RU152752U1 - STEAM ORGANIC FUEL CONVERTER ON THE BASIS OF NON-STABILITY CONSTRUCTION MATERIALS WITH REDUCED ENERGY LOSSES WITH EXHAUST GASES - Google Patents

Abstract

An organic fuel steam converter comprising a steam conversion reactor and a combustion device, characterized in that it is additionally equipped with a jet apparatus with pipelines supplying part of the exhaust gases to the combustion device and providing for their recirculation in the steam converter using residual synthesis gas energy, and the reactor Steam conversion steam converter is made of non-heat-resistant structural materials.

Description

The utility model relates to the field of generation of pure hydrogen from fossil fuels and can be used in the chemical industry and in the energy sector, in particular, in transport and stationary power plants with electrochemical generators (ECG).

Hydrogen production (see. Hydrogen. Properties, production, storage, transportation, use: Reference edition: Edited by D.Yu. Hamburg, NF Dubovkin - M .: Chemistry, 1989) is possible in the following ways:

- thermochemical decomposition of water;

- electrolysis of water;

- catalytic conversion of hydrocarbons.

The main modern industrial method for generating hydrogen is the process of steam conversion of hydrocarbons, which consists in the decomposition of the feedstock in the presence of catalysts and at high temperature into a mixture of hydrogen, methane, carbon monoxide and carbon dioxide, followed by the release of pure hydrogen from a hydrogen-containing gas (see V. Arutyunov, Orlov OV Oxidative transformations of methane. - M .: Nauka, 1998). As the feedstock, both gaseous and liquid hydrocarbons can be used.

A known method of producing highly pure hydrogen (RF patent No. 2085476, C01B 3/32, 3/56, publ. 07.27.97), including sequential desulfurization of natural gas (GHG), mixing purified GHG with water vapor, steam conversion of the obtained gas-vapor mixture in a catalytic reactor to produce a mixture containing hydrogen and carbon monoxide, steam conversion of carbon monoxide in a converter, compressing the gas mixture, freezing carbon dioxide and water from it, and diffusing hydrogen through a palladium membrane with the release of very pure hydrogen.

The disadvantages of this method are as follows:

- provides for compressor compression of the gas mixture in the final stages of the process;

- hydrogen-containing gas after the separation of water and carbon dioxide by freezing has a low temperature. Diffusive evolution of hydrogen on a palladium membrane should occur at a temperature of from 773 to 900 K, which requires the supply of heat to heat the incoming gas and increases the cost of hydrogen production;

- the method does not provide for the utilization of heat of the exhaust flue gases, which can be used to heat the feed mixture fed to the steam reforming catalytic reactor, and to heat the air supplied to the combustion device, which leads to an increase in the specific fuel consumption per unit of produced products.

A known method of producing hydrogen from hydrocarbon gas (RF patent No. 2088517, C01B 3/32, 3/56, publ. 08.27.97).

In this method, steam conversion of a hydrocarbon gas is performed to produce a gas containing hydrogen and carbon monoxide. The resulting gas is fed to the conversion of carbon monoxide, then the converted gas is cooled to separate water condensate and carbon dioxide is released from the converted gas. Purification of the obtained hydrogen-containing gas from impurities is carried out by the method of short-cycle adsorption to produce hydrogen. The adsorbent is regenerated by purging part of the hydrogen produced to produce regeneration gases that are returned to the carbon monoxide conversion stage. The conversion stages are carried out at atmospheric pressure, and the adsorption stages are carried out at a pressure of from 1.5 to 3.0 MPa, for which the gas in front of the short-cycle adsorption apparatus is compressed using a compressor. Before applying to the steam conversion, condensation is carried out by hydrocarbon gas. This method has disadvantages:

- since the conversion stages of the process take place at atmospheric pressure, the metal consumption of the process equipment increases;

- at the final stages of the process, the gas mixture is compressed by a compressor from 1.5 to 3.0 MPa, which leads to an increase in the cost of equipment and maintenance;

- the allocation of carbon dioxide from the gas mixture is provided in a separate adsorber, which leads to an increase in the cost of installation;

- this method does not provide for the utilization of heat from the exhaust flue gases.

Also known is a power plant on fuel cells with a solid polymer electrolyte using hydrocarbon fuel (RF patent No. 2353023, H01M 8/06, publ. 04/20/2009).

The power plant contains a power generation subsystem, a hydrocarbon fuel processing subsystem with a desulfurizer, a fuel humidifier, a steam reforming reactor, a carbon monoxide converter, an oxidizer subsystem with a compressor, a water regeneration subsystem, a temperature control subsystem with a pump for circulating liquid, a heat exchanger for dissipating excess heat and a pre-cooler fuel The temperature control subsystem additionally introduces a starting thermostat heater Liquids with a burner.

The method of producing hydrogen, implemented in the power plant under consideration, has a major drawback - the presence of a starting heater. The introduction of an additional starting heater increases the fire hazard of the installation, which is unacceptable for installations operating in confined spaces (compartments).

The most technically closest adopted as a prototype to the proposed utility model is the design of the installation for producing hydrogen from hydrocarbons according to the patent of the Russian Federation No. 2394754, C01B 3/34, C01B 3/12, publ. 07/20/2010. The installation comprises a hydrocarbon feed to the desulfurization unit, after which the hydrocarbon gas purified from sulfur compounds is divided into two streams. One gas stream is mixed with water vapor and subjected to steam reforming in a steam reforming catalytic reactor at a temperature of 800-1050 ° C. The obtained converted gas is fed as a heating medium to a steam recovery boiler, the gas cooled therein is sent to a catalytic reactor for steam conversion of carbon monoxide at a temperature of 190-220 ° C, then the resulting hydrogen-containing gas is additionally cooled to a temperature of 20-40 ° C by an external refrigerant and is separated from moisture in a gas cooler-dryer, after which it is fed to a hydrogen-containing gas separation unit in which hydrogen is released by short-cycle adsorption. Purge gas is diverted from the separation unit and mixed with a second stream of sulfur-free hydrocarbon gas, the resulting mixture is fed as fuel gas to the burner of a catalytic steam reforming hydrocarbon reactor, before being fed to the burner, this mixture and the air required for combustion are heated in a heat recovery unit, after whereby the flue gases to separate the moisture are additionally cooled by an external coolant in the flue gas cooler-dryer and are taken out of the installation to the atmosphere.

The disadvantages of this prototype are:

- Carrying out the conversion of hydrocarbons at high temperature, leading to the need to use expensive structural materials;

- the presence of significant heat losses, compensated by supplying not only purge gas for combustion, but also an additional amount of hydrocarbon fuel.

The objective of the proposed utility model is to create the design of a steam converter of organic fuel, which allows to increase the energy efficiency of its application and reduce the cost of its production.

The technical result of the utility model is the use of energy of exhaust (flue) gases, while eliminating the need to use expensive heat-resistant steels for its manufacture, and use non-heat-resistant structural materials in the manufacture of the proposed utility model.

The technical result is achieved by the fact that, according to the proposed utility model, a jet apparatus (injector) is included in the design of the steam converter of organic fuel, which ensures the recirculation of the flue gases in the steam converter.

The structural diagram of the steam converter and the circuit for including the steam converter in the hydrogen production cycle are shown in the illustrations of FIG. 1 and FIG. 2 respectively.

The following elements are indicated in the illustrations:

1 - Air supply pipe;

2 - Water supply pipeline;

3 - Pipeline for the removal of hydrogen;

4 - Inkjet apparatus (injector);

5 - furnace device;

6 - Steam conversion reactor;

7 - Steam Converter;

8 - Mixer;

9 - Fuel supply pipe;

10 - heat exchanger;

11 - heat exchanger;

12 - Flue gas discharge pipe;

13 - Pipeline return part of the flue gases to the combustion device;

14 - Residual synthesis gas pipeline;

15 - The pipeline for supplying the fuel mixture to conversion.

The design of the utility model and its operation is illustrated by the following specific example of its implementation and the accompanying drawing of FIG. 1, which shows a steam fossil fuel converter with an integrated inkjet apparatus.

The fuel mixture prepared in the mixer enters the converter via pipeline 15. To receive it, the mixer 8 is supplied with the fuel supply pipe 9 and the water supply pipe 2 after the heat exchanger 10, where vaporization takes place, respectively, the starting organic fuel and the generated steam are supplied. The process of converting the fuel mixture is carried out when it is heated. Heating is carried out using a furnace device, which is part of the converter, to which the residual synthesis gas is supplied via line 14, and air is supplied through line 1 to carry out its combustion. Part of the flue gases is circulated through the steam reforming reactor 6 using a jet apparatus (injector) 4 through a pipe 13 with a gas supply to the combustion device 5. The working medium (residual synthesis gas) enters the jet apparatus through a pipeline 14. The steam reforming formed in the reactor 6, hydrogen is discharged to the consumer through pipeline 3, and the flue gases are discharged into the pipeline 12.

The circuit for incorporating the converter into the hydrogen production cycle is shown in the illustration of FIG. 2.

The utility model uses the process of steam conversion of hydrocarbons with decomposition of the feedstock into a mixture of hydrogen, methane, carbon monoxide and carbon dioxide (synthesis gas), followed by membrane separation of pure hydrogen from a hydrogen-containing gas. The greater the conversion depth, the less carbon monoxide and methane in the hydrogen-containing gas. The complete conversion of the feedstock is described by the reaction equation:

C _n H _m + 2n · H ₂ O = n · CO ₂ + (2n + m / 2) · H ₂ + Q,

Where:

C _n H _m is the averaged formula for the initial mixture of hydrocarbons;

Q is the thermal effect of the reaction, numerically equal to the amount of heat that must be summed up for the conversion of one mole of the feedstock at a constant temperature.

Hydrocarbon conversion is an endothermic reaction with heat input. The actual composition of the resulting synthesis gas and the actual value of the thermal effect of the reaction depend both on the composition of the feedstock and on the physical conditions of the conversion. The conversion is carried out at high temperature, which increases the speed and depth of the reaction, and at elevated pressure, which increases the flow of hydrogen through a unit surface of membranes made of expensive metals and alloys, allowing them to reduce their total surface and significantly reduce the cost of the design of devices for separating hydrogen. The heat required for the conversion, as well as the heat required for the generation of water vapor from the water, is provided by burning the residual synthesis gas after most of the hydrogen has been released from it. The residual synthesis gas is burned in the combustion device 5 with the formation of hot flue gases, which serve as a coolant for heat transfer in the steam reforming reactor (RPK) of the converter with heat exchangers 10 and 11. The temperature of the flue gases at the inlet of the RPK should not be higher than 750 ° C, which, considering that the temperature of the surfaces in contact with the flue gases is approximately 100 ° C lower, eliminates the use of expensive heat-resistant structural materials. On the other hand, the temperature of the exhaust gases at the outlet of the RPK should not be too low to ensure high RPK hydrogen output. With a relatively small difference between the inlet and outlet temperatures of the exhaust gases, the necessary heat flow is ensured due to the large consumption of exhaust gases, which, without taking special measures, leads to large heat losses during removal of the exhaust exhaust gas. The design of the utility model allows to ensure the flow of exhaust gases through the RPK, many times exceeding the amount of exhaust gases, due to the organization of recirculation of a significant part of it. In the proposed utility model, recirculation is carried out using an injector (inkjet apparatus). The injected medium of the jet apparatus is part of the gases leaving the RPK, and the working medium is the residual synthesis gas. In this case, the circumstance is used that the pressure of the residual gas is high and slightly different from the pressure in the conversion zone, and the pressure in the exhaust gas path is close to atmospheric. Thus, recirculation is carried out without additional energy consumption and the device is highly reliable, because the inkjet apparatus does not contain moving parts. The heat energy of the outgoing part of the gases is utilized in a heat exchanger 10 generating steam supplied to the mixer 8 for mixing with the original fuel, and then in the heat exchanger 11, which heats the air supplied to the furnace. As a result, energy losses with flue gases are minimal.

Lowering the temperature level makes it possible to use non-heat-resistant structural materials, including the widely used corrosion-resistant steels 12X18H10T, 12X18H9T, 08X18H10T according to GOST 5632-72, instead of steels with increased heat resistance of the grades ХН45Ю, ХН78Т and other similar ones. At the same time, a wide range of rolled products, proven technologies of machining and welding become available, and it turns out to be lower by more than an order of magnitude.

Claims (1)

An organic fuel steam converter comprising a steam conversion reactor and a combustion device, characterized in that it is additionally equipped with a jet apparatus with pipelines supplying part of the exhaust gases to the combustion device and providing for their recirculation in the steam converter using residual synthesis gas energy, and the reactor Steam conversion steam converter is made of non-heat-resistant structural materials.

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