General Chemical Engineering

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I. FURMER,V. ZAITSEV

General Chemical Engineering

GENE HAL CHEMICAL ENGINEERING

II. 3. (PypMep, B. H. 3aHn,eB

OBmAH XHMHHECKAH TEXHOJIOTHH MsA^TejiBCTBo «BbicmaH mKojia» MocKBa

I.E. FURMER AND V. N. ZAITSEV

GENERAL CHEMICAL ENGINEERING Translated from the Russian by Yu. N. VERESHCHAGIN

MIR Publishers Moscow

First published 1985 Revised from the 1984 Russian edition

Ha aneAuucKOM siamne

© HaffaTejibCTBo «Bbicmafl mKOjia», 1984 © English translation, Mir Publishers, 1985

CONTENTS

Introduction

..................................................................................

9

Chapter 1. Technical and Economic Indices of Chemical Tech­ nological Processes.......................................................

11

Chapter 2. Raw Materials and Energy for the Chemical Industry

17

2.1 2.2 2.3 2.4

Raw Materials for the Chemical In d u s try .................... Preparation of Raw Materials forProcessing . . . . Water for the Chemical In d u s try ............................... Energy for the Chemical In d u s try ...............................

17 27 36 41

Chapter 3. Basic Regularities of Chemical Technological Pro­ cesses ..........................................................................

47

3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8

The Concept of a Chemical Technological Process Classification of Chemical R eactio n s........................... Chemical Equilibrium in Technological Processes . . The Rate of a Chemical Technological Process . . . Choosing the Optimal Technological Conditions . . . Heterogeneous S y s te m s ................................................... Catalytic P ro c e s se s .......................................................... Material and Energy B alan ces.......................................

47 50 53 60 67 68 77 84

Chapter 4. Typical Methods for the Organization of Technological P ro ce sse s......................................................................

88

4.1 4.2 4.3 4.4 4.5

Flow Diagrams of ChemicalTechnological Processes Technological L in k s .......................................................... Energy Flow D iagram s.................................................. Batch and Continuous Processes................................... The Direction of F lo w s ...................................................

Chapter 5. Environmental Protection

91 93 96 98 99

......................................

101

5.1 Basie Trends in Environmental P ro te c tio n ................ 5.2 Methods for Purifying Gas E x h a u sts........................... 5.3 Sewage Treatment M ethods...........................................

103 105 HO

6

Contents

Chapter 6. Manufacture of Sulphuric A c id ............................... 6.1 6.2 6.3 6.4 6.5 6.6

Properties and Uses of Sulphuric A c id .............. 114 Raw Materials for the Manufacture of Sulphuric Acid Manufacture of Sulphur D io x id e.......................... 118 Conversion of Sulphur Dioxide into Sulphuric Acid Concentration of Sulphuric A c id .......................... 129 Materials Used to Manufacture the Apparatus for Sul­ phuric Acid P ro d u ctio n .......................................... 130 6.7 Storage and Transportation of Sulphuric Acid. . . . . 6.8 Perspectives in the Development of Sulphuric Acid Production ...................................................................... Chapter 7* Manufacture of Ammonia .

• •

114 116 122

130 130 132

7.1 Nitrogen Compounds and Their Importance for the National E c o n o m y ........................................................... 132 134 7.2 Methods for Fixing Atmospheric N itro g e n ................ 7.3 Manufacture of Nitrogen from A i r ............................... 137 7.4 Manufacture of H ydrogen............................................... 138 7.5 Gas P u rific a tio n ............................................................... 141 7.6 Ammonia S y n th esis........................................................... 143 7.7 Grades of Ammonia, Its Transportation and Storage 151 Chapter 8. Manufacture of Nitric A c id ....................................... 8.1 8.2 8.3 8.4

153

Properties and Grades of Nitric A c id ............................ Manufacture of Weak Nitric A c id ................................ Manufacture of Concentrated Nitric A c id .................... Storage and Transportation of Nitric Acid . . . . .

153 154 164 166

Chapter 9. Manufacture^ of Calcined S o d a ...................................

167

9.1 9.2 9.3 9.4

The Importance of Soda for the National Economy . . The Ammonia Process for Manufacturing Calcined Soda Manufacture of Sodium Bicarbonate . . . . . . . . Basic Trends in the Development of Soda Production

167 168 177 178

Chapter 10. Manufacture of Sodium Hydroxide, Chlorine, and Hydrochloric A c i d ...................................................

179

10.1 Chemical Processes for ProducingSodium Hydroxide 10.2 The Electrochemical Process for Producing Chlorine, Sodium Hydroxide and H ydrogen............................ 10.3 Manufacture of Hydrochloric A c id ...............................

180 181 189

Contents

Chapter 11. Manufacture of MineralFertilizers and Pesticides 11.1 11.2 11.3 11.4 11.5 11.6 11.7

Classification of Fertilizers#........................................... Phosphate F ertiliz ers....................................................... Nitrogen F e r t i l iz e r s ....................................................... Potash F e r tiliz e r s ........................................................... Compound Fertilizers ................................................... Microfertilizers ............................................................... Pesticides ......................................................................

Chapter 12. Chemical Processing of Solid F u e ls .................. 12.1 12.2 12.3 12.4 12.5

Classification of F u e l s ................................................... The Composition of Solid F u e ls ................................... Coal Coking .................................................................. Fuel Gasification ........................................................... Wood Processing ...........................................................

Chapter 13. Processing Liquid Fuels (Petroleum and Petroleum Products) .................................................................. 13.1 13.2 13.3 13.4 13.5

197 199 201 210 215 217 219 220 223 223 224 225 234 237

241

The Composition and Properties of Petroleum . . . Products from Petroleum P rocessing............................ Petroleum Processing ................................................... The Purification of Petroleum P ro d u c ts .................... The Processing of G a se s...............................................

242 244 247 257 259

Chapter 14. Technology of Basic Organic Synthesis....................

260

14.1 Products and Raw Materials for Basic Organic Syn­ thesis .............................................................................. 14.2 Dehydrogenation of H ydrocarbons............................... 14.3 Hydrogenation Processes............................................... 14.4 Hydration of H ydrocarbons....................................... 14.5 Oxidation P ro c e s s e s ....................................................... 14.6 The Halogenation of Hydrocarbons........................... 14.7 Other Methods for Manufacturing the Products of Basic Organic S y n th esis.......................................

260 262 271 273 279 286

Chapter 15. High-molecular Compounds............................... 15.1 General Information on High-molecular Compounds 15.2 Methods of Synthesis of P o ly m ers............................... Chapter 16. The Technology of Plastics...............................

289 291 291 296 300

16.1 Polymerization Resin-based P la s tic s ........................ 302 16.2 Polycondensation Resin-based P la s tic s ..............................310

8

Contents

16.3 Esters of Cellulose and Ester-based Plastics . . . . 16.4 Manufacture of Articles from P la s tic s ........................

315 315

Chapter 17. Manufacture of Chemical F ibres...........................

319

17.1 Processes for Manufacturing F ib r e s ............................ 17.2 Manufacture of Artificial F ib r e s ............................... 17.3 Manufacture of Synthetic F ib r e s ..............................

320 323 324

Chapter 18. The Technology ofRubber andVulcanized Rubber 18.1 Natural R u b b e r............................................................... 18.2 Synthetic R u b b e rs........................................................... 18.3 Manufacture of Vulcanized R u b b e r........................

327 328 329 333

INTRODUCTION

“Chemistry is broadly expanding its impact on human life. Its achievements can be observed everywhere.” Thesewords were spoken by the Russian scientist M. Lomonosov more than two hundred years ago. In modern times, they have proven even more justifiable than at the time of M. Lomonosov, since in recent years chemistry has penetrat­ ed into all spheres of industry, agriculture and daily life. Plastics, rubbers, paint and varnish coatings have been widely employed in the engineering industry. Engineering achievements would have been impossible without the arti­ ficial materials supplied by the chemical industry. Chemical materials have been introduced into the construction indus­ try, which had previously not used synthetic materials. Chemical products are of great importance for the intensi­ fication of agriculture. Fertilizers give nutrients to plants, and pesticides protect plants against pests and diseases. Fabrics, clothes, footwear, knitwear, artificial furs, leather, domestic appliances, and household articles are all provided by the chemical industry. Public health uses chemical products, such as drugs, vi­ tamins, and surgical materials, which are powerful helps in the struggle for human health. Chemistry has been so widely and fruitfully introduced into other industries that a modern economy cannot rapidly develop without growth in the chemical industry. Engineering is a science on methods and facilities for massscale processing of raw materials in consumer goods and means of production. There exist manufacturing and chemical engineering. Manufacturing engineering examines processes such as the processing of raw materials that do not generally bring about any change in the composition or the internal struc­ ture of the starting substance. For example, furniture is.

10

Introduction

made from wood, machines and equipment are manufac­ tured from metals, yarn and then fabrics are produced from •cotton, flax, and wool. Chemical engineering envisages chemical processing of raw materials when the composition, structure, and properties of the products obtained are not identical with those of the starting materials. For example, as a result of chemical pro­ cessing, plastics, synthetic rubbers and synthetic fibres are manufactured from natural gas; fibres, acetic acid, and methanol, from wood; dyes, pharmaceuticals, and other products, from coal. In a number of cases it is difficult to define the borderline between manufacturing and chemical engineering, since a •change in the shape and external appearance of materials may sometimes be accompanied by chemical reactions. And, vice versa, chemical processes that bring about a change in the composition of substances are accompanied by mechanical processes. Modern chemical enterprises are industrial complexes at which complex processes are being carried out. High-skilled workers are required to run them. At the present time, there are tens of thousands of prod­ ucts manufactured by chemical and related industries. It is not feasible to acquaint students with the manufacture of each product. It is essential therefore that every student should be provided with information on the regularities inherent in chemical processes and on the use of these regularities to apply these processes in practice. Due to this fact, the course in general chemical engi­ neering is acquiring a special importance in the training of industrial workers. The authors of this book deal with the theoretical fundamentals of chemical processes in a form -comprehensible to students of vocational training schools,; and show their application by giving specific examples in Ahe manufacture of major chemical products.

Chapter 1 TECHNICAL AND ECONOMIC INDICES OF CHEMICAL TECHNOLOGICAL PROCESSES

The purpose of chemical engineering is to carry out pro­ cesses as advantageously as possible, to transform raw mate­ rials into reaction products as fully as possible, to obtain the maximum amount of a product from the given raw mate­ rial, and to increase the product output in a reactor per time unit, i.e. to enhance the processing rate of the raw material. In this case, attempts are made to obtain a highquality product and to minimize all the expenses involved in its production. There are technical and economic indices to analyze a pro­ cess and determine its efficiency. In order to define a process, it is essential to know to what extent the raw material is utilized and how completely its chemical transformation occurs. This can be established by comparing the final amount of the reactant with its initial amount. For example, a simple irreversible reaction occurs, such as: A

B

(1.1)

Let us assume that G\0 is the initial amount of reactant A (at the beginning of the process), and GA is the amount of reactant A on completion of the process. It is necessary to establish the extent to which reactant A has undergone a chemical transformation. To this end, the amount of reactant A consumed in the reaction, GAq — GA, is related to its initial amount, GAo. The resultant value is the fraction of reactant A which has undergone chemical transformation. This value is designated as xA and is called the degree of conversion: XA

( 1. 2)

Thus, the degree of conversion is the ratio of the amount of the reactant consumed in the reaction to its initial amount.

12

Ch. 1 Technical and Economic Indices

The higher the degree of conversion xA, the greater the amount of the initial material that is reacted, and the more complete the chemical transformation process. The efficiency of the process is also determined by another index, the product yield. The product yield is the ratio of the amount of the resulting product to the maximum obtainable amount. For the reaction A B, the yield Ob is equal to: Ob

max

(1-3)

where GB is the amount of substance B which is actually ob­ tained and Gb max is the maximum amount of substance B obtainable from a given process. The maximum amount of a product yielded from a given amount of raw material is calculated by the reaction equa­ tion. Here, the content of the reactant in the raw material to be transformed should be taken into account. This can be demonstrated using an example illustrating lime (CaO) production by decomposition of calcium carbonate (CaC03) contained in limestone according to the reaction: CaC03 = CaO + C02

(1.4)

We must determine the maximum amount of CaO that can be derived from 100 kg of limestone which consists of 90 per cent CaC03. First, the amount of calcium carbonate contained in 100 kg of limestone is calculated: 100 x 90 = 100

90 kg

Next, the amount of CaO that can be produced from 90 kg of CaC03 is determined from the reaction equation: 90x56 100

50.4 kg

where 100 and 56 are the molecular weights of CaC03 and CaO, respectively. Thus, as much as 50.4 kg of CaO can be obtained from 100 kg of limestone. 1 In complex reactions, when the same starting material may undergo various chemical transformations to yield

Ch. 1 Technical and Economic Indices

13

different reaction products, it is not sufficient to evaluate the course of the process only jn terms of the degree of conversion. The degree of conversion may be high, i.e. the greater part of the starting products are reacted, but this conversion will not always lead to the formation of the desired (final) products. In addition to the desired products, some undesirable by-products may be formed. The more desired products and the less by-products are formed, the more efficiently the process occurs. Selectivity is the quan­ tity used to characterize such complex processes and to de­ termine the proportions of the desired products in the total amount of the resulting products. Selectivity is the ratio of the amount of the desired product to the total amount of the resulting products. For instance, if the process involves concurrent reactions: A

B,

A -^ D

(1.5)

where B is the desired product and D is the by-product whose amounts are represented by Gb and Gd, respectively, the selectivity cpB is equal to: