Use of Tyre Pyrolysis Products as Recycled Raw Materials for the Production of Composite Suspension Fuel

Abstract

Composite suspension fuel (CSF) is a viable alternative not only to solid coal but also to fuel oil and diesel fuel. The issue with combined systems is the low stability and heterogeneity of the distribution of solid particles, which causes an increase in the viscosity of dispersed systems. Studies have shown that it is possible to use pyrocarbon, which is made from used car tyres, as a fuel for boats. Systems based on pyrocarbon without additives have high viscosity values. To regulate the rheological properties and stabilize the CSF, additives such as dispersants, plasticisers, and stabilisers are used. Research has been done into how dispersants affect the properties of composite suspension fuel (CSF). They used additives like carboxymethylcellulose (CMC), sodium lignosulfonate (LSTNa), naphthalene formaldehyde (NF), the condensation product of β-naphthalene sulfonic acid and formaldehyde (C-3), and humic acids. Studies of the flow of CSF based on pyrocarbon are in line with studies of the surface of pyrocarbon using electrokinetic methods. It is estimated that the surface of unmodified pyrocarbon has a positive charge at a pH of 2-10. The addition of reagents causes a change in the surface charge of the pyrocarbon and surface recharging. The best results have been obtained in CSF formulations with additives containing a sulfur group, such as C-3, NF, and LSTNa in a mass concentration of 2%. The resulting suspensions have an apparent viscosity of no more than 0.8 Pa·s, which makes it possible to use the obtained CSF as a liquid fuel suspension with a solid phase concentration of up to 60% by mass.