CONVERSION AND REACTOR SIZING (2) Marcel Lacroix Université de Sherbrooke

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1 CONVERSION ND RECTOR SIZING (2) Marcel Lacroix Université de Sherbrooke

2 CONVERSION ND RECTOR SIZING: OBJECTIVES 1. TO DEINE CONVERSION j. 2. TO REWRITE THE DESIGN EQUTIONS IN TERMS O CONVERSION j. 3. TO SIZE IDEL RECTORS BY EMPLOYING THE RELTIONSHIP BETWEEN THE RECTION RTE r j ND CONVERSION j. 4. TO EMINE IDEL RECTORS CONNECTED IN SERIES. M. Lacroix Conversion and Reactor Sizing 2

3 DEINITION O CONVERSION CONSIDER THE CHEMICL RECTION a + bb cc + dd I SPECIES IS TKEN S THE BSIS O CLCULTION, b c + B C + a a D THEN CONVERSION IS DEINED S d a moles of moles of reacted fed ; ( < < 1) M. Lacroix Conversion and Reactor Sizing 3

4 DESIGN EQUTION OR BTCH SYSTEMS: RELTIONSHIP BETWEEN N ND THE NUMBER O MOLES O THT HVE RECTED TER TIME t IS: N THE NUMBER O MOLES O THT REMIN IN THE RECTOR TER TIME t IS THEN: N N (1 N N ) M. Lacroix Conversion and Reactor Sizing 4

5 DESIGN EQUTION OR BTCH SYSTEMS: MSS BLNCE IN TERMS O r ND OR PERECTLY MIED RECTION MITURE, dn r V dt SUBSTITUTING OR N N N YIELDS N d dt r V THE TIME NECESSRY TO CHIEVE CONVERSION IS ( t) d t N r V M. Lacroix Conversion and Reactor Sizing 5

6 DESIGN EQUTION OR LOW SYSTEMS: RELTIONSHIP BETWEEN ND I IS THE MOLR LOW RTE O SPECIES ED TO SYSTEM OPERTED T STEDY STTE, THE MOLR RTE T WHICH SPECIES IS RECTING WITHIN THE ENTIRE SYSTEM WILL BE : [ moles of fed] [ time] THE MOLR LOW RTE O LEVING THE SYSTEM IS EQUL TO THE MOLR EED RTE O TO THE SYSTEM MINUS THE RTE O RECTION O WITHIN THE SYSTEM : [ moles of reacted] [ moles of fed] (1 M. Lacroix Conversion and Reactor Sizing 6 )

7 C v DESIGN EQUTION OR LOW SYSTEMS: RELTIONSHIP BETWEEN ND C C v :ENTERING MOLR LOW RTE (moles/time) :ENTERING CONCENTRTION (moles/litres) :ENTERING VOLUMETRIC LOW RTE (litres/time) P y P OR GS SYSTEMS, C WHERE RT RT y :ENTERING MOLE RCTION O P :ENTERING TOTL PRESSURE (kpa) T :ENTERING TEMPERTURE (K) P :ENTERING PRTIL PRESSURE (kpa) R: IDEL GS CONSTNT (8.314 ) M. Lacroix Conversion and Reactor Sizing 7 kpa litre mole K

8 EMPLE No. 1: RELTIONSHIP BETWEEN ND C GS MITURE CONSISTS O 5% ND 5% INERTS T 1 TM (113 kpa) ND ENTERS THE RECTOR WITH LOW RTE O 6 liters/s T 422 K. CLCULTE THE ENTERING CONCENTRTION O, C, ND THE ENTERING MOLR LOW RTE,. M. Lacroix Conversion and Reactor Sizing 8

9 DESIGN EQUTION OR CSTR: MSS BLNCE IN TERMS O r ND MSS BLNCE OR MIED LOW RECTOR: r V SUBSTITUTING OR,THE CSTR VOLUME NECESSRY TO CHIEVE SPECIIED CONVERSION IS V ( r ) exit M. Lacroix Conversion and Reactor Sizing 9

10 DESIGN EQUTION OR PR: MSS BLNCE IN TERMS O r ND MSS BLNCE OR PLUG LOW RECTOR: d dv r SUBSTITUTING OR,THE PR VOLUME NECESSRY TO CHIEVE SPECIIED CONVERSION IS V d r M. Lacroix Conversion and Reactor Sizing 1

11 DESIGN EQUTION OR PBR: MSS BLNCE IN TERMS O r ND MSS BLNCE OR PCKED BED RECTOR: d r ' dw SUBSTITUTING OR, d r ' dw THE CTLYST MSS W NECESSRY TO CHIEVE CONVERSION WHEN THE TOTL PRESSURE REMINS CONSTNT IS W d r ' moles reacted/(g of catalyst second) M. Lacroix Conversion and Reactor Sizing 11

12 RECTORS CONNECTED IN SERIES WYS O PROCESSING LUID: TYPE O RECTOR,CHIN O RECTORS, HETING, RECYCLING, ETC. CTORS TO BE CONSIDERED: RECTION TYPE, SCLE O PRODUCTION, COST O EQUIPMENT ND PRODUCTIONS, SETY, STBILITY ND LEIBILITY O OPERTION, EQUIPMENT LIE EPECTNCY, ETC. CHOICE : DICTTED BY THE ECONOMICS. IRST CTOR IS RECTOR SIZE; SECOND CTOR IS PRODUCT DISTRIBUTION. OR RECTORS CONNECTED IN SERIES,THE EIT STREM O ONE RECTOR IS THE EED STREM OR NOTHER RECTOR. M. Lacroix Conversion and Reactor Sizing 12

13 RECTORS CONNECTED IN SERIES: EMPLE RECTORS CONNECTED IN SERIES: EMPLE 1 1 r d V ) ( r V r d V reactor first to fed of mole to up reacted of moles total 2 2 M. Lacroix Conversion and Reactor Sizing 13

14 EMPLE No. 2: DESIGN O RECTORS KNOWING r () USING THE OLLOWING DT (TKEN T 422 K ND 1 TM), CLCULTE THE VOLUME NECESSRY TO CHIEVE 8% CONVERSION IN CSTR: r /-r THE RTE O DISPPERNCE O IS IN mole/(liter.s). THE ENTERING MOLR LOW RTE IS THE SME S BEORE, i.e.,.867 mole / s NOW THE RECTION IS TO BE CRRIED OUT IN PR. CLCULTE THE RECTOR VOLUME NECESSRY TO CHIEVE 8% CONVERSION. M. Lacroix Conversion and Reactor Sizing 14

15 DESIGN O RECTORS KNOWING r (): SOLUTION r 1/r d*(1/r),53 188,679245,1,52 192, ,493469,2,5 2 19, ,3,45 222, , ,4, , ,5,33 33,333 27, ,6, , ,7,18 555, , ,8, , ,88,85, , , V d. 867 r d r INTEGRTION IS PERORMED WITH THE TRPEZOIDL RULE.8 V ( r ) exit M. Lacroix Conversion and Reactor Sizing 15

16 EMPLE No. 3: DESIGN O RECTORS CONNECTED IN SERIES KNOWING r () CONSIDER TWO CSTRs CONNECTED IN SERIES. 4% CONVERSION IS CHIEVED IN THE IRST RECTOR. WHT IS THE TOTL VOLUME O THE TWO RECTORS NECESSRY OR 8% OVERLL CONVERSION O THE SPECIES ENTERING RECTOR 1? REPET THE CLCULTIONS OR TWO PRs CONNECTED IN SERIES. WHT CONCLUSIONS CN BE DRWN? EMINE THE CSES O CSTR CONNECTED IN SERIES WITH PR. THE INTERMEDITE CONVERSION IS IED T 1 5% ND THE OVERLL CONVERSION REMINS T 8%. M. Lacroix Conversion and Reactor Sizing 16

Module 2: Rate Law & Stoichiomtery (Chapter 3, Fogler)

Module 2: Rate Law & Stoichiomtery (Chapter 3, Fogler) CHE 309: Chemicl Rection Engineering Lecture-8 Module 2: Rte Lw & Stoichiomtery (Chpter 3, Fogler) Topics to be covered in tody s lecture Thermodynmics nd Kinetics Rection rtes for reversible rections