Re: GAS-L: Re: LPG and steam reforming

[Peter Singfield <snkm@btl.net>]

Taking this out of the stove list domain!

For those out there that are serious and can delve through technical
presentations -- interested in steam reforming??

Start here:

US patent 5,763,716 

go to this site:

http://patft.uspto.gov/

Enter the above number into the search slot.

Have appended some "snips" -- but the "Description" part gives an entire
history of this "industry" and is extremely detailed. Also to huge to post.

The basis of high efficiency steam reforming is all about keeping the
proper ratios of "pure" H2 and CO.

And this is the major cost and problem involved in steam reformation of
synthesis gas to preferred product.

Come up with a simple way to do this -- and bingo -- no need for the mega
processing plant.

Again -- this can be accomplished by using a molten tin bath -- not covered
in this reference.

I can supply complete info on that process -- but better let brains rest --
quite a chew right here.

bottom line:

OK -- the India micro factories for sugar production work for these reasons.

#1: Capital cost payback is less than $10 per ton of sugar produced -- not
$375! At the "real" interest rates of 15%!!

#2: Extremely low transportation costs -- in forwarding biomass to plant --
as a plant requires just one hundred acres of cane. Can be done by
"hand-cart" (oh my -- look at all the modern workers faint right there!!)

#3: Extraction efficiency of 14% -- much better than the normal 10%

The disadvantage is grueling manual labor for low pay. No problem for us in
3rd world -- but impossible for 1'st world "workers".

Now -- this same plant operation example can be applied to generating
"fuel" from biomass from small "utilities".

Don't think so??

OK -- how about producing 80 liters of ethanol per ton of cane for a
portable fuel -- and burning the bagasse in a reliable fire tube boiler --
but instead of boiling water -- use a thermal oil -- and feed that to an
Ormat turbine. 

Gentlemen -- I have the quotes in hand from Ormat and the from Skip
(remember him oh ye gas listers) now of Apin boilers in Peru.

You would never believe the prices!!

And no need for the sugar making part -- which cuts the cost of the micro
plant down a further large chunk!

Anywhere sugar cane can be grown -- people should not have to suffer for
lack of fuel or food!

Course -- not much work for the Phd's in these kind of ventures -- and that
kills it -- right??

Plus -- hard to grow sugar cane in the industrialized nations -- to cold.

Also -- ethanol "stoves" need no further improvements -- so there goes the
new wave stick burners.

Brazil used "strong rum" (not pure ethanol) to move its vehicles around for
almost one century -- so prior art is well established.

No fossil fuel mega giant corp to fund salaries for 100's of qualified
"modern" nation technical "experts" to guide the way -- eh??

My message to 3rd world -- stay away from these "free" rides -- they take
you down the wrong roads -- and all ends up lost.

I can put together the "same" for a small/micro gas plant -- any day -- any
time!!

No way to wake you guys up -- is there??

OK -- I have done my "shaking" of this tree -- off to real world --

Again -- for those interested -- check that patent!

Dust off the brain cells -- make them do something for a change -- OK???

Better now -- than after your bubble has burst -- then it is to late.

I find the lack of true innovation in visualizing real world energy
solutions astounding!

Well -- at least the list is no longer promoting 3rd world adopting WWII
gasifier technology as the solution to fueling motive apparatus.

But how many years did that take to "discourage"??

Is there some mysterious "chemical" introduced to people living in modern
industrialized nations making them all brain dead!!

Come on people -- "think" -- it is like swimming -- once done -- never
forgotten.

And for those brain stalled Phd's out there -- do not try to beat me on the
head with yourr diploma -- I'll bury you in hard -- real -- DATA! 

I'll question on what basis you earned that piece of paper! Intellectual
snobbery is not a viable solution to an ever growing energy shortage in
"poor" 3rd world!

We can't just go out and "take" any oil producing nation to secure future
oil supplies like some countries can!

We will feel the real crunch long before the Robber Baron nations do!

While you all play -- we try to survive.

Pompous statements in regards ot what is impossible by "modern" world
standards -- surely -- we can do better than this??

In fact -- we "MUST" -- granted -- people in industrialized nations are
better brain dead -- cows in their barn are not advised to "think" -- are
they? Just grab that check from the trough -- better the diploma -- better
the check -- real world -- real time -- performance -- be damned!!

Your bubble is rapidly increasing beyond the size surface tension can hold
it together -- 

"Think" or be damned!

Peter/Belize

*********************
Claims

----------------------------------------------------------------------------
----


What is claimed is: 

1. The process for the conversion of a hydrocarbon gas stream into products
including liquid hydrocarbons comprising the steps of: 

first, catalytically reacting the hydrocarbon gas in a first reaction zone
in the presence of water and sufficient carbon dioxide to produce hydrogen
and carbon monoxide product in a ratio of hydrogen to carbon monoxide of
from about 0.5 to about 2.0 to 1 and then removing carbon dioxide from the
hydrogen and carbon monoxide produced in this step and recycling at least a
portion of this carbon dioxide back to the first reaction zone; 

second, catalytically reacting the hydrogen and carbon monoxide having a
reduced carbon dioxide content in a second reaction zone in the presence of
a slurry containing an alkali promoted iron-based catalyst under conditions
favoring the formation of carbon dioxide, light hydrocarbon gases, and
normally liquid hydrocarbons containing at least five carbon atoms, and
hydrocarbon waxes, and then separating the liquid hydrocarbon products from
the gaseous products; and 

third, reacting the gaseous products in a third reaction zone in the
presence of a slurry containing an alkali promoted iron-based catalyst to
produce additional liquid hydrocarbon product. 

2. The process of claim 1 wherein the ratio of carbon from the hydrocarbon
gases first reacted to carbon dioxide is one part of carbon from
hydrocarbon gas to up to two parts of carbon dioxide. 

3. The process of claim 2 wherein the ratio of carbon from hydrocarbon gas
to carbon dioxide and water is one part of carbon from the hydrocarbon gas
to four parts of carbon dioxide and water. 



----------------------------------------------------------------------------
----

 Description

----------------------------------------------------------------------------
----


BACKGROUND OF THE INVENTION 

This invention relates to a method and a system for the production of
hydrocarbons and hydrocarbon compounds which includes the use of a
Fischer-Tropsch synthesis reactor and process, utilizing a promoted
iron-based catalyst, in combination with processes for converting
hydrocarbon-containing gases in general, and in particular, methane rich
gases, into hydrogen and carbon monoxide from such gases. 

Considerable research and development work has been undertaken in the past
to commercially apply the Fischer-Tropsch synthesis of hydrocarbons,
starting from a wide variety of carbonaceous and hydrocarbon starting
materials. 

A compendium of some of the prior work with Fischer-Tropsch synthesis
technology is contained in the Bureau of Mines Bulletin 544 (1955) entitled
Bibliography of the Fischer-Tropsch Synthesis and Related Processes by H.
C. Anderson, J. L. Wiley and A. Newell. 

The product distribution and yields from specific Fisher-Tropsch reactions
with iron catalysts have also been examined by Charles N. Satterfield and
George A. Huff, Jr. in an article entitled Carbon Number Distribution of
Fischer-Tropsch Products Formed on an Iron Catalyst in a Slurry Reactor,
Journal of Catalysis 73, 187-197 (1982), wherein the Shultz-Flory
distribution is examined with respect to various catalyst systems. 

In addition, the article entitled Fischer-Tropsch Processes Investigated at
the Pittsburgh Energy Technology Center Since 1944 by Baird, Schehl, and
Haynes in Industrial and Engineering Chemistry, Product Research and
Development, 1980, 19, pages 175-191, describes various Fischer-Tropsch
reactor configurations. 

The foregoing articles describe in considerable detail how specific
catalysts can be employed in various reaction vessel configurations under
conditions which favor the conversion of carbon monoxide and hydrogen into
specific product groups. 

There have only been a few instances wherein the Fischer-Tropsch reaction
has been incorporated into a complete system, starting with a solid or
gaseous feed stock. Germany placed several plants in operation during the
1930's and 1940's using coal as the feed stock, referenced in Twenty-Five
Years of Synthesis of Gasoline by Catalytic Conversion of Carbon Monoxide
and Hydrogen, Helmut Pichler, Advances in Catalysis, 1952, Vol. 4, pp.
272-341. In addition to the foregoing, South Africa has been using
Fischer-Tropsch technology based upon this German work for the past 35
years to produce gasoline and a variety of other products from coal,
referenced in Sasol Upgrades Synfuels with Refining Technology, J. S.
Swart, G. J. Czajkowski, and R. E. Conser, Oil & Gas Journal, Aug. 31,
1991, TECHNOLOGY. There was also a Fischer-Tropsch plant built in the late
1940's to convert natural gas to gasoline and diesel fuel described in
Carthage Hydrocol Project by G. Weber, Oil Gas Journal, 1949, Vol. 47, No.
47, pp. 248-250. These early efforts confirmed that commercial application
of the Fischer-Tropsch process for the synthesis of hydrocarbons from a
hydrocarbon-containing feed stock gas requires solving, in an economical
manner, a set of complex problems associated with the complete system. For
example, initially, it is important for the hydrocarbon-containing feed
stock to be converted into a mixture consisting essentially of hydrogen and
carbon monoxide before introduction of the mixture into the Fischer-Tropsch
reactor. Economic operation of specific sizes of Fischer-Tropsch reactors,
generally requires the ratio of hydrogen to carbon monoxide to be within
well established ranges. The Hydrocol plant, referenced hereinbefore, used
partial oxidation of natural gas to achieve a hydrogen to carbon monoxide
ratio of about 2.0. An alternative approach to partial oxidation uses steam
reforming for converting light hydrocarbon-containing gases into a mixture
of hydrogen and carbon monoxide. In this latter case, steam and carbon
dioxide, methane and water are employed as feed stocks and carbon dioxide
can be recycled from the output of the reformer back to its inlet for the
purpose of reducing the resultant hydrogen to carbon monoxide ratio. 

There are therefore, two primary methods for producing synthesis gas from
methane: steam reforming and partial oxidation. 

Steam reforming of methane takes place according to the following reaction: 

H.sub.2 O+CH.sub.4 .apprxeq.3H.sub.2 +CO (1) 

Since both steam and carbon monoxide are present, the water gas shift
reaction also takes place: 

H.sub.2 O+CO.apprxeq.H.sub.2 +CO.sub.2 ( 2) 

Both of these reactions are reversible, i.e., the extent to which they
proceed as written depends upon the conditions of temperature and pressure
employed. High temperature and low pressure favor the production of
synthesis gas. 

Partial oxidation reactions utilize a limited amount of oxygen with
hydrocarbon-containing gases, such as methane, to produce hydrogen and
carbon monoxide, as shown in equation (3), instead of water and carbon
dioxide in the case of complete oxidation. 

1/2 O.sub.2 +CH.sub.4 .fwdarw.2H.sub.2 +CO (3) 

In actuality, this reaction is difficult to carry out as written. There
will always be some production of water and carbon dioxide; therefore the
water gas shift reaction (2) will also take place. As in the steam
reforming case, relatively high temperatures and relatively low pressures
favor production of synthesis gas. 

The primary advantage of partial oxidation over steam reforming is that
once the reactants have been preheated, the reaction is self-sustaining
without the need for the addition of heat. 

Another advantage of partial oxidation is the lower ratios of hydrogen to
carbon monoxide normally produced in the synthesis gas which ratios better
match the desired ratio for use in the Fischer-Tropsch synthesis of
hydrocarbon liquids in the overall process. 

A still further advantage of partial oxidation resides in the elimination
of a need for the removal of carbon dioxide and/or hydrogen from the
synthesis gas before being fed to the synthesis reactors. 

While adjustment of the hydrogen to carbon monoxide ratio can be achieved
by removal of excess hydrogen using a membrane separator, for example. This
approach requires additional capital equipment and can result in lower oil
or liquid hyrdrocarbon yields due to a loss of hydrogen to the process. 

In order for the overall process considerations to be used in a manner
which can produce economical results whether employing either steam
reforming or partial oxidation of a feed stock, the Fischer-Tropsch reactor
must typically be able to convert at least 90% of the incoming carbon
monoxide. If a 90% conversion efficiency is to be achieved in single pass
operation and hydrogen is not removed before introduction of the gas stream
into the reactor, the build up of unreacted hydrogen due to the excess of
hydrogen will necessitate a larger reaction vessel to maintain a
sufficiently long residence time in the reaction vessel. Recycle of
unreacted hydrogen and carbon monoxide from the outlet of the
Fischer-Tropsch reactor back to its inlet is commonly employed to achieve
the required conversion. However, when an excess of hydrogen is employed,
an even greater excess of unreacted hydrogen will build up under such a
recycle operation. This condition, in turn, can necessitate an even larger
reaction vessel or alternatively the hydrogen removal described must be
employed. 

Major drawbacks to the commercialization of many of the prior processes
were the high cost of product specific catalysts, and when an inexpensive
catalyst was utilized an unacceptable overall process conversion efficiency
of the carbon input into the hydrocarbon products produced. 

***********snipped --- huge amount left*************

And all kinds of charts -- as example:

***************

While the contribution of the presence of alcohols to the superior
performance of the F/T diesel with respect to emissions generally and
particulate airborne emissions more specifically is not fully understood at
the present time, the following analysis clearly shows the superior
performance of the F/T diesel fuel of the present invention. 


                  TABLE III
    ______________________________________
    SYNTHETIC DIESEL FUEL
    ______________________________________
    ASTM Distillation, .degree.F.
    IBP                      332
    90%                      514
    EP                       555
    Cetane Index             62
    Sulfur Content, wt %     <.001
    Cloud Point, .degree.F.  -2
    Pour Point, .degree.F.   -6
    Conradson Carbon on 10% Residuum, wt %
                             .05
    Flash Point, .degree.F.  146
    Bottom Sediment & Water, vol. %
                             <.025
    Kinematic Viscosity @ 100 .degree.F., cSt
                             1.89
    API Gravity @ 60.degree.F.
                             48.5
    Aromatics, wt %          less than 1%
    Paraffins, wt %          47
    Olefins, wt %            41
    Alcohols, wt %           6
    Other oxygenates, wt %   6
    Heat of Combustion, Btu/lb
                             18,585
    Heat of Combustion, Btu/gal
                             128,230
    ______________________________________
              TABLE IV
    ______________________________________
    EMISSION RESULTS
    (g/bhp-hr)
                 HC  CO         NOx    BSP
    ______________________________________
    #1 DIESEL FUEL .81   1.25       4.89 .326
    std. dev.      .01   .02        .02  .001
    SYNTHETIC FUEL .69   1.08       5.19 .268
    std. dev.      .01   .00        .02  .008
    ______________________________________

******************

EXAMPLE 2 

Referring to FIG. 3 one million standard cubic feet (28,316 .mu.M.sup.3)
per day of natural gas (assumed to be methane regulated to a pressure of
230 psia (1590 kPa)) is heated to 700.degree. F. (371.degree. C.) in
preheater PH1 (not shown) and flows through sulfur removal bed S1 at a
space velocity of 700 M.sup.3 per hour per M.sup.3 of catalyst. S1 is a
fixed bed of commercially available zinc oxide spherical pellets ranging in
diameter from 1/8 inch (3 mm) to 3/16 inch (5 mm). This type of sulfur
removal process is appropriate for low levels of sulfur compounds, e.g.
less than 25 parts per million (ppm). 

The natural gas leaving S1 has a sulfur content less than 0.5 ppm and is
mixed with 1.46 MMSCF (41,343 M.sup.3) per day of carbon dioxide recycled
from stripper ST1 and 1.73 MMSCF (48,987 M.sup.3 per day of steam. The
mixture is preheated to 1292.degree. F. (700.degree. C.) in a preheater
(not shown) by the gases leaving the reforming reactor R1. The heated gas
mixture undergoes chemical reaction in the catalytic reforming reactor R1.
The catalyst is a commercial reforming catalyst such as nickel supported on
aluminum oxide in the form of raschig rings (e.g. catalyst 23-1 available
from Katalco). Since the chemical reactions taking place involving the
methane, steam and carbon dioxide are endothermic, heat is supplied to the
outside walls of the tubes containing the catalyst rings. Due to heat
transfer limitations, tube diameters are kept small, e.g. 5 inches (12.7)
cm) and several tubes are manifolded together. For the flow rates of this
example, a total of 12 tubes of 5 inches (17.7 cm) inside diameter and 24
feet (7.3 m) long would be required. 

The objective of the reforming reactor is to produce as much synthesis gas
(a mixture of hydrocarbon and carbon monoxide) and particularly carbon
monoxide as possible. The extent to which the carbon in the methane and
carbon dioxide is converted to carbon contained in carbon monoxide is
determined by the thermodynamic equilibrium of the water gas shift reaction: 

H.sub.2 +CO.sub.2 .apprxeq.H.sub.2 O+CO (11) 

and the steam-methane reaction: 

H.sub.2 O+CH.sub.4 .apprxeq.3H.sub.2 +CO (12) 

The equilibrium constants for these reactions depend on the temperature of
the gases leaving the reformer. Since reaction (12) involves an increase in
moles as the reaction consumes methane, higher pressures adversely affect
the extent of conversion of methane. The water-gas shift reaction readily
achieves equilibrium on the nickel catalyst whereas the steam-methane
reaction approaches to within about 16.degree. C. (29.degree. F.) of
equilibrium, and the projected results are based on this phenomenon. For
the present example with an exit gas temperature of 850.degree. C.
(1562.degree. F.) and a pressure of 225 psia (1550 kPa) the gas leaving the
reformer is comprised of 2.15 MMSCFD (60,879 m.sup.3 /day) of hydrogen,
1.52 MMSCFD (43,040 m.sup.3 /day) of carbon monoxide, 0.80 MMSCFD (22,653
m.sup.3 /day) carbon dioxide, 0.08 MMSCFD (2265 m.sup.3 /day) of methane
and 1.29 MMSCFD (36,528 m.sup.3 /day) of water. 



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