What are the temperature requirements for dispersants and flocculants?

The dispersant for coal-water slurry gasification is different from ordinary dispersants; it has high-temperature resistance and is suitable for use at temperatures below 300 degrees. Regarding flocculants, temperature mainly affects the flocculation effect; therefore, the temperature of the effluent from the flash dryer should be kept below 55 degrees to ensure optimal performance of the flocculants and maintain water quality. I hope this is helpful to you.

There are a wide variety of flocculants, ranging from low-molecular-weight to high-molecular-weight ones, and from single-type to composite types. The general trend is toward those that are inexpensive, practical, non-toxic, and highly effective. Inorganic flocculants are inexpensive, but they can have adverse effects on human health and the ecological environment ； Although organic polymer flocculants require less dosage, result in less sludge production, possess strong flocculation capabilities, allow for easy separation of flocs, and offer effective oil and suspended solids removal, the residual monomers of such polymers have carcinogenic, mutagenic, and teratogenic effects, which limits their scope of application ； Microbial flocculants have promising application prospects due to the absence of secondary pollution and their ease of use. Microbial flocculants are likely to replace or partially replace traditional inorganic polymeric and synthetic organic polymeric flocculants in the future. The development and application of microbial flocculants are on the rise, and their properties and advantages offer broad prospects for the advancement of water treatment technologies. Inorganic flocculants? Editor: They are mainly divided into two categories: iron-based products and aluminum-based products; of course, there are also the polymeric variants of these substances. Inorganic flocculants include aluminum sulfate, aluminum chloride, iron sulfate, iron chloride, etc. Among them, aluminum sulfate was first developed in the United States and remains an important inorganic flocculant in use to this day. Common aluminum salts include aluminum sulfate AL2(SO4)3·18H2O and alum AL2(SO4)3·K2SO4·24H2O. Another category consists of iron salts, such as hydrated ferric chloride FeCl3·6H2O, hydrated ferrous sulfate FeSO4·17H2O, and ferric sulfate. Simple inorganic polymer flocculants, which are primarily polymers of aluminum salts and iron salts. Such as polyaluminum chloride (PAC), polyaluminum sulfate (PAS), polyferric chloride (PFC), and polyferric sulfate (PFS), etc. The reason why inorganic polymer flocculants are more effective than other inorganic flocculants is that they can provide a large number of complexing ions, and they are capable of strongly adsorbing colloidal particles; through adsorption, bridging, and cross-linking, they enable the coagulation of these particles. At the same time, physicochemical changes occur, neutralizing the charges on the surfaces of colloidal particles and suspended solids, thereby reducing the δ potential. This causes the colloidal particles to shift from repelling each other to attracting one another, disrupting the stability of the colloid clusters and leading to collisions between these particles. As a result, flocculent coagulation precipitation is formed; the surface area of such precipitates can reach (200–1000) m2/g, giving them a high adsorption capacity. Ferrous sulfate: Appearance – grayish-white powder or orthorhombic prismatic crystals that form a light yellow powder when in flow state. Sensitive to light. It absorbs moisture easily. It dissolves slowly in water, but more rapidly in the presence of trace amounts of ferrous sulfate in water; it is slightly soluble in ethanol and practically insoluble in propane and ethyl acetate. It hydrolyzes slowly in aqueous solution. Relative density (d18) 3.097. It decomposes at 480°C. The product usually contains about 20% water and is light yellow in color. There are also those containing 9 molecules of crystallization water. Relative density 2.1. 7 molecules of crystalline water are lost at 175℃. Uses: 1. Used for the analysis of silver and the quantitative determination of sugars. Used as a dye. Ink. Purify water. Carving of aluminum. Disinfection. Polymerization catalysts, etc. 2. Analytical reagents, sugar quantification, iron catalysts, mordants, water purifiers, pigments, pharmaceuticals. 3. In the water treatment industry, it is used as a coagulant for water purification and as a treatment agent for sludge. 4. It is used as a mordant and a coagulant for industrial wastewater, as well as in pigments. 5. In medicine, ferric sulfate is used as an astringent and hemostatic agent. 6. Used in electrolytes for zinc-nickel-iron alloys, zinc-iron-cobalt alloys, etc. Aluminum sulfate: It is highly soluble in water. Aluminum sulfate does not dissolve in pure sulfuric acid (it only coexists with it); in sulfuric acid solution, it dissolves in water together with sulfuric acid. Therefore, the solubility of aluminum sulfate in sulfuric acid is the same as its solubility in water. It precipitates at room temperature containing 18 molecules of crystal water, forming aluminum sulfate monohydrate; aluminum sulfate monohydrate is the form commonly produced on an industrial scale. It contains 51.3% anhydrous aluminum sulfate; it does not deliquesce even at 100°C (it doesn’t dissolve in its own crystallization water). It is resistant to weathering and loss of crystalline water, thus relatively stable; it loses water when heated, and decomposes into aluminum oxide and sulfur oxides at high temperatures. When heated to 770°C, it begins to decompose into alumina, sulfur trioxide, sulfur dioxide, and water vapor. Soluble in water, acids, and alkalis; insoluble in ethanol. The aqueous solution is acidic. Hydrolysis produces aluminum hydroxide. Prolonged boiling of an aqueous solution can produce basic aluminum sulfate. Industrial products appear as grayish-white flakes, granules, or lumps; they take on a pale green color due to the presence of low-level iron salts, and their surfaces turn yellow as a result of the oxidation of these iron salts. The crude product is a grayish-white, porous substance with a fine-grained structure. Non-toxic; dust can irritate the eyes. Function: 1. Used as a sizing agent in the paper industry to enhance the water resistance and impermeability of paper ； 2. When dissolved in water, it causes the small particles and natural colloids present in the water to aggregate into larger flocs, thereby allowing them to be removed from the water; hence it is used as a coagulant in water supply and wastewater treatment ； 3. It is used as a clarifier for turbid water, as well as a precipitant, color fixative, filler, etc. Used in cosmetics as an antiperspirant raw material (astringent) ； 4. In the fire-fighting industry, it is used together with baking soda and foaming agents to form foam fire extinguishants ； 5. Analytical reagents, mordants, tanning agents, oil bleaching agents, wood preservatives ； 6. Stabilizers for pasteurization of albumin (including liquid or frozen whole eggs, egg whites, or egg yolks) ； 　7. Can be used as a raw material for manufacturing synthetic gems and high-quality ammonium alum, as well as other aluminum salts ； 8. In the fuel industry, it is used as a precipitant in the production of chrome yellow and lake dyes, At the same time serving as a color fixative and filler. Modified monocationic inorganic flocculants include, in addition to the commonly used polyaluminum and polyferric compounds, polyactive silica gels and their modified versions, such as polysilicoaluminum (ferrous) and polyphosphoaluminum (ferrous) compounds. The purpose of modification is to introduce certain highly charged ions in order to enhance the charge-neutralizing capacity, as well as to add hydroxyl groups, phosphate groups, etc. to improve the coordination and complexation ability, thereby altering the flocculation effect. The possible reasons for this are that certain anions or cations can change the morphological structure and distribution of the polymers, or there may be a synergistic effect between two or more polymers. Polysilicic acid flocculant (PSAA) is a new type of inorganic polymer flocculant that features simple preparation methods, readily available raw materials, and low cost. It possesses a stronger oil-removal capacity for treating produced water from heavy oil in oil fields, which gives it great potential for development and wide-ranging application prospects. The polyferric silicate sulfate (PFSS) flocculant shows that highly polymerized silicic acid, together with metal ions, can produce excellent coagulation effects. By introducing metal ions into polysilicic acid, a coagulant with an average molecular weight of up to 2×105 is obtained, which has the potential to partially replace organically synthesized polymer flocculants in water treatment. In polyphosphoric ferric chloride (PPFC), the high-valent PO43- anion has a strong affinity for Fe3+, exerting a significant influence on hydrolyzed solutions of Fe3+. It can participate in the complexation reactions of Fe3+ and act as a bridge between iron atoms, thereby forming polymeric complexes ； The electroneutralization, adsorption, and bridge-forming effects on negatively charged diatomite colloids in water are enhanced; meanwhile, the participation of PO43- increases the volume and density of flocs, thereby improving the flocculation effect. Polyaluminum chlorophosphate (PPAC) is also based on the strong polymerization-enhancing effect of phosphate groups on polyaluminum (PAC); an appropriate amount of phosphate is introduced into polyaluminum, and through this polymerization-enhancing action of the phosphate groups, PPAC gives rise to a new class of highly charged, phosphate-containing polynuclear intermediate complexes. Ferric polysilicate (PSF) is not only effective in treating water with low temperatures and low turbidity, but also exhibits significantly superior flocculation properties compared to ferric sulfate. It requires less dosage, can be used within a wider range of concentrations, results in the formation of flocs that are larger in size and easier to settle, and thus reduces the retention time of water samples within the treatment system. This improves the system’s processing capacity, with little effect on the pH value of the treated water. The modified polycationic inorganic flocculant, polyaluminum ferric sulfate chloride (PAFCS), exhibits better performance in drinking water and wastewater treatment compared to alum ； In oily wastewater and printing and dyeing wastewater, PAFCS performs better than PAC, and it also has a superior decolorization capacity ； The flocs have a high specific gravity, settle rapidly, are easy to filter, and yield a high water recovery rate ； Its raw materials are all derived from industrial waste residues, resulting in low costs, making it suitable for industrial water treatment. Aluminum-iron copolymer composite flocculants also fall into this category; their raw materials, aluminum chloride and iron chloride, are both inexpensive traditional inorganic flocculants that are readily available and require simple production processes, which facilitates their development and application. The copolymer of aluminum salts and iron salts is different from a mixture of the two salts; it is a flocculant that more effectively combines the advantages of PAC and FeCl3, thereby enhancing its turbidity-removing effect. Its effective iron-aluminum content (AL2O3+Fe2O3) is greater than 22%, and the product has strong hygroscopicity. Studies have shown that when the effective aluminum content of polyaluminum chloride (PAC) is higher than that of PAFCS in terms of effective aluminum and iron content, PAFCS yields better results in wastewater treatment compared to alum. In oily wastewater as well as in printing and dyeing wastewater, PAFCS performs better than PAC, and it also has a stronger decolorizing capacity. The flocs have a high specific gravity, rapid flocculation speed, are easy to filter, and yield a high water recovery rate. Their raw materials are industrial waste residues, resulting in low costs, making them suitable for wastewater treatment. Polyferric silicate flocculants are also among them; when used to treat domestic wastewater, their treatment efficiency and COD removal rate are superior to those of polyferric compounds. The turbidity removal rate exceeds 99%, the color removal rate is 65%–70%, and the COD removal rate reaches 70%. At the same time, they can remove most of the ammonia nitrogen and all of the phosphorus present in domestic wastewater. Aluminum-iron copolymer composite flocculants also belong to this category. Their raw materials, aluminum chloride and iron chloride, are both inexpensive traditional inorganic flocculants that are readily available and require simple production processes, making them suitable for development and utilization. The copolymer of aluminum salts and iron salts is different from a mixture of the two salts; it is a flocculant that more effectively combines the advantages of PAC and FeCL3, thereby enhancing its turbidity-removing effect. Among them, the effect of the content and morphological distribution of iron in the aluminum-iron copolymeric composite flocculant on its flocculation performance remains to be further studied. The pH value of the copolymer is determined by the hydrolysis capacities of PAC and FeCl3 solutions; the pH value of the resulting solution lies between those of the two parent solutions, depending on the relative amounts of aluminum salt and iron salt present. Other: Ferric poly sulfate is a cationic inorganic polymer flocculant that consists of multi-hydroxy, multi-nucleated complexes. It can mix rapidly with water in any proportion. It has a higher molecular weight than ordinary inorganic flocculants; when used for water treatment, it exhibits strong adsorption, flocculation, and coagulation properties. The resulting flocs are large and form quickly, they are not prone to breaking apart, and it has good re-coagulation capabilities. The water after precipitation filters quickly, and it allows for a wide range of pH values in the purified water. Polyaluminum chloride belongs to inorganic coagulants. Mainly drinking water treatment, municipal sewage treatment, and wastewater treatment from the papermaking and dyeing industries. It has a low price and a wide range of market applications. Polyaluminum ferric chloride is a new type of high-efficiency coagulant produced by combining ferrous ions or iron oxide with other iron-containing compounds. It is mainly used for drinking water and industrial wastewater treatment. Organic polymer flocculants – Edit: The advantages of organic flocculants are their cost-effectiveness and simplicity of use; however, they require large amounts to achieve good flocculation effects, and they have the disadvantages of high costs and strong corrosivity. Organic polymer flocculants are a new type of wastewater treatment agent that were developed only in the late 1960s. Compared to traditional flocculants, it can double the efficiency while being cheaper, which gives it a tendency to gradually become the mainstream agent. Together with the stable product quality, the production of organic polymer-based flocculants accounts for 30% to 60% of the total flocculant output. Certain natural polymeric organic substances, such as polysaccharides with many carboxyl groups and starches with many phosphate groups, possess flocculating properties. Introducing reactive groups into macromolecules through chemical methods can improve such properties; for example, by carrying out etherification reactions on a natural polysaccharide to introduce reactive groups such as carboxyl and amide groups, its flocculation ability is enhanced, which can accelerate the sedimentation of sugarcane juice. By grafting and copolymerizing natural polymers such as starch, cellulose, chitosan, etc. with acrylamide, the resulting polymers exhibit good flocculation properties, or possess certain special properties as well. Some products developed domestically are mainly used for wastewater treatment and sludge dewatering. Since most organic polymer flocculants, either in their original form or as a result of their hydrolysis or degradation, are toxic, and the acrylamide monomer used for their synthesis is also toxic and capable of damaging the human central nervous system, their application areas are limited. This has forced the development of flocculants that are inexpensive, practical, non-toxic, and highly effective. Types and classifications: There are many types of organic flocculants. They are all polymer organic compounds containing a large number of active groups, and can be mainly divided into three categories: 1. Those derived from natural polymer organic compounds, with their content of active groups increased through chemical treatment. 2. A series of polyacrylamide products synthesized using modern organic chemical methods. 3. It is made using natural raw materials and polyacrylamide grafting (or copolymerization). Organic polymer flocculants are divided into two main categories: natural polymers and synthetic polymers. Based on their chemical structure, they can be divided into the following 3 types: (1) Polyamine-type – low-molecular-weight cationic electrolytes ； (2) Quaternary ammonium type – exhibits a wide range of molecular weights and has high cationicity ； (3) Copolymers of acrylamide – with relatively high molecular weights, ranging from hundreds of thousands to several million or even tens of millions – are available in emulsive or powdered form; they are less convenient to use, but possess good flocculation properties. Based on the charge of the particles after dissociation due to different functional groups, they can be classified into three main categories: cationic, anionic, and non-ionic. Organic polymer flocculants can contain hydrophilic groups such as -COO-, -NH-, -SO3-, and -OH- in their macromolecules, and they come in various structures including linear and cyclic forms. Due to its numerous active groups and high molecular weight, it features low usage requirements, reduced sludge production, strong flocculation ability, easy separation of flocs, as well as excellent oil and suspended solids removal effects in the treatment of refinery wastewater. Polyacrylamide is the most widely used coagulant in water treatment in China. It is a synthetic polyacrylamide product series, mainly classified into anionic, cationic, non-ionic, and amphoteric types. Polyacrylamide, often abbreviated as PAM (it was also abbreviated as PHP in the past), refers to various types of PAM used in water treatment. Essentially, these are polymer products formed through a copolymerization reaction between acrylamide and sodium acrylate in specific proportions, and there is a range of such products available. Polyacrylamide can be classified into ultra-high molecular weight polyacrylamide, high molecular weight polyacrylamide, medium molecular weight polyacrylamide, and low molecular weight polyacrylamide based on their molecular weight. Ultra-high molecular weight polyacrylamide is primarily used in the third-phase oil recovery in oil fields. High molecular weight polyacrylamide is mainly used as a flocculant, medium molecular weight polyacrylamide is primarily used as a dry strength agent in paper, and low molecular weight polyacrylamide is mainly used as a dispersant. Polyacrylamide belongs to high-molecular polymers. Specialized in the treatment of various difficult-to-manage wastewater streams as well as sludge dewatering. (Cationic polyacrylamide is generally used for sludge dewatering) and is widely applied in the treatment of municipal wastewater as well as sludge from the papermaking and printing industries. The molecular formula of acrylamide is: CH2 = CH－CONH2. The molecular formula of sodium acrylate is: CH2 = CH－COONa. Non-ionic organic polymer flocculants – Non-ionic organic polymer flocculants are primarily polyacrylamide. It is obtained by the polymerization of acrylamide. Anionic organic polymer flocculants such as polymers like polyacrylic acid, sodium polyacrylate, calcium polyacrylate, and the alkali-hydrolyzed products of polyacrylamide. Copolymers of styrene sulfonate, lignosulfonate, acrylic acid, methacrylic acid, etc. Cationic organic polymer flocculants 2.4.1 Quaternized polyacrylamide Cationic forms of polyacrylamide are obtained by hydroxymethylation and quaternization of the -NH2 group; they can be classified into cationization of polyacrylamide and polymerization of cationized acrylamide. Polyacrylamide (PAM) first reacts with a formalin aqueous solution, resulting in the hydroxymethylation of the amide group; it then reacts with secondary amines to undergo alkanamidation, and finally reacts with acid salts or aminating agents to cause the tertiary amine to be quaternized. Under alkaline conditions, acrylamide first reacts with a formalin aqueous solution, then with dimethylamine; after cooling, salt is added for quaternization. The product is evaporated and concentrated, followed by filtration, to yield quaternized acrylamide monomer. Cationic derivatives of polyacrylamide are products that are typically obtained by copolymerizing acrylamide with cationic monomers. Amphiphilic polyacrylamide polymers are synthesized as amphiphilic polyacrylamide flocculants with carboxyl and ammonium groups, by adding an appropriate amount of formaldehyde and dimethylamine to partially hydrolyzed polyacrylamide via the Mannich reaction. Acrylamide-grafted copolymers utilize starch, which is inexpensive and readily available, and they themselves are polymer compounds featuring hydrophilic rigid chains. With these rigid chains as a backbone, flexible polyacrylamide side chains are attached to them. This hybrid network of rigid and flexible molecules not only retains the properties of native polyacrylamide but also possesses certain superior characteristics. Composite flocculants – Organic-inorganic composite flocculants dominate due to their variety of types and diverse properties. The mechanism of action is mainly related to synergy. Inorganic polymer components adsorb impurities and suspended particles, causing the formation of particles that gradually increase in size; whereas organic polymer components, through their own bridging effects and the active groups adsorbed on them, create a trapping effect that captures other impurity particles, causing them to sink as well. At the same time, the presence of inorganic salts neutralizes the surface charge of pollutants, facilitating the flocculation of organic polymers and **improving the flocculation effect**. Significant progress has been made in the production and application of inorganic polymer flocculants in our country. Research on polyaluminum chloride and polyferric sulfate, which are the most representative of such compounds, is among the best in the world. Microbial flocculants – Editor: The commercial production of microbial flocculants abroad began in the 1990s, owing to their lack of secondary pollution, ease of use, and promising application prospects. Microorganisms such as Rhodococcus erythropolis and the NOC-1 produced from them are currently the best microbial flocculants identified, possessing strong flocculation activity and being widely used in the treatment of livestock wastewater, expanded sludge, and colored wastewater. There are no reports on products of microbial flocculants in our country. Microbial flocculants mainly include those using microbial cell wall extracts, those using metabolic products of microbial cell walls, those using microbial cells directly, and those obtained through cloning technology. The flocculants produced by microorganisms are high-molecular compounds such as glycoproteins, mucopolysaccharides, proteins, cellulose, and DNA, with a relative molecular mass of over 105. Microbial flocculants are new types of water treatment agents that are safe, efficient, and capable of natural degradation; they are obtained through biotechnology by extracting and purifying them from microorganisms or their secretions. Since microbial flocculants can overcome the inherent defects of inorganic polymeric and synthetic organic polymeric flocculants, thereby enabling pollution-free discharge, research on microbial flocculants has become an important topic in the field of flocculants worldwide today. Researchers studying microbial flocculants have long discovered that certain microorganisms such as yeasts and bacteria exhibit cell flocculation, but this phenomenon has not received much attention; it has been used merely as a method for cell enrichment. In the past decade or so, cell flocculation technology has come to be widely used in continuous fermentation and product separation as a simple and cost-effective method for separating biological products. Microbial flocculants are a class of polymeric organic substances produced by microorganisms that possess flocculating properties. They mainly include glycoproteins, mucopolysaccharides, cellulose, and nucleic acids. In terms of its origin, it also belongs to natural organic polymer flocculants; therefore, it possesses all the advantages of natural organic polymer flocculants. At the same time, research on microbial flocculants has progressed from purification and modification to the use of biotechnology to cultivate and select superior strains in order to obtain highly effective flocculants at lower costs; as a result, its scope of research has extended beyond that of traditional natural organic polymer flocculants. Microorganisms with the ability to secrete flocculants are called flocculant-producing bacteria. The earliest flocculant-producing bacterium was isolated by Butterfield from activated sludge. In 1976, Nakamura J. et al. screened out 19 microorganisms with flocculation capabilities from various species of molds, bacteria, actinomycetes, yeasts, etc. Among them, the flocculant produced by Aspergillus souae AJ7002 exhibited the best effect. In 1985, Takagi H and others studied the flocculant PF101 produced by the microorganism Paecilomyces sp. l-1. PF101 exhibits excellent flocculation effects on Bacillus subtilis, Escherichia coli, brewer’s yeast, red blood cells, activated sludge, cellulose powder, activated carbon, diatomite, alumina, and others. In 1986, Kurane and others developed the microbial flocculant NOC-1 using Rhodococcus erythropolis; it exhibits excellent flocculation and decolorization effects on Escherichia coli, yeast, mud water, river water, fly ash water, activated carbon powder water, expanded sludge, pulp wastewater, and more. It is currently considered the best microbial flocculant discovered to date. The molecular weight, molecular structure and shape of the flocculant, as well as the functional groups it possesses, all affect its flocculating activity. Generally speaking, the higher the molecular weight, the greater the flocculation activity ； Linear molecules have high flocculation activity; the more branches or cross-links a molecule has, the worse its flocculation properties ； In the later stages of cultivation, the bacteria that produce flocculants have an increased hydrophobicity on their cell surfaces, which results in higher activity of the flocculants they produce. The surface structure and charge of colloidal ions in water also affect the flocculation effect. Some reports indicate that cations in water, particularly Ca2+ and Mg2+, can effectively reduce the negative charge on the surface of colloids, thereby facilitating the formation of \"bridges\". Furthermore, the presence of high concentrations of Ca2+ can also protect the flocculant from the action of degradation enzymes. Thanks to their advantages of high efficiency, safety, and environmental friendliness, microbial flocculants also hold great potential for application in fields such as pharmaceuticals, food processing, and the separation of biological products. Working principle and applications? Edit: Principle. The flocculation sedimentation method involves using inorganic flocculants such as aluminum sulfate, along with organic anionic flocculants like polyacrylammonium (PAM), to prepare aqueous solutions which are then added to wastewater. This results in the formation of a compressed double electric layer, causing the suspended particles in the wastewater to lose their stability. The colloidal particles then aggregate with each other, increasing in size and forming flocs or flocculated masses. Once the flocs reach a certain size, they separate from the aqueous phase under the influence of gravity and settle, thereby removing a large amount of suspended solids from the wastewater and achieving water treatment effects. To improve the separation efficiency, coagulants can be added in a timely and appropriate manner. The treated wastewater can basically meet the discharge standards in terms of color intensity, chromium content, and suspended solids levels, and can thus be discharged or used as reinjection water for artificial water flooding in oil extraction. Flocculants are the most widely used chemicals in wastewater treatment today, and the flocculation process is a crucial and essential step in wastewater treatment processes. Based on their chemical composition, they can be classified into inorganic salt flocculants, organic polymer flocculants, and microbial flocculants. Users can make a reasonable choice based on the different properties of the wastewater. The combination of flocculants with wastewater treatment equipment enhances the efficiency of wastewater treatment, effectively solving the challenges associated with it. The use of flocculants in wastewater treatment effectively increases the rate of wastewater treatment, resulting in significant improvements in its efficiency. Currently, this chemical is widely used in wastewater treatment across various industries, ensuring that the water quality after treatment by large-scale wastewater treatment facilities meets the specified discharge standards. It helps to prevent the deterioration of water pollution and supports the sustainable development of the ecological environment. Organic polymer flocculants are used in the treatment of refinery wastewater; by adding such flocculants, water and impurities can be separated quickly and fairly thoroughly. Functions of microbial flocculants: Compared with organic polymer flocculants, microbial flocculants feature a wide range of flocculation capabilities, high activity, safety and non-toxicity, and no environmental pollution. Moreover, they have specific application conditions and broad-spectrum flocculation activity, which enables their widespread use in water supply and wastewater treatment. ⑴ Treatment of high-concentration organic wastewater: High-concentration organic wastewater mainly includes wastewater from livestock farming as well as wastewater from various food and agricultural industries. Such wastewater undergoes pre-treatment processes such as flocculation before biochemical treatment. Microbial flocculants have a worse flocculation effect than SPA; it can be inferred that if microbial flocculants are mixed with large amounts of SPA in advance, the pretreatment efficiency of amino acid wastewater can be further improved, and the total amount of chemicals required for treatment can be significantly reduced. ⑵ Dyeing and printing wastewater, which is characterized by its light color and complex composition, contains various substances such as dyes, sizing agents, auxiliaries, fibers, resins, waxes, and organic salts; it remains one of the various challenges associated with the improper management of industrial wastewater in the country. Its easy-to-treat aspect is that the COD level is not high, and the B/C ratio is relatively low, resulting in poor treatability ； Secondly, the chromaticity is high and the overall group composition is complex. The key to treating printing and dyeing wastewater lies in decolorization. Among various treatment methods, the flocculation method is widely used due to its low investment cost, small space requirement for equipment, high treatment efficiency, and high decolorization rate. Compared to micro-debris flocculants, polyferric flocculants not only possess excellent flocculation and sedimentation properties but also exhibit good color removal effects; they offer advantages in printing and dyeing wastewater treatment that normal flocculants do not have. ⑶ Solving high-dilution organic suspended wastewater: High-dilution organic suspended wastewater is not a type of wastewater that cannot be treated through maturation processes; traditional agricultural practices employ chemical flocculation and treatment methods. In addition to being used for treating water samples such as kaolin slurry, mud slurry, and fly ash, these micro-flocculants can also be employed outside of experiments for flocculating and treating wastewater from ceramic factories, as well as wastewater from glaze production and clay preparation processes. ⑷ The efficiency of activated sludge in dealing with suspended solids often declines due to a deterioration in the sludge’s flocculation properties. By adding micro-flocculants to the activated sludge, it is possible to rapidly reduce the sludge volume index, prevent sludge from aggregating, and eliminate sludge shrinkage, thereby restoring the flocculation capacity of the activated sludge and improving the efficiency of the entire treatment system. Xiti is a type of flocculant of a new design; these micro-flocculants hold great potential for application, and although they are not yet widely used in the treatment of low-concentration inorganic wastewater, the decolorization of dye wastewater, and the treatment of activated sludge among other waste treatment processes, they have shown strong viability. Micro-dead matter flocculant: no. 1. Urban sewage is treated using an efficient mixed microbial community isolated from municipal domestic wastewater, which possesses flocculation and degradation capabilities; this enables a 100% removal rate of COD and BOD in the sewage. 2. Construction material wastewater contains a high amount of clay particles, while the latter type of wastewater, in addition to clay particles, also includes a significant quantity of glaze. 5 minutes after the addition of NOC-1, the turbidity of the embryo wastewater decreased from 1.4 to 0.043 ； The turbidity of the glaze wastewater decreased from 17.2 to 0.35 ； The turbidity removal rates were 96.6% and 97.9%, respectively, resulting in an almost transparent supernatant. Treating tile factory wastewater with the flocculant produced by Rhodococcus erythropolis yielded a supernatant that was almost transparent. 3 Other applications: Due to their safe and non-toxic properties, microbial flocculants are increasingly being used in the treatment of food wastewater, achieving satisfactory results. In addition, microbial flocculants can also be widely used in the treatment of various types of wastewater, including municipal sewage, hospital wastewater, petrochemical wastewater, papermaking waste liquid, and pharmaceutical wastewater. High efficiency and the absence of residual substances that could cause secondary pollution represent an important direction for future research and development in flocculants. Safe, non-toxic, and efficient microbial flocculants are likely to replace traditional flocculants. Guidelines for selection: When choosing a flocculant for wastewater treatment, it is necessary to consider the characteristics of the wastewater from the specific industry, as well as at which stage the flocculant should be added and what purpose it will serve. When selecting inorganic flocculants, factors such as the composition of the wastewater and its pH level need to be taken into consideration, in order to choose the most suitable one (iron salts, aluminum salts or iron-aluminum salts, silicon-aluminum salts, silicon-iron salts, etc.). When selecting organic flocculants (such as polyacrylamide PAM), the key consideration is whether to use anionic polyacrylamide, cationic polyacrylamide, or non-ionic polyacrylamide. Anionic polyacrylamides are generally classified into weakly anionic, moderately anionic, and strongly anionic types depending on their degree of hydrolysis. The selection of cations is generally used in sludge dewatering. It is important to choose the right type of cationic polyacrylamide; urban sewage treatment plants typically use medium-strength cationic polyacrylamide, while paper and printing industries opt for weakly cationic polyacrylamides for sludge dewatering. Strongly cationic polyacrylamides are usually chosen for pharmaceutical wastewater treatment, and so on. Each type of wastewater has its own unique characteristics. Non-ionic polyacrylamide is primarily used in weakly acidic conditions, and printing and dyeing factories make extensive use of non-ionic PAM. The selection of all these flocculants must be determined through testing. In these tests, the approximate dosage is first determined, the speed of flocculation and sedimentation is observed, the treatment costs are calculated, and then an economical and suitable flocculant is chosen. The classification of flocculants is analyzed based on their charge type, charge density, molecular weight, and molecular structure, providing an overview of them. This helps to gain a clearer understanding of the applications of various flocculants, as well as offering a more precise insight into the selection of flocculants for wastewater treatment. 1. Charge type of flocculants ； Select the charge of the flocculant based on the type of particles in the wastewater. Generally speaking, the selection of the charge on the flocculant should follow the following principles ； Negative-charged flocculants are used to capture inorganic particles, while positive-charged flocculants are used to capture organic particles. The type of charge carried by a flocculant can usually be determined with accuracy only through experimental methods. 2. Charge distribution density (degree of ionization) of the flocculant: This refers to the amount of positive or negative charge that a flocculant must possess in order to achieve the best flocculation results with the smallest possible amount of flocculant used. The charge distribution density is related to the type of sludge; for municipal sludge, it is generally a function of the organic content in the sludge, and the organic content is typically associated with the volatile matter content. The higher the volatile matter content, the greater the charge requirement for the flocculants used. 3. Molecular weight: The choice of molecular weight depends on the type of equipment used for the dehydration process; it also indicates the length of the polymer chains. For centrifugal dewatering equipment: the higher the molecular weight of the polymer, the better, as the flocs are subjected to high shear forces during the centrifugal dewatering process. For filter-type dewatering equipment: selecting a flocculant with a molecular weight in the range of low to medium will meet the requirements and also ensure good water removal performance. 4. Molecular structure: The choice of the molecular structure for flocculants depends on the desired dewatering performance. The molecular structures of cationic flocculants can be classified into linear structures, branched structures, and cross-linked network structures. From these aspects, it is easy to see that there are clear patterns in the selection of flocculants. By paying close attention to these patterns and drawing conclusions from daily applications, we can determine that each type of wastewater has its specific flocculant or combination of flocculants that can be used for flocculation or dewatering in wastewater treatment. Precautions: The changes in flocculation properties that occur under adverse conditions due to the flocculant are collectively referred to as degradation. This is manifested by a decrease in molecular weight, a reduction in solution viscosity, and worsened or even lost flocculation performance. There are many factors that may produce this effect. In this regard, high-molecular-weight pam is a rather \"delicate\" substance. Moreover, the higher the molecular weight of pam, the more likely such changes occur, and it becomes more sensitive to the relevant factors. Great attention must be paid to this issue; otherwise, no matter how good the flocculant is, it will not yield good results. Modern polyacrylamide products have a very high molecular weight, which is the basis for their excellent flocculation properties. However, the macromolecules of such flocculants are prone to being damaged by external factors, resulting in a **decline in their performance**. Careful attention must be paid to preventing this issue during the preparation and use of flocculants. The main factors that lead to a decrease in the viscosity and flocculation efficiency of the pam solution are: 1. Mechanical effects: High-speed stirring or applying strong mechanical shear in the solution can cause the large molecules to break apart. If the pam solution is stirred in a centrifugal pump for a few seconds, its molecular weight decreases by up to 75%. Using high-speed stirring for dissolution or high-speed equipment for transportation will significantly reduce its molecular weight and flocculation properties. 2. Rust and iron compounds: Adding a very small amount (such as 2 mg/l) of iron compounds (such as FeCl3) to the Pam solution, or a small amount of rust powder, and stirring gently to disperse it, significantly reduces the viscosity and flocculation properties of the Pam solution. When the pam solution was placed in rusty ironware, the viscosity decreased by 78% after 4 hours, and the flocculation efficiency **decreased**. 3. Effect of high temperature: Pam macromolecules are very sensitive to high temperatures; for example, a 0.1% pam solution, when left at 80°C for 4 hours, sees its molecular weight decrease from 21 million to 7.6 million, and it also drops to 16.9 million when kept at 50°C ； PAM with a molecular weight of 10.5 million had its molecular weight reduced to 3.3 million after being left at 80°C for 4 hours. At 30°C, the molecular weight decreases very slowly. If the original molecular weight of pam is very low, such as 3.7 million, degradation upon heating is minimal. 4. Effect of co-existing impurities: The presence of suspended impurities in the pam solution can reduce its viscosity. Inorganic ions, especially high-valent ions, also have a significant impact. If the viscosity of a pam solution is 191 centipoise, adding NaCl containing 100 mg/L of Na+ reduces the solution’s viscosity to 140 centipoise, while adding CaCl2 containing 100 mg/L of Ca2+ reduces the viscosity to 30 centipoise. 5. Others: Ultraviolet radiation causes rapid degradation of Pam; 4 hours of intense exposure can reduce the molecular weight of Pam from 18 million to 10 million, and the presence of oxidants in the solution also accelerates this degradation. The degradation of Pam occurs through a free radical chain reaction; any factor that can generate free radicals will accelerate the degradation of Pam. The reaction between oxygen and iron can produce free radicals; the same is true for ultraviolet light, so it’s important to avoid them both. The decline in the performance of the Pam solution is partly due to changes in the morphology of the macromolecules: from linear, extended chain shapes to contracted, curled spherical shapes. PAM molecules contain a large number of negatively charged groups, which repel each other and cause the macromolecules to assume an extended shape. The molecules are long, with their active groups fully exposed, enabling them to act as bridges for connection; as a result, they exhibit good flocculation properties. However, if there are many cations in the Pam solution, they form a double layer around the negatively charged groups of the macromolecules, which reduces the repulsive forces between these negative groups and causes the Pam macromolecules to adopt a coiled structure. The higher the ion concentration, the greater this effect. Bivalent ions such as Ca2+ are not only strongly adsorbed by negative charge groups, but they may also bridge two such groups together, further enhancing the shrinkage of macromolecules. This not only leads to a decrease in the viscosity of the solution (the viscosity of solutions containing spherical macromolecules is much lower than that of those containing linear molecules), but it also reduces the effective reactivity of the carboxyl groups in the Pam molecules, resulting in a significant decline in their flocculation properties. The usage method of PAC and the optimal settings are as follows: 1. First, conduct laboratory analysis; if the potential at the solid-liquid interface of the suspended solids is negative (which is usually the case), the PAC+CPAM approach can be used. 2 Determine the dosage of PAC: It is also necessary to conduct a dosage test in the laboratory first to determine the dosage of PAC when used alone as well as the curve showing its turbidity removal efficiency. 3 If the optimal dosage of PAC when used alone is A, then the actual dosage can be set at 1/4 to 1/3 of that value, leaving the remaining task to be carried out by CPAM. 4 The laboratory determines the addition ratio of PAC to CPAM: that is, when the amount of PAC used is 1/3 of value A, it is determined how much CPAM is needed to optimize the coagulation effect provided by PAC. Through experiments, the addition ratio of PAC to CPAM was determined. The above steps will enable wastewater treatment companies to achieve the best results at the lowest flocculation costs. For example: if the best result is achieved when 20 KG of PAC is used for 1000 cubic meters of water, then 6 KG of PAC can actually be used to achieve coagulation. And 200 grams of CPAM (usually 1/30 of the amount of PAC used) is employed to carry out the task of connecting the tiny flocs that would otherwise require 14 KGPAC to accomplish. In this cooperation, PAC and CPAM each carried out their most effective tasks, achieving the best results. The above treatment methods are also universally recognized as an efficient and low-cost combination. Factors affecting flocculation efficiency? Editor: There are various factors that influence flocculation efficiency, including the type, concentration, and dosage of the flocculant, the mixing conditions during coagulation treatment, pH value, temperature, and its variations. Different strategies should be adopted based on specific circumstances. 1. Types and amounts of flocculants: Different flocculants should be selected for different types of wastewater. The amount of flocculant used has a significant impact on the effectiveness of flocculation; both excessive and insufficient amounts can affect the dispersion and stability of sol particle, so the optimal dosage should be determined through experiments. 2. Influence of mixing and reaction time: After adding a certain amount of flocculant to wastewater, it is first necessary to ensure that the flocculant spreads rapidly and evenly throughout the water. After the flocculant is fully dissolved, the colloids formed come into contact with the existing colloids and suspended particles in the water, resulting in the formation of numerous tiny floc particles; this process is also known as mixing. The mixing process requires intense turbulence in the water flow to ensure thorough mixing of the chemical with the water within a short period of time; the mixing time generally ranges from a few seconds to 2 minutes. 3. Influence of pH value and alkalinity: The pH value has a significant impact on the use of flocculants; therefore, when carrying out flocculation treatment on wastewater, it is essential to pay close attention to its optimal pH range. Organic polymer flocculants are not very sensitive to pH values, but low pH levels have a significant impact on the flocculation efficiency of these agents. Inorganic flocculants are quite sensitive to the pH value of wastewater; since the hydrolysis reaction of these flocculants continuously produces hydrogen ions, it is necessary to ensure that this hydrolysis reaction proceeds adequately. 4. Effect of temperature: Water temperature also has an impact on the flocculation effect. The hydrolysis reaction of inorganic flocculants is an endothermic process; low water temperatures hinder the hydrolysis of these flocculants. The viscosity of water is also related to its temperature – when the temperature is low, the viscosity of water increases, which reduces the brownian motion of water molecules. This makes it difficult to destabilize and flocculate the colloidal pollutants present in the water, thus making it hard for flocculates to form. Therefore, more flocculant is used in winter than in summer. An increase in temperature facilitates collisions between colloids, leading to aggregation; however, when the temperature exceeds 90 degrees Celsius, the flocculant tends to age or decompose, producing insoluble substances that instead reduce the flocculation effect. Production process? Edit (1) Flocculant production process – Hydrolysis method. Compared to the copolymerization method, the products prepared by the conventional hydrolysis method have a low water solubility of the dandruff-fighting agent (HD), below 30%. Theoretically, products with an HD level above 70% should be produced using the copolymerization method; this approach has certain requirements regarding hydrolysis temperature and conditions, and large-molecule degradation tends to occur during the hydrolysis process. Ji Lanying and others from Tianjin University conducted research on the hydrolysis method using hydrolysis agents such as NaOH and Na2CO3, and found that NaOH not only accelerates hydrolysis but also enhances it. If a low degree of hydrolysis is desired (

Thank you to the moderator for the answer; it was very helpful!

I would like to ask everyone: what are the components of the additives, dispersants, and flocculants added during gasification? What are the technical requirements and specifications for these additive components!

The temperature of the flocculant should not exceed 60°C, and the temperature of the dispersant should be below 350°C.

For a three-stage flash system, the temperature of the black water flowing from the true flash tank to the clarification tank should be around 78 degrees.

For a three-stage flash system, the temperature of the black water flowing from the true flash tank to the clarification tank should be around 78 degrees.