Process development for upgrading low value α C8-olefin from Fischer-Tropsch to 2-hexyl-nonanal

Thesis (MEng)--Stellenbosch University, 2016.ENGLISH ABSTRACT: A wide variety of speciaIty chemicals are now available from technology based on the olefin metathesis reaction. This versatile reaction aIIows the conversion of simpIe, relatively inexpensive olefins into specialty, high-purity olefins which are useful intermediates in the fragrance, agricuIturaI, and many other specialty chemical industries. Literature has shown that low value (C5-C9) olefins produced from a Fischer-Tropsch reaction can be used as important feedstocks for the manufacture of high value, detergent range linear internal alkenes (C10-C18). These detergent range internal alkenes could then be subsequently functionalised during hydroformylation to asymmetric aldehydes, which can be used as intermediates for manufacturing Guebert-type surfactants. The DST-NRF Centre of Excellence in Catalysis (change) have investigated the efficacy of homogeneous catalysts towards upgrading low value, unique olefinic feedstocks from a Fischer-Tropsch product stream through the RSA Olefins programme. The homogeneous catalysts are reported to be highly selective and reactive but are not employed industrially because they are expensive and decompose as the high boiling products are distilled from the reaction medium. Hence, the RSA Olefins programme of the DST-NRF Centre of Excellence in Catalysis has been active in developing organic solvent nanofiltration (OSN) membrane technology to allow for efficient separation and subsequent recycling of the homogeneous catalysts. Using literature sources and industrial catalogues, an initial screening of catalyst systems was done to select candidate catalytic systems for the metathesis of low value 1-octene (C8) and the subsequent hydroformylation of 7-tetradecene (C14) to detergent range products. The criteria such as catalyst cost, selectivity (product distribution), turnover number (TON) together with economic potential (EP) values determined at five levels of design were used to develop candidate processes using the Douglas hierachichal method. The Hoveyda-Grubbs 2 (HGr-2) precatalyst and water-soluble Rh-TPPTS were selected for the metathesis of 1-octene and hydroformylation of 7-tetradecene respectively. Two process scenarios A (liquid multiphase system) and B (OSN membrane) were developed and evaluated using a techno-economic analysis (TEA) model. The viewpoints of design and performance were developed by integrating the technical and economic information through Aspen PlusTM process simulation and sensitivity analysis of the key operating parameters. The goal was to detect promising process concepts as early as possible and to single out the crucial parameters such that experimental and modelling work can be focused on those alternatives that most likely will lead to an economic process. The discounting cash flow (DCF) method was used to evaluate the two process scenarios A (liquid multiphase system) and B (OSN membrane process) producing 10 000 tonnes per annum of 2-hexyl-nonanal at a purity of 99 wt. %. The feedstock to be used is low value 1- octene a Fischer-Tropsch Synthol product stream. The performance criterion is to maximise the net present value (NPV) of the process. The NPV included revenues, total capital investment and depreciation costs was determined based on interest rate of 15 % and the lifetime of 15 years. Economic parameters such as internal rate of return (IRR %) and payback period (PBP) were calculated for each scenario. The results were then used to determine the configuration with the most favourable economic indicators. The two process scenarios studied proved to be profitable with IRR % ranging between 58 % and 83 % with scenario B having the highest NPV and IRR %. The NPV for scenario A and scenario B were $ 439 M and $ 563 M respectively at the end of project life of 15 years. The IRR % for process scenario A was 59 % compared to scenario B of 83 % for the same pay back period of 3 years. Sensitivity analysis were performed on the two process scenarios. The parameters investigated were: 2-hexyl-nonanal selling price; Rh-TPPTS catalyst cost; 1-octene feed cost; HGr-2 catalyst cost and tax rate %. Their impact on NPV and IRR % was evaluated. Curve diagrams were constructed to illustrate the effect of variation of different cost parameters on NPV and IRR %. The most effective input variables for the two process scenarios were 2-hexyl-nonanal selling price, Rh-TPPTS and HGr-2 catalyst cost on both NPV and IRR. The process scenario B which considers OSN membrane technique for catalyst recovery was the most profitable configuration and the NPV was 22 % better than the liquid multi phase system.AFRIKAANSE OPSOMMING: ʼn Groot verskeidenheid gespesialiseerde chemikalieë is hedendaags beskikbaar te danke aan tegnologie wat gebaseer is op die olefiene-metathesis reaksie. Hierdie veelsydige reaksie laat die omskakeling van eenvoudige en relatief goedkoop olefiene toe na meer gespesialiseerde, suiwer olefiene. Hierdie meer gespesialiseerde olefiene, is bruikbare oorbrugging chemikalieë vir die parfuum, landbou en verskeie ander chemiese industrieë. Literatuur wys daarop dat lae-waarde (C5-C9) olefiene, wat geproduseer word vanaf die Fisher-Trospch reaksie, gebruik kan word as belangrike roumateriale vir die vervaardiging van waardevolle, lineêre interne skoonmaakmiddel-reeks alkene (C10-C18). Hierdie reeks internerne skoonmaakmiddel alkene, kan gevolglik gefunctionaliseer word tydens hidroformilasie tot asimmetriese aldehiede, wat gebruik kan word as intermediêre middels vir die vervaardiging van Geubert-tipe benatters. Die doeltreffendheid van homogene katalisators om lae waarde, unieke olefiene voerstowwe van die Fischer-Tropsch synthol produkstroom op te gradeer, is ondersoek deur die olefiene program DST-NRF Centre of Excellence in Catalysis. Dit word gerapporteer dat die homogene katalisators hoogs selektief asook reaktief is, maar dat dit nie industrieel in werking gestel word nie, omdat dit baie duur is en ontbind tydens die distillasie proses, wanneer die produkte gedistilleer word vanaf die reaksie medium. Daarom is die olefiene program van die DST-NRF Centre of Excellence in Catalysis aktief besig om organiese oplosmiddel-nanofiltrasie (OSN) membraan tegnologie te ontwikkel, wat effektiewe skeiding en daaropvolgende herwinning van die homogene katalisator, toe te laat. ʼn Aanvanklike keuring van katalisators is gedoen, om kandidaat katalisator sisteme te identifiseer deur die gebruik van literatuur bronne en industriële katalogusse, vir die metatesis van lae waarde 1-okteen (C8) en daaropvolgende hidroformilasie van skoonmaakmiddels 7-tetradekeen (C14) produk alkene. Katalisator koste, selektiwiteit (produk distribusie), TON tesame met EP waardes (teen 5 ontwerpsvlakke) is gekies vir die kriteria om katalisator sisteme te skep. Hierdie sisteme is geskep deur die hiërargiese metode soos gestipuleer in Douglas (1988). HGr-2 voor-katalisator en water oplosbare Rh-TPPTS was gekies vir die metatesis van 1-okteen en daaropvolgende hidroformilasie van 7-tetradekeen, onderskeidelik. Twee proses scenario’s, scenario A (vloeistof multi-fase sisteem) en scenario B (OSN membraan) was ontwikkel en deur ʼn tegno-ekonomiese analise (TEA model) te ondersoek. Die ontwerp en prestasie oogpunte was ontwikkel deur die tegniese en ekonomiese inligting in die simulasie program (Aspen PlusTM) te integreer, asook deur die sensitiwiteitsanalises van die kern bedryf parameters. Die doel was om belowende proses konsepte so vroeg as moontlik te identifiseer, en dus ook die kern parameters, sodat eksperimentele en modelleringswerk só opgestel kon word om te lei na die mees belowende ekonomiese prosesse. Die verdiskontering kontantvloei (DCF) metode was gebruik om die twee proses scenario’s, A (vloeistof multifase sisteem) en B (OSN membraan proses), te evalueer teen 10 000 ton per jaar 2-heksiel-nonanal, met ʼn massa suiwerheid van 99% vanaf die lae waarde 1-okteen Fischer-Tropsch Synthol produkstroom. Die Ekonomiese parameters, soos die internerne opbrengskoers (IRR %), terugbetalingstydperk (PBP) en netto huidige waarde (NPV), was bereken vir elke scenario. Die resultate is gebruik om die opset met die mees gunstige ekonomiese aanwysers te bepaal. Dit is gevind dat die twee proses-scenario’s (A en B), ekonomies gunstig is, met IRR % waardes wat varieer tussen 58 en 83%. Scenario B het die hoogste NPV en IRR %. Die NPV vir scenario A en B, teen die einde van die 15 jaar projek lewe, was $ 439 M en $563 M onderskeidelik. Die IRR % vir proses scenario A was 59 % in vergelyking met scenario B wat 83 % was vir dieselfde terugbetalingstydperk van 3 jaar. Die twee proses-scenario’s het ook sensitiwiteitsanalises ondergaan. Die parameters wat ondersoek is sluit die verkoopsprys van 2-heksiel-nonanal, Rh-TPPTS katalisator koste, 1-okteen voerstof koste, HGr-2 katalisator koste en rente koerse % in. Die impak van die verkeie parameters op die NPV en IRR % is ondersoek. Kurwe diagramme is opgestel om die invloed van die verskillende parameter kostes op die NPV en IRR % parameters aan te dui. Die mees doeltreffende inset veranderlikes vir die twee proses scenario’s was die verkoopsprys van 2-heksiel-nonanal en die prys van die Rh-TPPTS en HGr-2 katalisators op die NPV en IRR % parameters. Proses scenario B, wat die OSN membraan tegniek insluit vir katalisator herwinning, is gevind om die mees ekonomiese winsgewende opset te wees. Die NPV was 22 % beter as scenario A, wat die multifase sisteem gebruik het