Method of preventing defluidization of carbonaceous particles

Fresh carbonaceous particles are introduced into a fluid-bed reaction zone containing a bed of non-agglomerating particles at an injection velocity in excess of about 200 ft/sec with the fresh particles having been preheated to a temperature within the plastic transformation range of the particles and introduced rapidly and directly into said bed of non-agglomerating particles. The reaction zone may be a hydrocarbonization zone, a carbonization zone, a gasification zone or any other fluid-bed reaction zone in which defluidization may be caused by undue agglomeration of the feed particles. A fluidized stream of the preheated carbonaceous particles may be introduced at said high injection velocity in a vertically upwards direction or otherwise, as from one or more injection points positioned vertically along the side of the reaction zone.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a method of avoiding excessive agglomeration of 
carbonaceous solid particles so as to prevent defluidization in a 
fluid-bed reaction zone. More particularly, it is an improved method for 
injecting fresh carbonaceous particles into a fluid-bed 
hydrocarbonization, gasification or carbonization reaction zone. 
2. Description of the Prior Art 
Increasing energy needs have focused attention on solid fossil fuels due to 
their availability in the United States in a relatively abundant supply 
and their potential value if converted into more useful forms of energy 
and feedstock. Processes such as carbonization, gasification, 
hydrocarbonization and hydrogasification, wherein synthetic fuel products 
have been prepared by introducing a fluidized stream of finely-divided 
coal or other solid carbonaceous particles into a fluid-bed reaction zone 
and reacting the said particles at elevated temperatures in the presence 
of air, steam, hydrogen or inert gases are well known. A major operating 
difficulty in such processes has been the tendency of coal or other 
carbonaceous particles, especially intensified in a hydrogen-rich 
atmosphere, to agglomerate at the elevated temperature required for 
reaction. 
Coal particles, especially caking, swelling or agglomerating coals, become 
sticky when heated in a hydrogen-rich atmosphere. Even non-caking, 
non-swelling and non-agglomerating coals become sticky when heated in such 
an atmosphere. Coal particles begin to become sticky at temperatures in 
the range of from about 280.degree. C., commonly from about 350.degree. C. 
to about 500.degree. C., depending on the specific properties of the coal, 
the atmosphere and the rate of heating. Such stickiness is due to a tarry 
or plastic-like material forming at or near the surface of each coal 
particle, by a partial melting or decomposition process. On further 
heating over a period of time, the tarry or plastic-like material is 
further transformed into volatile products and a substantially porous, 
solid material referred to as a "char." The length of this time period 
depends upon the actual temperature of heating and is shorter with an 
increase in temperature. The term "plastic transformation" as used herein 
refers to such tendency of the surfaces of coal or other carbonaceous 
particles being heated, particularly when heated in a hydrogen atmosphere, 
to develop stickiness and transform into substantially solid char, 
non-sticky surfaces. "Plastic transformation" is undergone by both 
normally agglomerating coals and coals which may develop a sticky surface 
only in a hydrogen-rich atmosphere. 
Agglomerating or caking coals partially soften and become sticky when 
heated to temperatures between about 280.degree. C., commonly from about 
350.degree. C., to about 500.degree. C. The duration of stickiness depends 
on the temperature of the coal, being on the order of minutes at the lower 
end of said range and being exponentially shorter, i.e. down to seconds, 
at the upper limits of said range. Components of the coal particles soften 
and gas evolves because of decomposition. Sticky coal particles undergoing 
plastic transformation tend to adhere to most surfaces which they contact 
such as walls or baffles in the reactor, particularly relatively cool 
walls or baffles. Moreover, contact with other sticky particles while 
undergoing plastic transformation results in gross particle growth through 
adherence of sticky particles to one another. The formation and growth of 
these agglomerates interferes drastically with the maintenance of a 
fluid-bed and excessive growth can make it impossible to maintain 
fluidization. 
In particular, entrance ports and gas distribution plates of equipment used 
in fluid-bed coal conversion processes become plugged or partially 
plugged. Furthermore, even if plugging is not extensive, the sticky 
particles tend to adhere to the walls of the reaction vessel, with 
continued gross particle growth and the formation of multi-particle 
conglomerates and bridges interfering with smooth operation and frequently 
resulting in complete stoppage of operation as a result of defluidization 
of the bed. 
Agglomeration of coal particles upon heating depends on operating 
conditions such as the heating rate, final temperature attained, ambient 
gas composition, coal type, particle size and total pressure. Even 
non-agglomerating coals, such as lignites or coals from certain 
sub-bituminous seams, are susceptible to agglomeration and tend to become 
sticky when heated in a hydrogen atmosphere. Thus, agglomeration of coal 
particles is accentuated in a hydrocarbonization reactor where heating in 
the presence of a hydrogen-rich gas actually promotes formation of a 
sticky surface on the coal particles reacted. Introducing any 
carbonaceous, combustible, solid particles, even those normally 
non-agglomerating, to a fluid-bed having an atmosphere tending to induce 
agglomeration can, moreover, result in agglomeration and defluidization of 
the bed. 
Heavy liquid materials are also fed at times to the fluid-bed in coal 
conversion processes. They may be recycled heavy tar products to be 
converted to lower molecular weight products, light liquids and gases. Or 
they may be heavy liquids added from an external source to, for example, 
enrich the normal gas and/or liquid product, or as a means of waste 
disposal. Feeding such liquids is known to cause rapid loss of 
fluidization due to excessive particle agglomeration and plugging. 
In an attempt to overcome the problems associated with agglomeration, char 
as a recycle material from fluidized bed processes has been mixed with an 
agglomerating type coal feed at a ratio as high as 8 to 1. Also, tar has 
been ball-milled with a great excess of absorbent char before feeding into 
a fluid-bed reaction zone. Such procedures reduce the unit throughput, are 
wasteful of energy and are, therefore, costly. Other attempts have 
included a pretreatment step wherein coal is oxidized and/or devolatilized 
superficially in order to prevent sticking and agglomeration of particles, 
but this lowers the yield of useful products and adds to the overall cost 
of the operation. Thus, it is highly desirable economically to avoid or at 
least reduce the extent to which such oxidation pretreatment or such char 
recycle is employed. 
An alternate approach is that suggested by Knudsen et al, U.S. Pat. No. 
3,927,996, in which the fines carried overhead by gas from a fluid-bed are 
monitored and the injection velocity of fresh feed material is regulated 
in response to changes in the fines content of the gas to produce 
controlled attrition of agglomerated particles in the fluid-bed. In this 
approach, a caking coal or other similar carbonaceous solid is introduced 
into a fluidized bed containing char particles maintained at a temperature 
in excess of the coal resolidification point by entraining coal particles 
in a gas stream preheated to a temperature in excess of about 300.degree. 
F., i.e. about 150.degree. C., but below the initial softening point of 
the coal. For the gasification of bituminous coals, preheat temperatures 
up to about 550.degree. F., i.e. about 285.degree. C., are said to be 
preferred. A fluid-cooled nozzle 16 is employed for feeding the stream of 
carrier gas and entrained coal particles into the gasifier zone. The 
injection velocity is regulated between superficial gas velocities as low 
as 15 feet/second and as high as 1,000 feet/second in response to 
variations in the fines content of the overhead gas. Such a system 
necessarily requires continual processing adjustments that are not 
desirable in continuous, commercial scale operations. In addition, the 
intermittent high injection velocities of the fresh coal introduced into 
the fluid-bed under the indicated conditions would generally be considered 
as having a potential for injection nozzle erosion that, if severe, could 
lead to a need for premature shutdown for nozzle replacement, adversely 
affecting the overall effectiveness of the coal conversion operation being 
carried out in the fluid-bed reaction zone. 
A need thus exists in the art for improved methods for treating 
agglomerating coal or other solid carbonaceous particles in fluid-bed 
reaction zones. This need resides with respect to the effective injection 
of fresh particles of such coal or other carbonaceous materials under 
conveniently controlable conditions capable of avoiding excessive 
agglomeration of feed particles and thus preventing defluidization of the 
bed. Such improved methods would desirably avoid the necessity for 
pretreatment oxidation of the feed particles and/or their admixture with 
recycle char particles prior to being introduced into the fluid-bed 
reaction zone. The improvements required for technically and economically 
feasible coal injection operations must not, on the other hand, introduce 
peripheral processing disadvantages, such as undue injection nozzle wear, 
that would adversely affect the overall coal or other solid carbonaceous 
particle conversion operation. 
It is an object of the invention, therefore, to provide a method of 
preventing excessive agglomeration of carbonaceous feed material in 
fluid-bed conversion operations. 
It is another object of the invention to provide a method of avoiding 
defluidization in fluid-bed reaction zones employed in coal or other solid 
carbonaceous conversion operations. 
It is another object of the invention to provide a method for employing 
caking coals on a continuous basis in a continuous fluid-bed reaction zone 
without defluidization and/or undue equipment plugging problems. 
It is a further object of the invention to provide a method for avoiding 
excessive feed particle agglomeration while, at the same time, avoiding 
undue injection nozzle erosion. 
It is a further object of the invention to provide improvements in the 
hydrocarbonization process for the preparation of fuel products from coal. 
With these and other objects in mind, the invention is hereinafter 
described in detail, the novel features thereof being particularly pointed 
out in the appended claims. 
SUMMARY OF THE INVENTION 
Fresh coal or other solid carbonaceous particles are preheated to a 
temperature within the plastic transformation temperature range of the 
particles an are injected rapidly and directly into a fluid-bed of 
non-agglomerating particles at an injection velocity in excess of about 
200 ft/sec. Nozzle erosion is thereby minimized without, at the same time, 
causing undue agglomeration of the fresh feed particles.

DETAILED DESCRIPTION OF THE INVENTION 
The objects of the invention are accomplished by injecting solid 
carbonaceous feed particles to a fluid-bed reaction zone at high injection 
velocities and at preheat temperatures within the plastic transformation 
range of the particles. Upon being preheated to said range, the particles 
are thus rapidly and directly injected into the reaction zone containing a 
fluidized bed of non-agglomerating particles. As described above, the 
particles form a tarry or plastic-like material at or near the surface of 
the individual particles upon being heated to a temperature within their 
plastic transformation temperature range. Particles are not preheated to 
said range in conventional operations because the stickiness resulting 
from such formation of a plastic-like material causes undesired 
agglomeration and the possibility of plugging the entrance ports and gas 
distribution plates of the equipment, adherence of the sticky particles to 
the walls of the reaction vessel with the formation of multi-particle 
conglomerates and bridges interfering with the operation of the bed, and 
eventual defluidization or bed failure as a result of excessive 
agglomeration. 
It has now been found, surprisingly and contrary to the conventional wisdom 
of the art, that feed particles may be preheated to a temperature within 
the plastic transformation temperature range and, at said preheat 
temperature, rapidly and directly injected into the fluid-bed of 
non-agglomerating particles at a high injection velocity without excessive 
agglomeration and resultant defluidization. The lubricity of the thus 
preheated fresh feed particles, in addition, has been found to minimize 
nozzle erosion that might be expected at high injection velocities. The 
high velocity injection of the preheated particles into the reaction zone 
achieves the desired rapid and uniform dispersion of the feed particles 
within the fluid-bed of non-agglomerating particles before the stickiness 
of the particles can result in undue agglomeration. The lubricity of the 
particles nevertheless results from the formation of said plastic-like 
material at the particle surface, thereby permitting the high speed 
injection of the fresh carbonaceous feed material in a carrier gas with 
little or no erosion of the injection nozzle. As the injection method of 
the invention obviates the need for admixture of the fresh feed with 
recycle char to avoid agglomeration, fresh feed injection without recycle 
char avoids the abrasiveness of the char at high injection velocities and 
avoids the nozzle erosion that results when a fresh feed-recycle char 
mixture is injected into the fluid-bed. The invention, therefore, achieves 
the highly desirable result of avoiding excessive agglomeration leading to 
defluidization of the bed while, at the same time, minimizing nozzle 
erosion that would otherwise cause a premature shutdown of the fluid-bed 
operations for nozzle replacement purposes. 
The invention can be employed in the practice of any known fluid-bed coal 
conversion process in which defluidization and bed failure due to 
excessive agglomeration may seriously interfere with, or even prevent, 
effective utilization of such technology on a continuous, commercially 
feasible basis. One such process is the hydrocarbonization process in 
which the gaseous reagent for fluidizing the bed and for reaction with 
fresh solid carbonaceous particles at reaction temperatures of from about 
450.degree. C. to about 750.degree. C., preferably from about 500.degree. 
C., to about 600.degree. C., is a hydrogen-rich, oxygen-free gas. Another 
such process is the carbonization process in which the reagent comprises 
carbonization product gases and vapors and essentially inert carrier gas 
at reaction temperatures of from about 450.degree. C. to about 700.degree. 
C. A third such process is the gasification process in which solid 
carbonaceous particles are reacted with steam to form synthesis gas at 
temperatures generally from about 815.degree. C. to about 1,100.degree. C. 
It will be appreciated by those skilled in the art that the invention may 
advantageously be employed in the practice of other such known processes 
or those subsequently developed so as to avoid excessive agglomeration 
upon the feeding of fresh carbonaceous solids to a fluid-bed reaction 
zone. 
The fluid-bed reaction zone is conventionally maintained by passing 
fluidizing medium through finely-divided solid particles. "Introduction 
velocity" as used throughout the specification means the superficial 
velocity of carrying gas. By a high velocity is meant a velocity 
sufficient to rapidly and uniformly disperse fresh coal particles entering 
the fluid-bed at a temperature below the plastic transformation 
temperature within a matrix of non-agglomerating particles in the 
fluid-bed. The non-agglomerating particles contained in the fluid-bed may 
include inert materials such as ash, sand, recycled char and the like 
which are inherently non-agglomerating. The non-agglomerating particles 
are, however, preferably hot, partially reacted coal particles and char 
particles that have undergone plastic transformation and are situated 
within the fluid-bed reaction zone at the reaction temperature, e.g. 
generally above about 450.degree. C. Due to the difference of temperature 
between the entering coal particles and the reaction zone, heat is 
ordinarily transferred rapidly from the reaction zone to the entering coal 
particles, accelerating the plastic transformation process increasing the 
agglomerating tendency of the feed coal for a brief period of time. It has 
been found that when the preheated coal is rapidly introduced in the 
fluid-bed at a high velocity, however, the entering coal particles rapidly 
and uniformly disperse within a matrix of non-agglomerating particles 
within the fluid-bed without excessive particle agglomeration. 
Introduction of coal particles into the fluid-bed at a high velocity as 
described hereinabove, promotes rapid, turbulent mixing of the entering 
particles with the particles circulating in the fluid-bed. This prevents 
their coherence and defluidization of the bed by imparting sufficient 
mechanical energy to the reaction zone to break the weaker bonds of the 
coarser agglomerates, thereby limiting the extent of agglomeration and 
substantially avoiding defluidization resulting from excessive 
agglomeration. The entering, sticky or potentially sticky coal particles 
are rapidly distributed with and brought into intimate association with 
non-sticky, hot particles situated within the fluid-bed reaction zone. The 
feed particles, in accordance with the invention, are preheated to a 
temperature within their plastic transformation range prior to injection 
into the fluid-bed reaction zone. The hot non-plastic particles or 
materials at bed temperature transfer heat to the entering feed coal 
particles. The molten feed coal particles form partial bonds with these 
dry, hot particles that have previously passed through the plastic 
transformation temperature range as well as bonding with one another. The 
extent of average bed particle growth is determined by a dynamic 
equilibrium in which particle growth is balanced by particle withdrawal 
and deagglomeration. Coal-to-coal bonds are relatively strong whereas 
coal-to-char bonds are relatively weak, depending on the extent of 
solidification which occurs prior to contact of the particles. Two freshly 
molten coal particles tend to fuse into an indivisible agglomerate, 
whereas fresh coal would be linked to a char particle by a weaker bond. 
With high velocity, high energy injection, rapid dispersion of the entering 
coal particles occurs, and the fresh particles thus traverse the plastic 
transformation temperature range with a minimum number of sticky particles 
contacting one another and at an overall mechanical or kinetic energy 
input level sufficient to break up the weaker bonds of the coarser 
agglomerated particles. Consequently, agglomerating or caking coals can be 
injected into the fluid-bed reaction zone and devolatilized without 
defluidization occurring as a result of excessive particle agglomeration. 
This invention is particularly applicable as an improvement in a 
hydrocarbonization process utilizing a dense phase fluid-bed. By the term 
"hydrocarbonization" as employed throughout the specification is meant a 
pyrolysis or carbonization in a hydrogen-rich atmosphere under such 
conditions that significant reaction of hydrogen with coal and/or 
partially reacted coal and/or volatile reaction products of coal occurs. 
By dense phase as used throughout the specification is meant a 
concentration of solids in fluidizing gas of from about 5 pounds to about 
45 pounds of solids per cubic foot of gas. In a hydrocarbonization process 
employing a dense phase fluid-bed, the particles in the bed are 
substantially backmixed, which ensures a near uniform-composition of 
particles throughout the bed. Since the fluid-bed is in dense phase, fresh 
coal particles should enter the bed at a velocity sufficient to penetrate 
and spread rapidly throughout the bed. 
The overall mechanical or kinetic energy level necessary and sufficient to 
prevent excessive particle agglomeration will vary for each particular 
coal or carbonaceous feed material. The minimum energy required for any 
particular coal can readily be determined by incrementally decreasing the 
high injection velocity to the point of bed failure. For such purposes, 
the bed velocity will conveniently be maintained at a constant rate, with 
shroud gas being passed through the shroud passages of the injection 
nozzle at a conventional velocity, e.g. about 35-100 ft./sec., to keep the 
nozzle-tip clean and for temperature control purposes. The particular high 
velocity injection-hot coal conditions employed in the practice of the 
invention for any such coal may be varied, as will be appreciated by those 
skilled in the art, depending on the overall energy input of the injection 
gas, the shroud gas, the bed fluidizing-reagent gas and any attrition jets 
employed. It will be further appreciated that the energy-to-coal ratio and 
the gas-to-coal ratio of the overall plant design can be adjusted by a 
variation of such energy and gas input factors to achieve efficient 
overall technical and economic performance. The invention, at the 
particular high velocity coal injection employed, minimizes nozzle erosion 
by the preheating of the fresh feed to a temperature within its plastic 
transformation range without, at the same time, causing undue 
agglomeration of the fresh feed particles. 
A velocity rate useful in the method of this invention may be obtained by 
any suitable means. For example, an inlet nozzle means having a passageway 
whose cross-sectional area is tapered, narrowed or necked down may be 
employed to accelerate the coal particles to a high velocity. In addition, 
process gas may be physically added to the fluidized coal stream as it 
enters the inlet to the reactor. The addition of process gas increases the 
flow rate of the fluidized stream and hence the velocity of the coal 
particles. An amount of process gas sufficient to achieve the desired 
entrance velocity of coal particles should be used. 
Since the fluidized coal particles are transported through the lines in a 
dense phase flow, a flow or transport rate velocity equivalent to the 
injection velocity in the reactor is usually unnecessary and undesirable 
due to the abrasive characteristics of coal. A high velocity flow of coal 
particles throughout the lines would have required wear plates to be 
installed throughout the lines to control the otherwise rapid erosion rate 
of the lines, such wear plates being an undesirable expense. However, 
according to the present invention, only a small surface area in the 
immediate vicinity of the reactor, will be exposed to abrasive wear and 
this part may be replaced readily and economically with little or no 
downtime of the system. 
For example, an inlet means comprising a material having a wear-resistant 
surface may preferably be employed in this invention as a means for 
increasing the velocity of coal particles entering the reaction zone and 
as a means of controlling the manner of entry. Use of such an inlet means 
lengthens the wear time of the surface exposed to the high erosion rate 
caused by the high velocity flow of coal particles. Suitable 
wear-resistant surface may be composed of materials such as tungsten 
carbide, silicon carbide or other wear-resistant materials known in the 
art in any combination or mixture thereof. For clarity and illustrative 
purposes only, the description of this invention will be mainly directed 
to use of tungsten carbide as the wear-resistant surface of the material 
that reduced erosion in the lines although any number of other 
wear-resistant materials can be used successfully according to this 
invention. 
An inlet means such as a nozzle which comprises a transfer line having a 
reduced or constructed cross-sectional area may be employed in the method 
of this invention. The length to cross-sectional area ratio of the nozzle 
should be sufficiently large enough so that the desired velocity of 
injection for the solid coal particles or non-vaporizable recycle oil may 
be achieved. A length to cross-sectional area of this section of transfer 
line of greater than about 5 to 1 is desirable, greater than about 10 to 1 
preferable. This allows for a finite distance which the coal particles 
and/or vaporizable recycle oil require for acceleration to the velocity 
approaching that of the carrying gas. The feed particles may be introduced 
into the reaction zone in any convenient direction, i.e. upward, downward, 
sideways or otherwise. For example, the feed particles may be introduced 
into the reaction zone from the side thereof in a substantially 
horizontal, sideward direction. The feed may, furthermore, be introduced 
into the reaction zone through two or more injection points or nozzles 
positioned vertically along the side of the reaction zone, including 
embodiments in which the particles are introduced into the reaction zone 
through injection points located in essentially opposed positions on the 
wall of the reaction zone. In certain embodiments, a multiplicity of 
injection points may be employed. It may also be desirable to withdraw 
particles from the bottom of the reaction zone. 
In particular embodiments of this invention, it is feasible to introduce a 
fluidized stream of coal feed particles into the lower portion of a 
substantially vertical fluid-bed reaction zone. More particularly, the 
feed particles are introduced into the reaction zone through at least one 
inlet means in a reactor in a vertically upward direction. The inlet means 
is situated substantially in the vicinity of the vertical axis at or near 
the reactor borrom. The coal particles are introduced at a velocity 
sufficient to mix the fresh coal, in some embodiments having a preheat 
temperature below the plastic transformation-temperature, rapidly with 
non-agglomerating particles such as partially reacted coal and char 
particles in the reaction zone at the reaction temperature thereby 
substantially preventing agglomeration of the fluid-bed. 
In a vertical reactor, the natural circulation of coal particles within the 
fluid-bed reaction zone is a complex flow pattern. However, it may be 
described approximately by dividing the reaction zone into two concentric 
sub-zones, an inner sub-zone and an outer sub-zone surrounding the inner 
sub-zone. In the inner sub-zone which is situated substantially within the 
axially central portion of the reactor, coal particles flow in a generally 
ascending path. In the outer sub-zone which is situated substantially near 
the walls of the reactor, coal particles flow in a generally descending 
path. Advantages of introducing the coal particles into the fluid-bed 
through the bottom of the reactor in an essentially vertically upwards 
direction are that the natural circulation of coal particles in the 
fluid-bed is enhanced and that the coal particles get at least a minimum 
residence time. Introduction of coal particles into the fluid-bed through 
the bottom of the reactor promotes a channeled circulation of particles 
within the reaction zone along the natural circulation path. Circulation 
eddies, are thus enhanced and promote the dispersion of the entering coal 
particles with a matrix of non-agglomerating particles within the 
fluid-bed reaction zone. 
The fluidized coal particles should be introduced into this inner sub-zone, 
the central upflow zone within the reactor. The central upflow zone 
extends radially from the vertical axis of the reactor to an area where 
the outer sub-zone, the peripheral downflow zone begins. It is essential 
that the coal particles be introduced into the central upflow zone in 
order to avoid striking the walls of the reactor or entering the 
peripheral downflow zone. The coal particles may be introduced through the 
base or bottom of the reactor at one or more inlets situated in the 
vicinity of the point where the vertical axis of the reactor intersects 
the base of the reactor. 
To minimize injection nozzle erosion without, at the same time, causing 
excessive particle agglomeration, the coal or other carbonaceous feed 
particles are preheated to a temperature within the plastic transformation 
temperature range, which varies for different feed materials but is 
generally in the range of from about 280.degree. C. to 400.degree. C., 
commonly in excess of about 325.degree. C., e.g. from about 340.degree. C. 
to about 375.degree. C. The reaction temperature within the fluid-bed 
reaction zone is generally maintained above about 450.degree. C. for known 
coal conversion processes with such temperatures being generally from 
about 500.degree. C. to about 750.degree. C., commonly from 500.degree. C. 
to about 600.degree. C. in hydrocarbonization. At high injection 
velocities, particularly in excess of about 400 ft./sec., the mechanical 
energy input is sufficient to break down the weaker bonds of the coarser 
agglomerates, thereby substantially preventing excess agglomeration and 
defluidization despite the preheating of the feed particles to a 
temperature within their plastic transformation temperature range prior to 
being rapidly and directly injected into the reaction zone at such high 
injection velocities. 
It has been discovered that introducing a fluidized stream of coal 
particles into a dense phase, fluid-bed reaction zone at a velocity of 
more than about 200 feet per second in a manner described hereinabove 
substantially prevents excessive agglomeration or caking of the fluid-bed 
by the imparting of sufficient mechanical energy to the reaction zone to 
break up the coarser agglomerates and to rapidly and uniformly disperse 
the fresh particles within the bed. When a lower injection velocity, for 
example, about 100 feet per second is used, without other modifications 
from conventional practice, agglomeration of the fluid-bed is not 
prevented. In order to substantially prevent agglomeration of the 
fluid-bed reaction zone, coal should be introduced at a high velocity into 
the zone in a high velocity, high kinetic or mechanical energy stream, 
i.e. at a velocity more than about 200, and preferably more than about 
400, feet per second, corresponding to an energy-to-coal ratio of at least 
about 10.times.10.sup.-4, preferably at least about 40.times.10.sup.-4, 
horsepower-hours per pound of coal introduced. The energy-to-coal ratio, 
as referred to herein, is the ratio of the kinetic horsepower (in the 
injection jet as calculated by the adiabatic expansion of the feed 
mixture) to the coal feed rate. "Reaction zone" as used throughout the 
specification is meant to include that area wherein carbonaceous, 
combustible, solid and sometimes liquid particles, are reacted to form 
char, liquid and/or vapor fuel products in coal conversion processes such 
as carbonization, gasification and dry hydrogenation (hydrocarbonization). 
A zone of reaction can also be referred to by the name of the process 
e.g., hydrocarbonization zone is the reaction zone in a hydrocarbonization 
process. 
This invention is applicable to the various coal conversion processes 
mentioned hereinabove. For example, a hydrocarbonization process can be 
improved to handle both agglomerating and/or non-agglomerating coals in a 
continuous manner and maintain fluidization of the fluid-bed. In a 
hydrocarbonization process, a dense phase flow of coal particles may be 
passed through a preheating zone before entering a fluid-bed 
hydrocarbonization zone wherein the coal particles are rapidly heated in 
the presence of a hydrogen-rich, essentially oxygen-free gas, to an 
elevated temperature above about 450.degree. C. where the desired 
reactions can occur. The improvement according to this invention comprises 
introducing the preheated fluidized coal particles into the fluid-bed, 
through the bottom of a hydrocarbonization zone in an essentially 
vertically upwards direction or otherwise as herein provided, at a high 
velocity. This rapidly brings the entering coal particles to a non-sticky, 
high temperature, partially reacted state without their contacting too 
many coal particles also traversing the plastic transformation-temperature 
range. The preheated, particulate coal in a fluidized state is introduced, 
in some embodiments, into a fluid-bed hydrocarbonization zone in a 
vertically upwards direction as described hereinabove at a velocity of 
more than about 200 feet per second and more preferably at a velocity of 
more than about 400 feet per second. 
Coals have been classified according to rank as noted in the following 
table, Table A: 
TABLE A. 
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Classification of Coals by Rank..sup.a 
(Legend: F.C. = fixed carbon; V.M. = volatile matter; B.t.u. = 
British thermal units) 
Limits of fixed carbon 
Class Group or B.t.u., ash free basis 
__________________________________________________________________________ 
1. 
Meta-anthracite 
Dry F.C., 98% or more 
(dry C.M., 2% or less) 
2. 
Anthracite Dry F.C., 92% or more 
and less than 98% (dry 
V.M., 8% or less and 
I. Anthracite more than 2%) 
3. 
Semianthracite.sup.b 
Dry F.C., 86% or more 
and less than 92% (dry 
V.M., 14% or less and 
more than 8%) 
1. 
Low-volatile bitumi- 
Dry F.C., 78% or more 
nous coal and less than 86% (dry 
V.M., 22% or less and 
more than 14%) 
2. 
Medium-volative bitu- 
Dry F.C., 69% or more 
minous coal 
and less than 78% (dry 
V.M., 31% or less and - more than 22%) 
II. 
Bituminous.sup.d 
3. 
High-volatile A bitu- 
Dry F.C., less than 69% 
minous coal 
(dry V.M., more than 31%) 
4. 
High-volatile B bitu- 
Moist.sup.c B.t.u., 13,000 or 
minous coal 
more and less than 14,000.sup.e 
5. 
High-volatile C bitu- 
Moist B.t.u., 11,000 or 
minous coal.sup.f 
more and less than 13,000.sup.e 
1. 
Sub-bituminous A coal 
Moist B.t.u., 11,000 or 
more and less than 13,000.sup.e 
III. 
Sub- 2. 
Sub-bituminous B coal 
Moist B.t.u., 9,500 or more 
bituminous and less than 11,000.sup.e 
3. 
Sub-bituminous C coal 
Moist B.t.u., 8,300 or more 
and less than 9,500.sup.e 
1. 
Lignite Moist B.t.u., less than 
IV. 
Lignitic 8,300 
2. 
Brown coal Moist B.t.u., less than 
8,300 
__________________________________________________________________________ 
.sup.a This classification does not include a few coals that have unusual 
physical and chemical properties and that come within the limits of fixed 
carbon or B.t.u. of the highvolatile bituminous and subbituminous ranks. 
All of these coals either contain less than 48% moisture and ash free 
fixed carbon or have more than 15,500 moist, ash free B.t.u. 
.sup.b If agglomerating, classify in low volatile group of the bituminous 
class. 
.sup.c Moist B.t.u. refers to coal containing its natural bed moisture bu 
not including visible water on the surface of the coal. 
.sup.d It is recognized that there may be noncaking varieties in each 
group of the bituminous class. 
.sup.e Coals having 69% or more fixed carbon on the dry, 
mineralmatter-free basis shall be classified according to fixed carbon, 
regardless of B.t.u. 
.sup.f There are three varieties of coal in the highvolatile C bituminous 
coal group, namely, Variety 1, agglomerating and nonweathering; Variety 2 
agglomerating and weathering; Variety 3, nonagglomerating and 
nonweathering. 
Source: A.S.T.M. D38838 (ref. 1). 
Agglomerating coals, such as most bituminous and some sub-bituminous coals, 
are strongly agglomerating in a hydrogen atmosphere. They can not be 
handled conventionally without a pretreatment step. These coals may now be 
handled without an injurious degree of defluidization by the process of 
this invention alone or in combination with a pretreatment step, if 
necessary. If a pretreatment step is necessary, the needs for pretreatment 
are milder and cost less. For example, at present even after heavy 
pretreatment, the use of a highly agglomerating coal such as Pittsburgh 
Seam Coal in a hydrocarbonization process presents the problem of 
agglomeration occurring in the fluid-bed. However, it is beneficial to use 
the process of this invention to overcome this agglomerating problem. 
Those skilled in the art will recognize that any number of suitable 
pretreatment steps may be applied in combination with the process of this 
invention for the handling of coals which are either highly agglomerating 
or highly agglomerating in a hydrogen-containing atmosphere. These 
pretreatment steps include, for example, but are not limited to, chemical 
pretreatment such as oxidation or mixing with inert solids such as recycle 
char. 
The manner in which the invention is carried out will be more fully 
understood from the following description when read with reference to the 
accompanying drawing which represents a semi-diagrammatic view of an 
embodiment of a system in which the process of this invention may be 
carried out. 
FIG. 1 illustrates coal supply vessels 10 and 16, a coal feeder 22, a 
preheater 30 and a reactor vessel 40. Lines are provided for conveying 
finely divided coal through the vessel in sequence. A line 26 conveys the 
coal from the pick up chamber 18 to the preheater 30. A line 34 conveys 
the coal from preheater 30 into the reactor vessel 40. A line 44 conveys 
devolatized coal (termed "char") from the reaction vessel 40 for recovery 
as solid product or for recycle. A line 42 is provided for conveying 
liquid and vapor products from the reaction vessel 40 for further 
processing and/or recycle. 
According to the process of this invention, the feed coal is in particulate 
form, having been crushed, ground, pulverized or the like to a size finer 
than about 8 Tyler mesh, and preferably finer than about 20 Tyler mesh for 
lower rank coals while finer sizes, e.g. -60 mesh US, are employed for 
bituminous coals. Furthermore, while the feed coal may contain absorbed 
water, it is preferably free of surface moisture. Coal particles meeting 
these conditions are herein referred to as "fluidizable." Any such 
absorbed water will be vaporized during preheat. Moreover, any such 
absorbed water must be included as part of the inert carrying gas and must 
not be in such large quantities as to give more carrying gas than 
required. 
The coal supply vessels 10 and 16 each can hold a bed of fluidizable coal 
particles, which are employed in the process. Coal supply vessel 10 is 
typically a lock-hopper at essentially atmospheric pressure. Coal supply 
vessel 16 is typically a lock-hopper in which fluidized coal can be 
pressurized with process gas or other desired fluidization gases. 
Operation of vessels 10, 16 and 22 can be illustrated by describing a 
typical cycle. With valves 14 and 17 closed, lock-hopper 16 is filled to a 
predetermined depth with coal from lock-hopper 10 through open valve 12 
and line 11 at essentially atmospheric pressure. Then, with valves 12 and 
17 closed, lock-hopper 16 is pressurized to a predetermined pressure above 
reaction system pressure through open valve 14 and line 13. Valves 12 and 
14 are then closed and coal is introduced into fluidized feeder vessel 22 
through open valve 17 and line 20. The cycle about lock-hopper 16 is then 
repeated. A typical time for such a cycle is from about 10 to about 30 
minutes. With valve 17 closed, fluidized coal is fed at a predetermined 
rate through line 26 to the downstream-process units. Other variations of 
the feeding cycle to the fluidized feeder are possible, of course, but 
they are not illustrated herein since they do not form the inventive steps 
of this process. 
In fluidized feeder 22, a fluidizing gas passes through line 24 at a low 
velocity sufficient to entrain the fluidizable coal and convey it in dense 
phase flow through line 26 and into the bottom of coal preheater 30, or 
directly to line 34 if no preheat is required. Alternately, additional gas 
could be added to the line conveying the coal in a dense phase flow 
through line 26 to assist in the conveyance. Any non-oxidizing gas can be 
used as the fluidizing gas, e.g. fuel gas, nitrogen, hydrogen, steam and 
the like. However, it is preferable, in general, to use reaction process 
gas or recycle product gas. 
Coal preheater 30 is a means to rapidly preheat, when desirable, the finely 
divided coal particles, under fluidized conditions, to a temperature below 
the minimum temperature for softening or significant reaction range, in 
the substantial absence of oxygen. The maximum allowable temperature of 
heating is in the range of from about 325.degree. C. to about 400.degree. 
C., depending on the feed material employed where preheating to below the 
plastic transformation temperature range is employed. Preheating to below 
about 300.degree. C. is common in such embodiments. The stream of 
gas-fluidized coal in dense phase is heated upon passing rapidly through 
the heater having a very favorable ratio of heating surface to internal 
volume. The coal is heated in the heater 30 to the desired temperature by 
any convenient means of indirect heat exchange; e.g., by means of radiant 
heat or a hot flue gas such as depicted in FIG. 1 as entering the bottom 
of heater 30 through line 28 and exiting at the top of the heater 30 
through line 32. 
Preheated fluidized coal particles exit the preheater 30 through line 34 
and enter at or near the bottom of the reactor vessel 40 substantially 
near the center of the bottom. In this illustrated embodiment, the coal 
particles are introduced into the fluid-bed reaction zone through the 
reactor bottom at a high velocity. This high velocity may be achieved by 
accelerating the fluidized stream of coal particles to the desired 
velocity by addition of an accelerating gas and/or along a constricted 
path of confined cross-section. A nozzle, narrow inlet port, tapered 
channel or any inlet means which narrows, constricts or necks down the 
cross-sectional area of the passageway to the inlet where the fluidized 
coal particles enter the reactor may be used to accelerate the fluidized 
stream of particles to the desired velocity. The stream of preheated, 
fluidizable coal particles is introduced into the central upflow zone of 
the fluid-bed within the reaction vessel at the high velocity in an 
essentially vertically upwards direction, preferably through the bottom of 
the reaction vessel. 
Recycle oil may also be fed into reactor 40 through line 36. Injection of 
the recycle is also preferably at a stream velocity of about 200 feet per 
second or greater, and more preferably about 400 feet per second or 
greater into the central upflow zone of the fluid-bed of the reactor 
through the bottom of the reactor vessel in an essentially vertically 
upwards direction. Like the entering coal particles, the recycle oil 
stream follows a substantially ascending path about a substantially 
axially central portion of the reaction vessel. In the injection of the 
recycle oil and fluidizable coal particles, it is essential that they be 
introduced into the reactor vessel in such a way that they do not 
immediately and directly strike the walls of the reactor vessel, a result 
which could lead to unnecessary and undesirable agglomeration. 
Only one inlet each for entry of the preheated coal particles and the 
recycle oil is shown in FIG. 1. These inlets may also represent a 
multiplicity of inlets for ease of operation of this process. A 
multiplicity of inlets may be desirable, for example, where the reactor is 
large, or when separate recycle streams of oil are being injected into the 
reactor. The entry points for the coal particles and/or recycle oil are 
preferably situated near the point where the vertical axis intersects the 
reactor bottom. Each stream of coal particles and/or recycle oil is 
preferably introduced at a high velocity at each inlet in an essentially 
vertically upwards direction, the inlets situated in or near the reactor 
bottom substantially near the point where the vertical axis intersects the 
reactor bottom. In this manner, the separate streams of entering 
carbonaceous materials are kept separate and apart until rapidly mixed in 
the fluid-bed with partially reacted coal and char particles. 
The entering carbonaceous materials are reacted with a suitable reagent in 
the reaction zone at a temperature above about 450.degree. C. or 
500.degree. C. 
Char from reactor vessel 40 is continuously removed through line 44. 
Liquid and vapor products are removed from the reactor vessel 40 through 
line 42. Fluidization gas is fed into the reactor vessel 40 through line 
38, the type gas depending on the type process involved. For example, 
steam or steam and oxygen are fed into a gasifier in a gasification 
process; a non-reacting gas is fed into a carbonizer in a carbonization 
process; and a hydrogen-containing, substantially oxygen-free gas is fed 
into a hydrocarbonizer in a hydrocarbonization process. 
As disclosed herein, further advantages unappreciated heretofore in the art 
are obtained by preheating fluidized coal particles in preheater 30 to a 
temperature essentially within the plastic transformation temperature 
range of the particles. The thus preheated particles exit preheater 30 
through line 34 and pass rapidly and directly to the bottom of reactor 
vessel 40 substantially near the center of the reactor bottom in the 
embodiment shown in the drawings. The coal particles are introduced into 
the fluid-bed reaction zone at a high injection velocity, the lubricity of 
the fresh feed material at the higher than conventional preheat 
temperature tending to minimize undesired nozzle erosion while the rapid 
and direct injection of the particles into the reaction zone precludes 
excess agglomeration of particles and resultant defluidization. As noted 
above, it will be appreciated in the art that, in other embodiments of the 
invention, the fresh feed particles can be introduced into reactor 40 in 
any other direction. In particular embodiments, the injection points may 
be located in essentially opposed positions on the wall of reactor 40 for 
further turbulent mixing. In other embodiments, the feed material may be 
passed through line 34 for downward injection into reactor 40. It will 
also be understood that reactor 40 may be constructed with a lower 
reaction zone, an enlarged upper zone and a cone-like transition zone, the 
upper zone having a lower bed velocity facilitating separation of gaseous 
materials from the bed and minimizing undesired carry-over of fines in the 
gaseous effluent stream. It will be further understood that the feed inlet 
nozzle means will be positioned substantially at the wall of the reaction 
vessel, e.g. substantially at the bottom of the reaction zone in the 
embodiment shown in the drawing, but may extend somewhat into said zone. 
In the illustrated embodiment, inlet nozzle means 46 may extend, for 
example, 2 ft. or more upward into the reaction zone. The injection point 
need not extend appreciably into the interior of the fluid-bed region, 
however, as is required in the Phinney patent, U.S. Pat. No. 2,709,675 
which relates to low speed coal injection, preferably in conjunction with 
a draft-tube positioned within the fluid-bed reaction zone. Shroud gas is 
passed in a conventional manner through shroud passage 48 to maintain the 
nozzle tip clean and free of clogging problems and to prevent overheating 
of the coal. 
The following examples are illustrative of the concept of this invention, 
demonstrating the method of preventing agglomeration of coal in fluidized 
bed processes via the high velocity injection of coal particles into a 
reaction zone. 
EXAMPLE I 
The apparatus employed, shown schematically in the drawings, comprised two 
coal feed lock-hoppers (10,16) connected in parallel to a fluidized feeder 
22, a preheater 30 and reactor 40. The entire coal conveying line was 
constructed of 3/8-inch I. D. by 5/8-inch O. D. tubing. The two coal feed 
lock-hoppers (10, 16) that fed the fluidized feeder alternately each had a 
7-inch I. D. and height of 8 feet. The fluidized feeder 22 had a 24-inch 
I. D. and h height of 20 feet. The preheater 30, a lead bath heated by 
"surface combustion" burners had a 24-inch I. D. and height of 12 feet. 
The reactor 40 had an 11-inch I. D. fluid-bed, a bed depth of 171/2 feet 
an outside cross-sectional area of 0.66 sq. ft. 
The average velocity through the dense phase coal feed line was not 
particularly high, the maximum velocity being approximately 40 feet per 
second at the inlet to the reactor and only 15 feet per second at the 
outlet of the coal feeder, erosion of the pipe at these velocities still 
remaining at an acceptable level. Attempts to feed the coal into the 
reactor at velocities of approximately 100 feet per second resulted in 
agglomeration and coking-up of the fluid-bed. A 15/32-inch diameter 
tungsten-carbide nozzle was used to increase the rate at which the 
fluidized coal-hydrogen stream was introduced into the reactor to 200 feet 
per second and provide an erosion resistance surface. 
In operation, the reactor was filled with coal and slowly heated up toward 
the target conditions and gas flows and pressures were established. 
Hydrogen was employed as the gas phase. When the target conditions were 
established the coal feed was begun. On the termination of the run the 
reactor was opened up. No large agglomerates or coke particles were found. 
Operating conditions during the hydrocarbonization are shown in Table I 
below: 
TABLE I 
__________________________________________________________________________ 
LAKE DE SMET COAL 
(Operating Conditions) 
Run Number 1 2 3 4** 
__________________________________________________________________________ 
Reactor Pressure 
500-600 psig. 
600 psig. 
400-1000 psig. 
700 psig. 
Reactor Temperature 
*470.degree. C.-520.degree. C. 
*470.degree. C.-520.degree. C. 
480.degree. C. to 570.degree. C. 
520.degree. C.-560.degree. C. 
Fluidization Velocity 
0.5 ft/sec 
0.5 ft/sec 
0.25 ft/sec-0.5 ft/sec 
0.5 ft/sec 
Coal Feed Rate 1000-1200 lb/hr 
1000-1200 lb/hr 
600-1000 lb/hr 
1000 lb/hr 
Feed Gas to the Reactor 
Hydrogen Hydrogen Hydrogen Hydrogen 
Length of Run 45 hours 34 hours 78 hours 29 hours 
Coal Stream Injection Velocity 
200 ft/sec 
200 ft/sec 
200 ft/sec 
200 ft/sec 
Nominal Solids Residence 
18-22 minutes 
18-24 minutes 
19-46 minutes 
9.4 minutes 
time in bed 
__________________________________________________________________________ 
*Initially 470.degree. C. and increased in 10.degree. C. increments every 
6 hours with the added restriction that the reactor was cooled to 
450.degree. C.-470.degree. C. after a coal feed stoppage and before 
starting the coal feed again. 
**Bed depth of the reactor was shortened to 7 ft. 2 inches for this run. 
The analysis of the feed, is summarized in TABLE II below: 
TABLE II 
______________________________________ 
LAKE DE SMET COAL, WYOMING, 
SUBBITUMINOUS C (ANALYSIS) 
Moisture and Ash Free Basis 
Weight Percent 
______________________________________ 
C 72.0 
H 5.3 
N 1.3 
S 1.0 
O 20.4 
Ash 11.9 (dry basis) 
Water 30 (as received) 
______________________________________ 
EXAMPLE II 
Two additional runs were conducted employing apparatus and procedures 
similar to those employed in Example I, except that oil, the higher 
boiling fractions (all product boiling above 235.degree. C.) of the liquid 
product, was recycled to the reactor. These additional runs were conducted 
to determine whether a high velocity injection of heavy oil could be fed 
to the reactor without agglomerating the fluid-bed. The oil recycle 
equipment added to the pilot plant apparatus comprised a storage tank, to 
hold the recycle oil, an oil preheater to preheat the oil prior to 
injection into the reactor. 
The main hydrogen stream to the reactor was split into two roughly equal 
streams, each of which was preheated to 300.degree. C. to 350.degree. C. 
The heavy recycle oil was pumped into one of these hydrogen streams and 
injected into the reactor through a 1/4-inch diameter tungsten carbide 
nozzle at a stream velocity of approximately 400 feet per second. The 
nozzle, which pointed vertically up the reactor, was located in the center 
of the reactor bottom 5 feet above the coal inlet. The other hydrogen 
stream was mixed with preheated coal, and introduced into the bottom of 
the reactor through a 15/32-inch diameter tungsten-carbide nozzle at 
approximately 160 feet per second in a vertically upwards direction. The 
data for these runs are summarized below in Table III. 
TABLE III 
______________________________________ 
Run 1 2 
______________________________________ 
Coal Feed Rate 1000 lb./hr. 1000 lb./hr. 
Coal Feeder Pressure 
1100 psig. 1100 psig. 
Reactor Pressure 
500 psig. 500 psig. 
Reactor Temperature 
550 C 580 C 
Reactor Fluidization 
Velocity 0.5 ft./sec. 0.5 ft./sec. 
Length of Run 5 hrs. 5 hrs. 
Recycle Oil Feed Rate 
100 lb./hr. 240 lb./hr. 
Coal - H.sub.2, Inlet Velocity 
160 ft./sec. 160 ft./sec. 
Oil - H.sub.2, Inlet Velocity 
420 ft./sec. 420 ft./sec. 
______________________________________ 
No problems were encountered in making these runs. There was no evidence of 
agglomeration in the fluid-bed, even when injecting oil at the 240 lb./hr. 
rate. 
EXAMPLE III 
The bench-scale apparatus employed in this example comprised a pulverized 
solid hopper having a solid's capacity of 4.5 liters and constructed from 
a 3-inch diameter by 4-foot high schedule 80 carbon steel pipe; a reactor 
was made of 1-inch I. D. by 9-inch high stainless steel tube having a 
1/4-inch wall thickness and an expanded head 4-inches high and 2 inches I. 
D.; solids overflow line constructed of 1/2-inch Schedule 40 pipe; a vapor 
line constructed from 1/8-inch O. D. stainless steel tubing; and a solids 
feeder. Two liquid feed pumps, Lapp Microflow Pulsafeeders were used, one 
to feed the liquid being investigated and the other to feed water for 
steam generation. Electrically heated liquid and water vaporizers and 
superheaters constructed of 1/4-inch O. D. stainless steel tubing were 
installed between the feed pumps and the feed injection nozzle to the 
reactor. Thermocouples located 3, 6, 8 and 11-inches from the bottom of 
the reactor were installed in a 1/4-inch O.S. thermowell placed axially in 
the center of the reactor. The lower three thermowells were in the 
fluidized bed while the upper thermocouple was in the vapor space above 
the bed. 
In operation, tars boiling about 235.degree. C. obtained from 
hydrocarbonization of Lake de Smet Coal were employed as the feedstock to 
the reaction zone for conversion to oils boiling below 230.degree. C. The 
tars were distilled from the whole liquid product obtained from the 
hydrocarbonization into various distillation fractions and a blend of 
these distillation fractions used in this example had a nominal 
atmospheric temperature range for 75% of the tar between 235.degree. C. 
and 460.degree. C. The remaining 25% boiled above 460.degree. C. 
The solids feed hopper was filled with Lake de Smet hydrocarbonization char 
as described hereinabove. The water and tar feed reservoirs were filled 
and heated to operating temperature. During the heat up period, a 
predetermined flow of hydrogen passed through the empty reactor. As soon 
as operating conditions were approached, the char feed and water feed 
(superheated steam by the time it entered the reactor through the 
injection orifice) were started. The three thermocouples located in the 
fluidized bed, at the levels indicated hereinabove, served as an 
indication of bed behavior. Attempts to feed this tar stream at velocities 
of 100, 200 and 300 feet per second resulted in rapid agglomeration of the 
fluidized reactor bed. A 26-gauge hypodermic needle used was to achieve a 
400 feet per second injection velocity of the whole tar feed. Using this 
inlet velocity for the whole feed, coking up of the fluidized bed within 
the reactor was prevented under the following operating conditions 
contained in Table IV. 
TABLE IV 
______________________________________ 
OPERATING CONDITIONS - 
LAKE DE SMET COAL 
______________________________________ 
Pressure 150 psig. 
Hydrogen Partial Pressure 
115 psig. 
Residence time of Vapors in Char Bed 
Based on Superficial Linear Velocity 
1.33 sec. 
Char Feed 250 g/hr. 
Oil Feed Rate 2 ml/min. 
Water (as steam) Feed 3 ml/min. 
Hydrogen Flow to Reactor 35 SCFH 
Moles Hydrogen/Moles Oil 45/1 
Temperature 650.degree. C. 
Superficial Linear Velocity of 
Hydrogen 0.5 ft./sec. 
Rim of Run 5 hrs. 
Fluidizing Gas Hydrogen 
______________________________________ 
EXAMPLE IV 
100 pounds per hour of Pittsburgh No. 8 seam coal, -20 mesh, are introduced 
into a low temperature, fluid-bed reactor for pyrolysis at a reactor 
temperature of 540.degree. C. to obtain liquid products, gaseous fuel and 
dry char. Pittsburgh No. 8 seam coal is a highly swelling, agglomerating, 
high volatile A bituminous coal. Nominal residence time of the coal and 
the product char in the reactor bed is 15 minutes. When the coal is 
introduced into the reactor bed with recycled product gas at a coal and 
gas injection velocity of 20 feet per second, agglomeration of the reactor 
bed begins immediately. Within 30 minutes, the bed is highly agglomerated 
so that no fluidization occurs and no further coal can be injected as a 
practical matter. 
However, when fresh coal is introduced into the fluidbed reactor at 
injection velocities of 200, 300 and 400 feet per second, respectively, a 
fluid-bed at a reaction temperature between about 500.degree. C. and about 
700.degree. C. is maintained without substantial agglomeration. The fresh 
entering coal rapidly mixes with the partially carbonized coal (char) 
circulating in the bed, so that as the fresh coal particles undergo 
plastic transformation and become sticky, the fresh coal particles 
primarily see particles which have already undergone plastic 
transformation and are now non-sticky. Carbonization products, gases, tars 
and other liquids, water and char are continuously withdrawn from the 
carbonization reactor. 
EXAMPLE V 
In an agglomerating ash gasifier of the type described in U.S. Pat. No. 
3,171,369, 1000 pounds per hour of fresh Pittsburgh No. 8 seam coal, -60 
mesh, is gasified at a temperature between about 816.degree. C. and about 
1000.degree. C. with steam. Heat is provided by circulation to the 
gasifier of about 12,000 pounds per hour of agglomerated ash particles 
from a char fired, fluid-bed combustor. When the fresh coal is injected 
into the fluid-bed of ash and partially reacted coal, at a velocity of 20 
feet per second with steam, partial agglomeration occurs. Large aggregates 
of char are formed which cannot be separated from the ash agglomerates and 
poor fluidization and soon poor thermal efficiency results. It is 
essential to the operation of the process that the coal, as it carbonizes 
and gasifies, remains free-flowing and finely-divided. 
When the velocity of the injected Pittsburgh No. 8 coal and steam is 
increased to 400 feet per second, dispersion within the fluid-bed is 
excellent. No significant agglomeration occurs and separation of the fine 
char formed and the larger denser particles of agglomerated ash is readily 
accomplished. The introduction of the fresh coal into the fluidized, 
generally descending bed of hot agglomerated ash, at a velocity of 400 
feet per second, occurs at a point near the bottom of the bed, but 
somewhat above the bottom to avoid carry-down of coal or char by the 
recycling ash. Injection is in a generally vertical and upward direction. 
This promotes great turbulence of ash, coal and char near the points of 
introduction, which disperses the coal throughout the bed and effectively 
prevents agglomeration. 
EXAMPLE VI 
The advantages of the novel high injection velocity-hot coal embodiments of 
the invention were demonstrated by introducing Illinois No. 6 coal, 
without recycle char and without pretreatment oxidation, upwardly into a 
fluid-bed hydro-carbonization reaction zone at an injection velocity of 
from about 400 to about 480 ft./sec., said feed coal having been preheated 
to a carrier gas/coal mixture temperature of about 390.degree.-400.degree. 
C., i.e. within the plastic transformation temperature range of said coal. 
The initial softening point of the coal was about 325.degree.-350.degree. 
C. The coal particles, which were 60-70%-200 mesh, were fed to the 
reaction zone over a 3-4 hr. period, with the coal feed rate being slowly 
increased from 10 to 22 lb. of coal/hr. The injection gas/coal rate 
decreased from 67 to 34 scf (standard cubic feet) of gas per pound of 
coal. Gas was passed through the shroud passage of the injection nozzle at 
about 70 ft./sec., corresponding to a kinetic energy/coal ratio of 
0.1.times.10.sup.-4 hp-hr./lb. of coal. The injection nozzle was located 
20" above the grid at the bottom portion of the reaction zone. No 
attrition jets were employed. The bed velocity at the bottom of the 
reaction zone was varied from about 1.6 to about 2.0 ft./sec., the bed 
density at this portion of the zone varying from about 13 to about 7.3 
lb./ft.sup.3 over the range of the coal feed rate given above. Three 
inches from the top of said zone, the bed velocity varied from about 2.3 
to about 2.8 ft./sec., with the bed density being in the range of 8 to 11 
lbs./ft.sup.3. The reactor employed had an enlarged upper zone and a 
cone-like transition zone, with the upper zone having a lower bed velocity 
to facilitate separation of gases from solids without excessive carryover 
of fines. The bed velocity in said upper zone ranged from 0.60 to 0.68 
ft./sec. with the bed density being 13-14 lbs./ft.sup.3. No defluidization 
or bed failure was encountered. Rapid dispersion of the feed particles 
with the char in the fluid-bed reaction zone, together with 
deagglomeration due to the mechanical or kinetic energy supplied to the 
reaction zone, served to maintain the average bed size in a range suitable 
for fluidization. The kinetic energy of the high velocity injection gas 
was sufficient, therefore, to avoid excessive agglomeration and to control 
particle size within the reaction zone to a range that could be fluidized. 
Despite the high injection velocity, no observable erosion of the 
injection nozzle occurred. By contrast, a run carried out at 600 ft./sec. 
with a feed comprising 1/2 part recycled char per part of fresh coal was 
observed, at an entrance gas plus coal mixture temperature of about 
323.degree. C., to cause a 0.005" nozzle erosion after 11/2 hr. at said 
injection velocity. Nozzle erosion is a point of concern, therefore, 
particularly when recycle char is mixed with the fresh coal. As indicated 
above, however, nozzle erosion and the premature shut-down of operations 
for nozzle replacement can be avoided by employing high velocity fresh 
coal injection, substantially without recycle char, at temperatures within 
the plastic transformation temperature range of the particles. The hot 
coal has a lubricity when heated to such range, thereby minimizing 
abrasion and resulting nozzle erosion. The fresh, preheated particles are 
injected rapidly and directly into the fluid-bed reaction zone and into 
direct contact with the non-agglomerating particles therein. Under such 
conditions, undue or excessive agglomeration of the fresh feed particles 
is avoided despite the operation at preheat temperatures avoided in the 
art because of the agglomeration that would occur at conventional 
operating conditions. 
EXAMPLE VII 
In operations utilizing the reactor system of Example VI above, the 
indicated Illinois No. 6 coal was injected into the hydrocarbonization 
reactor at an initial injection velocity of 392 ft./sec. at a gas plus 
coal injection temperature of 375.degree. C., which is within the plastic 
transformation temperature range of the coal particles. The coal feed rate 
was about 24-27 lbs./hr., with the injection gas/coal feed rate being 
reduced from an initial 31 to 21 scf of gas per pound of coal. The 
injection velocity was thus decreased incrementally from said 392 to 295 
ft./sec. No attrition jets were employed. Injection nozzle shroud gas was 
employed at a shroud gas velocity of 55 ft./sec., having a shroud kinetic 
energy of 0.1.times.10.sup.-4 hp.-hr./lb. of coal, to keep the nozzle tip 
clean and to avoid overheating of the feed particles. The bed velocity at 
the bottom of the reaction zone was 1.5 ft./ft./sec. with a bed density of 
13 lbs./ft.sup.3. 3" from the top of said zone, the bed velocity was about 
2.0-2.1 ft./sec., with the bed density at this point ranging from about 
7.9 to about 9.8 lbs./ft.sup.3. In the enlarged upper zone, bed velocity 
was reduced to 0.55 ft./sec. at a bed density of 14 lbs./ft.sup.3. 
Excessive agglomeration was avoided under such conditions and no 
noticeable erosion of the injection nozzle occured. Bed failure resulted, 
due to defluidization caused by excessive particle agglomeration, when the 
injection velocity was reduced to below 300 ft./sec. 
It should be noted that excessive agglomeration and defluidization are not 
prevented simply by a high fresh feed injection velocity, but by such a 
high injection velocity of carrier gas and fresh coal or other 
carbonaceous particles at such quantities, or loading levels, as to 
provide sufficient mechanical or kinetic energy to assure that excessive 
agglomeration and resulting defluidization are prevented. Under the 
conditions of EXAMPLE VII, for example, bed failure occurred when the 
injection velocity was reduced to below 300 ft./sec. and the available 
power for controlling the size of particles was inadequate at the loading 
level pertaining to the fluid-bed reaction zone in this instance. The 
invention has been employed, in other examples, with Pittsburg No. 8 as 
the feed coal to achieve the desirable and unique combination of results 
herein disclosed and claimed. 
The invention represents a highly significant advance in the art of feeding 
caking coals or other carbonaceous materials to fluid-bed coal conversion 
operations. The invention enables high velocity injection of such 
materials to be carried out while nozzle erosion is minimized. Despite the 
avoidance in the art of preheat temperatures within the plastic 
transformation temperature range of the particles, the invention enables 
such temperatures to be used to advantage to minimize nozzle erosion 
leading to premature shut-down of operations. Such unique preheat 
temperatures are employed in conjunction with high velocity coal 
injection, without the necessity for admixture with recycle char and/or 
oxidation pretreatment, at kinetic energy levels such as to substantially 
prevent defluidization in the reaction zone despite the preheating of the 
feed particles to their plastic transformation temperature range. 
Sufficient mechanical energy is thus imparted to the reaction zone to 
break up the coarser agglomerates that may form and to rapidly and 
uniformly disperse the fresh feed particles within the fluid bed of 
non-agglomerating particles within the reaction zone. In addition to the 
minimizing of nozzle erosion while substantially avoiding agglomeration, 
the invention provides desirable operating flexibility and advantages 
overcoming the economic disadvantage of high gas/coal ratios associated 
with high injection velocity operations. At the temperature of the coal 
and gas injection mixture as restricted to below the initial softening 
point, i.e. below the plastic transformation range, of the coal in 
conventional practice, addition of gas in excess of that required to 
convey the coal to the reactor, as in high velocity injection, would 
impose a thermal burden on the reactor system. Thus, the thermal energy 
balance around the reactor in such circumstances would require a hotter 
feed temperature for the remaining gas, such as the fluidizing-reagent gas 
as more of the total gas input to the system would be used to provide the 
dilute, easily dispersible, high velocity fresh coal injection jet. This 
consideration would be of particular importance in hydrocarbonization 
where the heat of reaction is only slightly exothermic. 
As the relative ratio of the relatively cold injection gas to hot gas is 
increased, a point is reached at which the additional heat that the hot 
gas is required to supply will call for temperatures that cannot be 
handled without the use of expensive alloys for the hot gas preheater and 
the transfer line to the reaction zone. Operating with the injection 
mixture above the initial softening point temperature of the coal and at 
the high injection velocities employed in the practice of the invention, 
the advantages associated with a diluter injection jet, both in terms of 
dispersion and deagglomeration efficiency, can be achieved while 
minimizing the thermal burden on the reactor. The process of the invention 
enhances the technical and economic feasibility of desirable coal 
conversion operations, provides advantageous flexibility in meeting the 
overall heat and material balance limitations of commercial plant designs, 
and constitutes a major advance in the important efforts to develop 
practical technologies for the use of caking coals in meeting the 
ever-increasing energy requirements of modern industrial societies.