Pyrolytic Conversion of Biomass Residues to Gaseous Fuels for Electricity Generation

Abstract

As petroleum resources are finite, it is imperative to use them wisely in energy conversion applications and, at the same time, develop alternative energy sources. Biomass is one of the renewable energy sources that can he used to partially replace fossil fuels. Biomasshased fuels can be produced domestically and can reduce dependency on fuel imports. Due to their abundant supply, and given that to an appreciable extent they can be considered carbon-neutral, their use for power generation is of technological interest. However, whereas biomasses can be directly burned in furnaces, such a conventional direct combustion technique is ill-controlled and typically produces considerable amounts of health-hazardous airborne compounds. Thus, an alternative technology for biomass utilization is described herein to address increasing energy needs in an environmentallybenign manner. More specifically, a multistep process/device is presented to accept granulated or pelietized biomass, and generate an easily-identifiable form of energy as a final product. To achieve low emissions of products of incomplete combustion, the biomass is gasified pyrolytically, mixed with air, ignited and, finally, burned in nominally premixed low-emission fiâmes. Combustion is thus indirect, since the biomass is not directly burned, instead its gaseous pyrolyzates are burned upon mixing with air. Thereby, combustion is well-controlled and can be complete. A demonstration device has been constructed to convert the internal energy of biomass into "clean" thermal energy and, eventually to electricity.

Combustion of single biomass particles in air and in oxy-fuel conditions

“…Biomass structures, and heavy hydrocarbons and tars, produced by the devolatilization step have been reported to expediently convert into smaller molecules by cracking reactions in the proximity of the devolatilizing particles [49]. In fact, previous work in this laboratory [50,51,52,53] The proximate and ultimate analyses of the different biomasses were similar, see Table 1, and so was their combustion behavior. The sugarcane bagasse, SCB, has the highest volatile matter content, therefore extra time was likely needed for devolatilization, and the combustion duration of the volatiles of this fuel was indeed observed to be lengthier (see Fig.…”

Harnessing the potential of bio‐ethanol production from lignocellulosic biomass in Nigeria – a review

“…The use of corn cobs to produce bioethanol comes with some challenges and to surmount these challenges, some factors, including but not limited to the mode of harvesting, crop handling, storage/preservation methods and conversion methods, should be developed further . The heating value of corncob is about 19.14 MJ kg −1 , it can therefore be used as a potential thermo‐chemical feedstock . The large quantities of corn cobs generated annually make it a perfect potential feedstock for bioethanol production.…”

“…30 The heating value of corncob is about 19.14 MJ kg −1 , it can therefore be used as a potential thermo-chemical feedstock. 31 The large quantities of corn cobs generated annually make it a perfect potential feedstock for bioethanol production. Table 3 shows the proximate composition of corn cob.…”

A Comprehensive Investigation on the Effects of Biomass Particle Size in Cellulosic Biofuel Production

“…The composition of cellulosic biomass varies by species. The three main components are cellulose (40-50%), hemicellulose (20-30%), and lignin (15-20%) [11,12]. Surrounding cellulose fibrils (an agglomeration of glucan chains with a large number of glucose units) are hemicellulose and lignin that interweave to form the networking structure as shown in Fig.…”

“…Lignin is a large group of aromatic polymers and contains no sugar components. Lignin can be used to make value-added chemicals and biobased products or burned to produce bioenergy [11][12][13]. Figure 2 illustrates the major steps of converting cellulosic biomass feedstocks into biofuels.…”