Title of Invention

A PROCESS FOR THE HYDROGENATION OF COAL AND A REACTOR THEREFOR

Abstract

An improved process for the hydrogenation of coal which comprises subjecting particulate coal to react with gaseous Hydrogen at high temperatures, by subjecting dry coal particles made free of gypsum by extracting the same using 50% water solution of glycerol and drying at 65°C, such that kaolinite, silica and iron pyrites contained is maintained intact in coal particles 70% of which having selective 200 mesh size, first to pre heating at 600 to 650°C in presence of hot hydrogen gas at a pressure of 1000-1500psi so as to achieve a quick preheating. Thereafter, the pre heated coal is allowed to undergo hydrogenation at temperature range of 400 to 450°C. The invention also involves a reactor for carrying out the above process wherein two contiguous sections one of which is pre heating zone and the other being the hydrogenation/reaction zone, carry out said preheating of the coal particles and then desired faster hydrogenation to obtain about 98% liquefied coal.

Full Text

FIELD OF THE INVENTION This invention relates to an improved process for the hydrogenation of coal. More particularly, the invention relates to an improved method of liquefaction of coal by solid phase hydrogenation of coal. According to another aspect of the present invention, the same is directed to a reactor for carrying out said process of hydrogenation of dry particulate coal of selective mesh size, made free of gypsum. BACKGROUND ART It is already known in the related art that coal particles subjected to liquefaction by pyrolysis. It is also known in the art that hydrogenation of coal has been carried out catalytically. The catalyst used is usually molybdenum oxide. In the prior art process, the product obtained is either fuel oil or a mixture of BTX liquids and gas or synthetic natural gas depending on the proper combination of time, temperature and hydrogen partial pressure. The advantage of such a process against liquid phase hydrogenation is that it takes very little time(of the order of few seconds) to convert coal, when in direct contact with hydrogen. The mechanism by which coal is converted is as follows: Coal+heat ? Free radicals. Free radicals + H2 ? Heavy and light liquid. Heavy and light liquid + H2 ? Gas. It must be appreciated that bituminous coal goes through a plastic region during the above conversion. Thus in the known art using fluidized bed reactors, there is the problem of efficient conversion of coal to desired products. The agglomeration of coal not only reduces the yield of the desired products but also causes operational problems due to sticky nature of the particles on the bed. Other drawback is that unwanted gaseous products also result to substantial extent. It has been observed that raw coal mineral matters contain both catalysts and poisons. The catalysts are kaolinite, silica and iron pyrites. Silica and kaolinite act as cracking catalysts whereas iron pyrites acts as hydrogenation catalyst. Gypsum present in raw coal is poisonous. There had been thus a need for in-depth study of the role played by each component present in the raw coal and to thereby developing an improved process for hydrogenation of coal, avoiding the limitations and disadvantages of the prior art processes as given herein above. OBJECTS OF THE INVENTION The basic object of the present invention is directed to an improved method and a reactor for the liquefaction of coal by solid phase hydrogenation of coal. Another object of the invention is directed to a method for solid phase hydrogenation of coal wherein agglomeration of coal particles is totally avoided. A further object of the present invention is to propose an improved reactor where instantaneous heating of the coal particles to desired temperature is achieved. A still further object of the invention is directed to totally dispense with fluidized bed conversion. A still further object of this invention is directed to a method for liquefaction of coal whereby there is provided efficient exposure of the coal particle to the hot gas, namely hydrogen. SUMMARY OF THE INVENTION The basic aspect of the present invention is thus directed to a process for the hydrogenation of coal comprising: (a) treating the coal particles to a step of separation of the gypsum contained in the coal by solvent extraction using 50% water solution of glycerol to leave behind kaolinite, silica and iron pyrites contained in the coal in tact; (b) drying the gypsum free coal by hot inert gas preferably Nitrogen at about 65°C; (c) subjecting the gypsum free coal particles to a step of pre-heating in the presence of Hydrogen gas at temperature in the range of 600°-650°C and at a pressure of 1000-1500 psi so as to achieve a quick pre-heating of the particulate coal; and (d) thereafter, allowing the pre-heated coal to undergo hydrogenation with gaseous Hydrogen at a temperature in the range of 400° to 450°C. Another aspect of the present invention is directed to a process for the hydrogenation of coal wherein the coal having gypsum is subjected to a step of fluidization for 15 to 20 minutes by the 50% glycerol water solution and the extraction of gypsum is carried by the effluent stream. A still further aspect of the present invention is directed to a process for the hydrogenation of coal wherein the coal is held on a perforated bottom plate in an extractor and the 50% glycerol water solution is passed from below the plate at a speed of 0.5 cm per second till most of the gypsum is removed. said process for the hydrogenation of coal wherein a major portion of the particulate coal passes through 200 mesh. Also according to an aspect of the process for the hydrogenation of coal as of the present invention wherein at least 70% of the particulate coal passes through 200 mesh screen. According to yet another aspect of the present invention directed to a process for the hydrogenation of coal wherein drying is carried out using hot nitrogen preferably by fluidization. A still further aspect of the present invention is directed to a process for the hydrogenation of coal wherein the preheating of the dried coal particles is carried out to about 450°C by feeding the coal vertically from the top of a preheating zone and admitting the high pressure hot hydrogen gas from a horizontal direction to impinge on the coal particles at 90°C by creating vortex inside the pre heater in addition to free jet turbulence. said process for the hydrogenation of coal wherein the pre heated coal is allowed to undergo complete hydrogenation subsequently for the time required. According to yet another important aspect of the present invention is directed to a reactor for the hydrogenation of particulate coal which comprises: a) a coal preheating zone and a hydrogenation zone contiguous with one and other and in the same horizontal plane; b) said preheating zone being shorter in length but larger in width and height than the reaction zone; c) said preheating zone having an inlet for the admission of hydrogen gas and an inlet for admission of the dry coal particles, the preheating zone being provided with a set of small metallic spheres along the horizontal path of the hydrogen gas as well as along the vertical section. said reactor for hydrogenation of particulate coal where in the inlet of the coal is provided at the front wall vertically, preferably at the middle of the front wall. Also in said reactor for the hydrogenation of the particulate coal the inlet for the hydrogen gas is provided at the left side wall of the reactor opposite to the side right wall where the reaction zone is provided. According to another aspect of the reactor for the hydrogenation of particulate coal as of the present invention wherein the inlet for the hydrogen gas and the reaction zone are preferably in the same horizontal plane. A further aspect of the present invention is directed to said reactor for the hydrogenation of particulate coal wherein at least two rows of the small metallic spheres are provided within the preheating zone from the inside of the front, back and top and bottom of the pre heater walls by means of thin rods. According to another preferred aspect of said reactor for the hydrogenation of particulate coal wherein the spheres are provided in a predetermined manner such that a vortex is created around each sphere as the hydrogen gas passes around it creating a vortex in addition to free turbulence for the intimate mixing and preheating of the coal inside the pre heater. These and other objects will be more clearly understood from the following paragraphs with reference to the non-limiting illustrative figure. BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES Figure 1: illustrates a simple schematic diagram of the reactor used for carrying out the hydrogenation process of coal according to the invention; Figure 2: illustrates a partial cross section of the reactor showing the inner details of the front side/face of the pre heater of the reactor. DETAILED DESCRIPTON OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING FIGURES The process according to the present invention is directed to a method of liquefaction of coal by solid phase hydrogenation of coal. The present process involves removing the poison from the coal by extracting gypsum with a glycerol and water solution. After removing gypsum, the coal is dried and then fed to a new short residence time reactor not disclosed earlier. The advantages of this new process and new reactor are: (i) It gives a yield as high as 98% liquid; (ii) No external catalyst is added and there is no question of recovering the catalyst. Reference is first Invited to the accompanying Figure 1 that illustrates the schematic diagram of the reactor for carrying out the process for liquefaction and hydrogenation of coal according to the present invention. The reactor consists of two adjacent sections e.g. A & B, wherein the coal preheating section is identified as 'A' and then a reaction section lB', at its right wall preferably in the middle region, both the sections 'A' & 'B' are substantially square in cross section as illustrated in said Figure 1. The preheating zone has an inlet 'C' vertically provided at the upper front end of the preheating zone 'A' and more preferably located at the top center of the front wall of the preheating zone for admitting gypsum free dry coal particles inside the reactor/preheating zone. Similarly, the preheating zone is also provided with an inlet 'D' for the supply of hot hydrogen gas at its left wall, opposite to the reaction zone 'B' at its right wall. The cubical shaped (square cross section) preheating zone thus having supply of hot hydrogen gas through the inlet on the left wall and right wall connected to the reaction zone, while the top wall has a coal inlet at its front middle end. Attention is now invited to the accompanying Figure 2 that illustrates the frontal sectional view of the preheating zone, showing the internal details of the reactor for carrying out the liquefaction/hydrogenation process of coal according to the present invention. As clearly apparent from the accompanying Figure 2, in the preheating section 'A', there are at least two sets of spheres/steel balls (SB) separately located in at least two rows in vertical planes on bottom (BW), top (TW), front (FW) and back walls (BW) of the pre-heater having a specified/selective clearance between the spheres (SB) and between the two sets of rows. The spheres/steel balls (SB) are kept in place by means of thin rods attached to them and the rods being welded to the walls of the preheating section (A) and are located in the main central path of the gas inside the preheating zone. The coal particles are subjected to a step of separation of the gypsum contained in the coal by solvent extraction process using 50% water solution of glycerol to leave behind kaolinite, silica and iron pyrites originally contained in the coal intact. The gypsum is subjected to a step of fluidization for 15 to 20 minutes in the 50% glycerol water solution and the extraction of gypsum is carried by the effluent stream. Initially, drying of gypsum free coal particles is carried out by hot inert nitrogen gas at around 65°C, preferably by fluidization, before feeding inside the preheating zone of the reactor. The coal particles are held on a perforated bottom plate in an extractor and the 50% glycerol water solution is passed from below the plate at a speed of 0.5 cm per second, till most of the gypsum is removed. A major potion of the particulate coal, preferably at least 70% of the particulate coai passes through 200mesh screen. The preheating of the dried coal particles is carried out at temperature in the range of 600°- 650°C and at a pressure of 1000-1500 psi so as to achieve a quick preheating of the particulate coal, by feeding the coal vertically from the top of the preheating zone and admitting the high pressure hot hydrogen gas from a horizontal direction to impinge on the coal particles at 90 degrees, by creating vortex inside the pre heater in addition to free jet turbulence, for desired intimate mixing and favoured quick preheating of the coal inside the preheater. The H2 jets entering the reactor from the side of the section A, after entry of coal feed into the reactor preferably from the top as gypsum free dry coal particles, preheats the coal due to the mixing caused by the turbulent jet. But, additional mixing is obtained when the jet hits the spheres due to separation of boundary layers around the spheres and mixing behind the spheres due to backward flow. This phenomena are witnessed at the site of each of the spheres in the flow path of the H2 gas. The preheated coal particles are then allowed to undergo complete hydrogenation in the next reaction zone with gaseous Hydrogen at a temperature in the range of 400° to 450°C for required time duration. It is thus possible by way of the present invention to achieve liquefaction of coal by solid phase hydrogenation by the reaction of dry coal particles with hot hydrogen gas with selective parameters, in a simple, fast and cost effective manner using the simple reactor system of the invention. Due to the presence of a plurality of small steel balls arranged in a predetermined manner, the vertically fed coal particles are swept away by the hot horizontal stream of hydrogen inside the pre heater zone of the reactor. The gas flow at high velocity creates vortex as well as free jet turbulence around the steel balls, resulting in very quick pre-heating of coal and then undergoes hydrogenation giving about 98% liquefied coal as output of the process using the reactor system. The process of the present invention further avoids use of any external catalysts as experienced in the conventional process and is not only fast due to removal of poison but also productive and economic, making such process and the system to carry out such process for solid phase hydrogenation and liquefaction of coal, capable of wide industrial application for a number of end uses. I Claim: 1. A process for the hydrogenation of coal comprising: (a) treating the coal particles to a step of separation of the gypsum contained in the coal by solvent extraction using 50% water solution of glycerol to leave behind kaolinite, silica and iron pyrites contained in the coal in tact; (b) drying the gypsum free coal by hot inert gas preferably Nitrogen at about 65°C; (c) subjecting the gypsum free coal particles to a step of pre-heating in the presence of Hydrogen gas at temperature in the range of 600°-650°C and at a pressure of 1000-1500 psi so as to achieve a quick pre-heating of the particulate coal; and (d) thereafter, allowing the pre-heated coal to undergo hydrogenation with gaseous Hydrogen at a temperature in the range of 400° to 450°C. 2. A process for the hydrogenation of coal as claimed in claim 1 wherein the coal having gypsum is subjected to a step of fluidization for 15 to 20 minutes by the 50% glycerol water solution and the extraction of gypsum is carried by the effluent stream. 3. A process for the hydrogenation of coal as claimed in anyone of claims 1 or 2 wherein the coal is held on a perforated bottom plate in an extractor and the 50% glycerol water solution is passed from below the plate at a speed of 0.5 cm per second till most of the gypsum is removed. 4. A process for the hydrogenation of coal as claimed in anyone of claims 1 to 3 wherein a major portion of the particulate coal passes through 200 mesh. 5. A process for the hydrogenation of coal as claimed in claim 4 wherein atleast 70% of the particulate coal passes through 200 mesh screen. 6. A process for the hydrogenation of coal as claimed in anyone of claims 1 to 5 wherein drying is carried out using hot nitrogen preferably by fluidization. 7. A process for the hydrogenation of coal as claimed in anyone of claims 1 to 6 wherein the pre heating of the dried coal particles is carried out to about 450°C by feeding the coal vertically from the top of a pre heating zone and admitting the high pressure hot hydrogen gas from a horizontal direction to impinge on the coal particles at 90°C by creating vortex inside the pre heater in addition to free jet turbulence. 8. A process for the hydrogenation of coal as claimed in anyone of claims 1 to 7 wherein the pre-heated coal is allowed to undergo complete hydrogenation subsequently for the time required. 9. A reactor for the hydrogenation of particulate coal which comprises: a) a coal preheating zone and a hydrogenation zone contiguous with one and other and in the same horizontal plane; b) said preheating zone being shorter in length but larger in width and height than the reaction zone; c) said preheating zone having an inlet for the admission of hydrogen gas and an inlet for admission of the dry coal particles, the preheating zone being provided with a set of small metallic spheres along the horizontal path of the hydrogen gas as well as along the vertical section. 10. A reactor for hydrogenation of particulate coal as claimed in claim 9 where in the inlet of the coal is provided at the front wall vertically, preferably at the middle of the front wall. 11. A reactor for the hydrogenation of the particulate coal as claimed in claim 9 wherein the inlet for the hydrogen gas is provided at the left side wall of the reactor opposite to the side right wall where the reaction zone is provided. 12. A reactor for the hydrogenation of particulate coal as claimed in claim 9 wherein the inlet for the hydrogen gas and the reaction zone are preferably in the same horizontal plane. 13. A reactor for the hydrogenation of particulate coal as claimed in claim 9 wherein at least two rows of the small metallic spheres are provided within the preheating zone from the inside of the front, back and top and bottom of the pre heater walls by means of thin rods. 14. A reactor for the hydrogenation of particulate coal as claimed in claim 9 wherein the spheres are provided in a pre determined manner such that a vortex is created around each sphere as the hydrogen gas passes around it creating a vortex in addition to free turbulence for the intimate mixing and preheating of the coal inside the pre heater. 15. A process for the hydrogenation of coal and a reactor for use in such process substantially as hereindescribed and illustrated with reference to the accompanying figures. An improved process for the hydrogenation of coal which comprises subjecting particulate coal to react with gaseous Hydrogen at high temperatures, by subjecting dry coal particles made free of gypsum by extracting the same using 50% water solution of glycerol and drying at 65°C, such that kaolinite, silica and iron pyrites contained is maintained intact in coal particles 70% of which having selective 200 mesh size, first to pre heating at 600 to 650°C in presence of hot hydrogen gas at a pressure of 1000-1500psi so as to achieve a quick preheating. Thereafter, the pre heated coal is allowed to undergo hydrogenation at temperature range of 400 to 450°C. The invention also involves a reactor for carrying out the above process wherein two contiguous sections one of which is pre heating zone and the other being the hydrogenation/reaction zone, carry out said preheating of the coal particles and then desired faster hydrogenation to obtain about 98% liquefied coal.

Documents:

5-cal-2002-abstract.pdf

5-cal-2002-claims.pdf

5-CAL-2002-CORRESPONDENCE 1.1.pdf

5-cal-2002-correspondence.pdf

5-cal-2002-description (complete).pdf

5-cal-2002-drawings.pdf

5-cal-2002-examination report.pdf

5-cal-2002-form 1.pdf

5-cal-2002-form 13.pdf

5-cal-2002-form 18.pdf

5-cal-2002-form 2.pdf

5-CAL-2002-FORM 27.pdf

5-cal-2002-form 3.pdf

5-cal-2002-form 5.pdf

5-cal-2002-granted-abstract.pdf

5-cal-2002-granted-claims.pdf

5-cal-2002-granted-correspondence.pdf

5-cal-2002-granted-description (complete).pdf

5-cal-2002-granted-drawings.pdf

5-cal-2002-granted-examination report.pdf

5-cal-2002-granted-form 1.pdf

5-cal-2002-granted-form 13.pdf

5-cal-2002-granted-form 18.pdf

5-cal-2002-granted-form 2.pdf

5-cal-2002-granted-form 3.pdf

5-cal-2002-granted-form 5.pdf

5-cal-2002-granted-pa.pdf

5-cal-2002-granted-reply to examination report.pdf

5-cal-2002-granted-specification.pdf

5-cal-2002-pa.pdf

5-cal-2002-reply to examination report.pdf

5-cal-2002-specification.pdf