Application of cationic polyacrylamide Zetag 7645 Zetag8110

Cationic polyacrylamide and granular cationic polyacrylamide (CPAM) are linear polymer compounds, which can form hydrogen bonds by affinity and adsorption with many substances due to its various active groups. Mainly flocculation negatively charged colloid, except the turbidity, decoloring, adsorption, adhesion, and other functions, suitable for dyeing, papermaking, food, building, metallurgy, mineral processing, coal, oil field, aquatic products processing and fermentation industries such as waste water treatment of organic colloid content is higher, especially suitable for urban sewage, urban sewage sludge, sludge and other industrial sludge dewatering treatment.

Product form cationic polyacrylamide can be divided into two forms according to the different form of solid material and emulsion, the most widely used on the market is solid material, and cationic polyacrylamide emulsion as a new form of product market application is less.

Technical indicators

Appearance: white particle solid content: ≥88% Molecular weight: 8-12 million water insoluble matter: ≤2%

Residual unit: ≤0.1% cationic concentration: 10-70% Dissolution time: ≤60 minutes

Features 1, water solubility is good, can also be completely dissolved in cold water. Cationic polyamide

2, add a small amount of cationic polyacrylamide products, can be subject to great flocculation effect. Generally, only 0.01~10ppm (0.01~10g/m3) is needed to give full play to the effect.

3, at the same time the use of cationic polyacrylamide products and inorganic flocculant (polymeric ferric sulfate, polymeric aluminum chloride, iron salt, etc.), can show greater effect.

The degree of hydrolysis of polyacrylamide solution refers to the weak ion in polyacrylamide solution combined with water, the formation of weak alkaline or weak acidic ability, or the formation of weak acid in polyacrylamide aqueous solution and the formation of weak base ability. For strong acids and bases, the higher the degree of ionization, the stronger the corresponding acid base, and their hydrolysis degree is weaker. For some soluble polyacrylamide, the greater the degree of ionization corresponding to ionized more ions, and their degree of hydrolysis is weaker. In general, the higher the degree of ionization, the weaker the degree of hydrolysis, conversely, the lower the degree of hydrolysis, the greater the degree of hydrolysis.

Functions due to cationic polyacrylamide has the following functions:

1, clarification and purification effect 2, settlement promotion effect; 3. Promoting effect of filtration; 4, thickening and other effects.

Therefore, it can fully meet the requirements of waste liquid treatment, sludge concentration and dehydration, mineral processing, coal washing, paper making and other aspects.

1, PAM has a unique decolorization ability, mainly used in the decolorization of dye plant wastewater with high chroma, suitable for the variety of reactive, acidic and disperse dyes. 2, can also be used for textile, printing and dyeing, printing ink and other industrial wastewater treatment. 3. The decolorization rate of the product to wastewater can reach more than 95%, and the removal rate of COD is between 40-70%.

Usage Guide 1) Polyacrylamide is an organic polymer compound, can be divided into anionic polyacrylamide, cationic polyacrylamide and non-ionic polyacrylamide, for white powder or particles, soluble in water, but the dissolution rate is very slow;

2) anionic polyacrylamide is generally used for wastewater treatment flocculant, cationic type is generally used for sludge dehydration;

3) As a flocculant, the drug dosage is generally 1-2ppm, that is, the drug dosage per 1 ton of wastewater is about 1-2G;

4) When used, anionic type is generally prepared into about 0.1% aqueous solution, cationic type can be prepared into 0.1-0.5%;

5) when preparing the solution, add water in the dissolving tank first, then open the blender, and then add PAM slowly along the vortex, PAM can not be quickly put into one time, otherwise PAM will agitate to form "fish eyes" and can not dissolve;

6) After adding PAM generally should continue to stir for more than 30 minutes to ensure that it is fully dissolved;

7) Dissolved PAM should be used as soon as possible, anionic type generally not more than 36h, cationic solution is easy to hydrolysis, should be used within 24h.

Solubility as a polymer cationic polyacrylamide dissolution rate factors mainly involve the following two elements:

Molecular diffusion

The dissolution of substances is a process of mutual penetration and diffusion between solute and solvent molecules, so the movement ability of solute and solvent molecules is an important factor affecting the solvent time. Because solute molecules are much larger than solvent molecules, their diffusion rates differ greatly. In the initial stage of dissolution, only water molecules diffuse to polyacrylamide unilaterally, and polyacrylamide molecules can not diffuse to the direction of water, so the first swelling is the necessary stage of dissolution.

Hydrogen bonds and tangles

Hydrogen bonds can be formed between the amide side groups within and between the molecular chains of polyacrylamide. Hydrogen bond is the strongest intermolecular force, high molecular weight polyacrylamide molecular chain there are a lot of hydrogen bond; At the same time, the high molecular weight of polyacrylamide molecular chain is very long, long molecular chain must be curly, they are bound to tangle together. Therefore, if the rapid dissolution of polyacrylamide needs to rely on the rapid infiltration and attack of solvent water molecules, net hydrogen bond dissociation and molecular chain untangling.

The dissolution rate of polyacrylamide is related to its molecular weight, ionic degree, molecular geometry, dissolution temperature, mixing and feeding mode.

The dissolution rate decreases with the increase of molecular weight and the increase of chemical crosslinking degree. In the process of powder lu production, high drying temperature and long drying time will make the product branch or slightly cross-linked, and prolong the dissolution time and even some insoluble matter. Some manufacturers because the production process is not mature, there will be a very slow dissolution rate, after a certain time of insoluble things.

The increase of dissolution temperature and stirring rate is beneficial to molecular diffusion and dissolution rate. However, higher dissolution temperature (more than 50 degrees Celsius) and strong stirring rate will make polyacrylamide degradation, poor performance. This is especially prominent for powder type products.

A precipitate is a substance formed during a chemical reaction that is insoluble in the solution in which the reactants reside. Precipitation removal under the action of gravity. This is a physical process, simple and easy to operate, good effect, is one of the important technologies of sewage treatment.

According to the nature and concentration of suspended matter and flocculation performance of polyacrylamide, precipitation can be divided into natural precipitation, flocculation precipitation, regional precipitation. The concentration of suspended particles in the zone precipitation is high (above 5000mg/L), and the sedimentation of particles is affected by other surrounding particles. The relative positions of particles remain unchanged, forming a common subsidence as a whole, and there is a clear mud-water interface with the clarified water. Regional precipitation occurred in both secondary sedimentation tank and sludge thickening tank.

The concentration of suspended solids in wastewater is not high, and it does not have the performance of condensation. In the process of precipitation, solid particles do not change shape, nor do they adhere to each other, and each completes the precipitation process independently. (at the beginning of grit chamber and the early stages of the pond, precipitation) compression precipitation occurred in the process of the settlement of high concentration of suspended particles, because of the high concentration of suspended particles, particles has integrated mass structure between each other, touch each other, support each other, the lower water between particles in the upper particles under the action of gravity by extrusion, concentrated sludge. There is compression precipitation in the process of polyacrylamide thickening in sludge hopper of secondary sedimentation tank and sludge thickening in the thickening tank. Free precipitation occurs when the concentration of suspended solids in water is not high, the suspended solids do not interfere with each other in the precipitation process, and the particles precipitate separately, and the precipitation trajectory of particles is linear. During the whole precipitation process, the physical properties of particles, such as shape, size and specific gravity, do not change. The precipitation of such particles in the sedimentation tank is free precipitation.

Flocculation precipitation is the process of flocculation and precipitation of particulate matter in water. After adding coagulant in water, the colloidal and dispersed particles of suspended solids form floccule under the interaction of molecular force, and they collide and condense with each other in the sedimentation process, and their size and mass become larger and the sedimentation rate increases. The removal rate of suspended solids depends not only on the sedimentation rate but also on the sedimentation depth. Flocculation and precipitation will occur in the process of surface water alum flower, organic suspended solids in domestic sewage and activated sludge.

The way in which a drug is added

Gravity infusion and pressure infusion are used for drug infusion. Regardless of which infusion method, liquid lifting equipment should be set up from the solution pool to the solution pool to the liquid infusion point. The commonly used liquid lifting equipment is metering pump and water injector.

1. Gravity adding the use of gravity to add the agent in the water pump suction pipe or suction well suction bell mouth, the use of pump impeller mixing.

2. Pressure adding the use of water pump or water injector to add the agent to the original water pipe, suitable for adding the agent to the pressure water pipe, or need to add to the higher elevation, far from the water purification structure.

3. Pump feeding pump feeding is in the solution pool to lift the liquid to the pressure pipe, there is a direct use of metering pump and the use of acid resistance to enhance the role.

Generally before use should be made into standby 0.1% ~ 0.5% of dilute solution, it is best not to store too long to make good solution, the concentration range of solution needs to be further diluted before use as 0.01 ~ 0.05 solution, the reason is that can be more ribs in the flocculating agent in the dispersion in the suspension system, can reduce the dosage, And can get better flocculation effect!

Many sewage treatment plants use cationic polyacrylamide as sludge dewatering agent. In the sludge dewatering process at the later stage of sewage treatment, the dosage of sludge dewatering agent is different according to the sludge type.

To know the relative accuracy of the dosage of sludge dehydrating agent, first understand these parameters, the moisture content of sludge, mud cake moisture content, mud quantity, dosage, dispensing concentration, etc

Sludge moisture content: the percentage of the weight of water contained in the sludge to the total weight of the sludge is called sludge moisture content.

Mud cake moisture content: the ratio of the weight of water contained in the mud cake to the total weight of sludge is called mud cake moisture content.

It's also done by the following formulas

1. Dosage mg/L= dosage quality/treatment water quantity/dispensing concentration

2, treatment water dosage = treatment water m3/h* dosage g/m3

3. Dry mud amount = treated water * [(1- sludge moisture content)/(1- mud cake moisture content)]

4. Reagent consumption g/m3 per ton of dry mud = dosage/dry mud quantity

The above calculation results may be relatively large error, only for reference in sewage operation. Actual drug consumption should be carried out in actual machine operation test.

Introduction of cationic polyacrylamide in wastewater treatment

1. Powdery cationic polyacrylamide is often used in organic wastewater: usually let sewage suspended particles with negative charge of sewage flocculation precipitation. It is very effective to rely on the presence of positive electricity to quickly clarify wastewater in acidic or alkaline media of positive ion in flocculation unit. In addition to powdery polyacrylamide, polyaluminum chloride and anionic polyacrylamide molding materials are also widely used in organic wastewater treatment.

2. Alcohol plant waste water, brewery wastewater and gourmet powder factory wastewater, sugar refinery wastewater, meat factory waste water, beverage factory waste water, textile dyeing and all kinds of sewage in the engineering of wastewater treatment plant, with various organic solvent and inorganic and organic sulfides, hydrocarbons and chlorine gas, oil, mercury and other harmful to the environment, can use PAM flocculation after discharge. It can also be used as mud treatment agent in oilfield development process, selective water blocking agent, water injection thickening agent, textile printing and dyeing process softener, electrostatic prevention agent and general sterilization, disinfectant, etc.

3. Used for water supply purification, water/oil system demulsification, oily wastewater treatment, wastewater recycling and sludge dewatering, etc. Polyacrylamide can effectively reduce the frictional resistance of fluid, adding trace polyacrylamide in water can reduce resistance by 50-80%.

Use 1), used for sludge dewatering according to the nature of sludge can choose the corresponding model of the product, can effectively in the sludge into the pressure filter before sludge dewatering, dehydration, flocculation, non-stick filter cloth, pressure filter is not scattered, flow mud cake thick, dehydration efficiency is high, mud cake moisture content below 80%. 2), used for the treatment of domestic sewage and organic wastewater, the product in the compatibility or alkaline media are positive, so the suspended particles in sewage with negative charge of sewage flocculation precipitation, clarification is very effective. Such as the production of grain alcohol wastewater, papermaking wastewater, waste water of urban sewage treatment plant, beer wastewater, gourmet powder factory wastewater, sugar water, high organic content Waste water, waste water feed, textile printing and dyeing wastewater, etc., with cationic polyacrylamide than with anionic, nonionic polyacrylamide or inorganic salts effect is several times or tens times higher, because this kind of wastewater with negatively charged.

3), used for the treatment of tap water with river water as the source of flocculant, less dosage, good effect, low cost, especially with inorganic flocculant compound use effect is better, it will become the treatment of the Yangtze River, the Yellow River and other watershed of the tap water plant efficient flocculant.

4), strengthening agent and other additives for paper making. Improve the retention rate of filler, pigment and paper strength.

5), used for oil field economic AIDS, such as clay anti-swelling agent, oil field acidification with thickening agent.

6), used for textile sizing agent, size stable performance, less falling pulp, fabric breakage rate is low, clean cloth.

Use process: the use of polyacrylamide should follow the following principles:

1, granular polyacrylamide flocculant can not be directly added to sewage. It must be dissolved in water before use, and its aqueous solution is used to treat sewage.

2, dissolved granular polymer water should be clean (such as tap water), not sewage. Normal temperature water can, generally do not need to add temperature. Water temperature below 5℃ is very slow dissolution. The dissolution rate increases with the increase of water temperature, but above 40℃ will accelerate the degradation of polymer, affecting the use effect. Generally tap water is suitable for preparing polymer solutions. Water with strong acid, alkali and high salt content is not suitable for preparation.

3, the selection of polymer solution concentration, it is recommended to be 0.1% - 0.3%, that is, 1 liter of water add 1g - 3g polymer powder.

The following factors should be considered in the selection of PAM concentration:

Mixing tank is small and daily dosage is large. It is recommended to mix slightly stronger (e.g. 0.3%).

When the polymer molecular weight is very high, it is recommended to mix slightly thinner (such as 0.1%).

When polymer solution is thrown into sewage, if the dispersion condition is not good due to equipment reasons, it is recommended to be slightly diluted.

In short, excessive polymer concentration will cause excessive load of stirrer motor and poor dispersion after entering sewage, affecting the use effect. It helps to use it sparsely.

4, the prepared solution should not be transferred by centrifugal pump, so as to avoid shear degradation of polymer caused by high-speed rotating blades. The specific method of preparation is as follows: add a certain amount of water into the dissolving device (such as the beaker in the laboratory, and the matching tank in the factory), calculate the amount of powdery polymer required by the amount of water and concentration, and weigh the polymer.

(1) According to the polymerization formula, weigh acrylamide aqueous solution, quaternary ammonium salt monomer and deionized water into the mixing container.

(2) Stir for 15: min, and adjust pH to a predetermined value with a small amount of concentrated HCl solution.

(3) After adjusting the temperature to a predetermined value, transfer the solution into a polymeric bag in the insulation container with a certain amount of azo initiator, and install the temperature recorder. Nitrogen was blown for 30min to remove oxygen. (Initiator and dosage v65:1000mGE /L; PA - 5:20 MFF /L: Per: