Heating Value Of Biomass Research Articles

Mathematical Optimization of Ironmaking with Biomass as Auxiliary Reductant in the Blast Furnace

The potential of using biomass in ironmaking is investigated by simulation. Biomass is used to partially replace fossil reductants in the blast furnace process, which is described mathematically by a thermodynamic model. The model is cast in linear form to facilitate an efficient economic optimization of the production of raw steel, considering costs of raw materials, energy and CO2 emissions of the unit processes up to the basic oxygen furnace. The high oxygen content and low heating value of biomass makes it necessary to study a possible external pyrolysis of it prior to injection into the furnace. The economy of biomass injection and its dependence on the price structure of raw materials and emissions are investigated. The results throws light on how the prices of biomass and emission rights, compared to the price of coal and coke, affect the optimal biomass pre-processing (pyrolysis) and injection rate.

Prediction of heating values of biomass fuel from elemental composition

The heating value of biomass is an important parameter for the design and the control of power plants using this type of fuel. The so-called higher heating value, HHV, is the enthalpy of complete combustion of a fuel including the condensation enthalpy of formed water. Numerous empirical equations have been published to relate the heating value to the elemental composition of fuels other than biomass. Data of 154 biomass samples of very different origin (for instance wood, grass, rye, rape, reed, brewery waste, and poultry litter) have been selected from the database BIOBIB. Each sample has been characterized by the contents (in mass% of dry material) of carbon, hydrogen, nitrogen, oxygen, sulfur, chlorine and ash. PCA of these data shows a clustering according to the origin of the samples. A subset of 122 samples, all consisting of plant materials, has been used to develop regression models for a prediction of HHV from the elemental composition. Models with best predictive ability have been obtained using the contents of carbon, C; hydrogen, H; and nitrogen, N, and applying the methods OLS and PLS with the variables C, C 2, H, C × H and N. The standard errors of prediction of the best new models are considerably smaller than those obtained with models found in literature.

Energy aspects in LCA of forest products

This paper outlines guidelines for the treatment of energy in LCAs of forest products. The paper is a result of the Cost Action E 9 ‘Life cycle assessment of forestry and forest products’ and reflects the experience of Cost E9 delegates, contributing to Working Group ‘End of life — recycling, disposal and energy generation’. After overviewing different aspects of energy in LCA of forest products, the most important aspects are identified: 1) energy and carbon balance, 2) energy generation, 3) energy substitution and 4) comparison with other waste management options. For these aspects, guidelines are developed and examples are given to demonstrate the practical application of recommended guidelines. Beside the proper treatment of the above mentioned aspects, the following conclusions for the LCA practitioners are given: 1) Draw attention to losses of potential energy in carbon flows. 2) Compared to heating value of biomass the auxiliary energy need is low (<10%). 3) The substitution rate (bioenergy for fossil fuel) might be lower than 100%, depending on technical systems available. 4) A high substitution rate might be an optimisation criterion for LCA. 5) A sensitivity analysis of different substitution criteria should be made. 6) Compare energy generation to other waste management options. 7) Use of bioenergy might be ‘CO2-neutral’, but not ‘CO2-free’. 8) Most important benefit of bioenergy is greenhouse gas reduction by substituting fossil energy.

Relationships between lignin contents and heating values of biomass

The higher heating values (HHVs) of 14 biomass fuels were correlated with their lignin content. There was a highly significant linear correlation between the HHV of the biomass fuel and the lignin content. The HHV (kJ g −1) of the biomass fuel as a function of lignin content (L, wt%) was calculated using the following equations: HHV=0.0889 L +16.8218 HHV=0.0877 L +16.4951 for which the correlation coefficients ( r) were 0.9504 and 0.9302, respectively. The HHVs calculated with these equations showed mean differences of 0.056 and 0.067%, respectively.

97/02025 Heating value of biomass and biomass pyrolysis products

97/02025 Heating value of biomass and biomass pyrolysis products

97/00487 Heating value of biomass and biomass pyrolysis products

97/00487 Heating value of biomass and biomass pyrolysis products

Heating value of biomass and biomass pyrolysis products

Studies conducted on the heating value of various types of biomass components and their pyrolysis products such as char, liquids and gases are presented. Heating values of chars are comparable with those of lignite and coke; heating values of liquids are comparable with those of oxygenated fuels such as methanol and ethanol, which are much lower than those of petroleum fuels. Heating values of gases are comparable with those of producer gas or coal gas and are much lower than that of natural gas. It is also found that the heating values of products are functions of the initial composition of biomass; correlations are developed to express these. Also, correlations are developed which explain the influence of ash elements on heating values of the pyrolysis products and on percentage distribution of energy in the products.

96/05927 Studies of treatment of coking gas for hydrogen production feed and its commercial applications

Cross contamination and non-recyclables remain after the separation of valuables in the recycling process, especially with commingled or single stream recycling systems. Therefore, some carbonaceous fractions of recyclables, such as plastics and fibers, are left as a potential biomass feedstock for the thermochemical or thermal conversion processes. However, this fraction of waste is more likely to be highly contaminated and challenging, or may become unpredictable during its reuse in the thermal conversion process for heat and power applications. The current study aims to find how the increase in plastic specifically in the recycled fiber stream may affect the performance of a downdraft gasifier. Therefore, the effect of plastic combined with fiber feedstock during gasification has been investigated. For this purpose, three different plastic percentages of 2%, 5%, and 10% mixed with fiber were studied. The results showed that higher plastic-containing feedstock has higher energy content; however, the higher plastic content causes mechanical performance issues inside the reactor and does not necessarily guarantee greater biomass heating value. Furthermore, gasifying the higher plastic percentage results in a temperature drop across the reactor. This change in temperature is the result of thermal reactions of fiber material mixed with plastic that generates firm clinkers and interrupts the normal conditions in the reactor. The clinker predominantly contains aluminum, silicon, calcium and sodium that originate from the source of fiber and plastic. This research has shown that a mixture of silicon with aluminum, calcium and sodium under high temperatures result in the generation of a solid clinker that ultimately moves through the reactor and deposits at the bottom of the reactor.