It is a kind of flocculant that can accelerate the formation of large flocculent or water suspension. It plays an important role in wastewater treatment, oilfield industry, protein extraction, metallurgy, papermaking and other fields. China's flocculant industry is a fully competitive industry. At present, the overall production and marketing are basically in a state of balance, and the supply of individual fields is in short supply. China has become the world's largest producer and seller of flocculant products, and there are more than 100 flocculant manufacturers in China. At present, the flocculants commonly used in our market are inorganic polymer flocculants PAC, PFS and synthetic organic polymer flocculants PAM. From low molecular to high molecular, from inorganic to organic, from single to complex, the pursuit of high efficiency, low cost, environmental protection is the general trend of the development of flocculant industry. Compared with inorganic flocculant, organic polymer flocculant has a good purification effect on both organic and inorganic matters. At the same time, it has many advantages, such as low dosage, low cost, low toxicity, wide range of pH application, bulky flocs, fast flocculation speed, short treatment time, less sludge and easy treatment. It is increasingly favored by the market.
1、 What is the mechanism of flocculant?
The colloidal particles in water are small, surface hydrated and charged, which make them stable. After adding flocculant into water, they are hydrolyzed into charged colloids and the ions around them form micelles with electric double layer structure. The collision chance and times of colloidal impurity particles in water and the micelle formed by flocculant hydrolysis were promoted by rapid stirring after dosing. Under the action of flocculant, the impurity particles in water first lose their stability, then agglomerate into larger particles, and then precipitate or float in the separation facility.
The product gt of the velocity gradient g and the stirring time t can indirectly represent the total number of particle collisions in the whole reaction time, and the coagulation effect can be controlled by changing the GT value. Generally, the GT value is controlled between 104 and 105. Considering the influence of the concentration of impurity particles on the collision, the GTC value can be used as the control parameter to characterize the coagulation effect, where C represents the mass concentration of impurity particles in the sewage, and the GTC value is recommended to be about 100.
The process of promoting the rapid diffusion of flocculant into water and mixing with all wastewater is mixing. The process that the impurity particles in water react with the flocculant, lose or reduce the stability by compressing the electric double layer and electric neutralization, and form micro floccules is called coagulation. Under the agitation of bridging material and water flow, the micro flocs grow into large flocs through adsorption bridging and sediment net catching mechanism, which is called flocculation. The combination of mixing, coagulation and flocculation is called coagulation. The mixing process is generally completed in the mixing tank, and coagulation and flocculation are carried out in the reaction tank.
2、 Flocculant saving measures
In addition to the above factors, there are also some measures to save drugs, such as increasing the mixing times of liquid medicine pool, reducing the precipitation of solid particles, stabilizing the drug properties, and achieving the purpose of saving drug consumption.
1. If you want to save cost in the use of Polyacrylamide, you need to choose the type of polyacrylamide first. The principle is to choose the polyacrylamide with the best wastewater treatment effect. The expensive one is not necessarily the best one, and you should not try to be cheap, which will lead to poor wastewater treatment effect, but will increase the cost. Choose the one that not only reduces the water content of sludge, but also has low dosage of reagent The agent. First of all, flocculation experiments are carried out on the provided reagent samples in the laboratory, and two or three kinds of reagents with good experimental effect are selected, and then the computer experiments are carried out respectively to observe the final sludge discharging effect, so as to determine the final reagent varieties.
2. Polyacrylamide is generally solid particles. When using an aqueous solution with a certain solubility, the concentration is usually between 0.1% and 0.3%. If it is too thick or too thin, the effect will be affected, the reagent will be wasted and the cost will be increased,
The water used to dissolve the granular polymer should be clean (such as tap water), not sewage. Water at normal temperature is enough, generally without heating. When the water temperature is lower than 5 ℃, the dissolution is very slow. With the increase of water temperature, the dissolution rate is accelerated, but the degradation rate is accelerated when the temperature is above 40 ℃, which affects the use effect. Generally, tap water is suitable for preparing polymer solution. The water with strong ACID, strong alkali and high salt content is not suitable for preparation.
3. Pay attention to the curing time in the preparation of medicament, so that the medicament should be fully dissolved in water, not caking, otherwise, it will not only cause waste, but also affect the effect of sludge, at the same time, it will cause blockage to the filter cloth and pipe, resulting in repeated waste. When the solution is prepared, the storage time is very limited. Generally speaking, when the concentration of the solution is 0.1%, the non anionic polymer solution does not exceed one week; the cationic polymer solution does not exceed one day.
4. After the preparation of the agent, in the process of dosing, we should pay attention to the change of the quality of the mud in and the effect of the mud out, and timely adjust the dosage of the agent to achieve a better dosing ratio.
5. The medicine should be stored in a dry warehouse, the medicine bag should be sealed, in use, as much as possible to use, and the unused medicine should be sealed to avoid moisture. It should be noted that there should be no more configuration in the preparation of medicine. The medicine liquid which has been kept for a long time is easy to hydrolyze and can no longer be used.
