CS201972B1

CS201972B1 - The method of continuous demonomerization of the dispersion! and an apparatus for carrying it out

Info

Publication number: CS201972B1
Application number: CS239379A
Authority: CS
Inventors: Milan Vanko; Jan Richter; Anton Hagera; Ludovit Sismis; Anton Kohut; Vaclav Smejkal
Original assignee: Milan Vanko; Jan Richter; Anton Hagera; Ludovit Sismis; Anton Kohut; Vaclav Smejkal
Priority date: 1979-04-09
Filing date: 1979-04-09
Publication date: 1980-12-31

Abstract

Predmetom vynálezu je spósob a zariadenie pro teohnioký a ekonomicky efektivitu demonomerizáoiu disperzi! s použitím zariadenia v podstatě běžného typu, pričom obsah monoméru sa rádovo znižuje až na niekolko ppm. Demonomerizáoia sa uskutočňuje tak, že privádzaná disperzia o teplote 30 až 70 °C sa v prvom stupni ohřeje protiprůdne privádzanou parou z druhého etupňa na teplotu 80 až 100 °C a v druhom stupni sa uskutečňuje vlastná demonomerizáoia v podstato zá izotermlokýěh podmienok pri teplote disperzi! blízkéj teplote získanej v prvom stupni protiprúdne privádzanou parou opakované distribuovanou do disperzie a takto upravená disperzia sa vedle na 3alSle apraoovanie, pričom parná fáza z prvého atupňa sa odvédza až za prívodom disperzie homo- alebo kopolymérov vinylchloridu.The subject of the invention is a method and a device for technologically and economically efficient demonomerization of dispersions using a device of a substantially conventional type, whereby the monomer content is reduced by an order of magnitude to a few ppm. Demonomerization is carried out in such a way that the supplied dispersion at a temperature of 30 to 70 °C is heated in the first stage by countercurrently supplied steam from the second stage to a temperature of 80 to 100 °C, and in the second stage the actual demonomerization is carried out essentially under isothermal conditions at a dispersion temperature close to the temperature obtained in the first stage by countercurrently supplied steam repeatedly distributed into the dispersion, and the dispersion thus treated is taken to the next processing, whereby the vapor phase from the first stage is discharged downstream of the supply of the dispersion of vinyl chloride homo- or copolymers.

Description

Predmetom vynálezu je spdsob a zariadenie pre teohníoky a ekonomicky efektívnu 1 demonomerizáoiu disperzi! s použitím zarladenia v podstatě běžného typu* pričom ob-sah monoméru sa rádovo snižuje až na niákolko ppm. V poslednýdh rokooh, potom 80 sa zletilí karoinogénne vlastnosti vinylohloridu,venuje sa velká pozornost* odstranovaniu najnepatmejSíoh zbytkov nezreagovaného mo-noméru vo vyrábanýoh homo- a kopolymérooh vinyl ohloridu, aby vyráběné produkty nebolizdraviu Škodlivé* Na odstraňovanie zbytkov monoméru sa používá mnoho rdznyoh spóso-bov a zarladění, ktoré sa od seba lížla Speoiálnym použitím, účinnosťou a efektív-nosťou prevádZky. K najrozSírenejSím spdsobom.a zariadeniam patří stripovanie monoméruvědnou parou v desorpčnýoh kolonách so šitovými alebo mierae modifikovanými dierova-nými etážemi. Tak napr. podl'a USA pat. 8. 3 45^ 5^2 sa na demonomerizáoiu polyvlnyl-ohlorldu používá desorpčná kolona s vyohyl*ovaoími etážami. Predmetom DOS 8. 2 552 683je v podstato prooes desorpoie vinylohloridu so suspenzie polyvinylohloridu v kolo-no so šitovými etážami. Podl’a 8s. autorského osvedčenia 8. 196 386 sa používájúšitové etážé s vySSoU vstupnou přepážkou, ako je norma, priSom sa sítová etáž rie-Si ták, aby zat*aženie ploohy etáže bolo v rozmedzí 5 až 35 mJ/m plochy etáže a abyrýohlosť suspenzie v odvádzaoej Saohte bola v rozmedzí 0,05 až 0,1 m/s. Pri týohtopodmienkaoh nedoohádza k usadzovaniu tuhých Saštío. Pri predobriatí disperzie na 60až 90 °C sa na stripovanie spotřebuje 30 až 100 kg pary/m^ disperzie. Rozmedzie kon-taktně j doby na odstránenie monoméru je 1 až 30 minút. Pri desorpoii nedoohádza kZhorSeniu kvality polyméru a obsah monoméru v disperzi! možno snížit* až na 1 ppm.Podmienky závislá v prvom radě od typu vyráběného polyméru.The object of the invention is to provide a method and apparatus for teohns and an economically efficient dispersion dispersion! using an alignment of a substantially conventional type, wherein the monomer content decreases to a few ppm. In the last year, then, the carinogenic properties of the vinyl chloride have grown, much attention has been paid to the removal of the poorest residues of unreacted monomer in the homo- and copolymer of vinyl chloride produced so that the products produced are not harmful. Many different compounds are used to remove monomer residues. and aligning itself with Spiial use, efficiency, and efficiency. The most widely used methods include stripping by monomer steam in desorption columns with sewed or modified punched trays. For example, U.S. Pat. 8. The desorption column with polyvalent layers is used to demonerate polyvinyl alcohol. [0004] In principle, U.S. Pat. No. 2,552,683 discloses the desorpoxy of vinyl chloride with a suspension of polyvinyl chloride in a collar with sewed shelves. Podl'a 8s. the author's certificate 8. 196 386 is used for the stacking platform with a standard inlet partition, such as the standard, whereby the mesh tray is so that the loading of the deck platform is between 5 and 35 mJ / m of deck area and that the suspension in the drain is removed was between 0.05 and 0.1 m / s. It does not make it difficult to settle the solid Sašto when it comes to conditions. When pre-coating the dispersion at 60 to 90 ° C, 30 to 100 kg of vapor / dispersion are used for stripping. The range of contact time for monomer removal is 1 to 30 minutes. In desorption, it does not deteriorate the quality of the polymer and the monomer content of the dispersion! can be reduced to up to 1 ppm. Conditions depending on the type of polymer produced.

Tento rozSírmný spdsob stripovanie monoméru v deserpSnej koloně so šitovýmietážami je úSinný a poměrně l’ahko prevádzkovateltoý. Má aj svoje nevýhody, ktoré spo-Sívajú v zanáSaní tzv. hluchých častí etáží, a hlavně vo vysokej Speoifiokej spotře-bo stripovaoej páry a v obtiažnom regenerovaní desorbovaného monoméru.This wide-ranging method of stripping monomer in a despatch column with sewage is efficient and relatively easy to operate. It also has its drawbacks, which consist in the clogging of the so-called deaf parts of the trays, and in particular in the high disposable stripping consumption and in the difficult recovery of the desorbed monomer.

Tieto hlavné nevýhody sú odstránené postupem podl’a tohoto vynálezu, pri ktoromsa spdsob kontinu!tnej demonomerizáoie disperzi! homo- alebo kopolymérov vinylohlo-ridu pri zvýSenej teploto stripovaním priamou parou protiprúdne distribuovanou asku-toSnuje tak, že privádzaná disperzia o teplote 30 až 70 °C, s výhodou 50 až 60 °C,sa v prvom stupni ohřeje protiprúdne privádzanou parou z druhého stupňa na teplotu. 80 až 100 °C a v druhou stupni sa uskutoSňuje vlastná demonomerizáoia v podstatěza izotermiCkýoh podmlenok pri teplote disperzi! blízkéj teplote získanej v prvomstupni protiprúdne privádzanou parou opakované distribuovanou do disperzie a taktoupravená disperzia sa vedle na SalSie spraoovanie, priSom parná fáza z prvého stupňasa odvádza až za přívodem disperzie homo- alebo kopolymérov vinylohloridu. tfčelne sa postup realizuje na zariadení na principe sitovej kolony, kde vlastnědesorpčné zariadenie pozostáva z priameho výmennika tepla a sitovej kolčny konétrUk-čne spojených preohodom, pričom horizontálně ploohy jednotlivých etáži sú opatřenépo oelej ploché otvormi a na horizontálněj ploché je uohytená zvislá přepážka, pričomna spodok vlastného desorpčného zariadenia je zapojený privod paxy a odvodně potrubie,s výhodou napojené na tepelný výmenník, který je výstupným potrubím zapojený na hor**nú část* výmennika tepla vlastného desorpčného zariadenia, na ktorom je nad miestomjeho přívodu odvodné potrubie pre parnú fázu.These major drawbacks are eliminated by the process of the present invention, wherein the method of continuous demonomerization of the dispersion! vinylaluminum homo- or copolymers with an increased hot stripping by direct vapor deposition, such that the supplied dispersion at a temperature of 30-70 ° C, preferably 50-60 ° C, is heated in the first stage by countercurrently supplied steam from the second stage to temperature. 80 to 100 ° C and in the second stage, the actual demonomerization takes place essentially as isothermal condensation at dispersion temperature! near to the temperature obtained in the first-stage countercurrent vapor repeatedly distributed to the dispersion, and the dispersed dispersion being added to the sintering process, wherein the vapor phase of the first stage is removed downstream of the dispersion of the homo- or copolymers of the vinyl chloride. in particular, the process is carried out on a sieve column apparatus, wherein the self-absorbing device consists of a direct heat exchanger and a sieve bar concretely connected by an overhang, wherein the horizontal flats of the individual trays are provided with flat openings and a vertical bar is fixed on the horizontal flat, wherein the bottom of the self The desorption device is connected to a paxa inlet and a conduit, preferably connected to a heat exchanger, which is an outlet conduit connected to the upper part of the heat exchanger of its own desorption device, on which the steam phase conduit is disposed above the inlet.

Uvedený spésob demonomerlzáoie disperzi! homo- alebo kopolymérov vinylohloridua zariadenie na uskutofinenie tohoto spdsobu má prekvapujúoi účinok na zvýčenie ú-činnostl etáží a na zvýčenie praoovného rozsahu stabilného Chodu kolony pri veltainíZkej Speoifiokej spotrebe páry na demonomerizáoiu. Vysvetlenie tohoto pozitívnehovplyvu nie je jednoznačné. Sčasti ho možno pripísať uvedeným žpeoifiokým končtruk-čným úpravám, vytvárajúoim priaznivé podmienky pre intenzivny přestup tepla a hmotymedzi tuhými Sastioami polyméru, kvapalnou a parnou fázou, ktorý má pre tento ápe-oifiCký pročeš přímému ddležitosť hlavně pri demonomerizáoii polymérov oitlivýohna teplotu. Súčasne v ddsledku vysokého využitia stripovaoej paxy sa vytvárajú pria-znivé podmienky pre ekonomická regeneráoiu desorbovaného monoméru. Okrem toho novékončtrukčné rieéenie etáže prakticky vylučuje možnost' zanáčania tuhými částicemipolyméx*u. Z hl’adiska energetickoj bilanoie je výhodné na demonomerizáoiu privádzať dis-perziu priamo z autoklávu alebo oez tepelne izolovaný medzizásohník.This method of demonomerlzáoie dispersion! The vinyl chloride homo- or copolymers of this method have a surprising effect on enhancing the performance of the trays and increasing the stable range of stable column performance with the high steam consumption of the demonomer. The explanation for this positive effect is not clear. In part, it can be attributed to the aforementioned soft finishes, creating favorable conditions for intense heat transfer and mass between the rigid polymer particles, the liquid and vapor phases, which is of direct relevance to this polymerization, especially in the demonomerization of polymer-sensitive temperature. At the same time, due to the high utilization of stripped paxa, favorable conditions are created for the economic regeneration of the desorbed monomer. In addition, the new structural design of the tray virtually eliminates the possibility of clogging with solid particles. It is advantageous to disperse the dispersion directly from the autoclave or from a thermally insulated intermediate mucosa to the demoneration from hl'adiska energetická bilanoie.

Na rozdiel od inýoh postupov demonomerizáoia sa usku točnu je dvojstupňové v ú-čelne uspdsobenom zariadení, pričom sa v prvom stupni privádzaná disperzia ohřejev podstatě na teplotu blízku alebo zhodnú s teplotou demonomerlzáoie. Vlastná de-monomerizáoia sa uskutočňuje v podstatě za izotermických podmienok, z čoho rezul-tuje i vysoká Standardná kvalita demonomerizovanýCh suspenzi!.In contrast to other demonomerization procedures, the two stage process is effected in an appropriately arranged device, wherein in the first stage the dispersion introduced is heated substantially to a temperature close to or equal to the temperature of the demonomer. The actual de-monomerisation is carried out essentially under isothermal conditions, which results in a high standard quality of the demonomerized suspension.

Produkt je Standardný, poměrně dobré sa dá dodržiavať vopred zvolený technolo-gický režim, dosahuje sa efektivnost’ aj v pomeme nízkéj spotrebe paxy.The product is Standard, it is quite good to observe a pre-selected technology mode, achieve efficiency, and relatively low pax consumption.

Vlastná desorpoia monoméru sa uskutočňuje na horizontálnych plochách šitovýchetáži 4 desorpčného zariadenia pomooou priamej páry privádzanoj potrubím 2. pri kon-taktně j době a teplo tných podmienkach podl*a typu vyráběného polyméru resp. kopolyméru.Desorpčné zariadenie s horizontálnymi plochami sítových etáží h pozostáva z dvochčastí - z priameho výmennika tepla 2. s najmenej jednou horizontálnou plochou etáži 4,ktorý je preohodom 2. spojený so šitovou kolenou Z ako druhou časťou zariadenia. Napriamy tepelný výmenník 1 je zapojené výstupné potrubie disperzie 10, ktoré je súčas-ne aj výstupným potrubím z nepriameho tepelného výmennika v ktorom sa na predó- hriatie privádzanej disperzi· využívá teplo odvádzané z demanomerizovaaej disperzi·t která sa týmto súSasne oohladzuje.The actual desorpolation of the monomer is carried out on the horizontal surfaces of the desorption device 4 by direct steam being fed via line 2 at the time and temperature conditions according to the type of polymer produced. The adsorption device with horizontal screen shelf surfaces h consists of two parts - a direct heat exchanger 2 with at least one horizontal shelf surface 4, which is connected to the seam knee Z as the second part of the device. The direct heat exchanger 1 is connected to the outlet pipe of the dispersion 10, which is also an outlet pipe of an indirect heat exchanger in which the heat dissipated from the demanomerized dispersion is used to pre-heat the dispersion to be dispersed.

Vlastaá desorpoia prebieha pri intenzívnom rozptylováni vadnej páry v disperziipolymóru, protékájúoej na šitových etážaoh 4. Pri zariadeni podl*a vynálezu nie je si-tevá etáž h vystrojená bežne používanou vstupnou rozdelovaoou přepážkou, ale je pooelej úSinnej plocho i v priestore pod prepadom vymedzenou zvislou přepážkou 6 a ob-vodovým pláSťom sitovej kolony 2 opatrenej otvonni £. Rovnakým spdsobom sú vystroje-né i etáže priameho výmennika tepla 1.Desorpoia occurs when vapor is dispersed vigorously in the dispersion polymorph flowing onto the sewage trays 4. In the device according to the invention, the tray is not equipped with a commonly used inlet divider but is also provided with a flat surface in the space under the overflow defined by a vertical partition 6 and a circumferential casing of a sieve column 2 provided with an opening 6. In the same way, the trays of the direct heat exchanger 1 are equipped.

Uvedené příklady ilustrujú, ale nevymedzujú rozsah použitia prs rdzne druhy dis-perzii poiyvinylohloridu a rézne spraoovávané množetvá. Přiklad 1These examples illustrate, but do not limit, the application of the various types of polyvinyl chloride dispersions and the rhodoporous copolymers. Example 1

Na demenomerizáoiu sa používá suspenzia poiyvinylohloridu citlivého na teplotu.Vodná suspenzia kontinu!tne privádzaná v množstvo 550 l/h obsahuje 25 % hmot. tuhýchSastlo poiyvinylohloridu. Obsah nezareagovaného monoméru Sini 8 400 ppm, Desorpoiasa uckUioSnuje kontinu!tne na zariadeni sohéaatieky znázomonom na obr. 1. DesorpSnézariadenie jo vystrojené šitovými otážami nasledujúoioh základných rozmerov: priemer etáže priemar otvorov celková plooha otvorovvýžka propaduvzdialonosť medzi otážamiprieroz propaduvstupný prieroz suspenziaz propadu na etáždlžka přepadovéJ přepážkyzaťaženie plochy etážerýOhlosť v přepade 158 mm 2 mm 11,48 /fc plochy etáže75 4 30 mm 240 mm17,09 om2 16,5 om2108 mm 38,6l np/m2 etáže, h0,089 m/s.A temperature-sensitive suspension of polyvinyl vinyl chloride is used for the demenomerization. solid stiff polyvinyl chloride. The content of the unreacted Sini 8 400 ppm monomer, Desorpoiasis, continually persists on the apparatus shown in Figure 1. floor leveling overflow 158 mm 2 mm 11,48 / fc floor area75 4 30 mm 240 mm17,09 om2 16,5 om2108 mm 38,6l np / m2 floor, h0,089 m / s.

Privádzaná suspenzia sa najprv predohrieva v tepelnom výmenniku na teplotu 58 °Ca potom sa vovádza do priameho výmennika tepla na vrohu desorpčného zariadenia. Dospodu deaorpžSného zariadenia sa privádza para 0,6 MPa v množstvo 27,0 kg/h. Desorpoiamonoméru prebieha v desorp&nom zariadeni pri teplotáoh 98 až 103|OC, prléom odohádzá-júoa vodná para s desertovaným monomérom z v&SSej Sas ti skondonzujo pri styku s přive-denou susponzlou na šitových otážaoh priameho výmennika tepla, ktoré sú podobnéj kon-Strukoie ako desorpSné etáže, ale o priemere 70 mm. Z priameho výmennika tepla potomodohádza zmes vodnéj páry a desorbovaného monoméru o konoentráoii 00a 46 $ hmot. Zospodu desorpSaého zariadenia odohádza odplynoná suspenzia s obsahem monoméru pod5 ppm pri kontaktněj době oea 2,5 mlnúty. Špeoifioká spotřeba páry na desorpoiu 6inipo odSitani teoretické množetvá páry, potřebného na prodohrov suspenzi· na desorpúnúThe feed suspension is first preheated in a heat exchanger to a temperature of 58 ° C and then introduced into a direct heat exchanger at the desorption device. The adult deactivation device is fed with a steam of 0.6 MPa in an amount of 27.0 kg / h. The desorpoiamonomer runs in a desorption apparatus at a temperature of 98-103 ° C, while the water vapor with the disintegrated monomer from the sapon is disposed of in contact with the incoming suspension on the sewn-in-turn of a direct heat exchanger similar to that of the heat exchanger. Strukoie as desorps, but 70 mm in diameter. Then, from a direct heat exchanger, a mixture of aqueous vapor and desorbed monomer provides a concentration of 00 and 46% by weight. From the bottom of the desorption device, the degassing suspension with a monomer content of less than 5 ppm releases about 2.5 ml. Sparse steam consumption for desorpolation 6inipo desiccation of the theoretical amount of steam required for the desorption slurry

Claims

temperature, about 14 kg / m 2 suspension ». Example 2 The same apparatus and process as in Example 1, except that the feed slurry is preheated in the heat exchanger 100 to h-9 ° C and is introduced into the de-sorption apparatus at this temperature. Water vapor is discharged from the superstructure of the desorption device with a content of 40 wt. monomer. Sparse steam consumption increases to about 17 kg / m 2 of suspension. The desire to disorient is diminished. From the desorption device, a degassing suspension with a monomer content of 5 to 10 ppm is evidently recovered at a rate of 37.5 kg / h as a result of the deterioration of the device's performance at a higher steam supply. Example 3 The same apparatus and procedure as in Example 1, except that the feed suspension is preheated to a temperature of 70 ° C. This is achieved in the same manner as in Example 1. Sparse steam consumption is increased to 26 kg / h (after subtraction of theoretic consumption and preheating) and the monomer concentration in the desorption apparatus is reduced to 20% by weight. EXAMPLE 4 The same equipment as in Example 1 is used on the demonomerization, with the difference that the openings in the overflow tray are flushed, and an inlet partition according to the commonly used construction of the Shitoy tray is placed at the inlet of the overflow drawer. The suspension is fed at 550 l / h and preheated in a heat exchanger to 60 ° C. The monomer content is 1112 ppm. The adsorption takes place at a temperature of 98 ° C to 103 ° C. The amount of direct steam supplied is 26.0 kg / h. The slurry from the bottom of the desorption apparatus contains 25 to 30 ppm of monomer. In addition to the deterioration of desorpo- ria, a co-pressing of the pressure drop can be observed in the past, indicating a deteriorated stability of the device. SUBJECT MATTER

1. Spdsob continoit demonomerizáoio dispersion! homo- or copolymer vinyl chloride in the case of increased direct stripping by direct steam distribution, making it possible for the dispersion to be supplied at a temperature of 30-70 ° C, preferably 50-60 ° C, to be heated upstream of the second stage by countercurrent steam temperature 80 to 100 ° C and in the second stage the actual demonomerization is carried out essentially under isothermal conditions in a warm dispersion! the near-temperature obtained in the first stage countercurrently supplied by the jara repeatedly distributed to the dispersion, and the dispersion thus treated is furthermore subjected to further treatment, the vapor phase of the first stage being exhausted downstream of the dispersion of the homo- or copolymers of the vinyl chloride.

2 / A method according to claim 1 for applying a screen column, characterized in that the actual desorption device comprises a direct heat exchanger (1) and a sewing column (2) structurally connected to the overhang (3) with a horizontal surface of the single column the trays (4) are provided with a flat wall (5) and a vertical partition (6) fixed on the horizontal surface, a steam supply (7) and a discharge conduit (8), preferably connected to the underside of the desorption device (7), the heat exchanger (9) is an outlet conduit (10) connected to the top of the heat exchanger of its own desorption device, on which a conduit for the phage memory (11) is disposed above its supply point. 2 vylcresy