Renewable Energy for Sustainable Growth Assessment. Группа авторов

Renewable Energy for Sustainable Growth Assessment - Группа авторов


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       ii. Biochemical conversions:This route helps in converting biomass to the main carbohydrate so that further, it can be converted to several bio-products like biogas and mainly liquid fuels. The agents involved are mainly bacteria and enzymes [87]. Important available technologies are fermentation and anaerobic digestion [81, 88–95].

       iii. Physico-chemical conversions:The exact conversion of biomass into bio-oil is dependent on several variables or elements, i.e., composition of feedstock, temperature and heating value, pressure, solvent, residence time, and catalysts. The process mainly involves the conversion of vegetable oil and animal fat into biodiesel. Major oils used are rapeseed, jatropha, sunflower [96, 97]. Comparison of bio-fuel (bio-diesel and bio-ethanol) production for different countries over the period 1990-2019 is shown in Figure 1.5 [98].

Schematic illustration of the thermochemical options for the production of fuels, chemicals, and power. Graph depicts the trend of bio-fuel production for different countries over the period 1990-2019.

      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].

      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

      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.


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