Control system and control method for supercritical water system depressurization

Abstract

The invention discloses a control system and a control method for supercritical water system depressurization. The system is mainly composed of a resistance water tank, a resistance water pump, a capillary pressure reducer, a back pressure valve, an adjustment value and a related stop valve. Through switching between the back pressure valve branch and the capillary pressure reducer branch, adjustment on the system pressure in the case of startup, shutdown and normal operation of the system is realized respectively. On the basis of effectively preventing the problems of abrasion and blockage of valve inner elements existing during the solid particle-containing material depressurization process, the system pressure can be accurately controlled. In addition, the operation complexity during the system startup and shutdown processes can be reduced through the back pressure valve branch, and the operation reliability is improved.

Description

【Technical field】 [0001] The invention belongs to the fields of environmental protection and chemical industry, and in particular relates to a control system and method for depressurizing a supercritical water system. 【Background technique】 [0002] Supercritical water (Supercritical Water, SCW) refers to water whose temperature and pressure are above its critical point (374.1°C, 22.1MPa). Compared with ordinary liquid water, various physical and chemical properties of supercritical water have undergone significant changes: the hydrogen bonds between water molecules are weakened; the density, viscosity, and ion product are significantly reduced, and the diffusion coefficient is higher; the dielectric constant becomes Very small, roughly equivalent to the dielectric constant of general organic solvents under standard conditions. Therefore, the solubility of supercritical water to inorganic salts is extremely small, but it has a strong solubility to O2 and most organic substa...

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Problems solved by technology

[0005] The capillary depressurization method has significant advantages over a single valve decompression, but at the same time of depressurization, the function of precise control of the system pressure must be realized, which requires proper connections between capillary depressurizers, valves, pumps and other equipment mode and control operation method, the control method of capillary depressurization in the supercritical water treatment system has not been reported yet.

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