JPH04159393A - Manufacture of city gas of high calorific value - Google Patents

Abstract

PURPOSE:To easily obtain a city gas of high calorific value in a short time with simple equipment by hydrogenating sulfur compounds in feedstock hydrocarbon, removing them by adsorption, reforming the desulfurized gas into a methane-rich gas, and mixing it with liquefied petroleum gas. CONSTITUTION:Feedstock hydrocarbon 11 (e.g. liquefied petroleum gas) is pumped by a pump 12, mixed with hydrogen 26, vaporized by a preheater 13 and a superheater 14, and introduced into a hydrodesulfurization tower 15, where it is hydrogenated in the presence of a hydrogenation catalyst and then sulfur compounds in the gas are removed by adsorption. The obtained desulfurized gas is mixed with process steam 16, and after raising the temperature thereof by a heating furnace 17, the mixture is introduced into a reforming tower 18, where it is reformed into a methane-rich gas in the presence of a steam-reforming catalyst. After heat recovery therefrom by a steam superheater 19, a preheater 20, a vaporizer 21, etc., the obtained methane-rich gas is cooled by a cooler 22. After removing moisture therefrom by a moisture separator 23, etc., it is mixed with liquefied petroleum gas 28 by a mixer 27 to give a city gas 29 having a calorific value as high as 11,000-14,000kcal/m<3>N and a combustibility rating of 12A or 13A.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention has a calorific value of 11,000 to 14,000 kc.
The present invention relates to a method for producing high-calorie city gas with a 1/m''N and flammability of 12A or 13A.

[Prior Art] This type of city gas has conventionally been produced by alternative natural gas production methods. In this production method, for example, as described in City Gas Industry Overview I (Practical Line) published by the Japan Gas Association, feedstock hydrocarbons such as naphtha are preheated and sulfur compounds in the feedstock hydrocarbons are converted to hydrogen. The hydrocarbons are removed by desulfurization, water vapor is added to the desulfurization gas, and the feedstock hydrocarbons are converted into methane-rich gas containing carbon monoxide, hydrogen, carbon dioxide, and water vapor, and the carbon monoxide and hydrogen of this hydrogenolyzed gas are After converting into methane and water vapor, carbon dioxide gas is removed from the obtained methane-rich gas, which is then cooled to obtain product city gas.

[Problems to be Solved by the Invention] However, such an alternative natural gas production method requires about 40 devices, the volume of the entire facility is large, and it takes a considerable amount of time to start up. Since it requires 6 hours, intermittent operation cannot be performed depending on the load.

The purpose of the present invention is to generate a calorific value of 11,000 to 14゜000k.
The object of the present invention is to provide a method for producing high-calorie city gas, which can obtain high-calorie city gas having a combustibility of 12A or 13A, and can be operated intermittently.

[Means for Solving the Problems] The production method of the present invention produces a calorific value of 11,000 to 14,000 k a 1 from raw material hydrocarbon by steam reforming.
It produces high-calorie city gas with a flammability of 12A or 13A and a hydrogenation process in which sulfur compounds in feedstock hydrocarbons are hydrogenated in the presence of a hydrogenation catalyst. A desulfurization process adsorbs and removes sulfur compounds in the gas, a reforming process in which the desulfurization gas obtained in the desulfurization process is reformed into methane-rich gas in the presence of a steam reforming catalyst, and the methane obtained in the reforming process is It consists of a calorific value adjustment step of mixing rich gas with liquefied petroleum gas to provide the above calorific value and combustibility.

[Action Co. Feedstock hydrocarbons include liquefied petroleum gas and naphtha.

The hydrogenation process is carried out at a temperature of 250-42°C in the presence of a cobalt-molybdenum catalyst or a nickel-molybdenum catalyst.
0°C 1 pressure is 5 to 9.5 kg/cm'G, the ratio of hydrogen to raw material hydrocarbon is 0.05 to 0.22 mol 1 mol, and the supply rate is 1 at liquid cylinder velocity (LH8V). ~10
Preferably, it is not h-1. Hydrogen mixed with the feedstock hydrocarbon is supplied from an independent hydrogen source or by recycling a portion of the methane-rich gas.

The desulfurization step is performed in the presence of a catalyst such as zinc oxide, iron oxide, or copper oxide, or an adsorbent such as activated carbon or molecular sieve. The reaction temperature is 200 to 4 in the case of zinc oxide catalyst.
00℃15-4 for iron oxide catalyst and copper oxide catalyst
00°C, 15-400'C for adsorbents such as activated carbon and molecular sieves, and pressures of 5-9°C, respectively.
It is preferable to do it at 5 kg/crn''G. The filling amount is 1,000 to 20,0 OOh-' in terms of void velocity (SV), depending on the adsorption performance.

In the reforming process, steam is added to the raw material gas that has left the desulfurization process at a ratio of the number of moles of steam to the number of carbons in the raw material hydrocarbon of 1.0 to 2.
．． It is preferable to carry out the reaction by mixing at 0° C. and reacting at a temperature of 280 to 520° C. in the presence of a nickel-based or noble metal-based steam reforming catalyst. The desulfurization gas thereby becomes a methane-rich gas.The pressure is 5-9.
．． 5kg/Cm”, the supply rate is 5,000 to 15,000 as the raw material gas loading speed at maximum load.
0 kg/m'h is preferred. This process can normally be carried out using only one tower, but two or three towers can be used if necessary.

The reaction is represented by the following formulas (1) to (3). In these formulas, formula (1) is a decomposition reaction, formula (2) is a methanation reaction, and formula (3) is a shift reaction.

CmHn0mH, 04mC0+ (m+n/2)H2・
...(1) CO+3 Hm→CH4+H Snow O...(2) CO+H
*o4+c O++ +H* -(3)
In equations (4) and (5), KPm is a methanation reaction equilibrium constant, and KPs is a shift reaction equilibrium constant.

The obtained methane-rich gas is almost in an equilibrium state according to formulas (4) and (5), and the standard composition (dry mol%) is H2: 10.5-14.0 CO: 0.5-1.0 CO2: 17.0-19.0 CH4: 68.0-70.0. This methane-rich gas has a temperature of, for example, 42
Since the temperature is 0 to 480°C, it can be used for superheating raw material hydrocarbons, generating steam added after the hydrogenation process, and vaporizing liquefied petroleum gas used for adjusting the amount of heat. The methane-rich gas from which the heat has been recovered is further cooled to a temperature of 50° C. or lower by a cooler, if necessary. Note that the above-mentioned recycled gas can be obtained by recycling a portion of the gas from which heat recovery has been completed.

In the heat adjustment step, for example, liquefied petroleum gas containing 25 mol% or more of propane is mixed with the gas after heat recovery,
This is done by adjusting city gas to have a predetermined combustibility. When the raw material hydrocarbon is liquefied petroleum gas, a part of the raw material liquefied petroleum gas used for calorific value adjustment may be separated and guided to the calorific value adjustment step.

The city gas production method of the present invention can include a CO conversion step during heat recovery in order to further reduce the carbon monoxide concentration contained in the gas produced in this way. This step is performed, for example, in the presence of a chromium oxide catalyst or a copper oxide catalyst, after cooling the methane-rich gas from the reforming step to a temperature of 170 to 850° C. required for CO conversion. The reaction temperature for each catalyst is
In the case of a chromium oxide catalyst, the temperature is 340 to 510°C, and in the case of a copper oxide catalyst, it is 170 to 290°C. The pressure is 5~
9.5 kg/cm"G.

In addition, the supply rate is 200 to 4 as a cylinder velocity (SV) in the case of a chromium oxide catalyst at the maximum load, ooooh
-'', and in the case of a copper oxide catalyst, the cylinder velocity (SV) is 200 to 20,0OOh-''T'. This reaction is expressed by the formula (
As shown in 3), the carbon monoxide concentration in the methane-rich gas is reduced to 0.1 dry mole % or less. The reaction itself is slightly exothermic, resulting in a temperature rise of 2 to 4°C.

Note that the dehydration process and the odorization process necessary before supplying city gas are incorporated, for example, between the heat recovery process and the heat amount adjustment process.

According to the city gas production method of the present invention, the flammability is such that the Wotsube index W1 is 750 to 13,800 and the combustion rate CP is 36.
．． You can get city gas of 5 to 70.0.

The flammability of city gas indicates its suitability for gas consumption equipment, and is determined by the combination of the Wotsube index WI and the combustion rate CP, where WI = Hg / f
5 CP=K (1,0Hz+o, 6 (CO+CmHn)
10, 3 CH4/rs. In these formulas, Hg is the total gas calorific value (kca]/m"), s is the specific gravity relative to air, H,
, Co and CH4 are the contents (volume %) of hydrogen, carbon oxide and methane, respectively, CmHn is the content (volume %) of hydrocarbons excluding methane, and K is a constant determined by the oxygen concentration in the gas.

City gas nationwide is classified into 13 gas groups based on combustibility. 12A and 13A are one of these 13 types of gas groups, and according to the Gas Business Law, the value of 12A is 11.75
0-12,850. Flammability is specified as 36.5 to 70.0, and that of 13A has a Uotsube index of 11.750 to 12.
850, and the flammability is defined as 36.5 to 70.0.

[Example 1] FIG. 1 shows an example of equipment based on the high calorie city gas production method of the present invention.

The raw material liquefied petroleum gas 11 is pumped by a raw material supply pump 12, mixed with hydrogen 26, vaporized and heated by a raw material preheater 13 and a raw material superheater 14, and then sent to a hydrodesulfurization tower 15.
The sulfur content in the raw liquefied petroleum gas is removed here. The desulfurized gas is mixed with process steam 16, heated in a raw material heating furnace 17, and then enters a reforming reaction tower 18, where it becomes a methane-rich gas containing hydrogen, carbon monoxide, and carbon dioxide. . The obtained methane-rich gas is
After the heat is recovered by the steam superheater 19, the boiler water heater 20, and the liquefied petroleum gas vaporizer 21 for adjusting the amount of heat, the cooler 2
2, water separator 23 and dehydrator 24
, moisture is removed therefrom, and liquefied petroleum gas 28 for calorific value adjustment is mixed in a calorific value adjustment mixer 27 to produce product city gas 29 .

The hydrogen 26 is supplied by compressing a part of the methane-rich gas leaving the water separator 23 using a recycling compressor 25 and returning it to the raw material liquefied petroleum supply line. The process steam 16 is supplied by pumping water 30 to the water pump 3.
1, heated by a boiler feed water subheater 20, vaporized by a boiler 32, and superheated by a steam superheater 19. In order to supply the liquefied petroleum gas 28 for adjusting the calorific value, before mixing the hydrogen 26, a part of the raw liquefied petroleum gas 11 is diverted, vaporized in the liquefied petroleum gas vaporizer 21 for adjusting the calorific value, and then supplied to the mixer 27 for adjusting the calorific value. It is done by sending.

Production example 1 The raw material hydrocarbon is liquefied petroleum gas, propane 9 mmol%,
Consists of 10 mol% butane and 10 ppm
Contains hydrogen sulfide and organic sulfur before and after.

The liquefied petroleum gas 11 is pressurized to a pressure of 9.5 kg/cm'G by a pump 12, and a part of the liquefied petroleum gas 11 is separated and mixed with a recycled gas 16. The flow rate ratio of recycled gas/liquefied petroleum gas is 0. It is made in 1 mole of 1 mole. Then, the raw material gas is transferred to the raw material preheater 13 and the raw material superheater 14.
The temperature is raised to 380° C., and the product is introduced into the hydrodesulfurization tower 15 at a pressure of 9.0 kg/cm”G.

The sulfur content contained in the raw material liquefied petroleum gas reacts with hydrogen in the recycled gas in the presence of a cobalt-molybdenum catalyst in the upper part of the hydrodesulfurization tower 15 and turns into hydrogen sulfide. This hydrogen sulfide is removed by a zinc oxide catalyst in the lower part of the hydrodesulfurization tower 15, and leaves the hydrodesulfurization tower 15 at a temperature of 380°C. The sulfur content in the raw material gas becomes 0.2 ppm or less.

The raw material gas leaving the hydrodesulfurization tower 15 is mixed with steam 16 . The mixing is performed at a ratio of the number of moles of steam to the number of carbons in the liquefied petroleum gas of 1.0 mol/atom. The temperature of the raw material gas mixed with water vapor drops to around 295°C, so it is heated again to 880°C in the heating furnace 17.
pressure cuff.

It is sent to the reforming reaction tower 18 at 6 kg/cm'G.

The reforming reaction tower 18 is filled with a nickel-based steam reforming catalyst, and the raw material gas that has entered the reaction tower becomes methane-rich gas through a reforming reaction. Composition of methane-rich gas (d
ry mole %) is approximately H,: 11.9 CO: 0.7 cot: 17.4 CH4 near 0.0. Since the reaction here is an exothermic reaction, the temperature of the methane-rich gas leaving the reforming reaction tower 18 is approximately 451°C. After this, the methane-rich gas is transferred to the raw material superheater 14, the steam superheater 19, the boiler feed water heater 20. Raw material preheater 13
, a liquefied petroleum gas vaporizer 21 for adjusting calorific value, heat is recovered, and after being cooled to a temperature of 45° C. or less in a cooler 22, condensed water is separated in a water separator 23 and sent to a dehydrator 24. The dehydrator 24 uses a deep cooling method, and most of the moisture in the methane-rich gas is removed here.

The produced gas that has exited the dehydration bag [24] is led to a mixer 27 for adjusting the calorific value, and is mixed with liquefied petroleum gas for adjusting the calorific value. As described above, the calorific value adjusting gas is a liquefied petroleum gas containing 90 mol% of propane and 10 mol% of butane, which is separated from the raw material line. The methane-rich gas and the liquefied petroleum gas for adjusting the calorific value are mixed in a ratio of about 64/about 36 mol%. The properties of the obtained city gas 29 are as follows.

Composition (mol%) H, Near, 6 CO:0.4 Co: 11.2 CH, :44.9 C, H, :82. 3 C.H. =3.6 Calorific value: 13,500kca 1/m”N.

Specific gravity 1.006 Wotsube index (WI) 13,459 Burning rate (CP
) 42.8 Production Example 2 The raw material hydrocarbon is liquefied petroleum gas, 25 mol% of propane,
Consisting of 75 mol% butane and 5p
Contains hydrogen sulfide and organic sulfur at around pm.

The liquefied petroleum gas 11 is pressurized to a pressure of 9.5 kg/cm''G by the pump 12, and a part of the liquefied petroleum gas 11 is diverted to the heat adjustment process, and then mixed with the recycled gas 16.The flow rate ratio is determined as follows: The raw material gas is heated to 300°C by the raw material preheater 13 and the raw material superheater 14.
It is led to the hydrodesulfurization tower 15 at a pressure of 9.0 kg/cm''G.

The sulfur content contained in the raw material liquefied petroleum gas reacts with hydrogen in the recycled gas in the presence of a cobalt-molybdenum catalyst in the upper part of the hydrodesulfurization tower 15 and turns into hydrogen sulfide. This hydrogen sulfide is removed by a zinc oxide catalyst in the lower part of the hydrodesulfurization tower 15 and leaves the hydrodesulfurization tower 15 at a temperature of aoo'c. Sulfur content in raw gas is 0.2pp
m or less.

The raw material gas leaving the hydrodesulfurization tower 15 is mixed with steam 16 . The mixing is performed at a ratio of the number of moles of steam to the number of carbons in the liquefied petroleum gas of 1.5 mol/atom. The temperature of the raw material gas mixed with water vapor drops to around 235°C, so it is reheated to 280'C in the heating furnace 17 and then heated to the reforming reaction tower 18 with a pressure cuff of 6 kg/cm"G.
sent to.

The reforming reaction tower 18 is filled with a nickel-based steam reforming catalyst, and the raw material gas that has entered the reaction tower becomes methane-rich gas through a reforming reaction. Composition of methane-rich gas (d
r 7 mol%) is approximately H3 co7. 6 CO: 0.1 Cow: 18. 8 CH, +73. It is 5. Since the reaction here is exothermic, the temperature of the methane-rich gas leaving the reforming reaction tower 18 is approximately 371'C.
become. After this, the methane-rich gas is transferred to the raw material superheater 14
, steam superheater 19, boiler feed water heater 20. The heat is recovered through the raw material preheater 13 and the liquefied petroleum gas vaporizer 21 for adjusting the amount of heat, and after being cooled to a temperature of 45° C. or less in the cooler 22, the condensed water is separated in the water separator 23,
It is sent to the dehydrator 24. The dehydrator 24 uses a deep cooling method, and most of the moisture in the methane-rich gas is removed here.

The produced gas leaving the dehydrator 24 is led to a mixer 27 for adjusting the calorific value, and is mixed with liquefied petroleum gas for adjusting the calorific value. The calorific value adjusting gas is a liquefied petroleum gas containing 25 mol% of propane and 75 mol% of butane, which is separated from the above-mentioned raw material line. The mixing is carried out at a ratio of about 81/about 19 mol % of methane rich gas and liquefied petroleum gas for adjusting calorific value. The properties of the obtained city gas 29 are as follows.

Composition (mol%) H: 6.2 CO:0. I Co: 15.3 CH, :59,8 CsHs: 4. 6 C.H. :14,0 Calorific value 11,500kca 17m”N.

Specific gravity 0.935 Wotsube index (WI) 11,893 Burning rate (CP
) 36.6 In the high-calorie city gas production method of the present invention, as described above, in order to further reduce the carbon monoxide concentration contained in the obtained city gas, a CO conversion step can be included.

FIG. 2 shows an example of equipment for this purpose, and except for the CO conversion tower 33, the same reference numerals as in FIG. 1 indicate the same equipment.

Production example 3 The raw material hydrocarbon is liquefied petroleum gas, 90 mol% propane,
Consisting of 10 mol% butane and 10 ppp
Contains hydrogen sulfide and organic sulfur of around m.

The liquefied petroleum gas 11 is pressurized to a pressure of 9.5 kg/cm'2G by the pump 12, and a part of the gas is diverted to the calorific value adjustment step, and then recycled gas 16 is mixed therein. The flow rate ratio is 0.08 mol/mol of recycled gas/liquefied petroleum gas. Then, the raw material gas is heated to a temperature of 380°C by the raw material preheater 13 and the raw material superheater 14, and is led to the hydrodesulfurization tower 15 at a pressure of 9.0 kg/cm2G.

The sulfur content contained in the raw material liquefied petroleum gas reacts with hydrogen in the recycled gas in the presence of a cobalt-molybdenum catalyst in the upper part of the hydrodesulfurization tower 15 and turns into hydrogen sulfide. This hydrogen sulfide is removed by a zinc oxide catalyst in the lower part of the hydrodesulfurization tower 15 and leaves the hydrodesulfurization tower 15 at a temperature of 380°C. The sulfur content in the raw material gas becomes 0.2 ppm or less.

The raw material gas leaving the hydrodesulfurization tower 15 is mixed with steam 16 . The mixing is performed at a ratio of the number of moles of water vapor to the number of carbons in the liquefied petroleum gas of 1.2 mol/atom. When water vapor is mixed, the temperature of the raw material gas drops to around 281°C, so it is reheated to 880°C in the heating furnace 17.
It is sent to the reforming reaction tower 18 with a pressure cuff of 6 kg/cm2G.

The reforming reaction tower 18 is filled with a nickel-based steam reforming catalyst, and the raw material gas that has entered the reaction tower becomes methane-rich gas through a reforming reaction. Composition of methane-rich gas (d
ry mole %) is approximately H,: 13.3 CO: 0.5 CO,: 17.6 CH, +68.6. Since this reaction is an exothermic reaction, the methane-rich gas released from the reforming reaction is heat-recovered by the raw material superheater 14 and the steam superheater 9, and then the temperature is 250°C and the pressure is 6.
．． Enter CO transformation tower 23 with 3kg/cm” G.

The CO conversion tower 23 is filled with a copper oxide catalyst. Carbon monoxide in the methane-rich gas is reduced to 0.04 mol% or less by the shift reaction shown in equation (3). C
Since the temperature of the transformed gas leaving the O transformation tower 23 is 253°C, the boiler feed water heater 20. The heat is recovered through the raw material preheater 13 and the liquefied petroleum gas vaporizer 21 for adjusting the amount of heat, then cooled to a temperature of 45° C. or lower in the cooler 22, and then the condensed water is separated in the water separator 23 and dehydrated. is sent to device 24.

Dehydration gear! The production gas that has reached ’24 is sent to mixer 27 for adjusting the heat amount.
and mixed with liquefied petroleum gas for calorific value adjustment. As described above, the calorific value adjusting gas is a liquefied petroleum gas containing 90 mol% of propane and 10 mol% of butane, which is separated from the raw material line. The methane-rich gas and the liquefied petroleum gas for adjusting the calorific value are mixed in a ratio of about 69/about 31 mol%. The properties of the obtained city gas 29 are as follows.

Composition (mol%) Hz: 9.5 CO:0.0 CO,: 12.5 CH, :47.2 C Hl, :27,7 C.H. 28.1 Calorific value 12,500kca 17m”N.

Specific gravity 0. 955 Wotsube Index (WI) 12,792 Burning Rate (CP
) 43.1 [Effects of the Invention] As explained above, according to the production method of the present invention, high-calorie city gas having a calorific value of 11,000 to 14,0000 kcal/m"N and a flammability of 12A or 113A can be produced. , the number of devices has increased from about 40 in conventional manufacturing facilities to about 20.
It can be obtained with less manufacturing equipment, the volume of the entire manufacturing equipment is smaller, so the start-up time is shorter than the conventional 5~
The time is shortened from 6 hours to about 1 hour, and intermittent operation can be easily performed.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the configuration of production equipment based on the high calorie city gas production method of the present invention, and FIG. 2 is an explanatory diagram showing the configuration of the production equipment based on another high calorie city gas production method of the present invention. be. 11... Raw material hydrocarbon, 15... Hydrodesulfurization tower, 16
...Steam, 18... Reforming reaction tower, 26... Hydrogen, 27... Calorific value adjustment mixer, 28... Gas for calorific value adjustment, 29... Product city gas, 33... CO Metamorphosis tower.

Claims (1)

[Claims] 1. Calorific value 11,
000-14,000kcal/m^3N, flammability 12
In the method of producing A or 13A high-calorie city gas, a hydrogenation step of hydrogenating sulfur compounds in a raw material hydrocarbon in the presence of a hydrogenation catalyst, and a sulfur compound in the gas obtained in the hydrogenation step. a desulfurization process in which the desulfurization gas obtained in the desulfurization process is adsorbed and removed, a reforming process in which the desulfurization gas obtained in the desulfurization process is reformed into methane-rich gas in the presence of a steam reforming catalyst, and liquefied petroleum gas is added to the methane-rich gas obtained in the reformation process. A method for producing high-calorie city gas, comprising a step of adjusting the calorific value by mixing to provide the calorific value and combustibility. 2. Calorific value 11,
000-14,000kcal/m^3N, flammability 12
A method for producing A or 13A high-calorie city gas, which includes a hydrogenation step, a desulfurization step, a reforming step, and a calorific value adjustment step performed at a pressure of less than 10 kg/cm^2G, and in the hydrogenation step, raw material carbonization Hydrogen is mixed with hydrogen to hydrogenate sulfur compounds in the raw material hydrocarbon in the presence of a cobalt-molybdenum-based or nickel-molybdenum-based hydrogenation catalyst, and in the desulfurization process, the sulfur compounds in the gas obtained in the hydrogenation process are is adsorbed and removed using a catalyst such as zinc oxide, iron oxide, or copper oxide, or an adsorbent such as activated carbon or molecular sieve.
In the reforming process, the desulfurized gas is reformed into methane-rich gas in the presence of a nickel-based or precious metal-based steam reforming catalyst, and in the heat adjustment process, liquefied petroleum gas is mixed with the methane-rich gas obtained in the reforming process. A method for producing high-calorie city gas, characterized in that the gas has the above-mentioned calorific value and the above-mentioned combustibility. 3. Calorific value 11,
000-14,000kcal/m^3N, flammability 12
A method for producing A or 13A high-calorie city gas, which includes a hydrogenation step, a desulfurization step, a reforming step, and a calorific value adjustment step performed at a pressure of less than 10 kg/cm^2G, and in the hydrogenation step, raw material carbonization Hydrogen is mixed with hydrogen, and in the presence of a cobalt-molybdenum-based or nickel-molybdenum-based hydrogenation catalyst, sulfur compounds in the raw material hydrocarbon are hydrogenated at a temperature of 250 to 420°C. The sulfur compounds in the collected gas are converted to zinc oxide, iron oxide,
It is adsorbed and removed using a catalyst such as copper oxide or an adsorbent such as activated carbon or molecular sieve, and in the reforming process, water vapor is added to the desulfurized gas at a ratio of 1.0 to 2. 0 and mixed at a temperature of 280 to 520 in the presence of a nickel-based or noble metal-based steam reforming catalyst.
The methane-rich gas is reformed by a reaction at ℃, and in the heat adjustment step, the methane-rich gas obtained in the reforming step is mixed with liquefied petroleum gas to provide the above-mentioned calorific value and combustibility. gas production method for high-calorie cities. 4. Calorific value 11,
000-14,000kcal/m^3N, flammability 12
A method for producing A or 13A high-calorie city gas, which comprises a hydrogenation step, a desulfurization step, a reforming step, and a calorific value adjustment step performed at a pressure of less than 10 kg/cm^2G, and the raw material hydrocarbon is liquefied petroleum gas. In the hydrogenation process, hydrogen is mixed with this liquefied petroleum gas, and the sulfur compounds in the liquefied petroleum gas are heated at a temperature of 250 to 42°C in the presence of a cobalt-molybdenum-based or nickel-molybdenum-based catalyst.
Hydrogenation is carried out at 0°C, and in the desulfurization process, sulfur compounds in the gas obtained in the hydrogenation process are removed using adsorbents such as zinc oxide, iron oxide, copper oxide catalysts, activated carbon, and molecular sieves.
In the reforming process, water vapor is added to the desulfurized gas at a ratio of 1.0 to 1.0 to 1.0 to 1.
5 and reacted in the presence of a nickel-based or noble metal-based steam reforming catalyst at a temperature of 280 to 460°C to reform into methane-rich gas, and in the calorific value adjustment step, the methane-rich gas obtained in the reforming step A method for producing high-calorie city gas, which comprises mixing liquefied petroleum gas with gas to provide the above-mentioned calorific value and combustibility. 5. The manufacturing method according to any one of claims 1 to 4, wherein in the hydrogenation step, a part of the methane-rich gas containing hydrogen generated in the reforming step is recycled to perform the mixing.