Dry distillation of bulk oil shale usually uses hot gas or hot dry distillation gas as a gas heat carrier to enter the dry distillation furnace to heat the dry distillation oil shale. Because the heat transfer coefficient of shale block itself is small, the heat transfer rate from the surface of shale block to its center is slow, so the time required for dry distillation is about several hours. At present, each Fushun-type lump oil shale retort used in industrial production has a daily output of 65,438+000 tons of oil shale; There are Kievit furnaces in Estonia, each of which processes 200t and 1000t oil shale every day. Brazil has Petrossex furnaces, each of which processes 1500t and 6000t oil shale every day.
Granular shale dry distillation usually uses heated shale ash as solid heat carrier, which is mixed with shale for heating dry distillation. Granular shale takes only a few minutes or more because of its small particles and rapid temperature rise. The heat source of solid heat carrier usually comes from shale dry distillation gas or hot flue gas produced by shale semi-coke combustion. At present, granular shale retorts used in industrial production include Glot furnaces in Estonia, and each retort processes 3000 tons of oil shale every day. In addition, Tasek Granular Shale Distillation Furnace (ATP) developed by Canada has been expanded to process 6000 tons of oil shale every day in Australia.
Dry distillation of powdered shale is usually mixed with hot shale ash powder in fluidized state for dry distillation and oil refining. The source of hot shale ash usually comes from fluidized combustion of shale coke. The fluidizing agent used for fluidized dry distillation is usually steam or dry distillation gas. Because of the small particle size of silty shale, the time required for dry distillation is only about 2 ~ 3 minutes. The dry distillation temperature is generally 450℃. The biggest advantage of the powder shale retort is its high retort strength, but the oil and gas produced by the retort in fluidized state is easy to bring out more dust when it is discharged, which is difficult to treat.
The shale used in the massive shale retort needs to be crushed to a certain extent, but the raw oil shale is mined from the mine, and after a certain degree of crushing and screening, it will produce 10% ~ 20% fine particles, which can not be used in the massive shale retort, causing losses. However, the granular or powdery shale retort can crush and screen all the mined shale to the required granularity and make full use of it, which will not lead to the waste of raw materials.
Figure 3-2 Fushun retort furnace
1 Fushun retort
Fushun massive shale retort, also known as Fushun internal heat retort,
Fushun furnace for short (Figure 3-2). Fushun retort is one of the four largest retorting processes for oil shale in the world, which was formed in 1930s, developed in 1950s and matured in 1960s. Fushun furnace is the connection point between oil shale dry distillation and shale semi-coke gasification.
The vertical cylindrical massive shale retort furnace has a retort section at the upper part and a gasification section at the lower part together. Fushun furnace processing 12 ~ 75 mm massive oil shale. The heat required for dry distillation is provided by two heat sources: ① the high-temperature gas generated by gasification and combustion of shale semi-coke and the air (main air) containing saturated steam introduced from the bottom of the furnace enter the dry distillation section upwards to heat the shale, which is the first heat source; (2) In addition, the hot circulating gas heated by the heat storage furnace outside the retort furnace is introduced into the middle of the retort furnace and enters the retort section upward to heat the shale, which is the second heat source of the shale retort furnace. Fushun furnace adopts water washing cooling method. Fushun furnace can utilize the fixed carbon in shale semi-coke, and the heat can be self-sufficient when processing low-grade oil shale (with oil content above 6%). After long-term industrial production test, it is an oil shale retort with good economy and high reliability.
Fushun furnace uses a set of condensation recovery system for every 20 sets of equipment, which is called "Department". Each furnace processes 2000 tons of massive oil shale every day, with an annual output of 3× 104 tons of shale oil.
Fushun furnace has the advantages of simple structure, durable equipment, convenient maintenance and operation management, suitable for low-grade oil shale, large-scale industrial production and long start-up period (350d/a).
The disadvantage of Fushun furnace is that the amount of ore treated is small (100t/d), and the oil yield can only be 65% of that of aluminum retort. Only 12 ~ 75 mm oil shale particles can be treated, and the resource utilization rate is low; The degree of system automation is low, the control system is backward, and the labor intensity of operators is high; The problem of environmental pollution, especially air pollution, has not been completely solved. These shortcomings restrict the development and popularization of Fushun furnace.
In order to overcome the above shortcomings, in recent years, the shale refinery of Fushun Mining Group has studied the upgrading scheme of Fushun furnaces and prepared to upgrade its existing 9 furnaces. At the same time, since 2006, Fushun Mining Group Shale Refinery has also cooperated with Shaanxi Metallurgical Design and Research Institute to develop a new shale oil recovery process. While retaining the advantages of Fushun retort furnace, the new process transplanted and used a number of advanced, mature and efficient technical equipment in metallurgical gas production, and optimized its traditional oil shale retort process. The new technology has been successfully used in small industrial test equipment. Since then, in Fushun Group's E-part oil shale refining technical transformation project with an annual processing capacity of 200× 104t and an annual production capacity of 8× 104t, new technologies have been adopted for construction. The oil shale refining project in Area E consists of 40 Fushun furnaces, and a set of condensation recovery system is adopted. The project started in June 2007 and was put into operation smoothly in September 2008. The automation degree of the new process is obviously improved; The highest oil yield is 80%, which is 10% ~ 15% higher than that of the traditional process, which is close to the international advanced level. Less waste water is generated, which is more environmentally friendly; The volume is reduced by half, which is more energy efficient. The new technology has basically achieved the expected goal of energy saving, high efficiency and environmental protection.
2. Maoming round furnace
Maoming round furnace is similar to Fushun furnace, and it is also an internally heated massive shale retorting furnace with gasification section. The main difference from Fushun furnace structure is that the middle part of the retort furnace adopts a mixing chamber with a multi-faceted gas distribution structure. The process flow is the same as Fushun furnace. Oil shale is fed from the top of the furnace, and then is retorted and gasified in sections in the furnace, and the main air enters the bottom of the furnace. The fixed carbon in shale semi-coke is burned and gasified in the gasification section, which provides part of the heat needed for oil shale dry distillation, and the rest is provided by hot circulating gas. The gas generated in the gasification section is mixed with the hot circulating gas, sprayed from the spray hole in the middle of the dry distillation section for heating, and flows upward to contact and exchange heat with the oil shale in countercurrent, so as to dry distillation. Dry distillation products are extracted from the top of the furnace and shale ash is discharged from the bottom of the furnace. The daily processing capacity of oil shale ore is 100t, and the oil yield is 65% of that of aluminum retort (Luo,1991; Lin, 1988).
Figure 3-3 Maoming Square Furnace
3. Maoming Square Furnace
Maoming Fangzan was first used in 1960s. Maoming square furnace, also known as Maoming gas square furnace, is an internally heated massive oil shale retorting furnace, which uses circulating gas to provide heat for retorting oil shale (Figure 3-3). The evenly mixed circulating gas and air enter the middle of the furnace, and the combustion and reduction reactions are carried out in the high-temperature shale semi-coke layer, and the heat required for the dry distillation of oil shale is provided by the high-temperature gas heat carrier generated by the reaction. Using gas heating method, there is enough heat and thick high temperature layer in the furnace to ensure that oil shale is fully retorted. The daily processing capacity of 300 tons of oil shale is slightly higher than that of Maoming ring furnace, which is about 70% of that of aluminum retort furnace.
The cold circulating gas with saturated steam introduced from the bottom of the furnace can not only exchange heat with the high-temperature shale ash to recover most of its sensible heat, but also reduce the temperature of the ash discharged from the bottom of the furnace to below 300℃, and its steam can be partially reduced with the fixed carbon in the high-temperature shale semi-coke at the upper part of the ash cooling section, which is beneficial to the improvement of gas calorific value (Luo,191; Lin, 1988).
In 1990s, Sanjiang Coal Chemical Company of Shenmu County transformed Maoming square retort furnace into SJ square vertical retort furnace, which was applied to Shenmu coal retort process. Shenmu Sanjiang Coal Chemical Company owns SJ square retort pilot plant (ore processing capacity 1t/h) and industrial plant (ore processing capacity 10t/h, 20t/h), and has nearly 20 years of technical development experience. At present, more than 300 SJ square retort furnaces with different models have been put into production, and SJ square retort furnaces with different processing capacity have been widely used in Shaanxi.
At present, SJ square retorting furnace has been successfully applied to oil shale retorting process. Two different types of oil shale were tested, and the average oil yield was above 80%. The requirement of SJ square retort for oil shale particles is 8 ~ 60 mm
4. Estonia Kievit refutes.
Kiviter retort is vertical and cylindrical (Figure 3-4), and it processes massive oil shale. The furnace consists of a steel plate shell and a refractory lining. There are rectangular combustion chambers in the middle of the upper part of the furnace and on both sides of the middle part of the furnace. A burner introduces air and dry distillation circulating gas for combustion. The generated hot flue gas transversely enters two rectangular retort chambers with parallel cross sections at the upper part of the furnace, and the oil shale is heated from top to bottom (forming thin-layer retort), and the generated oil and gas is led out through the exhaust chamber. Shale semi-coke is cooled by cold circulating dry distillation gas entering the lower part of the furnace, and then discharged through water seal. The latent heat of semi-coke is not fully utilized, and the thermal efficiency is not high (about 70% of the oil and gas at the outlet of the furnace is diluted by the flue gas produced by combustion in the furnace, and the calorific value is not high. Kievit retort is mature in production, and the daily processing capacity of each retort is 1000t. Its oil yield is 75% ~ 80% of that of laboratory aluminum retort (Yefimov et al.,1999; Sonne et al., 2003; Qian Jialin, 2006).
Figure 3-4 Kievit retort
Figure 3-5 Petelaud Sikes retort
5. Essex retort in Pietro, Brazil.
Petrosix retort in Petrolaud, Brazil is the largest lump shale retort in the world at present (Figure 3-5 and Figure 3-6), with a daily processing capacity of 6,000 tons of oil shale. The inner diameter of the furnace is 1 1m, the upper part is the oil shale carbonization section, and the lower part is the shale semi-coke cooling section. The hot circulating gas heated by the tubular heating furnace enters the middle of the retort furnace, and the upper oil shale is heated and retorted, thus pyrolysis produces shale oil gas and semi-coke. Oil and gas are led out from the upper part, and shale oil is recovered through the condensation recovery system. A part of shale retort gas is heated by tubular heating furnace and then circulated to the middle of retort furnace. The semi-coke in the furnace enters the lower part of the furnace, is cooled by the cold circulating gas at the bottom of the furnace, and is discharged after cooling. The technology of Petelaud Sikes furnace is mature, and the yield of shale retort oil reaches 85% ~ 90% of that of aluminum retort oil. The calorific value of dry distillation gas is high, but the fixed carbon calorific value of discharged semi-coke is not utilized (Qian Jialin et al., 2006; Martignoni et al., 2002, 2006).
Figure 3-6 Process Flow of Pete Laudsikes Factory
6. United Oil Company Rock Pump Furnace
UnionB process of United Oil Company of the United States is different from the general massive shale retort (Figure 3-7, Figure 3-8).
From bottom to top, shale is sent into the furnace by two rock pumps at the bottom of the rock pump in turn for dry distillation, and the generated shale semi-coke is about 5 10℃ and discharged from the top side. The heated hot circulating gas (540℃) enters the top of B-type furnace, and the shale is heated from top to bottom for dry distillation. The dry distillation gas is led out from the bottom of the furnace, separated by cooling oil and water, desulfurized and purified, and can be used as high temperature gas. Shale oil is exported under the furnace. The oil yield of type B furnace is close to 100% of the oil content determined by aluminum retort. The daily processing capacity of oil shale is 10000t/d, which is the largest furnace type in the world. But it closed at 1990 (barnett,1982; Callahan, 1983).
7. Gleiter furnace in Estonia
Galoter furnace in Estonia is a rotary solid heat carrier granular shale retort furnace (Figure 3-9). Hot shale ash, as a solid heat carrier, was mixed with granular shale to prepare shale oil in rotary furnace. After dry distillation, the mixture of semi-coke and shale ash is burned by air in the injection pipe, and part of the generated shale ash is recovered as a heat carrier. Each furnace processes 3000 tons of granular oil shale every day, and the oil yield is about 85% ~ 90% of that of aluminum retort. The technology is basically mature.
Figure 3-7 Rock Pump Furnace
Figure 3-8 Process Flow of Rock Pump Furnace Device
As early as 1945, the Energy Research Institute of the former Soviet Academy of Sciences, that is, the Russian Energy Research Institute (ENIN) in Moscow today, developed the Glodt furnace type. 1946 laboratory equipment was built, and gradually expanded to industrial production scale after more than half a century. Pilot and industrial test devices are mainly designed by Leningrad Design Institute of the Soviet Union and today's St. Petersburg Atomic Energy Design Institute, including UIT-25, UIT-50, UIT- 100, UIT-200, UIT-500 and UIT-3000.
Figure 3-9 Process Flow of Glodt Factory
1984, two Glot dry distillation units (UIT-3000) with a daily output of 3,000 tons of granular shale were built in Narwa Oil Shale Power Plant, Estonia, and have been running ever since. Because the scale of the device is enlarged, the process is complex, there are many equipment and rotating machinery, and the operation is not easy to master. Its operators have spent a lot of energy and material resources to constantly improve and perfect it. According to reports, the current operation situation has become normal, with an annual operation time of 6200 ~ 7200 h (designed annual operation time of 6800h). According to the operation of processing cooking oil shale, if the oil content of aluminum retort in the laboratory is 14%, it is estimated that the oil content of aluminum retort can be 12%, which is about 86%. The volumetric calorific value of dry distillation gas is 46000kJ/m3, containing 30% olefins, which can be used as chemical raw materials or household gas (Golmshtok et al., 2007).
At present, Narwa Oil Shale Power Plant cooperates with OUTOTEC from Finland to develop a new generation of Enefit technology (improved Glot furnace, Figure 3- 10). The design purpose is to strengthen waste heat recovery, reduce mechanical equipment, reduce emissions, and obtain higher oil yield and utilization rate. The design of the first factory is in progress, and construction is about to start, and it is planned to be completed in 20 12. The improved Glot furnace is called Enefit280, and the oil shale productivity of the improved retort furnace is increased from 3000t/d( 140t/h) to 6000t/d(280t/h). The original semi-coke riser combustion is changed into circulating fluidized bed combustion, and the heat generated by semi-coke combustion is used for dry distillation and the residual heat is used for power generation; Increase the waste heat recovery boiler to improve the thermal efficiency of dry distillation process; The oil and gas from dry distillation directly enters the fractionator to divide shale oil into light oil and heavy oil; The discharged hot ash is cooled in a fluidized bed to obtain heat (Weber, 2009). Enefit280 is the only technology that can maximize oil production, energy efficiency and by-product utilization.
Fig. 3-3-10 schematic diagram of enefit 280 280 caloter equipment
Advantages of Enefit280 Galoter furnace:
(1) Low environmental impact: low smoke emission; There is no residual organic matter in ash, and its content is less than 65438 0%. The oil refining process does not need water.
(2) Flexibility: It can also be used for oil shale with low calorific value and fine particles (0 ~ 25mm); All the extracted oil shale can be used without wasting oil shale; No need to use external fuel (such as natural gas, oil, electricity); It is easy to be applied to other oil shale, and there is no technical restriction on the oil content of oil shale; It is easy to control, and it is easy to modify the process if some equipment (such as drying) is not needed.
(3) High benefit: the chemical benefit of this process is 80%; Compared with Fischer, the oil production rate is103%; The thermal benefit exceeds 80%; High utilization rate (above 90%).
(4) Comprehensive utilization: the annual consumption of oil shale is 226× 104t, the annual output of shale oil is 29× 104t, the annual output of natural gas is 7500× 104m3, and the power generation is 35MW.
(5) High product quality: shale oil-low viscosity (1.2 Lito,+15℃), low sulfur content (< 0.7%) and low pour point (-15℃); High calorific value dry distillation gas; Dry distillation gas can be used for hydrogen production and power generation.
8. Canada-Australia Tasek Furnace
Taciuk furnace in Canada, also known as AlbertaTaciukProcess (ATP furnace for short), is named after WilliamTaciuk, the inventor of UMATAC Engineering Company in Canada. ATP also belongs to granular shale solid heat carrier retort. The development of ATP furnace began in 1977, and it has a development history of more than 40 years. 1986, Australia's South Pacific Petroleum Company/Central Pacific Mining Company (SPP/CPM) decided to adopt ATP technology, amplify it by about 30 times, design it for dry distillation of oil shale in Queensland, Australia, and build a Tasek furnace with a daily processing capacity of 6,000 tons of oil shale in Australia.
The device was designed by Bechtel Company in Australia and manufactured by KruppPolysius Company in Germany, with a total investment of about 280 million Australian dollars. 1997 started construction and 1999 completed trial operation. The unit has been put into trial operation for 5 ~ 6 years, and the annual operating rate is 60%(Schmidt, 2003; Macfarlane, 2003, 2004). The operation effect is not very good, and it smells bad. Local green organizations protested.
By 2004, SPP Company sold the device and related oil shale resources to Queensland Energy Company of the United States, and the device was closed in mid-2004.
The device is designed to carry out three processes of oil shale drying, dry distillation and semi-coke combustion in a horizontal cylinder rotary furnace (Figure 3- 1 1), which is ingenious in concept, but difficult to control in operation. A Tasek furnace (6000t/d) was imported from Fushun, China, and will be commissioned before the end of 20 10.
Figure 3- 1 1 tasek furnace
Generally speaking, ATP technology is immature, and the operating rate is 60%. ATP is directly amplified from the pilot test of 240t/d processing capacity to the production of 6000t/d processing capacity. Australia has now given up ATP and sold its ATP factory to American companies. The equipment is too big, with a length of 60m and a diameter of11m.
9. Lurgi-Lugers Furnace, Germany
Lurgi-Luhrgas (LG) process in Germany was jointly developed by Lurgi and Luhrgas in 1950s. This process can be used for dry distillation of granular oil shale and coal and pyrolysis of heavy oil. When the process is used for dry distillation of coal or oil shale, hot semi-coke or hot shale ash is used as a solid heat carrier, mixed with coal or shale in a twin-screw mixer and heated, and then dry distillation is completed in a moving bed reactor. The generated oil and gas and semi-coke are sent into the riser by air and burned from bottom to top, and some generated hot semi-coke or shale ash is returned to the spiral mixer for recycling (Figure 3- 12).
Figure 3- 12 Process Flow of Lurgi-Lorgas Plant
Coal dry distillation, 1957 ~ 196 1 year, a set of equipment for processing 240t bituminous coal per day was built in Doston. During 1963 ~ 1968, Yugoslavia built 1600t lignite daily treatment plant; From 1975 to 1978, a plant for processing 350 tons of bituminous coal per day was built in Batlo. 1977 ~ 1979, a set of equipment for processing 700 tons of bituminous coal per day was built in Britain. In terms of dry distillation of oil shale, the daily processing capacity of oil shale (Rammler, 1982) from the United States, Australia, Jordan and China is 12t in Herten, 8t in Essen and 24t in Frankfurt.
10. solid heat carrier retort of Dalian university of technology
1984 Dalian university of technology has developed a new dry distillation technology for granular shale and coal with solid heat carrier, which is called "large-scale engineering dry distillation technology" (fig. 3- 13). The principle flow of the new dry distillation method is similar to that of Lurgi-Rueges process (LG) in Germany, but the form and structure of key equipment are developed, designed and manufactured by Dalian University of Technology.
1984, Dalian university of technology built a new continuous test device for oil shale dry distillation with a capacity of 5 ~ 10kg/ hour, and completed the cold model test. During 1985 ~ 1986, experiments were carried out on Huadian shale, Maoming shale, Yunnan lignite, Pingzhuang lignite in Inner Mongolia and Huangxian lignite. During the period of 1990 ~ 1992, Pingzhuang Mining Bureau established a process test device for daily processing of lignite 150t, and carried out the test during the period of 1992 ~ 1993, and achieved initial success.
Fig. 3- 13 process flow of new dry distillation unit in Dalian university of technology
The principle of large-scale dry distillation process is to mix granular oil shale and shale ash as a heat carrier in a moving bed dry distillation reactor, and heat dry distillation to generate shale oil gas and semi-coke. The mixture of semi-coke and shale ash is sprayed upward by air in the heating riser (jet combustion pipe), and the semi-coke contains organic substances such as fixed carbon, which is burned to generate shale ash. Part of shale ash is separated and recovered by the rotary separator, mixed with shale in the propeller (shale pyrolysis reaction begins), enters the dry distillation reactor to heat the dry distillation shale, and the shale oil and gas is output and condensed to recover shale oil. Part of shale ash is discharged and part of it is continuously recovered (Qian, 2008; Coal Chemical Laboratory of Dalian University of Technology, 1986).
For oil shale with high calorific value and high oil content, the organic matter in shale semi-coke is burned in the riser, which is enough to heat dry distillation shale, and it is not necessary to supplement external fuel by heating the lower part of the riser. For low calorific value oil shale, the heat generated by the combustion of fixed carbon organic matter in shale semi-coke is not enough to provide dry distillation, so dry distillation gas and air need to be added to the combustion chamber at the lower end of the riser to supplement the heat.
The pilot tests of Huadian oil shale and Maoming oil shale were carried out by Dagong new method (10kg/h). The crude oil recovery of the four samples is 90% ~ 94%, the dry distillation gas production is 40 ~ 60 m3/t, and the calorific value is above 18 130kJ/m3 (Guo et al., 660 kJ/m3).
1 1.
Maoming Petroleum Company carried out two-vessel fluidized dry distillation (fluidized dry distillation of powder shale and fluidized combustion of powder semi-coke) in the 1970s, and achieved initial success (Luo, 1984,1981; Luo, 1988) (Figure 3- 14).
In recent years, China Coal Longhua Harbin Coal Chemical Company is carrying out a pilot test of fluidized dry distillation of Dalianhe oil shale in yilan county, Heilongjiang Province (processing 50t oil shale every day), which has achieved initial results. The longest continuous operation is 192h, and the oil yield reaches 80% of aluminum dry distillation (Wang et al., 2009).
The advantage of this fluidized carbonization system is that it can make full use of oil shale resources, that is, oil shale is ground into oil shale powder particles less than 3 mm, and then treated in a carbonization furnace; Products include shale oil, natural gas and ash (which can be used as raw materials for cement, ceramsite and bricklaying). The production cost of shale oil is about 2,000 yuan /t, and the cost of deep processing (hydrogenation to gasoline and diesel) is 2,700 yuan/t. craftworld, China Coal Longhua, has a large processing capacity of 2,000 t/furnace. Longhua process of China Coal is superior to Fushun furnace. Fushun furnace was developed by the Japanese in 1929, with only 100t/ furnace; Moreover, Fushun furnace can only handle large particles, but not small particles (particles < < 12mm).
Comparatively speaking, the pilot work of China Coal Longhua is much deeper than that of PetroChina Daqing. The former has higher oil yield and higher magnification than the latter. However, the former has more fluidized dust than the latter, which is difficult to treat.
Fig. 3- 14 process flow of Maoming fluidized dry distillation unit