CA1143569A - Enhanced dispersion of agglomerating solids in a fluid-bed reactionzone - Google Patents

Abstract

Abstract of the Disclosure Defluidization due to excessive agglomeration of fresh carbonaceous feed particles in a fluid-bed reaction zone is prevented by utilizing an overall mechanical energy input to the reaction zone above the minimum energy level needed for dispersion of the particular feed and to break up agglomerates that may tend to form upon injection of said fresh particles to said zone. The overall energy input comprises that supplied by the fluidizing-reagent gas employed; by the carrier gas for the fresh carbonaceous feed, either at conventional, low velocities or employed at high velocity and in sufficient quantity to furnish at least half of said overall mechanical energy input to the reaction zone; and by attrition jets positioned to break up agglomerates. At high injection velocities, the fresh particles may be preheated to a temperature within the plastic temperature range for the particles, thereby minimizing nozzle erosion at such high injection velocities without causing undue agglomeration of the particles. A wide variety of desirable processing alternatives may thus be employed while remaining within the permissible limits for the practical operation of fluid-bed reaction zones without defluidization due to excessive agglomeration of fresh coal or other carbonaceous feed materials.

Description

569 ~Y~-3 BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a method of avoiding excessive agglomeration of car~onaceous 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 hydrocarboniza~ion, gasification or carbonization reaction zone Description of the Prior Art Increasing energy needs have focused attention on solid fos~il 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 feetstock. 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 ma;or 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 ~' ~ 9 ~ ~ y~ 3 and non-agglomerating coals become sticky when heated in 6uch an atmosphere. Coal particles begin to become sticky at temperatures in the ~ange of from about 280C, commonly from about 350C to about 500C, depending on the specific properties of the coal, the atmosphere and the rate of heating. Such stic~iness is due to a tarry or plastic-like material forming at or near the surface of each coal p~rticle, by a partial melting or decomposition process. On further heating over a period of time, the tarry or plastic-like material is further ransformed 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 wi~h an in-crease 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 w~en heated in a hydrogen atmosphere, to develop stickiness and transform into substantiaLly 801it char, non-sticky surfaces. "Plastic transformation" is undergone by both normally agglomerating coals and coals w~ich 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 280C, commonly from about 350C, to about 500C. 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 th~
upper limits of said range. Components of the coal par-ticles 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 bafles in the reactor, particularly relatively cool S69 7S'9~-~
walls or baffles. Moreover, contact with other sticky particles while undergoing plastic transformation results in gross particle growth through adherence of stic~y 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 condition~ such as the heatlng rste, final temperature attained, am~ient gas composition, coal type, particle size and total pressure. Even non-agglomerating coals, such as lignites or coals fr~m certain sub-bituminous seams, are ~usceptible 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 1143569 ~ d-3 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 ~rom an external so~rce 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 J
are wasteful o~ energy and are, therefore, co~tly.
Other attempts have included a pretreatment step wherein coal i9 oxidized and/or devolatilized superficially ln 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 hlghly desirable economically to avold 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, US 3,927,996, in which the fines carried ~y~
~ 3~3 overhead by gas from a fluid-bed are monitored and the injection velocity of fresh feed material i8 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 temperatuse in excess of the coal resolidification point by entraining coal particles in a gas stream preheated to a tempersture in excess of about 300F, i,e, about 150C, but below the initial softening point of the coal, For the gasification of bituminous coals, preheat temperatures up to about 550F, i,e, about 285C, 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 gasif1er zone. The in~ection velocity is regulated between superficial gas velocities as low as 15 feet/
second and as high a8 1,000 feet/second in response to variations in the fines content of the overhead gas, Such a system necessarily requires continual processing adgustments that are not desirable in continuous, commercial scale operations, In addition, the intermittent high in~ection velocities ~of the fresh coal introduced into the fluid-bed under the indicated conditions would generally be considered as having a potential for in~ection nozzle eroslon that, if severe, could lead to a need for premature shutdown for nozzle replacement, adversely affecting the overall effective-ness of the coal conversion operation being carried out in the fluid-bed reaction zone, 35G9 ~ y7~ ~
A need thus exists in the art for improved methods ~or 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 in;ection operations must not, on the other hand, introduce peripheral processing disadvantages, such as undue injection nozzle wear or excessive gas consump-tion, that would adversely affect the technical-economic feasibiLity of coal conversion operations.
There also exists in the art a need for a comprehensive, integrated process reconcilin~ the effect of various proce~sing alternatives to assure the successful operation of e~,tablished fluid-bed coal conversion technologies with fresh coal or other solid carbonaceous feed materials having agglomerating tenden-cies under the reaction conditions employed. Thus, the present uncertainties and the potential for defluidi~ation and bed failure when employing variations in resh feed material and/or otherwise desirable processing variations in particular applicatlons or embodime~ts of known coal conversion technologies, ~35~ 7~-~
including those variations necessary in scale-up from small scale pilot studies to larger .scale studies, demonst~ation or commercial use, create a major de~erent to the utilization of such known and established technologies in the processing of agglomerating coals. The potential for the production of clean liquid and gaseous fuels from available coal supplies, e.g, by the hydrocarbonization process, or for the production of synthesis gas by known gasification techniques, has been disadvantaged by uncerta~ntles concerning the overcoming of the agglomerating tendencies of the fresh feed material without resort to the economically undesired approaches of oxidative pretreatment, char recycle or complex process monitoring and regulation as referred to above. Improved, practical methods for overcoming defluidization due to excessive agglomeration of caking carbonaceous feed materials are genuinely needed, therefore, to enable such carbonaceous materials to be effectively employed as a part of the significant efforts to encourage the increased use of available coal supplieY as one aspect of the comprehensive development of available energy sources to satis~y the energy requirement~ of modern, industrial societies .
In the feeding of agglomerating coal to a fluid-bed reaction zone, injection nozzles are commonly employed to inject the feed materlal into the reaction zone at the desired injection velocity to obtain adequate dispersion of the feed material with the non-agglomera-ting particles comprising the fluid-bed. Any suitable, conventionally available injection nozzle c~n generally ~14~6~ 3 be employed for the desired injection purposes. One such nozzle design is that disclosed in the Pfeiffer et al patent, U.S. 2,881,130, with regard to the fluid coking of heavy hydrocarbons. As shown tnerein, the feed material is fed into the nozzle in admixture with dispersion steam through a control conduit having a port or tip 8. Annular passage or shroud 9 surrounds the conduit, with purging steam or shroud gas being passed through passage 9 to keep the tip of the nozzle free of co~e and to permit removal of the nozzle. In the fluid coking field and otherwise, shroud gas velocities of up to as high as 500 ft/sec have been employed. During the injectlon of agglomerating solid carbonaceous feed materials through such nozzles, it is likewise necessary to keep the nozzle tip free of undue particle accumulation that would lead to plugging of the nozzle. It is also highly desirable to employ overall injection conditions such as to avoid or minimize undesired nozzle erosion while, at the same time, assuring adequate dispersion of the agglomerating feed particles within the bed of non-agglomerating particles in the fluid-bed reaction zone In fluid-bed operations employing a feed o fresh agglomerating coal and recycle char, at conventional in~ection velocities, e.g. about 50 ft/sec, at temperatures below the plastic transformation temperature o the fresh feed material, nozzle erosion is generally not a matter of concern. At relatively high ~njection velocities, e.g. over 200 ft/sec, such injection mixtures can, however, cause serious nozzle erosion problems, which must be obviated in order to achieve successful commercial operations on a _9_ ~43569 ~y~d-~

continuous basis.
It will be appreciated that the carrier gas for the fresh carbonaceous feed and the injection nozzle shroud gas both contribute, to some extent, to the overall mechanical energy input available for the dispersion of fresh feed particles in the fluid-bed. It is highly desirable that such factors, as well as the effect of the fluidizing gas and of attrition jets, if employed, be ' understood in a comprehensive manner and utilized ~o enhance the injection of agglomerating feed materials into the fluid-bed and the overall coal converslon operation and to avoid the defluidization due to excessive agglomeration that impairs the commercial utilization of available coal supplies in known and established fluid-bed technologies capable of producing desired liquid and gaseous products.
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 ob~ect of the invention to provide a method of avoiding defluidization in fluid-bed reaction zones employed in coal or other solid carbonaceous con-version operations.
It is another ob~ect of the invention to provide a method for employing caking coals on a continuous basis in a continuous fluid-bed reaction zone wi~hout defluidization and/or undue equipment plugging problems It is a further object of the invention to provide a method for avoiding excessive feed particle agglomera-3569 ',~ y~-3 tion while, at the same time, avoiding undue injection nozzle erosion.
It is a further object of the invention to ~rovide improvements in the hydrocarbonization process for the preparation of fuel products from coal.
It is a further object of the invention to provide a process for enhancing the feasibility of utilizing agglomerating coals in fluid-bed coàl conversion operations.
With these and other objects in mind, the invention is hereinafter described in detail, the novel features thereof being parti~ularly pointed out in the apDended claims, SummarY of the Invention An overall mechanical energy input above the minimum energy level for the particular carbonaceous solid feed particles is supplied to a fluid-bed reaction zone by mean9 o the fluidizing-reagent gas, by the carrier gas for the resh carbonaceous feed, by the shroud gas introduced through the injection nozzle and by attrition jets positioned to break up agglomerates that may form upon introduction o~ the Eeed material to the 1uid-bed. Defluidlzation due to excessive agglomeration is thereby avoided. In various embodiments of the i~lvention, a wide variety oE desirab1e proce~sing alternatives may be employed, the providing of said minimum o~erall energy input assuring against such excessive agglomeration regardless of the effect of individual variations in particle injection conditions or of changes in fresh feed material. Thus, ~ ~43~6~ c~y~o-3 conventional or high velocity feed injection may be employed. Likewise, conventional injection nazzle shroud gas velocities or high energy shroud streams may be employed, together with or in lieu of high feed material injection velocities. At high speed injection velocities, the feed particles may be preheated to a te~perature within the plastic transformation temperature range-to assure minimum injection nozzle erosion without, at the same time, causing undue agglomeration of the feed particles.
Brie Description of the Drawings The invention is hereinafter described with reference to the accompanying drawings in which:
Figure 1 is a schematic diagram illustrating particular embodiments of the fluid-bed coal conversion system in which the process of the invention is employed to prevent defluidization due to excessive agglomeration of the solid carbonaceous eed material;
Figure 2 is a side elevation view of a tapered concentric shroud configuration of an ln;ection nozzle suitable for use in the practice of the invention;
Figure 3 is an end view of the injection nozzle-shroud configuration of Figure 2;
Figure 4 is the end view of an alternate injection nozzle-shroud configuration employing a crimped circular annulus with four filed Elats;
Figure 5 is a side view of an injection nozzle having a shroud containing six shroud gas injection ports; and Figure 6 is an end view of the injection nozzle-shroud configuration of Figure S.

llqr3~69 9 ~ d-~

Detailed Description of the Invention The objects of the in~ntion are accomplished by injecting solid carbonaceous feed particles to a fluid-bed reaction zone under conditions such that the various mechanical energy inputs to the reaction zone exceed the minimum overall energy input required for dispersion of the fresh particles within the bed of non-agglomerating particles and to grind agglomerates that may tend to form upon in;ection of the fresh particles into ~said zone. The minimum overall energy level will vary from one solid car-bonaceous feed material, e.g. one grade of coal, to another.
A.s a result, overall processing conditions satisfactory 12a ~3569 ~ O - 3 for a particular feed material may be unsatisfactory and result in excessive agglomeration when applied to another feed material. Particular novel embodiments of the invention, however, readily supply an overall mechanical energy input such as to assure operability and to prevent defluidization with a variety of available carbonaceous feed materials. In other embodiments, however, assuring that the overall energ~ input is above the minimum input required for the particular feed may conver~ the operation from the range of inherent inoperability, i.e, excessive agglomeration and defluidizatio~, to the operable range in which defluidization due to excessive agglomeration is prevented.
The mechanical energy input to the fluid-bed reaction zone is supplied by the combination, in various respective proportions, of the energy input of the fluidizing-reagent gas in;ected into the fluid-bed, the carrier gas stream for the fresh carbonaceous eed, by the shroud gas introduced through the shroud passage of the feed iniection nozzle and by attrition jets that may be positioned to break up agglomerates that may form upon introduction of the feed material to the fluid-bed. In variou~ embodiment9, a wide variety of desirable processing alternatives may be employed, with the providing of the minimum overall energy input to the reaction zone assuring against excessive agglomeration regardless of the effect of individual variations in particle injection conditions and/or of changes in fresh feed material. The present invention thus precludes the necesslty for employing an oxidative pretreatment or for mixing the fresh solid ~3~69 ~y~-3 carbonaceous material with recycle char as suggested in the art as means for avoiding excessive agglomeration in fluid-bed coal conversion operations.
The invention can be employed in any known fluid-bed coal conversion process technology 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 known fluid-bed coal conversion 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 450C to about 750C, preferably at from about 500C to about 600C, is a hydrogen-rich, oxygen-free gas. Another such process is the carbonization process in which said reagent comprises carbonization product gases and vapors and essentially i~ert carrier gas at reaction temperatures of from about 450C to about 700C. A third such process i5 the gasification proce8s in which solid carbonaceous particles are reacted with steam to ~orm synthesis gas at temperatures generally from about 815C to about 1,110C.
It will be appreciated by those skilled in the art that the invention may advantageously be employed in the practice of other known fluid-bed coal conversion processes, or those subsequently developed, to avoid excessive agglomeration upon the feeding of fresh feed material to a fluid-bed reaction zone.
In the practice of the invention, the fresh feed material may be injected into the fluid-bed reaction ~1~3S69 ~ 9~ 3 zone at a conventional low injection velocity, i.e. in excess of about 20 ft./sec., e.g. from about 30 to about 175 ft./sec. or at high inj ection ~elocities, i.e. in excess of about 200 ft./sec., including velocities in excess of about 400 ft./sec. At such high injection velocities, the feed material can be preheated, as in conventional practice, to a temperature below the plastic transformation temperature of the particles prior to being injected into the reaction zone. It has also been found, contrary to the conventional wisdom of the art, that the feed particl~s may be preheated to a temperature essentially within the plastic transformation temperature range ~or said particles, the relatively hot, fresh particles tending to minimize nozzle erosion at the high velocities employed without, at the same time, causing excessive agglomeration and defluidizing or plugging of the reaction system.
Such preheat temperature will vary depending on the plastic transformation temperature range of the solid carbonaceous feed material employed but will generally be ~ram about 280C to about 400C, commonly in excess of about 325, e.g, from about 240C to about 375C.
At the various in~ection velocity embodiments indica-ted, the shroud gas may be employed in a conventional manner at relatively low shroud gas velocities for purposes o~ assuring that the nozzle tip remains clean and unclogged or, alternately, may be employed to supply a substantial portion o~ the overall energy input to the reaction zone for dispersion of fresh particles within the bed of non-agglomerating particles and for breaking up of any agglomerates that may tend to form upon ~3S69 injection of the fresh particles into the reaction zone.
In various high energy shroud embodiments, ~he shroud gas may be employed at a velocity of at least about 750 ft./sec.
and in sufficient quantity to supply at least half, and in some embodiments at least about 80%, of the overall energy input to the reaction zone for dispersion of the fresh feed particles and for grinding of agglomerates that may tend to form in the reaction zone. For such purposes, the shroud gas ve~ocity may generally range from about 750 to about 5000 ft./sec., preferably from about l,000 to about 3,000 ft./sec. The shroud gas may be~an inert gas, such as nitrogen, or may comprise a gaseous reagent, such as hydrogen, that reacts with the fresh carbonaceous particles in the reaction zone.
In the practice of the invention, it is generally desirable to employ attrition jets suitably positioned to grind agglomerates that may tend to form, thus contributing to the avoidance of defluid~zation resulting from excess particle agglomeration. The solid carbon-aceous Eeed particles may be introduced into the reactionzone in an essentially vertically upwards directlon through inlet nozzle means located substantlally at the bottom of the reaction zone and having an injection point at or near said location for lnjection of the feed particles directly into said reaction zone and into direct contact with the non-agglomerating particles therein. As part of the flexibility of the invention, it should be noted that the feed may be so injected, as for example upwards in the substantially axially central portion of the reactor or in any other convenient direction, 1~435 ~Y~

including downward or sideward, that may be desired in particular embodiments of the invention. Thus, the particles may be introduced into the reaction zone f~om the side thereof in a substantially horizontal, sideward direction.
The particles may further be introduced into the reaction zone through two or more injection points positioned vertically along the side of the reaction zone, with shroud gas being passed, at con~entional or at high . energy le~els, through the shrout passage on the injection nozzle means at each injection point. In other specific embodiments, the carb'onaceous particles may be introduced into the reaction zone through injection points located in essentially opposed positions on the wall of the fluid-bed reaction zone. The fluid-bed reaction zone is conventionally maintained by passing a fluidizing medium through finely-divided solid particles. "Introduction velocity" as used throughout the specification means the velocity of carrying gas. By a high velocity i9 meant a velocity sufficlent to rapidly and uniformly diYperse 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 par-ticles are, however, preferably hot, partially reacted coal particles and char particles that have undergone 3~
56~ o 3 plastic transformation and are situated within the fluid-bed reaction zone at the reaction temperature, e.g.
generally a~ove about 450C. Due to the difference of temperature be~ween the entering coal particles and the reaction zone, heat is ordinarily transferred rapidly from the reaction zone to the entering coal par~icles, accelerating the plastic transformation process and thus the agglomerating tendency of the feed coal for a brief period of time. It has been found that when the pre-heated coal is rapidly introduced in the fluid bed ata high velocity, howeyer,the entering coal particles rapidly and uniformlv 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 above, promotes rapid, turbulent mixing of the entering particles with the particles circulating in the fluid-bed. This prevents their coherence and defluidization by imparting suficient mechanical energy to the reaction zone to break the weaker bonds of the coarser agglomerates, thereby limiting the extent o agglomeration and substan-tially 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 In some embodiments of the invention, the feed particles are preheated to a temperature below their plastic transforma-tion temperature; while in others, they are preheated to ~3569 within said 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 h~ve previously passed through the plastic trans~ormation 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 byparticle withdrawal and deagglomeration. Coal-to-coal bonds are relatively strong whereas coal-to-char bonds are relatively weak, depending on the exten~ 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 injection5 rapid dispersion of the entering coal particles occurs, and the fresh particles thus traverse the plastic transformation temperature range with a minimum number of st~cky 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 in~ected into the fluid-bed reaction zone and devolatilized without defluidization occuring as a result of excessive particle agglomeration Such high speed injection or introduction velocity is not required in other embodiments of the invention.
With the high energy shroud employed, rapid dispersion ~1~;356~ ~7~ -3 of the entering coal particles likewise occurs. The fresh particles th~s traverse the plastic transformation temperature range with, as in the high velocity, high energy application, 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 agglomer~ted particles.
Consequently, agglomerating or caking coals ~an be injected into the fluid-bed reaction zone and devolatiliz~d, in the high energy shroud embodiment, without defluidizatiun occurring as a result df excessive parLicle agglomeration.
While preheating the fresh feed particles to a temperature within the plastic transformation temperature range is of value in minimizing nozzle erosion that might otherwise occur in the high injection velocity embodiments, it is within the scope of the invention to preheat the feed particles to this range at somewhat lower injection velocity conditions depending on the overall energy level conditions employed. While the hot coal ~eature is not required for the prevention of nozzle erosion at conventional in~ection velocities, the hot coal feature provides desirable operating ~lexibility and advantages, as hereinafter indicated, ~hat pertain when the high injection velocity embodiment is used in combination with the high shroud embodiment, and where the high energy shroud is utilized in combination with injection velocities that are at the upper end of the conventional injection velocity range.
This invention is particularly applicable as an improvement in a hydrocarbonization process utilizing a ~1~143~69 ~ -3 dense phase fluid-bed. By the term "hydroc~rbonization"
as employed throughout the specification is meant a pyrolysis or barbonization in a hydrogen-rich atmosphere under such conditions that significant reaction of hydrogen with coal and/or partically 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 hydro-carbonization process employing a dense phase fluid-bed, the particles in the bed are substantially bachmixed, 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 preve~t excessive particle agglomeration will vary for each particular coal or carbonaceous feed material and will also vary depending upon the relative proportions in which the various sources of mechanical energy lnput are utillzed to supply the overall energy input required. In determining the minimum energy requirements of a particular coal, a high injection velocity can be initially employed with t~e injection velocity being incrementally decreased 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 nozæle-tip clean and for ~ ~ 4 ~ 5 ~ ~ ~ Y ~ ~ 3 temperature control pu~poses. In determining the minimum energy required for said coal in embodiments utilizing a high energy shroud, the high energy shroud input level can be incrementally decreased to the point of bed failure.
For such purposes, the bed velocity will conveniently be maintained at a constant -~ate, with the fresh feed injection velocity being maintained at a convenient rate, such as 35-lG0 ft./sec.
The particular injection velocity~preheat tempera-ture-shroud injection conditions employed in the practice of the invention, commonly in conjunction with attrition jets, may be varied, as will be appreciated by those skilled in the art, depending on the overall energy input required and the contributions to said overall energy input of the injection gas, the shroud gas, the bed fluidizing -reagent gas and any attrition jets employed It will be 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 e~ficient overall technical and economic performance. The invention, in the high velocity embodiment in which the coal or other carbonaceous feed material i9 preheated to a temperature within its plastic transformatlon range, minimlzes nozzle erosion 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 ~143569 ~ ~7~ - ~

velocity. In addition, process gas may ~e physically added to the fluidized stream of fresh coal particles at a point beFore the fluidized stream 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 may be trans-ported through the lines in a dense phase flow, a flow ortransport 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 au undesirable expense. However, only a small surface area in the immediate vicinity of the reactor need 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-re~istant surface may preferRbly be employed in this invention as a means for increasing the ~elocity 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 flo~
of coal particles. Suitable wear-resistant sur~ace may be composed of materials such as tungsten carbide, silicon ~ 6 9 ~ Y~o -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 inven-tion will be mainly directed to the use of tungsten carbide as the wear-resistant surface ~f the material that reduced erosion in the lines although any number of other wear-resistant materials can be used successully according to this invention.
An inlet means such as a nozzle which comprises a transfer line having a reduced or constructed cross-sectional area ratio of the nozzle should be sufficiently large so that t~e 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 preerable. This allows for a flnite distance which the coal particles and/or vaporizable recycle oil require for acceleration to the ~elocity approaching that of the carrying gas,.
The feed particles may be introduced into the reaction zone in any convenient direction, e.g. upward, downward, sideways or otherwise. For example, the ~eed 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 11~35~9 of the reaction zone. In certain embodiments, a multipli-city 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 the 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 bottom. The coal particles are introduced at a velocity sufficient to mix the fresh coal, in some embodiments having a preheat temperature below the plastic ~ransformation-temperature, rapidly with non-agglomeratlng particles such as partially reacted coal and char particles in the reaction zone at the reaction temperature thereby substantia1ly preventing agglomeration of the fluid-bed.
In a ~ertical 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 concentrlc 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 a~ially 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.

-2~-5~9 ~7~

Advantages of introducing the 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 down-flow 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 o the reactor inter-sects the base o the reactor.
The reactlon temperature within the 1uid-bed reaction zone is generally maintained above about 450C for known coal conversion proce~ses, with such temperatures being generally from about 500C to about 750C, commonly ~14356~ ~Y70 - 3 from about 500C to about 600C. The invention utilizes, in a variety of processing alternatives lending considerable oper~ting flexibility to the overall coal conversion opera-tion, the various sources of mechanical energy input to the fluid-bed reaction zone to supply sufficient overall mechan~cal energy input to exceed the minimum level need for dispersion of the particular feed material and to grind agglomerates that may tend to form upon injection of the particular feed particles to the reaction zone. The discovery of the exis-tence o such a mlnimum energy level for particular feedmaterials and of the ability to achieve such minimum by novel modifications of conventional operating techniques overcomes the processing difficulties that have heretofore hindered the use of known, commercially-available, fluid-bed coal conversion techniques. The above-indicated processing flexibility enables those skilled in the art to employ the most economic processing alternatives for a given coal conversion operation with a particular fresh carbonaceous feed, without inadvertantly incurring an undue risk of excessive agglomeration and defluidization. For this purpose, the invention utilizes the energy input of the fluidizing-reagent gas, the fresh feed carrier gas, the shroud gaspa~sing through the feed ln;ection nozzles and attrition ~ets, if employed, to supply mechanical energy to the reaction zone in excess of sait minimum level required for a particular feed material. When employed in excess of said minimum energy level, the mechanical energy input is suf~icient to break down the weaker bonds of the coarser agglomerates that may form, thereby substantially preventing excess agglomera-tion and defluidization. In some embodiments, conventional low injection velocities, i.e. in excess of about 20 ft./sec., e.g. from about 35 to about 175 ft./sec., typically about 50 to about 100 ft./sec., may be employed, together with a high energy shroud or the use of attrition jets to furnish 569 ~;7y~d-_~

a substantial portion of the overall energy required. In other embodiments, high speed injection of the fresh particles, iOeO at velocities in excess of about 200 ft /secO, preferably above about 400 ft./secO~ may be employed, with a conventional shroud gas input or with a high energy shroud, and with various desired bed fluidization conditions and the use of attrition jets as required. While injection nozzle erosion is not generally a major operating problem at low injection velocities, it may become such at higher injection velocities, It is within the scope of the invention to preheat the feed particles in a conventional manner to a temperature below the pLastic transformation temperature range or, in a particularly unique embodiment~ to preheat the particles to a temperature within the plastic transformation temperature range of the particles. In this embodiment, the preheated particles are fed rapidly and directly into the reaction zone, generally at high injection velocities, so as to avoid undue agglomeration The particles preheated to this temperature range have been found to possess a desirable lubricity such as to minimize noæzle erosion without, at the same time, causing undue agglomeration leading to defluidization In the conventional preheating operation, the coal or other carbon-aceous feed particles are preheated to a temperature Less than about 300C to assure that khe particles are not heated to within their plastic transformation temperature range until they are rapidly dispersed within the fluid-bed reaction zone, In either embodiment, the feed particles can be preheated by known techniques, such as in a fluid-1~43S69 7y~ 3 bed heating zone or in suitable means for accomplishingdense phase heating, prior to being introduced into the fluid-bed reaction zone.
In particular embodiments, a high energy shrolld is used to supply a substantial portion of the overall mechanical energy input to the reaction zone for dispersion of the fresh feed particles and for breaking up of agglomerates. The shroud gas, which may be an inert gas, such as nitrogen, or a gaseous reagent for the fresh carbonaceous feed particles, e.g. hydrogen is advantageously supplied in sufficient quantities and at such velocities as to advantageously supply at least half of said energy input to the reaction zone, preferably at least about 80% thereof.
For this purpose, shroud gas is passed through the injection nozzle shroud passage at a velocity in excess of about 750 ft./sec. up to about 5,000 ft./sec., preferably in the range of from about 1,000 to about 3,000 ft./secO Any convenient, commercially available injection nozzle, such as that illustrated in Figure 3 of U.S. 2,881, 130, may be employed ln the practice of the invention. It is within the scope of the invention to employ, as an alternate to annular passage and therein disclosed and illustrated, a number of shroud passflges positioned around the periphery of the fresh feed injection conduit. It is particularly advantageous to pass shroud gas into the reaction zone tangentially to the fresh feed injection conduit to enhance dispersion of the shro-ld gas and its dispersion of the fresh feed particles within the bed of non-agglomerating solid carbonaceous par-ticles.

~ ~ 4 3 ~6g ~ 3 The fluidizing-reagent gas is employed to maintain a bed of non-agglomerating particles into which the fresh feed is uniformly dispersed. Superficial gas velocities, i.e. bed velocities, of from about 105 to about 4 ft./sec.
or more are commonly employed, with various levels of turbu-lent or fast fluid bed operation having been described in the art. In general, the fluidizing gas is the least ef~ieient means of imparting the necessary mechanical energy to the fluid bed for the purposes of preventing excessive agglomeration~ Attrition jets are generally the next least ef~icient, with the energy supplied by a high ener~y shroud being a preferred means of supplying such energy and with the mechanical energy of the carrier gas for the feed material being the most efficient means of supplying such mechanical energy. As those skilled in the art will appreciate, the relatively high gas/coal ratio of high injection velocity embodiments would be economically disadvantageous unless compensated for by the processing flexibility achievabLe in the practice of the present invention~ It has been found, however, that the high in~ection veloclty embodiments, including those in which the coal is preheated to the pLastic transformation tempera-ture range of the particles contrary to conventional practice, are suitable in achieving the overall heat and material balance limitations for satisfactory commercial operations.
Attrition jets are known in the art and may be suitably placed to brea~ up larger slzed agglomerates as described in fluid coking, for example, in U.S. Patent No.
2,881,130. For purposes of the present invention, it is 3569 ~a-3 convenient to place attrition jets in the bottom or boot of the reactor below the fresh feed injection nozzle, which may extend upward a ~oot or two into the reactor in those embodiments in which the feed is injected vertically upward into the reaction zone. Inert gas or a reagent for the fresh feed may be used as the attrition jet gas, as in the case of the gas passing through the injection nozzle shroud passage.
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 ~eet 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 uni~ormly 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-20 bed is not prevented. In order to substant~ally preventagglomeration of the 1uid-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 feet per second, and preferably more than about 400 feet per second, corrssponding to sn energy-to-coal ratio of at least about lO x 10-4, preferably at least about 40 x 10 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 11~3569 ~?y~o ~

of the feed mixture) to the coal feed ~ate. When a lower injection velocity, for example, about 100 feet per second is used, without other modifications from conventional prac~ice, agglomeration of the fluid-bed is not prevented.
By passing shroud gas through the shroud passage or passages on the feed injection nozzle means at a velocity in excess of about 750 ft./sec. with the shroud gas being employed in sufficient quantity to supply a substantial portion, as indicated above, of the overall energy input to the reaction zone for dispersion of the fresh particles within the bed of non-agglomerating particles and for the breaking up of any agglomerates that may tend to form upon inject~n of the fresh carbonaceous particles into the reaction zone, defluidization due to excessive agglomeration can be prevented at lower feed injection velocities. The energy-to-coal ratio of the high energy shroud embodiment will ordinarily be higher than that required for the high injection velocity alternative because less gas is a.vailable to in;ect into the reaction zone in such embodimen~s. The energy-to-coal ratio in the practice oE the hlgh energy shroud embodiment will generally be at least about 40 x 10 4, preferably at least about 100 x 10 4, horsepower-hours per pound of coal introduced, The energy-to-coal ratio, as referred to in this embodiment, refers to the ratio of the kinetic horsepower (in the shroud gas jet as calculated by the adiabatic expansion of the shroud gas jet) to the coal feed rate. As indicated above, attrition jets and the fluidizing gas are less efficient means for imparting the necessary mechanical energy to the fluid bed for purposes of dispersion a~ the prevention of excessive ~356~ ~C/~

agglomeration. It will be appreciated that the energy-to-coal ratio required in embodiments in which such less efficient means were employed as principal sources of the overall mechanical energy input level required for a particular feed material will be higher than indicated above with respect to the more efficient high energy shroud embodiment or the most efficient high velocity, high energy feed injection embodiment. "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 con~ersion 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 æo~le 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 lmproved 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 o coal particles may be passed through a preheating zone before entering a 1uid-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 450C where the desired reactions can occur, The improvement according to this invention comprises introducing the preheated fluidized coal particles into the 1uid-bed, through the bottom of a hydro-carbonization 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, partislly 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 hydro-carbonization zone in a vertically upwards direction asdegcribed hereinabove at a ~elocity 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:

~1~3569 ~Y~ 3 TABL~ A. Cl~-~ltlc~tlon Or Co~1~ Oy Ba~ ~
(Letend F.C tl~ed c~rboD; V.M ~ol~tlle ~te~r; B t u Brltioh eber~l urlt-) Cl-6~ Cro~P Ll~ito Or rlsed c~rboD
or 3 t u ~-b rree b~
1. Met~-~ntbr~clte Dry F C , 93S or ~or~
(dr~ C ~ , 2S or le~a~
2. Arthr~clte Dry F C 925 or oor~
rd lea th-n 985 (dry ~.~ , ôS or le~ a~d I Anthr-clte or- th-r 2S)

3 Se~lunthruclte b Dry F C , 865 or oore l ~nd le~ tb~n 92S (dry I Y.M., 14S or leoe ~nd ore tb~D 8S) 1 LoY-~ol-ell- bltuol- Dry F C S85 or or~
noua co-l u~d le-s eh~n 36S (dry V.~ , 22, or le~ Dd ore tb~D l~S) 2. Metlum-~ol~tl-e Oltu- Dry F C 69S or uor~
~lnoun co~1 c~ le-; tb~n ~8S (dry V M , 31S or leo~
I oore tbun 22S) Il Bltu~lDouo 3 E16h--ol-tllo 6 bltu- I Dry F.C , leo~ ehoD 69S
~inouo co~l I (dry V ~ , ~oro tb~D 31S) Bl~h--ol~tllc B bltu- Mol-tC B t.u., 13,000 or lnoue oo-l I uore ~Dd leoe tb~n l~,OOOe U 6h--ol-ell- C bltu- I Yol~t 3 t u , 11,000 or ________________ ulnouo co~lr oore ~DC. ~ th~n 13 00^
1 8ub-bltu~lnouo ~ co~l Molot B t.u., 11,000 or uor- DDd lo-- tb~D 13,000-III 8ub- 2 8ub-bltu~lnouo B co~l Moloe D t u., 9,500 or uoro bieu~lnoue ~nd lee- t~D ll,OOQ~
3 Sub-bltu~lr~ouo C co-1 Molct B t u , B,300 or ore ________________ _ _ _ nd 1--- th~n 9,500e 1 Lle-rlt- Molet B t u , lo~- tb~c 1~ Llgnltlc ô,300 2, Brovn co~1 Mol~t B ~ u , loo- tb-n _ 3,300 - ~hl~ cl~e-l lc-tlon do-- Dot luclu~ t rOY co~lc thct b~o unu-u-l pby~lc~l ~nd cho-lc~l cropertloo ~nd tb~t coo- vl~bln ~he l~lt~
o~ tl~-d c~rboD or 8 t u. Or th- bl3h--ol-tlle bStu~lnou~ ~Dd eub-bltuul~ou~ runL~ All or tb~ co-1~ elth-r cont-Ln 1~-- tb~D 48, ~olOeur- ~nd eh tr-e rl~ed c~rOon or h-Yo oor- tb~D 15,500 oL~, och tr-o B t u b - ~t ~elo.-r-tlr~, elnnelry ln lov rolntLlo ~roup Or ~b~ bltu~lnou~
cl~
c - Molet B t u. ror-r- to co~l cont~lnlD6 le- n-tur~l bed col~turo but Doe 1DC1U~1D6 1-101~ ~e-r on th- ~urt-c~ oS eb~ co~l - ~t 1- roco6nl~od th~t thoro r-r 0- nonc-~ln6 ~rlotL-o 1D o~ch ~roup ot thc b~tu~lnouo cluoc o - Co~l~ h-~lDt 69S or oro tl~-d c~rOon on the ~rJ, uln~r~ ttor-troe 0--1- eh~11 b- cl~-clrl-d ~ecordlDg to tl~od c rbon, r-~urd-l-cc Or B.t.u.
r - s~-r. r- thro- ~-ri-tl-- Or co~l 1D the bl~h-~oluel1- C bltu lnoue co~l ~roup, u--ely, ~urleey 1, et~louer~elD~ ~Dd DoD_ve~th-rlDt;
rloey 2, ~10-er~tlDt uDd ve~th-rlng; t rloty 3, noD-g~lou-rttln6 ODd DOD_VO--th~rlDg.
60urce A.6 S.~. D3a8-38 (ror. 1).

~43569 ~Y~a- 3 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 pre-treatment, the use of a highly agglomerating coal such asPittsburgh Seam Coal in a hydrocarbonization process presents the problem of agglomeration occurring in the fluid-bed. Houever, 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 a~glomerating in a hydrogen-containing atmosphere, These pretreatment steps include, for example, but are not limited to, chemical pre-treatment 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 ollowing 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 Figure 1 illustrates coal supply vessels 10 and 16, a coal feeder 22, a preheater 30 and a reactor vessel 40.

~4356~ Cj- 3 Lines are provided for conveying finely divided coal through the vessels in sequence. A line 27 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 produce or for recycleO 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 ~eed coal may contain adsorbed water, it is preferably free of surface moisture. Coal particles meeting these conditions are herein reerred to as "1uidizable." Any such adsorbed water will be vaporized during preheat. Moreover, any such adsorbed water mu~st be incLuded as part of the inert carrying gas and must not be ln 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 ~hich fluidized ~43~69 ~7 Y~ -3 coal can be pressurized with process gas or o~her desired fluidization gases.
Operation of vessels 10, 16, and 22 can be illustrated by describing a typical cycle. With val~es 14 and 17 closed, lock-hopper 16 is filled to a prede~ermined 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 i9 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 1uidized feeder vessel 22 through open valve 17 and line 20. The cycle abou~ loc~-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 2~ 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 slnce they do not Eorm the inventlve steps of this process.
In fluidizet feeder 2~, 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. Alternate-ly, 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, nLtrogen, hydrogen, steam and the like. However, it is preferable, in general, to use reaction process gas or recycle product gas.

~4356~ d ~ 3 Coal preheater 30 is a means to ra~idly preheat, when desirable, the finely divided coal particles, under fluidized conditionq, to a temperature below the minimum temperature for softening or significant reaction ra~ge, in the substantial absence of oxygen, The maximum allowable temperature of heating is generally in the range of from about 325C to about 400C depending on the feed material employed. 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 tempera-ture by any convenient means of indirect heat egchange, e.g., by means of radiant heat or a hot flue gas such as depicted in Figure 1 as entering the bottom of heater 30 through line 28 and exiting at the top of the heater 30 through line 32.
Preheated ~luidized coal particles exit the preheater 30 through line 34 and enter at or near the bottom of the reactor ves~el 40 substantially near the center of the bottom, In this illustrative 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 ~y addition o~ an accelerating gas and/or along a constricted path oE confined cross-~ection, A nozzle, narrow inlet port, tapered channel or any inlet means which narrows, constricts or necks down the cross-9ectional area of the passageway to the inlet where the fluidized coal particles enter the reactor may be used to accelerate the 1uidized stream of particles to the desired velocity. The stream of preheated, ~143S69 C~4 ~ 3 fluidizable coal particles is introduced into the central upflow zone of the fluid-bed within the reaction vessel at ~he 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 ~pward~ 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 iniection 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 immédiately and directly strike the walls of the reactor vessel, a result which could lead to unnecessary and unde~irable agglomeration.
Only one inlet each for entry o the preheated coal p~rticles and the recycle oil is shown in Figure 1.
These inlets may also represent a multiplicity o~ inlets for ease of operation of this process. A multipliclty of inlets may be desirable, for example, where the reactor i9 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 ~356~ 9490-3-C

in an essentially vertically upwards direction, the inlets si~uated 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 temper-ature above about 450 or 500C.
Char from reactor vessel 40 is continuously re-moved 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 ir.volved. 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 hydrocarbonl~er in a hydrocarbonization process.
As disclosed herein, advantages may be obtained in other embodiments of the invention by passing the pre-heated particles to the Eluid-bed reaction zone at relatlvely low injection velocities while employing a high energy shroud gas together with attritlon jets to prevent excessive agglomeration and defluidization. Preheated particles in line 34 of the drawin~, for example, are passed rapidly and directly into the reaction zone from the bottom thereof through injection nozzle 46 which is shown extending slightly ~ ~43569 9~ 7~ -3 upward into the reaction zone. Nozzle 46 is sho~n with an annular shroud passage 48 through ~hich a shroud gas may be passed at a high velocity and in such quantities as to furnish a substantial portion of the overall energy input to prevent excessive agglomeration of the feed particles.
It will be appreciated that t~.e fresh feed particles can be introduced into reactor 40 in any other direction, as by injection from the side thereof in a substantially horizontal, sideward direction through one of a series of injection points positioned along the side of reactor 40. In particular embodiments, the injection points may be located in essentially opposed positions on the wall of reactor 40 for ~urther 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 instructed with a lower reaction zone, an enlarged upper zone and a cone-like transitlon zone, the upper zone having a lower bed velocity facilitating separa-tion of gaseous materials from the bed and minimizing undesired carry-over o fines in the ga~eous effluent streams.
It will be further understood that the feed inlet nozzle means 46 may ~e positioned so that the in;ection polnt is substantially at the wall of the reaction vessel, e.g. at the bottom thereof, but may extend somewhat into said zone In the upward inj~ction embodiments, for example, the injection nozzle 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. 2,709, 675 which relates to low speed coal injection, preferably in conjunction with a draft-tube positioned 1~3569 9490-3-5 within the fluid-bed reaction zone. The high energy shroud gas passing through shroud passage 48 supplies a substantial portion of the overall mechanical energy employed to break up agglomerates of the feed particles.
Attrition jets are also employed, as required, to break up agglomerates, supplementing the energy supplied by the injectio~ gas, by the fluidizing gas and by the high energy shroud. In the embodiment illustrated in the drawing, for example, attrition jets represented generally by the numeral 50, may be conveniently positioned beneath the feed injection point so as to break up larger agglomerates that may tend to settle in the boot portion at the bottom of the reaction zone.
Further advantages unappreciated heretofore in the art are obtained by preheating fluidized coal particles in preheater 30 to a temperature essentially with 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 on 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 tendin~ to minimize undesired nozzle erosion while the rapid and direct injection of the particles into the reaction zone precludes excessive agglomeration of particles and resultant defluidization. As ntoed above, the feed material may be passed through line 34 for downward or other injection into reactor 40. In particular embodiments ~43569 ~Y~ - 3 shroud gas may be passed through shroud passage 48 in a conventional manner to m~intain the nozzle tip cleAn and free of clogging problems, and to avoid overheating of the fresh coal particles.
Among the various injection nozzle shroud configura-tions employed in the practice of illustrative examples of the invention have been (1) a concentric annulus formed by a 0.25" outside diameter feed tube and concentric tube walls;
(2) a tapered concentric annulus; (3) a crimped circular annulus with four filed flats; and (4) a shroud containing six 0.0135" ports positioned at 30 to the coal injection axis. In the concentric annulus configuration, a 3/8"
diameter outside tube has been employed, with the injection nozzle feed tube tapering to a 0.082" injection opening wit the uniorm diameter shroud passage having an opening of 0.027", with three guide members employed to position the feed tube within the tube walls. The tapered, concentric annulus configuration, illustrated in Figures 2 and 3 of the drawings, was prepared with a 0.082" inside diameter port or injection opening 52 in 0.25" outside diameter feed tube 54. Tapered shroud portion 56 wlth an annulus outside diameter of 0.208" and a 0.003" planned clearance extends from an initial tube wall portion 58 having a 3/8" outside diameter and projects about 0.10" beyond the tip of in;ection port 52, which is centered in the shroud by jamming against six 0.018" outside diameter nickel wires 60 hexagonally spaced in the annulus The crimped circular annulus illustrated in Figure

4 was prepared by filing four shallow flats 62, 0.11" in width on 0~25" outside diameter feed tip 52 as shown in ~3S69 ~ 3 Figure 2, that was then press fitted into a tapered shroud portion 56.
Figures 5 and 6 illustrate a shroud configuration in which a nozzle tip 64 was built with six 0.0135" inside diameter holes 66 surrounding the 0.082" feed port 68 at said nozzle tip, The six shroud holes were oriented 30 to the axis of the coal feed nozzle. A 1/4" outside diameter feed tube 70 and a concentric 3/8" outside diameter tube wall 72 were employed in the preparation of the nozzle.
It will be understood, however, that the described shroud configurations ~re illustrative only, and various other configurations capable of supplying shroud gas at the velocity and energy levels desired can be employed in the practice of the invention.
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 schematLcally in the drawings, comprised two coal feed lock-hoppers ~10,16) connected in parallel to a fluidlzed Eeeder 22, ~ preheater 30 and reactor 40. The entire coal conveying line was constructed of 3/8-inch l.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 height of 12 feet. The reactor 40 had an ll-inch I.D.
fluid-bed, a bed depth of 17-1/2 feet an outside cross-sectional area of 0~66 sq. ft.

~356~ Y ~ - 3 The average veloc~ty 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 2~ hydrocarbonization are shown in Table I below:

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::3 143565

5~Y'~

TABLE II-LAKE DE SMET COAL, WYOMING, SUBBITUMINOUS C (ANALYSIS) Moisture and Ash Free BasisWeight 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 235C) 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 re-cycle oil, an oil preheater to preheat the oil prlor to in~ection into the reactor.
The main hydrogen stream to the reactor was split into two roughly equal ~treams, each of which was preheated to 300C to 350C. The heavy recycle oil was pumped into one of these hydrogen streams and in~ected into the reactor through a l/4-inch diameter tungsten carbide nozzle at a 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 ~hrough 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.

~3569 8~
~O -3 TABLE III

Run; ~ 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 - H2, Inlet Velocity 16C ft./sec. 160 ft./sec.
Oil - H2, 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 in;ecting 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 constru,cted from a 3-inch diameter by 4-foot high schedule 80 carbon steel pipe; a reactor was made of l-inch I.D. by 9-inch high stainless steel tube having a l/4-inch wall thickness and an expanded head 4-inches high and 2 inches I.D.; solids overflow line construc-ted of l/2-inch Schedule 40 pipe; a vapor line constructed from 3/8-inch O.D. stainless steel tubing; and a solids feeder, Two liquid feed pumps, Lapp Microflow PulsaEeeders were used, one to feed the liquid being investiOated and the ot~r to feed water for steam generation. Electrically heated liquid and water vaporizers and superheaters con-structed of l/4-inch O.D. stainless steel tubing were installed between the feed pumps and the feed injection nozzle to the reactor. Thermo-couples located 3,6,8 and ll-inches from the bottom of the reactor were installed in :~' ~3~69 9.f9,~- 3 a l/4-inch o.S. thermowell placed axially in the cen~er of the reactor. The lower three thermowell were in the fluidized bed while the upper thermocouple was in the vapor space above the bed.
In operation, tars boiling about 235C obtained from hydrocarbonization of Lake de Smet Coal were employed as the feedstock to the reaction zone for conversion to oils ~oiling below 230C. The tars were distilled from the whole liquid product obtained from the hydrocarbonization into various dist~llation fractions and a blend of these distillation fractions used in this example had a nominal atmospheric temperature range for 75% of the tar between 235C and 460C. The remaining 25% boiled above 460C.
The solids feed hopper was filled with Lake de Smet hydrocarbonization char as described hereinabove. The water and tar feed reservoirs were filled and hcated to operating temperature. During the heat up period, a pre-deter~ined flow of hydrogen passed through the empty reactor. As soon as operating conditions were approached, the char ~eed and water feed (superheated steam by the time it entered the reactor through the in~ection 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 Eeed this tar stream at velocities of 100, 200 and 300 feet per second resulted in rapid agglomeration of the fluldized reactor bed. A 26-gauge h-,~podermic needle used was to achieve a 400 feet per second inJection velocity of the wnole tar feed Using this inlet veloci~y for the whole feed, co~ing up of the fluidized bed within the reactor was prevented under the following operating conditions contained in Table IV.

~143569 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 Veloci~y 1.33 sec.
Char Feed 250 glhr.
Oil Feed Rate 2 ml/min.
Water (as steam) Feed 3 ml/min.
10 Hydrogen Flow to Reactor 35 S~FH
Moles Hydrogen/Moles Oil 45/1 Temperature 650C
Su~erficlal Linear Velocity of Hydrogen 0.5 ft./sec.
Time of Run 5 hrs.
Eluidizing 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 540C
to obtain liquid products, gaseous fuel and dry char.
Pittsbur7h No. 8 seam coal is a highly swelling, agglomerat-ing, high volatile A bituminoua coal. Nominal residence time of the coal and the product char in the reactor bed is 15 minute~. When the coal i~ introduced into the reactor bed with recycled product gas at a coal and ga~
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 fluid-bed of the reactor at injection velocities of 200, 300 and 400 feet per second, respectively, a fluid-bed at a ~3S69 =~

reaction temperature between about 500C and about 700C 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 stic~y, 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. Patent 3,171,369, 1000 pounds per hour of fresh Pittsburgh No. 8 seam coal, -60 mesh, is gasified at a temperature between about 816C and about 1000C with steam, Heat is provided by circulation to the gasifier of about 12,000 pounds per hour of agglomerated ash particles rom a char ~ired, fluid-bed combustor. When the fresh coal is injected into the fl~id-bed of ash and partially reacted coal, at a velocity o~ 20 feet per second with steam, partial agglomeration occurs. Large aggregates oE
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 second5 dis-persion within the fluid-bed is excellent. No significant agglomeration occurs and separation of the fine char formed 69 3~
~l/ 7~ - 3 and the larger denser particles of agglomerated ash is readily accomplished~ The int~oduction of the fresh coal into the fluidized, generally descending bed of hot agglomer-ated ash, at a velocity of 400 feet per second, occurs at a point near the bottom of the bed, but somewhat above t~e bottom to avoid carry-down of coal or char by the cycling ash. Injection is in a generally vertical and upward direction.
This promotes great turbulence of ash, coal and char near the points cf introduction, which disperses the coal throughou~ the bed and effectively prevents agglomeration.

EXAMPLE Vl The advantages obtainable in the practice of the invention were demonstrated by introducing Illinois No. 6 coal, without recycle char and without pretreatment oxidation, upwardly into a fluid-bed hydrocarbonization reaction zone at an injection velocity oE 140 ft./sec., said coal h~ving been preheated to a carrier gas/coal mixture temperature of 340-350C, The inltial softening point o~ the coal was about 325-350C. The coal particles, which were 60-70V/o -200 mesh, were ~ed to the reaction zone at a feed rate of 41-44 lb. oE coal/hr, The injection gas/coal ratio was 6 scf (9tandard cubic feet) o gas per pound oE coal. Gas was passed through the shroud passage of the in~ection nozzle at a velocity that was decreased sequentiall~ from 1950 to 1570 ft./sec., corresponding to a kinetic energy/coal ratio that was decreased from 79 to 52-x 10 hp-hr./lb.
of coal over the course of the run. The shroud passage comprised six 0.~135" ports positioned 30 to the coal axis.
The injection nozzle was located 6 1/2" above the grid at the bottom portion of the 60" reaction zone. Attrition jets 35~ 3 positioned in the bottom portion of the reaction zone, below the feed injection point, were employed at an attrition gas velocity of 485-670 ft./sec., corresponding to a kinetic energy to coal ratio for the attrition jets of 22-56 x 10-4 hp.-hr./lb. of coal. The bed velocity at the bottom of the 3" diameter reaction zone varied from about 2.3 to about 2.5 ft./sec., the bed density at this portion of the zone varying from about 6.2 to about 7.7 lb./ft3, Three inches from the top of said zone, the bed velocity varied from about 2.7 to about 2.9 ft./sec., with the bed density being in the range of 5.6 to 6.4 ~b./ft. The reactor employed had an enlarged, 6" diam~ter upper zone and a cone-like transition zone, with the 41" upper zone having a lower bed velocity to facilitate separation of gases from solids without excessive carry-over of fines. The bed velocity in said upper zone ranged from 0069 to 0.85 ft.l~ec., With the bed density being 9.3-10 lbs./ft3. No defluidi~ation or bed failure was encountered during the run. Rapid dispersion of the feed particles with the char in the fluid-bed reactlon zone, together with deagglomeration due to the mechanical or kinetic energy supplied to the reaction zone in excess of the minimum energy level required for dispersion and the breaking-up of agglomerates, served to maintain the average bed size in a range suitable for fluidization. Such energy was supplied by the carrier gas for the fresh coal feed at a moderate injection ~elocity, by the high energy shroud, by the attr~tion jets and by the fluidizing-reagent gas, i e. hydrogen, employed for the hydrocarbonization reaction carried out in the fluid-bed reaction zone. The overall kinetic energy input was sufficient, therefore, to avoid 1~43569 ~ 3 excessive agglomeration and to control particle size within the reaction zone to a range that could be fluidizedO

EXAMPLE VII
In operations utilizing the reactor system of Example VI above, the indicated 100~/o Illinois No, 6 coal was injected into the hydrocarbonization reactor at an initial velocity of about 170 ft./sec, at a gas plus coal injection temperature of 335C which was at or near the initial softening point of the coal, which ranges f~ m about 325~C to about 350C, The injection nozzle in this run was located 20" above the grid at the bottom portion of the reaction ~ne, The coal feed rate was 31-33 lb,/hr., with the injection gas/coal feed rate being 9,5 scf of gas per pound of coal, The attrition jets were employed at attrition gas velocities of 400-~30 ft./sec., correspon-ding to an attrition jet kinetic energy of about 16-21 x 10 4 hp./hr./lb. of coal, Injection nozzle shroud gas was employed at a shroud gas velocity of 2600-2800 ft./sec,, corresponding to a shroud kinetic energy of 170-200 hp/hr./lb, of coal, The bed velocity at the bottom of the fluid-bed reaction zone was 2,9 ft,/sec,, with a bed density of 7.8-8O9 lb/t3, ~t a point 3" from the top of said zone, the bed velocity was 3,5 ft,/sec,, wl~h the bed density At this point ranging from 10 to 11 lb,/ft , In the enlarged upper zone, bed velocity was reduced to 0,92 ft./sec, at a bed density of 9-10 lb,/ft , Excessive agglomeration was avoided under such conditions, When, after operating for about 1 1/2 hrs, the injection velocity was incrementally reduced to 130 ft,/sec, and then down to 95 ft,/sec,, an agglomerate plug formed blocking the bed entirely within 13 minutes at the low injection velocity. Subsequently, the bed was operated at a coal feed rate of 48 lb./hr, over a period of 46 minutes. The injection velocity was reduced from 310 to 220 ft./sec. during this period resulting in a 52 lb./hr. peak instantaneous coal feed rate prior to p~ugging. Attrition j ets were employed at 760 ft./sec. with a shroud gas velocity of 2800 ft./sec. during this latter period. The kinetic energy input of the injection gas was 3.7 x 10 4 hp-hr./lb. of coal; of the attrition jets, 74 x 10 4 hp-hr,/Lb. of coal; and of the shroud gas 118 x 10-4 hp-hr./lb. of coal for a total of such inputs of 196 x 10 4 hp-hr./lb. of coal~ Bed velocities were 3.2, 3.9 and 1.0 ft./sec. at the bottom, 3" from the top and in the enlarged upper zone, respectively, with the bed densities at said points being 8.8, 4.5 and 5.9 lb./ft3. In this example, as in Example VI, the high energy shroud was employed to supply a substantial portion of the overall kinetic energy input to the reaction zone to which fresh feed was intro-duced at moderate and at relativeLy high injection velocities.
An embodiment of the inventlon in which high injection 20 velocity was employed in conjunction with said high energy shroud i9 described in Example VIII below.

EX~IPI.E VIlI
The reactor system of Example Vl was employed in operations utilizing Pittsburg No. 8 coal that was in;ected upwardly into the 1uid-bed reaction zone through an injection nozzle located 20" above the grid at the bottom of the reaction zone. The injection velocity was 380-395 ft./sec.
at a gas plus coal inj ection temperature of 350-400C. The coal feed rate was 21-28 lb. of coal per hour, with the injection gas/coal feed rate being 24 to 31 scf of gas/lb.
of coal. The attrition jets were employed at a velocity 1143569 ~y70- ~

of 720-760 ft./sec. and an attrition kinetic energy of 12-23 x 10 4 hp-hr./lb. of coal. Injection nozzle shroud gas was employed at a velocity of 2500 ft./sec. and a shroud gas kinetic energy of from 170 to 240 x 10 4 hp-hr./
lb. of coal. The bed velocity at the bottom of the reaction zone was 3.0-3.2 ft./sec.; with a bed density of 16.7-19.6 lb./ft3. At a point 3" from the top of the zone, the bed velocity was 3.9-4.0 ft./sec. with the bed density ranging from 10 to 14 l~./ft . In the enlarged upper zone, bed velocity was reduced to 1 ft./sec. with the bed density varying from about 11 to 17 lb./ft3. The kinetic energy of the high velocity injection gas was ~ hp-hr./lb. of coal.
Excessive agglomeration was avoided at the high injection velocity, high energy shroud, attrition jet operating con-ditions employed, and no noticeable erosion of the injection nozzle occurred. The overall klnetic energy input to the reaction sy3tem was adequate, therefore, to maintain the average bed size in a range suitable for fluidization, creat-ing a rapid dispersion of the fresh feed particle~ with the char in the fluid-bed reaction zone and breaking up agglomer-ates at an energy level adequate for the successful operation of the fluid-bed reaction zone without defluidization due to excessive agglomeration.
It should be noted that excessive agglomeration and deEluid-iza~ion are not prevented simply by a high fresh feed ihj ec-tion velocity or by a high shroud gas velocity, but by the injection of carrier gas, and fresh coal or other carbonaceous particles, and/or said shroud gas at such quantities, or loading levels, as to provide sufficient mechanical or kinetic energy to assure that excessive agglomeration and resulting defluidization are prevented. As is disclosed herein, the ,569 ~ 0- 3 minimum energy level required ~or dispersion of the particular feed and to break-up agglomerates can readily be determined for any particular feed and for particular applications in which the more efficient high injection velocity and/or high energy shroud embodiments are preferred on the basis of overall design considerations.
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 provides for the imparting of sufficient mechanical energy to the reaction zone, by the high velocity injection gas stream or by the high energy shroud, to break up the coarser agglomerates that may form and to rapidly and uniformly disperse the fresh feed particles within ~he fluid bed of non-agglomerating particles within the reaction zone, In embodiments incorporating the high injection velocity-hot coal feature, the invention enables nozzle erosion to be minimized ~o as to avoid premature shutdown res~lting from excessive erosion, The unique use of preheat temperatures within the plastic tran9formation range can thus be advantageously employed ln conjunction with high velocity coal injection, without the necessity for admixture of the fresh coal with recycle char and/or oxidation pretreatment, at kinetic energy levels such as to substantially prevent defluidization in the reaction zone despite ~he caking tendencies of the feed material and the preheating thereof to their plastic transformation temperature range. Sufficient mechanical energy is thus imparted to the reaction zone, by the high velocity injection gas and/or the high energy shroud gas, to break up the coarser agglomerates that may form and to rapidly and uniformly disperse the ~resh feed ~356~ ~y90-3 particles within the fluid bed of non-agglomerating particles within the reaction zone.
The invention, in its various embodiments, provides highly desirable flexibility and operating alternatives.
The high energy shroud embodiment avoids the economic disadvantages and nozzle erosion concerns normally associated with the high injection velocity approach to avoiding excessive particle agglomeration. The high in;ection velocity/hot coal embodiment overcomes the economic disad-van~ages of high gas/coal ratios associated with highinjection 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 transfor-mation range, o 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 dispensible, high velocity fresh coal injection jet.
This consideration would be o~ particular importance in hydrocarbonization where the heat of reaction i9 only slightly exothermic.
As the relative ratio of the relativel~ cold injec-tion 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 3569 ~ Y~

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, in its various aspects, enhances the technical and economic feasibility of desirable coal conversion operations, provides advanta-geous flexibility in meeting the overall heat and materialbalance limitations of commercial plant designs, and con-stitutes a major advance in the important efforts being undertaken to develop practical technologies for the use of caking coals in meeting the overincreasing energy requirements of modern industrial societies.

Claims (8)

THEREFORE, WE CLAIM:

1. A method for substantially preventing defluidization in a fluid-bed reaction zone maintained at a reaction temperature above about 450°C and containing a bed of non-agglomerating particles at the reaction temperature, said method comprising:
(a) introducing fresh solid carbonaceous particles in a carrier gas into said reaction zone through injection nozzle means at an injection velocity in excess of about 20 ft./sec., said solid carbonaceous particles being injected directly into said reaction zone and into direct contact with the non-agglomerating particles therein;
(b) introducing a gaseous reagent into said reaction zone for fluidizing said bed and for reaction with said fresh solid carbonaceous particles at said reaction temperature within said zone;
(c) passing a shroud gas through a shroud passage on said injection nozzle means and into said reaction zone, the overall energy input to said reaction zone for dispersion of said fresh particles within the bed of non-agglomerating particles and to grind agglomerates of said fresh particles that may tend to form upon injection of said fresh particles into said reaction zone comprising that supplied by the fluidizing-reagent gas by the carrier gas for said fresh carbonaceous feed, by said shroud gas and by attrition jets positioned to break up said agglomerates, said overall energy input being above the minimum energy level for the particular carbonaceous particles fed to said reaction zone, whereby said solid carbonaceous particles are effectively dispersed within said bed of non-agglomerating particles without undue agglomeration and without consequent bed failure and defluidization in said fluid-bed reaction zone.

2. The method of Claim 1 in which said injection velocity of solid carbonaceous particles is at least about 200 ft./sec.

3. The method of Claim 2 in which said solid carbonaceous particles are preheated to a temperature essentially within the plastic transformation temperature range for said particles, the relatively hot, fresh particles tending to minimize nozzle erosion at the high injection velocities employed.

4. The method of Claim 3 in which said preheat temperature is from about 325°C to about 400°C.

5. The method of Claim 1 in which said injection velocity of fresh solid carbonaceous particles is at Least about 400 ft./sec.

6. The method of Claim 1 in which the shroud gas furnishes at least about 80% of said overall energy input to said reaction zone.

7. The method of Claim 6 in which said shroud gas comprises an inert gas not reacting with said fresh solid carbonaceous particles at the reaction conditions, said shroud gas velocity being from about 750 to about 5,000 ft./sec.

8. The method of Claim 2 in which said overall energy input is at least about 10 x 10-4 hp-hr per pound of coal fed to the reaction zone.