Noncatalytic Reformation of JP-8 Fuel in Supercritical Water for Production of Hydrogen

摘要

A novel process is developed where hydrogen is generated via direct noncatalytic reformation of liquid hydrocarbon fuels such as diesel and JP-8 fuel in supercritical water. In this process, supercritical water functions as a reforming agent and as a solvating reaction medium. The high enthalpy level of supercritical water and the extraordinary solubility of hydrocarbon fuel components in supercritical water allow the reformation reaction to proceed without a heterogeneous catalyst that is typically required for the conventional reformation process. Typical operating temperature and pressure ranges for this reformation process are: 650℃-825℃ and 22-33 MPa. The process feasibility of the supercritical water reformation of JP-8 fuel was demonstrated in a tubular reactor (Generation-I SWR Reactor) made of Inconel-625 alloy (Grade 1) whose dimensions are 2.54-cm internal diameter and 183-cm internal length. The following scientific and technological issues were investigated in-depth: (a) long-term continuous reactor operability, (b) capability of handling high sulfur containing liquid fuel without cumbersome pre-desulfurization, (c) potentially varying supercriticality of the reactant and product mixtures along the reactor length, (d) principal reactions in the process chemistry, (e) coke formation and its prevention, (f) competitive productivity between H2 and CH4 and its significance, (g) feasibility of autothermal mode of operation by co-feeding air or oxygen into the reactor, (h) effects of fuel components on the overall process efficiency, and (i) desired mechanical properties of the reactor material of construction.