• Weixian Unit 79 Introduction and Different Neutralization System Comparison
    Weixian Unit 79 Introduction and Different Neutralization System Comparison Jul 06, 2023
    1. Description Of Weixian’s Unit 79   1.1 The principle of WEIXIAN’s Unit 79 Neutralization and Dioxane Stripping is that acid and base raw materials alone with 10 times (1000%) cooled, degassed and dioxane stripped SLES to mix and react in the Neutralization Reactor (79MX1). In the reaction, a small quantity of heat is generated which causes a very sight temperature rise (3-5℃). That makes sure the pH value of neutralizing materials is stable and color is light. Meanwhile, the Neutralization Reactor (79MX1) keeps outlet pressure constantly at 0.3 bar, makes the feeding of acid, base, buffer and bleaching agent stable.   1.2 The material that exit from Neutralization Reactor (79MX1) enters the Stripping Tower (79T1). Under vacuum and low temperature condition (45-55℃), the material is evaporating moisture, cooling down, removing dioxane and degassing. Because there is no rotating equipment, and material doesn’t contact with the inner wall of Stripping Tower; maintenance, electric power and cleaning is not required. Also, the duration that material pass from Neutralization Reactor to Stripping Tower is enough for bleaching.   1.3 At the bottom of Stripping Tower (79T1), the material’s (has been cooled, degassed and dioxane stripped) quantity is 10 times of capacity, through 79P6 SLES Recycling pump, goes to Neutralization Reactor (79MX1). So that 79MX1-79T1-79P6 forms the main process line of Unit 79.   1.4 The material (has been cooled, degassed and dioxane stripped) goes through SLES Transferring Pump (79P7) and get discharged from the system. Low temperature steam is condensated by condenser, and the condensated water (contains dioxane) is discharged (200ppm, 75kg/t SLES). The Recycling Vacuum Pump (79P9) creates the vacuum condition.   1.5 Subsidiary materials feeding: the pure water is controlled by a mass flow meter and a adjusting valve (the small adjusting valve is for producing high-concentration product, big adjusting valve is for low-concentration product). The liquid caustic soda is also controlled by a mass flow meter and adjusting valve; buffer and bleaching agents are controlled by metering pumps.   1.6 This system also produces AOS by adopting the bypass of Neutralization Reactor (79MX1) outlet. While producing AOS, Vacuum Pump doesn’t work, the neutralized material doesn’t need to get cooled down, it goes to sultone hydrolysis by Material Pump 79P7.   1.7 The system is under vacuum condition and pH value ≤ 7.5, the temperature rise of neutralization reaction is very less (material temperature ≤ 55℃), and achieves the best producing requirements of SLES ammonium salt.   2. Different SLES Neutralization Technology Comparison   At present, there are four different continuous neutralization technologies exist: 1. Double-step Neutralization of Italian technology; 2. Pump Type Neutralization of American technology ; 3.Vacuum Neutralization of Italian technology and 4. Neutralization and Dioxane Stripping of WEIXIAN.   The former two types are common neutralization technologies, both are using a high-speed shearing mixing equipment to mix the feeding and re-fluent SLES fully, then through a SLES recycle pump and a cooler to remove heat of neutralization. After that, 15 times (1500%) of yield back to neutralization mixing equipment to re-flux, 1 time of yield to product handling. The difference between these two types is: pump type neutralization goes to product handling directly. However, double-step neutralization first go to 2nd mixing equipment to remix, then to product handling. The advantage of these two types is both have a mass flow of SLES re-flux, make the temperature rise lower than 5℃ and pH value stable. According to practical experiences, as long as the SO3 concentration, free oil content and especially the sulphate staying time keep the same, the various indicators will be all the same, such as pH stability and dioxane content.   The latter two types are both multi-function neutralization technologies, integrating neutralization mixing, neutralization cooling, vacuum dioxane stripping and vacuum degassing.   The vacuum neutralization transfers the reaction materials to wiped-film evaporator in which reaction take place. Simultaneously, moisture evaporating, dioxane removing and degassing are conducting under vacuum condition. This technology adopts one wiped-film evaporator for neutralization mixing and moisture evaporation, and the wiped-film evaporator has a limited evaporation area. It is featured in high cost and high motor power consumption and the feeding quantity of SLES is limited. Generally, for a 3.8t/h SLES plant, the valid evaporation area is 10㎡ (without SLES re-flux). If it has 2-3 times re-flux, the valid evaporation area need to achieve 30㎡. Regarding this type of equipment, not only the processing consideration, but also cost and power consumption should be big problems. The vacuum neutralization doesn't has SLES reflux, it will cause too much temperature rise, the material temperature would be more than 85℃ and lead to pH value unstable.    The technology of WEIXIAN’s neutralization and dioxane stripping is mixing reaction material in neutralization reaction pump or mixer fully with 10 times (1000%) SLES re-flux, the temperature rise is controlled at about 3-5℃. Then SLES goes to stripping tower and disperse in it. Simultaneously, evaporate the moisture and degas under -0.09/-0.095 mpa vacuum condition. It achieves neutralizing, cooling, dioxane stripping and degassing at same time, and it overcomes the high temperature rise, poor pH stability and high power consumption of the vacuum neutralization technology. Furthermore, it produces SLES with low dioxane content (guaranteed lower than 10ppm, 1-5ppm is achievable) under higher SO3 concentration (3%) and lower free oil content (1.2%), which means low power consumption, low raw material unit consumption and low dioxane content. WEIXIAN’s neutralization and dioxane stripping technology can be also used for neutralize AOS and SLS.   Regarding common neutralization technology, if the dioxane content achieves below 15ppm, the SO3 concentration would be at 2.3-2.5% and free oil content would be at 1.5-1.7%, which means 15 kWh more power consumption and 3-5 kg more organic raw material consumption for producing every ton of 70% SLES.   3. The advantage of Unit 79 summary   First, in regards of SLES neutralizing, cooling, dioxane stripping and degassing, all the parameters of WEIXIAN’s Unit 79 Neutralization and dioxane stripping is better than Ballestra’s Vacuum Neutralization. Second, with Unit 79, the SO3 content can be raised from 2.75% to 3.75% while sulphnation plant producing SLES, and dioxane and free oil content remaining low value. That means the capacity can be increased max 40%, electric power unit consumption can be decreased 40%, without the need of improving dry air quality.   WEIXIAN’s Unit 79 combines neutralizing, material cooling, degassing and dioxane stripping into one process; produces low/high concentrate sodium/ammonium salt of SLES/SLS, and AOS. Its process flow is short and simple, so that operation is stable and easy. 79T1 is static equipment, without motor or rotating parts, it doesn’t brake. Neutralization reaction take place in 79MX1, with large quantity of slurry recycling, rise of temperature is less than 5 ℃, product’s color and pH value is good and stable. It utilizes the heat of neutralization to evaporate moisture and dioxane under vacuum and low-temperature condition, extra heat from heaters is not required. By achieving low dioxane content, low unit electric power consumption, low organic raw material unit consumption and power consumption, it is the best technology among international competitors’. China Unit 79 Neutralization and Dioxane Stripping, Unit 79 Neutralization and Dioxane Stripping Supplier -
  • Unit 38 Scrubber Waste Water Oxidizing, Evaporating and Crystallizing
    Unit 38 Scrubber Waste Water Oxidizing, Evaporating and Crystallizing Jun 07, 2023
    Process description: The caustic soda waste water (10% solution) from sulphonation would be discharged into 38C1 crystallization tank. 38P1 recycling pump pumps the waste water into 38T1 evaporating tower to evaporate the moisture in that. The temperature would be controlled between 37-42℃, and concentration of salt between 29-33%; it crystallizes itself constantly.   The hot air (≥100℃) for evaporation is from third stage waste heat recovery (68E2/E2). It goes into 38T1 from the bottom to exchange heat with caustic soda liquid, evaporate moisture in it and also oxidize the NaSO3 in waste water to Na2SO4. Temperature of the air exiting 38T1 is controlled at 50℃. Na2SO4 crystal forms in 38C1, drawn by mud pump;then filter and pack. Filtrate goes back to 38C1 crystallization tank.   Unit 38 (caustic soda liquid oxidation, evaporation and crystallization) evaporates the moisture in 10% caustic soda solution, make the salt crystallizes in 38C1 (using the principle that Na2SO4 has different solubilities in difficult temperature. Also, waste heat air is balanced and surplus. Related link: China Unit 38 Waste Water Crystallization, Unit 38 Waste Water Crystallization Supplier -
  • The Advantage Between WEIXIAN's and Italian Sulfonator
    The Advantage Between WEIXIAN's and Italian Sulfonator May 26, 2023
      1. The sealing type of compression nut on reactor tube sheet 1:  increasing one V type Teflon gasket and Fluororubber O ring to isolate the leakage of SO3 and organic acid, so that no rust or leakage happen. The reliability is better than Italy reactor.(as below photo No.1 and 2) 2. The No.3 of photo change to flat Teflon gasket(Italy is two way gasket): This will bring better seal performance and can reduce 50% force to tube sheet 1, so that the transformation would greatly reduced and the organic material would not leak into reactor tube. The reactor washing times and operation period is highly improved.   3. Compared with Italian reactor, the thickness of WEIXIAN tube sheet 1/2/3 is 16% more and organic material chamber is 25% higher, that can make the transformation of tube sheet close to zero and distribution of organic material becomes more equal, this makes big capacity reactor be possible.   4. The welding point between reactor tube and distributor move up to avoid reaction segment and change from butt welding to fillet welding, so that there is no welding joint in reactor tube inside, compared with Italy reactor, WEIXIAN will not have leakage in this part, the reliability improved greatly.   5. The size and angle optimation of reactor tube, distributor and nozzle, make sure the organic material pressure drop 13% more when passing through gap , so the self balance performance is improved accordingly compared with Italy reactor, especially for α-olefin sulfonation.   6. The special manufacture process of reactor tube (without polishing) ,that can make sure the rough degree of tube inside and outside and each tube are highly consistency( Ra0.4), so the dioxane content will significantly superior to Italy’s when produce SLES.   7. One Fluororubber O ring and three Teflon gaskets were adopted between shell side and tube side of tube sheet 3, so WEIXIAN reactor will never leakage, and the cooling water can recycle under 0.5mpa pressure(pressure test is under 0.6mpa)   8. The material of reactor tube, distributor and nozzle are all booked from Bao steel (The biggest and best steel factory in china) and we ordered at least 5 tons one batch, so that the material source can traceable and the quality can be guaranteed.   9. WEIXIAN engineer will full time supervise the testing and assemble of reactor and its components. That will guarantee the fabrication and manufacturing quality.   Equipment Link:  
  • New technology: introduction of reaction heat utilizing for process air dehumidification
    New technology: introduction of reaction heat utilizing for process air dehumidification May 08, 2023
    The cooling, chilling and dehumidifying of process air in the traditional SO3 sulphonation process is to lower the process air to 40 C by recycling cooling water, then further reduce the temperature to 5 C by glycol chilling water solution; then the process air goes to sillica gel air dryers. In this case, the chilling water have to be generated by electrical chiller, for example, a 3.8t/h plant needs a 100KW chiller.   While, the new process Weixian newly developed is using the reaction heats of SO2 from outlet of sulfur furnace and SO3 from outlet of converter to generate steam directly. Minority of the steam goes to sulfur melting and the rest goes to lithium bromide absorption chiller for generating chilling water. The chilling water firstly lower the process air to 8 C and remove majority of the heat; then process air is lowered to 5 C by a 12-15KW electrical chiller. Or, directly lower the process air to 6 C by lithium bromide absorption chiller and directly go to sillica gel drying.   A 3.8t/h plant may save power 100KWH, one year saves about 800,000 kilowatt hour.   Detailed process as following: Air drying unit The fin-type heat exchanger is made out of SS304 and upper part heat exchanging area is 80%. The lithium bromide absorption chiller generates 3 C - 5 C chilling water and lower the process air to 8 C. The lower part of heat exchanging area is 20%, which uses the 1 C glycol solution generated from a electrical chiller to further decrease the the process air to 3 C - 5 C. In the winter, electrical chiller may not need to run. The lithium bromide absorption chiller is driven by 0.4 Mpa steam from waste heat recovery system, equipped with a chilling water tank and pump. The electrical chiller also equips with a glycol solution tank and pump.   Start-up pre-heating Start-up pre-heater is using 400KW electrical heater.   Sulfur combustion and conversion The tubular heat exchanger which in the sulfur furnace SO2 outlet and converter forth pass SO3 outlet have been replaced by fire tube heat exchanger for steam production from waste heat. The steam is generated directly and the efficient therefore has been increased 100%. For example, a 3.8t/h plant when sulfur feeding is 400kg/h, steam production can be 1.4t/h, 0.5 Mpa; when sulfur feeding is 280kg/h, steam production can be 1.0t/h, 0.5 Mpa.    Regeneration The first pass cooler of converter generates 400 C + hot air mix with the 125 C hot air from second SO3 cooler gets 150 C - 180 C hot air, which is used for sillica gel regeneration. The rest hot air is for generating hot water for heat tracing.    Recycling water station Flowrate of recycling water stays unchanged 400m3/h.    External steam supply When plant shut-down, Liquid sulfur tank needs 300kg/h 0.4 Mpa steam and other tanks need hot water for heat tracing.    Start-up pre-heating operation Start-up needs dry air about 2500kg/h and heated by electrical preheater to 450C. In this case, small electrical chiller is able to chill and dehumidify this air, so the lithium bromide absorption chiller is unneeded to work. Sulfur is lighted by electrical lighter. Then SO2 goes into converter (electrical heater is still running) and SO3 temperature increases, and the fire tube heat exchanger start generate steam and drives the lithium bromide absorption chiller, which is also for process air chilling and dehumidifying, until the plant go normal. If there is external steam supply, which can drive the lithium bromide absorption chiller first.    Minimum sulfur feeding flowrate When a 3.8t/h sulphonation plant is running for SLES, minimum sulfur feeding flowrate is 280kg/h, the steam capacity is above 1t/h 0.5Mpa. 300kg/h will be used for liquid sulfur and the rest can guarantee the lithium bromide absorption chiller running normally. A 345KW chilling capacity lithium bromide absorption chiller can be selected, then steam consumption is less than 0.5t/h. Or, if select a 430KW chilling capacity lithium bromide absorption chiller, steam consumption will be less than 0.63t/h, electrical chiller will not be needed in this case.   Surpass steam capacity In case steam production is more than the demand, SO3 first fire tube heat exchanger steam capacity can be reduced by open the bypass and let some heat cooled by the SO3 second cooler whose heat exchange area is increase by 50%. WEIXIAN (NANJING) SCIENCE TECHNOLOGY CO., LTD. China Unit 69 Reaction Heat Recovery, Unit 69 Reaction Heat Recovery Supplier -
  • Innovation and development of SO3 multitube film sulphonation reactor of Weixian
    Innovation and development of SO3 multitube film sulphonation reactor of Weixian Apr 21, 2023
    Innovation and development of SO3 multitube film sulphonation reactor of Weixian Shumin Li, Chen Li, Gongjian Cai (WEIXIAN NANJING SCIENCE TECHNOLOGY CORP. LTD. Jiangsu Nanjing 201142)   Abstract: this article introduces the innovation and experiences of a type of SO3 multitube film sulphonation reactor in its design and manufacturing. Mainly explains the relations among design and manufacturing of reactor’s main parts, sulphonation/sulphoacid reaction, and quality control, production stability and equipment reliability. Concludes that WEIXIAN’s SO3 multitube film sulphonation reactor is superior to similar Italian equipment, in term of key performance and reliability. Key words: SO3 film sulphonation, multitube film sulphonation reactor, innovation, development     Preface: In March 1995, WEIXIAN independently designed and manufactured domestically a 6-tube multitube film sulphonation pilot plant. Its capacity was 250kg/h, and tested LAB, BAB, HAB, FA, AEO and α-olephin as raw material for batch OEM produce. Next, we will introduce WEIXIAN’s innovation and development in regards of SO3 multitube film sulphonation reactor.   1. The reaction tubes of SO3 multitube film sulphonation reactor Since 1995, the first 6-tube film reactor, WEIXIAN always keep improving and perfecting the design and manufacturing process of sulphonation reactor. Basically, the length, internal diameter and thickness influence the heat transfer, material transfer and reaction speed. By countless times experiments, optimal data have been obtained.   The internal tolerance and surface finish difference of reactor tube not only influence heat transfer and material transfer, but also influence differential SO3 and organic material mole ratio, which is crucial for dioxane control when producing SLES. So, while we manufacturing one batch of reaction tubes (normally 1000 tube/batch), we make sure using one mold for the cold working, which ensure each tube’s internal and external diameter tolerance is consistent.   Then the reaction tubes will be putt into a 1040℃ furnace, for removing the stress between molecules due to the cold working. In order to keep the surface finish degree (like mirror) benefit from cold working, there should be no oxygen under this 1040 ℃ condition, which is the most advanced oxygen isolating stress relieving technology. We abandoned the artificial sanding method which can’t make the surface as smooth as mirror. With perfect surface finish degree, side reaction can be reduced effectively, it is crucial in regards of decreasing dioxane content in SLES.   2. Distribution head and SO3 nozzle Please see Drawing 1 for distribution head and SO3 nozzle.   There are special designs for distribution head. The sealing between distribution head and shell side cooling water is able to accept enough pressing force, so that reactor shell can bare pressure up to 0.6 mpa, while the pressure of returning water which enters reactor is normally ≤0.05 mpa. That is why the recycle cooling water is able to carry with higher pressure.   In terms of distribution head and SO3 nozzle processing, we also ensure the consistency, and simplify the first start-up commissioning (see diagram 1 and 2) and extend the interval of reactor cleanings. Especially while producing AOS, the optimizations decrease the lower operation limit of reactor. Because of little feeding volume of α-olephin, the distributing and balancing ability of reactor’s liquid film have to be increased while operating under lower operation limit. Diagram 1  Zhitong system 37-tube reactor first calibration flow rate deviation distribution No. Flow rate deviation Tube quantity Gasket thickness 1 Less than ±1.5% 19 tubes 2.00mm 2 ±1.5%~±2.5% 13 tubes 2.00mm 3 +3.7% 1 tubes 2.00mm 4 -3.6% 1 tubes 2.00mm 5 -5.2% 1 tubes 2.00mm 6 +8.8% 1 tubes 2.00mm 7 -6.5% 1 tubes 2.00mm   Diagram 2  Zhitong system 90-tube reactor first calibration flow rate deviation distribution No. Flow rate deviation Tube quantity Gasket thickness 1 Less than ±1.5% 33 tubes 2.00mm 2 ±1.5%~±2.5% 31 tubes 2.00mm 3 ±2.5%~±3.0% 13 tubes 2.00mm 4 ±3.0%~±3.5% 8 tubes 2.00mm 5 -4.7% 1 tubes 2.00mm 6 +5.6% 1 tubes 2.00mm 7 -8.4% 1 tubes 2.00mm 8 +7.3% 1 tubes 2.00mm 9 +8.9% 1 tubes 2.00mm   As you can see from the diagrams above, the consistent processing of distribution heads and nozzles minimize each reaction tube’s original flow distributing tolerance, and make adjustment easier.   3. Tube sheet and organic material distribution chamber Regarding the tube sheets of 120/144/180 tube reactor, 25% thickness is increased. So that rigidity is increased, tube sheet would not be transformed much and the tightness of SO3 sealing would be improved.   Also, The height of organic distribution chamber is increased by 8-12 mm (see Drawing 1). It is beneficial for large capacity reactor’s organic material distributing.                                Drawing 1                                                Drawing 2     4. The sealing format between SO3 and organic material The increase of organic material distribution chamber height and improvement of shell pressure bearing ability are benefited from the special design of sealing format between SO3 compression nut, tube sheet 1 and tube sheet 2. As Drawing 1, at the top is the first seal of tube sheet 1, that consists of a V-shape gasket (Creep-resistant special teflon) and a O-shape gasket (Anti-oleum fluororubber). That means double safety, each of them ensure 100% isolate SO3 from tube sheet 1’ screw thread and organic material distribution chamber. Therefore, the sealing is very reliable and solved the headache problem that the compression nuts sealing of Italian’s reactor is unreliable, sometimes get rusted and can’t open.   As shown in Drawing 1, the second seal is Z-shape creep-resistant Polytetrafluoroethylene plano-concave gasket, which isolates organic material from SO3 in the nozzle inner wall. This special design is efficient and the locking torque for compression screw heads is only the half of two-direction sealing (which is Ballestra’s, Drawing 2 shows the structure of Ballestra’s distribution head). With only half locking torque, the Tubesheet 1 will has less deformation, especially for big capacity reactors. It solves the problem that after tightening all compression screw heads, you may find the first screw head get loosen again. That consolidates the foundation of design and manufacturing of 180, 192 or even more tube reactors. 
  • Weixian's Neutralization and Dioxane Stripping Process
    Weixian's Neutralization and Dioxane Stripping Process Mar 08, 2023
    WEI XIAN's neutralization and dioxane stripping unit is to mix reaction material in neutralization reaction pump or mixer fully with 10 times SLES reflux. The temperature rise is controlled at about 5℃,then SLES go to stripping tower and disperse in it,at the same time,evaporating the moisture and degassing under -0.09—-0.095mpa vacuum condition. It can achieves neutralization、cooling、dioxane stripping and degassing together, and it overcomes the high temperature rise、poor PH stability and high power consumption of the vacuum neutralization technology. It can produce SLES with low dioxane content(lower than 10ppm)under higher SO3 concentration(3%)and lower free oil content(1.2%),what is called:low power consumption、low unit consumption and low dioxane content. WEIXIAN’s neutralization and dioxane stripping technology can also used for neutralize AOS and SLS. We can supply turnkey project, seperate unit, revamping of old sulphonation plants.
  • What are the main compositions of a LABSA and SLES plant ?
    What are the main compositions of a LABSA and SLES plant ? Apr 14, 2023
    LABSA and SLES Factory Basic Composition  In order to build a LABSA and SLES plant, you will need the following : 1.Land 2. Buildings on the land(like workshop,office....) 3. The basic plant inside of workshop,including equipment,pipeline,PLC,MCC... 4. The storage tanks outside of workshop,including tank,pump,electrical,instrument,pipeline for tank field 5. Cooling tower outside of workshop,including cooling tower,pump,electrical,instrument,pipeline for it 6. The steel structure and platform for plant inside of workshop 7. Laboratory room-Instruments, agents etc 8. Utilities,like power,water,pure water, instrument air,power, water and instrument air 9. Foundation and civil work. 10. Fire proof,Lightning protection 11. Installation 12. Filling machine, weighbridge, storage yield 13. Raw materials for production 14. Paint materials for the pipelines , equipment etc.

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