Single vessel blast furnace and steel making/gasifying apparatus and process

Abstract

A blast furnace for use in an apparatus such as a steel making apparatus or a gasifier includes a vessel including a crucible. The furnace includes a lance for introducing fuel and oxygen into the crucible and instrumentation for determining density characteristics of molten material inside the crucible. In one embodiment, the blast furnace is able to adjust the input of fuel and/or oxygen into the crucible based on the measure density characteristics of the molten material. The blast furnace can also include structure for cooling and clinkering molten material discharged from the crucible.

Description

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/644,055, filed Jan. 15, 2005.

BACKGROUND OF THE INVENTION

This invention relates to the control of continuous and direct iron-making or gasification using ground coal, iron ore (where applicable), flux and other materials and unique sensors and computer control techniques and methods in a continuous gasification or smelting process through the judicious application of these specialized sensors and techniques to make an efficient and compact and less costly technology, whether making steel or syngas, that does not require people to interface with the process directly whereby they are needed only to keeping the lock hoppers full of feed ingredients, two lock hoppers are used for each ingredient to insure continuous and interrupted feeding of materials, and to keep equipment in good repair.

Much of present steel making is manually controlled with manual sampling of steel quality, manual control of molten levels within the furnace, long time lags, high expense of apparatus since coke and recuperator and other equipment not required of this invention are needed. Also, labor costs are higher with existing technology. Present steel-making apparatus, not being continuous, are not as well suited to recovery of slag materials, which is made easier with continuous and separately controlled molten slag and metal outflows, including metal recovery from the coal or carbon gasifiers if syngas is the product i.e. gasification of carbonaceous materials.

Present gasification apparatuses lack the simplicity of a molten bed approach plus the sophistication of the sensors and controls of the present invention. Existing processes are generally classified as fixed bed, traveling bed, fluidized bed, and entrained flow, and none of these processes has evolved into a market-leader technology.

DESCRIPTION OF RELATED ART

This invention relates to and improves on the inventions described in the inventor's previous filings, U.S. Provisional Patent Application No. 60/629,486 and U.S. Provisional Patent Application No. 60/635,117, by teaching less expensive and alternative methods of molten slag and molten steel layers level sensing and control. Whereas the referenced inventions show use of scanning nuclear or x-ray gages for this purpose, this invention teaches other lower cost proximity or point level instrumentation which when combined with sample-data control technique enables full control over molten slag and steel levels or thickness. Other alternative sensors that can be used are insitu laser spectrometers in the molten masses and other insitu point level sensors based on magnetic, capacitance, or inductive methods, and even floats, to sense molten slag and steel thickness. For example, the insitu laser spectrometer sensor can be used to control molten slag and steel levels or thickness because the material makeup is different for molten slag and molten metal, and such a sensor can determine this, but that sensor can also provide valuable composition information simultaneously and advantageously. Different signal characteristics will show up for the other types of point sensors mentioned for different materials present providing other means to control these levels or thickness. And when combined with instruments to sense the emitted gases can gain full control to optimize the gasification and steel-making processes. Which of these sensor types would be the preferred method is difficult to judge at this times since for some, like insitu laser spectrometers the costs will likely be high since they are not in use at this time, being a new insitu laser spectrometry invention, it is just being introduced such as the gas laser spectrometry sensor. However, these sensors have important advantages making their high cost fully justified for large machines. But this invention claims the use of these specialized sensors for the purposes set forth above and in conjunction with other technology cited in the references furthering the art and advances claimed by the inventor to achieve low cost and reliable syngas and steel-making technologies based on continuous processes and in particular using molten slag bed processes and technology for syngas producing purposes.

SUMMARY OF THE INVENTION

A continuous smelting/low-grade steel making process and/or coal or carbon gasification process and apparatus involving blasting a mixture of ground ore, coal, and a flux mixture(s) (or coal and flux and pure oxygen if a syngas gasifier) through a concentric water cooled downward lance close into the molten slag, with feed mix flowing between the outer cooled shell and inner core air blast tube which expels air/oxygen mixture at high velocity onto the top of the molten slag layer to make steel or syngas. Further, to make steel there is an air/oxygen blast under the molten metal layer from the base of the crucible distributed evenly through a fine bubbling diffuser mounted within the crucible floor so as to reduce carbon in the molten iron to make at least a low grade steel. For syngas making, ground coal or carbon and flux mixture is blasted into the molten slag with pure oxygen. Means to separately meter ore or gasifier mix ingredients from lock hoppers with bubble-tight valves with gas purging to prevent gas from flowing back though the hoppers, and with in-line mixer before entering the concentric lance with O2 or enhanced air-O2 mixture (steel). To preheat the air/oxygen blast for steel-making, circulates blast air mixture within a top metal plenum of the furnace with inner shell made of high temperature coated steel alloys enabling achievement of sufficient temperature air/oxygen blast. Slag and low-grade steel outlet trough with above laser spectrometer measurements or insitu laser spectrometer sensing slag and steel quality determining chemical composition of both slag and steel flows to enable optimization of steel quality and minimize carbon losses and control molten levels. Other means are presented to measure crucible molten slag and molten metal thickness to enable control for molten slag and metal thickness through an out-flow control valve. All this instrumentation is provided so as to combine and with suitable computer control and optimizing algorithms and software to properly control preheated ore mix feed rate and composition, levels of molten iron, air/oxygen blast rates, and all to produce a quality syngas or low-grade steel output with proper carbon, sulfur and potassium contents to the maximum practical extent so as to optimize steel making or gas quality within one vessel in terms of quality and production requirements and to maximize the overall cost effectiveness of process of gas making smelting and steel-making.

As a steel-making invention it is a simple, compact cost-effective technology designed to co-generate electricity and fully automate steel-making in a single vessel process and apparatus. The process also eliminates the need for coke and thus coking ovens, awkward air blast preheat apparatus, air pollution apparatus (since co-generation boilers handle all flue gas), all which makes steel-making compact and less costly with minimized pollution and maximized revenue capability.

This invention teaches use of a molten bed of slag to O2 or enhanced air/O2 blast in ingredients, simplifying operations and improving control while simplifying slag and metal (if present) rejection and recovery, or simplified steel-making. Advantages of this new gasification process and apparatus over present apparatus and processes are:

• • 1. Dry fuel feed. This means maximum hot gas efficiency potential, approaching 98% and minimized pure oxygen needed to gasify, minimizing oxygen operating costs.
  • 2. Due to the large molten slag bed mass, there is a flywheel-effect that helps keep the process going as a stable and intense reaction that can work for any carbon fuel, even the worst quality coals.
  • 3. The simplicity of the molten bath also seals off the drop leg of the contiguous hot gas cyclone cleaner, a critical advantage for both gasifying and steel-making since this cyclone hot gas cleaning is required to achieve low carbon loses and simplify downstream gas clean-up.
  • 4. Blasting fuel and oxygen into the slag mass splatters the slag onto the gasifer inner walls protecting the refractory and upper zone interior of the gasifier, which is a proven technique of the steel industry. This is critical to extending the life of the refractory for years of use between rebuilds.
  • 5. The ability to gasify any carbon material, even the poorest quality coal, is very important since many regions of the world do not have high quality coal. To do this, the control computer automatically adjusts feed ingredient ratios and oxygen blast and opens up the slag discharge valve more to let out the greater slag produced from the greater dirt in the coal or waste fuel. The new sensors and computer does it all automatically, including sensing and controlling the molten slag and/or steel bed thickness.
  • 6. It also has the ability to fully recover metals that sink to the bottom under the molten slag mass. A thicker metal bath is maintained if making steel.
  • 7. It also enables recycling slag into construction products. Since flux (limestone) is added as part of the combustion process to produce a cleaner gas to react out sulfur (if coal is used), and since flux is definitely added when making steel, the heat converts the flux into cement ingredients within the slag. So if the slag is air dried into clinkers and ground up and kept under cover like in cement plants, it becomes a concrete product base material useful to constructing buildings and roads, etc.
  • 8. It uses a simple feed apparatus which also enhances reliability.
  • 9. It uses new sensors and sophisticated controls to keep a close watch over all key process variables. Computer control is essential to optimizing and controlling basic process and is absolutely essential to maintain reliability and hands-off automation. The computer also enables software to be developed to optimize the process. This is a new standard of instrumentation being brought into steel-making and gasification processes to make them reliable and cost effective technologies.

To insure continuous feed, this process includes at least two (2) lock hoppers (not shown) for each ingredient of combination of similar ingredients such as ground coal, ore, and fluxes. Three for each ingredient provides needed redundancy for maximized reliability in feeding. These lock hoppers have specially designed variable speed flotation helical undercutting rotors, or the equal are also commercially available in the marketplace, to undercut and simultaneously unload and regulate feeds after calibration with rotary rpm measurement to flow to maximize production consistent with steel or syngas desired quality. More than one flux material lock hoppers may be added to control sulfur and phosphorous content of the final common-grade steel output for example. In gasification, a flux would be added if there was sulfur present in the carbonaceous fuel, such as in coal, and the lock hoppers would be evacuated of air before recharging with an un-reactive gas which also is easily removed later, such a CO2, whereby the feed lock hopper valve can be reopened and the now gas purged feed made to the ingredient mixer (not shown) commence. The lock hoppers would use bubble tight high-temperature valves on their inlet and outlet that are capable of hundreds of thousands even over a million operating cycles, such a valve made by Macawber Engineering Incorporated, which are especially suited to feed applications. To insure that no O2 or enhanced air with O2 blast (when making steel) can pass up into lock hoppers, to avoid possible dust explosions in the coal lock hoppers in particular when filling, they can be continually CO2 purged when feeding, as noted.

As noted, there is an in-line mixer (not shown) that feeds into the concentric water cooled lance entering through the center top of the steel-making furnace and/or gasifier. All ingredients converge by gravity flow or other means at this point for gravity flow into the molten slag mass through the water cooled copper lance of sufficient diameter to accommodate solid material flow in it's outer concentric perimeter and O2 enhanced air flow for steel making in it's center tube or nearly pure O2 blast flow if gasifying coal or carbonaceous materials into syngas. Iron is converted into common-grade steel in the lower molten metal zone by bubbling in oxygen and molten metal is discharged from a center tap hole on the center floor of the crucible. The exact location of the tap hole, which can be out the side as well, is not critical as long as it is below the slag layer about 12 inches.

The lance outer shell is water cooled with re-circulating water in the case making steel, or this flow is emitted as a radial water or steam from the lower end and perimeter of the lance spraying radially in a horizontal fashion from the bottom of the lance to create gasification reactions of ionized carbon into syngas. The amount of flow is governed by the syngas reactions measured by online sensors or the degree of cooling desired or both. The O2 blast tube in the lance center is shorter and inside the outer shell sufficient to create a venturi or suction effect to pull the coal or ore mix down the lance, and whereby the high velocity of the air/oxygen achieves thorough mixing and combustion of coal to smelt the ore and relying on the remaining molten slag and steel to finish smelting and conversion into iron or gas at the slag and upper region of the molten iron layer while impinging at sufficient velocity to push aside and splash molten slag onto the interior surface of the upper entrained flow volume of the unit. Pure oxygen is not as critical with steel making or where smelting operations are involved. In, gasification, to make syngas, pure oxygen is used in the blast and it's desirable to make the whole of the gasification vessel refractory lined and cyclone cleaner contiguous with the gasifying vessel in both steel-making and gasification. The gasifier or furnace pressure vessel outer shell is water cooled and further insulated against heat loss. Off-center and rectangular or elliptical housings are also feasible, thus concentric blast lances are not the only configuration possible to feed ingredients and blast and achieve a good result.

In steel making, the upper shell or plenum of the furnace has a high temperature steel alloy inner layer since pre-heating the air/oxygen blast is required to achieve steel making or smelting temperatures, such pre-heat temperatures are well known and will vary depending on the steel, coal quality or fuel and flux quality, but the upper plenum or shell area is designed with sufficient inner surface area of the exposed upper furnace to achieve these final blast temperatures at full load steel flow. Such inner steel alloy surfaces may be coated with ceramic or refractory for protection while still adequately pre-heating the steel air-O2 mix blast without exceeding safe operating temperature of the inner shell lining or outer pressure vessel shell. The outer shell of the pressure vessel is steel and water cooled but also insulated on the inside from the air-preheat flow preventing excess heat transfer into the water cooled outer shell by using refractory blanket or similar high temperature insulation or spray-on mixture, such detailed plenum layering and design is well known and understood by those skilled in the art of pressure vessel, furnace and heat exchanger design combinations.

Gases leave the furnace or gasifier through a water cooled and refractory contiguous cyclone as shown which cleans slag and/or carbon blow-by and returns it as molten slag into the crucible through the refractory lined and water cooled drop leg of the cyclone. The pressure drop through the cyclone causes slag to travel up into this leg an amount equal to the pressure drop. At 5 psi pressure drop through the cyclone, that rise is estimated to be about 4 feet above the average slag elevation in the crucible space. Also, such drop leg could be lined with inductive coil to re-melt solidified slag in the leg of the cyclone should that occur.

A refractory lined and insulated crucible below the upper air cooled metal portion of the furnace has a center bottom tap hole for finished common grade steel or to let out metals recovered from gasification operations, and a tap hole some distance above the floor on the side wall of the refractory crucible to accommodate slag removal, the height of this slag hole would be determined by design. For example, if for basic steel containing 600 tons were to be maintained in the crucible, the crucible inner diameter the slag tap hole may be as high as 6-7 feet. In the base of the crucible, there is a ceramic fine air/oxygen bubbler diffuser of sufficient diameter and flow to cause adequate carbon reduction in the iron in the lower section of the molten iron layer to convert smelted iron to common-grade quality steel, whereby such steel (or recovered metals as in gasification) flow down through an open center hole of this diffuser and tap hole passage or ceramic pipe, such ceramic passage hole pipe is a magnetic inducing coil or plates to produce counter forces for steel flow control to assist in the control of steel outflow for crucible molten level control purposes or melt material that might solidify in the tap hole. For gasification applications, the molten metal thickness, to the extent metal accumulates, would be much less than the molten slag thickness. The relative thickness as shown in FIG. 1 apply and is shown as if steel is being made.

To simplify discussion of the invention in this instance, a simple rectangular symbol is shown to represent steel and slag outlet valves for flow control which can be ceramic tubes surrounded with refrigeration coils to create hole size control or ceramic plug valve position or even ceramic flapper valve position outside the apparatus to control these flows. Or, ceramic plug valves can be mounted inside and actuated by suitable long ceramic shafts for outside actuators operating through flexible bellows interfaces (all not shown in detail) to enable pressurized operation of the gasifier. Any number of arrangements for metal and slag flow control are possible and are familiar to those in the business of designing and manufacturing steel-making furnaces, processes, and specialized steel ladle valve apparatus.

A reliable method to sensing of molten metal and slag or fresh feed accumulation in the previously mentioned U.S. Provisional Patent Application Nos. 60/629,486 and 60/635,117 was a scanning nuclear gage, or x-rays could also be used. An alternative to scanning focused nuclear emissions or x-rays to level thickness measurement is an array of insitu laser spectrometers, just invented by others. Such a spectrometer has been proposed and probably uses an air cooled diamond window to withstand the high temperatures (diamond melts at about 2.5 times molten steel temperatures, steel melts at about 1500 C). Indeed, 5 carat artificial diamonds of high quality are available and much larger artificial diamond crystals will be available soon. This is likely large enough a diamond crystal to pass a laser bean into and reflect off molten steel or slag for measurement purposes. The same laser can feed optic fibers to an array of diamond window insitu units with different fibers sending the reflected signal back to the same reading equipment and control room mounted sensor and computer (not shown). The advantage of the insitu laser spectrometer type sensor is it also feeds back the composition of the molten metal so that a picture of development into steel vertically within the crucible is obtained. One insitu laser spectrometer sensor for slag and one for metal could suffice for sample-data level control methods for slag and steel level. With this method, control valves increase output until slag level drops below the sensor whereby the flow is decreased and this oscillation up and down is part of the control method, which would be the same for the molten metal and slag interfaces. But if multiple levels are to be specified under different conditions, or to have working backups, or a full picture of steel quality development, an array of such sensors is needed. Three in slag and molten metal are shown, but many more can be used economically since the same laser and computer are used for every measurement. Such single data point level proximity sensors coupled with sample data-control theory have been common use before, and such control algorithms can accurately control slag and metal outflows to maintain their proper thickness while maintaining a relatively steady valve setting for any given load. Other types of insitu sensors can also determine a picture of density variation for layer thickness such as proximity probes that vibrate to determine densities, magnetic, capacitive or resistive proximity sensors, and the like. But of these, insitu laser spectroscopic sensors are the most powerful as to information gained by yielding also the quality state of molten slag or steel, especially carbon vertically within the metal molten mass. They can also be simple, rugged and long lasting if the window is a gas cooled diamond polished flat like a small piece of glass.

In addition, an alternative to insitu sensor array, a velocity change of a falling ball can determine levels of slag and molten metal as shown. This method of sensing velocity change is not as powerful a method as laser spectrometers, as mentioned previously and is an awkward method. In this instance, a heavier ceramic or water cooled ball is periodically released in the gas zone and hinged acting through a flexible diaphragm falls through an arc at various velocity rates depending if it were in gas, or molten slag or metal. Hence through velocity variations the computer knows where one interface starts and the other stops, thus determining thickness of these zones within the range of the oscillating ball. Or, two balls of different density to float on slag or steel could be applied instead. The computer algorithms to control these variables can be created by those skilled in the art of syngas or steel making and are discussed further below. Thus, with this critical level measurement and other measurements noted, the direct and continuous syngas or steel making processes and apparatus as explained herein can be fully automated and optimized.

Also, steel quality can be sensed as it flows molten and hot in the trough directly from the furnace unit (not shown). These laser spectrometer sensors to determine steel characterizes have been tried and found to be practical and is a back-up or adjunct method that can be used to continually sense final steel quality along with the insitu spectrometers mentioned previously and was covered in the cited inventions.

Insitu laser sensors are being tried now in the power industry to sense combustion gases and appear to be a practical method to sense steel making gases or syngas gases for more accurate control purposes. In situ laser combustion gas sensors do not need recalibration once calibrated. They do have to be gas purged to keep the optics cool, and this gas purge rate is accounted for in the calibration phase of the instrument. For gasification, CO2 or pure O2 would be the recommended purge gas. For steel-making, nitrogen would be the recommended purge gas. In the instance of making steel, control valve means to adjust air/oxygen blast rates into the top lance and bottom fine bubble diffuser and optimizing algorithms to computer control the whole furnace process as follows in A-G below:

A. If more production is needed, the computer looks to increase steel and slag levels or fresh feed accumulation levels to adjust to a higher steel and slag flows out enabling precise levels and thickness of metal and slag or fresh fed material accumulation to be maintained within the furnace or gasifier, and if final steel carbon is increasing per spectrometer measurements, it increases bottom bubbling air/oxygen flows. If CO is excessive, it increases the hot air/oxygen blast from the lance.

B. If steel carbon content too high, the computer increases bubbling air/oxygen from the base, and if that does not correct it, increases the lance air/oxygen blast as well. If it is still too high or reducing atmosphere in the furnace is getting too low (as evidenced by decreasing CO measurement), the ore mix feed is reduced or coal feed rate increased to bring the carbon reducing capability of the diffuser within it's acceptable range of capability.

C. For furnace molten iron level for any given ore feed rate (production set point), the molten layer sensing enables furnace iron level to be adjusted by the steel outlet tap hole plug position or refrigerant temperature or flow rate, eddy inducing restricting forces whichever means of flow control are used or necessary to be used. All three can be designed to operate in staggered way; eddy current first, refrigerant flow second, and use of the tapered plug force or position as a third method.

D. If steel is being made (with gasification, only carbon and flux would likely be added), the steel carbon level is acceptable, but other steel chemical parameters are too high or too low, the only remedy may be a change of the ore mixture by adjusting lock hopper discharge rates (lock hoppers not shown). It will take a long time constant for these changed to show up in the final steel since there can be up to 6 hours of steel capacity contained within the crucible for basic steel manufacturing operations (calcium carbonate used as flux), but computer control algorithms can easily accommodate such time lags given the level inputs.

E. The laser spectrometer on slag monitors it for iron and carbon content indicating an ore mix change may be needed or that more lance blast is needed. It may be desirable to let out-of-limit carbon conditions prevail in the slag if it is the most cost effective operation. The computer can be capable of calculating the cost consequences of various operation modes. As noted, this laser spectrometry is shown insitu, or lasers can sense the molten outflow itself as shown in the previously mentioned U.S. Provisional Patent Application Nos. 60/629,486 and 60/635,117.

F. Since it's probably almost always desired to evolve to maximum possible production capability of the furnace, the computer can always be set to an evolutionary operations standard of maximum production, say as determined by an upper level carbon content of the final steel or iron or slag or maximum syngas flow (hot gas mass flow rate measurement method not shown). In this instance, the computer will slowly ramp up input or mix feed rate and adjust crucible molten slag and iron levels to maximize production. Maximum possible levels of slag and iron will be determined over time. Increasing top air/oxygen lance blast and bubbling O2 rates under the steel should maximize steel production until a limiting condition is reached (say excessive carbon in the final output steel) then the computer will back down production to within a safe level such that there is a measure of control over the process using the various parameters measured: water vapor, O2, CO2/CO, temperatures, final laser spectrometer quality measurements of steel and slag, furnace iron and slag level or thickness, air blast, air/oxygen bubbling rate, or ore mix compositions, steel and slag flows, syngas flows, all automatically adjusted by the computer control system algorithm determinations.

G. Steel and slag weir flows (not shown) are measured since they indicate production levels of actual steel and slag and they can also indicate if an upper limit has been reached or that there are molten steel or slag flow control problems. For example, if the plug opens the tap hole more but no increased flow is noted in either slag or steel, then ether the flow control actuating methods are failing, and computer historical data can immediately enable the computer algorithm to alarm, and output what the operator should check first.

Thus, it can be seen that this invention teaches a very advanced method of continuous steel making and/or gasification and uses the most modern combination of instruments and sensors to accomplish this, and it teaches a variety of molten slag and steel level and quality sensing instrumentation that can be used, and unique arrangements of equipment and process to avoid the need for coke and expensive recuperator to preheat air/oxygen blast to proper temperatures. And finally, optimization algorithms are suggested such that those skilled in the computer programming arts and steel-making and syngas making in combination with steel process engineer experts in acid or basic steel making processes etc. could enable such software to take advantage of the instrument signals provided to gain precise and accurate control over the process including ingredient mix ratios and all material flows to optimize syngas and steel outflow rates with maximized quality and economic advantage with a minimum of labor input and capital cost.

Finally, means are suggested whereby maximum recycling of slag wastes into useful building materials is possible by air drying slag into clinkers, and grinding these clinkers into cement base material with crystallized dirt already present, and adding what regular cement product is necessary to make a quality pre-mixed concrete aggregate based product.

The present invention and its advantages over the prior art will be more readily understood upon reading the following detailed description and the appended claims with reference to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the concluding part of the specification. The invention, however, may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:

FIG. 1 is a vertical schematic section of one embodiment of the present invention.

FIG. 2 is a vertical schematic section of another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views, FIG. 1 shows an apparatus 1 comprising a single vessel blast furnace that can be a direct smelting iron and steel-making apparatus or a gasification apparatus. Generally, the present invention relates to any type of apparatus that produces a molten by-product, such as molten slag or ash, including, but not limited to, iron or steel making apparatuses, solid waste, coal and other types of gasifiers, waste-to-energy boilers, and coal boilers.

When apparatus 1 is used as a gasifer, it's desirable to keep nitrogen out of the gasification reactions to avoid noxious nitrogen based compounds, therefore once lock hoppers (assemblies with valves not shown) are filled, it's desirable to close bubble tight lock hopper valves and evacuate the chamber by vacuum pumps (not shown) and continue to purge lock hopers with an un-reactive gas such as CO2 to re-pressurize the lock hoppers so as to prevent undesirable gasification reactions when oxidizing reactions take place from pure pre-heated (if necessary) oxygen or air-oxygen mixture addition 2 through lance 3 inner O2 feed tube 4 (shown as a line in FIG. 1). At least 3 hoppers per ingredient provides the maximum practical reliability. It should be noted here that the terms “air” and “oxygen” can be used interchangeably and either term, whether used alone or together, refers to air, pure oxygen or any other oxygen-containing substance.

Also, in feeding coal and flux or any material mix 5 to be gasified, it should be relatively dry and finely ground material, but it does not have to be a fine powder, as pure oxygen is highly reactive with carbon under circumstances depicted in the invention. Therefore, as in times past when coal was prepared (ground) and stored in large bins prior to feeding to boiler burners, for best feed reliability this is also a better practice for this invention utilizing large storage silo's, for example, before feeding coal to fill the lock hoppers (not shown).

Mix feed 5 (coal, ore, and fluxes respectively) flows by gravity through chutes (not shown) into the outer concentric space 7 of lance 3 splitting around inner lance air/oxygen tube 4 (shown as line here). Lance 3 can be as large as twenty-four inches in diameter or more for furnaces with 800,000 tons per year of steel producing ability. Also very high output gasifiers are possible with this design, as large as 1000 MW input and possibly even double that coal feed rate as a gasifier should be feasible since at inputs of 1000 kW/cubic foot (less than one horsepower input per cubic inch) are feasible, that's only an entrained flow volume 6 above the slag layer of 1000 cubic feet with a coal flow of about 130 tons per hour (depending on coal BTU content). The well insulated gasifier 1 is expected to achieve a hot gas efficiency approaching 98% (neglecting parasitic losses, the largest being O2 production).

In describing the upper furnace area, in making steel, blast 2 enters the bottom of upper plenum dimension area 8 at 2″ (plenum details not shown) passing around this plenum to pre-heat the blast and cool the plenum whereby it enters to enter lance 3 as blast 2 or pure oxygen blast 2 if making syngas. Note for steel making, blast 2 is not 100% oxygen but is only pure oxygen enhanced and pre-heated as needed to achieve high temperatures to smelt the ore mix. Similarly, when apparatus 1 is used as a gasifier, upper plenum area 8 may be fully refractory lined as shown for crucible lining 9 in molten slag 10 and molten metal mass 11 spaces. If the unit 1 is a gasifier, molten steel thickness 11 will be held to a much lesser thickness than slag thickness 10. Mix 5 leaves the lance as 5′ as shown to combust and or smelt into iron on the top layer slag 10 which is depressed as shown due to the high blast 2′ velocity leaving the lance 3 tube 4. Oxygen blast 2′ which is slightly inside the lance perimeter exit mouth as shown, which creates a vacuum to induce mix 5′ into the burning and/or smelting zone 12 beneath the lance insuring complete mixing of mix 5′ and oxygen blast 2′. Lance coolant 13 enters the cooled perimeter of the lance, generally of copper construction, (water coolant flow control not shown) as shown and if making syngas exits at the base as 13′ around the lower perimeter of copper lance 3 through nozzles (not shown) which along with pure oxygen 2′ makes unit 1 into a syngas producing device instead of a smelter/steel making device, otherwise, coolant 13 re-circulates through the lance as required to keep lance 3 within temperature specifications.

Water cooling details of externally insulated outer shell of apparatus 1 are not shown, but such technique is well known to those skilled in the art of such pressure vessel design including hoop stress design criteria for such high temperature pressure vessels, including insulating this outer shell inside the area 8 if it is a plenum preheating air-O2 blast in the case of making steel. As a steel making device, the upper shell area 8 of apparatus 1 would likely require a separate controlled coolant should the complete unit 1 not be fully refractory lined as in making steel. For example, when making steel, upper plenum shell area 8 is designed as a plenum to preheat oxygen enhanced blast 2, whereas when gasifying, such a blast preheat plenum is not necessarily required (although it may be desirable in some instances, say with wetter fuels) so the whole inside area 8 of upper entrained flow zone 6 could be refractory lined. The outer shell of unit 1 as a pressure vessel would still be water cooled and further insulated to minimize heat losses as noted above. The inner shell of plenum area 8 could be any corrosion resistant metal but would probably be stainless steel and ceramic or refractory spray coated for further protection but of not such thick layer as to prevent adequate air-O2 mix preheating for steel making. The inner or part of the other pressure vessel of area 8 would also be insulated to preserve the pre-heat value of the blast.

The preheated air/oxygen blast 2 through center tube 4 impinges into the molten slag 10 at zone 12 combusting the coal or carbon material providing heat for smelting or gasification as required. This blast also spatters slag (not shown) within the upper zone 6 which helps preserve the inner shell coating material of plenum area 8, and passes down through the concentric opening by gravity to impinge onto and create a depression of the molten slag 10 created by the force of air/oxygen blast 2. Typically about ten psig of air pressure would be used to create the high velocity blast 2′ needed including pressure drop needed to clean gases through a cyclone 14.

Inner gas flow 15′ whether from steel making or gasification passes into the refractory lined and water cooled cyclone 14 to remove molten particulate matter or slag to recycle it back as molten material into slag mass 10. The high temperatures keep the carbon and escaping slag into a melted state as noted and which runs down leg 14′ back into molten slag mass 10 as noted. Since there is a pressure drop though cyclone 14, slag 10 is drawn up into leg 14′ to some level 17 approximately as shown, but such amount will vary depending upon the pressure drop designed into the cyclone 14, but about 4 feet of elevation into leg 14′ above the average slag mass 10 top level would be expected for a 5 psi pressure drop.

And to complete gasification reactions if no iron ore is being added but just coal and flux as in gasification, the water cooled outer layers of copper lance 3 of would emit coolant stream 13 as steam water/steam mixture 13′ though nozzles (not shown) around the lance perimeter at it's base to complete the gasification reactions to hydrogen and carbon monoxide with some excess water vapor present along with CO2 and vaporized or ionized trace metals, and H2S and other vaporized compounds and elements which are removed later from gas 15 by well known methods. The amount of steam or water 13′ emitted from periphery nozzles on lance 3 will depend on the gas characteristic measured and temperature of the reaction desired and whether blast 2 is mostly air or mostly pure oxygen, but is generally minimized. Better control of either steel or gasification burn reactions can be achieved in gas 15′ or final gas 15 by using new laser spectrometry emitter 19 and receiver 19′ technology which shoots a laser beam 20 across and through a chord segment(s) of gas stream 15′ or 15 (multiple units would be used in an array to get a complete picture of the gas within space 6 but only one of 19/19′ is shown) as gas 15 in the exit pipe (lasers not shown). Only about ½ of 1% of beam 20 needs to strike sensor 19′ to record nearly all the gas 15′ characteristics including temperature, moisture, CO, CO2, O2, and other gas constituents. Because this measurement is laser based, once it is calibrated, it should never need to be calibrated again, which is a distinct advantage over all other hot gas sensors to determine gas characteristics. Conventional gas constituent sensor 18 would also be installed as a back-up and calibration check on spectrometer assemblies 19/19′.

The lower furnace area is comprised of refractory lined crucible with insulated refractory 9. The inner diameter of this crucible material 9 could be as large as 20 feet inside diameter to accommodate say 600 tons of steel maintained in the furnace for basic steel operations for a 800,000 tons per year furnace. To control upper molten slag level of mass 10 and molten steel level of mass 11, a scanning nuclear or x-ray gage operating along a vertical chord of the crucible lined as 9 from the outside (not shown) can be used and is described in the previously mentioned U.S. Provisional Patent Application Nos. 60/629,486 and 60/635,117. These would not generally scan through the center of the diameter but rather off to one side as noted, or scanning a chord of the crucible's horizontal cross section of suitable length for nuclear ray penetration through the furnace and furnace mass to detect the full range of molten slag 10 and steel 11 respectively, and upper fresh feed mass thickness as well (fresh material thickness not shown). This signal is feed into a computer programmed to show a complete vertical density profile of the vertical height measured which can be used to make control decisions on inflows and outflows to the furnace to be discussed below. Other sensors that can accomplish this control task are discussed below and which have certain other advantages.

The upper layer of the molten steel molten mass 11 is expected to be considered as smelted iron and the lower level of 11 to be low-grade steel created by the carbon reducing action of an oxygen blast 22 which passes into the base of the crucible 9 through fine bubbling diffuser 23 and up though the mass of molten steel and slag as shown depicted as bubble streams 23′.

The common grade steel 21 exits the base of unit 1 through ceramic pipe passage or tap hole 33 which through most of its length is surrounded by eddy current inducing forces coil not shown which can be activated by electricity so as to act as a countervailing force to control the exit flow of steel 21 through passage way 33. The outer tap hole area 33 is surrounded by refrigerated coil (not shown) which can have cooled fluids at various flow rates and temperatures, adjusted by computer control based molten steel level computer inputs to cause the exit tap hole 33 to shrink in size as required which can also control out-flows of steel and slag and the level or thickness of 10 or 11. Similar technique can be used on slag tap hole 24″. Or, the computer can activate the actuator of plug valves 24′ for slag and 21′ for steel, such ceramic plug flow valves are well known in the steel making art and are usually submerged in a pan (not shown but depicted in cited inventions).

To begin operation of the furnace or gasifier, molten slag would be added to the crucible though an upper furnace opening (not shown), and then the hot blast 2 would commence in conjunction with the feed 5 driven by blast 2 into the slag as 10. The computer would be determining the amount of moisture, temperature, CO2, CO, and O2 of the process gas 15′ and exit gas 15 and begin to adjust feed rate 5, slag and steel flows 24 and 21 respectively and starting the adjustments of mix 5 ingredient ratios or rates depending on insitu laser spectroscopic measurements 26 (three sensors shown) and 27 (three sensors shown but a full vertical array on the steel mass would likely be used). Other types of insitu proximity sensors can be used to replace 26 and 27 to determine different density characteristics of molten materials such as molten slag 10 and metal 11 including vibrating probes, conductive and capacitive sensors, magnetic and the like. Even the dropping ball sensors 28 (shown in raised position 28′) hinged at flexible diaphragm 29 could have a combined actuator velocity sensor 30 to determine velocity change and hence the interface location between gas in 6 and slag 10, and the interface between slag 10 and molten metal 11 and in so doing know the positions of these interfaces. An insitu laser spectrometry sensor (details not shown) as in 27 could also be attached to such an oscillating ball 28 to sense constituent elements of slag 10 and steel 11 as ball 28 is moved through slag 10 and steel 11 and passing the fiber optic signals into and out through a hollow arm of 28. Even multiple floats (not shown) like ball 28 designed to float on the slag and steel interface layers respectively with units 30 designed to determine floating position could be used. Those skilled in the art of applying such specialty sensors will know the most cost effective and reliable combination of such instruments. The previously mentioned U.S. Provisional Patent Application Nos. 60/629,486 and 60/635,117 illustrate reliable and preferred methods, and this invention illustrates other preferred devices, like insitu laser spectrometers, that can sense molten slag 11 and molten metals 10 depths and quality and which by virtue of their design characteristic of using a single emitter and sensor at the computer and fiber optics to a variety of units are possible, including exposed outflows of steel and stag. It is believed laser spectrometry as detailed here will eventually be very cheap and powerful sensing technology for these purposes applying many such sensors simultaneously to these processes.

Because there is such a long time constant for turnover of steel 11 within the crucible, about 6 hours, previous data and experience in steel operations contained within the computer data base, plus known experience and nuances about steel making programmed into the computer, enables quite accurate initial conditions for all the control variables to be set such as pulverized coal, flux, and ore ratios to the total mix 5 and what blast 2 is appropriate for what total feed mix flow 5 selected. The final measurements of the laser spectrometers and outlet gas 15, of CO2, CO, and temperature and other gases will enable the computer to bring the whole process under control and then fine tune the process for best steel quality consistent with carbon losses in the molten ash and needed production level.

If more production is needed the computer looks to see if it can increase steel 11 and slag levels 10 and if it can, increases the steel 11 and slag masses 10 in the crucible 9, and then it adjusts to a higher slag and steel flows 24 and 21 respectively. And if final carbon is increasing per insitu laser spectrometer measurements 27 or external laser spectrometer (not shown) that measures steel quality, it increases bubbling air/oxygen flow 22 and if CO is increasing, it increases the hot air/oxygen blast 2.

If the steel carbon level is acceptable as measured by steel laser spectrometer 27, but other steel chemical parameters are too high or too low, a remedy may be a change of the flux mixture of 5. Because there may be up to 6 hours of steel production retained in the crucible 9 for basic processes, it will take a long time for these changes to show up in the final steel 21, but it is still capable of automatic control and optimization by the computer since the computer clock can wait these intervals to check final results from the spectrometers.

If the laser spectrometer 26 used on slag indicates an ore mix 5, ratio change may be needed or that production can be increased, under blast 22 is increased to reduce slag carbon content. Or it may be desirable to let slag carbon go out of limit to achieve the production level desired. Those skilled in the art of steel making will enable the computer programmer to fine tune the logic to optimally control the process.

Since it's almost always desired to evolve to maximum possible production of syngas or steel, the computer can always be set to a evolutionary operations standard of maximum production say as determined by an upper level steel 21 carbon content. In this instance, the computer will slowly ramp up input feed 5 and adjust slag and steel mass levels 10 and 11 as noted to higher mass levels in the crucible 9 while increasing top blast 2′, mix feed 5, and bubbling blast 22 until an upper limit of any one of these parameters is reached such that it is then known steel 21 carbon content will start to rise or gas quality starts to fall as determined by CO and CO2 contents, then the computer will back down production to within a safe production level such that there is a measure of control over the process using the parameters of CO2/CO, final spectrometer measurements 27 and 26 of steel and slag respectively or laser spectrometers pointed down onto the trough flows of slag 24 and steel 21 (lasers and troughs not shown).

Steel and slag weir notch flow levels (apparatus not shown) are measured with a proximity level device (not shown) such as a non-contacting radar or fluidic sensor can measure production levels of actual steel 21 and slag 24 which can indicate an upper limit has been reached or that flow controls are malfunctioning. For example, if the plug opens the tap hole more but no increased flow is noted in either slag 24 or steel 21, then ether the tap hole is too small, the plug is malfunctioning, or a limit has been reached, and computer historical data can immediately enable the computer algorithm to manage a determination and alarm output which the operator then evaluates. All of the various sensor measurements can be programmed to alarm if extremes in their condition are reached.

Other variations of the invention are possible, such as rectangular, elliptical cross section shapes for gasifier 1 and with lances 3 to one side and feed into lances on one side and blast tube 3 the other with blast to one side and ingredients to the other and various configurations for steam and water blast for gasification (not necessarily a symmetrical blast 13′ from the lance 3 itself). But the previous description is a least cost and most compact or volumetrically efficient way to make the invention for an integrated syngas and/or steel making operations. And in steel-making, unit 1 is used in conjunction with a sizable power boiler (not shown), such boiler having several other large pulverized coal burners added to enhance profits from power operations, while the power boiler fully cleans up the emissions from steel making through the boiler's comprehensive emissions reducing apparatus on the boiler stack gases. The present invention is capable of a completely hands-off automatic control over the steel-making or syngas making process in a cost effective manner. It's intensity of operation and process and apparatus arrangement achieves a compact technology, as noted, and minimized capital cost apparatus. For steel-making it doesn't require expensive coke to operate, only cost-effective ground-up coal either as a gasifier or a steel-making.

Referring now to FIG. 2 a second embodiment of the present invention is shown. This embodiment relates to any type of apparatus that produces a molten by-product, such as molten slag or ash, including, but not limited to, iron or steel making apparatuses, solid waste, coal and other types of gasifiers, waste-to-energy boilers, and coal boilers. However, by way of example and for purposes of illustration, FIG. 2 depicts a gasifier. As such, it doesn't describe the scanning nuclear gage described above, as it only needs to be a fixed slag nuclear gage sensing molten slag level over definite and limited range of levels. And there are no multiple outlets of slag and steel in a simple gasifier, just a single slag outlet should generally be needed. However, if there were a lot of metal in the coal feed, the gasifier crucible could be arranged to be like a steel-making one with multiple molten outlets with material separation generally depending on density difference and accumulating layers of different materials which would require a scanning nuclear gage in this instance to enable individual control of the out flow rates. But the resistive heating or other methods of heating of the crucible molten material and other machine elements shown apply to both steel making and gasifier as does the slag recycling apparatus achieved through cooling and clinkering described herein. Thus, no other specific references to steel making will be made in the following description.

Referring to FIG. 2, a gasifier 1 is shown as a low pressure unit and thus represents a simple, low cost version of a gasifier. This gasifier is made low cost in part by using a simple low pressure (e.g., about 20 psig) air-lock rotary feeder 2. For higher cost high-pressure versions, multiple lock hopper feed units with unloader/feeders (not shown) would be substituted for feeder 2. But overall, a high pressure version would still be more economic than existing gasifiers due to savings in slag discharge apparatus and more accurate control possible through advanced sensing and this invention's dry feed process design.

Dry fuel mixture 4 is fed through rotary feeder 2 down though the inside of cooled copper lance 3 (copper feed lances are common in the steel industry to inject gases and fuel into smelting and steel-making operations) as fuel 5 falls by gravity and is blasted atop the slag mass 6. This molten slag mass 6 also provides a “fly-wheel” effect to levelize the effects of variations in fuel quality to gasification, a common problem with boiler burners. Air blast 7 cleans the materials from the feeder compartments and provides a purge of air or oxygen for the inside 8 of lance 3. It should be noted that fuel 4 can be a wide range of fuel quality, such as municipal solid wastes. Various fluxes can be added with the fuel 4 to remove sulfur and other metals and can be adjusted accordingly.

Lance 3 has air passages 9 to take air or oxygen oxidizer blast 10 to the base of the lance as blast 11 angled across the incoming fuel flow to cause through mixing of the feed 5 and oxidizer blast 10 around the lance periphery which creates a very hot fire at 12 atop the molten slag mass 6 in the 2650 F range or at least to the limestone calcination temperature of about 2650 F to insure that any lime flux added with fuel mixture 5 is reacted to reduce sulfur in the burning fuel whereby the calcium ions Ca react with the sulfur ions S to form CaSO4 or calcium sulfate. Quicklime CaO is also formed from Ca un-reacted with S and comes out in the slag discharge 13. To control the carbon content of slag discharge 13, fiber optic laser spectrometry sensor 13′ can bounce signal 13″ off slag flow 13 and that carbon content signal can be used to control the rate of oxidizer bubbling 26. More about fiber optic laser spectrometry sensing will be discussed later for control of the gasifier.

The outside of lance 3 is water or steam cooled by concentric passageway 14 through which water or steam 15 flows which is emitted radically from the lance perimeter and shown which reacts with the fire passing up though entrained zone 16 to cause gasification reactions within the entrained flow zone known as 12 and 16. Final entrained flow gas and ash and slag particles 18 leave entrained flow zone 16 to be cleaned in primary hot cyclone 17 and leave as hot gas 18′. If blasts 7 and 10 are pure oxygen, gas 18′ will be classified as a syngas and be principally hydrogen and carbon monoxide with a small amount of CO2 and other trace gases. If blasts 7 and 10 are air based, gas 18 will have a lower Btu value and be like a producer gas. Low Btu gas is most economic for boiler power applications where the extra volume due to nitrogen present in the gas is not a problem. Thus much less apparatus is needed as no expensive air separation unit is required. Well insulated and water cooled on it's outer skin, gasifier 1 can have a high hot gas efficiency up to 98%. Thus, close coupled to boilers there is no power efficiency loss due to gasifying first, yet the boiler can run much cleaner throughout its operating life reducing maintenance and soot blowing.

Ash and slag captured by cyclone 17 passes down the cyclone leg 19, which is shown with embedded electric heaters 20 which are also in the walls of the cyclone 17 as well to insure the ash stays molten should temperatures fall below slagging temperatures. The electric heaters 20 can be any suitable heating means such as resistive or induction heaters. Depending on the pressure drop through cyclone 17, molten slag 6 in crucible 21 will be drawn up into the cyclone discharge leg 19 to a level 22, about as shown, i.e., the molten slag bed 6 is in effect the seal for the cyclone discharge leg 19. This unique sealing method is advantageous because it makes hot gas cyclone 17 maximally effective in cleaning gas. About a 5 psi pressure drop would be ascribed to cyclone operations to insure a properly cleaned gas 18′ before sending the primary cleaned gas on to other operations, which could be to boiler furnace combustors or syngas cleaning and conversion operations.

The gasifier temperature and oxygen/coal or carbon ratio is measured through appropriate flow measurements devices which can be the speed of the feeder 2 or orifices on blasts 7 and 10 respectively (not shown) and controlled by adjusting fuel feed using feeder 2 speed and blast based on gas temperature and gas constituent measurements as measured by fiber optic laser spectroscopy shown as emitter 23, laser beam 24 and receiver 25 located in the upper area of the gasifier 1 and/or emitter 23′, laser beam 24′, and receiver 25′ located in exit pipe 26′. The lenses of these beams are air or O2 purged (not shown) depending on which blast gas is used, or some combination blast. The sensing and control computer is not shown but the whole apparatus would be as made by ZoloBOSS or equal and generally up to eighteen or so points across the entrained flow zone 16 (only three such sensor combinations are shown) can be sensed and measured by the computer simultaneously using sample data control techniques including. This for example, should it be desirable to run the gasifier entrained flow region 12 and 16 highly reductive atmosphere there, that is a heavily soot gas 18 prior to cyclone cleaning, fiber optic laser emitter 23′, beam 24′ and receiver 25′ cleaned gas 18′ exit pipe 26′ would be installed. However, because so many points are available from the ZoloBOSS system, exit gas 18′ would always be measured in any event since it's gas constituents and temperature and moisture measured by emitter 23′, beam 24′, receiver 25′ are adequate to control the gasifier if zone 16 laser units become fouled with soot. Also, a heavily carbonaceous soot gas 18 may be desirable from an emissions reduction standpoint to absorb heavy metals and the like, including mercury. Salts can also be added with fuel feed 4, for example, to ionize elemental mercury for easier scrubbing within the stack gas clean-up system of a boiler.

Only about ½ percent of the emitted laser light 24 needs to reach the receiver 25 to measure gas constituents. Thus, dirty gas streams within gasifiers can be measured with this technique, and according to the manufacturer, laser spectroscopy never has to be recalibrated as a measurement technique once set up. And depending on the laser used, it measures CO2, CO, O2, moisture, and combustion temperature. Thus, if the temperature is too low, the blast 10 can be increased to produce more complete combustion and thus hotter conditions in zone 12 which also produces more CO2 in the final gas un-cleaned gas 18. Thus if the CO2/CO ratio is too high, the oxygen/coal mass ratio can be adjusted down. But because of the dry fuel feed and comprehensive sensing and controls, these measurements enable the control computer to fine tune operations to minimize CO2 in the final cleaned gas 18′. And the close coupled cyclone 17 will take out any ash and slag blow-by 17′ and recirculate it to the crucible slag mass 6. Similarly, excess carbon can be spectroscopic sensed in the final slag 13 as noted, the computer can then increase oxidizer rate 26 through ceramic bubbler distributor 27 as bubbles 28 to react any excess carbon in the slag discharge 13.

Slag flow control out can be by a ceramic plug valve 29 as used in the steel industry or by refrigeration coils 30 used to freeze the tap hole 31 smaller, or let it melt to a larger tap hole as required on the discharge end of discharge tap hole 31 as noted. This slag outflow 13 is controlled to maintain a constant slag level 6 and is controlled by typical fixed and inclined nuclear level gage generally comprised of emitter 32, nuclear ray 33 and receiver 34, such control systems well known in the art, that is 33 signal received gets less as level increases so valve 29 is opened to bring the level back down or the opposite logic is also true. With refrigerant 30, if the level of 6 increases, less refrigerant flows and the tap hole in the final discharge area 13 enlarges to bring the level of 6 back down, or again the opposite logic is true. Tap hole 31 also has electric heaters 35′ (which can be any suitable heater such as resistive or induction heaters) imbedded to insure the tap hole stays open or for start-up purposes.

Crucible 21 also has electric heaters 35 to maintain molten conditions either at start-up or in operations. Crucible 21 and the whole upper areas of gasifier 1 would be refractory lined, insulated, and the outer shells water cooled and have an outer layer of insulation, all not shown in detail on the drawing. Also, the lower crucible 21 is shown welded to the upper gasifier area 1 with flange 36 to define a single vessel furnace. They can be easily separated for shut down maintenance by burning off the weld at flange 36. Generally, preferred construction is 100% welded. No bolted flanges are used to prevent gas leakage and lower the cost of construction. Welds are quickly removed to disassemble for shutdown maintenance.

Another advantage of this invention is it enables 100% recycling of slag 13 which is made possible by processes similar to what is used in the cement industry, that is by cooling and clinkering the slag and storing and for later milling into a cementous products where additional amendments and cement can be added to make a products useful in building roads and foundations and the like. A preferred cooling and emissions system is described following.

As can be seen in FIG. 2, slag 13 falls by gravity into gas cooler 37 through opening 38 onto its air-cooled pin-hole grate or equal 39 whereby clinkers 40 are formed from air cooling effects and are kept moving along the grate by an oscillating pusher 41 actuated by motor 42. Blower fan 43 cooperates with ID fan 44 through pressure sensor 45 to insure a balanced air feed and discharge so induced air 46 through the slag inlet is kept to a minimum. Cooled and clinkerized slag 40 passes though crusher 47 and air-lock rotary valve 48 as cooled crushed clinker 49 which is transported away by conveyor 50 shown as an arrowed line to storage to be later milled and mixed to make cementous products as noted above. These cement plant mixing and blending processes are well known and so are not described here.

Temperature sensors to control pressurized air flow 51 and final clinker 49 temperature are not shown but are well known in the art. Hot gases 52 have heat recovered by unit 53, and the gases are cleaned by electrostatic precipitator and scrubber unit 54 before passing through ID fan 44 to stack 55.

While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A blast furnace comprising:

a vessel including a crucible formed therein;

means for introducing fuel and oxygen into said crucible; and

means for determining density characteristics of molten material inside said crucible.

2. The blast furnace of claim 1 wherein said means for determining density characteristics of molten material includes a vertical array of laser spectrometry sensors mounted in said crucible.

3. The blast furnace of claim 1 wherein said means for determining density characteristics of molten material includes an oscillating ball sensor located in said crucible.

4. The blast furnace of claim 1 wherein said means for determining density characteristics of molten material includes an inclined nuclear level gage.

5. The blast furnace of claim 1 further comprising a cyclone positioned adjacent to said vessel for removing particulate matter from hot gas discharged from said vessel.

6. The blast furnace of claim 5 wherein said cyclone includes a leg having an end that is immersed in molten material in said crucible.

7. The blast furnace of claim 6 further comprising means for heating said cyclone and said leg.

8. The blast furnace of claim 7 wherein said means for heating comprises electric heaters.

9. The blast furnace of claim 1 further comprising means for measuring characteristics of hot gas in said vessel.

10. The blast furnace of claim 9 wherein said means for measuring characteristics of hot gas include a laser spectrometry emitter and receiver mounted on said vessel.

11. The blast furnace of claim 1 wherein said crucible includes a tap hole for discharging molten material therefrom.

12. The blast furnace of claim 11 further comprising means for heating said tap hole to insure said tap hole stays open.

13. The blast furnace of claim 12 wherein said means for heating comprises electric heaters.

14. The blast furnace of claim 11 further comprising means for cooling and clinkering molten material discharged from said tap hole.

15. The blast furnace of claim 1 further comprising means for heating said crucible.

16. The blast furnace of claim 15 wherein said means for heating comprises electric heaters.

17. A process comprising:

providing a vessel including a crucible formed therein;

introducing fuel and oxygen into said crucible;

combusting said fuel in said crucible to produce molten material; and

determining density characteristics of molten material inside said crucible.

18. The process of claim 17 further comprising adjusting the input of fuel and/or oxygen into said crucible based on the density characteristics of molten material inside said crucible.

19. The process of claim 18 further comprising using laser spectrometry to measure characteristics of hot gas inside or outside of said vessel.

20. The process of claim 18 further comprising discharging molten material from said crucible and cooling and clinkering molten material discharged from said crucible.