CC BY
4UDK 621 438 (0758)
VOLATILE SUBSTANCES FOR OBTAINING THERMAL PARAMETERS
OF COAL
RUSLAN UMIRZAKOV., ALMAGUL MERGALIMOVA
S. Seifullin Kazakh agrotechnical research university, Department "Heat Power Engineering», Aztana,, Kazakhstan
Annotation: The article discusses the theoretical and practical foundations of studying the possibility of obtaining volatile combustible substances released during special heat treatment of coal in order to replace burning fuel oil at thermal power plants. The results of an experimental study of coal from the Saryadyr field of three Kazakhstan fields in order to obtain volatile combustible substances, as well as the possibility of using these combustible substances as primary fuel, are given. The results of calculating the heat of combustion at different heating temperatures of gas obtained from the presented coal samples showed that with an increase in the heating temperature, the heat of combustion of combustible gases obtainedfrom coal samples also increases. The maximum value of the heat of combustion for all samples of coal under consideration is determined at a heating temperature of 600.°C. The maximum value is observed in the coal of the Shubarkol deposit - 22.1 MJ/m3, and in the brown coal of the Saryadyr deposit-the minimum value is 13.5 MJ/m3. According to the re 3epmmeynepd^ of experimental re earch, it i po ible to.
Keywords: burning coal, _ fuel tours, plasma ignition, crushed coal.
Currently, in Heat Power Engineering, fuel oil or natural gas is used when burning powder coal boilers and to stabilize the combustion (lighting) of powder coal torches. For these purposes, more than 50 million tons of fuel oil are spent annually in the world. The massive decline in the quality of steam coal requires an increase in fuel oil consumption at thermal power plants, and due to the deepening of oil refining, fuel oil production decreases. In Figure 1 shows a principled diagram of the use of fuel oil to burn the boiler and ensure a stable ignition of the pulverized coal flame [1,2].
Fuel oil as a fuel has a number of undoubted properties: high calorific value of 9500 kcal/kg, low ash content of 0.3-0.5%, the ability to obtain a burning flame (provides high radiation heat exchange in the furnace. space), the ability to organize combustion (under certain conditions) in small (by volume) furnaces. However, it also has a number of significant disadvantages. Fuel oil is an expensive fuel. At the moment, it value depend on the coal it elf.
Figure 1. Scheme of using fuel oil for burning a boiler and ensuring a stable ignition of a coal torch:
1-oil refinery, 2 - tank for collecting fuel oil, 3-burner for filling fuel oil from the tank. railway tank, 4-railway tank at the plant, 5-car tank at the TPP, 6-heating system for unloading fuel oil from the tank at the TPP, 7- fuel oil storage, 8-fuel oil heater in the warehouse, 9- fuel oil circulation system from the fuel oil storage to the fuel injector. vanadium oxides are 95e100 % if vanadium is only contained in fuel oil.
The combination of solid and liquid fuel accelerates high-temperature corrosion of heating surfaces and reduces the service life of factory equipment. Also, a significant
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disadvantage of fuel oil as a backup and primary fuel is the inconvenience caused by multistage preparation for combustion in boiler installations due to its operation. The indicated problem in the U E of fuel oil I in mall energy, with a capacity of under 35-75 t/ h, t
Alternative combustion method with plasma technology
The use of fuel oil at powdered coal TPPs seems to be nonsense that power engineers practically did not notice. A group of Kazakhstani scientists proposed a technology for using plasmotrons based on electrothermochemical preparation of solid fuel for combustion, in which electricity consumption is reduced several times (up to 1%). In particular, only the Chinese "Yantai Longyuan Power Technology Co. Ltd."the company alone has equipped more than 800 powder coal boilers with plasma torches for oil-free combustion. The power of boilers is different from 150 - 1000 MW [6,7].
In Figure 2 shows a schematic diagram of the use of a boiler plasma ignition system and stabilization of the combustion of a pulverized coal flame. The technology developed for its implementation and plasma fuel systems (POS) have been successfully tested at TPPs in Russia, Kazakhstan, Ukraine, Korea, China, Slovakia, Serbia and Mongolia in 31 boilers with a steam capacity of 75 to 950 t/h. with different dust preparation systems.
Figure 2. Scheme of operation of the system of plasma ignition of the boiler and stabilization of the combustion of powder coal flares at the CHPP:
1-coal warehouse, 2 — mill, 3-chamber for plasma thermochemical preparation of air mixture. , 4-plasmatrons, 5 - powder coal burner, 6-boiler combustion chamber.
POZH technology is based on plasma thermochemical preparation for burning coal. It consists in heating the air mixture (coal dust air) by electric arc plasma to the temperature of the volatile coal outlet and partial gasification of Coke residues. Thus, a highly reactive two-component fuel (combustible gas coke residue) is obtained from the primary coal. When mixed with secondary air in the boiler furnace, the two-component fuel ignites and burns steadily without additional fuel (fuel oil or gas), usually used to burn boilers and stabilize the combustion of pulverized coal flames.
aya i^ocnacbi
3- picture. Vortex PFS.
4-picture.. Direct flow PFS.
In a warm picture. Demonstration of drawings of the main types of development 3 and 4 direct-flow and Vortex POZ, reflecting the process of plasma thermochemical preparation for coal burning. From the images, it can be seen that a mixture of cold air (T< 350 K) enters the POH, which is heated to a high reactive two-component fuel formation temperature in
the plasma torch area. The latter burns intensively only in the boiler furnace, since all the oxygen in the air mixture is spent on partial gasification of coal carbon. In Figure 5 shows the cross - section of the RFC-210 boiler furnace with a capacity of 210 MW and brown coal consumption (humidity-40%, ash content 35% and combustion heat e 1900 Kcal/kg) of 250 t/h. The boiler is equipped with 48 single-pass powder coal burners, divided into 6 blocks and arranged in four tiers. 12 plasmotrons are installed in the muffle channels of low-level burners, ensuring the ignition of brown coal through each channel at a flow rate of up to 7.25 t/h.
Plasma ignition technology industry
Figure 5. Scheme of the technology of obtaining and supplying flammable flying substances to the boiler plant.
1 dump truck, 2 receiving Hopper, 3 belt conveyor, 4 electromagnetic separators, 5 vibration screens, 6 hammer crushers, 7 raw coal hopper, 8 furnaces for heating coal, 9 exhaust enriched coal Mass, 10 gas shut-off valves, 11 electric valves, 12 mechanical filters, 13 gas pressure regulators; 14 pressure relief valves, 15 bypass lines, 16, 20 flow meters, 17 gas regulating valves, 18 gas burners, 19 plug valves, 21 high-speed gas valves, 22 flow regulator covers, 23 gas storage-receiver, 24 fuses, 25 fans
High fuel oil prices, its shortage, a number of negative consequences of a technical, economic and environmental nature, difficulties in operation associated with its use significantly affect the reduction in the share of fuel oil in the fuel balance of powder coal boilers. An urgent task of the heat power industry both in Kazakhstan and on a global scale.
Our proposed method of burning coal with volatile combustible substances obtained by heat treatment
It is known that coal is significantly inferior to natural gas and oil costs for its own needs, especially in terms of environmental indicators. However, according to the estimates of the International Energy Agency [3], at the current rate of consumption, explored oil reserves will be exhausted in 30 years, and gas - in the next 50 years (but Kazakhstan has a more favorable future [4]), and coal reserves will last for 200 years with the most intensive use [5]. Currently, no one has any doubts about the need to develop coal technologies. The remaining fuel re ource are u ed for a much Hort term.
SPISOK USED EASTERS
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