Studying the temperature regime of the heliopyrolysis device reactor

. The article presents the principle of the heliopyrolysis device with a solar concentrator and the temperature measurement scheme at the characteristic points of the reactor. Pyrolysis of organic waste was carried out according to the experimental method in laboratory conditions. Experiments were carried out on samples of organic waste (rubber, polyethylene film, plastic bottle) with an initial moisture content of 5÷20% and a size of 4÷6 mm. Based on the relationship between the amount of solar radiation and the ambient temperature for the city of Karshi (Uzbekistan), the experimental results of studying the temperatures inside the heliopyrolysis reactor when various organic wastes are loaded are presented. 0.25h according to the height of the reactor in the experiment; 0.35h; 0.25h; temperatures on the inner surface at distances of 0.15 h were recorded using the Mobile-CASSY 2 thermometer. It was determined that an average temperature of 350÷450 ℃ can be generated in the reactor of the experimental device. Experiments show that in the conditions of the city of Karshi, it is possible to create a mode of 300÷500 ℃ sufficient for the pyrolysis of organic waste through a parabolic solar concentrator in the daytime mode.


Introduction
Currently, rational use of natural fuel resources and ensuring energy efficiency are important tasks.Effective use of renewable energy sources is important in saving energy resources.The energy potential of solar and biomass energy from renewable energy sources is large, and their practical use is energetically, ecologically and economically effective.can be effectively used for purposes [1].Currently, it is important to use solar concentrators to use solar energy in technological processes that require high temperatures.In recent years, in the world and in Uzbekistan, scientific studies on the use of solar energy in various technological processes have been conducted and practical results have been achieved [2][3][4][5][6][7][8].
Production of fuel and energy from biomass and organic waste using solar energy is primarily of interest to autonomous and long-distance energy consumers of centralized energy supply systems in the form of small rural settlements, farms and individual houses.Therefore, the processing of plant biomass for the production of fuel, heat and electricity is an important task, mainly to provide energy to the rural population, especially to energydeficient areas.
In recent years, scientific researches on the use of pyrolysis devices for obtaining alternative fuels from biomass indicate that significant theoretical and practical results have been achieved in this field.Currently, foreign scientists are conducting research on the use of solar concentrators in the pyrolysis process.For example, Zeng proposed a two-stage heliostat parabolic concentrator with a screen system to control the heating rate and temperature of the pyrolysis reactor.Their research investigated the effect of temperature (600÷2000 o C) and heating rate (5÷45 o C/sec) on the productivity and properties of solid coal obtained as a result of the process, not on the performance of the system in this period [9].In the experiments conducted by Seymon Sobek, the fundamentals of the pyrolysis process and the structure of existing solar pyrolysis reactors were investigated.A novel structure of laboratory-scale solar pyrolysis reactors has been developed to study biomass solar pyrolysis.Also, solar pyrolysis reactors operating with an artificial lighting system and pyrolysis reactors operating in constant sunlight were compared [10].Experiments conducted by Kuo Zeng investigated the solar pyrolysis of contaminated biomass to produce biogas.The study presents an updated modern method for the destruction of heavy metal-contaminated biomass by solar pyrolysis.In the solar pyrolysis reactor, the process was carried out at different temperatures (600, 800, 1000, 1200, 1400 and 1600 o C) and heating rates (10-50 o C/min) [11].Research by Ayala Cortes proposed a parabolic cylindrical concentrator for biomass pyrolysis heat generation.In this case, the pyrolysis reactor is made in a spherical shape and the temperature in it is ensured to be in the range of 450-1550 o C. The energy generated by the parabolic cylindrical concentrator was 25 kW.As a result, 1,4% of gas, 21% of solid coal and 77,6 % of liquid biofuels were obtained [12].Belarusian scientists from CIS countries the use of solar concentrators in biomass pyrolysis was studied by N.G.Khutskaya and I. G. Palchenok [13].In our republic, G.N. Uzakov, R.T.Rabbimov, X.A.Davlonov, Sh.Imomov conducted scientific research on obtaining alternative fuel from local biomass by pyrolysis method [14][15][16].
However, despite the results of the research, there are no sufficiently scientifically based results on the use of solar energy in increasing the energy efficiency of the pyrolysis device to obtain alternative fuel from biomass and organic waste energy.Therefore, it is important to substantiate the effectiveness of using solar devices for obtaining alternative fuel from organic waste in a pyrolysis device.The purpose of the study is to experimentally study the temperature regime of the reactor of the heliopyrolysis device.

Materials and methods
Ensuring the temperature regime in the reactor of the pyrolysis device is one of the main problems.Because in order to ensure the required (350÷500 o C) temperature regime of the reactor, energy (heat) must be supplied initially.It is usually done by using coal, natural gas or electricity as an energy source for the processes carried out in the pyrolysis unit.The reason is that it takes a lot of heat energy to decompose organic waste, and its additional heating requires excessive energy consumption.
In this research work, the dependence of the product yield on the temperature in the reactor for heliopyrolysis of organic waste was considered.An experimental heliopyrolysis device was created in the "Alternative energy sources" department of the Karshi Institute of Engineering and Economics to study the pyrolysis process.The experimental heliopyrolysis device consists of a tubular reactor, a condenser-cooler, a gas holder, a gas purification system, a parabolic concentrator and a pipe system (Figure 1).Pyrolysis of organic waste was carried out in laboratory conditions according to the following methodology.Before the start of the experiment, samples of organic waste (rubber, polyethylene film, plastic bottle) with an initial moisture content of 5÷20% and a size of 4÷6 mm were prepared.The mass of the loaded organic waste was measured with an electronic scale, and the moisture content was measured with an accuracy of ±2% using a digital universal AR971 moisture meter.The pyrolysis reactor ( 1) is made of a steel pipe with a diameter of 0,16 m, a height of 0,2 m and a useful volume of 0,003 m 3 .If the density of the biomass is 300 kg/m 3 and the moisture content is 15÷20%, 1 kg of raw material can be loaded into the reactor.Organic waste for pyrolysis is loaded through the lid of the reactor (4).The reactor is installed in the focus of the parabolic concentrator (13) and is heated through the bottom and converted into a steam-gas mixture.The resulting steam-gas mixture (5) passes through the pipe to the condenser (7), is cooled with water and condensed.Condensate of steam-gas mixture-liquid tar (bio-oil), i.e. liquid fuel (8) flows into a special container and is collected.The main part of the produced gas passes through (10) water gate and (12) active carbon filters and is collected in the gasholder.The main parameters of the parabolic concentrator heliopyrolysis device are listed in Table 1.In the experiment, the temperature profile of the pyrolysis process is created using a parabolic concentrator, where the heating rate of the loaded raw material was 5÷10 o C/min.Temperature regime in the reactor Mobile-CASSY 2 thermometer (measuring accuracy: ±3 °C, ±2 %; measuring range: -200 ...+200 °C/-200 ...+1200 °C), bimetallic thermometer Pakkens (measuring accuracy: CL 2.0; measurement range 0....+500 o C) and was monitored by thermal imager Snegir-700MT (measurement accuracy: ±2 °C; measurement range -20....+700 o C).Temperatures at characteristic points along the height of the cylindrical reactor were recorded using the Mobile-CASSY 2 thermometer (3).
Thermocouples 0,25h according to the height of the reactor; 0,35h; 0,25h; It was installed on the inner surface of the pipe at 0,15h points.The average temperature in the reactor was determined as follows: (1) Here, reactor temperatures at characteristic points, 0 С.As a result of pyrolysis of organic waste, combustible gas (biogas), high-energy liquid and coal are formed.The solid and liquid products formed in the process were measured with an electronic scale and the amount of biogas was measured with a gas measuring device.
Thus, the results of experimental studies on organic waste pyrolysis show that the amount of output of pyrolysis products depends on the process temperature, moisture and granulometric composition of the raw materials being loaded.
According to the conducted experiments, the pyrolysis of organic waste has a high intensity in the temperature range of 200÷450 o С, it was noted that the amount of liquid and gaseous fuels released during the pyrolysis process increases with increasing temperature.According to the analysis of the experimental results, it was found that the total output of pyrolysis products is less dependent on the temperature change in the temperature range of 350÷500 o C.

Results and Discussion
In this study, the dependence of the temperature at different points of the heliopyrolysis reactor on the value of solar radiation and the type of raw materials loaded was analyzed.
For the city of Karshi, the latitude angle is equal to 39 o , and as a result of the Meteonorm® meteorological database, the relationship between the amount of solar radiation falling on 1 m 2 of the surface and the ambient temperature during the year 2022 was determined (Figure 3).The heliopyrolysis method has a number of advantages over other heating methods, and is an energy-efficient and environmentally friendly method.The intensity of sunlight depends on the climatic conditions of the region and the position of the sun relative to the horizon, by which it is possible to ensure uniform heating of the surface of the heliopyrolysis reactor using solar concentrators.Tables 2, 3, and 4 present the experimental results of studying temperatures inside the heliopyrolysis reactor when various organic wastes are loaded.According to the results of the experiment, a reactor with a volume of 0,003 m 3 was selected.Experiments were conducted on rubber, polyethylene film and plastic bottles, which are considered organic waste.Based on this, the heliopyrolysis reactor was loaded with rubber pellets with dimensions of 4÷6 mm and moisture content of 5 %.It was found that the average temperature inside the reactor was 384,3 o C when the external temperature was 34 o C, the value of solar radiation was 980 W/m 2 , and the process lasted 150 minutes.On the next day, a polyethylene film with dimensions of 5÷10 mm and moisture content of 5% was pyrolyzed.According to the results, it was found that the average temperature inside the reactor was 370,6 o C when the external temperature was 36 o C, the value of solar radiation was 996 W/m 2 , and the process lasted 300 minutes.It was found that when a plastic bottle with dimensions of 5÷6 mm and humidity of 5 % was loaded into the heliopyrolysis reactor, the temperature of the external environment was 36 o C, the value of solar radiation was 1010 W/m 2 , and the average temperature inside the reactor was 364.56 o C, and the process lasted for 180 minutes.

Conclusion
As a result of researching the temperature profile of the reactor of the heliopyrolysis device, the results of the thermal treatment of organic waste at different temperatures were obtained.Experiments were carried out by alternately loading rubber, polyethylene film and plastic bottles into a reactor with a volume of 0,003 m 3 at the focus of a parabolic solar concentrator with an aperture surface of 2,54 m 2 .According to the results of the conducted experiment, when rubber was loaded into the heliopyrolysis reactor, the average temperature was 384,3 o C, when polyethylene film was loaded, the average temperature was 370,6 o C, and when a plastic bottle was loaded, the average temperature was 364,56 o C. By studying the temperatures at the characteristic points of the heliopyrolysis reactor, it was determined in experiments that the duration of the pyrolysis process depends on the temperature of the external environment, the type of product loaded, and the amount of solar radiation.In the climatic conditions of the city of Karshi, when the amount of solar radiation to the concentrator aperture was on average 700÷800 W/m 2 , as a result of the concentration of solar radiation on the surface of the reactor, the temperature was 450÷500 o C. Therefore, the proposed heliopyrolysis method allows to increase the energy efficiency of the device.The results obtained through the experiment can be used in the design and calculation of the heliopyrolysis device.

Fig. 2 .
Fig. 2. Scheme of measuring temperatures at characteristic points of the heliopyrolysis reactor.

Fig. 3 .
Fig. 3.The graph of the relationship between the amount of solar radiation and the ambient temperature in different months for the city of Karshi (as of 2022).

Fig. 4 .
Fig. 4. Graph of dependence of internal temperature on time and solar radiation when rubber is loaded into a heliopyrolysis reactor.

Fig. 5 .
Fig. 5. Graph of dependence of internal temperature on time and solar radiation when polyethylene film is loaded into a heliopyrolysis reactor.

Fig. 6 .
Fig. 6.Graph of dependence of internal temperature on time and solar radiation when plastic bottle is loaded into heliopyrolysis reactor.

Fig. 7 .
Fig. 7. Scale of temperatures at characteristic points of the reactor.

Table 1 .
Main parameters of heliopyrolysis device with parabolic concentrator.

Table 2 .
The results of studying the temperature of the heliopyrolysis reactor (rubber).

Table 3 .
The results of studying the temperature of the heliopyrolysis reactor (polyethylene film).

Table 4 .
The results of studying the temperature of the heliopyrolysis reactor (plastic bottle).