JPS58185402A - Method for increasing temperature of carbon monoxide converter - Google Patents

Abstract

PURPOSE:To heat up a carbon monoxide converter to a required temperature, by supplying a Co-Mo-Al2O3 catalyst layer with the oxygen-containing gas to be processed, and heating the catalyst layer by the heat of reaction of hydrogen with oxygen contained in the feed gas. CONSTITUTION:When the gas production is interrupted, the temperature of the conversion catalyst layer in the carbon monoxide converter decreases. At the restarting of the carbon monoxide conversion process, the feed gas added preliminary with a specific amount of oxygen is fed to the carbon monoxide converter, and the catalyst layer is heated by the heat of water-producing reaction of hydrogen with oxygen contained in the gas on the catalyst. The oxygen-content of the feed gas is generally about 0.1-5.0vol% preferably about 0.5- 3.0vol%. The oxygen source may be pure oxygen or air. The time necessary to heat up the catalyst layer to the stationary state can be shortened to about 1/3 compared with the conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas generation device equipped with a carbon oxide shift device (hereinafter referred to as a CO shift device), such as a low-pressure catalytic cracking oil gas generator, a hydrocarbon partial combustion gasification device, etc. , a method for efficiently performing CO metamorphosis by quickly raising the temperature of a CO metamorphosis device to a predetermined temperature.

In the following, description will be made by taking as an example city gas production by cyclic cassification and lacite, in which light carbon-hydrogen is first reformed with steam and the resulting organic gas is converted into CO.

It is desirable that the concentration of CO in city gas be as low as possible. The cyclic gasification system, which is operated mainly to meet the demand for city gas during peak hours, is often operated in batches due to its nature, so once the operation is stopped, the catalyst temperature in the CO shift converter will drop. It gradually decreases. Therefore, it usually takes about 3 to 8 hours for the CO shift converter to resume operation and return to the steady state IIK. There is a problem in that the % CO conversion rate is low during the time it takes to return to steady operation after restarting operation, and therefore the CO concentration in the obtained urban waste is low. In order to deal with such problems, conventionally, for example, the following methods have been adopted.

<1) Cover the outer surface of the CO conversion device with an inorganic heat insulating material.

According to this method, even in winter, when the CO shift converter is in use, the calorific value due to the metamorphic reaction, the raw heat difference between the input and output gases of the shift converter (output gas > large gas), and the sum of the heat radiation amount can be balanced. However, when the CO conversion operation is stopped, it is difficult to prevent the catalyst temperature from decreasing due to heat dissipation.

■ Resuming operation For a while, the temperature and load in the reforming reaction will be suppressed and the partial pressure of water vapor will be increased to promote the CO shift reaction, and the resulting reformed gas will reduce CO2.
Heat the O-forming device to raise its temperature. However, this method not only cannot sufficiently reduce the CO concentration in the gas, but also has the disadvantage that it cannot immediately respond to gas demand because it requires a significant reduction in production capacity and is operated under good conditions. be.

(III) Immediately after restarting the operation, gas production is carried out under normal reforming reaction conditions, and the COO formation apparatus is heated and heated by the produced reformed gas. In this method, the CO concentration in the gas is not higher than in case (II) above, and the reformed gas locally heats the catalyst layer in the CO conversion equipment, so the catalyst life is shortened. may be shortened.

As a result of various studies in view of the current situation, the present inventor has determined that when restarting the operation of the co-transformer, the to-be-treated gas containing oxygen is added to the co-No-Al2O3 catalyst layer in the co-transformer. CO
It has been found that the desired high COO conversion rate can be achieved immediately after restarting the operation of the O-coating device. The present invention was completed based on such new knowledge.

The present invention will be described in more detail below with reference to the following.

In the cyclic gasification system shown in Figure 1,
During steady operation, gas or liquid fuel from rice 111 is first mixed with oxygen-containing gas such as air from rice (i) and combusted 12, and then this combustion exhaust gas is sent to the preheating chamber (
7) Heat the checkered shiga inside, and then add the raishi (9)
From the reforming reactor (11) K, the reforming catalyst inside was heated to the temperature K necessary for the reforming reaction.
Exhaust heat recovery boiler 6η, 5 isi (1@ and stack@O
It is then released into the atmosphere. Next, the supply of fuel from the rice cake (3) and air or other oxygen-containing gas from the rice cake (il) is stopped, and water or steam from the rice cake (1) is supplied to the preheater (7) K to perform the reforming reaction. Heating at near conditions <Kt,
This is further fed from the rice cracker (9) to the reforming reactor CIt)K. Reforming reactor (Kawa KFi, naphtha, LPG, light hydrocarbons from natural gas town are supplied from Raishi, N
Steam reforming is carried out in the presence of a known reforming reaction catalyst such as a tO-MgO catalyst.

The reforming reaction conditions are usually a pressure of 1000 to 200 Qam water column, a liquid hourly space velocity of 0.8 to 1.2 At/d/mr1, and an output temperature of about 650 to 900°C. Continuing the reforming reaction When the temperature of the heating device (7) and the reforming reactor (Ql) decreases, heating with the combustion exhaust gas is repeated in the same manner as above. Preheater (7) and reforming reactor (11)
(K), the heating process and the gas production process can be switched as appropriate to continuously produce the gas. The reformed gas from the reforming reactor (+l) is
It enters the exhaust heat recovery boiler 5-UK via line 11, and then enters the KCO transformation unit@ along with the steam from line 40 through the lowered temperature and rice fil.

The reaction conditions in the Co shift converter are also the same as those in the known method, and Co -Mm - is used as the shift catalyst.
Using an Al2O3 catalyst, for example, at a pressure of 1000 to 20
The following conditions are adopted: approximately 00m water column, temperature approximately 280 to 450°C, and space velocity 400 to 80ONnlld 7114 degrees. Output gas from the COO generator (c) passes through line 5 and enters the exhaust heat recovery boiler K, where the heat is recovered and taken out of the system through line 4.

Now, when gas production is interrupted and the COO formation reaction in the COO formation apparatus (c) is stopped, the temperature of the COO formation catalyst layer gradually decreases. In the case of a Co-No-At203 catalyst, when the catalyst layer inlet temperature is less than 250°C, CO
If the metamorphism rate is less than #i70, the CO concentration in the sand and manufactured gas will increase. As is well known, it is difficult and economically disadvantageous to constantly maintain the inlet temperature of the CO shift catalyst bed at 250° C. or higher during the gas production interruption period. Therefore, in the present invention, the inlet temperature of the (?o -No -At203-based CO shift catalyst layer is maintained at least about 150°C (this is easy), and when the CO shift process is restarted, a certain amount of The gas to be treated containing oxygen is supplied to the CO shift converter rz!IK, and the reaction heat generated when the hydrogen and oxygen in the gas react on the catalyst to produce 1 water causes the catalyst layer to be heated. The temperature is raised.The oxygen content in the gas to be treated is
(varies depending on catalyst amount, catalyst layer temperature, etc.), but in order to avoid rapid heating of the catalyst layer, uneven temperature rise, etc. Q
It is more preferably about 0.5 to 3.0 than about voL. The oxygen source may be pure oxygen or air.If the catalyst bed inlet temperature is about 250℃, the CO conversion rate will be 170.
Since it becomes 1 or more, the addition of oxygen to the waste to be treated is stopped. In this way, the heat of the shift reaction increases as the CO shift progresses on the CO shift catalyst with increased activity, and the catalyst bed temperature reaches a steady state within a short time of about 3 seconds compared to the conventional one! IIK returns and a predetermined CO metamorphosis rate can be obtained.

Incidentally, since the CoMo At20- system catalyst requires sulfidation, the gas to be treated entering the CO shift converter (c) is
It is preferable that the sulfur content is about 50 to 500 ppm as H2S.

In the hydrocarbon partial combustion gasification device shown in Figure @2,
Raw materials such as coal and heavy oil are sent from rice fields to a reforming furnace, where they are reformed in the presence of air and steam according to conventional methods.

The high-temperature sludge that leaves the reforming furnace contains positive substances, ash, etc., and these impurities cause trouble in subsequent steps. Therefore, the generated gas passes through the line, heat exchanger ζ3, and line □□□ to the cleaning device @
These impurities are removed by washing with water. The gas that has been washed with water is sent from Raishi I to heat exchanger AK, where it is heated by the high-temperature generated gas from the line.
It is supplied to the CO transformation device f41 via rice cake (b), but the temperature of the waste in the CO transformation device is usually 210
It is about ℃. Therefore, in this case as well, a predetermined amount of oxygen is added in advance to the gas that has been washed with water, and this is supplied to the CO converter 111. Thus, as in the case of the embodiment shown in FIG. 1, the temperature of the catalyst layer can be raised by the reaction heat generated when hydrogen and oxygen in the gas react to produce water. C.O.
The gas leaving the Saisei equipment is sent through line ■ to the usual purification processes such as decarboxylation and desulfurization. Depending on the situation, the material is subjected to treatments such as methanation according to conventional methods.

According to the present invention, the following effects are achieved.

(-1') 5[1t operated intermittently or discontinuously
In the production process, the specified CO
The conversion rate is achieved and gas with low CO concentration is obtained.

10) Since the temperature of the catalyst layer when gas production is restarted may be about 150°C, there is no need to keep it warm by heating unless the interruption period of gas production is particularly long.

Q ~ Even in a continuous operation, when gas is fed into the CO shift catalyst layer, the temperature of the catalyst layer is raised to a predetermined temperature within a short time. There is no need for preheating with a heat exchanger prior to supply, less catalyst is required, and the CO shift converter is smaller.

Example 1 Co-No-A120. A reaction tube with an inner diameter of 50 cm was filled with 800 tons of CO conversion catalyst, and H2S100PP
A predetermined amount of oxygen was added to a steam reformed gas containing t-5/N-) and CO22.5 υoL%, and the mixture was supplied together with steam to the reaction tube to carry out a CO conversion reaction under normal pressure.

The results of examining the catalyst layer weight [1] temperature and CO conversion rate 15 minutes after restarting operation are shown in Table 1 as 1 and 3.

In addition, the 9th result of performing the same CO modification reaction without adding oxygen is shown in the 11th! Meisho and CO metamorphosis rates, shown as Nimu2 and Mu4, were determined as follows.

Table 1 From the results shown in Table 1, the superior efficacy of the method of the present invention is clear.

[Brief explanation of the drawing]

1 and 2 are flowcharts for explaining embodiments of the present invention. (1)...Water or steam supply unit, (3)...
... Fuel supply line, To) ... Oxygen-containing gas supply line such as air, (7) ... Preheater, (River...
...Reforming reactor, -...Light hydrocarbon supply line, Oη...Exhaust heat recovery boiler1. aU...
...Steam supply line, (c)...CO transformation device, (Foundation)...exhaust heat recovery boiler, (311...
・・・Coal, heavy pond raw material supply line, (g)...
...Reforming furnace, -...Heat exchanger, @S...Cleaning device, 4...CO transformation device. (that's all)

Claims (1)

[Claims] - A method for raising the temperature of a carbon oxide shift device, which includes supplying a to-be-treated waste containing oxygen to a co-Me-AL203 catalyst layer in a carbon oxide shift device, and combining hydrogen and oxygen in the scissor gas. A method for raising the temperature of a carbon monoxide shift apparatus, characterized by raising the temperature of a catalyst layer using reaction heat.