JPS59199501A - Hydrogen production method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improvement in the production method of hydrogen of various grades required industrially. In this case, the present invention provides a process that can produce hydrogen at low cost.

Conventionally, when trying to obtain hydrogen from hydrocarbons, the typical methods used are as follows.

(a) Desulfurization-steam reforming m-high temperature conversion of carbon oxide-/l
Low temperature conversion - decarbonation gas - methanation (1) Partial oxidation - carbon oxide high temperature conversion - horn Low temperature 1st conversion - carbon dioxide - desulfurization - methanation (C) Desulfurization - steam reforming m - high temperature conversion of carbon oxide ( -II Low dry conversion - Pressure fluctuation adsorption method (a) The lifting platform where the feedstock hydrocarbon contains sulfur is first
2 sulfur. Next, it is subjected to external heat steam reforming.

Most of the hydrocarbons undergo a reforming reaction, resulting in a mixed residue containing hydrogen and carbon monoxide as main components. The carbon monoxide is then converted to hydrogen through a conversion reaction.

-For the carbon oxide conversion reaction, there is a high-temperature conversion in which the reaction is carried out at about 400'C using an iron-based catalyst, and a high-temperature conversion in which the reaction is carried out at about 200 to 230'C using a copper-zinc based catalyst. -The final conversion of carbon oxide
If the desired temperature is about 2-4%, only high-temperature conversion is used; if the desired temperature is 1% or less, a combination of high-temperature conversion and low-temperature conversion is used. 3. Next, carbon dioxide gas is removed from the residue. Although a small amount of -carbon oxide and carbon dioxide remain in the gas,
Since these are often poisonous or harmful to catalysts, they are converted to methane through a methanation reaction.

In this case, the hydrogen temperature is about 97-98%, and the main impurities are methane, nitrogen, etc.

(b) is often used in the case of heavy hydrocarbons as the Totomihara slope.

For example, in the case of medium oil, oxygen is used for partial oxidation.
Becomes a recusant.

After that, the process is almost the same as in <a>.

(a) and (b) are done in the usual way, but]
There is a disadvantage that the number is large, and therefore the blunt cost is relatively high. Furthermore, it is impossible to achieve a hydrogen purity of 97 to 98% or higher.

Method (C) is a relatively recently developed technique.

Pressure fluctuation adsorption (PSA) utilizes the selective adsorption property of an adsorbent and changes the pressure of the gas to adsorb the gas onto the adsorbent, deattribute it to C, and separate the gas.

It is especially effective in poems that separate hydrogen from mixed hydrogen scum. That is, gases that normally form a gas mixture with hydrogen, such as nitrogen, argon, carbon oxide, carbon dioxide, and hydrocarbons, are effectively separated, and 1 q of extremely pure hydrogen can be produced.

Note) Pressure fluctuation adsorption method - PSA
reSwingAdsorption) Before the development of this pressure swing adsorption method, hydrogen production methods were either (a) or (b). That is, either external heat steam reforming or internal heat reforming using partial oxidation was used. A process that combines both has been used in ammonia production for some time, but has not been used in hydrogen production plan 1. This is probably because the partial oxidation internal thermal method using air introduces nitrogen into the gas, making it uncomfortable, and the partial oxidation internal thermal method using C oxygen increases the cost.

Although method (C) is a new method, it still uses a combination of external heat type and internal heat type as the reformer.
There are no examples. As will be explained later, in the pressure fluctuation adsorption method, hydrogen can be selectively separated, so even if nitrogen enters the gas or λ, it can be completely removed, so it is not a problem. This combination has the highest Ic thermal efficiency.

With the development of the pressure-horn adsorption method, the scale of hydrogen plants that use it has also increased, and energy consumption has become particularly strict recently.

With this invention we provide, it is possible to produce high-purity hydrogen in large quantities at low cost.

To summarize the main points of our invention, we can use this steam reforming method for heavy hydrocarbons: primary reforming, that is, ordinary external heat steam reforming, and secondary reforming, that is, oxygen, oxygen-enriched air, or air. Internal thermal partial oxidation or steam reforming using hydrogen is carried out in two stages to produce a hydrogen-rich 7J gas, which is subjected to a carbon oxide conversion reaction and then treated by a pressure fluctuation adsorption method.
It's located where you are.

When producing hydrogen using carbon or hydrogen carbon as raw materials, it is first necessary to create a gas containing a large amount of hydrogen through reforming or partial oxidation. Light hydrocarbons, such as hydrocarbons lighter than straight-run naphtha, are gasified by steam reforming.

It is also common practice to gasify heavy hydrocarbons using oxygen, oxygen-enriched air, or air.

Our method begins with steam reforming of heavy hydrocarbons.

External heat steam reforming of heavy hydrocarbons was generally considered impossible due to carbon deposition, but the development of an appropriate catalyst has made it possible.

That is, "Production method of hydrogen-rich gas" (Patent No. 106812)
As is clear from 3), it has become possible to gasify heavy hydrocarbons such as vacuum distillation residual oil by external heat steam reforming.

By using this method, heavy hydrocarbons such as crude oil and heavy oil can also be treated, and use +3;
By expanding the types of r3+, there is a possibility of improvement in accumulation property.
Iq′tJ for secondary reforming or partial oxidation using oxygen-enriched air or air. The resulting high temperature causes a significant decrease in C meta2 and an increase in H2+CO. The thermal efficiency of a plant for obtaining hydrogen is highest when the primary reforming is followed by the secondary reforming or partial oxidation. The low cost of raw materials and this high thermal efficiency make the price of hydrogen the most attractive. This means that in some cases, no oxidizing agent is added.

According to the inventor's research, this primary reforming reaction has a high temperature, so even if the gas is directly introduced into the secondary reforming reactor, a considerable reforming reaction will occur due to its own sensible heat. This is because it has become clear.

Therefore, in professional wrestling, it is possible that no oxygen-containing gas is added at all.

The gasified residue then undergoes a carbon monoxide conversion reaction.

Since the pressure fluctuation adsorption method can cope with slight fluctuations in carbon monoxide without any problems, the extent to which carbon oxide can be removed depends on the hydrogen cost calculation.

After this, the gas is immediately subjected to the pressure fluctuating suction method (=I), but in some cases carbon dioxide may be removed.An example of removal is when carbon dioxide is required for a urea plant. In other words, the hydrogen produced here is converted to ammonia and then to urea.The reason for separating carbon dioxide is that it is not necessary to separate hydrogen in the subsequent pressure horn fluctuation adsorption step. It has a positive effect. In other words, by removing carbon dioxide, the hydrogen separation efficiency increases slightly. It also has the effect of increasing the heat generation (jl) of the exhaust gas from the pressure fluctuation adsorption device. However, it is not used when it is especially necessary for urea etc. There is no need to remove carbon dioxide, and the cost of -C is usually the lowest if the hydrogen is removed as is using a pressure fluctuation adsorption device.

(31) The hydrogen is then separated from the gas by pressure swing adsorption. The impurity gases other than hydrogen are nitrogen, ergone, methane, -carbon oxide, carbon dioxide, moisture d5, and sulfur compounds. These are synthetic zeolite 1~, activated carbon,
Hydrogen is adsorbed by an adsorbent such as silica gel, and only hydrogen is purified.

Depending on the need, the purity of hydrogen is 99.999 to 99.99.
A melon gas containing about 99% impurities, ie 1 to 10 ppm, is obtained.

However, in cases where the purity of hydrogen is not required to be this high, for example, when 99% or higher is sufficient, hydrogen separation efficiency will be higher if the purity is not increased more than necessary.
It is also a good idea because the amount of adsorbent may be small. In this case the main impurity is nitrogen. Pressure]jThe pressure of the variable adsorption method is appropriately selected depending on the place where the product hydrogen is used, but it is 10 to 30K.
(]/cnfg in most cases.The pressure drop inside the device is 0.5
The culm degree is ~1 to 9/cmg.

The exhaust gas from the pressure swing adsorber is usually used as fuel for subsequent reforming. In the case of this invention, since the catalyst is strong against sulfur and there is no need to desulfurize the raw material hydrocarbon, this 1/1 gas may contain sulfur and needs to be desulfurized. The amount of exhaust gas is large, and it is suitable as a fuel for secondary reforming.

Next, an example according to the present invention will be shown.

(a) Raw material Vacuum distillation residual oil composition C85, 59wt%! " 9.08II 8 4.10 〃 N 0.77 〃 0 0; 46II C/l" 9.43 Lower calorific value 9170kcaf/k (+ raw material oil
33.271kg/hour (1)) Secondary reforming Oxygen enriched air addition amount 12.134
ka/hour (02 depth 90%) (c) Reformed gas composition CO2 20.2 mol% Co 16.7 N2 57. 1 1lCI-Lt
4. 2"N21.1'Nt(drV) 126.91.1kCI/hour Moisture 135,733 II(d)-Carbon oxide conversion outlet Co2 30.9-Ele% C01,111 1-1262,81I CHI 3. 6 〃 N2 1.1” Total (dry) 146,549kg/hour Moisture
113.169 〃 (e) Tsujitsuno fluctuating adsorption device separation gas Hz 99.0 mol% N2 1.0” Co <10+) pm min [ffi 78.115 kq/hour (f) Pressure fluctuation adsorption device exhaust gas Co2 66,' 1 mol% Co 2.3 11112
21.51ICH47,8 N2 0.9Il meter
68,434kg/hour

[Brief explanation of the drawing]

Figure 1 Hydrogen production plan according to the present invention 1 ~ Block diagram 1 - Primary reforming process 2 Secondary reforming process 3 - Carbon oxide conversion reaction process 4 Pressure fluctuation adsorption process 5 Air separation device 6 Exhaust gas desulfurization process Applicant Heavy Oil Countermeasure Technology Research Association

Claims (1)

[Scope of Claims] (1) In the process of subjecting heavy hydrocarbons to steam reforming, passing through an oxidized carbon water conversion reaction stage, a residue purification step, and removing an aqueous system, (a) Small 1. The i4i hydrocarbons are subjected to the primary steam reforming reaction by external heating. (b) The reformed residue is then introduced into an adiabatic furnace, and oxygen or oxygen enriched as required (as required). or by adding air to the secondary steam reforming reaction or partial oxidation reaction. (d) 4SI gas is introduced across a pressure fluctuation adsorption method, and residues other than hydrogen are separated to obtain hydrogen.