To increase purified gas production and reduce the comprehensive energy consumption of high-sulfur natural gas sweetening unit,a process simulation model was established by using ProMax based on the field operation da...To increase purified gas production and reduce the comprehensive energy consumption of high-sulfur natural gas sweetening unit,a process simulation model was established by using ProMax based on the field operation data in the Sinopec Puguang Natural Gas Purification Plant.Then,sensitivity analysis and optimization study were carried out on the main operating parameters,including circulation rates,the concen-trations and the inlet temperatures of primary and secondary absorption towers of MDEA(methyldiethanolamine)solutions.Furthermore,the effects of reduction of the feed gas load and pressure and increasement of H_(2)S content on the quality and yield rates of purified gas were analyzed under the optimized operating conditions with the actual field situations.And the following research results were obtained.First,the absorption selectivity of MDEA solutions can be improved by decreasing the circulation rates,concentrations and inlet temperatures of MDEA solutions,which is favorable for the increase of the yield rates of purified gas.Specifically,the circulation rate of MDEA solution is the main factor influencing the comprehensive energy consumption of a high-sulfur natural gas sweetening unit.Second,when the flow rate,pressure and H 2S content of feed gas fluctuate,the purification requirements can be satisfied under the optimized operating conditions.Third,energy con-servation under low flow rates of feed gas can be achieved by reducing the flow rates of regenerated steam and adjusting the position of MDEA solutions entering the secondary absorption tower.Fourth,as H_(2)S content is increased by 1%,it is necessary to increase the circulation rate of MDEA solution by about 20×10^(3)kg/h.Fifth,after parameter optimization,the yield rate of purified gas is increased by 0.5%and the comprehensive energy consumption is reduced by 19.1%under the operating condition of full load.展开更多
Aerated irrigation has been proven to increase crop production and quality, but studies on its environmental impacts are sparse. The effects of aeration and irrigation regimes on soil CO2 and N2O emissions in two cons...Aerated irrigation has been proven to increase crop production and quality, but studies on its environmental impacts are sparse. The effects of aeration and irrigation regimes on soil CO2 and N2O emissions in two consecutive greenhouse tomato rotation cycles in Northwest China were studied via the static closed chamber and gas chromatography technique. Four treatments, aerated deficit irrigation（AI1）, non-aerated deficit irrigation（CK1）, aerated full irrigation（AI2） and non-aerated full irrigation（CK2）, were performed. The results showed that the tomato yield under aeration of each irrigation regime increased by 18.8% on average compared to non-aeration, and the difference was significant under full irrigation（P〈0.05）. Full irrigation significantly increased the tomato yield by 23.9% on average in comparison to deficit irrigation. Moreover, aeration increased the cumulative CO2 emissions compared to non-aeration, and treatment effects were significant in the autumn-winter season（P〈0.05）. A slight increase of CO2 emissions in the two seasons was observed under full irrigation（P〉0.05）. There was no significant difference between aeration and non-aeration in soil N2O emissions in the spring-summer season, whereas aeration enhanced N2O emissions significantly in the autumn-winter season. Furthermore, full irrigation over the two seasons greatly increased soil N2O emissions compared to the deficit irrigation treatment（P〈0.05）. Correlation analysis indicated that soil temperature was the primary factor influencing CO2 fluxes. Soil temperature, soil moisture and NO3^- were the primary factors influencing N2O fluxes. Irrigation coupled with particular soil aeration practices may allow for a balance between crop production yield and greenhouse gas mitigation in greenhouse vegetable fields.展开更多
This paper describes an experimental investigation of pyrolysis of woody biomass mixture. The mixture consists of oak, beech, fir, cherry, walnut and linden wood chips with equal mass fractions. During the experiment,...This paper describes an experimental investigation of pyrolysis of woody biomass mixture. The mixture consists of oak, beech, fir, cherry, walnut and linden wood chips with equal mass fractions. During the experiment, the sample mass inside the reactor was 10 g with a particle diameter of 5-10 mm. The sample in the reactor was heated in the temperature range of 24-650℃. Average sample heating rates in the reactor were 21, 30 and 54 ℃/min. The sample mass before, during and after pyrolysis was determined using a digital scale. Experimental results of the sample mass change indicate that the highest yield of pyrolytic gas was achieved at the temperature slightly above 650℃ and ranged from 77 to 85%, while char yield ranged from 15 to 23%. Heating rate has sig- nificant influence on the pyrolytic gas and char yields. It was determined that higher pyrolysis temperatures and heating rates induce higher yields of pyrolytic gas, while the char mass reduces. Condensation of pyrolytic gas at the end of the pyrolysis process at 650℃ produced 2.4-2.72 g of liquid phase. The results obtained represent a starting basis for determining material and heat balance of pyrolysis process as well as woody biomass pyrolysis equipment.展开更多
基金Project supported by the National Science and Technology Major Project“Technologies for the Safe and Efficient Operation of Gathering and Purification System in High-Sulfur Gas Fields”(No.2016ZX05017-004).
文摘To increase purified gas production and reduce the comprehensive energy consumption of high-sulfur natural gas sweetening unit,a process simulation model was established by using ProMax based on the field operation data in the Sinopec Puguang Natural Gas Purification Plant.Then,sensitivity analysis and optimization study were carried out on the main operating parameters,including circulation rates,the concen-trations and the inlet temperatures of primary and secondary absorption towers of MDEA(methyldiethanolamine)solutions.Furthermore,the effects of reduction of the feed gas load and pressure and increasement of H_(2)S content on the quality and yield rates of purified gas were analyzed under the optimized operating conditions with the actual field situations.And the following research results were obtained.First,the absorption selectivity of MDEA solutions can be improved by decreasing the circulation rates,concentrations and inlet temperatures of MDEA solutions,which is favorable for the increase of the yield rates of purified gas.Specifically,the circulation rate of MDEA solution is the main factor influencing the comprehensive energy consumption of a high-sulfur natural gas sweetening unit.Second,when the flow rate,pressure and H 2S content of feed gas fluctuate,the purification requirements can be satisfied under the optimized operating conditions.Third,energy con-servation under low flow rates of feed gas can be achieved by reducing the flow rates of regenerated steam and adjusting the position of MDEA solutions entering the secondary absorption tower.Fourth,as H_(2)S content is increased by 1%,it is necessary to increase the circulation rate of MDEA solution by about 20×10^(3)kg/h.Fifth,after parameter optimization,the yield rate of purified gas is increased by 0.5%and the comprehensive energy consumption is reduced by 19.1%under the operating condition of full load.
基金supported by the National Natural Science Foundation of China (51309192)the National Key Research and Development Program of China (2016YFC0400201)the Fundamental Research Funds for the Central Universities, China (Z109021510)
文摘Aerated irrigation has been proven to increase crop production and quality, but studies on its environmental impacts are sparse. The effects of aeration and irrigation regimes on soil CO2 and N2O emissions in two consecutive greenhouse tomato rotation cycles in Northwest China were studied via the static closed chamber and gas chromatography technique. Four treatments, aerated deficit irrigation（AI1）, non-aerated deficit irrigation（CK1）, aerated full irrigation（AI2） and non-aerated full irrigation（CK2）, were performed. The results showed that the tomato yield under aeration of each irrigation regime increased by 18.8% on average compared to non-aeration, and the difference was significant under full irrigation（P〈0.05）. Full irrigation significantly increased the tomato yield by 23.9% on average in comparison to deficit irrigation. Moreover, aeration increased the cumulative CO2 emissions compared to non-aeration, and treatment effects were significant in the autumn-winter season（P〈0.05）. A slight increase of CO2 emissions in the two seasons was observed under full irrigation（P〉0.05）. There was no significant difference between aeration and non-aeration in soil N2O emissions in the spring-summer season, whereas aeration enhanced N2O emissions significantly in the autumn-winter season. Furthermore, full irrigation over the two seasons greatly increased soil N2O emissions compared to the deficit irrigation treatment（P〈0.05）. Correlation analysis indicated that soil temperature was the primary factor influencing CO2 fluxes. Soil temperature, soil moisture and NO3^- were the primary factors influencing N2O fluxes. Irrigation coupled with particular soil aeration practices may allow for a balance between crop production yield and greenhouse gas mitigation in greenhouse vegetable fields.
基金Partially financed by the Ministry of Education,Science and Technological Development of the Republic of Serbia
文摘This paper describes an experimental investigation of pyrolysis of woody biomass mixture. The mixture consists of oak, beech, fir, cherry, walnut and linden wood chips with equal mass fractions. During the experiment, the sample mass inside the reactor was 10 g with a particle diameter of 5-10 mm. The sample in the reactor was heated in the temperature range of 24-650℃. Average sample heating rates in the reactor were 21, 30 and 54 ℃/min. The sample mass before, during and after pyrolysis was determined using a digital scale. Experimental results of the sample mass change indicate that the highest yield of pyrolytic gas was achieved at the temperature slightly above 650℃ and ranged from 77 to 85%, while char yield ranged from 15 to 23%. Heating rate has sig- nificant influence on the pyrolytic gas and char yields. It was determined that higher pyrolysis temperatures and heating rates induce higher yields of pyrolytic gas, while the char mass reduces. Condensation of pyrolytic gas at the end of the pyrolysis process at 650℃ produced 2.4-2.72 g of liquid phase. The results obtained represent a starting basis for determining material and heat balance of pyrolysis process as well as woody biomass pyrolysis equipment.
