Coal Gasification Products Research Articles

Coal Seam Gasification in Faulting Zones (Heat and Mass Balance Study)

In this article, the mass and heat balance calculations of underground coal gasification process for thin coal seams in faulting zones of Lvivskyi coal basin (Ukraine) are defined. The purpose of the research is to establish regularities of heat and mass balance changes in faulting zones influence due to usage air and oxygen-enriched blast. A comprehensive methodology that included analytical calculations is implemented in the work. The output parameters of coal gasification products for the Lvivvyhillia coal mines are detailed. The heat balance is performed on the basis of the mass balance of underground coal gasification analytical results and is described in detail. Interpretations based on the conducted research and investigation are also presented. Conclusions regarding the implementation of the offered method are made on the basis of undertaken investigations. According to conducted research the technology of underground coal gasification can be carry out in the faulting zone of stable geodynamic and tectonic activity. The obtained results with sufficient accuracy in practical application will allow consume coal reserves in the faulting zones using environmentally friendly conversion technology to obtain power and chemical generator gas, chemicals and heat.

INCREASE OF COMBUSTION EFFICIENCY OF ORGANIC FUELS IN COMBINED STEAM AND GAS POWER PLANTS

Ukraine's thermal energy is in critical condition due to the wear of technological equipment and huge emissions of harmful substances to the atmosphere, while the combined power system of the state is characterized by a significant shortage of maneuver capacity. Combustion of organic fuel in existing boiler units, manufactured in the middle of the last century, is inefficient due to the formation of nitrogen oxides. The reaction of their formation is endothermic, which leads to decrease of flue gas temperature, causing decrease of efficiency of the entire power unit. In order to correct the existing situation, it is proposed in this article while retrofitting existing TPPs, which will have to be implemented, use combined steam and gas power plants, where traditional steam method of electricity generation is combined with gas generation. It is shown that the gas unit of the power plant can work on low-quality coal gasification products. It is expedient to carry out gasification in the additional furnace, where a part of the powdered coal is supplied, the additional furnace itself consists of two-walls and compressed air enters the space between the walls for heating and formation of the gas turbine working environment. At this stage, the excess air ratio is slightly less than the stoichiometric amount required for complete combustion. In order to increase the efficiency of combustion in the main and additional furnaces oxygen enriched air is used. To enrich the air with oxygen, it is reasonable to use membrane technologies that provide two to three times higher oxygen content compared to currently used combustion technologies. As far as oxygen-enriched fraction is used in the combustion process, it reduces the amount of so-called atmospheric nitrogen oxides. The nitrogen fraction is utilized in the gas cycle of electricity generation. Such a combined steam and gas power plant has a much larger range of power variations, that is, it is more maneuverable, the speed of power ascension increases – it becomes more mobile, and due to the use of membrane air separation technologies, the amount of formed nitrogen oxides is reduced. The temperature of the flue gases increases which improves the efficiency factor, as well as the amount of flue gases at the flue outlet is reduced.

Optical spectra of coal gasification products in the RF plasmatron

The use of solid fuel gasification process is relevant to the regions where there is no opportunity to use natural gas as the main fuel. On the territory of the Russian Federation such regions are largely the Urals, Siberia and the Far East. In order to reduce the harmful effects on the environment solid fuel with high sulfur content, ash content and moisture are subjected to gasification process. One of the major problems of this process is to produce syngas with a low calorific value. For conventional types of gasification (gasification), the value of this quantity ranges 8 - 10 MJ / m3. The use of plasma gasification increases the calorific value of 12 - 16 MJ / m3 which allows the most efficient use of the syngas. The reason for the increase of the value lies in the change of temperature in the reaction zone. A significant rise in temperature in the reaction zone leads to an increase in methane formation reactions constant value, which allows to obtain a final product with a large calorific value. The HFI-plasma torch coal temperature reaches 3000 ° C, and the temperature of coal gasification products can reach 8000 ° C. The aim is to develop methods for determining the composition of the plasma gasification products obtained optical spectra. The Kuznetsky coal used as the starting material. Received and decrypted gasification products optical spectra in a wavelength range from 220 to 1000 nm. Recommendations for the use of the developed method for determining the composition of the plasma gasification products. An analysis of the advantages of using plasma gasification as compared with conventional gasification and coal combustion.

Cement bonded fine hematite and copper ore particles as oxygen carrier in chemical looping combustion

In this work, bimetallic oxygen carriers (OCs) were prepared from waste fine particles (<0.1mm) of natural copper ore and hematite for possible application in chemical looping combustion (CLC) processes. The mixtures with different mass ratios of copper ore to hematite were physically bonded by 20wt% of calcium aluminate cement to obtain OC particles with relatively high disperse structure and good mechanical strength. Cyclic isothermal redox tests were first conducted in a thermogravimetric analyzer (TGA) to optimize the copper ore to hematite mixing ratio in the bimetallic OC. Synergistic effect between copper ore and hematite was observed, and the copper ore to hematite mixing ratio was optimized at 20:80 (namely Cu20Fe80@C) based on a comprehensive consideration of OC reactivity, economic cost and auto-thermal balance in fuel reactor. Subsequently, performance of Cu20Fe80@C and Fe100@C (cement bonded pure hematite) were further evaluated in a batch fluidized bed reactor, using coal as fuel. The Cu20Fe80@C was found to be more reactive towards coal gasification products than that of Fe100@C, which is mainly attributed to the synergistic effect attained by the coexistence of copper ore and hematite in the Cu20Fe80@C OC. Moreover, the effects of steam concentration, oxygen to fuel ratio and coal type on the performance of Cu20Fe80@C were investigated. It was found that both the increase of steam concentration and oxygen to fuel ratio can facilitate the coal conversion, but they are not the higher the better and should be balanced between coal conversion and operational cost when turning to industrial application. Lignite was more suitable to be converted by Cu20Fe80@C OC in iG-CLC process due to its better gasification reactivity than anthracite. 30 cyclic redox tests with lignite showed that Cu20Fe80@C exhibited superior redox reactivity, nice fluidization behavior and good anti-sintering property in fluidized bed tests. This work demonstrated that cement bonded fine particles of hematite and copper ore could be a promising and competitive OC candidate for industrial application in iG-CLC processes.

Performance of iron ore oxygen carrier modified by biomass ashes in coal‐fueled chemical looping combustion

AbstractThe modification of oxygen carrier by low‐cost biomass ash shows great potential to reduce the economic and environmental costs associated with oxygen carrier preparation and biomass ash disposal. In this study, three biomass ashes ‒ a wheat stalk ash (WSA), a corn stalk ash (CSA), and a soybean stalk ash (SSA) ‒ were selected as the modifiers to evaluate their potential to improve the reactivity of a iron ore produced from the Mining Area C (MAC) of Western Australia. A lignite coal ash‐modified MAC iron ore was also prepared to make a comparison. The reactivity performance of ash‐modified samples and the cyclic behavior of the selected best candidate were evaluated in a laboratory‐scale fluidized‐bed reactor system with coal as fuel. The results showed that MAC iron ore loaded with different ashes showed different degrees of improvement in its reactivity. SSA‐modified MAC iron ore behaved the best due to the highest K2O content and the total contents of K2O, CaO, and Na2O in SSA as well as its great resistance to melting. The higher loading content of SSA in MAC iron ore resulted in more coal gasification products converted to CO2 and H2O at a faster reaction rate. The cyclic test of MAC‐20SSA showed that it performed well both in its reactivity and physical structure. Stable outlet gas concentrations were achieved and MAC‐20SSA exhibited good resistance to sintering. It can be inferred that SSA is a promising low‐cost modifying agent to enhance the performance of oxygen carrier while reducing the environmental impact associated with its disposal. © 2016 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Best available techniques assessment for coal gasification to promote cleaner production based on the ELECTRE-II method

Coal-To-Methanol is a key component in the coal chemical industry and methanol production, as well as large source of pollutants, mainly Chemical Oxygen Demand and Sulphur Dioxide. As a general technique and basis of follow-up processes in the coal chemical industry, selection and assessment of coal gasification techniques plays a crucial role in pollution control and cleaner production. This study explores the best available techniques for cleaner coal gasification production based on the ELECTRE-II method—a widely-used outranking method for multi-criteria decision making. Taking technical features, applicability, environmental and economic benefits into consideration, Gaskombinat Schwarze Pumpe, Shell, opposed multiple burner, Texaco, and atmospheric gasification were selected as the best available techniques from 10 coal gasification techniques. Based on these results, newly-built large-scale Coal-To-Methanol enterprises should select Gaskombinat Schwarze Pumpe. Medium-scale and non-recurring investment limited enterprises should adopt opposed multiple burner or Texaco. Shell is recommended for use in urban gas and thermal power plants. For former small-scale fixed-bed Coal-To-Methanol (or polygeneration) enterprises, atmospheric gasification is recommended to transform conditional fixed-bed gasification technologies. We conclude that the ELECTRE-II method is suitable for assessing coal gasification techniques and identify mature, environmental-friendly, and well-adaptable coal techniques with low construction investment, low running costs, intensive capacity of single-furnace gasification and high automation as best available techniques. This study provides a scientific reference for enterprise managers to choose appropriate coal-to-methanol techniques. Moreover, the introduced index system and the detailed procedure for selecting best available techniques serve as a basis for policy-making about the best available techniques in the coal chemical industry and other industries.

Life cycle assessment of heat production from underground coal gasification

In Poland, coal is the main fuel used for heat production. Innovative clean coal technologies, which include underground coal gasification (UCG), are widely developed. This paper presents the analysis results of life cycle assessment (LCA) and material flow analysis (MFA) of using synthesis gas from UCG for heat production. The paper presents the results of a comparative analysis of MFA and LCA for four variants of heat production, which differed in the choice of gasifying agent and heat production installations. Environmental analysis was made based on LCA with ReCiPe Midpoint and ReCiPe Endpoint H/A method, which allowed to analyse of different categories of the environmental impact. LCA was performed based on the ISO 14040 standard using SimaPro 8.0 software with Ecoinvent 3.1 database (Ecoinvent 2014). Umberto NXT Universal software was used to develop MFA for heat production. LCA analyses included hard coal from a Polish mine and synthesis gas obtained in the experimental installations in the Central Mining Institute in Poland. MFA performed for technology of utilizing gases from UCG have made it possible to visualize materials and energy flow between different unit processes in the whole technological chain. Moreover, the analyses enabled identification of unit processes with the largest consumption of raw materials, energy and the biggest emissions into the environment. It has been shown that the lowest environmental burden is attributed to the technology, which uses high-pressure chamber with gas turbine in which the synthesis gas from UCG is burned and oxygen was a gasifying agent. Analysis of LCA results showed that the major environmental burden includes greenhouse gas (GHG) emission and the fossil fuels depletion. GHG emission results primarily from the direct emission of CO2 from gas combustion for heat production and electricity consumption used in gasifying agents preparation phase. In order to increase the environmental efficiency of heat production technology using UCG, the most important activity to be considered is limitation of dust-gas emissions, including primarily CO2 removal process and efficiency increase of the installation, which is reflected in the reduction of coal consumption. It is important to highlight that this is the first attempt of MFA and LCA of heat production from UCG gas. Since no LCA has ever been conducted on the heat production from underground coal gasification, this study is the first work about LCA of the heat production from UCG technology. This is the first approach which contains a whole chain of unconventional heat production including preparation stages of gasifying agents, underground coal gasification, gas purification and heat production.

Forming the Composition of Underground Coal Gasification Products in the Simulation of Various Heat and Mass Transfer Conditions in the Coal Seam

The mathematical model describing the heat and mass transfer processes in underground coal gasification is proposed. Numerical studies have allowed to determine the composition of gases depending on the temperature, pressure products of gasification, and the composition of the heated oxidant injected. Relations the composition of the concentration of combustible gas component of the oxidant injected: dry air, a mixture of oxygen, nitrogen and water vapor in different proportions were prepared. It is found that, depending on the oxygen content in the oxidizer low- temperature gasification mode is implemented (up to 15%). At higher values of the oxygen concentration in the oxidizer the high-temperature mode is realized, in which the fuel gas output increases significantly.

Proposal of a new soot quantification method and investigation of soot formation behavior in coal gasification

Coal gasification is one of the key technologies for utilization of coal. Coal gasification mainly consists of coal pyrolysis, char gasification, and gas-phase reactions. Soot is made up of fine solid carbon particles formed by volatile matter decomposition and has lower gasification reactivity than char. Since the solid products of coal gasification contain both char and soot, it is difficult to quantify the amount of soot produced by this process. In this study, a novel soot and char quantification method utilizing a laser diffraction particle size analyzer is proposed. Coal gasification experiments were performed using a pressurized drop tube furnace (PDTF). The soot and char yields were quantified by the new method. During CO2 gasification, char was selectively gasified and the amount of soot barely decreased. Hence, the carbon conversion initially increased, but remained around 0.8 even at 1673K. In the case of other gasifying agents, O2 or H2O, different behavior was found. During O2 gasification, the soot yield considerably decreased as the O2 concentration increased. The main reason was not soot gasification, as presumed, but rather the reaction of tar components with O2. In the H2O gasification, the soot yield slightly decreased as the H2O concentration increased.

Sulfur inhibition of PdCu membranes in the presence of external mass flow resistance

Coal gasification products typically contain less than 40% H2 and less than 40ppm H2S after desulfurization with ZnO beds at operation temperatures around 773K. Hence, both sulfur poisoning and external mass flow resistance must play a major role in separation of such mixtures with Pd-type membranes. We have investigated the separation of 1:1 and 9:1 H2/N2 mixtures contaminated with 7–35ppm H2S to elucidate the relative importance of these transport resistances using a ca. 5µm thick PdCu membrane supported on a ceramic substrate. Sulfur inhibition depended strongly on H2 recovery (10–80%) and temperature (673–773K) in the investigated range. Sulfur poisoning of the membrane dominated H2 permeation rates at lower temperatures and in the 9:1 H2/N2 mixture especially. However, its impact declined rapidly with increasing H2 recovery in the 1:1 H2/N2 mixture. As a consequence H2 recovery was only slightly reduced from 75% to 70% at 773K even after adding 35ppm H2S to that mixture. This demonstrates that concentration polarization is a stronger limitation to H2 permeation than sulfur inhibition in practical separation situations where very high H2 recovery will be an economic necessity. Exposure to H2S for altogether 75h had no lasting effect on H2 permeability of the membrane but the N2 leak rate doubled presumably due to sulfide formation at defect sites at lower temperatures.

Scanned-wavelength-modulation-spectroscopy sensor for CO, CO2, CH4 and H2O in a high-pressure engineering-scale transport-reactor coal gasifier

In-situ laser-absorption measurements of CO, CO2, CH4 and H2O were demonstrated in the synthesis gas products of coal gasification (here called syngas) from an engineering-scale transport reactor. A wavelength-scanned, wavelength-modulation spectroscopy scheme was used to counter environmental challenges including severe loss in transmitted light intensity due to particulate scattering and beam steering in the synthesis gas stream. Separate lasers were used for each species (CO near 2326nm, CO2 near 2017nm, CH4 near 2290nm, and H2O near 1352nm) and a novel fiber bundle was utilized to combine all four beams on a common optical path. Line-of-sight laser absorption utilized sapphire windows in the synthesis gas product pipe downstream of the gasifier reactor by approximately 5s flow time. Time multiplexing enabled low-noise measurement of the transmitted light with a single detector. Successful measurements of the four species mole fractions were performed throughout the 54day measurement campaign, including a significant period of unattended operation. The mole fractions of the four target species were monitored versus time as the gasifier was transitioned from a cold startup to stabilization at the target 15atm and 1260K gasification condition, and after 35days at relatively steady operating conditions, the campaign was terminated and the reactor shut down. The variations of time-resolved mole fractions of the four species were captured during the heating of the reactor with a propane/air flame, the continued combustion heating of the reactor as coal was added to the fuel, and the transition from combustion to gasification. The average values of CO, CO2 and CH4 measured by the laser absorption sensor were in good agreement with extractive gas chromatography; however, the extractive gas analysis was delayed by ∼20min and had a ∼15min time response due to the transport and conditioning (filtering and drying) of the sampled gas. The laser absorption sensor provided essentially simultaneous species mole fractions with sub-second time resolution, which enabled identification of a wide range of dynamic behaviors. For example, small changes in the reactor conditions due to batch feeding of coal were observed by composition changes in the synthesis gas and were correlated with small temperature fluctuations in the reactor.

Theoretical Research of Coal Gasification Products Burning in Boilers at Tomsk Thermal Power Plant-3

Mathematical modeling of primary fuel change into power gas in power generating boiler with productivity of steam 160 t\h was done. Research of aggregate work on some power modes was completed. Characteristic curves of efficiency coefficient at different loads and ratio on power and natural gases burning were made. Practicability of power gas use as fuel was proved.

Comparative study between fluidized-bed and fixed-bed operation modes in pressurized chemical looping combustion of coal

The performance differences between the fluidized-bed and the fixed-bed operation modes were comparatively studied in a pressurized coal-fuelled chemical looping combustion (CLC) process. Pressurized thermogravimetric (TG) analysis was applied to elucidate the findings observed in pressurized fluidized-bed and fixed-bed experiments. The results showed that the performance of the reaction between coal and oxygen carrier was strongly dependent on the operating pressure and the employed operation mode. Elevated pressure lower than 0.5MPa promoted the conversion of coal gasification products to CO2 and H2O but pressure beyond 0.5MPa resulted in a negative effect for both operation modes. TG and characterization analyses confirmed that the negative effect of pressure had little to do with oxygen carrier property but was mainly ascribed to the suppression of coal pyrolysis at high pressure which leads to a decrease in char reactivity. Fixed-bed mode showed superiority over fluidized-bed mode in enhancing the CO2 concentration and the carbon conversion, but was unfavourable for the pore structural properties of oxygen carrier, and thereby undesirable for long-term stable operation.

Determination and Comparison of CuO Reduction/Oxidation Kinetics in CLC Experiments with CO/Air by the Shrinking Core Model and Its Characterization

The Shrinking Core Model (SCM) has been applied to determine and experimentally validate the reduction and reoxidation (redox) reaction kinetics of CuO in an in situ chemical looping combustion (CLC) process. This paper focuses on the determination of redox kinetics of CuO with one of the major coal gasification products i.e. carbon monoxide (CO) and air in a CLC process using a thermogravimetric analyzer (TGA). The comparison of the kinetic parameters of CuO obtained in CLC experiments, using CO and air as reducing and oxidizing atmosphere, respectively, with the predictions by the SCM model are also presented in this paper. The CuO particles are characterized in detail to obtain structural and elemental changes, due to their cyclic use in CLC experiments with CO/air, compared to the fresh particles. It has been observed that the reduction reaction control mechanism of SCM predicts very well the conversions of CuO during reduction in CO. However, the reoxidation of reduced CuO particles are governed by p...

Reference set selection with generalized orthogonal Procrustes analysis for multivariate statistical process monitoring of multiple production processes

Multivariate process monitoring is important in industry to ensure that production processes perform as close as possible to optimal operation. However, the selection of a reference set of optimal or expected performance is required for efficient process monitoring in real time. In this paper we present the method of generalized orthogonal Procrustes analysis to select a reference set for the multivariate monitoring of multiple production processes simultaneously. We combine generalized orthogonal Procrustes analysis with principal component analysis (PCA) and biplots to illustrate the implementation of the method and the interpretation of the results which provide important information on the relationships between many process variables and differences between the production processes. The work is motivated by an industrial problem involving the multivariate monitoring of a coal gasification production facility considering many process variables monitored across multiple reactors.

Selection of Coal Gasification Parameters for Injection of Gasification Products Into a Blast Furnace

An analytical study was performed on the influence of blast parameters on the course of the processes in the volume of a blast furnace and smelting rates by injection of low-grade coal gasification products. It was found that the use of hot reducing gases produced by an atmospheric blast with the highest possible temperature is more effective for injection into the blast furnace.

Substitution of Coke and Energy Saving In Blast Furnaces. Part 5. Problems and Prospects of Low-Coke Blast-Furnace Technology

Two most promising known non-traditional blast furnace technologies can be used to minimize the coke rate: 1) the tuyere injection of the hot reducing gases with removal of CO2 from the top gas and 100% oxygen blast; 2) injection of 300-400 kg pulverized coal/thm (PCI-technology). The injection of hot reducing gases (HRG) is limited by the heat balance of the entire Iron & Steel Works since the blast furnace gas will not be supplied to other works in sufficient quantity. The combustion and gasification of significant amount of coal and liquation of coal ash in the tuyere’s raceway are the limitations for the PCI-technology. Lack of resources, low-ash coal for pulverized coal injection—PCI (pulverized coal full—PCF) requires solutions to technical problems of the use of high-ash coals, in particular, partial and full gasification of fuel before entering the tuyere area of BF. Injection of the products of coal gasification (PCG) instead of PCI into the blast furnace tuyeres eliminates these limitations. The advantages of this technology in comparison with traditional PCI injection are as follows: increase in coal rate and decrease in coke consumption; possibility of low grade coals usage; elimination of fine coal grinding; gas desulphurization in the course of coal gasification and the possibility of coal ash fluxing and being removed from the process. The special compact coal gasifiers attached to the blast furnaces tuyeres were developed and tested at industrial scale. The estimated decrease in coke consumption from 565 kg/thm to 305 kg/thm with injection of 300 kg/thm of coal gasification products and 105 kg/thm of oxygen was specified with respect to operation of blast furnaces at Zaporozgstal Iron & Steel Works (90 years of the last century). The study by using a multi-zone mathematical model showed that the temperature-concentration and phase fields of the charge and the gas flow in the furnace change under the influence of the same tendencies that are seen with the injection of pulverized-coal fuel (PCF). The fact that the amount of coal which can be injected could be increased significantly by subjecting it to preliminary gasification and fluidizing the ash in tuyere-mounted gasifiers means that the targeted savings of coke could be realized by replacing coke with either high-grade coals (in the form of PCF) or low-grade coals (in the form of CGPs). In this case, for the best variants of the technology the ratio of the equivalents for the replacement of coke by coal is close to the ratio of the contents of nonvolatile carbon in the high- and low-grade coals (0.65 in the present case). The application of the developed technology for blast furnaces with burden composition of BF-5 “Severstal” and BF-9 AMKR will allow further decrease in coke rate to the minimal level of 180-200 kg/thm. The payback period of capital investments for this technology is estimated in the range of one year.

Thermodynamic assessment of an integrated solar power tower and coal gasification system for multi-generation purposes

Multi-generation energy production systems allow higher efficiency by integration of different systems for recovering the highest possible exergy of the energy input. This paper concerns the thermodynamic assessment of a solar-based multi-generation system with coal gasification, involving power, heating, cooling, hydrogen, oxygen and hot water production. The coal gasification system is integrated with a solar power tower to utilize the concentrating solar energy. The clean syngas produced from the system is stored for the continuous power production. This multi-generation system has divided to the six sub-systems. Energy and exergy efficiencies of each system are studied to show the system performance under the chosen conditions and also how to approach the ideal case. From the results, energy and exergy efficiencies of the sub-systems change between 19.43–46.05% and 14.41–46.14%, respectively, and the multi-generation system has the maximum energy and exergy efficiencies as 54.04% and 57.72%, respectively. Additionally, parametric studies, including the thermodynamic performance of the multi-generation system components, are conducted by the change in some major design parameters, as variation of the environment temperature, compressor pressure ratio, nitrogen supply ratio for the combustion chamber and gas turbine entry temperature.

Multi-species laser absorption sensors for in situ monitoring of syngas composition

Tunable diode laser absorption spectroscopy sensors for detection of CO, CO2, CH4 and H2O at elevated pressures in mixtures of synthesis gas (syngas: products of coal and/or biomass gasification) were developed and tested. Wavelength modulation spectroscopy (WMS) with 1f-normalized 2f detection was employed. Fiber-coupled DFB diode lasers operating at 2325, 2017, 2290 and 1352 nm were used for simultaneously measuring CO, CO2, CH4 and H2O, respectively. Criteria for the selection of transitions were developed, and transitions were selected to optimize the signal and minimize interference from other species. For quantitative WMS measurements, the collision-broadening coefficients of the selected transitions were determined for collisions with possible syngas components, namely CO, CO2, CH4, H2O, N2 and H2. Sample measurements were performed for each species in gas cells at a temperature of 25 °C up to pressures of 20 atm. To validate the sensor performance, the composition of synthetic syngas was determined by the absorption sensor and compared with the known values. A method of estimating the lower heating value and Wobbe index of the syngas mixture from these measurements was also demonstrated.

Choosing the Parameters of a Blast-Furnace Smelting Technology That Includes the Injection of Coal-Gasification Products

The use of a multi-zone mathematical model developed by the Institute of Ferrous Metallurgy of the Ukrainian Academy of Sciences to study blast-furnace smelting with the injection of coal-gasification products showed that additional coke can be saved by adding flux, increasing the temperature of the blast, and evenly distributing the ore burden across the top of the furnace. Keywords: coal-gasification products, mathematical model, replacement of coke, oxygen, carbon. A previous analysis of blast-furnace smelting technologies that include the injection of coal-gasification products (CGPs) showed that it is possible to significantly increase the amount of coal that can be injected if it undergoes preliminary gasification and the ash is fluidized in tuyere-mounted gasifiers (TMGs) (1). Coke consumption can be reduced by replacing high-grade coals having an ash content of up to 10% (and used in the blast furnace in the form of pulverized-coal fuel, or PCF) with low-grade coals containing up to 25% ash (and used in the blast furnace in the form of CGPs). When CGPs obtained from low-grade coals are injected, it is important to reduce coke consumption to a minimum (190-200 kg/ton) by also injecting PCF obtained from high-grade coals (2, 3). The key to a technology which entails CGP injection with the use of a TMG is equipping the knee-nozzle section of each blast-furnace tuyere with a device that gasifies PCF. The PCF is delivered to this device (gasifier) from the bustle pipe, with the PCF having previously been injected into the hot blast carried by the pipe. The CGPs formed in the gasifier are discharged from the TMG in the tuyere region and enter the tuyere hearth. Choosing efficient parameters for the smelting operation is part of the process of determining whether or not it is feasible to reduce coke consumption by the designated amount. The following are among these parameters when the furnace is to be injected with CGPs obtained from low-grade coals: 1) the temperature of the blast and its oxygen content, as well as the method used to supply the blast and oxygen needed for the gasification of coke and coal in the TMG: 2) the molar consumption of oxygen for gasification of the carbon in the coal, this parameter being calculated as the ratio O/C and expressed in moles/mole; and 3) the method employed to add more flux to the charge in connection with the increased amount flux consumed when high-ash coals are being used. The method used to supply the oxygen and blast needed for the gasification of coke and coal in the TMG is chosen based on the control parameters of the smelting regime and their set points. It has been proposed (1) that part of the oxidiz- ing blast which is sent directly into the furnace to burn coke be delivered via a separate channel that can be constructed in one of two variants: the use of a separate pipe to take a portion of the blast from the bustle pipe and transport it to the tuyere; the feeding of unheated oxygen through a pipe directly into the body of the tuyere to replace an equivalent amount of heat- ed blast. It was shown in (1) that hot blast can be replaced by unheated oxygen when the initial and projected unit consump-