Energy yield from wastewater by supercritical water oxidation process: Experimental validation and simulation from the viewpoint of energy system

Safety Management and Accident-Control Strategy for a Commercial-Scale Plant for Supercritical Water Oxidation of Sludge

“…For the normal shutdown process, the feedstock of the system is changed from sludge to water gradually, by adding water into the sludge tank (1). The temperature of the reactor ( 7) is gradually decreased with a decreasing rate of 100 • C per hour, which is achieved by interlocking the temperature signal from the reactor (7) and the power of the electrical heater (5). According to our estimation, it takes about 6 to 8 h for the system to shut down by the normal procedure.…”

“…(1) Overpressure accident: if overpressure occurs in the electrical heater (5), the first step is to change the location of the heating module where salt precipitation forms, as introduced in Section 3.2. If the overpressure occurs in the heat exchanger (4) or the reactor (7), the fast shutdown procedure should be carried out directly. (2) Over-heating accident: the first step in handling an over-heating accident is to cool down the place where the temperature is exceeding the normal.…”

“…If it occurs in the heater (5), the heating module of the heater (5) should be turned off immediately, and all the dismountable thermal-insulation material should be removed to help cooling. If over-heating occurs in the heat exchanger (4) or the reactor (7), the desuperheater ( 6) is used for fast cooling, and then the fast-shutdown procedure will be carried out. (3) Opening of pressure relief valves: the opened relief valve will re-seat when the pressure decreases, back to the set-point.…”

“…Supercritical water oxidation is a powerful organic-waste treatment method that can completely decompose the organic materials without a pre-drying procedure and secondary pollution [5][6][7]. Compared with other advanced oxidation technologies, there are several advantages to SCWO.…”