The turbidity of the graywater system is high, and the selection of flocculants was unsuccessful
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Consultation: Recently, for a space furnace coal gasification ash water system with three separate systems, the coal quality is the same; however, the size and pressure of the gasification furnaces differ, which results in differences in the quality of the ash water and in the type of flocculant used. Phase 1: High turbidity; many different models were tried, but the problem was still not resolved. During the pilot test, when 5–10 ppm of flocculant was added, the black water remained almost unchanged, and the water quality stayed turbid. The turbidity at the site is very high ； Phase 2: The parameters of the gasification furnace are the same as those in Phase 1, and the phenomena observed during pilot testing are also identical to those in Phase 1. However, oddly enough, the actual performance on-site was fairly good, with the turbidity remaining around 20 ； Phase 3: The process parameters of the vaporization furnace are higher than those in Phase 1 and Phase 2. During pilot tests, a concentration of 3–5 ppm yielded excellent results, with turbidity remaining at around 10 NTU; however, in actual operational conditions the performance was poor, with turbidity exceeding 50 NTU. The phenomena in the pilot tests and in the field were exactly the opposite of those in Phase 2 (Phase 2 showed poor results in pilot tests, but decent results in the field) ； The pilot tests in phase 3 showed good results, but the actual performance on-site was poor).
This post was last edited by caocheng on 2025-1-3 09:22. When addressing the issue of selecting flocculants for the ash water treatment system in space furnace coal gasification, multiple factors need to be taken into account, including the size and pressure of the gasification furnace as well as the quality of the coal. Based on the information you provided, although the coal quality is the same for all three systems, differences in the process parameters of the gasification furnaces result in variations in the quality of the ash water, which in turn affects the selection and effectiveness of the flocculants. I. Analysis and Recommendations 1. Phase 1 system: - High turbidity and poor performance of the flocculant may be due to the type of flocculant used or an insufficient dosage. It is recommended to reevaluate the water quality parameters, including pH value, organic matter content, and types of suspended solids, and to adjust the type of flocculant or increase its dosage based on these parameters. - It is possible to try combining various flocculants; for example, using iron-based flocculants for pre-treatment, followed by the use of polyaluminum chloride (PAC) or polyacrylamide (PAM) for further treatment. 2. Phase II system: – Although the results in pilot tests were poor, the performance in actual operation was acceptable, which may be related to the operating conditions (such as mixing speed, and the location and method of adding flocculants). It is recommended to carefully document and compare the differences between pilot tests and field operations in order to identify the key influencing factors. - It is also advisable to consider regular cleaning and maintenance of the system, in order to prevent blockages or wear in the pipes or equipment from affecting the flocculation efficiency. 3. Phase 3 system: - There is a significant difference between the results of pilot tests and those observed in actual operation; it is recommended to check for any equipment failures or operational errors in field applications. For example, whether the flocculant dosing system is uniform, and whether there is sufficient mixing and reaction time, etc. - It is possible to try adjusting the location where the flocculant is added or changing the water flow path in order to enhance the flocculation effect. II. Conclusion: Due to the different process parameters of the three systems, the water quality and the reaction with the flocculant also vary. It is recommended to conduct detailed water quality analysis and pilot tests for each system, and adjust the type of flocculant and the dosage strategy according to the actual conditions. At the same time, strengthen the monitoring and adjustment of on-site operations to ensure that the efficacy of the flocculant meets the expected levels. .