Optimization of process variables for briquetting of biochar from corn stover

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6811-6825
Author(s):  
Wenqiao Jiao ◽  
Lope Galindo Tabil ◽  
Mingjin Xin ◽  
Yuqiu Song ◽  
Bowen Chi ◽  
...  

Instead of compressing biomass into briquettes, this study considers the compression of biochar. Densification is necessary for biochar to increase bulk density for convenience of handling, transportation, and storage. Response surface methodology was employed, and briquetting of biochar from corn stover was carried out in this study to investigate the effects of moisture content (at levels of 16, 17.6, 20, 22.4, and 24%), pressure (at levels of 21.5, 25, 30, 35, and 38.5 MPa), and residence time (at levels of 4, 6.4, 10, 13.6, and 16 s), on crushing resistance, dimensional stability of briquettes, and specific energy consumption of briquetting. The results showed that the effects of the variables on each evaluation index were significant (P < 0.01), the influence order was obtained, and the regression models are set up. The optimum condition for the briquetting process was moisture content of 18.5%, pressure of 38.5 MPa, and residence time of 4 s, giving mean values of the briquette crushing resistance of 49.9 N, dimensional stability of 93.8%, and specific energy consumption of briquetting of 4.41 MJ/t, respectively. The errors between the predicted values and the experimental values are all less than 5%.

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  


2014 ◽  
Vol 10 (2) ◽  
pp. 269-280 ◽  
Author(s):  
Hosain Darvishi ◽  
Mohammad Zarein ◽  
Saied Minaei ◽  
Hamid Khafajeh

Abstract The energy and exergy analysis, drying characteristics and mathematical modeling of the thin-layer drying kinetics of white mulberry using microwave drying were investigated. Results indicated that values of exergy efficiency (33.63–57.08%) were higher than energy efficiency (31.85–55.56%). Specific energy consumption increased with increasing microwave power while improvement potential decreased. The specific energy consumption and improvement potential varied from 3.97 to 6.73 MJ/kg water and 0.71 to 2.97 MJ/kg water, respectively. Also, energy efficiency decreased with decrease in moisture content and microwave power level. The best exergy and energy aspect was obtained by drying at 100 W microwave power. Drying took place mainly in warming up, constant rate and falling rate periods. The Page model showed the best fit to experimental drying data. Effective diffusivity increased with decreasing moisture content and increasing microwave power. It varied from 1.06 × 10−8 to 3.45 × 10−8 m2/s, with an energy activation of 3.986 W/g.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9429-9443
Author(s):  
Xiaoxue Du ◽  
Hanping Mao ◽  
Chunguang Wang

The rheological properties of the compression process of sweet sorghum straw were studied. The selected experimental factors comprised of the compression density, cutting length, compression speed, and moisture content, and specific energy consumption were selected as the evaluation index of the compression characteristics. The Box-Behnken test scheme was used to analyze the response surface test. The results showed that the selected compression model and specific energy consumption model of the sweet sorghum straw compression process were obtained. The primary factors contributing to energy consumption were the cutting length, moisture content, and compression density. The optimal parameters were as follows: a compression density of 500 kg/m3, a cutting length of 20 mm to 30 mm, a moisture content of 60.06%, and a specific energy consumption of 66 kJ/kg. The results provided methods for reducing the total energy consumption of the compression process and a theoretical basis for the compression and bundling of sweet sorghum.


2010 ◽  
Vol 5 (4) ◽  
Author(s):  
Guihe Tao ◽  
Kiran Kekre ◽  
Maung Htun Oo ◽  
Bala Viswanath ◽  
Aliman MD Yusof ◽  
...  

One of the major components of MBR operating expenditure is energy consumption. This paper presents our six-year journey of energy reduction and optimization in MBR systems through various pilot and demonstration studies. Through comprehensive and systematic MBR optimisation studies, the specific energy consumption was reduced from 1.3 kWh m−3 to less than 0.8 kWh m−3 by increasing membrane flux and reducing aeration at 300 m3 per day pilot scale plants. Through energy audit, the key energy consumption components including process aeration, membrane scouring rate, SRT, MLSS level, MLSS recirculation, and energy efficient equipment selection were identified, and these were optimised one by one at 23,000 m3 per day municipal scale MBR demonstration plant after the baseline had been set up. The specific energy consumption was further reduced to 0.37 kWh m−3.


2020 ◽  
Vol 7 (3) ◽  
pp. 163-170
Author(s):  
Irwansyah Irwansyah ◽  
Leopold Oscar Nelwan ◽  
Dyah Wulandani

Artificial drying method for arabica coffee beans requires a large consumption of electrical energy. Electricity is needed to rotate the blower which functions to circulate hot air to the dryer so that it can evaporate some of the water contained in the coffee beans. Most of the arabica coffee producing areas in Aceh province have not been reached by the electricity network so the use of artificial dryers cannot be used. To overcome this obstacle, the air flow circulation system with chimney effect can be used to drain dry air. The aim of this research is to design a chimney effect hybrid dryer which is heat source from solar and biomass energy, to test the performance of the dryer and compare it with the sun drying method. Parameters observed were temperature, moisture content and specific energy consumption of solar radiation and biomass. Dryer capacity is 5 kg of arabica coffee beans. The results showed that the chimney effect hybrid dryer can be used to dry 5 kg of coffee beans. The drying show that drying temperature on the dryer chamber ranged between 37.3-60.9°C. To reduce the moisture content of coffee beans from 52.5 to 12.8% bb, it was take 16-17 hours, while the sun drying method takes up to 46 hours (6 days). The total specific energy consumption of hybrid dryer was 57.1 MJ/kg of water vapor, while the specific energy consumption of the drying method was 59.4 MJ/kg of water vapor.


2012 ◽  
Vol 622-623 ◽  
pp. 1580-1585
Author(s):  
A. Sae-Khow ◽  
S. Tirawanichakul ◽  
Y. Tirawanichakul

The objective of this research were to evaulate equilibrium moisture contents (EMC) of black pepper using the gravimetric-static method and to study the drying kinetics of pepper using 1-stage hot air (HA) drying, 1-stage infrared (IR) drying, 2-stages drying with microwave (MW) and IR and 2-stages drying with MW and HA including to the specific energy consumption determination. For the first objective, the five saturated salt solutions were used for providing equlibrate state between pepper and surrounding at temperature ranging of 40-65°C correlated to relative humidity ranging of 10-90%. The results showed that EMC value decreased with increasing temperature at constant relative humidity. To evaluate the EMC value, the experimental data was simulated by four conventional EMC models and the criteria of the best fiiting models were determined by the determination of coefficient (R2) and the root mean square error (RMSE) value. The results showed that the calculated value using the Modified Oswin model was the most suitable for describing the relationship among equilibrium moisture content, relative humidity and temperature. To study effect of drying condition on drying kinetics, the initial moisture content and final moisture content after drying of papper sample was in ranges of 300-400% dry-basis and 12-16% dry-basis, respectively. The experimetal data were simulsted using empirical drying models and the results showed that the drying temperature relatively affected to drying rate of pepper while the evolution of moisture transfer was in the drying falling ratefor all drying strategies. The 1-stage IR drying and 2-stages drying with MW and IR provided low specific energy consumption (SEC) (0.11-0.15 MJ/kg of water evaporated) compared to the other drying strategies (0.87-1.52 MJ/kg of water evaporated). Moreover, the SEC of pepper drying decreased with increasing of drying temperature.


2019 ◽  
Vol 6 (1) ◽  
pp. 12 ◽  
Author(s):  
Jaya Tumuluru ◽  
Dean Heikkila

Biomass could be a key source of renewable energy. Agricultural waste products, such as corn stover, provide a convenient means to replace fossil fuels, such as coal, and a large amount of feedstock is currently available for energy consumption in the U.S. This study has two main objectives: (1) to understand the impact of corn stover moisture content and grinder speed on grind physical properties; and (2) develop response surface models and optimize these models using a hybrid genetic algorithm. The response surface models developed were used to draw surface plots to understand the interaction effects of the corn stover grind moisture content and grinder speed on the grind physical properties and specific energy consumption. The surface plots indicated that a higher corn stover grind moisture content and grinder speed had a positive effect on the bulk and tapped density. The final grind moisture content was highly influenced by the initial moisture content of the corn stover grind. Optimization of the response surface models using the hybrid genetic algorithm indicated that moisture content in the range of 17 to 19% (w.b.) and a grinder speed of 47 to 49 Hz maximized the bulk and tapped density and minimized the geomantic mean particle length. The specific energy consumption was minimized when the grinder speed was about 20 Hz and the corn stover grind moisture content was about 10% (w.b.).


2021 ◽  
pp. 51-64
Author(s):  
Balasubramanian S ◽  
Raj kumar ◽  
Ram Awatar ◽  
KK Singh

Coriander (Coriandrum sativum) at three moisture content (5.7, 11.4 and 17.2 %, db) were ground using a micro pulverizer hammer mill with different grinder screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg/h) at 3000 rpm. Specific energy consumption were found decreased from 204.67 to 23.09 kJ/kg for increased levels of feed rate and grinder screen openings. The highest specific energy consumption was recorded for 17.2 % moisture content and 8 kg/h feed rate with 0.5 mm screen opening. Average particle size decreased from 0.99 to 0.47 mm with increase of moisture content and decrease in grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg/h feed rate. Bond's work index and Kick's constant were increased from 0.61 to 3.07 kWh/kg, 0.073 to 0.324 kWh/kg with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of coriander seed were found decreased from 4.92 to 2.29 and 0.002 to 1.600 with the increase of moisture content, feed rate and grinder screen opening. The loose and compact bulk densities varied from 210 to 475 kg/m3 and 231 to 550 kg/m3, respectively for various mass fractions of sieve analysis. Bond's work index and Kick's constants were affected significantly by feed rate and moisture content for all screen openings except 0.5 mm.


Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 652
Author(s):  
Tianyou Chen ◽  
Honglei Jia ◽  
Shengwei Zhang ◽  
Xumin Sun ◽  
Yuqiu Song ◽  
...  

Pressed condensation is a key process before the reclamation of loose corn straws. In this study, the effects of stabilization time on the relaxation density and dimensional stability of corn straws were studied firstly, and then the stabilization time was determined to be 60 s by comprehensively considering the compression effect, energy consumption, efficiency and significance. On this basis, the effects of the water content (12%, 15%, 18%), ratio of pressure maintenance time to stabilization time (0, 0.5, 1), maximum compression stress (60.4, 120.8, 181.2 kPa) and feeding mass (2.5, 3, 3.5 kg) on the relaxation density, dimensional stability coefficient, and specific energy consumption of post-compression straw blocks were investigated by the Box–Behnken design. It was found that the water content, ratio of pressure maintenance time to stabilization time, maximum compression stress, and feeding mass all very significantly affected the relaxation density, dimensional stability coefficient and specific energy consumption. The interaction between water content and maximum compression stress significantly affected both relaxation density and specific energy consumption. The interaction between the ratio of pressure maintenance time to stabilization time and feeding mass significantly affected the dimensional stability coefficient. The factors and the indices were regressed by quadratic equations, with the coefficients of determination larger than 0.97 in all equations. The optimized process parameters were water content of 13.63%, pressure maintenance time of 22.8 s, strain maintenance time of 37.2 s, maximum compression stress of 109.58 kPa, and raw material feeding mass of 3.5 kg. Under these conditions, the relaxation density of cold-pressed straw blocks was 145.63 kg/m3, the dimensional stability coefficient was 86.89%, and specific energy consumption was 245.78 J/kg. The errors between test results and predicted results were less than 2%. The low calorific value of cold-pressed chopped corn straw blocks was 12.8 MJ/kg. Through the situational analysis method based on the internal and external competition environments and competition conditions (SWOT analysis method), the cold-pressed chopped corn straw blocks consumed the lowest forming energy consumption than other forming methods and, thus, are feasible for heating by farmers. Our findings may provide a reference for corn straw bundling, cold-press forming processes and straw bale re-compressing.


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