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Additives in Bio-Oil Components for Increased Stability, Quality, and Legal Status

Abhinav Koushik1, Jayendra Kasture2* and Milind Shrinivas Dangate1†

1Chemistry Division, School of Advanced Sciences, Vellore Institute of Technology, Chennai, Tamil Nadu, India

2VIT School of Law, Vellore Institute of Technology, Chennai, India

Abstract

Malaysia, one of the biggest producers of palm oil worldwide, faced a significant disposal issue due to the enormous amount of oil palm biomass wastes generated. Fast pyrolysis technology can be used to liquefy these biomass wastes into biofuel in order to solve this issue. To get rid of its unwanted qualities, fast pyrolysis bio-oil has to be upgraded further via direct solvent addition. To establish competitiveness with regular diesel fuel, the envisioned blend of solvent and oil must align with benchmarks for both fuel efficiency and cost-effectiveness. Chemical signature descriptors were harnessed to correlate predictions across multiple classes of properties within the design challenge. Nonetheless, the intricacy inherent in the computer-aided molecular design (CAMD) challenge escalates as the length of the signature expands, owing as made to introduce a consistency rule, aimed at diminishing the scale and complexity of the CAMD undertaking. Then, to expand the CAMD problem to incorporate the economic components, a fuzzy optimization with multiple objectives approach was applied. Then, a rough set–based artificial intelligence model has been constructed to connect the feedstock description and pyro condition with the decomposition bio-oil properties. The generated decisions were carefully investigated in order to identify the deeper trends and to confirm that the created choice rules made sense. To manufacture pyrolysis bio-oil with desired fuel qualities, the best feedstock composition and pyrolysis conditions can be chosen using the decision rules developed. Next, experimental research was used to confirm the conclusions of the computational methodologies. To sum up, this chapter discussed how to improve the fuel qualities of pyrolysis bio-oil using a combination of computational and experimental methods.

Keywords: Palm oil, bio-oil, pyrolysis, emulsification, additives

1.1 Introduction

During the past century, burning fossil fuels has produced practically all of the energy needed for daily life. As of this writing, fossil fuels still meet roughly 80% of the global daily energy needs [1]. According to reports, 98.8 million kilograms of liquid gasoline and petroleum were utilized each day in the world in July 2022. It was anticipated that, by 2023, this amount will increase even further, averaging 101.5 million barrels of oil per day [2]. For the thermochemical conversion of palm biomass, a wide range of bio-fuels could be created through methods like liquefaction, gasification, and pyrolysis. The advantage of the pyrolysis process over other biomass conversion technologies is that it can produce bio-oil, charcoal, and gaseous byproducts as a result of the conversion of solid palm biomass feedstock. On the contrary, pyrolysis bio-oil presents an intricate mixture primarily consisting. According to a study by Khosravanipour Mostafazadeh et al. [3], efforts to directly utilize pyrolysis bio-oil in gas turbines or diesel engines have encountered difficulties due to its limited compatibility with traditional petroleum fuels. To overcome these challenges, various techniques for upgrading pyrolysis bio-oil have been proposed and explored, involving both physical and chemical approaches of the bio-oil produced through pyrolysis can be enhanced by incorporating solvents [3].

1.2 Background Problems

For oil and solvents, earlier research primarily focused on mechanically blending decomposition bio-oil with various solvents, selected based on their general characteristics. The conventional approach to selecting and pinpointing solvents typically involved a time-consuming experimental process of trial and error from a wide array of possibilities. This exhaustive testing of all potential solvents could be impractical, leading to an extended timeframe for assessment [4] frequently employed to develop viable solvent options that fulfill specific property criteria and constraints [5]. Computer-aided molecular design (CAMD), built around predetermined target properties, operates as a method of reverse engineering, predicting and approximating suitable molecules while assembling them from a set of molecular building blocks. Previous endeavors have been undertaken to create solvents appropriate for bio-oil applications using the CAMD approach.

1.3 Pyrolysis Bio-Oil

When pyrolysis process happens, biomass source material is thermally broken to produce syngas, biochar, and bio-oil. The pyrolysis process is akin to the well-known way of creating coal [6]. Operational variables including humidity, vapor residency time, heating, and feedstock have an impact on how pyrolysis products are distributed at the end. The pyrolysis product’s ultimate composition is most strongly influenced by temperature, though. On the other hand, the faster heating and higher temperature (400°C to 500°C) stimulate the creation of levoglucosan, the catalyst for the development of the substance that causes smaller molecules to form, giving rise to liquid products. A few examples of the gaseous products produced by the decomposition of biomass at temperatures exceeding 650°C are carbon monoxide, hydrogen, and methane [7]. The three types of pyrolysis reactions—slow, rapid, and fast pyrolysis—can be classified depending on the operating parameters.

1.3.1 Fast Pyrolysis

Fast pyrolysis is a process that swiftly elevates the temperature of biomass to a high degree while impeding the ingress of oxygen. However, it is important to note that fast pyrolysis does not achieve the same rapid temperature increase as flash pyrolysis. According to findings by [8], the output of high-quality bio-oil is typically associated with fast pyrolysis. For instance, in the temperature range of 400°C to 700°C, swift pyrolysis of teak sawdust led to notable results. At 600°C, a peak bio-oil production of 48.8 was achieved [9]. Furthermore, a maximum yield of 44.16 weight percent of bio-oil from wood sawdust pyrolysis was attained through pre-treatment of empty fruit bunches using diluted nitric acid [9]. Additional advancements have been observed by employing diluted nitric acid through acid washing in order to enhance liquid output.

In a separate study by Solikhah et al. [10], the quick pyrolysis technique was employed to generate pyrolysis bio-oil using oil palm fronds and empty fruit bunches from palm oil.

Bio-oils from empty fruit bunches and oil palm fronds were shown to have higher heating values, with respective values of 12.19 MJ/kg and 26.49 MJ/kg. To quickly pyrolyze biomass for bio-oil, a variety of reactor configurations are suitable [11]. These configurations include fluidized bed, entrained flow, wire mesh, vacuum furnace, vortex, and rotating and circulating fluidized bed reactors. The fluidized bed reactor is the most promising of the aforementioned reactors for fast pyrolysis because it provides for high heating rates, quick de-volatilization, simple control, and inexpensive costs.

1.3.2 Chemical Improvement of Bio-Oil From Pyrolysis

Prior to gasification with synthesis gas, pyrolysis can function as a thermal pre-treatment, as pointed out [7]. The modest energy penalties such as reduced energy effectiveness of pyrolysis, increased transportation energy, and the need for an additional step of bio-oil gasification, as outlined, can be viewed in the context of this process.

1.4 Using the Characterization and Pyrolysis Conditions of the Biomass Feedstock, One May the Qualities of the Bio-Oil Produced by Fast Pyrolysis

A driven by information rough set–based machine learning (ML) model was suggested for the final subregion in order to estimate pyrolysis biological oil qualities based on the temperature of pyrolysis and feedstock parameters. On the basis of peer-reviewed studies and experiments, a database containing preliminary and thorough evaluations of the wood substance, pyrolysis the temperature, the pH value of the bio-oil, and the hydrophilic strength of the bio-oil is initially created. A research scientific study is carried out to identify fundamental trends or patterns in order to check that the generated rules of decision-making make sense and work for potential usage. Depending on the mechanical validity and distinctive viewpoints of the choice rules, the best models of prediction and choices are selected.

1.4.1 CMD Stands for Computer-Aided Molecular Design

In previous instances, the design of solvents has often relied on heuristic rule-based or experimental approaches, resulting in the development of product designs that are reliable and safe, as highlighted by [12]. However, these conventional methodologies for solvent design have exhibited drawbacks such as being laborious, costly, and time-intensive. Moreover, it is practically infeasible to exhaustively explore all potential options or identify the optimal solution can replace the conventional trial-and-error method. CAMD stands as a viable substitute for the conventional trial-and-error technique, offering a model-based design process...