Method for the treatment of granulated liquid slag in a horizontal furnace

Abstract

Improvements to the gasifier furnace design and process method to facilitate continuous production of mainly H.sub.2, CO and granulated solid from molten liquid or the liquid slag in the presence of carbonaceous material. It is a method of quenching molten liquid and cooling post quenched hot granulated solid which is done within a long horizontal reaction chamber space of the furnace in the presence of C and H.sub.2O. A moving layer of continuously gas cooled granulated solid protects the moving floor underneath by substantially reducing the possibility of heat transfer from the horizontal reaction chamber to such moving floor and its parts and preventing direct contact between the post quenched hot solid granulates and such moving floor. Such moving floor having plurality of gas passages and is disposed above a plenum that receives gas from outside source and uniformly distributes the gas to pass through all the gas passages.

Claims

1. A method of recovering thermal energy from a molten slag in a horizontal furnace with a moveable floor comprising: spreading a cold slag across length and breadth of the moveable floor to form a first layer on the moveable floor; spreading a carbonaceous material on top of the first layer to form a second layer; introducing the molten slag into the furnace and dividing the molten slag into smaller streams; spraying a quenchant to perform combined actions of fragmenting the smaller streams of the molten slag into a granulated solid slag and quenching the granulated solid slag to generate a horizontal draft gas; spreading the granulated solid slag over the second layer to form a third layer; and injecting a reactant gas from below the movable floor to create a upward draft reactant gas by the reactant gas reacting with the first, second and third layer; wherein the horizontal draft gas and the upward draft gas combine to increase residence time of the gases in the horizontal furnace for higher recovery of thermal energy from the molten slag.

Description

DESCRIPTION OF THE DRAWING

(1) FIG. 1 is a schematic cross section of the preferred embodiment comprising horizontal furnace (001) with a corresponding horizontal reactor chamber space (002) which is internally surrounded in the base mostly by movable floor disposed with plurality reactant gas injecting passages herein referred to as movable floor (003), insulated ceiling (004) and insulated walls (005) comprising:

(2) a plenum (006) to support the movable floor from below and to inject externally cleaned and cooled industrial flue exhaust (016) or air (016a) or their combination thereof (016b) into the reactor chamber space via inlet (007k),

(3) means (007) to prevent outside atmosphere air entering the reactor chamber from any inlet and outlet in the furnace other than through the plenum inlet (007k),

(4) Inlet (007a) to introduce a layer of externally cooled ambient granulated solid slag herein referred to as cold slag (008) or any other similar type of material, into the reactor chamber and spread across the width of the movable floor,

(5) inlet (007b) to introduce a layer of the carbonaceous material (009) or a mixture of carbonaceous material and flux material (009a) into the reactor chamber and spread above and across the layer width of the cold slag,

(6) inlet (007c) to introduce reactant (011) into the reactor chamber and spray (010) the reactant,

(7) inlet (007d) to introduce molten slag (012) into the reactor chamber space and a means to divide the molten slag stream into smaller streams and fragment (013) the smaller stream of molten slag by spraying reactant across the falling small stream,

(8) outlet (007e) to remove the mixture of hot solid materials (013) from the reactor chamber and such outlet located after the movable floor,

(9) outlet (007m) to remove the produced hot gas stream (014) from the reactor chamber, wherein the method and steps to produce hot gas stream (014) containing mainly H.sub.2, CO (014a) and hot mixture of solid materials (013) containing mainly granulated slag (008a, 017b) comprising;

(10) switching on the movable floor to move forward towards the outlet (007e) to remove the mixture of hot solid materials (013),

(11) injecting the reactant gas (016, 016a, 016b) into the plenum via inlet (007k),

(12) introducing the cold granulated slag into the reactor and continuing until such layer of the cold granulated slag (008a) covers the width and length of the movable floor and begin to exit the reactor chamber from the outlet (007e),

(13) introducing the carbonaceous material (009) or the mixture of carbonaceous and flux materials (009a) into the reactor chamber until such layer (009b) covers the width and length of the cold slag layer (008a) and begin to exit the reactor chamber from the outlet (007e),

(14) simultaneously introducing the reactant and the molten slag into the reactor chamber, divide the received molten slag into plurality of thinner streams, make them fall by gravity while spraying the reactant (010) onto the falling thinner stream and fragment thinner stream molten slag (017a) in the reactor chamber space to produce hot granulated solid slag (017b) and

(15) receiving the produced hot stream of gas (014) containing mainly H.sub.2 and CO (014a), hot mixture of solid materials containing mainly layer of cold slag (008a), layer of hot granulated solid slag (017b) and the layer of formed residue from the layer of carbonaceous material (009a) or the layer of the mixed carbonaceous and flux material (009b) for further downstream processing.

(16) The molten slag inlet (007d) of the reactor chamber connected to an outlet (018) of an externally located molten slag reservoir (019).

(17) Inlet (007f) to introduce gaseous or liquid or powdered solid carbonaceous material or their mixture thereof (009a, 009b, 009c, 009d) after the molten slag inlet (007d). The reactor chamber in between the inlet (007d) and the outlet (007e) is considered as reactor chamber space (002) wherein all thereto-chemical reactions occur.

(18) The first, second and third stage thermo-chemical reactions would occur above 800° C. throughout the reactor chamber space (002). This is based on Boudouard reaction and Ellingham drawing”. It states the formation free energy of carbon dioxide (CO2) is almost independent of temperature, while that of carbon monoxide (CO) has negative slope and crosses the CO.sub.2 line near 700° C. According to the Boudouard reaction, carbon monoxide is the dominant oxide of carbon at higher temperatures (above about 700° C.), and the higher the temperature (above 700° C.) the more effective a reductant (reducing agent) carbon.”

(19) Inlet (007g) to introduce and outlet (007h) to remove catalyst pellets or flux or carbonaceous material or the mixture of carbonaceous and flux material from the reactor chamber section are disposed after the reactor chamber space outlet (007e). This purpose is to expose the produced hot gas after the third stage thermo-chemical reaction to catalyst pellets or flux or carbonaceous material or the mixture of carbonaceous and flux material. This would potentially generate a hot gas stream with maximum possible concentration of either H.sub.2 or CO or their mixture with required H.sub.2:CO ratio from all the inputs. This would result from the thermo-chemical reactions occurring below 800° C. for example as in a Water Gas Shift process.

(20) Operational plasma electrodes and heat delivery torches or similar means (020) are disposed in the reactor chamber space to enhance the thermo-chemical reactions.

(21) The preferred embodiment can further purify the produced hot H.sub.2+CO or covert any remaining hot CO.sub.2 contained in such gas streams into CO. For this purpose, the hot gas is made to flow as downdraft through a bed of solid granulated carbonaceous material which is moved by the moving floor having plurality of gas passages. Alternatively, a layer of carbonaceous material is spread over a cold layer of moving granulated solid material. The hot CO.sub.2 gas react with carbonaceous material to produce CO and simultaneously get cooled during the process. The cooled gas is collected from the plenum underneath and is drawn outside the furnace from the exits located in the bottom of the plenum. In this case, there can be plurality of exits fitted with mechanical blowers and such exits distributed evenly across the length and width of the plenum bottom. This arrangement would facilitate the cooled gas being uniformly sucked into the plenum throughout the underneath of the moving floor having plurality gas passages.

REFERENCES

(22) 1. Experimental analysis of direct thermal methane cracking, 2011, A Abánades “Methane decarburation (MDC) is more energy effective than Steam Methane Reforming (SMR) and do not produce C.sub.2”. 2. A steam process for coal gasification, 1979, S. L. Soo et al, R. T. Gibbs et al “A high percentage of H.sub.2 can be produced in the product gas without the need for shift conversion”. 3. US20040265651, 2004, Meyer Steinberg et al “In the method of the invention, five technologies, known in the art, are combined in a single integrated process”. 4. U.S. Pat. No. 4,772,775, 1988, Sam L. Leach et al “Electrodes may initially form the arc plasma in air or other gas”. 5. U.S. Pat. No. 2,678,956, 1950, Hasche Rudolph Leonard et al “In high temperature thermal cracking, CH.sub.4 does more than reduce the partial pressure but also appears to function as an active agent”. 6. U.S. Pat. No. 7,914,765, 2008, Leslie C. McLean et al “continuously producing higher concentration of hydrogen in the finally formed product gas from the steam oxidation of molten iron (not from the molten slag) in multiple reactor chambers”. 7. Heat recovery from high temperature slags, Energies 2015, Y. Sun et al. 8. U.S. Pat. No. 6,196,479, 1999, Alfred Edlinger et al “Method and device for granulating and comminution of liquid slags and preventing oxyhydrogen explosion during quenching metal bearing molten slag with water”. 9. U.S. Pat. No. 3,298,822, 1967, William J Arvay et al “Method of making slag-based soil treatment composition comprising plant available phosphorus values”. 10. https://en.wikipedia.org/wiki/Ellingham_diagram