scholarly journals Features of Pyrolysis of Plant Biomass at Excessive Pressure

2021 ◽  
Author(s):  
Sergey Vasilevich ◽  
Dmitry Degterov

The paper describes methods for producing charcoal (highly porous carbon materials) based on plant (wood) raw materials, and the equipment used to implement these processes, the use of activated carbons. The paper describes results of an experimental study of the effect of pressure on the formation of charcoal in the pyrolysis of birch chips. The experimental investigation was carried out at pressures of 0.1, 0.3, 0.5, 0.7 MPa. To investigate the effect of pressure on the pyrolysis process, a laboratory bench was designed and constructed. It was found that increasing the pressure from 0.1 MPa to 0.7 MPa increases the yield of charcoal from 25.1 to 32.4% by weight (relative to the dry weight of the starting material) and the carbon content from 89.1% by weight at 0.1 MPa to 96.4% by weight at 0.7 MPa. The calorific value of charcoal decreases from 34.86 MJ/kg at a pressure of 0.1 MPa to 30.23 MJ/kg at a pressure of 0.7 MPa. This is due to the release of oxygen-containing components, which have a higher calorific value than pure carbon, from the porous coal structure. Reduction of the charcoal heat combustion with a decrease in the amount of oxygen-containing components confirms conclusion that their calorific value exceeds the calorific value of pure carbon.

Author(s):  
А.А. Спицын ◽  
И.И. Белоусов ◽  
Т.Б. Турсунов ◽  
В.А. Хен

Рассмотрены аппарат уплотнения с частичной химической переработкой сырья и инновационная технология получения гранулированного активированного углеродсодержащего продукта и жидкого биотоплива методом уплотнения (пеллетирования) предварительно измельченного сырья, ускоренного гидролиза, пиролиза, с последующей активацией. Приведены результаты апробации технологии на стендовых установках и аппаратах. Показано, что по- лученные гранулы соответствуют основным показателям отечественных и за- рубежных стандартов на пеллеты из растительного сырья. В процессе произ- водства протекает химическая модификация исходного сырья, на что указывает повышенное значение содержания лигнина в образцах. При проведении пиро- лиза полученных пеллет производятся гранулированный углистый остаток, жидкое биотопливо и горючая парогазовая смесь. Из гранулированного угли- стого остатка получены активированные угли, имеющие адсорбционную активность по йоду, сравнимую с древесным углем марки ДАК. Одним из направлений дальнейших исследований является подбор различных добавок в сырье перед проведением уплотнения и грануляции для улучшения свойств пеллет, в частности повышения теплотворной способности и уменьшения зольности. Однако наиболее интересное направление использования уплотненных отходов растительной биомассы в виде пеллет – в качестве сырья для термохи- мической переработки с целью получения энергетически плотных продуктов, в частности пиролиза. Исследование показало целесообразность разработки единой автономной технологии переработки отходов растительной биомассы с по- лучением конкурентно-способных товарных продуктов: гранулированных активированных углей, жидкого биотоплива, а также парогазовой смеси с достаточной теплотворной способностью для обеспечения работы специальных топочных устройств. The paper deals with the sealing machine with partial chemical processing of raw materials and the innovative technology for obtaining granular activated carbon- containing product and liquid biofuel by the method of compaction (pelletizing) of pre-crushed raw materials, accelerated hydrolysis, pyrolysis and subsequent activation. The results of approbation of the technology on bench installations and devices are presented. It is shown that the obtained pellets correspond to the main indicators of domestic and foreign standards for pellets from vegetable raw materials. In the production process, a chemical modification of the feedstock takes place, as indicat- ed by the increased value of lignin content in the samples. When pyrolysis of the pellets is produced, a granular carbonaceous residue, liquid biofuel, and a combustible gas-vapor mixture are produced. From the granular carbonaceous residue, activated carbons with an adsorption activity of iodine comparable to charcoal of the DAK brand were obtained. One of the directions of further research is the selection of various additives into the raw material before compaction and granulation to improve the properties of pellets, in particular, to increase the calorific value and to reduce ash content. However, the most interesting direction of using compacted biomass res- idue in the form of pellets is to use as a raw material for thermochemical processing in order to obtain energetically dense products, in particular pyrolysis. The work showed the expediency of developing a single autonomous technology for plant biomass residues processing with the production of competitive commodity products: granular activated carbons, liquid biofuel, as well as steam-gas sweep with sufficient calorific value to ensure the operation of special combustion devices.


Eksergi ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 13
Author(s):  
Sri Wahyu Murni ◽  
Tutik Muji Setyoningrum ◽  
Muhamad Maulana Azimatun Nur

Indonesia biomass waste is a potential feedstock as a source of renewable energy since it can be converted into carcoal briquettes. However, the production of the briquettes using pyrolysis process using the agricultural waste was lacking. In this research, briquette was made from palm shells,  corncob and soybean stem wood due to its high availability and have high cellulose content. The purpose of this research was to produce briquettes from three kind of raw materials by employing pyrolysis process and compared the characteristics. The briquette was made from different type of raw materials (palm shells, corncob and soybean stem) and  the concentration of binder : 3-7 %. Pyrolysis was done at  500 °C, and 100 kg / cm2 of pressing pressure. Results showed that, the best charcoal briquette was achieved from palm shells by using 5% binder, which resulted 4,1% moisture content, 3.4% ash content,  15% volatile matter content, 77.5% carbon content,  7075 cal/g calorific value and  1.4 kg/cm2 compresive strength. It is found that the concentration of binder and raw material influenced the quality of the briquettes. In overall, the production of the briquettes by employing pyrolysis method could meet the standard.


Author(s):  
Magdalena DĄBROWSKA ◽  
Milena JAWOREK ◽  
Adam ŚWIĘTOCHOWSKI ◽  
Aleksander LISOWSKI

Wastes from forest and agricultural industry are still insufficiently used. One of the ways of their preprocessing is a pyrolysis process. Therefore, the aim of this study was to determine the energetic properties of biochar made of walnut shells, forest wood chips and willow chips. The studies were performed according to standards. The moisture contents of the material, the ash contents, the net and gross calorific values were determined. Low moisture and ash content were found in each of the biochar species. For all tested samples the ash contents were lower than 6% and for forest wood chips it was 1.5% only. The way of processing the biomass in the pyrolysis process significantly increased the calorific value of the raw materials. It was found that the net calorific values of the tested materials were high and reached the amount of 26.58 MJ‧kg-1 for biochar made of walnut shells, 22.29 MJ‧kg-1 for biochar made of forest wood chips and 24.59 MJ‧kg-1 for biochar made of willow chips. Due to the good physical properties of biochar produced from waste and biological materials, it was found that these solid fuels can be used for energy purposes.


2021 ◽  
Vol 4 (2(60)) ◽  
pp. 16-21
Author(s):  
Andrii Maksymenko

The object of research is the control system for the pyrolysis reactor of agricultural waste (plant biomass). The subject of research is the stability and the value of the calorific value of synthesis gas formed by pyrolysis of plant biomass. The biggest problem of the technological object (the pyrolysis reactor of agricultural waste) is the high sensitivity of the heating value of synthesis gas to disturbances in the composition of plant biomass. This sensitivity is expressed as a square law of the amount of oxidant required to achieve a high calorific value. Another problem is the deviation of certain time constants of the control object, caused by changes in the chemical composition of the plant biomass. The built control system provides a high calorific value of the generated syngas by determining the composition of the waste, pyrolysis by determining the composition of the generated syngas in a separate isoenthalpic device, and stabilizes it. Information on the composition of raw materials allows to calculate the optimal parameters for the pyrolysis process, and, accordingly, update the controller's task. This information also makes it possible to compensate for changes in the time constants of the control object caused by changes in the chemical composition of raw materials, which made it possible to achieve a high robustness of the system. Compensation for these changes was carried out by training a regression polynomial. The training was carried out on test sets of time constant deviations. The resulting polynomials were used for convolution with membership functions of a fuzzy controller. Such a convolution made it possible to obtain the following membership functions that ensure compliance with the control quality parameters close to those obtained without deviations in the time constants. Simulation of the constructed control system showed a significantly reduced sensitivity of the calorific value to the composition of raw materials, and also revealed a low sensitivity of the control quality from the deviations of the time constants of the control object caused by disturbances in the chemical composition of the waste. The method by which the control system for the pyrolysis reactor was built differs from the existing ones in that the use of information on the composition of the pyrolyzed substance is used to accurately calculate the optimal values of the pyrolysis parameters, as well as to mutate the membership functions of the fuzzy controller. The method can be used in other similar systems designed for the pyrolysis of organic substances in order to expand their scope. In particular, for the integration of such systems into technological objects, they are more sensitive to deviations in the calorific value of the gas used as fuel.


Author(s):  
S. V. Vasilevich ◽  
M. V. Malko ◽  
D. V. Degterov ◽  
A. N. Asadchyi

A method is presented for obtaining activated carbons (highly porous carbon materials) based on plant (wood) raw materials using a developed and manufactured experimental setup, consisting of a steam generator, a superheater, a pyrolysis and activation chamber and a cooler with a heat exchanger with forced convection. The analysis of the features of chemical and physical activation of charcoal, obtained by pyrolysis of wood raw materials, is carried out, and a conclusion is made about the advantage of physical activation, based on the use of water vapor as an activating agent. A description of the results of experimental studies carried out using the developed installation is given. These results confirm the conclusions of other studies that excessive pressure increases the mass yield of solid products formed during the thermochemical conversion of plant biomass. It was found that an increase in pressure, at which pyrolysis occurs, leads to an increase in the carbon content in charcoal. So, with an increase in pressure at which pyrolysis was carried out, from 1 to 8 atm, the carbon content in charcoal increased from 88.3 to 93.7 wt.%. Data on the efficiency of physical activation of solid products of pyrolysis of woody biomass using water vapor are presented and a conclusion is made that this direction is promising in the development of the foundations for the production of highly porous carbon materials.


Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4898
Author(s):  
Bogdan Saletnik ◽  
Marcin Bajcar ◽  
Aneta Saletnik ◽  
Grzegorz Zaguła ◽  
Czesław Puchalski

The article discusses the findings related to the calorific value as well as the explosion and combustion parameters of dust from the raw biomass of fruit trees, i.e., apple, cherry, and pear branches, and from biochars produced using this type of biomass during pyrolysis processes conducted under various conditions. The plant biomass was thermally processed at 400, 450, or 500 °C for a duration of 5, 10, or 15 min. The study aimed to identify the calorific value of the biomass obtained from waste produced in orchards and to estimate the explosion hazard during the processing of such materials and during the storage of the resulting solid fuels. Tests were conducted to assess the total contents of carbon, ash, nitrogen, hydrogen, and volatile substances as well as the calorific value. The findings show a significant effect of the thermal transformation of fruit tree branches on the calorific value of the biochars that were produced. It was found that the mean calorific value of all of the biochars was increased by 62.24% compared to the non-processed biomass. More specifically, the mean calorific values of the biochars produced from apple, cherry, and pear branches amounted to 27.90, 28.75, and 26.84 MJ kg−1, respectively. The maximum explosion pressure Pmax measured for the dust from the biomass and for the biochars was in the range 7.56–7.8 and 7.95–11.72 bar, respectively. The maximum rate of pressure rose over time (dp/dt)max in the case of the dust from the biomass, which was in the range of 274.77–284.97 bar s−1, and the dust from biochar amounted to 282.05–353.41 bar s−1. The explosion index Kst max measured for non-processed biomass and biochars was found to range from 74.46 to 77.23 and from 76.447 to 95.77 bar s−1, respectively. It was also shown that a change in the temperature and duration of the pyrolysis process affected the quality of the biochars that were obtained. The findings show that pyrolysis, as a method of plant biomass processing, positively affects the calorific value of the products and does not lead to an increased risk of explosion during the treatment and storage of such materials. It is necessary, however, to continue research on biomass processing in order to develop practices that adequately ensure safety during the production of novel fuels.


2019 ◽  
Vol 5 (12) ◽  
pp. 26-36
Author(s):  
Yu. Lugovoy ◽  
N. Antonov ◽  
K. Chalov ◽  
A. Stepacheva ◽  
Yu. Kosivtsov ◽  
...  

Describes the processes of thermal conversion of soft– and hardwood waste to obtain gaseous, liquid and solid products. During the initial stage of the work, the thermogravimetric study of initial samples of birch and pine sawdust was performed in the temperature range from 35 to 1000 °C. On the basis of the thermal analysis data obtained, a method of pyrolysis process of wood waste in the temperature range of 400–500 °C in an inert environment was developed. As a result of experiments on pyrolysis of wood waste, the dependence of the conversion of selected samples into final products, the properties of the resulting gaseous and solid carbon-containing products depending on the conditions of the process, the size of the fraction and the type of wood were obtained. It was found that the optimal temperature of the pyrolysis process in the studied range of system parameters is 450 °C, and the particle size of wood waste is 1–2 mm. Data on the molecular mass distribution of volatile pyrolysis products and kinetic parameters of the pyrolysis process were obtained. The activation energies of the pyrolysis process for pine and birch sawdust samples were 119.3 and 128.2, respectively. The specific surface area of the initial samples of birch and pine wood waste was 9.3 and 8.5 m2/g, respectively. The specific surface area of coal pyrolysis residues for hardwoods increased by 2.4 times and for conifers by 2.1 times, respectively, and assumed values of 22.3 and 17.9 m2/g. Therefore, the coal residues of pyrolysis of wood waste can potentially be used as raw materials for the production of activated carbons and carbon sorbents of various applications.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 485b-485
Author(s):  
Lisa M. Barry ◽  
Michael N. Dana

Nurse crops are often recommended in prairie restoration planting. This work investigated several alternative nurse crops to determine their utility in prairie planting. Nurse crops were composed of increasing densities (900, 1800, or 2700 seeds/m2) of partridge pea, spring oats, spring barley, Canada wild rye, or equal mixtures of partridge pea and one of the grasses. The experimental design was a randomized complete-block set in two sites with three blocks per site and 48 treatments per block. Each 3 × 3-m plot contained 1 m2 planted in Dec. 1995 or Mar. 1996 with an equal mix of seven prairie species. The nurse crops were sown over each nine square meter area in April 1996. Plots lacking nurse crops served as controls. Evaluated data consisted of weed pressure rankings and weed and prairie plant dry weight. Nurse crop treatments had a significant effect on weed pressure in both sites. Barley (1800 and 2700 seeds/m2) as well as partridge pea + barley (2700 seeds/m2) were most effective at reducing weed pressure. When weed and prairie plant biomass values were compared, a significant difference was observed for site quality and planting season. Prairie plant establishment was significantly greater in the poorly drained, less-fertile site and spring-sown plots in both sites had significantly higher prairie biomass values. Overall, after two seasons, there was no advantage in using nurse crops over the control. Among nurse crop treatments, oats were most effective in reducing weed competition and enhancing prairie plant growth.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4960
Author(s):  
Adam Koniuszy ◽  
Małgorzata Hawrot-Paw ◽  
Cezary Podsiadło ◽  
Paweł Sędłak ◽  
Ewa Możdżer

Biomass from cup plant (Silphium perfoliatum L.) is considered a renewable energy source that can be converted into alternative fuel. Calorific syngas, a promising type of advanced fuel, can be produced through thermochemical biomass gasification. In this study, the suitability of cup plant biomass for gasification was assessed, including the process energy balance and environmental impacts of waste from syngas purification. Silphium perfoliatum L. was cultivated as a gasification feedstock in different conditions (irrigation, fertilization). The experiments were performed in a membrane gasifier. All obtained energy parameters were compared to the biomass yield per hectare. The toxic effects of liquid waste were assessed using tests analyzing germination/seed root elongation of Sinapsis alba. Leachates collected from condensation tanks of a gas generator were introduced to soil at the following doses: 100, 1000 and 10,000 mg kg−1 DM of soil. The usefulness of Silphium perfoliatum L. for gasification was confirmed. The factors of plant cultivation affected the biomass yield, the volume and calorific value of syngas and the amount of biochar. It was determined that the components found in condensates demonstrate a phytotoxic effect, restricting or inhibiting germination and root elongation of Sinapsis alba. Due to this potential hazard, the possibility of its release to the environment should be limited. Most of the biomass is only used for heating purposes, but the syngas obtained from the cup plant can be used to power cogeneration systems, which, apart from heat, also generate electricity.


2020 ◽  
Vol 11 (1) ◽  
pp. 188
Author(s):  
Piotr Skałecki ◽  
Agnieszka Kaliniak-Dziura ◽  
Piotr Domaradzki ◽  
Mariusz Florek ◽  
Ewa Poleszak ◽  
...  

The aim of the study was to assess the influence of the addition of fish raw materials (roe or fish meat) on the quality and nutritional value of pork pâtés. The control group (n = 4) consisted of pork pâtés, I experimental group (n = 6) of pâtés with 20% addition of roe (perch and pike), and II group of pâtés with 20% addition of fish (perch and pike meat) (n = 6). The pâtés’ pH, color, and profiled texture analysis were instrumentally measured and water, protein, fat, ash, and fatty acid content were determined by reference methods. To assess the oxidative stability of lipids the measurement of peroxide number, thiobarbituric acid reactive substances and content of conjugated dienes and trienes was used. The degree of fat hydrolysis was determined on the basis of acid value. Sensory analysis was carried out using the scaling method, taking into account 12 unit quality characteristics. Products with roe and meat contained less fat (accordingly 15.9% and 14.1%) and showed lower calorific value (accordingly 225.6 and 208.6 kcal/100 g) compared to pork pâtés (20.2% of lipids, 267 kcal/100 g). Moreover, the addition of fish raw materials improved the index of nutritional quality for protein (from 3.2 to 3.9) and beneficially reduced the nutritional index for fat (from 2.2 to 1.9). Fish constituents modified, to a certain extent, the color, texture, and sensory properties of pâtés, while maintaining full acceptability in consumer assessment. The addition of fish roe significantly increased the healthful quality by improving the fatty acid profile of pâtés, in which the significantly highest content of n-3 fatty acids, including eicosapentaenoic and docosahexaenoic acids (accordingly 252.21, 43.17, and 107.94 mg/100 g product), as well the highest concentration of saturated branched chain fatty acids were determined (18.75 mg/100 g product).


Sign in / Sign up

Export Citation Format

Share Document