Yara International

The present disclosure provides a method for operating a urea plant comprising an urea synthesis section, wherein the synthesis section comprises at least one high-pressure process line, a flushing system fluidly connected to the at least one high-pressure process line, a first high pressure flushing pump configured to direct an aqueous solution to the flushing system, and at least one sensor for measuring a process variable, wherein the urea plant comprises a second high-pressure flushing pump configured to direct an aqueous solution to the at least one sensor for measuring a process variable, and wherein the method further comprises continuously directing an aqueous solution from the second high-pressure flushing pump to the flushing system. The present disclosure further provides an assembly comprising a flushing system, a first high pressure flushing pump fluidly connected to the flushing system, a second high-pressure flushing pump and at least one sensor for measuring a process variable in the synthesis section, wherein the second high-pressure flushing pump is fluidly connected to the flushing system and to the at least one sensor and configured to provide an aqueous solution to the flushing system and to the at least one sensor.

A computer-implemented method for asset identification and modeling, the method comprising: - receiving asset information data and asset operating data; - defining operating states of the asset and identifying faulty periods of the asset based on the received asset information and asset operating data; - selecting non-anomalous operating data of the asset; - training at least one model configured to detect asset anomalies based on the selected non-anomalous operating data; - validating the at least one model; - determining an asset anomaly based on the asset current operating data and on at least one of the validated at least one models.

The present disclosure relates to a process for production of nitric acid and a nitric acid production plant, particularly wherein a tail gas recycle stream is supplied to the converter. More in particular, in the process and plant of the present disclosure, at least part of the tail gas is treated in a tail gas treatment section and further heated in a heating section, thereby obtaining a heated tail gas stream, typically having the temperature in the range of 400-600°C. The temperature of this heated tail gas stream is reduced by mixing with a tail gas bypass stream bypassing the tail gas treatment section and/or heating section, resulting in the tail gas recycle stream that can be recirculated to the converter and having the correct temperature for the converter, typically having a temperature in the range of 150-300°C. The disclosure further provides the use of the nitric acid production plant for performing the method according to present disclosure and the method of revamping a nitric acid production plant.

The present disclosure provides a method for measuring the biuret content of an aqueous solution comprising urea, one or more ammonium salts, free ammonia, and biuret, the method comprises: passing a first aqueous solution comprising urea, one or more ammonium salts, free ammonia, and biuret, through an ion exchange column comprising acid groups with a pKa ranging from 3.0 to 5.0, thereby obtaining a second aqueous solution comprising urea, one or more ammonium salts, and biuret and depleted in ammonia; analyzing the second aqueous solution in a system comprising a high-performance liquid chromatography device, thereby measuring the biuret content of the second aqueous solution; and processing the biuret content of the second aqueous solution, thereby obtaining the biuret content of the first aqueous solution.

The present disclosure relates to a method and a system to increase the dissolved oxygen content in a water body having a dissolved oxygen content of between 0 mg/l and 4 mg/l, or to anticipate a future drop of a dissolved oxygen content of a water body to between 0 mg/l and 4 mg/l, wherein the water body is non-stratified, or is stratified and comprises at least an epilimnion, wherein the method comprises a step a, wherein a stream of diluted aqueous nitrate containing liquid droplets of which at least part are diluted oxygenated aqueous nitrate containing liquid droplets are formed, and a subsequent step b, wherein the diluted aqueous nitrate containing liquid droplets of which at least part are oxygenated diluted aqueous nitrate containing liquid droplets are further spread, in case of a non-stratified water body, in a part of the water body or in the whole water body, and in case of a stratified water body, in a part of the epilimnion of the water body or in the whole epilimnion of the water body.

The present disclosure relates to a horizontally oriented gas handling equipment of a chemical production plant, comprising a bottom with a lowest part, and being configured to receive a gas which comprises solid particles, wherein, during operation, the solid particles at least partially are carried over from the gas phase to a condensate phase, and comprising a drain arrangement located in the lowest part of the bottom of the gas handling equipment, which comprises a drain nozzle comprising an drain opening, and a drain pipe which is in liquid communication with the drain nozzle, the drain opening being configured to drain the condensate out of the gas handling equipment towards the drain pipe, and wherein a collar which at least partially surrounds the drain opening and comprises one or more collar drain openings which are located in a side of the collar opposite to the flow direction of the incoming gas in the gas handling equipment, at least part of the solid particles of the condensate being stopped by the collar, thereby obtaining a remaining part of the condensate with a reduced amount of solid particles which will flow towards the one or more collar drain openings, and subsequently in the nozzle opening and finally in the drain pipe. The present disclosure further relates to a nitric acid production plant comprising an ammonia oxidizer, an absorption tower, and horizontally oriented gas handling equipment. The present disclosure finally relates to a method for handling a gas with solid particles in a horizontally oriented gas handling equipment of a chemical production plant.

The present disclosure relates to a gas handling equipment of a chemical production plant, comprising a bottom with a lowest part, and being configured to receive a gas which comprises solid particles, wherein, during operation, the solid particles at least partially are carried over from the gas phase to a condensate phase, and comprising a drain arrangement located in the lowest part of the bottom of the gas handling equipment, which comprises a drain nozzle comprising an drain opening, and a drain pipe which is in liquid communication with the drain nozzle, the drain opening being configured to drain the condensate out of the gas handling equipment towards the drain pipe, and wherein one or more floating ball liquid traps are installed downstream the one or more drain arrangements, each floating ball trap being configured to evacuate the condensate out of one or more of the drain pipes when condensate is present in the drain pipe of the respective drain arrangement(s). The present disclosure further relates to a nitric acid production plant comprising an ammonia oxidizer, an absorption tower, and gas handling equipment. The present disclosure finally relates to a method for handling a gas in a gas handling equipment of a chemical production plant.

The present disclosure relates to a heat exchange arrangement comprising one or more shell and tube heat exchangers having a shell with an inner space, the heat exchanger having a tube-side inlet which enters a tube-side fluid to be heated or cooled in a front head located in between the tube-side inlet and a front tube sheet, from which the tube-side fluid then is distributed to a plurality of tubes which are held in place by tube sheets, and through which the tube-side fluid moves and during the movement is cooled or heated by a first shell-side heating or cooling fluid which moves through a first compartment with a first compartment inlet and a first compartment outlet, and by a second shell-side heating or cooling fluid which moves through a second compartment with a second compartment inlet and a second compartment outlet, whereafter the cooled or heated tube-side fluid is collected in a rear head located between a rear tube sheet and a tube-side outlet through which the cooled process gas leaves the heat exchanger, the tubes further being supported by a first and a second intermediate tube sheet placed between the front tube sheet and the rear tube sheet and between which a buffer compartment is formed with a buffer fluid with a buffer fluid temperature, the buffer fluid not chemically reacting producing insoluble compounds that precipitate as scale and not comprising compounds that chemically react with the shell resulting in corrosion at the buffer fluid temperature, and having a pressure which is higher than the higher one of the pressure of the first shell-side fluid in the first compartment and the second shell-side fluid in the second compartment.

A burner basket assembly of an ammonia oxidation reactor, wherein the burner basket assembly comprises a burner basket inner side wall, a gas-permeable bottom plate, wherein between the burner basket inner side wall and the bottom plate a circumferential radial clearance is present, an L-shaped clearance cover profile which comprises a horizontal and a vertical clearance cover plate, wherein the horizontal and the vertical clearance cover plate are mechanically fixed to each other, wherein the vertical clearance cover plate comprises a window opening, and wherein the L-shaped cover profile during operation is displaceable in a vertical direction in view of the burner basket inner side wall, and at least one key-lock system which comprises a lock which is connected to the burner basket inner side wall, which extends through the window opening in the vertical clearance cover plate, and which comprises at least one lock opening, and a key which has at least a vertical pin with a certain pin length, wherein the lock opening is configured to allow insertion of the pin in the lock opening, and at the same time is configured to limit movement of the pin in view of the lock opening to such an extent that radial movement of the vertical clearance plate in view of the burner basket inner side wall is restricted.

The present disclosure provides a pressure control valve (1), in particular for use in a urea-producing plant. The present disclosure also provides a urea-producing plant comprising one or more pressure control valves (1), and the use of a pressure control valve (1) in a urea-producing plant. The pressure control valve (1) comprises a first body part (2) and a second body part (3) fluidically connected to each other through a valve seat (8), wherein the first body part (2) comprises an inlet (4) and a flow-regulating component, the movement of which regulates the volume flow rate of fluid flowing from the first body part (2) to the second body part (3); the second body part (3) comprises an outlet (5); the first body part (2) and the second body part (3) are made from the same first material; wherein the valve seat (8) has a cylindrical shape and circular walls and comprises an inner region (10) and an outer region (9), and wherein the outer region (9) is made from a second material, the inner region (10) is made from a third material, and the second material has a lower hardness than the third material.