Simulasi co-combustion batubara dan biomassa tandan kosong kelapa sawit tertorefaksi (torrefied biomass)

Coal is still widely used as the main fuel in the industry, especially the power generation industry (PLTU), cement plants and etc. Coal is a fossil fuel whose availability is thinning and its fires produce CO2 emissions that cause a rise in greenhouse gas (GHG) concentricity. On the other biomass is an alternative energy source that is abundant, including empty bunches of oil palm (TKKS), but has poor combustion properties compared to coal when burned directly. The properties of biomass burning can be improved by certain treatment, one of which is through the process of torrefaction. Biomass torrefaction has a calorific value equivalent to sub-bituminous coal B, so it has the potential to be used as an alternative fuel for coal. The purpose of this study was to determine the maximum temperature that occurs in the burner. In this study co-combustion was conducted on simulation of ANSYS program with powder system (pulverized combustion) because this type in recent decades is widely used in industry. In this study conducted a simulation on ANSYS to determine the temperature on the burner and the concentration of emissions produced. The results showed that the simulation of co-combustion burner burner showed the maximum temperature reached 970°C. The effect of burner and burner temperature in the form of swirl provides sufficient oxygen with more perfect combustion resulting in decreased concentration of CO2 emissions and low concentration of N2 due to higher nozzle temperature. High temperatures lower the concentration of SO2 in the burn chamber.Keyword: Co-combustion, pulverized co-combustion simulation, TKKS torrefaction, burner.

Predicting changes in the sulfur content during steam coal preparation and the level of sulfur dioxide emissions when its combustion

Purpose. Development of a method and forecast estimation of sulfur dioxide emission reduction during combustion of steam coal by regulating its quality during coal preparation. Methodology. Study on sulfur content in coal using sieve, fractional analysis, analysis of ash and total sulfur content. Forecasting of sulfur content in concentrate according to the developed calculation method. Production tests at the coal preparation plant. Forecasting of the level of SO2 emissions during pulverized coal combustion according to the developed calculation method. Findings. The distribution of sulfur content of Ukrainian steam bituminous coal by size classes depending on ash content is investigated; the proximity of sulfur content to the linear dependance on the ash content of the run-of-mine coal, rock-free substance, rock and concentrate is proved. The calculations of the level of SO2 emissions during pulverized combustion of coal and its cleaned products taking into account their elemental composition is performed, and the linear dependence of the level of SO2 emissions on the total sulfur content to lower heating value (LHV) ratio is proved. Based on the obtained results, methods are developed for determining the expected sulfur content in the concentrate and the forecasted level of SO2 emissions during its combustion; the optimal depth of preparation for the coal from various mines is determined by the criterion of compliance of the SO2 emission level with the current environmental standards. Originality. Proximity of the sulfur content to the linear dependence on the ash content of the run-of-mine coal, rock-free substance, rock and concentrate is proved. The linear dependence of the level of SO2 emissions on the ratio of the total sulfur content to LHV during pulverized combustion of coal and its clean products is proved. Practical value. A method has been developed for determining the expected sulfur content in the products of coal preparation by jigging, taking into account the allowable content of the high-density fraction in the concentrate and adding dense slimes to the coal preparation products. A method has been developed for determining the predicted level of SO2 emissions during their combustion. The optimal depth of the coal preparation for coal from various mines has been determined by the criterion of compliance of the level of SO2 emissions with the current environmental standards.

ELECTRIC PULSE METHOD FOR PRODUCING A SMALL-DISPERSED PRODUCT OF COAL-WATER FUEL

One of the most pressing issues is the effective use of coal combustion in the form of water-coal fuel, which has a number of advantages over layer or pulverized combustion. Coal-water fuel has a number of economic, operational and environmental advantages. The article considers the electric pulse method as a source of obtaining a fine product of coal-water fuel. The proposed method for grinding coal is based on the use of the energy of a pulsed shock wave resulting from a spark electric discharge in a liquid. The parameters of the electric pulse discharge for obtaining the required granulometric composition of the components of coal-water fuel are determined.

Crush and Acid Resistance of Microsphere Narrow Fractions from Fly Ash as the Basis of Composite Materials

The crush test and acid resistance of microsphere narrow fractions with average diameter dav of 5, 8 and 25 μm of the SiO2–Al2O3–FeO system and with dav of 4 and 10 μm the CaO–SiO2–Al2O3– FeO system separated from fly ash from pulverized combustion of Ekibastuz and Irsha-Borodinsky coals were studied. It has been established that all investigated ash fractions of both raw materials are characterized by high strength: microspheres of a larger narrow fraction with dav = 25 μ m a re not destroyed by compressive loading at pressures up to 51.7 MPa, dispersed narrow fractions of microspheres with dav ≤ 10 μm – up to 68.9 MPa. Microsphere narrow fractions with aluminosilicate composition have satisfactory acid resistance; the weight loss after treatment with 15 % hydrochloric acid at 65 °C for 30 minutes was 10–15 wt. %

Laboratorijskim istraživanjem do izbora mjesta uvođenja stepenovanog vazduha za sagorijevanje u ložište

In general, the mixing the reactants is very important to the process and the rate of combustion of each fuel, especially low-ranked coals with low reactivity. The appropriate excess air coefficient for combustion and the position and mode of supply of individual portions (air sta- ging) of the total air in the furnace are one of the key influ- encing factors for the mixing, respectively the efficiency of the combustion process, and the level of emissions. Today, the air staging (primary, secondary, tertiary and over fire air-OFA) is an indispensable process in the design of new industrial and energy boilers. Also, this measures are used for the reconstru- ction of existing furnace of large boilers. The implementation of this primary measure in the furnace does not require signi- ficant financial resources - the costs of investing in the intro- duction of air staging supply for combustion in the furnace are very low in relation to the multiple positive effects and bene- fits of such a system, especially a lower NOx emissions. However, the first condition for the correct and reliable design of the air staging system in the furnace is the choice of the optimal position for the supply OFA air. Determination of this position on the furnace depends on several factors, primarily the type and characteristics of the fuel, grinding quality, co- mbustion technology, furnace structure, type, number and arra- ngement of burners. On this topic, the Faculty of Mechanical Engineering of the University of Sarajevo, in the Laboratory for Coal and Biomass Combustion, conducted extensive rese- arch on the pulverized combustion of coal blends of the Ce- ntral Bosnia Mining Basin, including co-firing of these coals with waste wood biomass (beech and spruce sawdust). Here is presented some of the results of those NOx emission studies for different fuels and combustion temperatures, depending on the mode of supply and the positions of the combustion air supply in the boiler furnace.