A kind of coal gasification black ash water self-adaptive reducing hardness type gray water scale inhibitor dispersant and its application

Abstract

The invention discloses a coal gasification black gray water self-adaptive reducing hardness type gray water scale inhibitor dispersant and its application, including the following content: by optimizing the type, group, structure and molecular weight of the gray water scale inhibitor dispersant, the corresponding pH is controlled range, so that the hardness-reducing gray water scale inhibitor dispersant plays the role of scale inhibition and dispersion in the gray water section, plays the role of crystal nucleus and coagulation aid in the flash evaporation and black water clarification section, and effectively reduces the hardness of the gray water system , so that the gray water system can operate well under the existing scale-inhibiting dispersion-crystal mud sedimentation system, no need to configure additional hardness removal devices, reduce the complexity of the design of the gray water system, and reduce the investment and operating costs of enterprises .

Description

technical field [0001] The invention belongs to the field of operation of a coal gasification black ash water system crystal mud sedimentation-scale inhibition dispersion binary system, and specifically relates to a coal gasification black ash water self-adaptive reducing hardness gray water scale inhibition dispersant and its application. Background technique [0002] After the coal gasification black water is flashed and flocculated, gray water dispersant is added and returned to the system. Unlike the circulating water system, the gray water has high alkalinity, high hardness, high temperature, high pressure, and the pH changes greatly before and after flashing. Medium soot contact and other characteristics. Therefore, the chemicals and management methods that are suitable for circulating water systems are not suitable for gray water systems. [0003] Usually we use the Langer coefficient (k value) to measure the scaling tendency of various scaling factors in water. The...

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Problems solved by technology

However, if the coal gasification gray water system also adopts the chelation method, a large amount of solid coal ash will dissolve in water under the acidic environment of the gasifier, and the water hardness saturation will be too high. After the subsequent flash phase change process, Calcium carbonate precipitates are formed in an instant, causing a large amount of scaling in pipelines and equipment. In severe cases, even the gasifier will be seriously blocked, causing the system to be shut down for maintenance

[0020] Moreover, the commercially available gray water dispersant claims to have good scale inhibition effect between pH 7-9, but in fact, the gasification device in this range cannot achieve long-term stable operation

[0021] In addition, the molecular weight of chelating gray water dispersants is generally small, resulting in too small suspended particles formed in the sedimentation tank, which are not easy to be flocculated by PAM, and gray water can only be used under high turbidity, high hardness and high alkalinity running, and the gray water sent to the sewage system for treatment is not easy to handle, causing more troubles

[0022] Therefore, following the experience of circulating water, the designed commercially available gray water dispersant is not suitable for the dual system of coal gasification gray water flocculation-scale inhibition and dispersion

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