Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C303/00—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides
  • C07C303/02—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides of sulfonic acids or halides thereof
  • C07C303/04—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides of sulfonic acids or halides thereof by substitution of hydrogen atoms by sulfo or halosulfonyl groups
  • C07C303/06—Preparation of esters or amides of sulfuric acids; Preparation of sulfonic acids or of their esters, halides, anhydrides or amides of sulfonic acids or halides thereof by substitution of hydrogen atoms by sulfo or halosulfonyl groups by reaction with sulfuric acid or sulfur trioxide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/18—Stationary reactors having moving elements inside
  • B01J19/1856—Stationary reactors having moving elements inside placed in parallel
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J19/18—Stationary reactors having moving elements inside
  • B01J19/1862—Stationary reactors having moving elements inside placed in series
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00002—Chemical plants
  • B01J2219/00027—Process aspects
  • B01J2219/00031—Semi-batch or fed-batch processes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00002—Chemical plants
  • B01J2219/00027—Process aspects
  • B01J2219/00036—Intermittent processes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00049—Controlling or regulating processes
  • B01J2219/00164—Controlling or regulating processes controlling the flow
  • B01J2219/00166—Controlling or regulating processes controlling the flow controlling the residence time inside the reactor vessel
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
  • B01J2219/00049—Controlling or regulating processes
  • B01J2219/00182—Controlling or regulating processes controlling the level of reactants in the reactor vessel

Definitions

• the present invention relates to the technology to carry out a continuous chemical process in a liquid reaction mixture, using continuous stirred tank reactors (CSTR).
• CSTR continuous stirred tank reactors
• a modified, improved method to carry out a chemical process running in the kinetic area, specifically relatively slow chemical reactions of ageing a post-sulfonation mixture in a plant producing alkylbenzenesulfonic acid (LABSA) by sulfonating alkylbenzene using a sulfonating agent, particularly sulfur trioxide, is the subject of the invention.
• the invention relates to the plant for conducting the above-mentioned improved ageing method and to a method for the plant operation.
• the invention relates to a modified, improved method to conduct the process of ageing a post- sulfonation mixture in an plant producing alkylbenzenesulfonic acid (LABSA), using a system of two or more stirred tank reactors, operated in a combined batch-and-continuous manner, comprising the reactor operation steps in a continuous unsteady state and steps of operation in batch process conditions as well as to a method to modify the ageing unit for handling the post-sulfonation mixture of an existing chemical facility, by means of a solution presented in the description of the invention.
• LABSA alkylbenzenesulfonic acid
• the process conditions in the proposed solution are similar to a batch process or to a continuous process being carried out in a plug-flow tubular reactor, which enables elimination of dilution of the maturing reaction mixture with the incoming "fresh" stream of unreacted reaction mixture, which takes place in a continuous process, furthermore, the product has much better quality-determining parameters, such as the content of active matter (AM), unreacted substrate, and color.
• AM active matter
• Alkylbenzenesulfonic acid is an anionic surfactant and essential component of detergent formulations (mainly in its sodium salt form) for household and industrial use, a component of washing, dish-washing, and cleaning powders and liquids.
• LABSA is also used in other industries as a component of mixtures used for modifying the surface properties of aqueous solutions.
• a well established state-of-the-art method to obtain alkylbenzenesulfonic acid in a commercial scale is based on the sulfonation of alkylbenzene after obtaining it usually by alkylation of benzene in the presence of a Friedel-Crafts catalyst.
• the sulfonating agents used are 20% oleum, sulfuric acid or sulfur trioxide or, less frequently, chlorosulfonic acid.
• the most frequently used commercial method to obtain alkylbenzenesulfonic acid is by sulfonation with sulfur trioxide.
• the process of technology to manufacture LABSA by sulfonation with S0 3 comprises a number of steps, such as the obtaining of sulfur trioxide by sulfur combustion to obtain sulfur dioxide and its catalytic conversion as well as reacting sulfur trioxide with an organic raw material (alkylbenzene), digestion, hydrolysis of anhydrides and optional neutralisation.
• the commercial sulfonation facilities which are used at present and are based on the processes of technology licenced by e.g. DESMET BALLESTRA S.p.A., CHEMITHON, MAZZONI and other ones.
• the ageing process is effected by using a retention volume in the form of a typical, usually single continuous stirred tank reactor, operated at steady-state conditions.
• Information about that commonly used process of technology is provided in generally available descriptions and studies (e.g.: H. de Groot: Sulfonation Technology in the Detergent Industry. BALLESTRA S.p.A. Kluwer Academic Publisher, Dodrecht-Boston-London 1991 ).
• Alkylbenzenesulfonic acid which is commercially obtained in a process of technology comprising a naturally fast sulfonation reaction and a naturally slow ageing process, typically contains >90% of what is called active matter in the form of alkylbenzenesulfonic acid, approx. 0-3% of a matter other than the useful component, so-called free oils, and small amounts of water and sulfuric acid.
• the free oils fraction should contain ⁇ 1 % sulfones, only traces of paraffins which contaminate the LAB raw material, and ⁇ 3% of linear alkylbenzene - the unreacted raw material. While the last mentioned component is a raw material which can be converted to obtain a useful component, both the sulfones and the paraffins are impossible to be converted to useful sulfonates, thus limiting process yield.
• LAB conversion to LABSA may be improved by extending its time of residence in the ageing unit, which is generally known to those skilled in the art.
• those skilled in the art are aware of the fact that a maximum increase in conversion in the ageing process being conducted in a conventional state-of-the-art process of technology, i.e., in a CSTR reactor, is observed during the initial first hour. After that time, the increase in conversion is rather low; on the other hand, the process of ageing in conditions of high average residence times for the reaction mixture in CSTR's (large reactor tank volumes), has the disadvantage of side processes which occur leading to deep coloration of final product, as measured in the Klett color scale.
• the obtained active matter content was 98.2% while the content of unreacted LAB was reduced to 0.0-0.1 %.
• the color of the resulting product was rather low ( ⁇ 13) while conventional processes which are established in the art provide products with Klett colours of above 30 for comparable deep conversions of LAB; this disqualifies the products as raw materials for e.g. liquids, which require LABS with Klett colours of 25 or less.
• two or more stirred tank reactors are used so that the tanks are operated in cycles in filling steps, during which there runs the first step of continuous ageing at nonsteady-state conditions, followed by ageing steps in batch process conditions.
• modification consists in adding more tank reactors, in a particular case, one reactor.
• the gist of the invention is in the method to operate the reactor system, enabling the process conditions in the proposed solution to be similar to those of a batch process or to the operating conditions prevailing in a plug-flow tubular reactor, where the reaction mixture will not become diluted with more portions of "fresh" post-sulfonation mixture.
• the resulting improved reaction yield follows directly from the reactor's basic mass balance.
• the ageing process is carried out at unsteady-state conditions in its first step while feeding the reactor at a rate which is determined by the plant throughput, whereupon, after filling the first reactor and reaching a conversion which results from the time of filling the tank, the feeding process is discontinued and the second step of ageing is commenced in strictly batch process conditions without feeding the stream of unreacted post-sulfonation mixture.
• the level of LAB decreases at a faster rate without being disturbed by more portions of the unreacted mixture; this results directly from the reactor's mass balance for this step of the process.
• the second tank reactor in which there runs the ageing process at unsteady-state conditions, is filled during the second step.
• the first reactor is emptied batchwise and the aged reaction mixture is sent to the hydrolysis reactor which is operated as a batch reactor in spite of being known in the art as a continuous reactor, and then is sent to a storage tank after being cooled down in a heat exchanger which is known in the art.
• the invention is thus directed to a method for ageing a liquid post-sulfonation reaction mixture comprising linear alkylbenzenesulfonic acid (LABSA) and unreacted linear alkylbenzene (LAB), said reaction mixture being obtained by a continuous chemical process of sulfonating linear alkylbenzene using a sulfonating agent, the method using a system of two or more stirred tank reactors and comprising the steps of:
• LABSA linear alkylbenzenesulfonic acid
• LAB unreacted linear alkylbenzene
• a system of two stirred tank reactors is used and steps (iii) and (iv) are performed while feeding the continuous stream of reaction mixture into the second stirred tank reactor and prior to reaching the predetermined maximum reaction mixture level in the second stirred tank reactor.
• a system of three or more stirred tank reactors is used and steps (iii) and (iv) are performed while feeding the continuous stream of reaction mixture into the second, third or any subsequent stirred tank reactor and prior to reaching the predetermined maximum reaction mixture level in the second, third or any subsequent stirred tank reactor.
• the volume of the stirred tank reactors may be selected such that ageing and removing the reaction mixture from a given stirred tank is completed before the next cycle of feeding the continuous reaction mixture stream into said given tank reactor starts.
• the method further comprises the step of (ix) feeding the aged reaction mixture into a hydrolysis reactor where it is combined with an amount of water necessary to stabilize the aged reaction mixture, preferably ⁇ 2 wt.-% water relating to the amount of the aged reaction mixture, wherein the hydrolysis reactor preferably has a volume equal to or larger than that of the largest stirred tank reactor used for ageing the reaction mixture; and optionally (x) feeding the stabilized aged reaction mixture, optionally after cooling, into a final product storage tank.
• Each of the stirred tank reactors may comprise (a) at least one inlet, preferably having a valve and preferably being arranged at the top or the upper half of the stirred tank reactor; (b) at least one closable outlet, preferably having a valve and preferably being arranged at the bottom of the stirred tank reactor; (c) at least one level indicator allowing to determine the maximum reaction mixture level in said reactor; and/or (d) a cooling system to control the reaction mixture temperature in the reactor.
• the step of feeding the reaction mixture into a tank reactor is performed in about 0,5 to about 2 h, preferably in about 1 h.
• the steps of feeding the reaction mixture into a tank reactor, ageing the reaction mixture in the tank reactor and removing the aged reaction mixture may be performed in about 1 ,5 to about 3 h, preferably in about 2 h.
• the present invention relates to a plant for the production of linear alkylbenzenesulfonic acid (LABSA) by a continuous chemical process of sulfonating linear alkylbenzene (LAB) using a sulfonating agent, the plant comprising a sulfonation unit and an ageing unit, characterized in that the ageing unit comprises two or more parallely operated ageing reactors and a single stabilization reactor, wherein the two or more ageing reactors are each connected to a common pipeline that alternately feeds a reaction mixture obtained in the sulfonation unit into said ageing reactors via an inlet stub pipe, and a common pipeline that feeds the aged reaction mixture into said stabilization reactor via an outlet stub pipe.
• LABSA linear alkylbenzenesulfonic acid
• LAB linear alkylbenzenesulfonic acid
• the stabilization reactor (R4) may have a volume larger than or equal to the volume of the largest ageing reactor (R1 , R2, R3).
• each ageing reactor comprises: (a) a valve (V1.1 , V2.1 , V3.1 ) for opening and closing the inlet stub pipe; (b) a valve (V1.2, V2.2, V3.2) for opening and closing the outlet stub pipe; and/or (c) a level indicator (LICA1 , LICA2, LICA3) allowing to determine the maximum reaction mixture level in said ageing reactor; and/or a cooling system.
• the stabilization reactor (R4) is equipped with an inlet for the aged reaction mixture, an inlet for process water, an outlet for the product, and optionally a pump (P) for emptying the stabilization reactor.
• the outlet of the stabilization reactor may comprise a valve (V4.2) for opening and closing the outlet.
• the sulfonation unit can be a cascade system of reactors or a film reactor or any other type known in the art.
• the ageing reactors may be stirred tank reactors, for example those conventionally used in continuous processes, i.e. continuos stirred tank reactors (CSTRs).
• CSTRs continuos stirred tank reactors
• the plant may further comprise a storage container connected to the stabilization reactor (R4) for storing the final product. Also a heat exchanger arranged between the stabilization reactor (R4) and the storage container may be present to cool the product fed from the stabilization reactor into the storage container/vessel.
• the invention also encompasses a method for operating the above plant according to the invention, comprising operating a system of two or more ageing reactors (R1 , R2, R3) in a combined continuous-and-batch manner, comprising the steps of operating the reactors in a continuous unsteady state and batch process conditions, by
• feeding and emptying the ageing reactors may be controlled by means of automatic inlet valves (V1.1 , V2.1 , V3.1 ) and automatic outlet valves (V1.2, V2.2, V3.2) and level indicators (LICA1 , LICA2, LICA3).
• emptying the stabilization reactor may be controlled by means of an automatic outlet valve (V4.2) and/or achieved by means of a pump (P).
• Unit process 1 is the reaction between LAB and S0 3 in which p rosulfonic acid is generated:
• the above reaction runs at a fast rate and, most usually, is conducted in a CSTR type sulfonator or in a CSTR cascade reactor system, or in a film reactor.
• Unit process 2 is the so-called ageing step and is intended to increase the reaction yield. It is connected with the course of the reaction between the previously formed pyrosulfonic acid and any residual uncreacted LAB, according to Eguation (2)
• Process (2) is several dozen times as slow as step (1 ), therefore, it is necessary to separate the reaction and use an additional unit for what is called “ageing" in the form of retention volume.
• part of the pyrosulfonic acid is converted to LABSA as early as in the unit process 1 .
• the sulfonation process is accompanied by undesirable side reactions one of which is the reaction, leading to the formation of sulfones which are impossible to be converted to LABS or eliminated by any steps:
• the sulfones are a component of the free oils fraction and are present at a concentration of ⁇ 1 %.
• Equation (10) which enables determination of the reaction rate constant:
• Fig.1 shows the graph of LAB reverse mass fraction vs. time realationship in the process of batchwise ageing of the reaction mixture. The fit between the curve and the measurement points is good, indicating that the reaction order assumption in the measurement conditions is sufficiently correct.
• Fig .2 shows a simplified diagram of the ageing process strirred tank reactor.
• Material balances for three cases of the reactor's operation were considered in developing an optimum solution for an ageing unit according to the invention, including the batch process reactor, the continuous reactor, and the continuous reactor operated at unsteady-state conditions with accumulation of LAB.
• Equation (19) corresponds to the basic kinetic Equation (9)
• the continuous stirred tank reactor is operated at steady-state conditions for which the rate of accumulation of matter is equal to 0, from which the constant concentration of LAB results:
• Equation (25) provides the following relationship between LAB concentration and average residence time:
• Equation (30) takes the form of a Riccati type differential Equation (32):
• Equation (32) A numerical approach was applied to solving Equation (32) for the purpose of the invention.
• Fig.3. shows the curves of variations of LAB concentrations in time for the following cases: batch process (curve 1 ), prior-art continuous process (2) (dependence on average residence time), unsteady continuous process - filling stage (curve 3), unsteady batch process - ageing stage (curve 4).
• the process of the invention describes a system of curves, comprising curve 3 - point A - curve 4.
• the process is conducted at continuous unsteady- state conditions without taking the reaction mixture from the tank while filling the stirred tank reactor after it was emptied.
• the content of LAB goes down in connection with its conversion, according to Eguation (32), which is shown graphically by curve obtained by solving Eguation (32) numerically.
• Eguation 32
• the inflow of the reaction mixture is stopped and the reaction mixture is aged while the concentration of LAB is reduced along curve described by the following eguation which is correct for a typical batch process: w LAB (33)
• the color indicator for the LABSA obtained according to the invention is much lower (Klett colour 15), compared with the color obtained by extending the residence time.
• the ageing plant of the invention is shown in Fig. 4.
• the plant of the invention comprises a parallel system of 2 or more ageing reactors (R1, R2, R3) and a single stabilization reactor R4 with a working capacity egual to that of the largest of the reactors R1-R3 (or they may have same capacities).
• R1, R2, R3 ageing reactors
• R4 stabilization reactor
• the solution of the invention provides, at this point, for a reactor which is operated in batch process conditions.
• Reactors R1-R3 are fed alternately with a reaction mixture from their common pipeline by means of automatic valves V 1.1., V 2.1., V 3.1. and are emptied alternately by means of automatic valves
• Reactors R1-R3 are eguipped with level indicators LICA1, LICA2, LICA3, respectively.
• the stabilization reactor R4 according to prior-art solutions is fed with a reaction mixture from one of reactors R1-R3 and is emptied using valve V.4.2. and pump P.
• the reactor system's operation i.e., filling and emptying through valves V 1.1. , V 2.1., V3.1., V 1.2., V2.2.,
• V 3.2., V.4.2., pump P is controlled automatically by means of a reaction mixture level indicator system LICA1, LICA2, LICA3 in reactors R1-R3 which are connected with a programable logic control unit.
• LICA1, LICA2, LICA3 reaction mixture level indicator system
• reactors R1-R3 which are connected with a programable logic control unit.
• the solution of the invention provides for the use of two or more reactors being operated alternately so that the reaction mixture from the sulfonation unit, which is operated using a prior-art cascade system of reactors or a film reactor, is fed to the previously emptied tank reactor R1 through a stub pipe with valve V1.1 while valve V 1.2. is closed.
• the first filled reactor (R1 ) is emptied gravitationally at a high rate during approx. 1 min by opening valve V.1.2. so that the emptying time will not disturb the process continuity; the material is sent to the tank of reactor R4 which is fed with such an amount of process water as is indispensable to stabilize the aged reaction mixture and then, after the lapse of time which is indispensable for hydrolysis ( ⁇ 10 min), the material from reactor R4 is sent to the final product tank.
• the amount of water which is indispensable for stabilization is known from prior-art solutions and is ⁇ 2% by weight.
• valve V.1.2. is closed automatically and valve V.1.1. is opened to commence the cycle of filling reactor R1.
• V.2.2. is opened to remove the aged reaction mixture from reactor R2, and valve V.2.2. is closed and, similarly, valve V.3.2 is opened etc.
• the reactor filling and emptying cycles are carried out using a system of level indicators LICA1 , LICA2, LICA3 and automatic valves V1.2 - V3.3. which are connected to the PLC unit.
• the ageing unit operation time diagram of the invention is shown in the form of the Gantt chart in Fig. 5.
• the plant start up procedure is commenced by filling reactor R1 during 0 - 60 min.
• the ageing process in this step runs according to Equation (32) (Fig.3. curve 3).
• ageing of the mixture contained in it is commenced in batch process conditions, according to Equation (33) (Fig.3. curve 4) during 60-178 min; also during that time, i.e., during 60-120 min, the filling of reactor R2 is commenced.
• reactor R1 After the lapse of approx. 178 min the material in reactor R1 is emptied to reactor R4.
• the mixture in reactor R4 is stabilized by introducing water in accordance with prior-art solutions, mixed for 5 min and is then removed through heat exchanger E during approx. 53 min.
• the operating cycle for reactor R1 is repeated for each consecutive reactor, due to which a single batch leaves reactor R4 during every hour of the system's operation while the plant capacity is maintained. Owing to the solution of the invention, after the lapse of the ageing time indicated by the number of reactors, several times as low, near-zero values of LAB concentration are obtained by increasing conversions, higher than those known from prior-art solutions for same residence times.
• Linear alkyl benzene was reacted with sulfur trioxide in a multitube film reactor from BALLESTRA.
• a sample of the reaction mixture from the film reactor was collected to a 1000 mL laboratory reactor tank which was thermostatted and subjected to the ageing process during approx.120 min while stirring intensely.
• the reactor mixture from the film reactor was sent to one of two ageing reactors, equipped with a sampling pipe.
• the process was carried out in a continuous manner at steady-state conditions at a temperature of 50°C, adjusting suitable plant throughputs and volumes of the ageing reactors so as to reach average residence times for the reaction mixture in the reactor tanks in the range

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=49385264

Family Applications (1)

Country Status (2)

Cited By (1)

Family Cites Families (3)

• 2013
  • 2013-10-18 EP EP13779230.5A patent/EP3057938A1/de not_active Withdrawn
  • 2013-10-18 WO PCT/EP2013/071849 patent/WO2015055251A1/en not_active Ceased

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events