Torrefaction is a mild pyrolysis, which has been explored for the pretreatment of biomass to increase the heating value and hydrophobicity. Due to its potential applications for making torrefied pellets, which can be used as a high quality feedstock in gasification for high quality syngas production and as a substitute for coal in thermal power plants and metallurgical processes, torrefaction and densification have attracted great interest in recent years from both academia and bioenergy industry. This paper provides a comprehensive review of research progresses in this area, drawing on major contributions from two major research groups of the authors on torrefaction and densification at Canada and Taiwan as well as literatures. It is revealed that torrefaction of various biomass species and their major components, lignin, cellulose and hemicelluloses have been extensively studied in thermogravimetric apparatus (TGA) under both inert (N 2 ) and oxidative (O 2 , H 2 O) environments to elucidate the weight loss as a function of temperature, particle size and time. It was found that the higher heating value and saturated water uptake of torrefied biomass were a strong function of weight loss, which represents the degree of torrefaction. When torrefied sawdust is compressed into torrefied pellets, more mechanical energy is consumed and higher die temperature is required to make torrefied pellets of similar density and hardness as regular pellets. Simple economics analyses based on laboratory scale experimental data showed that because of the potential savings from pellets transport, handling and storage logistics, the overall cost for torrefied pellets can be lower than regular pellets in European market for both European and Canadian pellets. The gasification could be improved in terms of both energy efficiency and syngas quality because of the removal of oxygenated volatile compounds from torrefied biomass.

A state-of-the-art review of biomass torrefaction, densification and applications

Polyurethanes (PUs) are a class of versatile materials with great potential for use in different applications, especially based on their structure–property relationships. Their specific mechanical, physical, biological, and chemical properties are attracting significant research attention to tailoring PUs for use in different applications. Enhancement of the properties and performance of PU-based materials may be achieved through changes to the production process or the raw materials used in their fabrication or via the use of advanced characterization techniques. Clearly, modification of the raw materials and production process through proper methods can produce PUs that are suitable for varied specific applications. The present study aims to shed light on the chemistry, types, and synthesis of different kinds of PUs. Some of the important research studies relating to PUs, including their synthesis method, characterization techniques, and research findings, are comprehensively discussed. Herein, recent advances in new types of PUs and their synthesis for various applications are also presented. Furthermore, information is provided on the environmental friendliness of the PUs, with a specific emphasis on their recyclability and recoverability.

https://ir.unikl.edu.my/jspui/bitstream/123456789/15237/1/Polyurethane%20types%2c%20synthesis%20and%20applications%20%e2%80%93%20a%20review.pdf

Polyurethane types, synthesis and applications – a review

Recent development in the treatment of oily sludge from petroleum industry: A review

A review on thermal and catalytic pyrolysis of plastic solid waste (PSW)

Thermal degradation of PVC: A review.

On the thermal treatment of plastic mixtures of MSW: Pyrolysis kinetics

Oil sludge, if unused, is one of the major industrial wastes that needs to be treated for the refinery or petrochemical industry. It contains a large portion of combustible components with high heating values. Obviously, the conversion of oil sludge to various useful materials such as lower molecular weight organic compounds and carbonaceous residue via pyrolysis not only solves the disposal problem but also matches the appeal of resource utilization. In this study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in northern Taiwan is used as the raw material of pyrolysis. Its heating value of dry basis and low heating value of wet basis are about 10681 and 5870 kcal/kg, respectively. The pyrolysis of oil sludge is conducted by using nitrogen as carrier gas in the temperature range 378−873 K. The pyrolytic reaction is complex and significant in the range 450−800 K. The residues of pyrolysis of oil sludge exhibit very high viscous form below 623 K (pyrolysis temperatu...

Major Products Obtained from the Pyrolysis of Oil Sludge

Previous efforts were made to convert the oil sludge into useful resources such as lower molecule organic compounds and carbonaceous residues by pyrolysis with the carrier gas of N2. In the present study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in the northern Taiwan was used as the raw material of pyrolysis. The influences of using sodium and potassium compounds as additives on the possible improvement of the pyrolysis of oil sludge are investigated. The additives employed include two groups: (1) sodium compounds (NaOH, NaCl and Na2CO3), and (2) potassium compounds (KCl, KOH and K2CO3). For the increases of conversion, the additives provide the offers in the order of K2CO3>KOH>NaOH>Na2CO3>KCl>NaCl>no additives. It appears that the above additives enhance the reaction rates when the temperatures are in 650–710 K, following the orders NaOH>Na2CO3>NaCl>no additives, and K2CO3>KOH>KCl>no additives. The additives achieve the improvement of the quality of pyrolysis oil (as sum of light and heavy naphtha and light gas oil) in the order of KOH>KCl>K2CO3>NaOH>Na2CO3>NaCl>no additives. Nevertheless, the additives improve the liquid yields in the order of KCl>Na2CO3>NaCl>no additives>NaOH>K2CO3>KOH. All this information is useful not only to the improvement of a pyrolysis system but also to the better utilization of liquid oil products.

Pyrolysis of oil sludge with additives of sodium and potassium compounds

Oil sludge, if unused, is one of the major industrial wastes requiring treatment from petroleum refinery plants or the petrochemical industry. It contains a large amount of combustibles with high heating values. The treatment of waste oil sludge by burning has certain benefits; however, it cannot provide the useful resource efficiently. On the other hand, the conversion of oil sludge to lower molecular weight organic compounds by pyrolysis not only solves the disposal problem but also has the appeal of resource utilization. The major sources of oil sludge include the oil storage tank sludge, the biological sludge, the dissolve air flotation (DAF) scum, the American Petroleum Institute (API) separator sludge and the chemical sludge. In this study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in northern Taiwan is used as the raw material of pyrolysis. Its heating value of dry basis and low heating value of wet basis are about 10681 kcal kg−1 and 5870 kcal kg−1, respectively. The removal of the moisture from oil sludge significantly increases its heating value. The pyrolysis of oil sludge is conducted by the use of nitrogen as the carrier gas in the temperature range of 380–1073 K and at various constant heating rates of 5.2, 12.8 and 21.8 K min−1. The pyrolytic reaction is significant at 450–800 K and complex. For the sake of simplicity and engineering use, a one-reaction kinetic model is proposed for the pyrolysis of oil sludge, and is found to satisfactorily fit the experimental data. The activation energy, reaction order and frequency factor of the corresponding pyrolysis reaction in nitrogen for oil sludge are 78.22 kJ mol−1, 2.92 and 9.48 × 105 min−1, respectively. For precise use, the two- and three-reaction models are proposed to describe the pyrolysis results. Among the three models proposed, the three-reaction model gives the best fit. These results are very useful for the proper design of the pyrolysis system of the oil sludge under investigation.

© 2000 Society of Chemical Industry

Resources recovery of oil sludge by pyrolysis: kinetics study

Previous efforts were made to convert the oil sludge into useful resources such as lower molecule organic compounds and carbonaceous residues by pyrolysis with the carrier gas of N2 The liquid products (condensates of gases at 298 K) obtained from the pyrolysis of oil sludge are close to diesel oil However, they contain a significant amount of vacuum residues of about 957 wt %, which decrease the qualities of liquid products In the present study, the oil sludge from the oil storage tank of a typical petroleum refinery plant located in the northern Taiwan is used as the raw material for the pyrolysis The influences of using inexpensive and nonharmful additives on the possible improvement of the pyrolysis of oil sludge are investigated The additives employed include two groups:  (1) aluminum compounds (Al, Al2O3, and AlCl3), and (2) iron compounds (Fe, Fe2O3, FeSO4·7H2O, FeCl3, and Fe2(SO4)3·nH2O) For the increases of conversion X, the additives provide the offers on the order of Fe2(SO4)3·nH2O > Fe2

Chao-Hsiung Wu

Papers

On the thermal treatment of plastic mixtures of MSW: Pyrolysis kinetics

Major Products Obtained from the Pyrolysis of Oil Sludge

Pyrolysis of oil sludge with additives of sodium and potassium compounds

Resources recovery of oil sludge by pyrolysis: kinetics study

Use of Inexpensive Additives in Pyrolysis of Oil Sludge