Over the past 80 years,dozens of underground coal gasification(UCG)mine field tests have been carried out around the world.However,in the early days,only a small number of shallow UCG projects in the former Soviet Uni...Over the past 80 years,dozens of underground coal gasification(UCG)mine field tests have been carried out around the world.However,in the early days,only a small number of shallow UCG projects in the former Soviet Union achieved commercialised production.In this century,a few pilot projects in Australia also achieved short-term small-scale commercialised production using modern UCG technology.However,the commercialisation of UCG,especially medium-deep UCG projects with good development prospects but difficult underground engineering conditions,has not progressed smoothly around the world.Considering investment economy,a single gasifier must realise a high daily output and accumulated output,as well as hold a long gasification tunnel to control a large number of coal resources.However,a long gasification tunnel can easily be affected by blockages and failure,for which the remedial solutions are difficult and expensive,which greatly restricts the investment economy.The design of the underground gasifier determines the success or failure of UCG projects,and it also requires the related petroleum engineering technology.Combining the advantages of the linear horizontal well(L-CRIP)and parallel horizontal well(P-CRIP),this paper proposes a new design scheme for an“inclined ladder”underground gasifier.That is to say,the combination of the main shaft of paired P-CRIP and multiple branch horizontal well gasification tunnels is adopted to realise the control of a large number of coal resources in a single gasifier.The completion of the main shaft by well cementation is beneficial for maintaining the integrity of the main shaft and the stability of the main structure.The branch horizontal well is used as the gasification tunnel,but the length and number of retracting injection points are limited,effectively reducing the probability of blockage or failure.The branch horizontal well spacing can be adjusted flexibly to avoid minor faults and large cracks,which is conducive to increasing the resource utilisation rate.In add展开更多
Rural area in Indonesia of which electrification ratio is still low has a strong demand for off-grid electric power supply. On the other hand, Indonesia is a leading natural rubber production country and these rubber ...Rural area in Indonesia of which electrification ratio is still low has a strong demand for off-grid electric power supply. On the other hand, Indonesia is a leading natural rubber production country and these rubber wood trees are cultivated in vast plantation farms. A rubber wood tree is woody biomass resource which can be stably supplied because a lot of trees aged more than 25 years are logged and nursery trees are planted constantly. Woody biomass is burned directly as solid fuel and the generated thermal energy can be applied only for room heating or cooking. Otherwise, direct conversion of biomass to electric energy requires a large scale equipment such as a boiler and a steam turbine, whereas gasified woody biomass can be easily handled and can have wide application. A closed gasifier chamber which was kept vacuum and fulfilled with gas yield during gasification was recently developed by the authors for indirect gasification. It was confirmed that generated gas by the gasifier is clean and can be directly used to drive an engine generator to supply electricity. In this study, planer dust of rubber wood is used as gasification feedstock for indirect gasifying in the closed gasifier chamber, and effects of heating temperature and moisture content on gasification performance are discussed to examine characteristics of the closed gasifier chamber in details.展开更多
文摘Over the past 80 years,dozens of underground coal gasification(UCG)mine field tests have been carried out around the world.However,in the early days,only a small number of shallow UCG projects in the former Soviet Union achieved commercialised production.In this century,a few pilot projects in Australia also achieved short-term small-scale commercialised production using modern UCG technology.However,the commercialisation of UCG,especially medium-deep UCG projects with good development prospects but difficult underground engineering conditions,has not progressed smoothly around the world.Considering investment economy,a single gasifier must realise a high daily output and accumulated output,as well as hold a long gasification tunnel to control a large number of coal resources.However,a long gasification tunnel can easily be affected by blockages and failure,for which the remedial solutions are difficult and expensive,which greatly restricts the investment economy.The design of the underground gasifier determines the success or failure of UCG projects,and it also requires the related petroleum engineering technology.Combining the advantages of the linear horizontal well(L-CRIP)and parallel horizontal well(P-CRIP),this paper proposes a new design scheme for an“inclined ladder”underground gasifier.That is to say,the combination of the main shaft of paired P-CRIP and multiple branch horizontal well gasification tunnels is adopted to realise the control of a large number of coal resources in a single gasifier.The completion of the main shaft by well cementation is beneficial for maintaining the integrity of the main shaft and the stability of the main structure.The branch horizontal well is used as the gasification tunnel,but the length and number of retracting injection points are limited,effectively reducing the probability of blockage or failure.The branch horizontal well spacing can be adjusted flexibly to avoid minor faults and large cracks,which is conducive to increasing the resource utilisation rate.In add
文摘Rural area in Indonesia of which electrification ratio is still low has a strong demand for off-grid electric power supply. On the other hand, Indonesia is a leading natural rubber production country and these rubber wood trees are cultivated in vast plantation farms. A rubber wood tree is woody biomass resource which can be stably supplied because a lot of trees aged more than 25 years are logged and nursery trees are planted constantly. Woody biomass is burned directly as solid fuel and the generated thermal energy can be applied only for room heating or cooking. Otherwise, direct conversion of biomass to electric energy requires a large scale equipment such as a boiler and a steam turbine, whereas gasified woody biomass can be easily handled and can have wide application. A closed gasifier chamber which was kept vacuum and fulfilled with gas yield during gasification was recently developed by the authors for indirect gasification. It was confirmed that generated gas by the gasifier is clean and can be directly used to drive an engine generator to supply electricity. In this study, planer dust of rubber wood is used as gasification feedstock for indirect gasifying in the closed gasifier chamber, and effects of heating temperature and moisture content on gasification performance are discussed to examine characteristics of the closed gasifier chamber in details.
