Softening and coagulating treatment process of gas scrubbing water

A technology for gas washing and treatment process, which is applied in water softening, flocculation/sedimentation water/sewage treatment, etc. It can solve the problems of increased changes in water treatment equipment and large equipment investment, and achieves remarkable effects, simple operation and controllability. strong effect

Inactive Publication Date: 2004-09-08
SHANGHAI HUAYI ENERGY CHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to reduce the hardness and turbidity of the water system to ensure the normal operation of the system, more infrastructure needs to be built, equipment investment is large, and the original water treatment equipment needs to be greatly modified and increased.

Method used

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  • Softening and coagulating treatment process of gas scrubbing water
  • Softening and coagulating treatment process of gas scrubbing water

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] attached figure 1 It is a schematic flow chart of the softening coagulation process of Embodiment 1 of the present invention.

[0019] In the coal gasification device, the water from the gas scrubber is mixed with the water from the gasification furnace with a solid content of 0.44% and a temperature of 220-230°C with high solid content and high hardness (referred to as black water). , sent to the settling tank through pipeline 2, the calcium hardness in the water is 800~2000mg·L -1 (as CaCO 3 count). The black water is added from the descending pipeline in the center of the settling tank. In the pipeline before adding, use a pump to inject a sodium carbonate solution with a concentration of 5% to 10% through pipeline 1, and the flow rate is about 0.2% to 0.5% of the black water flow rate. %, sodium carbonate solution and black water are fully mixed in the pipeline and then enter the settling tank. Add polyacrylamide solution into pipeline 5, its relative molecular ...

Embodiment 2

[0022] The water to be treated is the gas washing circulating water of a steel plant, with a hardness of 900mg·L -1 (as CaCO 3 meter), the content of suspended solids (coal ash) is 2g·L -1 , the coagulant used is polyacrylamide (molecular weight: 12 million) polyferric sulfate.

[0023] (1) Add 2mg·L -1 Polyacrylamide, large particle flocs are formed during the addition process, 5 minutes after stopping stirring, most of the flocs settle, and after 15 minutes, the absorbance of water is 0.002, and the solution is clear;

[0024] (2) Stir and add 4ml of 5% sodium carbonate solution to 1000ml of water sample at a temperature of 50°C, and add 2mg·L -1 Polyacrylamide coagulant, the solution appears turbid and forms large particle flocs, 5 minutes after stopping stirring, most of the flocs settle, and after 15 minutes, the absorbance of water is 0.001, and the solution is clear;

[0025] (3) Add 4ml of 5% sodium carbonate solution with stirring to 1000ml of water sample at a te...

Embodiment 3

[0028] The industrial water of an enterprise has a pH value of 8.6 and a calcium ion concentration of 820mg·L -1 (as CaCO 3 meter), the temperature is 50°C. Add 20ml of 1% and 2% sodium carbonate solution to 1000ml water sample respectively, and the changes of calcium ion concentration in water are shown in Table 1.

[0029] Table 1 The change of calcium ion concentration in sodium carbonate softening experiment (mg L -1 )

[0030]

[0031] Adding a concentration of 5%, 10% sodium carbonate solution, the experimental results are similar to 1%, 2% sodium carbonate solution.

[0032] The test results show that adding sodium carbonate solution can reduce the calcium ion in the water in a short time. From the reduction value of total hardness and the comparison of the amount of sodium carbonate added, it can be seen that the added sodium carbonate reacts substantially completely.

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Abstract

The softening and coagulating treatment process of gas scrubbing water with high calcium hardness and high solid suspension content is one simultaneous softening and coagulating process, in which sodium carbonate solution of 1-15 % concentration is added in proper position of coagulating deposition tank and the created calcium carbonate crystal and the suspended solid matter coagulate under the action of the coagulant. The present invention features that under the condition of maintaining the water pH unchanged, the concentration of calcium ion and suspended solid in water is reduced in simplified technological process, not expanded apparatus capacity and long term stable operation of the system. The present invention is also suitable for the coagulation and deposition treatment of other industrial effluent with high calcium hardness and high solid suspension content.

Description

technical field [0001] The invention relates to a water quality treatment process in which the softening process and the coagulation process are completed in one step in a settling tank, in particular to the softening and coagulation treatment of washing water with high hardness and high solid content in the coal gasification process. Background technique [0002] In the circulating water system operating under the harsh conditions of gas washing and cooling, since the circulating washing water is in direct contact with gas, coal ash, lime, slag and other substances, there is a carbon dioxide-water dissolution balance in the system water, which forms a dissolved calcium and magnesium ion. -Precipitation balance, resulting in a high content of calcium and magnesium ions in the water, and the pH value is mostly alkaline. Due to the high total hardness, alkalinity and suspended matter content of the water quality, the scaling tendency is serious. If it is not controlled, a larg...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/52C02F1/56C02F5/02
Inventor 蔡兰坤王旭宾张俊顾劲飙
Owner SHANGHAI HUAYI ENERGY CHEM
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