EXPERIENCE OF MATERIAL IN FERTILIZERS INDUSTRIES (original) (raw)

The Role of Material in Fertilizers Industries with Energy Saving

www.ResearchGate.net, 2021

In Fertilizers industries the material plays a very important role. Right material can save energy as well as plant life and wrong selection of material may lead to catastrophic failures and outage of plants & even loss of Human lives, Right selection of material leads to long life of plant. In urea plant very corrosive chemicals are used for urea production. The raw material of urea plant is Ammonia and Carbon Dioxide gas which makes very corrosive chemical ammonium Carbamate. For reduced corrosion passivation air is used in reactor as well as stripper according to material of selection different quaintly of air is used. Controlled and less quantity of passivation air is required for Titanium and Zirconium material and hence saving of energy because the huge amount of ammonia is waste with venting of inerts, i.e. saving of energy and environments also. Passivation oxygen given in CO 2 is directly proportional to ammonia losses in MP section. This paper intended how to increase life of urea reactor liner and energy saving with low passivation air and high N/C ratio, Ammonia is the noncorrosive and ammonia to CO 2 Ratio is an important parameter for process optimization occurring less losses and less explosion probability in urea reactor because it affects the amount of produced urea and corrosion to the material in the reactor. Generally we are using urea reactor liner 316L (urea grade), now adopted 2RE69 for large capacity plant (world largest) and Duplex stainless steel.

ENGRO 40 YEARS' EXPERIENCE OF TOTAL RECYCLE UREA PLANT ASIM RASHEED QURESHI & ABDUR REHMAN CHOUDHARY

This paper shares the learning's of Engro 40 years' experience, revamping of urea plant to improve efficiency & capacity, many catastrophic incidents & operational emergencies of total recycle urea plant. Engro's urea-1 plant voyage started from 515MTD urea plant with local ammonia venting without vent stack systems to the EPA and OSHA practiced 780MTD capacity plant with two vent stack systems which is the part of this paper. Under the energy improvement drive engro approached casale trays for their latest design and high efficiency trays for the urea reactor. Rapid and complete depressurization of ammonia reservoir (13met) in the atmosphere without vent stack systems is one the major catastrophic incident in the history of engro which lead to in level-2 emergency. as a result of such incidents engro had gone through a wide-ranging project named large ammonia release (LARA) to handle such incidents in future by making the plant inherently safe. Plant major hardware modifications to make it inherently safe are also part of this paper. Urea plant reactor bulged due to weep-hole leakage which causes plant shut down for 40 days, major learning of this incidents are also part of the paper. Bursting of pressure safety devices during startup & shut down was frequent at urea plant in last 30year's. Reactor pressure during aqua ammonia circulation was reduced to max 1500psig from 3000psig and high pressure loop pressure was also maintained at lower side to avoid pressure safety device (PSD) rupturing and hammering. This paper also covers change in urea plant startup & shut down sop which gives rise to 90% decrease in PSD rupture. A pressure safety device is the last line of defense in case of pressurization of any vessel. This paper also covers many incidents of rupturing of PSD of high pressure decomposer; gas condenser; low pressure decomposer and high pressure absorber cooler, due to abnormal urea plant operations. High pressure decomposer sight glass leakage and

MATERIAL TECHNOLOGY FOR FERTILIZERS INDUSTRIES

www.researchGate.net, 2021

Over the past two decades, the ammonia and urea industry have witnessed spectacular metallurgical developments for process equipment. For example, stainless steels,

IJERT-Urea Plant Equipments Inspection

International Journal of Engineering Research and Technology (IJERT), 2020

https://www.ijert.org/urea-plant-equipments-inspection https://www.ijert.org/research/urea-plant-equipments-inspection-IJERTV9IS030546.pdf There are many equipment's in urea plant which have very important for holding time, partition plate passing, weep holes monitoring, medium pressure absorber, high pressure carbamate condenser, etc.Startup of medium pressure absorber, is one of the most difficult operations of chemical processes in urea plants. In the last few years we have accomplished both theoretical studies and experimental verifications. Perfect sealing of trays by special quality PTFE (Gore-Tax)As a result, significant reduction of startup time period can be achieved by implementing the developed perfect sealing and checking of holding with recommended standard rules. This paper summarizes our recent results from these studies and make standard. Passing rate of partition plate holding check of ferrules. Weep hole monitoring and checking of the leakage through liner in HP vessels. Absorber columns, and trays, can now be designed with a high degree of reliability. Absorber columns have been widely used in the past to separate mixtures of liquids into individual components like ammonia and carbamate mixture. PROCESS DESCRIPTION The urea process is characterized by a urea synthesis loop with a reactor operating at about 140-175 kg/cm2 (g) (for stripping process) with ammonia to carbon dioxide molar ratio at urea reactor inlet of 2.8-3.9. This allows a CO2 conversion into urea of 60-68% in the reactor itself, also perforated trays which prevent back-flow maintained plug flow and favour gas absorption by the liquid. Different type of HET vortex mixture with booster are used now a day to increase the conversion rather than vessel size and pressure. Different types of HET are developed like super cup etc. There are two kinds of chemical reactions at the same time in the urea reactor: 2NH3 + CO2 ↔ NH2-COO-NH4 + 136230 kJ/kmol of carbamate (at 1.03 kg/cm2; 25°C); NH2-COO-NH4 ↔ NH2-CO-NH2 + H2O-17575 kJ/kmol of urea (at 1.03 kg/cm2; 25°C) The First reaction is strongly exothermic and the second one is weakly endothermic and occurs in the liquid phase at low speed. Downstream the urea synthesis the decomposition (and relevant recovery) of unconverted chemical reagents is carried out in three subsequent steps: High Pressure Decomposition in H.P. stripper; Medium Pressure Decomposition in M.P. Decomposer and, finally, Low Pressure Decomposition in L.P. Decomposer. The decomposition reaction is the reverse reaction of the first one above showed, viz.: NH2-COO-NH4 ↔ 2NH3 + CO2 (-Heat) and, as can be inferred from the equation, it is promoted by reducing pressure and adding heat. The urea reactor effluent solution enters the stripper, under slightly lower pressure than the urea reactor, where a fair part of the unconverted carbamate is decomposed, due to the stripping action of either NH3orCO2, so that the overall yield of the H.P. synthesis loop referred to CO2 is as high as 80-85% (on molar basis). Ammonia and carbon dioxide vapours from the stripper top, after mixing with the carbamate recycle solution from M.P. section, are condensed at the same pressure level of the stripper, in the H.P. carbamate condenser; thus producing the LS steam which is used in downstream sections. After separating the inert gases which are passed to M.P. section, the carbamate solution is finally recycled to the reactor bottom by means of a liquid/liquid ejector, which exploits H.P. ammonia feed to reactor as motive fluid. This ejector and the kettle-type carbamate condenser above mentioned, allow a horizontal layout, which is one of the main features of urea process. Downstream of the stripper residual carbamate and ammonia are recovered in two recycle stages operating at about 17.5 kg/cm 2 (g) (M.P. section) and 3.7 kg/cm2 (g) (L.P. section) respectively. Ammonia and carbon dioxide vapours coming from carbamate decomposition are condensed and recycled to H.P. section. The solution leaving the L.P. section arrives to the concentration section where process condensate is removed in order to reach a concentration of about 96-97% which is required to feed granulator. Urea Sections are characterized by the following main process steps: a) Urea synthesis and NH3, CO2 recovery at high pressure; b) Urea purification and NH3, and carbamate recovery at medium and low pressures; c) Urea concentration; d) Waste water treatment. Urea solution production unit is also provided with the following: Auxiliary installation; f) Steam networks; g) Condensate Recovery & Flushing networks.Even if the inspections was made before the first start up, For the inspection of the urea reactor, stripper Carbamate condenser and Carbamate Separator All inspectors were used rubber gasket and a wood cover in order to avoid possible damaging on the gasket seating area of manhole. The weep holes are provided for the following Equipment's: 1. Urea reactor 2. Stripper 3. Carbamate condenser and 4. Carbamate separator IJERTV9IS030546 (This work is licensed under a Creative Commons Attribution 4.0 International License.) www.ijert.org

Design and Development of a Prilled Urea

Agricultural Sciences, 2021

A prilled urea applicator was designed and developed to increase fertilizer use efficiency. The developed applicator’s aims to place Urea continuously at the subsurface of soil between two rows of plants. A line-to-line distance of 20 cm, depth of prilled urea placement of 5 - 7 cm, and field operating condition at 1 - 1.5 cm standing water (for softening the field) was the designed hypothesis. At the laboratory and farm level, test the developed applicator. The applicator consists of a rectangular frame, two skids and furrow opener, two cylindrical hoppers, and a drive wheel connected with a metering device. The designed applicator was fabricated using PVC, except the push handled (mild steel). The metering device consists of twelve spikes and is made of a metallic plate to apply the Urea uniformly. The applicator has a furrow opener and closer options. The effective field capacity was 0.13 ha/h with a speed of 1.22 km/h and field efficiency of 98%. Due to the continuous falling mechanism, there is no missing option but found the over-falling urea for both hoppers was found 5.35%. The average depth of urea placement was 6.38 cm. The machine was user-friendly to push, and the mean pushing force was 63.89 N. The weight of the applicator was 9 kg. So, it is natural to carry from one field to another field. The applicator is also convenient to handle, operate and manage.

Discussion on Urea Product Quality

www.researchgate.net, 2011

Dear friends today we will discuss on urea product quality. What are the factors on which urea product quality depends? How to improve urea product quality. Urea produced by prilling and granulation rout. In India Prilling is very popular and other countries Granulation rout is adopted. There are some merits and demerits are prilling and granulation routs. Different types of question with their answers. Keywords Urea, product, Biuret, Moisture crushing strength, prilling, Granulation Q.-1-How much loss from Natural prilling Tower? Ans.-1.20-1.50 t/Day or 50-62.5 kg/hr from prilling tower top as a fine urea dust. Q-2-How air flow varies into the prilling tower? Ans.-The air flow is the function of temperature. In summer season the air flow increased as per temperature. Q-3-How much air required per ton of urea in Prilling tower flow? Ans.-about 1150-1200 Nm3/ton of urea. Q-4-How to calculate? Ans.-Suppose for 3850 TPD Plant or 160.4 T/ day Urea production-3850 Tones i.e., 160.4 T/Hr (1)Enthalpy of urea solution=160.4x10 3 x0.321x132.6=6.810x10 6 K.Cal