Fertilizer production Inline analytical technology for: · ammonia · ammonium nitrate · nitric acid · phosphoric acid · sulfuric acid · urea · urea ammonium nitrate Increasing quality, saving resources: LiquiSonic®. With high-value, innovative sensor technology. Robust, accurate, user-friendly. LiquiSonic® LiquiSonic® 3 Increasing quality, saving resources: LiquiSonic®. With high-value, innovative sensor technology. Robust, accurate, user-friendly. LiquiSonic® is an inline analytical system for Integrated temperature detection, sophisticated determining the concentration in liquids directly sensor design, and know-how from SensoTech‘s in the production process. The analyzer is also extensive measurement history in numerous used for phase separation and reaction mo- applications promises users a highly reliable, nitoring. Sensor installation within the product long-lived system. stream means an extremely fast measurement that responds immediately to process changes. Advantages of the measuring method are: · absolute sonic velocity as a well-defi ned and User benefi ts include: retraceable physical quantity · optimal plant control through online and · independence from conductivity, color or real-time information about process states optical transparency of the process liquid · maximized process effi ciency · installation directly into pipes, tanks or vessels · increased product quality · robust, all-metal, gasket-free sensor design · reduced lab costs with no moving parts · immediate detection of process changes · corrosion-resistant by using special material · energy and material savings · maintenance-free · instant warning of irruptions in the process · use in temperatures up to 200 °C (390 °F) water or process liquid · accurate, drift-free measurements · repeatable measuring results · stable measurements even amid gas bubbles · controller connection capacity reaching up to LiquiSonic‘s® ‚state-of-the-art‘ digital signal pro- four sensors cessing technology guarantees highly accurate, fail-safe measuring of absolute sonic velocities · data transmission via fi eldbus (Profi bus DP, and liquid concentrations. Modbus), analog outputs, serial interface or Ethernet Inline process analysis Contents 5 Contents 1 Processes 6 1.1 Ammonia synthesis 7 1.2 Nitric acid synthesis 8 1.3 Ammonium nitrate production 9 1.4 Urea production 10 1.5 UAN production 11 1.6 Phosphoric acid production 12 1.7 Superphosphate production 13 2 LiquiSonic® system 14 2.1 Measuring principle 15 2.2 Customer benefits 16 2.3 Sensor 16 2.4 Controller 16 2.5 Technical specifications 17 6 1 Processes S/H22 S/SO sulfuric acid 6 + phosphate rock + phosphate rock single superphosphate phosphoric acid 7 + phosphate rock triple superphosphate H2 (g) N2 (g) ammonium phosphate ammoniaAmmoniak + O2 (g) + CO2 (g) 1 nitric acid urea 2 4 ammonium nitrate UAN 3 5 Processes 7 1.1 Ammonia synthesis H22 , N , NH3 Ammonia (NH3) is a key ingredient in nitrogen ferti- lizer production. Ammonia also serves as activation material for synthesizing nitric acid and urea for further processing into fertilizers. On an industrial H , N scale, the Haber-Bosch process develops ammonia 22 from the elements nitrogen (N2) and hydrogen (H2) using three production stages: gas production, gas catalytic purification and synthesis. reactor Ammonia formation (N2 + 3H2 2NH3) is catalyzed using iron or ruthenium within the catalytic reactor. Cooling finally condenses ammonia in water solu- tion. In ambient temperatures, the concentration heat exchanger of NH3 typically ranges from 10 wt% to 25 wt%. This can be precisely monitored by the LiquiSonic® 1 analyzer as seen in the graph below. H2 N2 10-25 wt% NH3 LiquiSonic® in the ammonia synthesis process Relationship between sonic velocity and concentration of ammonia in water 8 1.2 Nitric acid synthesis surface to form nitric oxide (NO). Next, NO gas cools to naturally react with secondary air to pre- Nearly 70 % of nitric acid (HNO3) production goes pare nitrogen dioxide (NO2). Lastly, NO2 feeds an toward developing crop fertilizer ammonium nitrate absorption tower to engage counter-flowing water (AN), with the rest used in producing explosives (H2O) to yield nitric acid in typical concentrations of and for the pickling of stainless steel. Nitric acid is 55 wt% to 65 wt% HNO3. This production range formed by the Ostwald process in three stages. can be measured by the LiquiSonic® analyzer as First, a gas mixture of NH3 and air is incinerated shown in the following exhibit. where NH3 reacts on a platinum-rhodium catalytic NH3 O2 NO2 H2 O incinerator oxidation absorption tower towers 1-5 NO, O2 2 55-65 wt% HNO3 LiquiSonic® in the nitric acid sythesis process Relationship between sonic velocity and concentration of nitric acid in water Processes 9 1.3 Ammonium nitrate NH 65 wt% production 3 HNO3 Ammonium nitrate (NH4NO3) or “AN” is one of the most important nitrogenous fertilizers comprising 12.4 % of the world‘s total nitrogen consumption. 32 Beyond agriculture, AN is useful in the production of explosives. Industrial ammonium nitrate is produced almost exclusively by neutralizing NH3 with HNO3 (55 wt% to 65 wt%) to form AN with concentrations of about 70 wt% that can be enhanced to 99.5 wt% by an evaporation process. 3 neutralizer evaporator 3 70 wt% AN 97.7- 99.5 wt% AN LiquiSonic® in the ammonium nitrate production process 10 Urea production occurs in two stages. First, NH 1.4 Urea production 3 and CO2 are heated under pressure to develop Urea‘s (CH4N2O) high nitrogen content makes it ammonium carbamate (CH6N2O2). Second, dehyd- ideal as an agricultural fertilizer and for key roles ration removes H2O to yield concentrations of in pharmacy (e.g. skin care) and chemistry (e.g. 70 wt% to 80 wt% urea – recoverable up to melamine). Urea production follows NH3 formation 98 wt% by evaporation. The graph below depicts ® since Haber-Bosch products – ammonia (NH3) and the LiquiSonic measurement range for this yield carbon dioxide (CO2) – are the required building level with high accuracy. blocks for urea synthesis. NH3 CO2 residual gas reactor decomposer evaporator 34 urea + CH62 N O2 34 70-80 wt% urea 98 wt% urea LiquiSonic® in the urea production process Relationship between sonic velocity and concentration of urea in water Processes 11 1.5 UAN production urea AN Industrial plants that prepare urea ammonium nitra- te solutions (UAN) usually incorporate urea and AN production lines upstream. Typical recipes merge 40 % AN, 30 % urea and water together in a mixing tank. The LiquiSonic® analyzer measures the concentra- tions of reactants and products using a combinati- on of sonic velocity and conductivity. mixing tank + 15 UAN LiquiSonic® in the UAN production process Relationships among sonic velocity, conductivity and concentration of UAN in water 12 1.6 Phosphoric acid production phosphate 70-99.5 wt% Phosphoric acid (H3PO4) is a most important inor- rock H24 SO ganic acid formed by combining phosphate rock (calcium-laden “apatite”) with concentrated sulfuric 36 acid (98 wt% H2SO4). These two components react to yield about 30 wt% phosphoric acid alongside 30 wt% H34 PO the byproduct calcium sulfate (CaSO4). 37 Evaporators can further concentrate phosphoric acid to 54 wt%. As seen below, concentration monitoring of H2SO4 and H3PO4 within this process is favored using the LiquiSonic® analyzer. reactor evaporator 37 CaSO4 54 wt% H34 PO LiquiSonic® in the phosphoric acid production process Advantage of sonic velocity over conductivity and density in sulphuric acid 1860 1560 300 no clear signal 1830 1500 240 density [g/l] 1800 1440 sonic velocity [m/s] 180 conductivity [mS/cm] 1770 1380 120 1740 1320 no clear signal 60 1710 1260 1680 1200 0 80 85 90 95 100 concentration [wt%] sonic velocity conductivity density Processes 13 1.7 Superphosphate production 75 wt% 54 wt% phosphate rock H SO phosphate rock Superphosphates are fertilizers that vary both in 24 H 34PO phosphate wt% and in secondary water-insoluble contents. 36 7 Single superphosphate forms by mixing pulverized phosphate rock with 70 wt% to 75 wt% of H2SO4. Post-reaction solutions solidify a finished product containing 16 wt% to 20 wt% of phosphorus pen- toxide (P2O5). acidulation mixer acidulation mixer Triple superphosphate is prepared with phosphate rock that reacts with phosphoric acid (50 wt% to 54 wt% P2O5). A solid fertilizer with more than double the phosphate content is thus produced (45 wt% to 46 wt% P2O5). The LiquiSonic® analyzer facilitates safe control of critical ranges for sulfuric-phosphoric acid concen- single superphosphate triple superphosphate trations. LiquiSonic® in the production of superphosphates Advantage of sonic velocity over conductivity in phosphoric acid no clear signal 14 2 LiquiSonic® system LiquiSonic® system 15 LiquiSonic® sensing is available in three systems: 2.1 Measuring principle LiquiSonic® 20, LiquiSonic® 30 and LiquiSonic® 40. The LiquiSonic® ultrasonic analyzer can determine LiquiSonic® 30 is a highly efficient device that liquid parameters such as concentration or density, includes one controller with connection up to four as well as being useful for phase separation and sensors that can be installed in different locations. reaction monitoring. The measuring principle is based on the determina- tion of sonic velocity in liquids. The sensor distance (d) between the sonic transmitter and receiver is known, so it is possible to determine sonic velo- city (v) simply by clocking the travel time (t) of the sonic signal (v = d / t). Since sonic velocity depends
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