WO2014026637A1

WO2014026637A1 - Apparatus and method implementing carbon dioxide capturing in lime production process

Info

Publication number: WO2014026637A1
Application number: PCT/CN2013/081631
Authority: WO
Inventors: 白玉龙; 王昀睿
Original assignee: 西安瑞驰节能工程有限责任公司
Priority date: 2012-08-17
Filing date: 2013-08-16
Publication date: 2014-02-20
Also published as: CN102786236B; CN102786236A

Abstract

Related are an apparatus and method for implementing carbon dioxide (CO₂) capturing in a lime production process. The apparatus comprises a crusher and a vibrating screener. The vibrating screener is connected to a metering apparatus via a material-feeding belt. The metering apparatus is in communication with a closed calciner. The closed calciner is connected respectively to a cooler and a lime storage tank. The cooler is in communication with a dedusting and purification apparatus. The dedusting and purification apparatus is connected sequentially to a compressor and a condenser then is in communication with a CO₂ storage tank. The method comprises: limestone is crushed and screened, then conveyed to the metering apparatus via the material-feeding belt; when metered, the limestone is conveyed into the closed calciner for lime calcination; decomposition component CaO is conveyed to the lime storage tank; and highly concentrated CO₂ generated from decomposition is cooled and dedusted, then compressed and condensed to be converted into liquid CO₂, and is finally stored. The capturing of large quantities of CO₂ generated during limestone calcination in the lime production process not only reduces a large amount of greenhouse gas emissions, but also recycles CO₂ product, and has a broad application prospect.

Description

Apparatus and method for realizing carbon dioxide capture in lime production process

The present invention relates to an apparatus and method for carbon dioxide capture, and more particularly to an apparatus and method for carbon dioxide capture in a lime production process by isolating air calcination.

Background technique

Lime, also known as quicklime, is mainly used in the construction, chemical, calcium carbide, metallurgical and other industries. The production process of lime is an endothermic reaction, which is to calcine limestone at a high temperature to decompose the main component of the limestone, and to eliminate the decomposed carbon dioxide. The principle is as follows:

CaC0 ₃ ( s) ~→► CaO ( s) +C0 ₂ (g) -176.68 kJ

(...1) It can be seen from the formula α) that the production process of lime is inevitably accompanied by the discharge of a large amount of carbon dioxide gas, and the output ratio is roughly lime (54): carbon dioxide (43). Based on the current annual production of 300 million tons of lime in China, the annual production of carbon dioxide in calcined limestone production is about 238 million tons. Carbon dioxide is one of the main components of greenhouse gases that cause global climate change. The contribution rate to the greenhouse effect is as high as 55%. Climate change caused by greenhouse gas emissions such as carbon dioxide has become a focus of attention around the world. At the same time, carbon dioxide is an industrial raw material with many uses, and it is widely used in food processing, beverage, fertilizer, fire prevention, oil exploitation and other industries. It is very important to capture a large amount of carbon dioxide generated during the calcination of limestone to reduce the amount of greenhouse gases and recover economical carbon dioxide products.

The existing lime kiln is mainly a rotary kiln, a common shaft kiln or a double shaft kiln. Limestone and fuel (gas fuel is fed through the pipeline and burner) are put into the lime kiln, and the limestone is preheated to 850 °C. The decomposition started, and the calcination was completed at 1200 ° C, and the generated lime was cooled and discharged to the outside of the kiln. Except for a very small number of lime production units, carbon dioxide recovery technology is used at the back end of the lime kiln, and carbon dioxide recovery equipment is built in the kiln. The carbon dioxide produced is discharged into the atmosphere. One side, the existing lime kiln in the process of transportation, fuel burning in the kiln, will produce a large amount of combustion fumes and harmful gas products such as sulfur dioxide, nitrogen oxides, carbon monoxide, etc., bringing great difficulties to the separation of carbon dioxide; On the other hand, the existing carbon dioxide capture and recovery technologies mainly include chemical absorption method, physical absorption method, pressure swing adsorption method, and membrane adsorption method. In either case, the purification-absorption-desorption-collection process is required. Complex, such as the commonly used chemical absorption technology involves a complete set of dust collectors, scrubbers, desulfurization towers, absorption towers, desorption towers, storage tanks, compressors, drying liquefaction systems, liquid storage tanks, filling systems, etc. Equipment, in addition, due to the limitation of carbon dioxide concentration in the flue gas (about 20-30%), there are problems such as low efficiency, large equipment maintenance, and high production cost when using the above method for carbon dioxide recovery.

Summary of the invention

In view of the deficiencies in the prior art described above, it is an object of the present invention to provide an apparatus and method for carbon dioxide capture in a lime production process by isolating air calcination. The device has compact structure, low investment intensity, low operating cost and good industrial application prospects. The method implemented by the device has mature process conditions and simple steps, and can efficiently capture co ₂ produced during limestone calcination to produce lime.

In order to achieve the above object, the technical solution provided by the present invention is:

Providing an apparatus for realizing carbon dioxide capture in a lime production process, comprising a crusher for crushing limestone, and a vibratory screening machine for screening the crushed limestone, the vibratory screening machine connecting the metering device through the loading belt, The metering device is connected to the closed calcining furnace; the sealed calcining furnace is respectively connected with the cooler and the lime storage tank, and the cooler is connected with the dust removing and purifying device, and the dust removing and purifying device is connected to the compressor and the condenser through the pipeline in turn, and is stored with the co ₂ The tanks are connected.

Preferably, the sealed calcining furnace comprises a closed feeding device, a closed ash discharging device, a (0 ₂ discharge port and a radiant heating device, the closed feeding device is disposed above the side wall of the closed calcining furnace, and is connected to the metering device outlet The closed ash discharging device is disposed under the closed calcining furnace and is opposite to the lime storage tank; the 0 ₂ discharge port is disposed above the other side wall of the closed calcining furnace, and is connected to the cooler through the pipeline through.

Preferably, the cooler is connected to a cooling tower, and the cooling tower and the cooler medium outlet respectively The concave media inlets are connected.

Accordingly, the present invention also provides a method of achieving carbon dioxide capture during lime production, the method comprising the steps of:

1) The limestone is first crushed by a crusher, and the crushed limestone is sieved by a vibrating screening machine, and then conveyed to a metering device through a feeding belt;

2) After the metering device measures the crushed and sieved limestone according to the mass ratio, it is transported to the insulated air-tight calciner through the closed cloth device for lime calcination;

3) CaO decomposed by high-temperature calcination in the kiln is transported to the lime storage bin through the sealed ash device;

4) Further, the high concentration C0 ₂ generated by the decomposition is sent to the dust removal and purification device through the cooler for purification treatment;

5) The high concentration after purification (0 ₂ after the compression and condensation process, the liquid C0 _{2 is} stored in the C0 ₂ storage tank.

Preferably, in the method, the limestone has a particle size of 10-80 mm after being crushed.

Preferably, in the method, the high concentration of CO ₂ is cooled by heat exchange in a cooler through a cooling medium, and the cooled CO ₂ temperature is 50-100 ° C.

The method and apparatus provided by the invention have the following beneficial effects: (1) Compared with the prior method, the method provided by the invention adopts calcination of CaCO ₃ under completely isolated air, and the purity of the captured CO _{2 is} up to 99%. The above is beneficial to the subsequent utilization and treatment of C0 ₂ ; (2) The process flow is simple, (0 ₂ capture integration is low, corrosion to the system is small, energy is saved; (3) cooling system closed cycle, cooling medium recycling, greatly reduced Operation and maintenance costs.

DRAWINGS

1 is a flow chart of an apparatus for carbon dioxide capture in a lime production process by insulating air calcination according to an embodiment of the present invention;

2 is a process flow diagram of an embodiment of the present invention.

In the figure: 1. Material crusher; 2. Vibratory screening machine; 3. Feeding belt; 4. Metering device; 5. Closed calciner; 5a, closed feeding device; 5b, closed ash device; 5c, C0 ₂ Discharge port; 5d, radiant heating device; 6, cooler; 7, dust removal and purification device; 8, compressor; 9, condenser; 10, C0 ₂ Storage tank; 11, lime storage silo; 12, cooling tower.

detailed description

The process of the apparatus of the present invention and the process for performing carbon scavenging by lime gas production using the apparatus for insulating air calcination will be described in detail below with reference to the accompanying drawings and embodiments.

Figure 1 shows an apparatus for carbon scavenging in lime production by means of isolated air calcination, comprising a crusher 1 for crushing limestone, and a vibrating screen 2 for screening crushed limestone, wherein the vibrating screen 2 The loading belt 3 is connected to the metering device 4, and the crushed and sieved limestone is sent to the metering device 4, and the metering device 4 is connected to the closed calcining furnace 5, and the metered limestone is transported to the closed calcining furnace 5, and the calcined furnace is sealed. The furnace 5 is connected to the cooler 6 and the lime storage tank 11, respectively; wherein the sealed calciner 5 comprises a closed feeding device 5a, a closed ash discharging device 5b, a C0 ₂ discharge port 5c and a radiant heating device 5d, and the closed feeding device 5a is provided Above the side wall of the sealed calcining furnace 5, and opposite to the outlet of the metering device 4; the sealed ash discharging device 5b is disposed below the sealed calcining furnace 5 and is in contact with the lime storage bin 11; the C0 ₂ discharge port 5c is disposed It is above the other side wall of the closed calciner 5 and is in communication with the cooler 6 through a pipe. The cooler 6 communicates with the dust removing and purifying device 7, and the dust removing and purifying device 7 sequentially connects the compressor 8 and the condenser 9 through a pipe, and then communicates with the C0 ₂ storage tank 10.

In a specific embodiment, the cooler 6 is connected to a cooling tower 12 which is connected to the cooler 6 medium outlet and the recovery medium inlet, respectively.

In a specific embodiment, the inlet of the metering device 4 is docked with the loading belt 3 and the outlet of the metering device 4 is docked with the closed feeding device 5a.

In a specific embodiment, the inlet of the vibrating screen 2 is docked with the outlet of the material crusher 1, and the outlet of the vibrating screen 2 is docked with the loading belt 3.

In a specific embodiment, the cooler 6 is connected to a CO ₂ gas collecting port on the closed calcining furnace 5 for isolating air, and the inlet of the dust removing and purifying device 7 is connected to the outlet of the cooler 6.

In a specific embodiment, the cooler 6 is a water-cooled heat exchanger, and the cooling tower 12 is connected to the cooler 6 hot water outlet and the recovery cooling water inlet, respectively.

As shown in Figure 2, the workflow corresponding to the above device is as follows: The method includes a step of saying:

1) First, the limestone is crushed by the crusher 1, and the crushed limestone is sieved by the vibrating screening machine 2 to obtain a limestone product having a particle size of 10-80 mm, which is conveyed by the feeding belt 3 to the measuring device 4;

2) The metering device 4 measures the crushed and sieved limestone product according to the mass ratio, and then conveys it to the closed calcining furnace 5 which is insulated by the air through the closed cloth device 5a to perform lime calcination;

The closed calciner 5 is divided into a preheating zone, a calcining zone and a cooling zone. The crushed and sieved limestone is preheated and then calcined at a temperature of 1000-1400 ° C; the kiln is completely insulated from the outside air. The production system, under high temperature calcination in the kiln, the limestone is decomposed into CaO and very high purity C0 ₂ gas, and then cooled at a temperature of 300-400 ° C;

3) CaO decomposed by high-temperature calcination in the kiln is transported to the lime storage bin 11 by the closed ash discharging device 5b in the closed calcining furnace 5;

4) The high concentration of C0 ₂ gas generated by decomposition is 300-400 °C, and the high concentration C0 ₂ generated by decomposition is sent to the cooler 6 through the heat-resistant pipe for cooling, and the temperature of the gas after cooling is lowered to 50-100 ° C. After the heat exchanger 6 exchanges heat, the cooling water is heated to 80-90 ° C, the hot water is sent to the cooling tower for cooling and returned to the cooler 6; the high concentration C0 ₂ after water-cooling heat transfer is sent to the dust purification The device 7 performs a dust removal process;

5) dust purification device 7 the cooled gas is further purified to a concentration of 98.0-99.8% high purity gas, via a high dust concentration after treatment ₍₀₂ through compressor 8, a condenser 9 to a liquid C0 ₂ The finished product is transported from a closed pipe to a (0 ₂ storage tank) for subsequent use.

The high concentration of CO ₂ generated by the above decomposition can be directly transported to the C0 ₂ storage tank, or can be injected into deep saline, depleted oil and gas fields, poor coal seams or oceans for storage, and subsequently used in food processing, beverage, fire prevention and other fields.

The above-mentioned limestone crushing, sieving and other pretreatment steps are required to meet the requirements of the subsequent closed feed and calcination system to block the air.

The limestone metering step described above for metering limestone entering the insulated air calcination system The above-mentioned purifying and dedusting step is performed to remove CaC0 ₃ , CaO and other impurities contained in the co ₂ gas generated by the insulating gas calcining system.

The above-mentioned C0 ₂ cooling, compression, condensation and the like, the corresponding treatment of the ₀₂ gas generated by the isolated air calcination system is made to better meet the requirements of the subsequent storage (sealing).

The above-mentioned cooling medium recovery system cools the heat-exchanged water and returns it to the CO ₂ cooling step to save fresh water consumption.

The above is a detailed description of the present invention in conjunction with the specific preferred embodiments. It is not to be understood that the specific embodiments of the present invention are limited thereto, and those skilled in the art to which the present invention pertains, without departing from the scope of the present invention. In the following, a number of simple derivations or substitutions may be made, which should be considered as belonging to the scope of patent protection as defined by the appended claims.

Claims

claims

1. An equipment for capturing carbon dioxide in the lime production process, including a crusher (1) for crushing limestone, and a vibrating screener (2) for screening the crushed limestone, characterized in that: The vibrating screening machine (2) is connected to the metering device (4) through the feeding belt (3). The metering device

(4) is connected to the closed calcining furnace (5); the closed calcining furnace (5) is connected to the cooler (6) and the lime storage bin (11) respectively, and the cooler (6) is connected to the dust removal and purification device (7) , the dust removal and purification device (7) is connected to the compressor (8) and the condenser (9) through pipelines in sequence, and is connected to the CO ₂ storage tank (10).

2. The equipment for capturing carbon dioxide according to claim 1, characterized in that the sealed calcining furnace (5) includes a sealed feeding device (5a), a sealed ash discharge device (5b), and a CO ₂ discharge port (5c ) and a radiation heating device (5d), the sealed feeding device (5a) is arranged above the side wall of the sealed calcining furnace (5) and is connected to the outlet of the metering device (4); the sealed ash discharge device (5b) ) is arranged below the sealed calcining furnace (5) and is connected to the lime storage bin (11); the CO ₂ discharge port (5c) is arranged above the other side wall of the sealed calcining furnace (5) and passes through the pipeline Connected to cooler (6).

3. The carbon dioxide capture equipment according to claim 1, characterized in that the cooler (6) is connected to a cooling tower (12), and the cooling tower (12) is connected to the medium outlet of the cooler (6) respectively. Connected to the recycling medium inlet.

4. A method for capturing carbon dioxide during lime production, characterized in that the method includes the following steps:

1) First, crush the limestone through the crusher (1). The crushed limestone is then screened by the vibrating screener (2) and then transported to the metering device (4) through the feeding belt (3);

2) After the crushed and screened limestone is measured according to the mass ratio by the measuring device (4), it is transported to the closed calcining furnace (5) through the closed distribution device (5a);

3) Limestone is calcined and decomposed at high temperature in the closed calcining furnace (5), and the generated CaO is transported to the lime storage bin (11) through the closed ash discharge device (5b);

4) The high-concentration 0 ₂ generated by the high-temperature calcining and decomposition of limestone is transported to the dust removal and purification device (7) through the cooler (6) for dust removal treatment; 5) After dust removal, the high-concentration ( ₀₂ ) is compressed and condensed to obtain liquid _CO2 and seal it in a _CO2 storage tank.

5. The method for capturing carbon dioxide in the lime production process according to claim 4, characterized in that the particle size of the crushed limestone is 10-80 mm.

6. The method for capturing carbon dioxide in the lime production process according to claim 4, characterized in that the high concentration (0 ₂₎ is cooled after heat exchange with the cooling medium in the cooler, and the cooled CO ₂ temperature is 50-100 °C.