MXPA98000943A

MXPA98000943A - Method and apparatus to reduce the content of sub-products in carbonac materials

Info

Publication number: MXPA98000943A
Application number: MXPA/A/1998/000943A
Authority: MX
Inventors: Koppelman Finado Edward
Original assignee: Kfx Inc
Priority date: 1995-08-09
Filing date: 1998-02-03
Publication date: 1998-04-01

Abstract

The present invention relates to various apparatuses and methods for treating carbonaceous materials to remove their by-products. More particularly, the present invention relates to the treatment of carbonaceous materials by injecting an inert gas into the carbonaceous material under vacuum or injecting steam into the carbonaceous material with or without the vacuum applied in a controlled manner, to treat more consistently Charge of carbonaceous material

Description

METHOD AND APPARATUS FOR REDUCING THE CONTENT OF SUB-PRODUCTS IN CARBONACEAL MATERIALS BACKGROUND OF THE INVENTION The present invention is particularly applicable, although it is not necessarily restricted to methods of processing carbonaceous materials when injecting steam under pressure or with vacuum or to reduce content of undesirable by-products and particularly sulfur of the carbonaceous material. Typical of the methods to which the present invention is applied is the treatment of various carbonaceous materials of natural origin, such as wood, tar or sub-bituminous coal to make them more suitable as a solid fuel. A number of inventions relating to improving carbonaceous fuel, have so far been employed or proposed to make the carbonaceous fuel more suitable as a solid fuel. Many problems are common such as extensive costs, both in manufacturing and operation of carbonaceous fuel improvement systems, difficult and complex controls to allow the operation of carbonaceous fuel improvement systems and a general lack of flexibility and versatility of this equipment for adaptation. in the processing of other materials at different temperatures and / or pressures.

While advances have been made in the art relating to many of the above-mentioned concerns, to date few systems have been proposed which refer to the use of steam condensate as a means to reduce the amount of by-products contained in the charge of carbonaceous materials. Of the known systems employing steam condensation, the apparatuses generally used do not include controls to ensure that the carbonaceous material is treated in a consistent manner substantially throughout the entire load. For example, the US patent. No. 5,071,447 issued to the inventor, describes methods and apparatuses for treating carbonaceous materials with steam. Under the system described in the '447 patent, steam is injected into the top of the processor, but there are no controls in place to direct the introduction of steam. In this way, the vapor condenses in the first material with which it comes into contact. This, in turn, causes additional steam entering the system to follow the path of least resistance through the material, resulting in an inhomogeneous distribution of condensation vapor which results in an inconsistently processed material. The methods and apparatus of the present invention overcome many of the problems and disadvantages associated with equipment and specialty techniques by providing units that are relatively simple in design, durable in construction, versatile in use, and easily adaptable to process different materials. of feeding in variants temperatures and / or pressures. The apparatuses of the present invention are also characterized by being simple to control and efficient in the use of thermal energy, thus providing economic operation and conservation of resources. Probably more importantly, the apparatuses and methods of the present invention specifically address a more consistent treatment of the carbonaceous material throughout the entire load. By providing an injector that evenly distributes the steam at the time of introduction and either internal tubes or a divider depending on the thermo-exchanger mode, a more consistent treatment of the carbonaceous materials is possible. SUMMARY OF THE INVENTION The benefits and advantages of the present invention are achieved by the following methods wherein under a first method, carbonaceous materials are charged in a heat exchange apparatus comprising at least one inner tube to receive the carbonaceous material surrounding by an outer cover. After the carbonaceous material is loaded in the heat exchange apparatus, the carbonaceous material is generally subjected to vacuum. While the inner tube or tubes containing the carbonaceous material are subjected to vacuum, a heat exchange medium having a temperature between about 121 ° C (250 ° F) to about 649 ° C (1200 ° F) and generally about 399 ° C (750 ° F) is circulated through the cover, such that the heat exchange medium is in contact with the outer periphery of the inner tube (s). After the carbonaceous material reaches a predetermined temperature, steam is injected into the inner tube (s), so that the vapor condenses in the carbonaceous material under vacuum. The carbonaceous material temperature remains elevated for a controlled period of time after the steam is injected to purge the material from various by-products. Sub-products, such as tar and particularly sulfur that have been displaced from the carbonaceous material, are recovered together with a gas through a valve located at the bottom of the thermo-exchanger. At the end of the thermo-exchange stage, the carbonaceous material is removed from the thermo-exchanger for further processing or storage. Under an alternate embodiment and method of the present invention, instead of loading the carbonaceous material into various internal tubes, the shell or enclosure is provided with an internal chamber for receiving the carbonaceous materials. The internal chamber is separated into various elongated, generally linear or "quadrant" sections by a divider, which typically extends the entire length of the chamber. After the carbonaceous material has been loaded into the chamber and the chamber is sealed, the carbonaceous material is again subjected to vacuum and then steam injected for a predetermined period of time to purge the unwanted by-product material. . A principal advantage of the present invention over systems for treating carbonaceous materials that is known is that the apparatuses and methods of the present invention specifically control the introduction of steam to give rise to a more consistent end product. BRIEF DESCRIPTION OF THE DRAWINGS Additional benefits and advantages of the present invention will be apparent from the reading of the description of the preferred embodiments that are taken in conjunction with the specific examples provided and the drawings, wherein: Figure 1 is a side elevation view of a first embodiment of a heat exchanger according to the teachings of the present invention; Figure 2 is a sectional view taken on line 2-2 of Figure 1; The Fi > Figure 3 is a partially exploded side elevation view illustrating a second embodiment of a heat exchanger according to the teachings of the present invention;torch.

Figure 4 is a sectional view taken on line 4-4 of Figure 3; and Figure 5 is a side elevational view showing a portion of the s injector structure of the present invention. DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The present invention is useful for purging undesirable byproducts such as sulfur from carbonaceous materials, including but not limited to, ground mineral coal, lignite, and sub-bituminous mineral carbons of the type widely encompassing wood, pitch, and coals. bituminous minerals, which are generally found in deposits similar to ground coal (bottom of a coal seam) ground. Carbonaceous materials as extracted, however generally include a certain amount of undesirable contaminants, otherwise referred to herein as by-products, which have little value, if any, as a fuel source. In this way, it is highly convenient to remove as much of the by-products as possible as possible to obtain a high-energy fuel. It is important to note from the start that "the particle size of the carbonaceous material" which is subjected to treatment as described herein, largely determines the time necessary to remove the byproducts from the carbonaceous material. In general, the larger the particle size the longer it takes to achieve a reduction in the undesirable byproducts of the carbonaceous material. Therefore, a close attention should be paid to particle size when carrying out the methods of the present invention. With reference to Figure 1, there is described a heat exchanger apparatus 10, "comprising an enclosure or cover 12, having a plurality of tubes 14 contained therein, generally extending along the length of the enclosure to retain the carbonaceous material for treatment. Each tube 14 is provided with an inlet 16 having a valve 18 and an outlet 20 including a valve 22. The thermo-exchanger 10 also includes a network for circulating a thermo-exchange medium through the enclosure including a plurality of channels 24 that extend generally along inside the enclosure. As further illustrated in Figure 1, a vacuum source 26 is generally connected directly to the plurality of tubes 14 to receive carbonaceous material towards the lower end of the tubes. Also, connected to the plurality of tubes 14 generally near the inlets 16, there is a source for injecting either pressurized inert gas and / or s generally designated by the reference number 28. It should be noted at this point that while " that it is preferred that the apparatus described with reference to Fig. 1 be equipped with a vacuum source 26, is not considered essential under the hings of the present invention since the unique application of pressurized gas, s and the like, offers an improvement in the amount of by-products that are recovered versus the known systems for treating carbonaceous materials. The enclosure 12 as illustrated in Figure 1 includes a network for circulating heat exchange medium through the heat exchange apparatus. The network includes an inlet 30 located on the lower end to introduce a heat exchange medium in the enclosure 12. The network also includes an outlet 32 located at the lower end of the enclosure to remove the thermo-exchange medium from the enclosure afterwards. of circulation by him. Ideally, the heat exchange medium will be cycled through an oven (not shown) to reheat the heat exchange medium before reintroduction to the heat exchanger. To carry out the method for treating carbonaceous material using the heat exchanger of Figure 1, carbonaceous material is charged to the plurality of tubes 14 through inlets 16 after closing the valves 22 located on the outlets 20. Al filling the tubes with the desired amount of carbonaceous material, the valves 18 located on the inlets 16 are closed to keep the carbonaceous material in a closed system.

A heat exchange medium such as heated gas, molten salt or preferably an oil, having a temperature between about 121 and 649 ° C (250 to 1200 ° F) and preferably about 399 ° C (750 ° F), subsequently it is circulated continuously through the enclosure by introducing the thermo-exchange medium through the inlet 30. The thermo-exchange medium travels up through the well 36 and then back through the plurality of channels 24 The thermo-exchange medium then passes through the outlet 32 to reheat before being reintroduced through the inlet 30. While the thermo-exchange medium is circulated through the enclosure 12, vacuum is optionally applied, but preferably it is applied to the plurality of tubes 14 containing the carbonaceous material. Subsequently, a gas such as an inlet gas, carbon dioxide, hydrogen or a combination of these gases is injected into the plurality of tubes 14, such that the gas acts as a heat transfer carrier upon contact with the inner walls of the tubes 14, absorbing heat and directing the heat to the carbonaceous material. The pressure at which the inert gas, carbon dioxide and optionally hydrogen are introduced and maintained within the tubes 14 may be in the range from about 406-2,109 kg / cm 2 gauge (about 2 to about 3,000 PSIG).

When hydrogen gas is employed, a stoichiometric amount of hydrogen is injected into the plurality of tubes to assist in directing the excess sulfur out of the carbonaceous material. By "stoichiometric amount", it is understood that the amount of hydrogen employed will be in direct correlation with the amount of sulfur contained in the carbonaceous material. In general, the higher the sulfur content, the more hydrogen is required to react giving rise to a hydrogen sulfide constituent gas that can be vented from the plurality of tubes. As a result of both heat and gravity, the moisture contained in the carbonaceous material evaporates and condenses or subsequently carbonaceous material contained within the plurality of tubes 14 which entrain displaced by-products of the carbonaceous material. Eventually, substantially all the water, by-products and particularly a relatively high concentration of sulfur is removed from the carbonaceous material and recovered through the outlets 20 before recovering the carbonaceous material. As previously noted, the amount of time required to treat the carbonaceous material within the heat exchanger apparatus will vary depending on the size of the carbonaceous material granules, the temperature at which the system is operated, the pressure of the gas injected into the tubes and the heating volume that is desired. Typically, the amount of time is in the range of about 3 minutes to about 30 minutes. The amount of time required for treatment generally decreases as the temperature and pressure increase within the heat exchanger. On the contrary, the amount of time required increases when lower temperatures and pressures are used. Under an alternate method for treating the carbonaceous material using the heat exchanger apparatus 10 as illustrated in Figure 1, after loading the plurality of tubes 14, by circulating the heat exchange medium through the plurality of channels 24 for a sufficient amount of time to raise the temperature of the carbonaceous material to the desired level and optionally apply to vacuum as described above, steam is injected into the plurality of tubes 24. The vapor is injected into the plurality of tubes 14 near the inlet 16 and maintained at a pressure between approximately 21.09 - 2,109 kg / cm2 gauge (about 300 to about 3000 PSIG), so that steam with high pressure travels down through the carbonaceous material. As the vapor condenses on the carbonaceous material as it travels down the pipes, the steam serves to purge the by-product material. After treating the material for a period of time in the general range of about 3 minutes to about 30 minutes, any gases contained within the tubes 24 are vented and the by-products are removed through the outlets 20. Subsequently, the treated carbonaceous material can be removed. Now with reference to Fig. 3, an alternate embodiment of a heat exchanger apparatus 110 is described, comprising an outer enclosure 112 having a relatively cylindrical shaped chamber 114 contained as illustrated more clearly in Fig. 4. Chamber 114 generally extends over a significant portion of enclosure 112 and serves to retain the carbonaceous material during the treatment process. Internally, chamber 114 is provided with a divider 140 that separates the chamber into a plurality of elongated sections to segregate the carbonaceous material before treatment, each section generally having approximately the same volumetric capacity "as any other given section. The heat exchanger 110 also includes one or more inlets 116 having valves 118 for introducing a charge of carbonaceous material into the various sections of the chamber and one or more outlets 120 having valves 122 for removing the carbonaceous material from the heat exchanger afterwards. of treatment. Located next to the lower end of the enclosure 112 on the valve 122, there is a valve 126 which is actuated to close the chamber 114 while the carbonaceous material is treated. Preferably, a space 128 is provided between the interior wall of the enclosure and the exterior wall of the chamber within which insulation material 142 as illustrated in Figure 3 is arranged to retain heat within the heat exchanger. The heat exchanger apparatus 110 also includes a steam injector 130 disposed on top of the chamber 114, to introduce steam into the various sections of the chamber. As more clearly illustrated in Figure 4, the steam injector typically includes an inner ring 132 and an outer ring 134, each of which has a plurality of downwardly extending nozzles 136, for introducing steam into the various sections of the camera in a specific form of area. The inner and outer rings are joined at least by a conduit 138 into which the steam is originally introduced. To carry out the method for treating the carbonaceous material used in the thermo-exchanger of Figure 4, carbonaceous material is charged into chamber 114 through inlet 116 «which feeds directly into the chamber, after ensuring that the valve 126 located at the lower end of the chamber, closes. By filling the various sections of the chamber with carbonaceous material, the valves 118 located over the inlets 116 are sealed or closed to keep the carbonaceous material in a closed system within the chamber. Subsequently, steam is introduced through the injector, "which in turn substantially uniformly distributes the vapor through the various sections of the chamber. By distributing the vapor uniformly through each chamber section, the vapor is allowed to "condense relatively uniformly in the carbonaceous material. Ideally, the pressure at which the vapor is maintained within the chamber 114 will be in the order of between about 21.09 and about 2.109 kg / cm2 gauge (about 300 to about 3000 PSIG), depending primarily on the requirements in kilo- calories (btu) for any given charge of carbonaceous material. As the vapor condenses and moves downwardly through the carbonaceous material, the divider 140 serves to ensure that the amount of condensation vapor in any one of the sections is approximately equivalent to that contained in another section. As a result of the uniform distribution of steam through the chamber, superior consistency with respect to the treated carbonaceous material can be achieved. After treating the carbonaceous material for a sufficient amount of time, typically in the range of between about 3 minutes to about 30 minutes, the valves 122 and 126 respectively are opened to vent any gases such as hydrogen sulfide gas which have been generated. as a result of which the condensation vapor reacts with the carbonaceous material. In addition, any by-products in the form of water containing contaminants are also recovered through the valve 126. After the gases and other by-products have been discharged, the carbonaceous material can then be recovered through one or more outputs 120 that are provided on the lower end of the heat exchanger apparatus. The "treated" carbonaceous material produced according to the aforementioned methods, using the apparatuses illustrated in Figures 1 to 5, undergoes both physical restructuring and chemical restructuring. By "physical restructuring" it is meant that the average particle size of the carbonaceous material is reduced by a factor of approximately 25 percent on average. This reduction in particle size causes the particles to become denser, thus allowing the carbonaceous material to burn for a longer time, which is highly convenient. The so-called "chemical restructuring" is more easily evidenced by gaseous emissions that result from treating the carbonaceous material at elevated temperatures and pressures as described above. In addition, by-product gaseous hydrogen sulfide still other gaseous by-products including, but not limited to, carbon dioxide, carbon monoxide and methane, often result. As evidenced by infrared analysis, in general, the gaseous by-products result from the decarboxylation of the carbonaceous material, where a significant reduction in the number of carbon-oxygen bonds forming the bonds in the carbonaceous material is experienced. In addition, the decomposition of carboxylic acids and phenols is considered to effect a reduction in the equilibrium moisture content. Those with skill in the art will now come to appreciate some of the advantages of the present invention, such as a more consistent treatment of carbonaceous materials and more particularly, a higher concentration of recovered by-products, which in turn gives rise to the materials carbonáceos that have a greater capacity like fuel. The person skilled in the art will detect even further advantages of the invention after having the benefit of studying the specification, drawings and if "further claims.

Claims

CLAIMS 1. An apparatus for removing by-products of carbonaceous materials, characterized in that it comprises: a thermo-exchanger that includes an external enclosure, an inlet for a charge of carbonaceous material located on a first end of the enclosure and a localized outlet on a second end of the enclosure, at least one tube member contained within the enclosure to receive a charge of carbonaceous material, one or more valves located on the first end to introduce the charge of carbonaceous material into at least one tube and one or more valves located on the second end to remove the charge of the carbonaceous material; means for circulating a heat exchange medium through the outer enclosure, wherein the heat exchange medium is heated to a temperature between about 121 and about 649 ° C (about 250 ° F to about 1200 ° F); means for applying a vacuum at least to a tube containing a charge of carbonaceous material; and means for introducing a treatment medium in the gas form within the tube that at least contains a charge of carbonaceous material in said vacuum.
2. The apparatus according to claim 1, characterized in that the gas is inerted under pressure.
3. The apparatus according to claim 2, characterized in that the hydrogen gas is introduced together with the inert gas in the tube at least containing a carbonaceous material.
4. The apparatus according to claim 1, characterized in that the gas is vapor.
5. The apparatus in accordance with the claim 1, characterized in that the means for circulating a thermo-exchange medium through the outer enclosure include: a well "that extends upwards into the enclosure from the lower end through which the thermo-exchange medium is introduced to the enclosure; a plurality of downwardly extending channels, within which circulate thermo-exchange medium from the well; and an outlet through which the heat exchange medium leaves the apparatus for reheating.
6. An apparatus for removing by-products of carbonaceous material, characterized in that it comprises: a "heat exchanger" that includes an exterior enclosure and an interior chamber, an entrance located on a first end of the enclosure to introduce a charge of carbonaceous material inside the chamber , an outlet located on a second end of the enclosure for removing the charge of carbonaceous material, valve means operable to close the chamber for treatment of carbonaceous material and a divider for segregating the chamber into a plurality of elongated sections for housing the carbonaceous material; and means for introducing steam into one or more sections of the chamber, wherein the vapor is substantially evenly distributed within each section into which it is introduced.
The apparatus according to claim 6, characterized in that the divider segregates the chamber into sections that substantially have the same volumetric capacity as any other given section.
The apparatus according to claim 7, characterized in that the divider serves to prevent steam introduced in one section from entering another section.
The apparatus according to claim 6, characterized in that the means for introducing steam into one or more sections of the chamber includes an injector located on top of the chamber, comprising an inner ring and an outer ring attached at least by a conduit for introducing steam into the rings, the rings include a plurality of nozzles that extend downward to introduce steam into the elongated sections in a specific manner in area.
10. The apparatus in accordance with the claim 6, characterized in that it also comprises a space arranged between the outer enclosure and the inner chamber, which is provided with insulation to retain heat inside the inner chamber.
11. A process for removing by-products of carbonaceous materials, characterized in that it comprises the steps of: (a) providing a thermo-exchanger having at least one tube contained within an outer enclosure, an entry for introducing carbonaceous material into the tube at least , an outlet for removing the carbonaceous material from the tube at least and an inlet for introducing gas under pressure into the tube at least; (b) circulating a heat exchanger medium having a temperature of at least 93 ° C (200 ° F) through the outer enclosure to effect an increase in the temperature of the carbonaceous material; (c) applying a vacuum at least to the tube containing at least carbonaceous material; (d) injecting gas under pressure through the inlet in the tube at least containing carbonaceous material; and (e) recovering the solid carbonaceous material through the outlet.
12. The process according to claim 11, characterized in that the pressurized gas introduced into the tube at least is maintained between about 1406-2,109 kg / cm 2 gauge (about 2 to about 3,000 PSIG).
The method according to claim 11, characterized in that the charge of carbonaceous material remains in the tube at least during treatment for at least about 3 minutes.
14. The method according to claim 11, characterized in that the pressurized gas introduced into the tube at least includes an inert gas.
15. The process according to claim 14, characterized in that the gas under pressure also includes gas-hydrogen.
16. The method according to claim 11, characterized in that the pressurized gas is steam.
17. A process for removing by-products of carbonaceous materials, characterized in that it comprises the steps of: (a) providing a heat exchanger including an outer enclosure and an inner chamber, an inlet for introducing carbonaceous material into the inner chamber, outlet for removing carbonaceous material from the chamber, a divider disposed within the interior chamber for segregating the interior chamber into a plurality of elongated sections and an injector for introducing vapor into one or more sections of the chamber, such that the vapor introduces in a substantially uniform form in any given chamber section; (b) introducing steam in one or more sections of the chamber for a sufficient amount of time to effect a chemical restructuring of the carbonaceous material in such a way that by-products are removed from the carbonaceous material; and (c) removing the chemically re-structured carbonaceous material.
18. The method according to claim 17, characterized in that steam is introduced substantially uniformly through the entire chamber.
The process according to claim 17, characterized in that steam is introduced into one or more of said sections at desired temperature and pressure for at least about 3 minutes.
The method according to claim 16, characterized in that a space is provided between the outer enclosure and the inner chamber for receiving insulation material, which serves to retain heat inside the inner chamber.
21. A process for removing by-products of carbonaceous materials, characterized in that it comprises the steps of: (a) providing a heat exchanger having at least one tube contained within an outer enclosure, an inlet for introducing carbonaceous material into the tube at least one outlet for removing the carbonaceous material from the pipe at least and one inlet for introducing steam under pressure into the pipe at least; (b) circulating a heat exchanger medium having a temperature of at least 93 ° C (200 ° F) through the outer enclosure to effect an increase in the temperature of the carbonaceous material; (c) pressure steam injected through the inlet into the tube at least containing carbonaceous material; and (d) recovering the solid carbonaceous material through the outlet.
22. The method according to claim 21, characterized in that the pressure steam introduced into the tube at least is maintained between approximately 1406 and 2,109 kg / cm 2 gauge (approximately 2 to approximately 3,000 PSIG).
23. The method according to claim 21, characterized in that the charge of carbonaceous material remains in the tube at least during treatment for at least about 3 minutes.