Reactivity during bench-scale combustion of biomass fuels for carbon capture and storage applications

Reactivities of four biomass samples were investigated in four combustion atmospheres using non-isothermal thermogravimetric analysis (TGA) under two heating rates. The chosen combustion atmospheres reflect carbon capture and storage (CCS) applications and include O2O2 and CO2CO2-enrichment. Application of the Coats–Redfern method assessed changes in reactivity. Reactivity varied due to heating rate: the reactivity of char oxidation was lower at higher heating rates while devolatilisation reactions were less affected. In general, and particularly at the higher heating rate, increasing [O2O2] increased combustion reactivity. A lesser effect was observed when substituting N2N2 for CO2CO2 as the comburent; in unenriched conditions this tended to reduce char oxidation reactivity while in O2O2-enriched conditions the reactivity marginally increased. Combustion in a typical, dry oxyfuel environment (30% O2O2, 70% CO2CO2) was more reactive than in air in TGA experiments. These biomass results should interest researchers seeking to understand phenomena occurring in larger scale CCS-relevant experiments

NEURAL COMPUTING & APPLICATIONS

In this paper, we consider a system of nonlinear delay integro-differential equations with convolution kernels, which arises in biology. This problem characterizes the population dynamics for two separate species. We present an exponential approach based on exponential polynomials for solving this system. This technique reduces the model problem to a matrix equation, which corresponds to a system of nonlinear algebraic equations. Also, illustrative examples related to biological species living together are given to demonstrate the validity and applicability of technique. The comparisons are made with the existing results

APPLIED MATHEMATICAL MODELLING

In this paper, a new matrix method based on exponential polynomials and collocation points is proposed for solutions of pantograph equations with linear functional arguments under the mixed conditions. Also, an error analysis technique based on residual function is developed for the suggested method. Some examples are given to demonstrate the validity and applicability of the method and the comparisons are made with existing results. (C) 2013 Elsevier Inc. All rights reserved

MATHEMATICAL METHODS IN THE APPLIED SCIENCES

In this study, a practical matrix method based on Laguerre polynomials is presented to solve the higher-order linear delay differential equations with constant coefficients and functional delays under the mixed conditions. Also, an error analysis technique based on residual function is developed and applied to some problems to demonstrate the validity and applicability of the method. In addition, an algorithm written in Matlab is given for the method. Copyright (c) 2013 John Wiley & Sons, Ltd

MATHEMATICAL AND COMPUTER MODELLING

In this study, the modified Bessel collocation method is presented to obtain the approximate solutions of the linear Lane-Emden differential equations. The method is based on the improvement of the Bessel polynomial solutions with the aid of the residual error function. First, the Bessel collocation method is applied to the linear Lane-Emden differential equations and thus the Bessel polynomial solutions are obtained. Second, an error problem is constructed by means of the residual error function and this error problem is solved by using the Bessel collocation method. By summing the Bessel polynomial solutions of the original problem and the error problem, we have the improved Bessel polynomial solutions. When the exact solution of the problem is not known, the absolute errors can be approximately computed by the Bessel polynomial solution of the error problem. In addition, examples that illustrate the pertinent features of the method are presented, and the results of this investigation are discussed. (C) 2012 Elsevier Ltd. All rights reserved

OPEN PHYSICS

Functional differential equations have importance in many areas of science such as mathematical physics. These systems are difficult to solve analytically. In this paper we consider the systems of linear functional differential equations [1-9] including the term y(alpha x + beta) and advance-delay in derivatives of y. To obtain the approximate solutions of those systems, we present a matrix-collocation method by using Muntz-Legendre polynomials and the collocation points. For this purpose, to obtain the approximate solutions of those systems, we present a matrix-collocation method by using Muntz-Legendre polynomials and the collocation points. This method transform the problem into a system of linear algebraic equations. The solutions of last system determine unknown co-efficients of original problem. Also, an error estimation technique is presented and the approximate solutions are improved by using it. The program of method is written in Matlab and the approximate solutions can be obtained easily. Also some examples are given to illustrate the validity of the method

APPLIED MATHEMATICAL MODELLING

In this paper, a Legendre collocation method based on the residual correction technique is proposed to solve the multi-pantograph and generalized pantograph equations with initial conditions. By using the residual function of the operator equation, an error differential equation is constructed and thus the approximate solution obtained by Legendre collocation method is corrected. Also, we give an upper bound of the absolute errors for the corrected shifted Legendre solution. Finally, we illustrate the method by solving the problems with initial conditions. The obtained results are compared by the known results; the error estimation and the upper bounds of the absolute errors are performed for the approximate solutions in examples. (C) 2015 Elsevier Inc. All rights reserved