SU1167152A1 - Device for automatic control of ammonia synthesis process - Google Patents

Abstract

DEVICE FOR AUTOMATIC CONTROL PROCESS OF SYNTHESIS OF AMMONIA comprising serially connected regulators and actuators on lines purge gas and air into the secondary reformer chromatograph vklyuchayu11i1Y column coupled with a working detector camera comparative detector chamber, which through an amplifier output is connected in parallel to a memory unit, a computing device, and a command device connected to the gas discharge valves and memory blocks, characterized in that, for the purpose of increasing nor is the accuracy of controlling the ratio of hydrogen and nitrogen in the gas at the inlet to the ammonia synthesis column; it additionally contains a source of reference gas, constant and adjustable chokes, while the outputs of the detector’s working and intermediate chambers are interconnected and connected to the first gas discharge valve, the column inlet connected in parallel to the second relief valve and through constant Hbul and adjustable inductors to the gas line at the entrance to the ammonia synthesis column, the output of the first memory block is connected to the air supply regulator, you ( The moves of the second and third memory blocks are connected to the inputs of the computing device, the output of which is connected to the regulator of the purge gas, and the source of the reference gas is connected to the input of the comparative chamber1 1 of the detector .. o:

Description

1.1 The invention relates to the automation of chemical processes and can be used in the industry for the production of mineral fertilizers, chemical - in the systems for controlling the ratio of components in gas mixtures, in particular in the production of ammonia. A device for regulating the ratio of hydrogen and nitrogen in an ammonia synthesis unit is known, comprising an air supply control valve to BTopH4Hbrft reforming associated with the regulator and a thermo conductometric sensor controlling the regulator l. The closest to the proposed technical essence is. a device for automatic regulation of the ammonia synthesis process, containing successively connected controllers and actuators on the purge gas lines and air supply to the secondary reforming, a chromatograph including a column connected to the detector's working chamber, a comparative detector chamber, the output of which is connected to the steam generator memory blocks, a computing device and a command device connected to the gas relief valves and memory blocks z. A common drawback of the known devices is the low accuracy of maintaining the required ratio of hydrogen and nitrogen in the gas at the inlet to the ammonia synthesis column, since it determines small changes in the content of hydrogen and nitrogen at very high concentrations in the gas. The purpose of the invention is to improve the accuracy of controlling the ratio of hydrogen and nitrogen in the gas at the inlet to the column of ammonia synthesis. The goal is achieved by the fact that the known device for automatic regulation of the process of ammonia synthesis, containing sequentially connected controllers and actuators on the purge gas lines and supplying air to the secondary reforming, a chromatograph including a column connected to the working chamber of the detector, a comparative detector chamber, the output of which through the steam amplifier is connected to the memory blocks, computing device and commands2 .2 device connected to the gas relief valves and the block The memory chamber additionally contains a source of reference gas, constant and adjustable chokes, while the outputs of the working and comparative chambers of the detector are interconnected and connected to the first gas release valve, the column inlet is connected in parallel to the second reset valve and through constant and adjustable chokes to the gas line at the inlet to the ammonia synthesis column, the output of the first memory block is connected to the air supply regulator, the outlets of the second and third memory blocks are connected to the inputs of the computing device, the output of which It is connected to the purge gas regulator, and the source of the reference gas is connected to the input of the comparative detector chamber. The above scheme of the device makes it possible to measure only the deviation from the norm of the content of hydrogen and nitrogen in the gas at the inlet to the ammonia synthesis column and, based on the measured deviations, form a regulating influence for the air supply to the secondary reforming. This significantly improves the accuracy of maintaining the ratio of nitrogen and hydrogen in the synthesis column, increases the yield of ammonia, and decreases the amount of unreacted nitrogen and hydrogen pumped with the circulating gas to the inlet of the synthesis column. Fig. 1 is a schematic diagram of the device; Fig. 2 shows a chromatogram and a diagram of the activation of commands that control dump valves and memory blocks. The device contains an actuator 1 on the air supply line. Secondary reforming, air supply regulator 2, chromatograph 3 including column 4, detector 5 with working and comparative chambers and amplifier 6, first and second valves 7 and 8 of the discharge, source 9 of reference gas, constant and adjustable chokes 1 O and 11, safety valve 12, first, second and third memory blocks 13-15, command device 16, computing device 17, purge gas flow regulator 18 and purge gas actuator 19. Column 4 is filled with a sorbent, providing the output of components in the following sequence: H, N., Ar, CHj. The reference gas source 9 contains a mixture of nitrogen and hydrogen in the ratio required for ammonia synthesis. The device works as follows. The first stroke is purging the column 4 with gas from the source 9. Valve 7 is closed, valve 8 is open. The gas from source 9. Passes through the comparative detector chamber, working chamber, column 4 and through valve 8 to the discharge. In this case, the column is saturated with a mixture of nitrogen and hydrogen with concentrations that correspond to their optimum content in the gas at the inlet of the synthesis column. The second cycle is the measurement of the deviated concentrations of the monitored components from the optimal ones. At this time, the valve 7 opens, and the valve 8 closes. Gas continues to flow through the comparative chamber with an optimal nitrogen – hydrogen ratio for discharge through valve 7. The test chamber of the detector 5 and valve 7 will flow controlled gas through the column. If in a controlled gas the ratio of hydrogen to nitrogen is more than optimal, then a nitrogen-hydrogen mixture with a hydrogen to nitrogen ratio corresponding to the controlled gas will flow into the detector's working chamber and after a period of € chambers (Fig. 2). If in a controlled gas the ratio of hydrogen to nitrogen is less than optimal, then the output signal of the Sudet detector corresponds to curve 1 in Fig. 2. Taki the deviation of the ratio of hydrogen to nitrogen from the optimum is measured. The curve presented in Fig. 2 is valid for small deviations of the ratio of hydrogen to nitrogen from the optimum when no separation of hydrogen and nitrogen occurs in the column. In any case, regardless of the ratio of hydrogen to nitrogen, at intervals of time and 2j will be at the detector output signals proportional to the content of n controlled gas and methane, respectively. Depending on the content of methane and argon, the computing device 17 and the controller. 18 form this signal to the actuator 19, which regulates the amount of purging so that the contents of these components are. Comrade corresponded to the specified. The proposed device with an absolutely accurate mixture preparation with an optimal ratio of hydrogen and nitrogen (for example, by decomposing ammonia) allows determining the optimum ratio with an accuracy of up to 10 10% by volume, which corresponds to an increase in the measurement accuracy by an order of magnitude. This allows maintaining the optimal ratios of hydrogen and nitrogen in the ammonia synthesis column with high accuracy, which results in an increase in the yield of ammonia and C1, and the cost of pumping unreacted excess component in the circulating gas

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Claims (1)

DEVICE FOR AUTOMATIC CONTROL OF THE AMMONIA SYNTHESIS PROCESS, containing sequentially connected regulators and actuators on the purge gas and air supply lines for secondary reforming, a chromatograph including a column connected to the working chamber of the detector, a comparative camera of the detector, the output of which through the amplifier is parallel connected to the blocks memory, computing device and command device connected to gas discharge valves and memory blocks, characterized in that, in order to increase the accuracy of In order to control the ratio of hydrogen and nitrogen in the gas at the inlet to the ammonia synthesis column, it additionally contains a reference gas source, constant and adjustable chokes, while the outputs of the working and comparative chambers of the detector are interconnected and connected to the first gas discharge valve, the column inlet is parallel connected to the second relief valve and through the constant and variable inductors - a gas inlet line column synthesis ammi- _Λ aka first output unit 'svya- memory 5 connected to the air supply controller, the second outputs and the third memory blocks are connected to the inputs of the computing device, the output of which is connected to the purge gas regulator, and the source of the reference gas is connected to the input of the comparative chamber of the detector. 1 .1167152