Major achievements by our United States Government in the profitable conversion of our abundant United States Coal into fuel alcohol Methanol and related products have been made, but have not, from our perspective, been fully and openly reported to the United States public.
We will do our best to correct some of those deficits in reports to follow, but remind you, that, as seen, for just two, out of many possible examples in our past reports of:
US Navy Coal + H2O = Low Cost Methanol | Research & Development | News; concerning: "United States :Patent 4,476,249 - Low Cost Method for Producing Methanol; 1984; Inventor: William Avery, MD; Assignee: The Johns Hopkins University, Baltimore; The Government has rights in this invention pursuant to Contract N00024-78-C5384 awarded by the Department of the Navy. Abstract: Method for producing low cost methanol. A source of carbon is provided to an OTEC plant or plantship which is processed to produce carbon monoxide which is reacted with hydrogen to produce methanol. The oxygen and hydrogen are obtained from the electrolysis of water with the required energy supplied by ocean thermal energy conversion (and) ... providing a source of carbon ... is accomplished by: the pyrolysis of coal"; and:
USDOE 1976 Atmospheric CO2 to Methanol | Research & Development | News; concerning: "United States Patent 3,959,094 - Electrolytic Synthesis of Methanol from CO2; 1976; Inventor: Meyer Steinberg, NY; Assignee: The USA as represented by the USDOE; Abstract: A method and system for synthesizing methanol from the CO2 in air using electric power. The CO2 is absorbed by a solution of KOH to form K2CO3 which is electrolyzed to produce methanol, a liquid hydrocarbon fuel";
various branches of our own government have for many decades known how to convert both Coal and, even as recovered from the atmosphere, Carbon Dioxide into Methanol.
As we've also documented many times, as for just one example in:
ExxonMobil "Coal to Clean Gasoline" | Research & Development | News; concerning: "'Coal to Clean Gasoline'; Xinjin Zhao, Ron D. McGihon and Samuel A. Tabak; ExxonMobil Research and Engineering Company, USA, discuss ExxonMobil's methanol to gasoline technology for the production of clean gasoline from coal. There are two commercially demonstrated routes for converting coal to transportation fuels through gasification. The widely known Fischer-Tropsch process was first discovered in the 1920s. It has been commercially practiced by Sasol in several different forms ... . ... Although it is less known, there is another commercially proven alternative for converting coal to gasoline, through methanol. ExxonMobil’s methanol-to-gasoline (MTG) process efficiently converts crude methanol to high quality clean gasoline. When coupled with commercially proven coal gasification and methanol synthesis technology, MTG offers an effective route to premium transportation fuel from coal";
Methanol, as made from Coal or Carbon Dioxide, can be efficiently and directly converted into Gasoline.
Note that the link we included in the above report to ExxonMobil's presentation of "Coal to Clean Gasoline" no longer functions in the version posted on the web by the West Virginia Coal Association. By way of correction, here's a fresh link that works at the time of this transmission:
Further, we're attaching a downloaded copy of the file.
Without referring to other past reports, we note that ExxonMobil's catalytic process for converting Methanol into Gasoline did suffer from some drawbacks. Primarily, it is a highly exothermic reaction, and the heat generated with the Gasoline has to be removed or the catalyst bed will be damaged and cease to function. As we've reported, that fact enables the co-production of some electricity, with the Gasoline, from the overall Coal-to-Methanol-to-Gasoline process. However, the design and construction of such a Methanol-to-Gasoline reactor, wherein the heat of reaction is harvested and extracted, does require much more capital. There is more expense involved, and, although that expense could be repaid via co-generation of electricity, such a scenario also requires more maintenance and entails the potential for down-time, etc.
To help correct those potential deficiencies, ExxonMobil have continued to improve the design of their Methanol-to-Gasoline, "MTG"(r), reaction process, and one result of their efforts in that regard, which actually leads to the production of Diesel Fuel as well as Gasoline from Coal-derived Methanol, is, as excerpted from the initial link in this dispatch, the very recent:
"US Patent 9,090,525 - Process and System to Convert Methanol to Light Olefin, Gasoline and Distillate
Process and system to convert methanol to light olefin, gasoline and distillate - EXXONMOBIL RESEARCH AND ENGINEERING COMPANY
Date: July 28, 2015
Inventor: Stephen Brown, NJ
Assignee: ExxonMobil Research And Engineering Company, NJ
Abstract: The present invention provides a process for forming a refined hydrocarbon that includes providing a feed including methanol, dimethyl ether or a mixture thereof, and contacting the feed with a methanol conversion catalyst under suitable conditions to yield an intermediate composition including olefins having at least two carbon atoms. The intermediate composition is introduced to an oligomerization catalyst under suitable conditions to yield gasoline boiling range components and distillate boiling range components.
Claims: A process for converting a feed comprising methanol to a hydrocarbon product, comprising:
(a) contacting the feed in a first, fixed bed adiabatic conversion reactor with a methanol conversion catalyst under suitable conditions to yield an intermediate composition including olefins having at least two carbon atoms;
(The "adiabatic" just means that no heat needs to be added or removed.)
(b) separating a liquid hydrocarbon phase comprising recycled gasoline boiling range components unreacted in the first reactor and methanol conversion products from the C2- gas and water in the intermediate composition;
(c) introducing the liquid hydrocarbon phase from separation step (b) to a second, separate conversion reactor containing an olefin oligomerization catalyst under suitable conditions to yield gasoline boiling range components and distillate boiling range components;
(d) separating the gasoline boiling range components and distillate boiling range components; and:
(e) recycling a portion of the separated gasoline boiling range components containing at least predominantly C5 to C12 hydrocarbons to the feed to be contacted with the methanol conversion catalyst in the first conversion reactor in an amount which constitutes from about 40 to about 90 weight percent of the total feed to the methanol conversion catalyst to control the adiabatic temperature arise in the first conversion reactor and convert C5+ olefins in the recycle stream to C5+ branched paraffins and C7+ aromatics.
The process ... wherein the methanol conversion catalyst converts from about 90 percent to about 95 percent of the methanol in the feed.
(The above claim represents a great improvement in the efficiency and productivity of the original MTG(r) process technology.)
The process ... wherein the separation of the C2- gas and water from the intermediate composition occurs in a three phase settler apparatus (and) wherein separating the gasoline boiling range components and distillate boiling range components includes fractionating the gasoline boiling range components and distillate boiling range components in at least one distillation column.
The process ... wherein the methanol conversion catalyst is selected from ZSM-5, ZSM-11, MCM-68 and ZSM-12 catalysts (and) wherein the olefin oligomerization catalyst is a selective dimerization catalyst selected from ZSM-5, ZSM-57, ZSM-22, ZSM-12, ZSM-48 and SAPO-11 catalysts.
(All of the specified catalysts are known, and are commercially available or can be made so.)
The process ... wherein the methanol conversion catalyst is maintained in a first vessel maintained at a temperature of from about 330 C to about 430 C and a pressure of about 15 psig to about 75 psig (and) wherein the olefin oligomerization catalyst is maintained in a second vessel maintained at a temperature of from about 200 C to about 300 C and a pressure of from about 750 psig to about 1500 psig.
The process ...in which the liquid hydrocarbon phase separated in step (b) comprises greater than 95 weight percent of the methanol conversion products from the first reactor.
The process ... in which the liquid hydrocarbon phase separated in step (b) is introduced into the second reactor with no compression.
Background and Field: The present invention relates to processes and systems that provide for the conversion of methanol and/or dimethylethers to light olefins, gasoline and/or distillate products.
(The "distillate products" would include Diesel fuel.)
Aluminosilicate zeolite and other catalysts have been employed to convert methanol and/or dimethylethers to hydrocarbons, such as methanol to gasoline (MTG processes). The productivity of methanol conversion processes is limited primarily by the limits of the catalyst itself, which deactivates upon continued service due to, for example, the presence of steam, which in turn causes dealumination of the zeolite. The steaming conditions are inherent to a methanol and/or dimethylether conversion process and depend upon the total amount of methanol or oxygenate processed during the catalyst life, since one mole of water is generated for every mole of methanol or dimethylether converted.
MTG processes can generally yield, for example, between only 0.2 and 2 g hydrocarbon per g catalyst hour. As a result, catalyst costs are high.
Heat management is also a capital intensive endeavor, which is especially true in methanol conversion processes, such as MTG processes. Often, there is a need for large amounts of recycle solely to control heat, as the reaction from methanol to gasoline and distillate is highly exothermic. It is desirable to reduce the heat release in the first reaction stages in a MTG process.
In order to provide a methanol to gasoline process with increased economic feasibility, there is a need to improve the output of catalysts and to better manage the heat produced during the process in order to reduce heat recycle requirements.
Summary: The efficiency of a methanol to gasoline and distillate process is improved by selectively oligomerizing some, if not most, of the C5- light olefins produced in a first methanol conversion reaction to a mixture of gasoline and distillate boiling range components in a second, integrated reactor. Moving light olefin oligomerization into a second reactor cuts the heat release in the first reactor significantly (e.g., by over 50%) and also improves catalyst output. As a result, inexpensive fixed bed adiabatic reactors can be used without large amounts of recycle to control heat. The second reaction can be conducted using proven, tubular reactor technology with no recycle streams.
Accordingly, one aspect of the present invention provides a process for forming a refined hydrocarbon that includes providing a feed including methanol, dimethyl ether or a mixture thereof, and contacting the feed with a methanol conversion catalyst under suitable conditions to yield an intermediate composition including olefins having at least two carbon atoms. The intermediate composition is introduced to an oligomerization catalyst under suitable conditions to yield gasoline boiling range components and distillate boiling range components. The process also includes separating the gasoline boiling range components and distillate boiling range components.
Examples of distillates or distillate boiling range components include, but are not limited to, naphtha, jet fuel, diesel, kerosene, aviation gas, fuel oil, heating oil and blends thereof".
So, we now have the technology in hand to, at a lower cost and with more productivity than before, convert Methanol, at a rate of "90 percent to about 95 percent" single pass efficiency, which is pretty darned good, into Gasoline and into "jet fuel, diesel, (etc.) and blends thereof"; which products, if you read the full Disclosure carefully, after separation require, according to ExxonMobil, very little further refining to be ready for commercial distribution and use. This is an efficient and clean process.
And, to again remind you, as seen in our reports of:
Pennsylvania Converts More Coal to Methanol | Research & Development | News; concerning: "United States Patent 5,284,878 - Liquid Phase Methanol Process with CO-rich Recycle; 1994; Inventor: David Studer and Elizabeth Schaub, PA; Assignee: Air Products and Chemicals, Incorporated, Allentown; Abstract: Methanol is produced by reacting a CO-rich synthesis gas in the presence of a powdered methanol synthesis catalyst suspended in an inert liquid in a liquid phase reactor system. Unreacted CO-rich synthesis gas is recycled to the reactor, thus increasing methanol production and reducing specific power compared with once-through operation without recycle or compared with recycle of hydrogen-rich gas recovered from unreacted synthesis gas. The process preferably is integrated with a coal gasification electric power generation system in which a portion of the unreacted synthesis gas is used as power generation fuel and a portion of the methanol product is used as additional power generation fuel during periods of peak power demand"; and:
California July 2012 Efficient CO2 to Methanol | Research & Development | News; concerning: "United States Patent 8,212,088 - Efficient and Selective Chemical Recycling of Carbon Dioxide to Methanol, Dimethyl Ether and Derived Products; 2012; Inventors: George Olah and G.K. Surya Prakash, CA; Assignee: University of Southern California, Los Angeles;Abstract: An efficient and environmentally beneficial method of recycling and producing methanol from varied sources of carbon dioxide including flue gases of fossil fuel burning powerplants, industrial exhaust gases or the atmosphere itself. Converting carbon dioxide by chemical or electrochemical reduction secondary treatment to produce essentially methanol, dimethyl ether and derived products";
we're getting pretty darned good at converting our abundant United States Coal and our some-say too abundant Carbon Dioxide into Methanol, which can then, via the process of our subject herein, ExxonMobil's "United States Patent 9,090,525 - Process and System to Convert Methanol to Light Olefin, Gasoline and Distillate", be efficiently and pretty completely converted into all-American and non-OPEC Gasoline and Diesel, and other products like "jet fuel", which, again if we read the patent documents correctly, require very little further refining, after separation, before distribution and use in their intended markets.