of the thermochemical options for the production of fuels, chemicals, and power."/>
Figure 1.4 Thermochemical options for the production of fuels, chemicals, and power [79].
Figure 1.5 Trend of bio-fuel production for different countries over the period 1990-2019 [98].
1.4 Progress in Scientific Study
The major countries that are involved in the scientific study and production of biomass, in increasing order of their intensity, are the United States, China, India, Germany and Italy. Recent progress has been identified in the areas of the use of combustion technology and the development of hybrid systems.
1.4.1 Combustion Technology
Combustion technology is constantly getting advanced, and the main thrust areas are flameless combustion, also known as Flameless Oxidation (FLOX) [99, 100], High-Temperature Air Combustion (HTAC) [101], Moderate or Intense Low Oxygen Dilution Combustion (MILD) [102] and Colorless Combustion [103]. There are several advantages while using flameless combustion. Some of them are reduction in fuel consumption, reduction in major pollutant emissions like NOx and the involvement of stable and efficient combustion. Also, it helps in higher heat transfer rate and reduction in noise often found in combustion [104–106]. Side by side interest in biomass, i.e., mainly willow and poplar, demolition wood, sawdust and bark, has increased over the years [105, 107]. The combustion of biomass includes a chain of reactions where carbon gets converted to carbon dioxide and water, whereas its incomplete combustion will lead to many harmful products like CO [108]. The main criterion for flameless combustion is to raise the temperature to the desired level [109].
The properties of biomass can be classified as microscopic (mineral data, kinetics & thermal characteristics) and macroscopic (ultimate analysis, size of the particle, moisture content, fusion temperature of ash and bulk density) [110]. The phenomenon of flameless combustion has a significant effect on the reduction of emission and combustion performance [111]. In research work, Suda et al. [112] studied emissions and combustion characteristics of coal under high-temperature conditions in a cylindrical furnace and fed by bituminous and anthracite variety of coal. By the use of the latest NOx burner technology with the staging of air, it was found to perform better mitigation of NOx [113]. The latest in flameless biomass combustion included the study on NOx formation by Roman et al. [114], and it was found that NOx emission is proportional to the concentration of oxygen in the air and the atmospheric air temperature.
It was found by [115] that with the increase in temperature, the heat transfer rate is bound to increase and that greatly increases the combustion of wood pellet. It was also found that the mass-loss rate is higher at 1000 °C than at 1100 °C. The ash and the content of moisture are the main causes of various ignition and problems of combustion [116]. Other studies were also reported in relation to flameless combustion by the release of volatile matter and suppression of ignition delay [117].
1.4.2 Hybrid Systems
In order to get a better approach towards generations based on renewables, a system approach is often preferred, and it considers the control of generators locally and its association with the subsystem known as micro-grid [118]. At the time of disturbances, the loads are separated from the system of distribution, and the micro-grid gets isolated without interfering with the integrity of the transmission grid [119]. The source of renewable energy has seasonal and daily variations. Therefore, because of its intermittent nature, it is difficult to get a continuous power flow. The techno-economic concepts for this have been discussed for remote areas [120], and the case study of the feasibility of installation of the wind farm has been studied for Australia [121]. The comparisons between computational models for hybrid systems are presented in McGowan et al. [122]. Converters of wind energy and diesel generators were predicted for reliability and economic analysis by the use of Monte Carlo techniques [123]. Different hybrid systems of solar PV/diesel were revisited by Wichert et al. [124] and highlighted future developments. The performance of different hybrid systems is also presented by Elhadidy et al. [125], and its storage in a battery is discussed by Saheb-Koussa et al. [126]. A new method for optimization of hybrid wind and solar PV and diesel system has been introduced in Belfkira et al. [127]. Similarly, different combinations of PV diesel/battery hybrid system are provided in [128–137]. Another work included biomass, solar and wind hybrid model in which HRES of biomass 20 kW, generation of wind 125 kVA and 20 kW of solar PV and further analyses on it were done for rural electrification [118].
1.4.3 Circular Bio-Economy
Nonetheless, the expense identified with the biomass assortment, isolation, transportation, and capacity is as yet a worry. The idea of using biomass as a wellspring of an environmentally friendly power and other financially significant items is a lot of coverage with the idea of circular economy, and this convergence of circular economy and bio-economy can be named as the circular bio-economy. Yet, with change in the biomass executives’ framework and shaping laws empowering the re-usage of created squander, the idea of a circular bio-economy can be carried out to address the issues of environmental change, ecological contamination, and non-renewable energy source consumption. Comparative assessment of massive scope projects is essential to distinguish the best accessible innovation for biofuel creation. Moreover, the current maintainability issues of the biomass store network ought to be routed to guarantee lasting through the year conveyance of feedstock to the transformation office. A vigorous plan of action would pull in financial backers and speed up the commercialization of biomass-inferred bio-fuel.
1.4.4 Other Notable Developments
The work conducted by Huang et al. [138] proposed a system comprising of marine fuel cell based on marine sediment and its allied systems. It was found to exploit the substrates that are biodegradable in nature and produce electricity from them. A biomass energy harvesting system has been reported for underwater applications, both experimentally and numerically [139]. In another application, biomass-derived carbon has been shown to have applications in batteries and supercapacitors [140]. In one of the extensive reviews conducted by [141], it was concluded that advanced oxidation processes had a lot of potential in the pretreatment of lignocellulosic biomass for the production of bioenergy.
1.5 Status of Biomass Utilization in India
The Ministry of New and Renewable Energy (MNRE) is providing government subsidies on gasification of biomass and cogeneration [142, 143]. India is primarily agricultural land and can provide one of the largest amounts of biomass for energy generation [144]. There are two types of residue; the primary is what one gets on the field, whereas the second is those which are obtained when it is stacked for processing [145]. Besides agriculture, cattle and livestock also contribute to a major extension to the high availability of biomass [146]. Several crops like sugarcane, pulses, corns, etc., are considered as biomass on the basis of moisture content, ash content, calorific value and carbon proportion [147, 148]. Nowadays, more focus is on bamboo, kadam, Julie flora and babul as they provide a high amount of dry content of material [149]. As per MNRE, more than 200 million tonnes of biomass are generated, and most of them are left unused or not used properly [150, 151]. Some of these wastes, in particular municipal solid waste, can be converted to energy fuels through several thermal and chemical conversion processes; otherwise, it may create a lot of problems to the drainage line as well as the underground water level [152, 153]. The wastes like fruit and
