Title of Invention

''A CERAMIC BASED BIOMASS GASIFIER''

Abstract

A process for preparation or a ceramic based biomass gasifier characterized in that is: i) a ceramic inner shell, preferably cylindrical shape, outer metallic shell having any insulated material disposed between the inner shell and outer shell, ii) said ceramic inner shell is extend at its lower end into, the conical form which constitutes hearth portion of the gasifier, a feed preheater mounted on the top end of inner shell, iii) said ceramic shell having a composition comprising 35 to 65% alumina, 0 to 40% silica, 2 to 25% kaolin, 2 to 8% talc, 1-5% zirconia, 0-15% feldspar, being provided to withstand the high temperature within the gasifier.

Full Text

This invention relates to a ceramic based biomass gasifier. Biomass gasifier is a reactor vessel which converts biomass into producer gas and ash. High temperature of the order of 1300ºC is experienced inside the gasifier shell and this temperature i» attained within ten minutes from the start of the system. The gas generated in the gasifier is highly corrosive in nature. The gasifiers are usually made of high quality stainless steel and even that is not. withstanding the severe atmospheric conditions inside the gasifier and due to that life of the gasifier is very less. Main difficulty faced was to develop a design suitable for the conditions inside the gasifier without affecting the working and efficiency of the system. Therefore an object of this invention is to propose a ceramic based biomass gasifier which has a long life and work for a substantial period of time without any maintenance. Another object of this invention is to propose a ceramic based biomass gasifier which is of low cost in nature and the fabrication process is very simple. Yet another object of this invention is to propose a ceramic based biomass gasifier which increases the efficiency of the system. A still further object of this invention is to propose a ceramic based biomass gasifier which is thermal shock resistant and capable of withstanding high temperature. According to this invention there is provided a ceramic based biomass gasifier characterized in that is: i) a ceramic inner shell, preferably cylindrical shape, outer metallic shell having any insulated material disposed between the inner shell and outer shell, ii) said ceramic inner shell is extend at its lower end into, the conical form which constitutes hearth portion of the gasifier, a feed preheater mounted on the top end of inner shell, iii) said ceramic shell having a composition comprising 35 to 65% alumina, 0 to 40% silica, 2 to 25% kaolin, 2 to 8% talc, 1-5% zirconia, 0-15% feldspar, being provided to withstand the high temperature within the gasifier. Specifically in accordance with this invention, the inner shell has a ceramic composition of mainly alumina and silica as free or in compound form with other additional materials to get easiness in component formation, thermal shock resisting power by making porous body and as a sintering aid. The composition for the hearth has a high alumina in comparison to that of shell composition since temperature inside the hearth is very high. The shell experience a maximum temperature of 800°C only so the required alumina content can be brought down. The shape of the shell is cylindrical while hearth has a c on i ca 1 shape ( f r u s tu m) . The ceramic composition in according to this invention has alumina in the range of 55-65%. preferably 60-62%, Silica in the range of 25-35%. preferably 30-32%, Kaoline in the range of 2-4%, preferably 3-4%, Talc in the range of 2-8%, preferably 3-5%, and Zirconia in the range of 1-5%, preferably 3-4%. The ceramic inner shell is sintered at a temperature (preferably at 1400ºC) above the temperature experienced inside the gasifier. The different parts of the gasifier are made out of different ceramic compositions corresponding to the temperature experienced. The hearth where the temperature and the thermal shock is severe has been fabricated with better quality material as the other part shell is made of low quality material to reduce the cost of the system. A ceramic based biomass gasifier according to a preferred embodiment is herein described and illustrated in the accompanying drawings wherein! Fig.1 shows the sectional view of the biomass gasifier. Referring to the drawings ceramic based biomass gasifier according to this invention has a ceramic inner shell 1 preferably of a cylindrical shape, disposed within an outer metallic shell 2 having insulated material 3 disposed between the inner shell 1 and outer shell 2. The ceramic shell 1 is extended at its lower end into the conical form which constitutes hearth portion of the gasifier. The outer shell 2 is of the same size from top to bottom. Additional insulation layer 4 is provided around the hearth portion of the gasifier. A feed preheater comprising inner pipe 5 of the same diameter as of inner ceramic shell are mounted on the top end of said inner shell 5 portion of the gasifier and is disposed in the outer shell of the gasifier. An air-sealed cap 6 is provided at the top end of the inner shell 2 to cover the top end of the inner shell. The air sealed cap is used as a feed door. A water seal 7 is provided at the bottom end of the hearth 4 to prevent the leakage of the gas. A stainless steel pipe 8 welded to the bottom plate 9 is inserted to the water seal. A grate with a grate shaker (not shown) is provided to support the feed and also to remove the ash. A gas passage 10 with a doubled walled shell 11 for water cooling is connected with water seal 7. According to this invention the inner shell of the gasifier is made of the ceramic composition. The ceramic composition has 55-60%, preferably 60-62% Alumina, 25-35% preferably 30-32% silica, 2-4% preferably 3-4% Kaoline, 2-8% preferably 3-5% Talc and 1-5% preferably 3-4% Zirconia. In accordance with another embodiments the inner shell has a composition of Alumina in the range 50-607., preferably 54-56%, Kaoline in the range 15-25% preferably 18-20%, Feldspar in the range 5-15%, preferably 9—11%, Talc, in the range 2-8%, preferably 4— 6%, and Zirconia in the range of l-5% preferably 3-4%. In accordance with yet another embodiment, the inner shell has a composition of Alumina in the range 35-45% preferably 39-41% Silica 30-40%, preferably 30-32%, Kaoline in the range 10-20%, preferably .14-15%, Talc in the range 2-8%, preferably 3-4%, and Zirconia in the range 1-5%, preferably 3-4%. I CLAIMS; 1. A process for preparation or a ceramic based biomass gasifier characterized in that is: i) a ceramic inner shell, preferably cylindrical shape, outer metallic shell having any insulated material disposed between the inner shell and outer shell, ii) said ceramic inner shell is extend at its lower end into, the conical form which constitutes hearth portion of the gasifier, a feed preheater mounted on the top end of inner shell, iii) said ceramic shell having a composition comprising 35 to 65% alumina, 0 to 40% silica, 2 to 25% kaolin, 2 to 8% talc, 1-5% zirconia, 0-15% feldspar, being provided to withstand the high temperature within the gasifier. 2. A process for preparation or a ceramic based biomass gasifier as claimed in claim 1 wherein inner shells has a composition of Alumina in the range of 55-65% preferably 60-62%, Silica in the range of 25-35% preferably 30-32%, Kaoline in the range of 2-4%, preferably 3-4%, Talc in the range of 2-8%, preferably 3-5%, and Zirconia in the range of 1-5% preferably 3-4%. 3. A process for preparation or a ceramic based biomass gasifier as claimed in claim 1 wherein the inner shell has a composition of Alumina in the range 50-60%, preferably 54-56%, Kaoline in the range of 15-25% preferably 18-20%, Feldspar in the range of 5-15%, preferably 9-11%, Talc in the range of 2-8%, preferably 4-6%, and Zirconia in the range of 1-5% preferably 3-4%. 4. A process for preparation or a ceramic based biomass gasifier as claimed in claim 1 wherein the inner shell has a composition of Alumina in the range 35-45%, preferably 39-41%, Silica 30-40%, preferably 30-32%, Kaoline in the range 10-20%, preferably 14-15%, Talc in the range 2-8%, preferably 3-4%, and Zirconia in the range 1-5%, preferably 3-4%. 5. A process for preparation or a ceramic based biomass gasifier substantially as herein described.

Documents:

5-del-1999-abstract.pdf

5-del-1999-claims.pdf

5-del-1999-correspondence-others.pdf

5-del-1999-correspondence-po.pdf

5-del-1999-description (complete).pdf

5-del-1999-drawings.pdf

5-del-1999-form-1.pdf

5-del-1999-form-19.pdf

5-del-1999-form-2.pdf

5-del-1999-form-3.pdf

5-del-1999-form-4.pdf

5-del-1999-form-5.pdf

5-del-1999-gpa.pdf