JPS62957B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for purifying high-temperature gas containing sulfur and dust obtained by gasifying solid hydrocarbons or liquid hydrocarbons such as coal and coke. It is.

[Prior Art] A high-temperature desulfurization process for high-temperature gasification gas currently under development generally involves desulfurization at a temperature range of 750 to 1000°C using a desulfurization agent based on dolomite or limestone.

[Problem that the invention seeks to solve]

Using this dolomite, limestone, etc.
Desulfurization methods performed at temperatures around 750 to 1000℃ are extremely advantageous in terms of reaction rate and desulfurization rate, but on the other hand,
In this high temperature range, carbon is significantly deposited due to the thermal decomposition or polymerization reaction of liquid hydrocarbons produced as a by-product during gasification, and this carbon clogs the desulfurizing agent and reduces the activity of the desulfurizing agent. Furthermore, in this high temperature range, there is a problem that the desulfurizing agent becomes semi-molten and loses its activity, which is so-called sintering.

The present invention was developed in view of the above points, and after rapidly cooling high-temperature gas from a gasifier to 350 to 600°C to suppress carbon precipitation, this gas is desulfurized. By devising the structure of the exchange equipment and desulfurization equipment so that dust removal can be performed at the same time as desulfurization, and by combining equipment that incinerates the waste from these equipment, it is possible to effectively recover energy. The purpose of the present invention is to provide a high-temperature gas purification method.

[Means and actions for solving problems]

The high-temperature gas purification method of the present invention involves purifying high-temperature gas obtained by gasifying solid hydrocarbons containing sulfur or liquid hydrocarbons containing sulfur.
The high-temperature gas is guided to a fluidized bed type gas quenching heat exchanger and cooled to 350 to 600℃, and then introduced to a moving bed type desulfurization/dust collection device that uses a desulfurizing agent as a filter to desulfurize the gas and remove dust at the same time. The waste fluid material from the gas quench heat exchange equipment and the dust collected by the desulfurization/dust collection equipment are incinerated in a fluidized bed incinerator, and the recycled fluid material is returned to the gas quench heat exchange equipment for reuse. At the same time, it also removes dust from combustion exhaust gas and recovers energy.

When carrying out the method of the present invention, the cooling temperature is
If the cooling temperature is less than 350°C, the desulfurization effect will not be sufficiently exhibited, and if the cooling temperature exceeds 600°C, the desulfurization effect will not be sufficiently exhibited and sintering may occur, which is not preferable.

In the present invention, a fluidized bed type gas quenching heat exchange device is used as a quenching device for the generated gas, and a fluidized bed type incinerator is used as an incinerator. For this purpose, a part of the liquid carbonized substance and/or carbon generated during gasification is attached to or entrained in the fluid substance of the fluidized bed type gas quenching heat exchange device,
By incinerating in a fluidized bed type incinerator, we aim to reduce the dust collection load in the dust collection section.

In addition, the fluidized material heated in the fluidized bed type incinerator is returned to the fluidized bed type gas quenching heat exchanger for reuse, thereby improving heat recovery in the gas quenching heat exchanger.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. The drawing shows an example of a device for carrying out the method of the invention. The high-temperature gasified gas gasified in the gasifier 1 is introduced from the bottom into a fluidized bed type gas quenching heat exchanger 3 through a cyclone 2, where it is rapidly cooled to a desulfurization temperature of 350 to 600°C. The gas is introduced into a desulfurization/dust collection device 5 through a cyclone 4, where it is desulfurized and dust removed at the same time, and taken out from a clean gas outlet 6 as a clean gasified gas. The gas quenching heat exchange device 3 is filled with a fluidized medium 7 such as alumina balls, silica balls, coke, char, silica sand, ash, etc. in a fluidized manner, and a heat transfer tube 8 is provided within this fluidized bed. By adopting the fluidized bed type as the gas quenching heat exchange device in this way, it is possible to reduce the heat transfer area of the heat transfer tubes 8 built into the gas quenching heat exchange device, and
Even if the generated gasified gas contains heavy hydrocarbons such as tar, by appropriately selecting the gas flow rate in the fluidized bed and the tube wall temperature of the heat transfer tube,
Coking occurs on the fluid material without causing coking on the surface of the heat exchanger tubes, and as a result, there is no coking trouble in the heat exchanger tubes that tends to occur in conventional quenching heat exchangers, and therefore, it is possible to avoid the coking troubles that occur in conventional quenching heat exchangers. Decoking operation becomes unnecessary. The operating conditions of the gas quenching heat exchanger 3 depend on the type of raw material and gasification conditions, but the gas flow rate in the fluidized bed is
2 m/s or more, and the tube wall temperature of the heat exchanger tube is preferably 350°C or more or 200°C or less.

The desulfurization/dust collection device 5 uses 350 to 600 as a desulfurization agent.
Fe ₂ O ₃ , ZnO, CuO, CaO, which has desulfurization effect at ℃
It is a moving bed type dust collection device using particles (1 to 5 mm) of CaO+MgO and the like and this desulfurization agent 10 as a filter material, and is configured to be able to perform dust removal at the same time as desulfurization. This desulfurization/dust collection device 5
To explain this in more detail, the desulfurizing agent 10 is movably filled in a cylindrical layer between supports 11 such as louvers, wire mesh, perforated plates, etc., and the gasification gas introduced from the outside of the packed bed is removed at the same time as desulfurization. It is configured so that it is blown out and flows into the clean gas passage 12 in the central part as a clean gasified gas. Note that the desulfurization/dust collection device is not limited to the structure described above, and may have a structure in which one or more flat packed beds are provided.

The dust collected in the desulfurization/dust collector 5 is
It is extracted from the lower part of the desulfurization/dust collector together with the desulfurization agent and sent to the classifier 13. The desulfurizing agent and dust are separated by the classifier 13, and the desulfurizing agent is regenerated by the desulfurizing agent regenerating device 14, and then returned to the desulfurizing/dust collecting device 5 by a conveyor or other transfer device 15 for reuse. It is sent to a fluidized bed type incinerator, which will be described later, and burned. On the other hand, the waste fluid material with carbon attached from the gas quenching heat exchange device 3 is sent to the lower part of the fluidized bed type incinerator 17 through the waste fluid material conduit 16, and is sent through the dust conduit 18 to the desulfurization/dust collection device. It is processed in this incinerator 17 together with the dust collected in step 5. The fluid material in which the carbon adhering to the surface has been burned, that is, the regenerated fluid material, is returned to the gas quenching heat exchanger 3 through the regenerated fluid material conduit 20 and is reused.

The combustion exhaust gas discharged from the incinerator 17 passes through a cyclone 21 built into the incinerator 17 and is removed by a dry dust collector 22, and then a turbine 23 generates power to recover pressure energy and temperature energy. Then, the exhaust gas heat exchanger 24 exchanges heat with the boiler feed water to be supplied to the heat exchanger tubes 8 of the gas quenching heat exchanger 3 to preheat the boiler feed water and recover the energy, which is then released into the atmosphere. The power recovered by the turbine 23 can be used for power generation,
It is also possible to drive an air compressor 25 that supplies combustion air for incineration. 26 is an electric motor for starting the incinerator, 27 is a steam drum, and 28 is an ash removal pipe.

Note that when the high-temperature gas purification process is operated near normal pressure, the incinerator 17 is not provided with the turbine 23.
After removing dust from the combustion exhaust gas, the exhaust gas is directly introduced into the exhaust gas heat exchanger 24.

〔Effect of the invention〕

As described above, the present invention desulfurizes gasified gas at a relatively low temperature range of 350 to 600°C, so there is less carbon precipitation and clogging of the desulfurizing agent can be prevented. Since the sintering of the desulfurizing agent can also be prevented, the desulfurizing agent can be maintained in a highly active state for a long time. In addition, dust removal can be performed at the same time as desulfurization, and the collected dust is burned in an incinerator, and the fluid material with carbon attached is processed in this incinerator.
The carbon can be burned to regenerate and recycle the fluid material, and the energy contained in the flue gas from the incinerator can be recovered and used effectively, so the system as a whole is extremely economical at high temperatures. This has the effect that gasification gas can be purified.

Also, liquid carbonized substances generated during gasification and/or
Alternatively, it is possible to reduce the dust collection load in the dust collection section by attaching or entraining some of the carbon to the fluidized substance of a fluidized bed type gas quenching heat exchanger and burning it in a fluidized bed type incinerator. Furthermore, by returning the fluidized material heated in the fluidized bed type incinerator to the fluidized bed type gas quenching heat exchanger and reusing it, it is possible to improve heat recovery in the gas quenching heat exchanger. is played.

[Brief explanation of the drawing]

The drawing is a flow sheet showing an example of an apparatus for carrying out the high temperature gas purification method of the present invention. 1...Gasifier, 3...Gas quenching heat exchange device,
5... Desulfurization/dust collection device, 7... Fluid medium, 8...
... Heat exchanger tube, 10 ... Desulfurization agent, 13 ... Classifier,
14...Desulfurizing agent regeneration device, 15...Transfer machine, 17
... Incinerator, 22 ... Dry dust collector, 23 ... Turbine, 24 ... Exhaust gas heat exchanger, 25 ... Air compressor, 27 ... Steam drum.

Claims (1)

[Claims] 1. When refining high-temperature gas obtained by gasifying solid hydrocarbons containing sulfur or liquid hydrocarbons containing sulfur, the high-temperature gas is guided to a fluidized bed type gas quenching heat exchanger and cooled to 350 to 600°C. After that, the gas is guided to a moving bed type desulfurization/dust collection device that uses the desulfurization agent as a filter material to desulfurize the gas and remove dust at the same time. A high-temperature gas purification process characterized by incinerating the collected dust in a fluidized bed type incinerator, returning the recycled fluid material to the gas quenching heat exchanger for reuse, and removing dust from the combustion exhaust gas and recovering energy. Method.