Approximation to distributed activation energy model for residual logging of cedrus deodora using weibull distribution

The paper focuses to explain the influence of some relevant parameters of biomass pyrolysis on the numerical solution of isothermal n th order distributed activation energy model (DAEM). The upper limit of “dE”, the frequency factors, the reaction order, the shape and location parameters of the Weibull distribution are studied. These parameters have been used for estimating the kinetic parameters of the isothermal Weibull DAEM from thermo analytical data of loose biomass. Moreover, asymptotic approach has been adopted to find the solution of DAEM.Authors wish to acknowledge the support of Department of Mathematics, Statistics and Computer Science of Govind Ballabh Pant University of Agriculture and Technology (GBPUA&T) for assisting in their work. They also express their sincere gratitude to IIC, IIT Roorkee and SAIF, IIT Bombay for their help in conducting the experiments on Cedrus Deodara leaves.Publisher's Versio

Construction of a Packed-Bed Pyrolysis Reactor For Charcoal Production

The paper pivoted on processing forest waste, Austrian Pine, for producing carbon enriched char. A small-packed bed reactor was developed to pyrolysis the processed char. The preparation of feedstock was carried out in an improvised muffle furnace. The following parameters were obtained to determine the potential of pine waste: thermal effectiveness, oil yield, char yield, gas yield, specific biomass consumption, and carbon conversion efficiency of the unit. The absolute increase in the cold gas efficiency of pine needles after torrefaction was 44%. As compared to Acacia wood chips (G30 and G50), a 4.8% rise in the carbon conversion efficiency was seen after thermal pre-treatment of pine needles. However, it was relatively dropped by 2% to the wood pellets. The obtained char yield from torrefied pine needles as to the wood pellets was augmented by 160%. On the contrary, the oil yield derived from torrefied pine pellet was dropped by 65% while comparing it with the wood pellets. The carbon dioxide emission was mitigated by 3.4% after torrefaction of raw pine needles, whereas it was reduced by 11.71% when it was compared with commercial wood pellets. A pronounced rise of 123% in the clean gas production was noticed after the torrefaction of pine needles, while it was 14.96% when it was compared with the wood pellets

Thermo-kinetics of Forest Waste Using Model-Free Methods

Thermal behaviour of pine needles (Pinus Roxburghii) is examined through a thermogravimetry technique. The dried samples of pine needles undergo the non-isothermal decomposition at temperature range of 308-1173 K. The heating rates used for experimental purposes are: 5 ◦C min−1 , 10 ◦C min−1 and 15 ◦C min−1 . Kinetic parameters of thermal decomposition reactions of pine needles are obtained through the model-free schemes. The estimated values of activation energy and frequency factor derived from Kissinger method are 132.77 kJ mol−1 and 13.15 × 107 min−1 , respectively. Furthermore, the averaged values of the same kinetics parameters retrieved from the isoconversional methods are 82.38 kJ mol−1 and 74.833 kJ mol−1 , 25.42 × 1013 min−1 and 13.449 × 1010 min−1 , respectively. Instead of the Flynn-Wall- Ozawa (FWO) and Kissinger- Akahira- Sunrose (KAS) schemes, the kinetic parameters derived from the Kissinger method are relatively promising for the thermal decomposition process, since the kinetic parameters are highly affected by intermediate stages and overlapping of the concurrent reaction occurred during pyrolysis

Developing a Grey Forecasting Model for the Air Flowing across the Parallel Plate Duct

The focus of this work is on developing a nonlinear grey model for the laminar flow regime of carrier fluid across the flat plate collector. The trust region reflective algorithm was used to solve the nonlinear laminar flow problem and handle the sparse matrix. The stream function, dimensionless velocity, gradients of velocity components, carrier fluid temperature, and the absorber plate temperature were estimated for a flat plate collector operated with and without a circular chimney. Similarly, the same technique was adopted to determine a model for heat transfer across the absorber plate. The numerically obtained solution was also compared with the parameters obtained through the instrumental measurement. The relative tolerance was kept at 10−5 for the white and grey box solutions. The developed model was noticed to have a smaller deviation than the conventional analytical model to predict the experimental values. The slip condition was observed for the proposed scheme. The uncertainty in the temperature measurement through the proposed model varies from ±0.53 to ±1.47 K. The minimum absolute percentage error (MAPE) lies in the domain of 0.52–1.67% for the nonlinear grey model, whereas the linear grey model for measuring absorber plate temperature has a percentage error of 0.0011–0.02%

Effect of Ambient Parameters on the Temperature Distribution of Photovoltaic (PV) Modules

This paper pivots around the influence of thermal parameters on the temperature distribution of a (PV) module. The solar irradiance, ambient temperature, and heat transfer coefficient were examined for four differently manufactured solar modules. A finite element analysis of the solar system was carried out to simulate the prevailing thermal conditions. It was determined through analysis that the heat transfer coefficient had a significant effect on the boundaries of the PV modules. The temperature gradient was relatively high at the boundary, whereas the main body had the least deviation from the mean value of experimental data. The high value of irradiance is favorable for a large PV system, while the heat transfer coefficient should be low for avoiding undulation of the thermal gradient across the plate. The temperature distribution on the surface of the PV modules largely depended on the geometry and the material used for the design purpose

Asymptotic Approximations to the Isothermal Pyrolysis of Deodara Leaves using Gamma Distribution

The main aim of this paper pivoted around the influence of some parameters relevant to biomass pyrolysis on the numerical solutions of the n th order distributed activation energy model (DAEM) using the Gamma distribution. The upper limit of ‘dE’ integral, frequency factor, reaction order, and the shape and rate parameters of the Gamma distribution are investigated. Analysis of the mathematical model is done with the help of asymptotic expansion

Kinetics of the thermal decomposition of pine needles

A kinetic study of the pyrolysis process of pine needles was examined using a thermogravimetric analyser. The weight loss was measured in nitrogen atmosphere at a purge flow rate of 100 ml/min. The samples were heated over a range of temperature of 19°C–600°C with a heating rate of 10°C/min. The results obtained from the thermal decomposition process indicate that there are three main stages: dehydration, active and passive pyrolysis. The kinetic parameters for the different samples, such as activation energy and pre-exponential factor, are obtained by the shrinking core model (reaction-controlled regime), the model-free, and the first-order model. Experimental results showed that the shrinking model is in good agreement and can be successfully used to understand degradation mechanism of loose biomass. The result obtained from the reaction-controlled regime represented actual values of kinetic parameters which are the same for the whole pyrolysis process; whereas the model-free method presented apparent values of kinetic parameters, as they are dependent on the unknown function ϕ(C), on the sum of the parameters of the physical processes, and on the chemical reactions that happen simultaneously during pyrolysis. Experimental results showed that values of kinetic constant from the first-order model and the SCM are in good agreement and can be successfully used to understand the behaviour of loose biomass (pine needles) in the presence of inert atmosphere. Using TGA results, the simulating pyrolysis can be done, with the help of computer software, to achieve a comprehensive detail of the devolatilization process of different types of biomasses

Optimisation of the performance of a pyrolysis reactor for G50 chips

The aim of any industrial plant, which is dealing in the energy sector, is to maximise the revenue generation at the lowest production cost. It can be carried out either by optimizing the manpower or by improving the performance index of the overall unit. This paper focuses on the optimisation of a biomass power plant which is powered by G50 hardwood chips (Austrian standard for biomass chips). The experiments are conducted at different operating conditions. The overall effect of the enhanced abilities of a reactor on the power generation is examined. The output enthalpy of a generated gas, the gas yield of a reactor and the driving mechanism of the pyrolysis are examined in this analysis. The thermal efficiency of the plant is found to vary from 44 to 47% at 400°C, whereas it is 44 to 48% for running the same unit at 600°C. The transient thermal condition is solved with the help of the lumped capacitance method. The thermal efficiency of the same design, within the constraint limit, is enhanced by 5.5%, whereas the enthalpy of the produced gas is magnified by 49.49% through nonlinear optimisation. The temperature of biomass should be homogenous, and the ramping rate must be very high. The 16% rise in temperature of the reactor is required to reduce the mass yield by 20.17%. The gas yield of the reactor is increased by up to 85%. The thermal assessment indicates that the bed is thermally thin, thus the exterior heat transfer rate is a deciding factor of the pyrolysis in the reactor

Stochastic Analysis of Multi-Reaction Model for Non-Linear Thermal History

This paper investigates the effect of non-linear thermal profile on the numerical solution of the multi-reaction model. According to the practical perspective, the temperature distribution at a different section of pyrolysis reactor is not necessarily following the ideal thermal history; therefore, it is necessary to predict the behaviour of the system for the higher degree of freedom. TG thermogram is obtained by the thermal degradation of pine needles sample in the thermogravimetric analyser (TGA). The activation energy, frequency factor, reaction order and the scale, shape and location parameters of a stochastic function are estimated for the non-linear parabolic thermal profile. The conventional Laplace integral is used to approximate the multi-reaction model. Activation energy obtained for the non-thermal profile lies in the range of 57.5–60 kJ·mol−1, whereas the frequency factor varies from 103–105 min-1. The obtained value of reaction order (n) lies in the domain of (0.9, 1.6)