Development of spray dryer for production of powdered synthetic detergents

Contents

Introduction

1. Main materials and substances used for SMS production

2. Process Description

3. Patent search

4. Technological diagrams of production of powdered synthetic detergents by tower method

4.1. Process diagram of the unit with capacity of 30 thousand tons SMS per year

4.2. Process diagram of the plant with capacity of 60 thousand tons SMS per year

4.3. Process diagram of 100 thousand t unit SMS per year

5. Device and principle of operation of the developed spray dryer design

6. Set calculation

6.1. Dryer material balance

6.2. Heat balance of dryer

6.3. Approximate calculation of camera dimensions

6.4. Calculation of scraper drive

Conclusion

List of sources used

Introduction.

The simplest detergent was obtained in the Middle East more than 5,000 years ago. Most likely, it was discovered by pure chance when meat was fried over the bone, and fat was stack on ash with alkaline properties. Having taken up a handful of this simplest soap, an ancient man found that it easily dissolves in water and washes away with mud. At first, it was used mainly for washing and treating ulcers and wounds. And only from the first century C.E. did man wash with soap.

Soap production has a long history, but the first synthetic detergent appeared only in 1916. The invention of the German chemist Fritz Ponter was intended for industrial use, household synthetic detergents, more or less harmless to the hands, began to be produced in 1935. Since then, a number of synthetic detergents (CMC) have been developed for narrow purposes, and their production has become an important branch of the chemical industry.

Any detergent is a chemical solution of complex composition, therefore it is a chemical pollutant capable of causing acute poisoning, chronic diseases, as well as having carcinogenic and mutagenic effects. The synthetic detergent is based on surfactants - various salts of sulfonic acids or ethers of polyethylene glycols. There are also various detergent aids, stain removal enzymes and flavors.

Synthetic detergents have the following advantages:

1. SMS production is based on a cheap raw material base - oil and gas processing products. Calculations show that the cost of producing SMS is no more than 6570% of the cost of producing 47% of household soap.

2. A broad programme for the production of synthetic detergents makes it possible to release a large amount of food fats.

3. Synthetic detergents do not interact with hard water salts or, when reacted, produce compounds that are easily removed from the fabric.

4. Many of the SMS wash equally well in soft, hard, and some even in seawater. The CMC has a detergent effect not only in hot water but also in relatively low temperature water, which is very important when washing chemical fiber articles.

5. Synthetic detergents, depending on their composition, can wash fabrics well not only in alkaline medium, but also in neutral and acidic medium.

Formulations of modern CMC are complex mixtures of various substances. The main component of CMC is organic surfactants with wetting, emulsifying, peptizing and foaming properties. The combination of these properties determines their detergent effect. To enhance the detergent effect of surfactants, alkaline and neutral electrolytes, alkylolamides, carboxymethylcellulose, etc. are added to the composition of synthetic detergents. Whitening agents (peroxides, optical bleachers) are useful additives.

2. Process description.

The CMC is released in the form of a powder, liquid or paste. The preparation technique consists in formulation, mixing and dissolving all components of the formulation. Drying is used to produce powdered agents. Next is the packaging and packaging of the finished product.

Preparation of composition consists in mixing of surfactants with necessary additives. In order to reduce the evaporation costs of water, the most concentrated compositions (up to 5060% dry matter), which are actually suspensions, are prepared for powdered agents. The compositions are then filtered and passed through a colloidal mill to give uniformity. Drying consists in spraying the solution in the drying tower at a pressure of up to 50 atm and a temperature of 250350 C. In this method, powders are obtained in granular form. The main amount of powdered SMS is produced by a high-temperature spray drying method, which provides a granulated product of high quality.

Liquid and paste-like detergents are better soluble in water, easy to dose, their production is less expensive, since the drying process does not fall, but the persistence of such agents is lower. Paste-like agents contain up to 40% water. They can include almost all additives, with the exception of non-persistent chemical bleachers.

The main components of the CMC composition are alkyl sulfates, alkyl sulfonates and alkyl aryl sulfonates.

Alkyl sulfates are sodium salts of sulfoesters of higher fatty alcohols. Alkyl sulphates are obtained by sulphating fatty alcohols followed by neutralization of the obtained sulphone product.

Fatty alcohols are prepared by various methods:

1) fatty acid hydrogenation method;

2) method of direct oxidation of paraffinic hydrocarbons in the presence of boric acid;

3) sulfonation of fatty alcohols.

Synthetic powders are produced on the basis of primary alkyl sulphates, liquid synthetic detergents are produced on the basis of secondary ones.

Alkyl sulfonates are sodium salts of fatty sulfonic acids containing 1218 carbon atoms in the chain. The raw material for producing alkylsulfonates is natural and synthetic hydrocarbons containing 1422 carbon atoms (fractions of straight-run petroleum kerosene or hydrogenated syntin boiling in the range of 240300 C).

Alkylsulfonates can be prepared by two methods: sulfochlorination or sulfooxidation of aliphatic hydrocarbons. Sulfochlorination is carried out when gaseous sulfur anhydride and chlorine are acting on hydrocarbons. The reaction is accelerated by catalysts such as peroxides. For the reaction to proceed successfully, it is necessary to irradiate the reaction mixture with shortwave light. Treatment with caustic alkali (1520% solution) converts the resulting sulfochlorides to alkyl sulfonates. The resulting finished product is called "Sulfonate," it is used to prepare synthetic detergents such as "Astra," "News," etc. The technology for producing alkyl sulfonates is relatively simple, characterized by low capital costs, and the raw material base is practically not limited.

Alkylaryl sulfonates are sodium salts of alkylaryl sulfonic acids, are the most common detergents. In our country, alkyl aryl sulfonates are produced mainly in the form of alkylbenzenesulfonates (sulfonols).

Sulfonol production consists of the following steps:

a) purification of kerosene from aromatic hydrocarbons by extraction of the latter with diethylene glycol;

b) photochemical chlorination of purified kerosene;

c) alkylating benzene with chlorinated kerosene in the presence of an anhydrous AlCl3 catalyst;

d) sulfonation of alkylbenzene is carried out with a solution of sulfuric anhydride SO3 in liquid sulfuric anhydride SO3 at a reduced temperature (10 C), since the sulfonation process proceeds with high heat release;

e) neutralizing the obtained alkylbenzene sulfonic acids with caustic soda solution (20% solution). Neutralization temperature shall not exceed 45550 С;

and (e) separating the unsulphable solutions and evaporating the aqueous sulfonol solutions.

The currently available chlorine sulfonol in the form of a 30% solution (by active substance) is well established for the production of synthetic detergent powders.

4. Technological diagrams of production of powdered synthetic detergents by tower method.

The technology of production of granular powdered SMS by the tower method - spray drying of the composition - allows to obtain a finished product with high quality characteristics and good consumer properties. Powders have good looseness, do not dust, quickly dissolve in water during washing, have a uniform composition and uniform distribution of all components in the granules of the finished product. The production of powdered SMS using this technology is the most common in the world and in our country. Let us consider the main production schemes of powder-like SMS by spray drying method, which differ from each other in the design, volume and layout of reactors - mixers, the principle of operation and the device of feedstock dispensers and systems for automatic control of the dosing process, productivity of the finished product and other features.

Conclusion.

In this course project, a spray dryer of the nozzle type was developed and designed. During the calculations, the overall dimensions of the dryer were obtained and the type size was chosen: Dk = 1 m - the diameter of the drying chamber and H = 2 m - the height of the cylindrical part of the chamber. Size - 1 - SRF-1.0/1.6 VK.

The required power for driving the scraper mechanism was calculated:

N = 0.017 kW = 0.17 W. According to this power, a reduction motor and a conical gear with the necessary gear ratio were selected to transmit torque from the reduction motor to the shaft of the scraper mechanism :

MPO2M1028,20,75/50 motor reducer;

• output shaft speed n = 50 min-1;

• output shaft power N = 0.75 kW.

The production of powdered CMCs requires significant costs of thermal and electrical energy, as well as high costs of raw materials, water and other materials. Therefore, saving energy and raw materials in CMC plants is the most important task facing workers, ITR and employees. The reduction of fuel gas, electrical and thermal energy costs can be achieved by reducing the water content of the CMC composition supplied for drying; reducing the temperature of the waste heat agent after the drying tower; improvement of the heat agent introduction unit into the drying tower and its uniform distribution along the section and height of the tower; recovery of waste hot gases; insulation of equipment, pipelines, steam pipelines; feeding a portion of sodium tripolyphosphate into the mixing drum of the thermally stable additive injection unit; preliminary hydration of sodium tripolyphosphate before it enters the reactor mixer; using more efficient process equipment for preparing a low-water composition; application of raw materials with optimal physical and mechanical properties; due to the widespread use of aero lifts and pneumatic transport at CMC plants (instead of mechanical transportation of bulk raw materials and CMC powder); using effective, minimally energy-intensive homogenizers of the CMC composition (including homogenizers of the electromagnetic field with ferromagnetic particles); introduction of new types of equipment and lines of automatic process control using television and computer equipment; use of equipment, fittings, etc. made of corrosion resistant materials; replacement of obsolete heating and ventilation equipment; recovery of heat of discharged steam; reduction of production wastes; computer monitoring of power consumption.