METHOD AND SYSTEM FOR COAL PURIFICATION AND COMPLETE BURNING FOR CLEAN FOSSIL FUEL

Abstract

In one aspect, a method for coal purification and gasification may include steps of heating the coal including various hydrocarbons and harmful substances such as sulfides, phosphates, etc. to 900 to 1200° C. in a coal gasifier; providing a reaction chamber with oxygen and connecting with the coal gasifier; the sulfides, phosphates, etc. in the gasified coal entering the reaction chamber from the coal gasifier and reacting with the oxygen therein; separating mixtures from the reaction chamber to collect hydrocarbons in its fluidized phase; heating the fluidized hydrocarbons; and providing oxygen to react with the gasified form of hydrocarbons to achieve a complete burning of the hydrocarbons.

Description

FIELD OF THE INVENTION

The present invention relates to a coal gasification process, and more particularly to a coal gasification process in which the coal can be completely gasified and completely burning to reduce pollution.

BACKGROUND OF THE INVENTION

One of the main sources of atmospheric pollutants today is from coal-fired electrical utility boilers. In these installations, a clean fossil fuel, such as natural gas, is not a practical substitute for coal in the generation of electricity because of scarcity and cost. Furthermore, the available supply of clean fuel may combat pollution more effectively when used to fulfill residential and small commercial needs.

During conventional coal burning or gasification process, when the temperature is above the coal's softening point, plastic properties of coal start to develop. Upon reaching this point, generally between about 370° C. and about 480° C., the coal particles begin to swell and deform due to the formation of bubbles during devolatilization. As the temperature increases, deformation becomes more severe, the coal becomes plastic and sticky, and may eventually become thin films surrounding the incompletely burning small particles. At this stage, the coal is considered incompletely gasified. The coal may then break into small tiny fine solid carbon particles and emit into the air like “black smog.” The particles are solid, toxic and seriously carcinogenic, so when a great amount of the black solid carbon particles are emitted into the air, not only the environment is polluted, but the human health is seriously harmed. Therefore, there remains a need for a new and improved coal gasified process to avoid producing the harmful substances likewise “black solid smog” in the exhausted gas and make the coal completely gasify and to burn completely, and released less carbon dioxide to overcome the problems stated above.

SUMMARY OF THE INVENTION

Coal in the conventional burning, the solid form and air may not mix well before burning. In other word, the purpose of complete burning may not be achieved. To achieve complete burning, the coal in the solid form has to become gasified form, charged with electrostatic positive of the coal which can be mixed well with oxygen charged with electrostatic negative before burning to achieve complete burning purposes.

In one aspect, an improved coal gasification and purification system may include a coal gasifier, a reaction zone and a separation zone. In one embodiment, the coal is being heated without air to 900 to 1200° C. in the coal gasifier to become flammable gas and tars can be separated and fall down through the coal tar outlet pipe to the train and move away. In another embodiment, the coal can be continuously fed into the coal gasifier from the coal inlet pipe and the flammable gas, after pass through the gas filter being transported toward the reaction zone by a plurality of motors while being gasified.

The gasified coal then enters the reaction zone, the harmful substances such as sulfur (S) will be oxidized with oxygen to becoming sulfur trioxide (SO₃) therein, as shown in formula (i) below. And sulfur trioxide (SO₃) can further react with benzene (C₆H₆) in the reaction chamber as shown in formula (ii) below, which is called a sulfonation process to generate benzenesulfonic acid (C₆H₅SO₃H). It is noted that benzenesulfonic acid (C₆H₅SO₃H) can also be separated in the separation zone, and after add the water to becoming benzene and hydrosulfate acid (H₂SO₄). The hydrosulfate acid can be eliminated, and the benzene will be added back with the other coal hydrocarbons, as shown in formula below.

Sulfonation:

2S+3O₂=2SO₃  (i)

C₆H₆+SO₃=C₆H₅SO₃H  (ii)

C₆H₅SO₃H+H₂O=C₆H₆+H₂SO₄  (iii)

Same as sulfide, could be another harmful substances: phosphorous (P), after enters the reaction zone to react with oxygen after oxidation becoming phosphor trioxide (PO₃) etc. Also “benzene” will react with phosphor trioxide becoming phenyl phosphoric acid (C₆H₅PO₃H). After being separated, and isolated and add water becoming hydro-phosphoric acid (H₂PO₄) and benzene. The hydro-phosphoric acid (H₂PO₄) can be eliminated, and benzene will be added back with the other coal hydrocarbons, as shown in formula below.

Phosphoriation:

2P+3O₂=2PO₃  (iv)

C₆H₆+PO₃=C₆H₅PO₃H  (v)

C₆H₅PO₃H+H₂O=C₆H₆+H₂PO₄  (vi)

Since each substance has different boiling point, the mixture can be separated by fractional distillation through which various hydrocarbons, eliminated the harmful hydrosulfate acid, and hydro-phosphoric acid, in the separation zone (described above). It is noted that the purified coal gas may include various types of hydrocarbons, such as benzene, toluene, olefin, xylene, paraffin hydrocarbon, styrene, naphthalene, etc. with difference boiling points. The more importantly, during the fractional distillation process, the coal is fluidized and cleaned, and saved as clean fossil fuel can be used in the future.

For a coal burning process, the fluidized hydrocarbons can be reheated to gasified hydrocarbons and positively charged in a first reaction chamber. Meanwhile, the oxygen in the air is negatively charged enters the second reaction chamber connecting with the first reaction chamber. The positively charged hydrocarbons and the negatively charged oxygen can both travel to a third reaction chamber where the hydrocarbons can be burned in the stove after mixed well with the oxygen to achieve the goal of the “complete” coal burning to reduce pollution since the harmful substances were removed in the coal fluidized process discussed above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the coal purification and gasification system to eliminate harmful substances in the present invention.

FIG. 1a is a schematic view of the feedback control system to control the electric heater in the present invention.

FIG. 2 is a schematic view of the reaction of reheating the purified fluidic hydrocarbons, which is gasified to mix with oxygen to achieve complete burning in the present invention.

FIG. 3 illustrates a method for coal purification and gasification in the present invention.

FIG. 4 illustrates a carbon dioxide (CO₂) removal process in the present invention.

FIG. 5 illustrates another embodiment of a carbon dioxide (CO₂) removal process in the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The detailed description set forth below is intended as a description of the presently exemplary device provided in accordance with aspects of the present invention and is not intended to represent the only forms in which the present invention may be prepared or utilized. It is to be understood, rather, that the same or equivalent functions and components may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices and materials similar or equivalent to those described can be used in the practice or testing of the invention, the exemplary methods, devices and materials are now described.

All publications mentioned are incorporated by reference for the purpose of describing and disclosing, for example, the designs and methodologies that are described in the publications that might be used in connection with the presently described invention. The publications listed or discussed above, below and throughout the text are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior invention.

As used in the description herein and throughout the claims that follow, the meaning of “a”, “an”, and “the” includes reference to the plural unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the terms “comprise or comprising”, “include or including”, “have or having”, “contain or containing” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. As used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

In one aspect, as shown in FIG. 1, an improved coal gasification and purification system 100 may include a coal gasifier (110), a reaction zone (120) and a separation zone (130). In one embodiment, the coal is being heated without air to 900 to 1200° C. in the coal gasifier (110) to release the flammable gas and tars can be separated and collected from an opening coal tar outlet pipe (112) of the coal gasifier (110). It is noted that the coal gasifier (110) can be operated between 500 to 1500° C. In one embodiment, the coal is being heated by fire. In another embodiment, the coal is being heated by an electrical heater (115), which can be controlled by a feedback control system (400). More specifically, the temperature of electrical heater (115) can be sensed or measured by a temperature sensing unit (117), which is configured to transmit a signal regarding the temperature of the electrical heater (115) to a temperature control unit (119). The temperature control unit (119) is configured to control the temperature of the electrical heater (115).

In a further embodiment, the coal can be continuously fed into the coal gasifier (110) from the coal inlet (114). The flammable gas after passes the gas filter (113) has being transported toward the reaction zone (120) by a plurality of motors (116) while being gasified. In one embodiment, the speed of the motors (116) can be controlled through a feedback control system. A tiny one way air inlet (111) in the reaction zone (120) is provided to allow small amount of air to enter and react with certain harmful substances such as sulfur (S) to becoming sulfa trioxide (SO₃), and phosphorous (P) to becoming phosphor trioxide (PO₃) etc. And benzene, one of the flammable gas in coal hydrocarbons will react with sulfa trioxide to become benzenesulfonic acid (C₆H₅SO₃H). Also benzene will react with phosphor trioxide to become phenyl phosphoric acid (C₆H₅PO₃H).

The gasified coal then enters the reaction zone (120). The certain harmful substances such as sulfides, can be oxidized to SO₃ as shown in formula (i) below. And SO₃ can further react with benzene (C6H6) in the coal as shown in formula (ii) below, which is called a sulfonation process to generate benzenesulfonic acid (C₆H₅SO₃H), which can be fluidized and separated in the fluidized zone (130). After separated and isolated to add water to generate benzene (C6H6) and sulfuric acid (to be eliminated) as shown in formula (iii). It is noted, same as sulfides that phosphates can also be eliminated in fluidized zone (130), through a phosphoriation process as shown in formulas (iv) to (vi) below.

More specifically, the reaction zone (120) allows the harmful substances such as sulfides and/or phosphates etc. to react with air and benzene (one of the coal flammable gases), This reacting zone (120) provides a reaction space for sulfa and phosphate etc. with oxygen and benzene to remove harmful substances, and the gasified hydrocarbons can be fluidized, separated and collected in the separation zone (130).

The gasified coal then enters the fluidizing and separation zone (130) including benzenesulfonic acid, and phenyl phosphoric acid, which will be fluidized and separated because they have different boiling points. These harmful substances such as benzenesulfonic acid (C₆H₅SO₃H), and phenyl phosphoric acid (C₆H₅PO₃H) will be separated. The isolated benzenesulfonic acid becomes benzene (C₆H₆) and sulfuric acid (H₂SO₄) after water is added. The phenyl phosphoric acid after isolated becomes benzene (C₆H₆) and phosphoric acid (H₂PO₄) after water is added. The sulfuric acid and phosphoric acid can be eliminated, and benzene can be added back to coal hydrocarbons. It is noted that the purified coal may include various types of hydrocarbons, such as benzene, toluene, olefin, xylene, paraffin hydrocarbon, styrene, naphthalene, etc. with difference boiling points.

Sulfonation:

2S+3O₂=2SO₃  (i)

C₆H₆+SO₃=C₆H₅SO₃H  (ii)

C₆H₅SO₃H+H₂O=C₆H₆+H₂SO₄  (iii)

Phosphoriation:

2P+3O₂=2PO₃  (iv)

C₆H₆+PO₃=C₆H₅PO₃H  (v)

C₆H₅PO₃H+H₂O=C₆H₆+H₂PO₄  (vi)

As shown in FIG. 1, hazardous substances such as heavy metals, bitumen, coal tar, etc. can be eliminated from the coal tar outlet pipe (112). Various hydrocarbons, benzenesulfonic acid and phenyl phosphonic acid can be separated, and more importantly, during the fractional distillation process, the coal is fluidized and purified.

The main purpose of the present invention is to eliminate harmful substances such as sulfides and phosphates and etc. in the coal during the coal gasifying process, and further achieve the goal of a “complete” burning of the coal to significantly reduce pollution because after leaving the separation zone (130), the coal (or the hydrocarbons) is not only fluidized, but also purified.

Referring to FIG. 2 for a coal burning process, the fluidized hydrocarbons can be reheated to gasify hydrocarbons at position (151) and positively and electrostatically charged at position (152) of a first reaction chamber (210). Meanwhile, the air enters the second reaction chamber (220) connecting with the first reaction chamber (210), and the oxygen in the air is negatively and electrostatically charged at position (153) of the second reaction chamber (220). The positively charged hydrocarbons and the negatively charged oxygen can both travel to a third reaction chamber (230) to mix well with each other, and the hydrocarbon mixture can be burned with the oxygen in a fire place (240) to achieve the goal of the “complete” coal burning to reduce pollution since the harmful substances were removed in the coal fluidized process discussed above. In one embodiment, the fire place (240) can be heated up by hot water steam.

In another aspect, as shown in FIG. 3, a method for coal purification and gasification may include steps of heating the coal including various hydrocarbons and harmful substances such as sulfides and phosphates to 900 to 1200° C. in a coal gasifier in step 310; providing a reaction chamber with oxygen and connecting with the coal gasifier in step 320; the sulfides and phosphates in the gasified coal entering the reaction chamber from the coal gasifier and reacting with the oxygen therein in step 330; separating the mixtures of the harmful substances and hydrocarbons in the separation zone and collecting the hydrocarbons therein 340; Re-heating the fluidized hydrocarbons to a gasified form and positively and electrostatically charging the gasified hydrocarbons 350; and igniting negatively and electrostatically charged oxygen that mixes with the gasified and positively charged hydrocarbons to achieve a complete burning of the hydrocarbons 360.

In one embodiment, the sulfides in step 330 can be oxidized to SO₃ as shown in formula (i) above, and SO₃ can further react with benzene (C₆H₆) in the coal as shown in formula (ii) above, which is called a sulfonation process to generate benzenesulfonic acid (C₆H₅SO₃H), which can be eliminated as sulfonic acid after being separated and reacted with water, as shown in formula (iii). In another embodiment, same as sulfides, the phosphates can also be separated and eliminated in the fractional fluidized distillation zone (130) as shown in formula (vi) above in step 340.

As shown in FIG. 4, various of hydrocarbons burn in the fire place (240), in the exhaust chamber (250), produce a lot of carbon dioxide (CO₂). In the de-carbon dioxide section (260), calcium mono-oxide (CaO) is mixed with water, and the water level was kept by auto controller (161). When inside the section (163), the calcium hydrocarbonate (Ca(OH)CO₃) generated in formula (vii) in the section (260) arrives at a saturated level, a sensor may trigger an auto controller (164) to drain out the saturated calcium hydrocarbonate, and the new calcium mono-oxide mixed with the water will then be filled from water intake pipe (162).

In one embodiment as shown in FIG. 5, it is noted that formula (vii) is an exothermic reaction, and a heat exchanger (154) can be installed in section (163). The cold water can be provided from an inlet (155) and the temperature of the water can be increased when the water comes out from the outlet (156). As stated above, the fire place (240) can be heated up by hot water steam, and the water from outlet (156) is preheated, which can be used to heat up the fire place (240) so a predetermined amount of heat energy can be saved.

When the exhaust gas including carbon dioxide (CO₂) passes through the exhaust chamber (250) and a plurality of water pipes (165) of the de-carbon dioxide section (260), the calcium mono-oxide (CaO) mixes with the water will react with carbon dioxide to generate calcium hydrocarbonate (Ca(OH)CO₃), as shown in formula (vii). Most of the carbon dioxide (CO₂) will then be removed, and the rest of exhausted gas will be gone away from the chimney (166).

2CO₂+2H₂O+2CaO→2Ca(OH)CO₃+H₂  (vii)

In summary, coal in the solid form has to be heated without air to 900 to 1200 degree C. to squeeze out the flammable gas of hydrocarbons in a gasified form while eliminating heavy metals, bitumen, coal tar, etc. The gasified hydrocarbons are condensed and after eliminating harmful substances in the fluidized phase, the clean hydrocarbons, are saved in a fluidized form, which can be used as clean coal fossil fuel in the future. The clean fluidized hydrocarbon can be reheated at position (151) to be gasified and electrostatically charged at position (152) to become positive carriers to mix well with oxygen that is negatively electrostatically charged at the third reaction chamber (230) before burning. The mixture can then be ignited at the fire place (240) to burn to achieve completely burning. The calcium mono-oxide (CaO) mixes with the water will react with carbon dioxide to generate calcium hydrocarbonate (Ca(OH)CO₃), as shown in formula (vii). Then most of the carbon dioxide (CO₂) will be removed.

Having described the invention by the description and illustrations above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Accordingly, the invention is not to be considered as limited by the foregoing description, but includes any equivalent.

Claims

1. A method for coal purification and complete burning comprising steps of: (a) heating the coal in a solid form to a gasified form without air including various hydrocarbons and harmful substances to a predetermined range of temperature in a coal gasifier, and the temperature is controlled by a feedback control system;(b) providing a reaction chamber with oxygen and connecting with the coal gasifier;(c) separating the harmful substances from the hydrocarbons;(d) condensing the gasified coal from the reaction chamber to collect hydrocarbons in its fluidized phase;(e) heating the fluidized hydrocarbons to become a gasified form;(f) providing oxygen to mix with the gasified form of the fluidized hydrocarbons; and(g) igniting mixed hydrocarbons and oxygen to achieve complete burning.

2. The method for coal purification and complete burning of claim 1, wherein harmful substances include sulfides and phosphates.

3. The method for coal purification and complete burning of claim 2, wherein sulfides can be removed through a sulfonation process according to the formula below: 2S+3O2=2SO3  (i)C6H6+SO3=C6H5SO3H  (ii)C6H5SO3H+H2O=C6H6+H2SO4  (iii)

4. The method for coal purification and complete burning of claim 2, wherein phosphates can be removed through a phosphoriation process according to the formula below: 2P+3O2=2PO3  (i)C6H6+PO3=C6H5PO3H  (ii)C6H5PO3H+H2O=C6H6+H2PO4  (iii)

5. The method for coal purification and complete burning of claim 1, wherein carbon dioxide (CO2) generated in the coal purification and complete burning is removed through the formula below: 2CO2+2H2O+2CaO→2Ca(OH)CO3+H2  (i)

6. The method for coal purification and complete burning of claim 1, wherein the fluidized hydrocarbons are positively charged and the oxygen is negatively charged.

7. The method for coal purification and complete burning of claim 1, wherein the coal gasifier can be operated between 500 and 1500° C.

8. The method for coal purification and complete burning of claim 1, wherein the feedback control system includes an electrical heater, a temperature sensing unit and a temperature control unit.

9. The method for coal purification and complete burning of claim 8, wherein the temperature of electrical heater can be sensed or measured by the temperature sensing unit, which is configured to transmit a signal regarding the temperature of the electrical heater to the temperature control unit that is configured to control the temperature of the electrical heater.

10. The method for coal purification and complete burning of claim 5, wherein the step (g) of igniting mixed hydrocarbons and oxygen to achieve complete burning heat may include a step of using the heat generated by reaction (i) can be used in step (g).