Pyrolysis: A Theoretical and Experimental Study on the Conversion of Softwood Sawmill Residues to Biooil

Abstract

The pyrolysis of biomass is a complex process in terms of the kinetic and mass and heat transfer phenomena, which is necessary information for process optimization and large scale modeling. In this paper, an analysis of pyrolysis of sawmill residues is performed in a lab-scale pyrolysis unit to minimize the heat and mass transfer effects. Three factors, including pyrolysis temperature, feedstock particle size, and nitrogen flow rate, in the reactor are optimized using response surface methodology. Two factor-based models (a three factor quadratic model and a quadratic model without factor interactions coefficients) and two kinetic models (one based on primary reactions only, the second including secondary reactions) are compared. The factor-based models (with and without interactions) were developed using design of experiment software and Genetic Algorithm, respectively. The results showed that the quadratic model with interactions between factors predicts the experimental data more accurately compared to the other models. However, the quadratic models are experiment specific and can only be used as a design tool. The primary kinetic model predicts the experimental data trend below 550°C well; however, as temperature rises (>550°C), including secondary reactions gives better predictions.

Pyrolytic Conversion of Plastic Waste to Value-Added Products and Fuels: A Review

“…Pyrolysis is a versatile thermal cracking process that occurs in the absence of oxygen at temperatures above 400 °C. Typically, pyrolysis processes are classified as slow, fast, and flash [ 24 , 25 ]. This thermochemical process breaks down the long chain polymer molecules into smaller and less complex molecules through heat and chemical reactions.…”

“…Slow pyrolysis is typically performed at temperatures between 350 and 550 °C, with 1 to 10 °C/min heating rates, and a prolonged vapor residence time. The major product of slow pyrolysis is a solid residue, called char, as a slow heating rate favors solid formation among various parallel-competitive reactions [ 25 ]. Fast pyrolysis often takes place at temperatures between 500 and 700 °C.…”

“…Fast pyrolysis favors liquid production and, depending on the feedstock type, the liquid yield can surprisingly reach up to 90 wt.% for the pyrolysis of polyolefin materials [ 27 ]. In flash pyrolysis, the temperature is usually above 700 °C, the heating rate experienced by the feed is extremely fast, and vapor residence times are in the range of milliseconds [ 25 ]. Flash pyrolysis can produce higher yields of oil than fast pyrolysis for biomass feedstocks, while it differs for plastic waste, as the latter produces more gas compared to other products [ 28 ].…”

Soil amendments for sustainable agriculture: Microbial organic fertilizers

“…Biochar is a pyrogenic carbon derived from the pyrolysis (thermochemical conversion in the absence of oxygen) of a wide variety of biomass materials (Bamdad & Hawboldt, 2016;Bamdad et al, 2019), such as forestry, agricultural and animal residues, biosolids, and the organic fraction of municipal solid waste (Papari et al, 2015(Papari et al, , 2017. Biochar is a promising soil amendment, which can contribute to the reduction of agricultural and urban solid wastes while improving soil/plant quality.…”

Experimental investigations on sugarcane bagasse pyrolytic oil production from flash pyrolysis using a rotary screw reactor

“…The thermal cracking and hence breaking of heavier hydrocarbons accelerated as the temperature rises over 550 °C, resulting in higher gas yields and reduced char and liquid items. 42,43 Figure 5 depicts the effect of temperature on the pyrolysis stage transition. Pyrolysis produces char, gas and liquid as an end result.…”