Densification of agro-residues for sustainable energy generation: an overview

Abstract

The global demand for sustainable energy is increasing due to urbanization, industrialization, population, and developmental growth. Transforming the large quantities of biomass resources such as agro-residues/wastes could raise the energy supply and promote energy mix. Residues of biomass instituted in the rural and industrial centers are enormous, and poor management of these residues results in several indescribable environmental threats. The energy potential of these residues can provide job opportunities and income for nations. The generation and utilization of dissimilar biomass as feedstock for energy production via densification could advance the diversity of energy crops. An increase in renewable and clean energy demand will likely increase the request for biomass residues for renewable energy generation via densification. This will reduce the environmental challenges associated with burning and dumping of these residues in an open field. Densification is the process of compacting particles together through the application of pressure to form solid fuels. Marketable densification is usually carried out using conventional pressure-driven processes such as extrusion, screw press, piston type, hydraulic piston press, roller press, and pallet press (ring and flat die). Based on compaction, densification methods can be categorized into high-pressure, medium-pressure, and low-pressure compactions. The common densification processes are briquetting, pelletizing, bailing, and cubing. They manufacture solid fuel with desirable fuel characteristics—physical, mechanical, chemical, thermal, and combustion characteristics. Fuel briquettes and pellets have numerous advantages and applications both in domestic and industrial settings. However, for biomass to be rationally and efficiently utilized as solid fuel, it must be characterized to determine its fuel properties. Herein, an overview of the densification of biomass residues as a source of sustainable energy is presented.

A Review of Biomass Briquette Binders and Quality Parameters

“…While binders are used to improve bonding between biomass particles during densification, actual mechanism of the bonding process is complex and yet to be fully comprehended [35]. Previous studies have propagated a number of theories to explain particle bonding in biomass densification including attraction forces between biomass particles, adhesion and cohesion forces, solid bridges and mechanical interlocking bonds, interfacial forces, and capillary pressure [36][37][38]. These theories have been approached from both mechanical and chemical point of views thus explaining the influence of biomass structural and chemical substances on the bonding process during densification.…”

Production of Producer Gas from Densified Agricultural Biomass in Downdraft Gasifier and Its Application to Small Diesel Engines

“…Densification is a pre-treatment method of the raw biomass for conversion into useful energy via biomass conversion technology [3]. Moreover, the conversion of biomass to highdensity solid fuels may solve the problem of agricultural waste and high reliance on wood as a fuel source [4][5][6][7].…”

Assessment of Quality Indicators of Pressed Biofuel Produced from Coarse Herbaceous Plants and Determination of the Influence of Moisture on the Properties of Pellets

“…Biomass is an environmentally friendly energy source, which can reduce carbon emissions, and the use of biomass can be an alternative to fossil fuels, which can reduce GHG emissions. Researchers around the world are investigating and developing biomass compaction technologies, such as granulation, briquetting, and others [3,4].…”