural gas) are by nature confined to markets for natural gas Shell has therefore also been looking at processes that chemically convert natural gas into liquid hydrocarbons. Using such processes not only reduces the transportation costs substantially, but also a much larger market becomes available, especially if these hydrocarbons are transport fuels. Moreover, apart from providing a means to commercialize remote gas reserves, this could also serve to reduce the reliance on oil or oil-product imports and perhaps as important, save on foreign exchange.
("Foreign exchange" is something we should always keep in mind, relative to our vast transfer of wealth to OPEC, when we consider the true investment costs of Coal-to-Liquid development.)
It has been realized that there are many places in the world where gas is available, without a ready market and where, as a consequence, it would have a much lower intrinsic value compared with transportation fuels. It is this difference in value that would drive a synthetic fuel project and provide opportunities for both government and private enterprises.
Synthetic hydrocarbons ... have the advantage that they can be readily incorporated into existing fuels which can be used in existing equipment.
The SMDS process consists of three stages:
1. Syngas manufacturing
(And yes, of course, we can generate "syngas", synthesis gas, from Coal.)
The next step of the process, the hydrocarbon synthesis, is, in fact, a modernized version of the classical Fischer-Tropsch (FT) process, with the emphasis on high yields of useful products. The Fischer-Tropsch process developed by Shell for SMDS favors the production of long chain waxy molecules which, as such, are unsuitable for transportation fuels. The hydrocarbon synthesis step is therefore followed by a combined hydro-isomerization and hydrocracking step to produce the desired, lighter products. By opting for the production of waxy molecules in the Fischer-Tropsch step, the amount of unwanted smaller hydrocarbons or
gaseous products. produced as by-products, is substantially reduced. This means that the process, contrary to the old 1930s Fisher-Tropsch technology, can be fuel balanced and does not make "gas" out of gas. Combined with the high selectivity towards middle distillates in the hydrocracking step this leads to a very high overall yield of product in the desired range.
(We must emphasize that the "Fisher-Tropsch technology" used in the "1930s" was employed by Germany and Japan to make liquid fuels for their armies out of Coal.)
In the final stage of the process, the products, mainly kerosene, gas oil and some naphtha, are separated by distillation. By judicious selection of the severity of the hydrocracking reaction and the cut-points, the product slate can be biased towards kerosene or towards gas oil.
Synthesis Gas Manufacture
For the production of synthesis gas in principle two technologies are available, viz., steam reforming and partial oxidation.
Steam Reforming (SMR): Starting from pure methane, SMR is the most commonly used conversion process.
Because the H2/CO ratio in the synthesis gas is greater than 2, in the subsequent hydrocarbon synthesis step less hydrogen will be consumed than is produced in the syngas step. This means that steam reforming always results in the production of excess H2. An often practiced solution is to bum the surplus hydrogen in the reforming furnace. This means, however, that part of the synthesis gas is used as fuel.
Partial Oxidation: A synthesis gas suitable for the production of middle distillates ... can be produced by partial oxidation.
For the Fischer-Tropsch type of catalysts, the synthesis gas must be completely free of sulphur. For this requirement, it has been found to be economical to remove all sulphur components upstream of the partial oxidation step for which, in principle, a number of well-known treating processes are available. In practice, zinc oxide beds are employed, to remove the last traces of sulphur and to act as an absolute safeguard.
The Hydrocarbon Synthesis Step: In the next step, the synthesis gas is converted into long chain, heavy paraffins, and this step is therefore called the Heavy Paraffin Synthesis (HPS) step, the heart of the SMDS process.
The only product fraction ... which can be produced with high selectivity is heavy paraffin wax. It is for this reason that the synthesis part of the SMDS process has been designed to produce a long-chain hydrocarbon wax.
Shell has developed a new and proprietary catalyst system, which establishes substantial improvements in all these areas. Its robustness allows the use of a fixed bed pipe reactor system at a temperature level where heat recovery, via production of steam, leads to an efficient energy recovery. The catalyst, which is regenerable ... has an expected useful life of well over five years.
The principle of combining the length-independent chain growth process with a selective, chain-length dependent conversion process has been applied to selectively produce middle distillate paraffins from synthesis gas. To take full advantage of this concept, the Fischer-Tropsch catalyst and the operating conditions were chosen as to produce a heavy product with a high alpha-value, minimizing the formation of undesired light hydrocarbons. The effectiveness of the two stage approach also creates flexibility creating selective distributions of Fischer-Tropsch liquid products after heavy paraffin conversion at different cracking
severities.
As can be expected from a Fischer-Tropsch process of this type, products manufactured by the SMDS process are completely paraffinic and free from nitrogen and sulphur.
Because of these excellent properties, which are far in excess of the minimum specifications in terns of smoke point and cetane number, these products make excellent blending components for upgrading of lower-quality stock derived from catalytic and thermal cracking ... . Alternatively the products could enter in a market where Premium specifications are valued to meet local requirements. Examples include the
California diesel market, where the California Air Resources Board (CARB) has imposed a fuel Specification with low sulphur and aromatics and the Committee for European Norms (CEN) which has established a fairly high cetane number requirement.
(An) important factor is whether the products are for inland use or for export. For countries with sufficient gas, but that need lo import oil or oil products to meet their local demand, SMDS products manufactured in that country should realize at least, import parity values. In some cases these may be far above the normal world spot market values. For such countries therefore, the national benefit of the SMDS process may be substantial."
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We interrupt here to emphasize one statement in the immediately foregoing, and to urge you to consider it relative to the potentials for West Virginia, for the United States, to convert our abundant domestic reserves of Coal into liquid fuels: "For countries ... that need lo import oil ... SMDS products manufactured in that country should realize at least, import parity values ... (which might) be far above the normal ... market values (and) the national benefit of the SMDS process may (thus) be substantial."
Also, note that Fischer-Tropsch products are "free from nitrogen and sulphur".
In any case, whether or not the Bintulu facility is to use primarily Methane from offshore natural gas wells or from gasified lignite Coal, Shell does acknowledge Coal to be an important raw material for their MDS system to produce liquid hydrocarbons, in their patent application for that technology.
As evidenced by the following link and excerpt:
FUEL COMPOSITION - Patent application - middle distillate fuel composition is provided comprising a middle distillate base fu.
"Patent application title: Fuel Composition
Inventors: Feliz Balthasar and Karsten Wilbrand
Agents: Shell Oil Company; Houston, TX
(From deep within the patent description): The carbon monoxide and hydrogen may themselves be derived from organic or inorganic, natural or synthetic sources, typically either from natural gas or from organically derived methane, or from coal, oil sands, or shale oil deposits and similar sources. In general the gases which are converted into liquid fuel components using Fischer-Tropsch processes can include natural gas (methane), LPG (e.g. propane or butane), "condensates" such as ethane, synthesis gas (carbon monoxide/hydrogen) and gaseous products derived from coal, biomass and other hydrocarbons. The Fischer-Tropsch process can be used to prepare a range of hydrocarbon fuels, including LPG, naphtha, kerosene and gas oil fractions."
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As we have previously documented, the Shell Middle Distillate System is, in fact, an advancement on, a refinement of, the original Fischer-Tropsch technology for the conversion of Coal into liquid fuels that was, along with the Bergius Coal-to-Liquid conversion process, reduced to industrial practice at multiple sites in Europe and Asia, during WWII, to supply the armies of Germany and Japan with liquid fuels.
The sum of it all, the point, is: We can synthesize Methane via either the Sabatier recycling of Carbon Dioxide or the hydro-gasification of Coal.
Once we have the Methane, we can use Shell's MDS technology to convert it into Gasoline.