SU947595A1 - Method of regulating process of air separation in cryogenic apparatus - Google Patents

Description

The invention relates to the control of technological processes and can be used in cryogenic technology.

There is a method for regulating the process of air separation in a cryogenic plant by stabilizing the amount of feedstock entering the separation and adjusting the amount of raw materials for the quality and quantity of separation products 1.

However, the implementation of a single method does not provide the specified concentration and flow of oxygen gas while simultaneously obtaining liquid separation products, it is also necessary to use widely adjustable turbo compressors for the implementation of this method in an air separation unit (Performance that is not efficient and not economical to operate on data installations.

The closest in technical essence to the invention is to regulate the process of air separation in a cryogenic plant by changing the cooling capacity of the expander of the flow rate of the liquid separation products depending

from the liquid level in the lower distillation column while maintaining a constant level in the upper column .2.

The disadvantage of this method is to maintain a constant maximum liquid level in the separation apparatus under all modes, which reduces the efficiency of operation.

10 installations in a mode different from the regime with a minimum thermal load, and leads to an increase in energy consumption for air separation.

The purpose of the invention is to reduce the production pressure and reduce the cost of air separation by increasing the control accuracy.

This goal is achieved by the fact that the cooling capacity of the de Thander varies depending on the flow rate, the gaseous products of the air separation, and the flow rate of the liquid U) of the separation products varies depending on the magnitude of the thermal balance. In this case, the magnitude of the thermal unbalance is determined by the increment in the cooling capacity of the expander or by the difference between the amount of cold produced and the total

Claims (2)

30 value cold loss. The drawing shows a scheme for implementing a method for controlling the air separation process in a cryogenic plant. The method is carried out as follows. The air separation unit contains compressor 1, upper 2 and lower 3 distillation columns, condensers 4, .deander 5, concentration regulator of the obtained type acid with executive body 7 and gas analyzer 8 installed on the oxygen gas flow from the upper column, flow regulator 9 received oxygen with a flow meter 10, installed on the flow of gaseous oxygen, the I-13 misalignment device, to the inputs of which current and required amounts of produced oxygen are supplied, respectively Companion body 14, which changes the cooling capacity of the expander, regulates the liquid oxygen flow rate 15 with the executive body 16 and the liquid oxygen flow meter 17, the computational device 18, connected to the device 19, determining the magnitude of the thermal unbalance in the cooling capacity increment and the controller setting 15. The regulator 6 with the help of the executive body 7 keeps the set value of the concentration of the produced oxygen gas. The regulator 9 with the help of the executive body 14 supports the specified value of the flow rate of the produced oxygen gas. The regulator 15 with the help of the executive body 16 maintains the set value of the flow rate of liquid oxygen. Computing device 18 determines the desired target value of the flow rate of liquid oxygen. Thus, when the required amount of gaseous oxygen is changed, the regulator 9 of the flow of produced oxygen in accordance with the error signal of the device 11 with the help of the actuator 14 changes the cooling capacity of the expander 5. A change in the cooling capacity leads to a deviation of the concentration of gaseous oxygen and the regulator 6 of concentration oxygen by means of executive body 7 changes the flow rate of oxygen gas. The adjustment process will continue as long as the current value of the oxygen gas produced becomes equal to the target value. Computing device 19 determines the amount of thermal unbalance in increments of cooling capacity, and computing device 18 determines the increment in consumption of liquid oxygen corresponding to this thermal unbalance and changes the task to controller 15 in consumption of liquid oxygen, which by means of the actuator 16 changes the flow rate of discharged liquid oxygen to required value. Using the proposed method can significantly reduce the loss of gaseous oxygen. By obtaining additional quantities of liquid products. Losses of gaseous oxygen in this case will be reduced by 6-8%. The annual savings from using the proposed method on one air separation plant of the type QAr-30 is approximately 100 thousand rubles. in year. Formula 1. The method of regulating the air separation process in a cryogenic plant by changing the cooling capacity of the expander and the consumption of liquid separation products is also so that, with: the aim of reducing losses and reducing energy consumption for air separation due to increased control accuracy, the cooling capacity of the expander varies depending on the flow rate of the gaseous products of the air separation, and the flow rate of the liquid separation products changes depending on the magnitude, thermal imbalance . 2. A method according to claim 1, characterized in that the amount of thermal unbalance is determined by the increment of the cooling capacity of the expander, 3. The method according to claim 1, which is also distinguished by the fact that the amount of thermal unbalance is determined by the difference between the amount of cold produced and total value of holdopoter. Sources of information taken into account in the examination 1. The author's certificate of the USSR And 266729, cl. B 01 D 3/42, 1967. 2. USSR author's certificate in W 2813581/26, cl. F 25 J 3/04, 1979.