Based on regional CBM geological characteristics and drainage data of three typical Coalbed Methane(CBM) wells in the southern Qinshui Basin,history matching,productivity prediction and factor analysis of gas producti...Based on regional CBM geological characteristics and drainage data of three typical Coalbed Methane(CBM) wells in the southern Qinshui Basin,history matching,productivity prediction and factor analysis of gas production control are conducted by using COMET3 reservoir modeling software.The results show that in the next 20 years,the cumulative and average daily gas production of the QN01 well are expected to be 800×104 m3 and 1141.1 m3/d,for the QN02 well 878×104 m3 and 1202.7 m3/d and 97.5×104 m3 and 133.55 m3/d for the QN03 well.Gas content and reservoir pressure are the key factors controlling gas production in the area;coal thickness,permeability and porosity are less important;the Langmuir volume,Langmuir pressure and adsorption time have relatively small effect.In the process of CBM recovery,the material source and driving force are the key features affecting gas productivity,while the permeation process is relatively important and the desorption process has some impact on gas recovery.展开更多
It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the pro...It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the productivity of CBM. With the test report and the related geological parameters of a single well, methods of combining the productivity data and typical production curves were used to analyze different geological factors and how to influence the capacity of a single layer. Then, the paper proposed a new understanding about capacity characteristics of the study area and geological control factors： First, the Shanxi formation production capacity characteristics was divided into two-stages, showing signs of gas and gas break- through for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were bet- ter than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well pro- duction. Finally, comprehensive analysis concluded that the ratio of critical desorption pressure to reservoir pressure has greater influence on the production of vertical CBM wells. Besides, the potential of gas production capacity has greater impact at stage of showing gas signs; the coal reservoir pressure and gas production capacity have greater impact at stage of gas breakthrough for 100 days. Thus, to seek the coal bed methane with high ratio of critical desorption pressure to reservoir pressure and high yield of gas will be important guarantee to the success of the coal bed methane exploration and development.展开更多
Different VSA （Vacuum Swing Adsorption） cycles and process schemes have been evaluated to find suitable process configurations for effectively separating C02 from flue gases from different industrial sectors. The cy...Different VSA （Vacuum Swing Adsorption） cycles and process schemes have been evaluated to find suitable process configurations for effectively separating C02 from flue gases from different industrial sectors. The cycles were studied using an adsorption simulator developed in our research group, which has been suc- cessfully used to predict experimental results over severa~ years. Commercial zeolite APGIlI and granular ac- tivated carbon were used as the adsorbents. Three-bed VSA cycles with- and without-product purge and 2- stage VSA systems have been investigated. It was found that for a feed gas containing 15% CO2 （representing flue gas from power plants）, high CO2 purities and recoveries could be obtained using a three-bed zeolite APGII1 VSA unit for one stage capture, but with more stringent conditions such as deeper vacuum pressures of 1-3 kPa. 2-stage VSA process operated in series allowed us to use simple process steps and operate at more realistic vacuum pressures. With a vacuum pressure of 10 kPa, final C02 purity of 95.3% with a recov- ery of 98.2% were obtained at specific power consumption of 0.55 MJ. （kg CO2） 1 from feed gas containing 15% C02. These numbers compare very well with those obtained from a single stage process operating at I kPa vacuum pressure. The feed CO2 concentration was very influential in determining the desorption pressure necessary to achieve high separation efficiency. For feed gases containing 〉30% CO2, a singlestage VSA capture process operating at moderate vacuum pressure and without a product purge, can achieve very high product purities and recoveries.展开更多
An anaerobic digestion unit for producing biogas from cow dung in the rural communities was designed, fabricated and tested for performance, durability and throughput. The major components of the digester included the...An anaerobic digestion unit for producing biogas from cow dung in the rural communities was designed, fabricated and tested for performance, durability and throughput. The major components of the digester included the substrate holding tank, tank cover, agitator, debris collector, inlet and outlet pipes, gas reception tank, hose and heat source. The digester is a vertical cylindrical tank with an inlet pipe for the introduction of substrate and an outlet pipe to collect the digested substrate. An agitator is incorporated inside the digester to break scum on the substrate and create uniform temperature profile in the digester while a pressure gauge was fitted to the gas outlet valve to measure the gas pressure in the tank. The agitator shaft is extended outside to be driven by an electric motor through belt and pulley system. The criteria considered in the design of the digester included air tightness of the system, mesophilic and thermophilic temperature, nature and type of substrate used, substrate retention period, number of crank turns per minute and volumetric capacity of the digestion tank. Other considerations included the desire to make the digestion tank and gas reception tank of galvanized steel to ensure good quality of the product and the need for a strong structural support to ensure structural stability of the system. After construction and assembly, the biogas digestion unit was tested with 40 kg of cow dung diluted with 80 kg of water and subjected to a retention period to make a substrate （slurry） of 10 % total solid （TS）. Daily gas yield was determined; gas pressure in the tank was measured by the pressure gauge, while the ambient temperature was taken at five hours interval. Results showed that a cumulative gas yield of 0.415 litres after 22 d retention period at average substrate temperature and pH of 29 ℃ and 6.2, respectively. The digester has a substrate holding capacity of 330.8 litres and a production cost of $375 with all the construction materials being available locally.展开更多
基金the National Basic Research Program of China (No.2009 CB219605)the Key Program of the National Natural Science Foundation of China (No.4073042)the Key Program of the National Science and Technology of China (No.2008ZX05034-04)
文摘Based on regional CBM geological characteristics and drainage data of three typical Coalbed Methane(CBM) wells in the southern Qinshui Basin,history matching,productivity prediction and factor analysis of gas production control are conducted by using COMET3 reservoir modeling software.The results show that in the next 20 years,the cumulative and average daily gas production of the QN01 well are expected to be 800×104 m3 and 1141.1 m3/d,for the QN02 well 878×104 m3 and 1202.7 m3/d and 97.5×104 m3 and 133.55 m3/d for the QN03 well.Gas content and reservoir pressure are the key factors controlling gas production in the area;coal thickness,permeability and porosity are less important;the Langmuir volume,Langmuir pressure and adsorption time have relatively small effect.In the process of CBM recovery,the material source and driving force are the key features affecting gas productivity,while the permeation process is relatively important and the desorption process has some impact on gas recovery.
文摘It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the productivity of CBM. With the test report and the related geological parameters of a single well, methods of combining the productivity data and typical production curves were used to analyze different geological factors and how to influence the capacity of a single layer. Then, the paper proposed a new understanding about capacity characteristics of the study area and geological control factors： First, the Shanxi formation production capacity characteristics was divided into two-stages, showing signs of gas and gas break- through for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were bet- ter than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well pro- duction. Finally, comprehensive analysis concluded that the ratio of critical desorption pressure to reservoir pressure has greater influence on the production of vertical CBM wells. Besides, the potential of gas production capacity has greater impact at stage of showing gas signs; the coal reservoir pressure and gas production capacity have greater impact at stage of gas breakthrough for 100 days. Thus, to seek the coal bed methane with high ratio of critical desorption pressure to reservoir pressure and high yield of gas will be important guarantee to the success of the coal bed methane exploration and development.
基金Supported by the Corporate Research Centre for Greenhouse Gas Technology Foundation in Australiathe National Natural Science Foundation of China(51074205)
文摘Different VSA （Vacuum Swing Adsorption） cycles and process schemes have been evaluated to find suitable process configurations for effectively separating C02 from flue gases from different industrial sectors. The cycles were studied using an adsorption simulator developed in our research group, which has been suc- cessfully used to predict experimental results over severa~ years. Commercial zeolite APGIlI and granular ac- tivated carbon were used as the adsorbents. Three-bed VSA cycles with- and without-product purge and 2- stage VSA systems have been investigated. It was found that for a feed gas containing 15% CO2 （representing flue gas from power plants）, high CO2 purities and recoveries could be obtained using a three-bed zeolite APGII1 VSA unit for one stage capture, but with more stringent conditions such as deeper vacuum pressures of 1-3 kPa. 2-stage VSA process operated in series allowed us to use simple process steps and operate at more realistic vacuum pressures. With a vacuum pressure of 10 kPa, final C02 purity of 95.3% with a recov- ery of 98.2% were obtained at specific power consumption of 0.55 MJ. （kg CO2） 1 from feed gas containing 15% C02. These numbers compare very well with those obtained from a single stage process operating at I kPa vacuum pressure. The feed CO2 concentration was very influential in determining the desorption pressure necessary to achieve high separation efficiency. For feed gases containing 〉30% CO2, a singlestage VSA capture process operating at moderate vacuum pressure and without a product purge, can achieve very high product purities and recoveries.
文摘An anaerobic digestion unit for producing biogas from cow dung in the rural communities was designed, fabricated and tested for performance, durability and throughput. The major components of the digester included the substrate holding tank, tank cover, agitator, debris collector, inlet and outlet pipes, gas reception tank, hose and heat source. The digester is a vertical cylindrical tank with an inlet pipe for the introduction of substrate and an outlet pipe to collect the digested substrate. An agitator is incorporated inside the digester to break scum on the substrate and create uniform temperature profile in the digester while a pressure gauge was fitted to the gas outlet valve to measure the gas pressure in the tank. The agitator shaft is extended outside to be driven by an electric motor through belt and pulley system. The criteria considered in the design of the digester included air tightness of the system, mesophilic and thermophilic temperature, nature and type of substrate used, substrate retention period, number of crank turns per minute and volumetric capacity of the digestion tank. Other considerations included the desire to make the digestion tank and gas reception tank of galvanized steel to ensure good quality of the product and the need for a strong structural support to ensure structural stability of the system. After construction and assembly, the biogas digestion unit was tested with 40 kg of cow dung diluted with 80 kg of water and subjected to a retention period to make a substrate （slurry） of 10 % total solid （TS）. Daily gas yield was determined; gas pressure in the tank was measured by the pressure gauge, while the ambient temperature was taken at five hours interval. Results showed that a cumulative gas yield of 0.415 litres after 22 d retention period at average substrate temperature and pH of 29 ℃ and 6.2, respectively. The digester has a substrate holding capacity of 330.8 litres and a production cost of $375 with all the construction materials being available locally.
