STABILIZATION OF WATER-COAL COMPO­SITE FUELS USING CARBON MICRO-NANO­MATERIALS AND AMINO ALCOHOLS

Abstract

The study investigated the potential of stabilizing composite water-coal fuel (CWCF) by adding carbon micro-nanomaterials obtained through the plasma-chemical conversion of organics-containing wastewater and amino alcohols. The study focused on systems based on anthracite with a solid phase concentration of 62%. Two amino alcohols, 2-amino-­2-methyl-1-propanol (AMP) and 2-amino-­2-ethyl-1,3-propanediol (AEPD) were used at concentrations of 0.25%, 0.5%, 1%, and 2.5% by weight of CWCF.
 The low stability and heterogeneity of coal particle distribution in organic liquids cause an increase in the viscosity of dispersed systems in combined systems. To regulate the rheological properties and stabilize the CWCF, chemicals such as dispersants, plasticizers, and stabili­zers are added. The CWCF 's properties can be improved by using additives such as sodium, calcium, and magnesium lignosulfonates, and naphthalene sulfonic acids. However, these reagents may not provide the desired properties of coal slurries in organomineral environments. Therefore, substitutes for these pro­ducts need to be found.
 Amino alcohols are commonly used as dispersants and stabilizers, especially in the production of water-based paints. They are low in cost, low in toxicity, and serve as anti-corrosive agents and pH stabilizers without causing excessive foaming. To strengthen the spatial structure, reactive particles such as carbon micro- and nanomaterials (CNM) can be introduced into the CWCF. Unlike polyelectrolytes and surfactants, CNM particles can have a varying number of active centers depending on the method of formation. By varying the properties of CNMs, it is possible to increase the number of contact centers and form a spatial grid without increasing the concentration of surfactants and polyelectrolytes. This is because contact interactions are activated during grinding, forming a new surface with energy-saturated active centers. As a result, the concentration of the system can be increased, and the calorific value of the fuel can be increased as well. However, the presence of an organic component can render mechanochemical activation ineffective by shielding active sites with large organic molecules. Therefore, identifying the most effective stabilizer reagents and deve­loping technology for their introduction into the dispersed system is a crucial and intricate problem in obtaining CWCF
 The study revealed that the ξ potential of anthracite particles is 40–45 mV in the pre­sence of amino alcohols. Sedimentation stabi­lity in the presence of highly dispersed carbon additives increases from 5–6 to 10–14 days, i.e., almost twice. The introduction of highly dispersed carbon leads to an increase in the effective viscosity of the systems and can be recommended for controlling the fluidity of the CWCF. The technical and operational requirements are best met by the CWCF containing 0.25% AMR and 1% highly dispersed carbon.