Circulating fluidized bed technology in Eunde County, North Korea
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http://www.ln-zn.com/image/煤气化设备1.jpg The circulating fluidized bed technology in Unde County, North Korea, is a relatively advanced and practical coal gasification technology. It was gradually improved and refined over nearly 40 years at the “July 7th” Chemical Plant in Unde County, North Korea, based on the original Winkler pulverized coal fluidized bed gasifier. The design and research unit responsible for further refining and improving this technology is none other than the design and research team of the July 7th Chemical Plant in North Korea, which collaborates with us. The original Winkler gasification technology originated in Germany. It is widely used in countries around the world such as Germany, Japan, the Soviet Union, India, Spain, the Czech Republic, Yugoslavia, North Korea, and China, mainly for producing synthetic ammonia, methanol feed gas, and process gas. At present, this technology has been successfully used in North Korea for nearly 40 years. It has undergone numerous major technical upgrades in production practices, with the defects that arose during operation being addressed one by one, and the original production processes have been optimized. It represents a mature, practical, and relatively advanced new type of coal gasification technology.
Raw material requirements: The raw materials used in the Liaoning Zhongneng gasification process are required to be inexpensive and available in large quantities. The suitable coal types mainly include lignite, long-flame coal, bituminous coal, and other low-quality, non-sticky or slightly sticky young coals; it is necessary that these coals possess good reactivity. http://www.ln-zn.com/image/122.jpg The required specifications for the raw materials are as follows: The particle size of coal should be between 0~10 mm. Its activity level must be greater than 70% at 950℃, and greater than 90% at 1000℃ ； Required moisture content after drying: not more than 12%, with less than 8% being preferred ； Ash content requirement: 10%~40%, with 25% being the upper limit ； Ash fusion point requirement: greater than 1200°C; greater than 1250°C is preferred ； Calorific value requirement: greater than 12.54 MJ/kg; the higher, the better ； Reaction process: http://www.ln-zn.com/image/112.jpg The pulverized coal flows in a bubbling state within the furnace, coming into full contact with the gasifying agent; the coal powder and gases move upward in a swirling motion within the furnace. The reaction of pulverized coal in the gasifier is quite complex. The main reactions are: 2C+O2 → 2CO+Q, C+O2 → CO2+Q, C+H2O→H2 + CO-Q, 2C+H2O+H2→CH4 + CO-Q, C+CO2 → 2CO+Q ……
Process flow: After the raw coal is crushed to meet the required specifications, it is sent to a drying system for drying. Following screening, it is transported using large-inclination wave baffle conveyors, belt conveyors, or bucket elevators, in a fully enclosed manner, to coal storage tanks that are sealed under pressure with CO2 gas. The pulverized coal is then fed into the conical section at the bottom of the gasifier by a screw coal feeder located at the bottom of the coal storage tank. Depending on the gasification application, oxygen-enriched air, pure oxygen, or air can be selected to be mixed with steam and used as a gasification agent, entering the gasification furnace through two routes via a primary nozzle and a secondary nozzle. Coal dust and gasifying agents undergo complex chemical reactions such as decomposition, oxidation, and reduction in the gasifier to produce gas. The reaction temperature is maintained between 950 and 1050°C, while the pressure is kept at 14 to 20 Kpa. The ash resulting from the reaction is discharged from the bottom of the furnace via an internally cooled spiral ash discharge device. http://www.ln-zn.com/image/Gasification_Process flow. jpg The generated gas, unreacted particles, and dust enter two-stage cyclone separators from the top of the furnace; more than 50% of the fly ash in the gas is separated there and returned to the furnace through return pipes for further reaction. The high-temperature gas after sedimentation enters the waste heat boiler to recover residual heat, generating superheated steam. The temperature of the gas at the exit of the superheater is approximately 240°C; it first enters a low-temperature, high-efficiency cyclone, and then passes through a cooling tower, a washing tower, and a Venturi water film dust collector, where its temperature drops to around 45°C. From there, it is sent to the gas tank via the gas pipeline network.
Process parameter: Operating temperature of the furnace – 900–1050°C; it is advisable to keep this temperature at least 150°C lower than that of ST； Operation pressure of the generator: around 0.016 MPa. The pressure at the bottom (nozzle) is approximately 0.03 Mpa; the pressure of oxygen (70% oxygen-enriched air) is also 0.03 Mpa, with a pressure difference between the upper and lower sections of around 2 Kpa ； Carbon content in ash: below 10% ； Mixer temperature: around 150°C ； Temperature of the gasifying agent entering the furnace: around 120°C. Important process parameters
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 2.4–2.7
Oxygen consumption: kNm3/h – 1400
Air consumption: kNm3/h – 0.38
Waste steam production: t/h – 2.0–2.5
Coal feed rate: t/h – 2.7–4.1
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 5000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 4.7–5.3
Oxygen consumption: kNm3/h – 2800
Air consumption: kNm3/h – 0.75
Waste steam production: t/h – 4.4–5
Coal feed rate: t/h – 5.3–8.1
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 10000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 9.3–10.5
Oxygen consumption: kNm3/h – 5600
Air consumption: kNm3/h – 1.4
Waste steam production: t/h – 9–11
Coal feed rate: t/h – 10.5–16
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 20000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 14–15
Oxygen consumption: kNm3/h – 8500
Air consumption: kNm3/h – 2.2
Waste steam production: t/h – 14–16
Coal feed rate: t/h – 15–23
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 30000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 18–20
Oxygen consumption: kNm3/h – 11000
Air consumption: kNm3/h – 2.8
Waste steam production: t/h – 18–22
Coal feed rate: t/h – 20–30
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 40000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 2.4–2.7
Oxygen consumption: kNm3/h – 1400
Air consumption: kNm3/h – 0.38
Waste steam production: t/h – 2.0–2.5
Coal feed rate: t/h – 2.7–4.1
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 5000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 4.7–5.3
Oxygen consumption: kNm3/h – 2800
Air consumption: kNm3/h – 0.75
Waste steam production: t/h – 4.4–5
Coal feed rate: t/h – 5.3–8.1
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 10000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 9.3–10.5
Oxygen consumption: kNm3/h – 5600
Air consumption: kNm3/h – 1.4
Waste steam production: t/h – 9–11
Coal feed rate: t/h – 10.5–16
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 20000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 14–15
Oxygen consumption: kNm3/h – 8500
Air consumption: kNm3/h – 2.2
Waste steam production: t/h – 14–16
Coal feed rate: t/h – 15–23
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 30000 Nm3/h, important indicators for oxygen-enhanced gasification
Unit of measurement: Temperature condition – 900–1050°C
Remarks:
Total steam consumption: t/h – 18–20
Oxygen consumption: kNm3/h – 11000
Air consumption: kNm3/h – 2.8
Waste steam production: t/h – 18–22
Coal feed rate: t/h – 20–30
Calorific value of coal: 3000–5000 kcal/kg
Dust emission: t/h – depends on calorific value and ash content
Gas production rate: m3/kg – 1.3–1.9; depends on coal quality
Gasification intensity: Kg/m2·h – generally greater than 2000
Carbon conversion rate: % – over 90%
Steam conversion rate: % – around 38%
When the furnace load is 40000 Nm3/h, important indicators for oxygen-enhanced gasification
Typical components of gas: Low-calorific value gas (1000 kcal), Medium-calorific value gas (1500 kcal), Ammonia synthesis gas (oxygen-enriched oxidation), Methanol synthesis gas (pure oxygen oxidation), H2 12–1321–2237–4140–41, CO 18–2024–2528–3034–35, CO2 8–914–1517–2020–22, CH4 1–1.52–2.51.5–21.4–2, N2 50–6037–388–100.4–0.5, O2 0.20.20.20.2, H2S 0.10.10.10.1, Dust content in mg/m3
Technical advantages: Lower investment required, as the equipment is entirely domestically produced; the investment needed for similar scale is only 30%–50% of that required for imported gasification units. < High gasification efficiency, high gasification intensity, and gas quality meets the requirements. The gasification efficiency can reach 72%–76%. < The production cost is low, as the raw materials used are inferior coals such as lignite; their prices are much lower compared to anthracite and coke. Additionally, the transportation distance is short, which results in a significant reduction in the cost of gas production. < The technology is mature and reliable, suitable for large-scale production. The production capacity per furnace is: 5000 Nm3/h, 10000 Nm3/h, 20000 Nm3/h, 30000 Nm3/h, 40000 Nm3/h. < It has a wide range of coal type compatibility, suitable for lignite, bituminous coal, and non-sticky or weakly sticky coals, allowing for complete localization of raw materials. < It has a low environmental impact; due to the high reaction temperature, the pyrolysis reaction is relatively complete, with no tar or residue, and the purification system is simple and pollution-free. < It generates a large amount of steam; 5.5 tons of steam can be produced per 10,000 cubic meters of gas, with 80% used internally and 20% supplied externally. < It offers high operational flexibility; the production load of the vaporization furnace can be adjusted within the range of 60% to 110% of the design load. < Easy to start and stop the furnace; after stopping the gasifying agent and pulverized coal, the furnace can be shut down within a few minutes ； The fluidized bed cools down slowly, and gasifying agent can still be introduced after a few days to restart it. < It features stable and reliable operation, requires minimal maintenance, and has a simple structure; as a result, it can achieve a high continuous operation rate with little need for maintenance, with an operation rate of over 92%. < It solves problems such as excessive dust in similar systems and difficulties in handling slag water.
The main equipment of the Liaoning Zhongneng circulating fluidized bed coal gasification unit includes: coal powder hoppers, intermediate coal storage tanks, coal storage tanks, mixers, gasifiers, screw coal feeders, coal gas generators, primary reflux cyclones, secondary cyclones, water-cooled screw slag removers, ash settling chambers, waste heat boilers, steam superheaters, high-efficiency combined cyclones, washing and cooling towers, Venturi tube dust collectors, gas-water separators, U-shaped water seals, flares, exhaust fans, feed water pumps, coal gas pipes, ash discharge pipes, return pipes, bellows, as well as coal drying systems and coal feeding systems, among others. http://www.ln-zn.com/img/总体.jpg General Overview
http://www.ln-zn.com/img/旋风除尘.jpg Cyclone Dust Removal
http://www.ln-zn.com/img/煤气发生炉.jpg Gas Generator
http://www.ln-zn.com/img/废热锅炉.jpg Waste Heat Boiler
http://www.ln-zn.com/img/储煤槽.jpg Coal Storage Silo
http://www.ln-zn.com/img/旋风除尘.jpg Cyclone Dust Removal
http://www.ln-zn.com/img/煤气发生炉.jpg Gas Generator
http://www.ln-zn.com/img/废热锅炉.jpg Waste Heat Boiler
http://www.ln-zn.com/img/储煤槽.jpg Coal Storage Silo