Classifications

• • 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
  • B01J19/0006—Controlling or regulating processes
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/10—Devices for withdrawing samples in the liquid or fluent state
  • G01N1/20—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials
  • G01N1/2035—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials by deviating part of a fluid stream, e.g. by drawing-off or tapping
• • 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
  • B01J2219/00004—Scale aspects
  • B01J2219/00006—Large-scale industrial plants
• • 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
  • B01J2219/00168—Controlling or regulating processes controlling the viscosity
• • 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
  • B01J2219/00177—Controlling or regulating processes controlling the pH
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/10—Devices for withdrawing samples in the liquid or fluent state
  • G01N1/20—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials
  • G01N1/2035—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials by deviating part of a fluid stream, e.g. by drawing-off or tapping
  • G01N2001/2064—Devices for withdrawing samples in the liquid or fluent state for flowing or falling materials by deviating part of a fluid stream, e.g. by drawing-off or tapping using a by-pass loop

Definitions

• the present invention relates in general to a method for measuring a plurality of parameters in chemical processes where tempered measurements on liquid media is a requirement and a system therefore.
• the system is particularly suitable for use in resin ) manufacturing.
• monitoring of process parameters of chemical production processes by means of automated operating systems is well-known in the art. Some monitoring systems require human intervention, including manual sampling of the liquid medium for further processing in separate measurements or analysis equipment, possibly in a laboratory remote from the sampling site. These systems are labour-intensive, and the results from them are often not swiftly obtained.
• the measurements are carried out at about the same temperature that prevails inside the reactor.
• the temperature of the medium in these systems is not adjusted.
• the measurement temperature may play a considerable role to obtain accurate results. This is the case when measuring e.g. the viscosity, pH and many other process parameters.
• the viscosity of the reaction medium of a solution of two reactants in a reaction vessel may be very similar at an elevated reaction temperature but fairly different at a lower temperature. The measurement at a lower temperature may then provide more accurate results.
• Non-tempered technology is disclosed in US 6,635,224 illustrating an on-line polymer monitoring apparatus for rapid determination of various polymer properties.
• in-line system refers to a system where a sample flow of a process medium, the parameters of which is to be determined, is passed through a side-loop in which measurement equipment is arranged.
• the temperature of the sample flow will be essentially the same as in the reactor, and is thus not adjusted.
• on-line system refers to a system in which a sample flow of a process medium is withdrawn from the reactor and passed into a closed loop, separated from the reactor, wherein means for tempering the medium is provided, thus enabling measurements to be made at an adjusted and controlled temperature, that differs from the reactor temperature. It has been found that this type of closed loop provides for much more accurate measurements compared to open continuous loops which continuously circulates flow back to the reactor.
• process medium is meant to encompass all reactants taking part or other components or substances present in the reactor where the chemical process is performed such as solvents, solutions etc.
• sample as used herein, is meant a part or fraction of the process medium withdrawn from the reactor used for measurements of process parameters.
• Fig. 1 is a schematic illustration of an automated, tempered combined in-line/on ⁇ line system according to one embodiment of the present invention
• Fig. 2 shows viscosity vs. temperature curves for two resins
• Fig. 3a is a side view of a sieve for use in the system according to the invention
• Fig. 3b is a view from the outlet end of the sieve.
• Fig. 1 shows a system comprising a batch reactor (reactor vessel) 2 in which a manufacturing process of resin is carried out.
• Agitating means 4 driven by a suitable motor is provided in the reactor vessel.
• an outlet 18 is located at the bottom of reactor vessel 2, to which a pipe segment
• a valve V1 is mounted in pipe segment 20.
• Pipe segment 20 is diverted in two pathways by pipe segments 22 and 24 respectively.
• a valve V3 is mounted, and a first loop formed by pipe segments 20 and 22 is completed by a further pipe segment 26, connected to inlet 28 at the bottom of reactor vessel 2, which inlet is preferably not too close to outlet 18.
• a valve V2 is mounted in pipe segment 26 in pipe segment 26, a valve V2 is mounted.
• a means for circulating the sample, preferably a pump 30, for passing sample medium through the system is provided in pipe segment 24.
• Segment 24 is diverted in two pathways by pipe segments 32 and 34.
• a valve V6 is provided in segment 32 .
• Segment 32, 22, 24, and 36 complete a second loop.
• a measurement box 38 is provided further described below.
• the side-loop formed by pipe segments 20, 24, 32, 36 and 26 forms an "in-line measurement loop".
• a third loop is formed by pipe segments 20, 24, 34, 40, 42, 36, and 26.
• a valve V4 and a sieve 44 are provided, the function and design of which will be further illustrated below.
• a heat exchanger 46 for tempering a passing sample to a desired temperature.
• a valve V5 is provided in the segment 42.
• the isolated or separated side-loop formed by pipe segments 22, 24, 34, 40, 42 and 36 will be referred to as an "on-line measurement loop".
• Cooling medium may be passed through heat exchanger 46 via a suitable valve V7 from inlet pipe 50 to outlet pipe 52.
• V7 a suitable valve
• the first loop made up of pipe segments 20, 22, and 26 has no function per se.
• the entire loop system has a capacity of about 40 litres of sample, and is contemplated to be used with a reactor having a volume of 50 m 3 .
• the sample constitutes about 0.08 % of the total reactor volume.
• suitable sensors for pH and viscosity measurements respectively are TBI-Bailey (pH) and
• BTG-KaIIe viscosity
• Other suitable sensors may include e.g. a commercial turbidity sensor such as a Dual Beam Scattered-Light Sensor from Optek-Danulat, GmbH - Essen, Germany as well as NlR spectroscopy equipment for collecting spectrometrical .data from process media, e.g. an lnteractance Immersion System 6500 from FOSS.
• a plate heat exchanger is suitably used to temper the process media.
• Measurement box 38 suitably comprises an elongated tube, in which the sensor/sensors preferably are mounted to measure the temperature of the sample and preferably also to monitor the cooling capacity of the heat exchanger regulating the temperature of the sample.
• Variation in cooling capacity can thus be monitored and cleaning of the cooler may be made accordingly.
• two sensors are mounted in either end of the box.
• a volume change will occur, leading to pressure changes.
• Such pressure/volume changes are preferably adjusted by keeping valve V1 open during the tempering phase.
• the compensators are essentially comprised of rubber elements having the necessary flexibility. These compensators act to reduce vibrations in the measurement box, which is beneficial for the viscosity measurement in particular.
• the means for circulating the sample preferably a pump, may be shut off when the tempering phase has been completed and the measurement of the process parameters is to begin. This is advantageous in the sense that the process parameters, e.g.
• the viscosity, the pH, conductivity, turbidity or spectrometrical data can be measured while the sample is standing still in the pipe segments.
• the sample flow may otherwise, if flowing through the measuring equipment, disturb the measurements and render them less accurate. This may be due to particles dissolved in the sample flow.
• the flow also may cause turbulance, physical forces on the sensor. Further contaminants besides particles, e.g. bubbles, wood chips in certain production lines, can be wholly or partially eliminated. Particles and the like can also be eliminated by means of filter means as further disclosed herein.
• step 1 a pH adjustment is carried out in the beginning of the process (step 1).
• a pH determination is made again during step 2 and initially in step 3 after which the viscosity is measured.
• measurements should be made at 25 0 C, the process temperature in the reactor vessel during the condensation reaction being 9O 0 C.
• step 4 again pH is determined.
• in-line mode For the pH measurements (steps 1 , 2 and 4), "in-line mode" is used. Thereby, the in-line measurement loop defined by pipe segments 20, 24, 32, 36 and 26 is established by opening valves V1 , V2, V6, and closing valves V4, V5, and V3. Pump 30 pumps process medium from reactor 2 through the in-line loop and the medium will thus pass through measurement box 38 where a pH meter is located. The medium is pumped through box 38 for a time sufficient for allowing the pH reading to stabilise. Then the reading is taken as an indication of the pH prevailing in the reactor. .
• the pH meter (not shown as such) is thus located inside measurement box 38.
• glass material comprised in the measurement head of the pH meter is affected by the process conditions, especially the composition of the process medium, and compensations for variations may be made by means of controlling software.
• the "on-line mode" is used for the viscosity measurement (step 3).
• the on-line measurement loop defined by pipe segments 22, 24, 34, 40, 42, and 36 is established by closing valves V1 , V2 and V6, and opening valves V3, V4 and V5.
• the process medium sample is pumped from the reactor into the above defined loop to fill it with the medium to be considered, and when the "on-line loop" defined above is filled, valves V1 and V2 are closed.
• the medium is circulated through the heat exchanger 46.
• the heat exchanger is fed with a suitable cooling medium through inlet 50, until the temperature has reached a desired level.
• the flow of cooling medium may be switched off with valve V7.
• a temperature sensor (not shown) is also located inside measurement box 38. Of course, the pH may be continuously monitored during tempering if desired.
• tempering is especially important for viscosity measurements but also when measuring other temperature sensitive parameters.
• the viscosity differs very little between different substances, which fact is evident from Fig. 2 showing viscosity vs. temperature for two different resins.
• the difference is almost negligible at IOO°C, whereas at room temperature (approximately 20 0 C) 1 the difference is substantial.
• measurements at higher temperatures require extreme accuracy in the equipment to be used.
• Even if the equipment is accurate, the measurement is affected by various phenomena, e.g. vibrations, small solid particles present in the flow etc. These relatively small disturbances may still have a very large influence on the measurements. It has been found that only 1-5 minutes may be required before a reliable measurement can be performed on a tempered sample which enables accurate monitoring. In the process example above, only in-line measurement and on-line tempering/measurement modes were discussed.
• valve V3 is closed and valves V1 and V2 are opened, thereby emptying the loop through reactor vessel inlet 28 and pumping fresh sample into the loop through reactor vessel outlet 18.
• This exchange phase is terminated when the temperature at the inlet 28 equals the temperature at the outlet 18.
• the heat exchanger is preferably inoperative, i.e. valve V7 is switched off to prevent cooling medium to pass through the heat exchanger. At this time, i.e. when the inlet and outlet temperatures equal each other, the system is ready for another on-line mode operation
• non-tempering function when using a sensor with a relatively slow equilibrating time (e.g. pH meter), it may be desirable to isolate a sample flow without tempering it in the heat exchanger. This may be done by closing valves V1 , V2, V4 and V5, and opening valves V3 and V6. Thus, the sample is circulated through the measurement box 38 for a time sufficient for the sensor in question to reach an equilibrium state. This function will be referred to as a "non-tempering function".
• Such cleaning does not form part of the invention per se, and should in fact be tailored for each individual process set up, like an ordinary washing machine setting. Since the various loops for the different measurement modes form sub-loops of the entire side-loop system, and since they are inter-connected by means of a number of valves, it is possible to perform practically instantaneous switching between the various modes, simpiy by opening and closing appropriate valves. As a consequence, the control of a chemical process where a number of different parameters need to be monitored within short time frames is greatly simplified and made much more efficient.
• the process medium is contaminated by small particles, fibres and other debris that has managed to pass the pump without having been comminuted to a sufficiently small size.
• the distance between the plates in the heat exchanger is critical
• the distance is commonly about 4 mm, but may of course vary among different manufacturers.
• a sieve may be provided upstream the heat exchanger. This sieve is not necessary for the function of the system according to the invention, but is primarily provided as a security precaution. However, measurements of e.g. viscosity could be adversely affected by the presence of the mentioned objects in the flow, and thus the sieve may nevertheless be beneficial for the successful operation of the invention.
• the sieve shown in Figs. 3a and 3b, and generally designated 44 comprises an elongated box 54 made of acid proof steel, and has a generally rectangular cross section.
• the mesh structure 62 comprises a mesh 66, mounted in a thin acid proof frame structure (not shown in the figure).
• ridges 70 and 72 on each vertical wall 74 and 76 in box 54.
• the ridges extend from the bottom of the box at the outlet end diagonally upwards to the upper part at the inlet end of the box, and thus, these pairs of ridges form a respective guide means in which the assembly of mesh and frame is inserted through an opening 78

Landscapes

• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Physics & Mathematics (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Health & Medical Sciences (AREA)
• Pathology (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Investigating Or Analyzing Materials Using Thermal Means (AREA)
• Sampling And Sample Adjustment (AREA)
• Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=34933002

Family Applications (1)

Country Status (12)

Cited By (2)

Families Citing this family (1)

Citations (5)

• 2005
  • 2005-09-15 CN CNA2005800347514A patent/CN101039746A/zh active Pending
  • 2005-09-15 CA CA002581850A patent/CA2581850A1/en not_active Abandoned
  • 2005-09-15 EP EP05784657A patent/EP1802391A1/en not_active Withdrawn
  • 2005-09-15 UA UAA200705206A patent/UA83596C2/ru unknown
  • 2005-09-15 ZA ZA200702923A patent/ZA200702923B/xx unknown
  • 2005-09-15 BR BRPI0517544-5A patent/BRPI0517544A/pt not_active IP Right Cessation
  • 2005-09-15 RU RU2007117709/15A patent/RU2372981C2/ru not_active IP Right Cessation
  • 2005-09-15 WO PCT/SE2005/001338 patent/WO2006041372A1/en active Application Filing
  • 2005-09-29 AR ARP050104110A patent/AR054687A1/es unknown
  • 2005-10-06 PE PE2005001181A patent/PE20060808A1/es not_active Application Discontinuation
  • 2005-10-11 MY MYPI20054769A patent/MY138506A/en unknown
• 2007
  • 2007-05-11 NO NO20072403A patent/NO20072403L/no not_active Application Discontinuation

Patent Citations (5)

Also Published As

Similar Documents

Legal Events