JPH0242877B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an apparatus for removing dust, removing tar, and recovering waste heat from high-temperature gas produced in a coal gasifier.

<Conventional technology and its problems> The gas generated by the gasifier for coal gasification is 800 to 1000
At high temperatures (°C), the gas contains dust such as undecomposed coal and ash, and by-product tar, and in order to effectively use the gas as fuel gas, etc., it is necessary to cool the gas, remove dust, and remove tar. Furthermore, during cooling, it is necessary to recover waste heat by effective means. i.e. 800～
It is best to use a fluidized bed and heat transfer tubes, which have good heat transfer efficiency, to cool high-temperature gas at 1000℃, but as mentioned above, this gas contains dust and tar oil droplets, so if it is cooled excessively, tar particles will form on the outside of the heat transfer tubes. There is a problem in that the particles adhere to the fluid, inhibit heat transfer, and stick to the fluidized medium, forming small lumps that make it impossible to operate the fluidized bed.

Therefore, its structure and operation must be within a certain temperature range. In addition, if the gas being sent out is at a high temperature, the particles in the moving layer with tar attached to it will become hot in the subsequent dust removal equipment, which will cause major problems in the selection and design of equipment for the accompanying particle regeneration system. .

In addition, in order to supply the regenerated particles to the dust removal device and the fluidized bed cooler, a regeneration furnace for incinerating and removing tar and a lift device as a means for returning the regenerated particles are required.

Even if most of the dust is removed, a cooling device is required to further cool down the ultrafine particles of tar oil into liquid form and send them out together with the gas. Scrub (clean) any tar oil microdroplets that still remain.
It must be removed by some means.

In order to remove tar oil that adheres to equipment under such temperature conditions of 800 to 1000°C, there has been no suitable means that satisfies the above conditions.

A device for recovering heat from gas from a coal gasification furnace, which is high-temperature gas containing tar and dust, as described above is disclosed in JP-A-54-86848 (referred to as the cited invention).
It has been known.

This cited invention describes that the area above the pipe grid 6 is a fluidized bed at a temperature of 610°C to 800°C depending on the operating conditions, and the area below it is a fluidized bed or a fixed bed at a temperature of 870°C to 950°C.

However, if tar adheres to the fluidized particles, they will form small lumps and settle downward, and if they are made into a fixed bed, there is a chance that the center will not burn and form into large lumps. Also
There are no suitable heat-resistant materials for the related equipment to transport particles at temperatures between 870°C and 950°C, and there are many problems such as cooling the equipment. Also, this device is 870℃
No means of cooling the high temperature particles of ~950°C is provided.

<Summary of Means> In short, this invention has an intralayer heat exchanger tube that is maintained at a temperature higher than the temperature at which particles do not adhere to each other due to adhesion of dust, tar, etc. from upstream to the flow of high-temperature generated gas of a coal gasifier. Fluidized bed cooler, a moving bed granular bed filter that filters and removes dust, tar, etc., a gas cooler with a heat transfer tube whose tube wall is maintained at a temperature higher than the flow limit temperature of the tar, and a gas cooler that flows downstream from this gas cooler. It consists of a scrapper that uses cooled tar oil for cleaning and cooling collection, and a waste heat boiler that includes a pipe line for the circulating tar oil, and extracts and regenerates particles from the fluidized bed cooler and granular bed filter. The present invention is characterized in that it is a dedusting and cooling device for coal cracked gas, which is equipped with a particle regeneration furnace and a means for returning the recycled particles.

<Object of the invention> The object of the invention is to propose a process device that can remove dust and gas containing tar at a high temperature of 1000°C, cool it, and send it out.

<Example> As shown in Fig. 1, high-temperature generated gas sent out from a coal gasifier is supplied to a fluidized bed cooler 4 through a pipe 3, and is poured into a fluidized bed in which built-in alumina particles of 1 to 2 mmφ are fluidized. is where the heat transfer tube 10 through which the boiler water from the high-pressure boiler drum 5 flows is located, 60 to 100
Kg/cm ² g of steam is generated, and the temperature is 400 to 500 to prevent particles from adhering to each other and clumping together due to adhesion of dust, tar, etc.
Cool the gas to ℃.

The gas containing tar mist and dust is then sent to a moving bed type granular bed filter 16.

In this granular bed filter (hereinafter referred to as filter 16), alumina particles are accommodated between two shutter-type plates, and while gas flows between the particles in this moving layer, dust is removed and tar is removed by collision. As the amount of dust and tar collected increases with the passage of time, the ventilation resistance increases, and the alumina particles are extracted by the lower rotary valve 19, so that a moving layer is formed in the filter 16.

The tar oil and alumina particles with dust attached thereto extracted from the fluidized bed cooler and filter 16 are processed in a regeneration furnace 24. The regeneration furnace is a fluidized bed incinerator that fluidizes the particles with combustion air 30, uses tar oil from the pipe 53 as an auxiliary fuel, and burns the dust and particles attached to the surface with its help. Then, it is extracted again through the over-blow pipe 25 and transferred to the hopper 20 at the top through the blow-up pipe 28 using compressed air from the pipe line 27 using the blow-up device 26. The compressed air is separated from the particles and exhausted through line 29.
The regenerated particles are again supplied to the fluidized bed cooler and granular bed via rotary valves 22 and 23 and supply pipes 14 and 21. The dedusting gas is further cooled in the cooler 36 to the extent that it flows down along the cooling pipe and wall surface, and is then passed through the scrubber 4 directly connected to it through a short pipe 43.
4 for cleaning (scrubbing). The cooler 36 is composed of a boiler drum 40, a rising pipe 38, a downcomer pipe 39, and a heat transfer pipe 37, and the water supply 41 is turned into medium pressure steam 42 and is sent to the outside of the system. The medium-pressure steam conditions were selected so that the gas temperature after cooling is sufficiently higher than the temperature at which the tar condenses and solidifies, and at an appropriate saturation temperature or saturation pressure so that the gas contact surface of the heat exchanger tube is at a uniform temperature. This is the purpose of choosing. As one of the design examples, a steam pressure of 15 Kg/cm ² g is selected as the gas temperature after cooling is 250°C and the temperature of the rear wall of the heat exchanger tube is 200°C or higher.

Regarding the scrubber 44, recovered tar with a low temperature is injected directly into the scrubber from a conduit 45 to further cool the gas and scrub the tar at the same time.
At step 7, gas and liquid are separated, and the cleaned gas is sent to the outside of the system through a pipe 48, and the recovered tar is sent to a tar pot 50 through a pipe 49. scrubber 4
4, a considerable amount of tar is injected to cool the gas. Therefore, the piping 51, the pump 52, the low pressure boiler 54, and the piping 45 also circulate tar oil for scrubbing. Excess tar goes to pipe 5
3 and used as auxiliary fuel for the regeneration furnace. The bed layer of the granular bed 16 can be installed in two or more stages to increase the dust removal efficiency, but there is a limit to the dust collection efficiency, so the scrubber 44 is used to improve the final dust removal effect. This is also one of the features of this invention.

Since the tar temperature in the tar pot 50 where the tar is temporarily stored is the same temperature as the generated gas 48, a waste heat boiler 5 is installed to improve the cooling performance of the scrubber.
Step 4 cools the tar. As a design example, the waste heat boiler inlet temperature is 250°C and outlet temperature is 150°C. Therefore, the steam 57 generated in the drum 55 has a low pressure of about 3 kg/cm ² g. As another example, if the waste heat boiler is replaced with a water cooler, the heat transfer tube is dominated by water temperature, which becomes lower than the condensation temperature of tar and causes solidification of tar, so in this case it is absolutely necessary to use a low pressure boiler.

<Effects of the Invention> In short, in this invention, the fluidized bed cooler lowers the gas temperature to 400 to 500°C and ensures flow. By selecting this temperature, the material of the equipment downstream of the gas flow is made of an exceptionally high temperature heat resistant material. The granular bed filter is a moving bed type, making it easy to remove and replenish particles to remove tar adhesion and dust, and remove the particles from the tar in a regenerator. Tar oil can be removed and regenerated for cyclic use, tar oil can be used for scrubbing, and some can be used as an auxiliary fuel. This enables the construction of a process for treating gas from a high-temperature, dust-containing coal gasifier that is connected in a sticky manner.

By carrying out this invention, in a coal gasification plant, the dust and tar contained therein can be effectively removed by the fluidized bed and moving bed media without reducing the filter effect, and the tar adhering particles are incinerated and heated. The collected tar oil is used to remove tar mist through scrubbing and as a fuel oil. High pressure, medium pressure, and low pressure steam is obtained through heat recovery and is used as the steam required by the plant, enabling continuous operation for more than 90 days. It has various effects such as.

[Brief explanation of the drawing]

FIG. 1 is a diagram of an apparatus and piping system according to the present invention. 1...Coal gasifier, 4...Fluidized bed cooler,
5... High pressure boiler drum, 16... Granular bed filter (dust remover), 20... Particle supply hopper, 24... Particle regeneration furnace, 36... Cooler, 40... Medium pressure boiler drum, 44... ...Tar scrubber, 50...Tarpot, 54...
low pressure boiler.

Claims (1)

[Claims] 1. Regarding the flow of high temperature generated gas of a coal gasifier,
A fluidized bed cooler with an internal heat exchanger tube that is maintained at a temperature higher than the temperature at which particles do not adhere to each other and become lumps due to the adhesion of dust, tar, etc. from upstream, a moving bed granular bed filter that filters and removes dust, tar, etc. A gas cooler with a heat transfer tube whose tube wall is maintained at a temperature higher than the flow limit temperature of the gas cooler, a scrubber that circulates and uses the tar flowing down from the gas cooler, and a scrubber that cleans and cools the tar oil for collection, and a circulating tar oil. It consists of a waste heat boiler including a pipe line,
A dedusting cooling device for coal cracked gas, further comprising: a particle regeneration furnace for extracting and regenerating particles from the fluidized bed cooler and granular bed filter; and means for returning the recycled particles. 2. Coal cracking according to claim 1, characterized in that the heat transfer tubes of the high pressure boiler are located in a fluidized bed cooler, and the heat transfer tubes of the intermediate pressure boiler are located in a gas cooling system, so that the waste heat boiler is a low pressure boiler. Gas dedusting cooling device.