JPS60187323A - Removing method of hydrocarbon - Google Patents

Abstract

PURPOSE:To reduce amount of remaining oxygen by detecting flow rate of gaseous starting material and quantity of heat for combustion of hydrocarbon in removing method of the hydrocarbon, computing the amount of gaseous oxygen to be added from the detected value and controlling the amount. CONSTITUTION:One part of gaseous starting material is collected in a calorimeter 7 and hydrocarbon which is combustible components is burned to measure the quantity of heat on this occasion. The detection signal Q of the calorimeter 7 and a flowmeter 6 of gaseous starting material is inputted to an arithmetic unit 2 and the amount of gaseous oxygen to be added is computed on basis of these detection signals. The signal showing feed rate F0 of gaseous oxygen computed in said unit 2 is supplied to a gaseous oxygen controller 4 as control command and a control valve 3 is adjusted by the controller 4 to control oxygen flow rate. Further, the detected value of an analyzer 5 is inputted to the arithmetic unit and the feed rate of gaseous oxygen is controlled so that the concn. of the hydrocarbon becomes less than predetermined value. By this way, the hydrocarbon is removed at a catalyst tank 1 and the remaining oxygen is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a hydrocarbon removal method for removing hydrocarbons from a raw material gas.

[Background of the invention]

In argon recovery equipment and the like, pretreatment is performed to remove hydrocarbons contained in the raw material gas.

As a method to remove hydrocarbons.

By passing a gas prepared by adding ultiple gas to the raw material gas through a catalyst tank filled with palladium, etc., the hydrocarbons contained in the raw material gas are reacted with oxygen in the catalyst tank to generate carbon dioxide gas and water. Oxygen gas is generally added in excess to completely remove hydrocarbons. Note that the carbon dioxide and water produced are The raw material gas that has passed through the catalyst tank is supplied to the adsorption tower, where it is adsorbed and removed.
When excessive oxygen gas is supplied to remove hydrocarbons, in argon recovery plants, argon and residual oxygen must be separated from each other in a side tank, and in such plants, the amount of residual oxygen must be reduced (usually below IPPM). ) It was necessary. Therefore, the amount of oxygen gas added must be controlled to an appropriate value. FIG. 1 shows an example of conventional control.

This will be explained with reference to FIG. Hydrocarbons contained in large amounts in the N source gas are CH4e CgH6+ C3H6.

In the example shown in FIG. 1, the CH4 concentration that reaches the highest temperature when combusting with oxygen at the outlet of the catalyst tank 1 is detected by the analysis recorder 5, and the raw material gas flow rate is detected by the raw material gas flow rate ill.
Based on these, the oxygen gas supply amount is determined and controlled so that the CH4 concentration at the outlet of the catalyst tank 1 is below a predetermined value (usually below 0.1 mo). That is, the calculation device 12 calculates the oxygen gas supply command, and the oxygen gas regulator 4 is controlled by adjusting the control valve 3 with the 20 fingers. In the example shown in Figure 1, only the CH4 concentration is controlled to be below the set value, so when the CH4 concentration falls below the set value, other hydrocarbons C2H6, C
The problem is that there is no control regardless of the concentration of 3H8 and the like.

In the example shown in FIG. 2, analytical recorders 7, 8, and 9 are installed to detect the respective concentrations of hydrocarbons expected at the inlet of the catalyst tank 1, and these detected values and feedstock gas flow rate meters are installed. 6
Based on the detected value, the amount of oxygen gas co-supplied that makes it possible to reduce the hydrocarbon concentration to a predetermined concentration is determined and controlled. In this example, compared to the one in Figure 1, the concentration of each type of hydrocarbon is determined and reflected in the calculation of oxygen gas supply 'M (oxygen gas supply command), allowing for more detailed control. There is a possibility that it can be done. However, in the case of FIG. 2, there remains the problem that it is disadvantageous in terms of cost, and that the optimal oxygen gas supply amount for each hydrocarbon component does not necessarily match, and in the end, it is only possible to control them according to the greatest common divisor.

[Purpose of the invention]

An object of the present invention is to provide a method for removing hydrocarbons that can reduce the amount of residual oxygen by removing at least the amount of hydrocarbons.

[Summary of the invention]

The present invention is characterized in that the raw material gas flow rate and the amount of heat generated when hydrocarbons in the raw material gas are combusted are detected, and the amount of oxygen gas to be added is determined and controlled based on the detected values. .

[Embodiments of the invention]

The present invention will be explained below with reference to an embodiment shown in FIG. In FIG. 3, 1 is a catalyst tank, 2 is an arithmetic unit, 3 is a control valve, 4 is an oxygen gas regulator, 5 is an analysis recorder, 6 is a raw gas flow meter, and 7 is a calorimeter.

The calorimeter 7 detects the amount of heat generated when hydrocarbons in the raw material gas are combusted.

A part of the raw material gas is collected in the calorimeter 7, and the combustible components, hydrocarbons, are burned, and the amount of heat at that time is measured. This measurement value is per unit amount of raw material gas (INm"/H). For example, when hydrocarbons in raw material gas are
, C3H, the amount of heat Q detected by the calorimeter 7 is
is the sum of these.

That is, CH4+202 →C02+2 H20+ Q 1 ・
...(1)02N(6+T02→2CO2+3H
20+Q2 town/cutting) c3as+5og =3CO2
+4H20+Qs +・+・el)Q = Qt +
Q 2+ Qs ・Old...(4) However, Ql; CH4
Reaction heat amount Q2; Reaction heat amount Qs due to C2H6; Reaction heat amount Qs due to CaHs. Since the amount of heat generated by combustion per unit amount of each hydrocarbon component is constant, the amount of heat measured by the calorimeter 7 is proportional to the hydrocarbon concentration. The calculation device 2 is this calorimeter 7
and the detection signal Q of the raw material gas flowmeter 6 are input, and the amount of oxygen gas to be added is calculated based on these detection signals. The calculation formula is performed, for example, by the following formula.

, 4 FO”” (Q/Qls) X 2 X FoX f
・=-(51 Here, Fo: Added oxygen gas flow rate (oxygen gas supply amount) FG: Raw material gas flow rate f; Flow rate correction coefficient In this equation (5), Qllll is when a large amount of CH4 is included. It is the amount of heat due to CH4 which is the standard,
This is the setting value. f is a correction coefficient to prevent added oxygen from becoming surplus to hydrocarbons, and usually f is 0.
The value is about 9 to 0.95. A signal representing the oxygen gas supply amount Fo calculated by the calculation device 2 is supplied to the oxygen gas regulator 4 as a control command.

The regulator 4 thereby regulates the regulating valve 3 and controls the oxygen flow rate. Note that the calculation device 2 inputs the detection value of the analysis recorder 5, and if the detected value exceeds the scheduled concentration, adjusts the oxygen gas supply amount so that the hydrocarbon concentration becomes below the scheduled value. Specifically, adaptive correction control is performed to correct the calculated value of Fo in Equation 51 in an appropriate direction and in an increasing direction.

According to this embodiment, even if there are many hydrocarbon components contained in the raw material gas, it can be handled with one calorimeter 7.
The configuration is simple. It is also advantageous in terms of cost. In addition, since the oxygen is detected before being supplied to the catalyst tank 1 and controlled to have an appropriate amount of oxygen, responsiveness to fluctuations in the raw material gas is good.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to reduce the amount of residual oxygen and remove hydrocarbons.

[Brief explanation of drawings]

FIG. 1E1 and FIG. 2 are diagrams for explaining a conventional hydrocarbon removal method, and FIG. 3 is a diagram showing an embodiment of the present invention. 1... Catalyst tank, 2... Arithmetic device, 3... Control valve, 4... Oxygen gas regulator,
6... Raw material gas flow meter, 7 Figure 1 Diagram 2

Claims (1)

[Claims] 1. In a hydrocarbon removal method in which oxygen gas is added to the raw material gas and the gas is supplied to a catalyst tank to remove hydrocarbons in the raw material gas, the flow rate of the raw material gas and the amount of heat generated by the combustion of the hydrocarbons are measured. A method for removing hydrocarbons, comprising: detecting a carcass, and controlling the amount of oxygen gas based on the detected value of the carcass.