Method for burning solid or semi-solid fuel

Abstract

A mixed low-carbon alcohol ignition agent in a gel paste or a thin cake, and a cylindrical fire-leading coal and a cylindrical coal placed underneath having a high volatile content and honeycomb-like vent holes which are made from solid fuels such as bitumite, lignite, biomass fuels, polyolefin and waste plastics as well as nontoxic excipients, are vertically combined into a coal pile to be combusted in a furnace core, and the number of the pile may be increased. A firing slip of paper is thrown in to ignite the ignition agent from the top, a long-flame combustion is generated soon, and the fire-leading coal catches fire. A high-temperature zone ranging from 400° C. to 800° C. may be rapidly formed in a simple large combustion chamber between the top of the coal pile and the fire-gathering plate. The radiant heat plus the conductive heat is greater than the convective heat, and the red hot coal layer on the surface of the fire-leading coal will gradually move down at a rapid speed, which causes the coal placed underneath to catch fire. The three major components of the coal pile are elaborately formulated and prepared. The material of the furnace core must fit the coal pile. The high-temperature zone is in the upper portion and the low-temperature zone is in the lower portion, which produces an orderly, long-flame, complete combustion and a static combustion without an air blast, thus realizing a combustion with zero smog throughout the whole process starting from the moment of ignition. In addition, the sulfur-fixing rate is high, the cleanliness of the exhaust gas is close to that of natural gas, the exhaust gas may be discharged directly, the heat-generating efficiency is high, the cost is low, the slag is used as a fertilizer, and it is suitable for various small- and micro-sized stoves for heating and warming.

1 - 16 . (canceled) 
     
     
         17 . A zero-smog combustion technology of bitumite, lignite, biomass fuels, and waste plastics such as polyolefin,
 in comparison with a way of combusting a combustible solid substance such as bitumite, lignite and a plant fuel dispersedly and disorderly in existing medium-, small- and micro-sized stoves that leads to a massive amount of many kinds of pollutants such as smog in exhaust emission, the combustion technology is characterized by integrating 6 techniques, i.e., {circumflex over (1)} a gel paste or gel thin cake of low-carbon alcohols is used in combination with a straw charcoal grille as an oxidant-free and nontoxic ignition agent; {circumflex over (2)} in a formula of a fire-leading coal ( 10 ), a total volatile content is up to 30%-40%-50% to facilitate quick energizing after ignition and forming a continuous long-flame combustion; both of an ignition point and a particle size of each component of a combustible substance must be appropriately distributed to facilitate sequential and orderly combustion; after partially emulsified with KOH, a lignite humic acid and a carboxylic acid with a large molecular weight in other raw materials, together with a plant fuel alkalized by an alkaline substance such as KOH and Ca(OH) 2 , constitute a cheap organic binder to facilitate moderately reducing an ash content and increasing a calorific value and a mechanical strength; the raw material is not added with a toxic and harmful substance, there is less slag which is slightly loose to facilitate automatically falling, the slag contains a fertilizer element such as potassium, calcium, magnesium, silicon and sulfur and is slightly alkaline, and when used in combination with a grass fertilizer, it is suitable for improving a granular structure and fertility of an acid clay and may also be used as a cement additive; {circumflex over (3)} both of a top half part of a matched novel furnace core ( 2 ) and a novel fire-gathering plate ( 6 ) are modularly produced from a light-colored material that has both a dominated thermal insulation property and a fire resistant property, so as to facilitate forming a high-temperature zone in a large combustion chamber ( 7 ) soon after ignition, to facilitate horizontally stacking any number of composition units of coal briquettes in various kinds of hearths, and to facilitate promptly assembling the furnace cores in any shape and dimension on site when the hearth is reconstructed; {circumflex over (4)} the cross-sectional area of a primary air inlet of the stove and the vent holes of the coal briquette must be 10%-25%-30% larger than that of an anthracite originally burnt; the cross-sectional area of an inner ring vent hole ( 13 ) of the coal briquette is 30% or more larger than that of an outer ring vent hole ( 12 ) thereof to facilitate ensuring adequate oxygen supply necessary for complete combustion in the case of static combustion without an air blast, an industrial stove should be equipped with a programmed ventilation device to control a flame coming out from the hearth to be in a state of oxidizing flame all the time; {circumflex over (5)} inexpensive nanoscale Fe 2 O 3  is added to a coal surface of the raw material as a catalyst of the coal gasification and water-gas shift reaction of the intramolecular and extramolecular moisture in a fixed carbon and the coal briquette in a micropore in a red hot layer and the vent hole in a red hot portion of the coal briquette which are two kind of self-contained coal gasification chambers that act as combustion chambers as well, so as to facilitate prolonging a long-flame combustion period substantially, and expensive ferrocene may not be used to catalyze the combustion of coal; and {circumflex over (6)} the composition unit of coal briquettes placed in the stove at one time is constituted by a coal placed underneath ( 9 ), the fire-leading coal ( 10 ), an ignition cake ( 9 ), a straw charcoal grille ( 11 ), and the ignition agent layer consisting of an ignition paste in this order from bottom to top, and any number of the composition units may be horizontally stacked; by means of igniting from the top of a coal briquette pile and combusting downward automatically, an orderly, long-flame, complete and zero-smog combustion throughout the whole process from the moment of the ignition of a solid fuel such as bitumite and lignite may be achieved, a sulfur-fixing rate is high, a heat-generating efficiency is high, a cleanliness of an exhaust gas discharged directly is close to that of natural gas, and the exhaust gas may be discharged directly.   
     
     
         18 . The zero-smog combustion technology of  claim 17 , wherein the number of the carbon atoms included in a mixed low-carbon alcohol of the gel of the ignition paste and the ignition cake ( 8 ) is generally 2 to 9, including the cases of using ethanol alone with or without water and using isopropanol alone with or without water (though methanol also has the same igniting effect and may also be included, due to its hypertoxicity, the present disclosure does not advocate methanol being widely used in small and micro-sized stoves); the structural isomerism of a carbon chain is not limited, and the number and the primary or secondary or tertiary attribute of the hydroxyl functional group are not limited; major concern for formulating is that a flash point, an ignition point, a melting point and volatility should have a gradient distribution, therefore, within 2 to 3 minutes after ignition, it is able to produce a sequential combustion, so as to prolong the extremely precious long-flame combustion period of the relatively high-cost ignition agent; a part of the gel melted by heating is concurrently absorbed by the straw charcoal grille ( 11 ) in the upper portion and the micropores of the fire-leading coal ( 10 ) in the lower portion, and a good situation of three-dimensional combustion and long-flame combustion appears soon, which is very favorable for starting combustion smoothly and reliably in a zero-smog state and forming the high-temperature zone in the large combustion chamber ( 7 ). 
     
     
         19 . The zero-smog combustion technology according to  claim 17 , wherein the formula of the ignition cake ( 8 ) is as below: a) isopropanol: 46%, b) ethanol: 20%, c) ethanediol: 5%, d) water: 20%, e) calcium stearate: 5%, f) magnesium stearate: 3%, and g) hydrated lime: 1%; the key points of a production process of the ignition cake ( 8 ) are as below: to an enamel jacketed stirring reactor, weighed and mixed low-carbon alcohols a, b and c are added; while opening the jacket and starting heating with steam, gelatinizing agents e and f are added gradually, and a proper temperature to safely dissolve the gelatinizing agents ranges from 60° C. to 70° C.; after the gelatinizing agents are fully dissolved, a supplementary curing agent g and a burning rate inhibitor and gelling temperature rate regulator d are added; a sample is taken and the gelling temperature is measured, which should be higher than 40° C.; a material temperature is maintained at 50° C. to 60° C., and a feed liquid is poured into a stainless steel die having a diameter of 100 mm and a height of 150 to 300 mm; after the temperature is lowered to 35° C. or less, the material is demoulded and sliced, generally, a thickness of 4 to 5 mm may be adaptable to the most difficult situation where a briquette fuel has a minimum diameter of 100 mm and one composition unit is stacked [the straw charcoal grille ( 11 ) is added additionally for assisting ignition] in the freezing cold season; each single slice is encapsulated with a polyacetate fiber (cellophane) film bag which has the smallest breathability among the common plastic films; each 10 slices are packaged in a polyethylene ultra-thin bag and then packaged in a 5 kg corrugated carton for storage; the highest allowable temperature for storage and transportation is 38° C.; and it should be noted that a feeding pipe and a pipe fitting must be well insulated to prevent condensation and blocking at the time of casting. 
     
     
         20 . The zero-smog combustion technology according to  claim 17 , wherein the formula of the ignition paste is as below: a) isopropanol: 46%, b) ethanol: 20%, c) ethanediol: 5%, d) calcium oleate: 3%, e) magnesium oleate: 1%, f) calcium stearate: 3%, g) magnesium stearate: 1%, and h) water: 21%; the key points of a production process of the ignition paste are as below: in the same reactor as that for producing the ignition cake ( 8 ), weighed and mixed low-carbon alcohols a, b and c as well as gelatinization and paste-forming agents d, e, f and g are added at a low stirring speed, and the temperature is raised slowly up to 60° C.; after the paste-forming agents are fully dissolved, a burning rate inhibitor and gelatinization and paste-forming temperature rate regulator h is added gradually; a sample is taken and the gelatinization temperature is measured, and 46±2° C. is qualified; the mixture is stirred continuously and heating and cooling are alternated; the fluctuation range of the temperature is controlled within 55° C. to 60° C., and the mixture is started to be filled in a polyvinyl chloride collapsible tube, sealed with a screw top, and packaged in a 10 kg corrugated carton for storage; and the highest allowable temperature for storage and transportation is 38° C. 
     
     
         21 . The zero-smog combustion technology according to  claim 17 , wherein the straw charcoal grille ( 11 ) is an attachment specially designed for assisting the ignition, reducing an ignition cost and improving an ignition reliability of the small- and micro-sized stove used in freezing cold weather in winter at high and middle latitudes and in regions with an elevation of 2000 meters or more; after the ignition, the straw charcoal grille ( 11 ) will soon absorb the melted and burning liquid of the ignition paste or the ignition cake ( 8 ) to burn itself red and become a heat insulating layer of the top of the fire-leading coal ( 10 ); the straw charcoal grille ( 11 ) keeps a red hot state of the coal layer at the top of the fire-leading coal ( 10 ) until the long flame regenerates when the long flame of the ignition paste or the ignition cake ( 8 ) is shortened and the ignition paste or the ignition cake ( 8 ) are about to burn out, and cooling and flameout may happen; a formula and the key points of a production process are as below: to a blender mixer, added are 100 kg of a fully carbonized product of straw, pine, China fir, or the like that all pass through a 10-mesh sieve, 2.8 M or more of a potassium water glass binder with a concentration of 15% to 20% in an amount of 6% of the carbonized product based on the dry base, and 3 kg of hydrated lime powder; after uniformly mixed, the mixture is molded into a shape and then naturally dried in a well-ventilated and simple warehouse-like workshop, and is packaged in a super-thin plastic bag and then packaged in a corrugated carton in two stages for release. 
     
     
         22 . The zero-smog combustion technology according to  claim 17 , wherein the fire-leading coal ( 10 ) is an important structural-type coal block necessary for connecting the ignition agent with the coal placed underneath ( 9 ); the fire-leading coal ( 10 ) mainly takes advantage of the following technical principles and technical measures to design a good occurrence state for each component, so as to facilitate maintaining smooth ignition in a zero-smog and long-flame combustion state at the lowest cost and quickly forming the high-temperature zone in the large combustion chamber ( 7 ), which is extremely important for consolidating an orderly, long-flame and sequential combustion and ensuring the red hot coal layer to gradually move downward at a designed speed; to this end, {circumflex over (1)} the formula must be featured in having a high volatile content, and it is suitable that the total volatile content accounts for 30%-40%-50% if a total weight of the volatiles of bitumite and lignite and several other macromolecular organics is counted as the volatile content; {circumflex over (2)} both of the ignition point and the particle size of each fuel component must be properly distributed; {circumflex over (3)} among various fuel components, there must be a proper particle size distribution based on the particle size; {circumflex over (4)} each component itself has a rational particle size distribution, for example, the coke powder all passes through a 80-mesh sieve; bitumite all passes through a 30-mesh sieve, so it naturally includes nanoscale, micron-scale and millimeter-scale particle size distributions; lignite all passes through a 20-mesh sieve, whose particle size distribution is similar to that of bitumite; plastic sheets and particles of waste polyolefin have a particle size of less than 2 mm and also contains small sheets and fine particles; the biomass fuel particles have a particle size of less than 3 mm and carry a large amount of fine power themselves; {circumflex over (5)} after a fuel containing a macromolecular organic acid, such as lignite, is partially saponified with a KOH solution, the biomass fuel particles and hydrated lime are added to be properly boiled to absorb the macromolecular organic acid (partially adsorbed by the pulverized coal) so that the fuel is highly dispersed, which facilitates an orderly combustion at a high temperature and thus effectively avoiding the black smoke produced when a macromolecular organic containing a fused ring is burned, while substantially decreasing the production of 3,4-benzopyrene as a cancerogen; the alkalized biomass fuel particles and a part of the saponified fuels such as lignite together constitute a cheap organic binder for coal briquettes, which is quite beneficial for reducing the ash content, increasing the calorific value of the formula and reducing cost; {circumflex over (6)} the plant fuel particles are combusted firstly and other volatiles and nanoscale carbon are combusted successively, such that there have been a considerable number of micropores as micro-coal gasification reaction chambers (selecting the pigment ferric oxide in which the nanoscale particles account for 10% or more as a catalyst to replace the expensive ferrocene) and combustion chambers of the fixed carbon in the red hot coal layer; a considerable portion of the fixed carbon is gasified, which facilitates prolonging the long-flame combustion period; the fuel gas keeps burning when passing through the vent holes ( 12 ,  13 ) of the red hot coal layer which act as such small combustion chambers and gasification chambers, thereafter, the fuel gas is substantially combusted completely through the large combustion chamber ( 7 ), and finally undergoes after combustion in a main torch with a secondary air intake; the four-stage continuous combustion is another guarantee condition for realizing complete combustion; {circumflex over (7)} the number of equivalents of hydrated lime compounded as a sulfur-fixing agent is 3 to 5 times that of the total sulfur content of the fuels, and potassium is added additionally to guarantee a high sulfur-fixing rate, since a portion of calcium will be consumed to bind to silicate instead of fixing sulfur; {circumflex over (8)} a toxic and harmful raw material in which the radioactive element(s) exceeds the standard and lead, cadmium, arsenic, mercury, beryllium, thallium, halogen, or the like is contained is rejected, there is less slag in an amount of 10% to 12% in general, and the slag has a loose structure and may almost fall automatically; these factors are very important for a continuously-operating industrial stove; the slag contains the fertilizer elements such as potassium, calcium, magnesium, iron, silicon and sulfur; the slag is slight alkaline after naturally absorbing oxygen and carbon dioxide for several days without being exposed to the rain, and is suitable as a fertilizer and granular structure improver for acid clay after used in combination with an organic fertilizer, or the slag may be used as a cement additive; a formula, the key points of a production process and a packaging of a product for heating are as below: a cylindrical fire-leading coal ( 10 ) having a small diameter of 100 mm is taken as an example, the weight of the ingredient is 200 g for each ingredient on dry base, and a heat of (5000-5300)×4.1868 kJ/kg is suitable; the fire-leading coal is divided into upper and lower layers, fed twice, and hydroformed once; the formula is as below: a) pine sawdust: 20 kg (15 kg), b) peanut shell powder: 5 kg (9 kg), c) fallen rosin: 9 kg (4.5 kg), d) lost-wax casted waste wax (containing stearic acid): 9 kg (4.5 kg), e) potassium hydroxide: 3.2 kg (1.6 kg), f) bitumite: 6000×4.1868 kJ/kg, volatiles: 35%, 18 kg of bitumite which all passes through a 60-mesh sieve, 30 kg of bitumite which all passes through a 25-mesh sieve (the grade of which is identical to the former one, 65.85 kg of bitumite which all passes through a 25-mesh sieve), g) hydrated lime powder: 3.5 kg (5 kg), j. ferric oxide pigment: 0.3 kg (0.35 kg), h) 40% potassium water glass: 5 kg (8 kg), i) water: 40 kg (35 kg); the data in the parentheses is the data of the formula of a lower-layer material of the fire-leading coal ( 10 ); the key points of the production process are as below: into an open iron pan with a paddle stirrer, i, h, c and d are added and heated till boiling; debris such as branches, leaves and stones are picked out; a saponification solution is added to a kneading pot added with a and b while filtering; after kneading under thermal insulation for 15 to 20 minutes, f and h to which j and g have already been mixed are added and the kneading is continued for 10 minutes, and then the mixture is conveyed to the 1# hopper of a hydraulic molding machine; this is an upper feedstock of the fire-leading coal ( 10 ); another set of the same system is used to prepare a lower feedstock of the fire-leading coal ( 10 ), which is conveyed to the 2# hopper of the hydraulic molding machine; the hydraulic molding machine is started and 1# feedstock and 2# feedstock in equivalent amount are conveyed into a molding cylinder in turn while they are hot, compression molded at one time, and transferred to a big large-scale low-temperature ventilation drying room while they are hot; the fire-leading coal ( 10 ) is dried at 60° C. until the moisture content is less than 10%, and is moved out together with a rail car to a natural cooling section in the workshop; when the temperature is lowered to 35° C. or less, each fire-leading coal ( 10 ) is packaged in an ultra-thin polyethylene plastic bag and then packaged in a corrugated carton for storage; a molding pressure is carefully adjusted according to the variety and specification of the product and subjects to a standard that the mechanical strength of the product is able to adapt to a logistic operation in a non-barbaric state and the product is not easy to break, so as to maintain a proper crispness, which facilitates a rapid temperature rise and the coal gasification reaction of the fixed carbon in an ignition stage. 
     
     
         23 . The zero-smog combustion technology according to  claim 17 , wherein the high-temperature zone above the coal placed underneath ( 9 ) has been already formed, and is easy to be smoothly ignited; the flexibility of the formula is large, but it is still necessary to pay attention to a reasonable occurrence state of the components and a gradient principle to guarantee a good state of a sequential combustion; the focus of some formulas has turned to the use of low-cost raw materials and a product is supplied to the scattered residents in villages at a lower unit price and used for heating; a formula and the key points of a production process of a product for heating are as below: calorific value: 4000×4.1868 kJ/kg, volatiles: 40%, a) straw pieces: 10%, b) pine sawdust: 10%, c) 20% of potassium water glass: 8%, d) bitumite powder (5500×4.1868 kJ/kg, volatiles: 30%, sulfur: 2.5% or less): 68%, e) hydrated lime powder (in term of equivalent): 3 times of sulfur equivalent, f) ferric oxide pigment: 0.5%, g) plastic pieces of polyolefin waste: 5%, and i) water: 5%; d with a fineness of 25 mesh and the moderately-sized a, b and g are weighed, put into a mixer, and mixed for about 10 minutes; thereafter, the pre-mixed e and f that are 10 times of the weight of d, a and b are added and the mixture is mixed continuously for several minutes; a binder c is sprayed and the mixture is mixed for another several minutes; the mixture is moved into a hopper of a hydraulic molding machine, molded with a large pressure, stored and dried naturally; when entering the stove, containing 10% to 15% of moisture is quite advantageous to the coal gasification reaction of the fixed carbon. 
     
     
         24 . The zero-smog combustion technology according to  claim 17 , wherein the coal briquette fuel, the vent hole, a hole diameter and an arrangement are rational; regardless of whether the coal briquettes are made into a cylindrical or square column and regardless of their geometric sizes, all the coal briquettes adopt circular and straight vent holes, and a total cross-sectional area of the vent holes is 10%-20%-30% larger than that of a commercially available anthracite (which is called honeycomb briquette in the south), so as to adapt to the requirements for large oxygen consumption necessary for fast combustion of the volatiles with a high content in the solid fuel; the diameters of several vent holes ( 13 ) in a central part of the briquette need to be extraordinarily enlarged so that they are 2 to 3 mm larger than those of the peripheral vent hole ( 12 ), to enable the big torch flame beam from a primary hole in the center of the fire-gathering plate ( 6 ) to further get fresh air in an amount similar to that obtained through a peripheral secondary air inlet hole ( 4 ) in the furnace core ( 2 ); when a plurality of composition units are horizontally stacked in a large hearth, the distance between the composition units in the central part is 2 to 3 mm larger than that between peripheral units for the same purpose of getting adequate amount of fresh air; the area of a primary air inlet and soot door ( 5 ) at the lower portion of the stove should be suitably 5% to 20% larger than a sum of the total area of the vent holes of the briquettes and the total area of gaps around the briquettes; the more the composition units are, the closer the value is to 20%; making the above three improvements which increase the oxygen supply is quite essential, in this way, complete combustion may be guaranteed without providing an air blast or heightening a chimney. 
     
     
         25 . The zero-smog combustion technology according to  claim 17 , wherein a space is present with sufficient size (whose volume is not less than that of one piece of coal placed underneath ( 9 )) above the furnace core ( 2 ), and the furnace core ( 2 ) is covered with the fire-gathering plate ( 6 ) to form a simple large combustion chamber ( 7 ); in case that a formula has an extremely high volatile content and a coal gasification rate of the fixed carbon is also high, the height of the large combustion chamber ( 7 ) needs to be properly increased; the height of the combustion chamber plus the height of the furnace core ( 2 ) corresponding to the height of the fire-leading coal ( 10 ), should be made from an material that has both a dominated thermal insulation property and a fire resistant property, is alkaline on the whole, and has a high content of magnesium and a low content of transition element(s); a material of the furnace core of a conventional stove is selected only by considering the fire resistance, which is quite unfavorable for a crucial design of a smooth ignition in a zero-smog state in a small-sized heating stove in freezing cold weather in winter and an early formation of the high-temperature zone in the large combustion chamber ( 7 ); coal briquettes formulated according to a sulfur-fixing formula are strong alkaline and are liable to be welded to an acidic furnace core at a high temperature; the low content of the transition element(s) (coloring element(s)) is able to make the furnace core ( 2 ) light-colored and good for light and heat reflection, which is advantageous for rapid temperature rise after ignition; it is preferred that the fire-gathering plate ( 6 ) has a thin thickness and a light weight; preferably, the material is the same as the thermal insulation-fire resistance material for the upper portion of the furnace core ( 2 ), and more preferably and most preferably, the color of the fire-gathering plate ( 6 ) is nearly white; the periphery of the fire-gathering plate ( 6 ) is preferably embedded with a circle of stainless steel strip or cheap steel strip with good sulfur resistance to reinforce it; in short, the fire-gathering plate ( 6 ) is better when it absorbs less heat and its inner arc-shaped surface reflects more light and heat downwards; as for industrial and cooking stoves requiring great heat power and high operating temperature, and stoves used for coal briquettes having the minimum diameter (often 100 mm), single composition unit and ignition in a freezing cold season, the fire-leading coal ( 10 ) having a high calorific value and capable of fast burning which is used in combination with the furnace core ( 2 ) and the fire-gathering plate ( 6 ) having such high performance is required; as for stoves for heating, baking, drying, and boiling hot water in a region with lower latitude, the low-cost fire-leading coal ( 10 ) may be chosen to be used in combination with the furnace core ( 2 ) and the fire-gathering plate ( 6 ); a stacking manner of the coal briquettes of the present disclosure is as follows; each combustion unit which is placed in the hearth ( 2 ) for combustion comprises one straw charcoal grille ( 11 ) and one ignition cake ( 8 ), one piece of fire-leading coal ( 10 ), and one to three pieces of coal placed underneath ( 9 ) in turn from top to down; if the ignition paste is used, the ignition paste is temporarily squeezed on the top of the fire-leading coal ( 10 ) before ignition and then ignited immediately after the coal placed underneath ( 9 ) and the fire-leading coal ( 10 ) are placed inside; a plurality of composition units may be horizontally stacked arbitrarily and ignited as necessary, and this naturally needs to fit the hearth, the furnace core ( 2 ), the fire grate ( 15 ) and the fire-gathering plate ( 6 ); when a plurality of composition units are employed in a large hearth, since “many hands make light work”, a using amount of the ignition agent is less, i.e., the cost may be reduced appropriately, the temperature rises rapidly, and the beneficial effect is remarkable. 
     
     
         26 . The formulas and production processes exemplified in the specific embodiments are merely for further illustrating the content of the present disclosure, but are not limited thereto, and the embodiments are all included in the scope of the present disclosure as long as they adopt the following technical contents in the briquette fuels for “upper ignition-downward combustion”: 1. a gel paste or cake ( 8 ) of low-carbon alcohols is used as an ignition agent, and a straw charcoal and other plant charcoals are used as auxiliary ignition agents, regardless of how a formula, a production process and a packaging form are adjusted; 2. a formula and a molding process of a fire-leading coal ( 10 ), as long as a) an ingredient having a high volatile content of 30%-40%-50% is adopted, b) both of the ignition point and particle size of each fuel component are arranged in gradient to facilitate an orderly and sequential combustion, and c) after lignite and other materials containing a macromolecular organic acid are partially emulsified (neutralization reaction with potassium hydroxide and the like), the mixture and a plant fuel boiled with an alkaline substance such as potassium hydroxide, hydrated lime and plant ash together constitute a fuel and binder, so as to save the cost of the binder, regardless of how the formula, the production process and the packaging form are adjusted; 3. commercial iron sesquioxide containing at least 10% or more of iron sesquioxide and having a particle size of 50 nm or less is adopted to catalyze a part of a fixed carbon in a coal component to be gasified in a micropore and a vent hole in a red hot coal layer before combustion, so as to facilitate the extension of a long-flame combustion period; 4. a furnace core ( 2 ) has a height of at least from the bottom of the fire-leading coal ( 10 ) to the bottom of a fire-gathering plate ( 6 ), and the fire-gathering plate ( 6 ) itself is made from a light alkaline fire-resistant material having good thermal insulation property and containing a high content of magnesium and a low content of transition element(s); 5. a total area of an air inlet of a stove and the vent holes of the coal briquettes is enlarged by 10-20-30%, as compared to that of an anthracite originally used, and the diameter of an inner ring vent hole ( 13 ) is 10% to 11% larger than that of an outer ring vent hole ( 12 ); 6. after tests, a raw material does not contain radioactive elements beyond standard, does not contain lead, cadmium, arsenic, mercury, thallium, and beryllium, and does not contain halogen, much sulfur and nitrogen and other toxic and harmful substances, so the burnt slag mainly contains elements such as potassium, calcium, magnesium, iron, silicon and sulfur, thus being used as a fertilizer or a cement additive; and 7. various combustible solids and semi-solids, including a low-value waste thereof, may all be used as a formulated fuel according to the methods described in the present specification to realize highly efficient and clean combustion, and are thus included in the content of the present disclosure.