Gas Allocation Research Articles

Further insights into the allocation of greenhouse gas emissions to shipments in road freight transportation: The pollution routing game

Abstract At present, there is no globally accepted standard for the allocation of greenhouse gas (GHG) emissions to shipments in road freight transportation. The only official international standard for emission calculation of transport operations is the European Norm EN-16258. However, even this norm still allows choosing from several alternative emission allocation schemes. This research aims to harmonize the process of GHG declarations for supply chains by identifying among all allocation units specified by EN-16258 the one that describes a shipment's contribution to GHG emissions best. For this purpose, concepts of the cooperative game theory are used. First, we develop three transport scenarios that allow studying a shipment's effect on GHG: a vehicle routing problem, a network flow model, and a mixed scenario. Our approach extends previous research projects because we take into account that shipment characteristics in terms of origin, destination, weight, and volume consume transport capacities to different degrees, impact the routing of the commercial vehicles and, thus, determine GHG. Second, we present the results of a computational study that bases on the introduced transport scenarios and that compares the allocation vectors resulting from the EN-16258 allocation rules with the Shapley value, which serves as a benchmark for a shipment's contribution to GHG. Furthermore, we show how often the EN-16258 allocation principles are in line with a set of game theoretical fairness criteria. The results indicate that the allocation unit ‘distance’ is the closest to the game theory benchmark and most often in line with game theoretical fairness criteria.

Optimal design of distributed energy systems for industrial parks under gas shortage based on augmented ε-constraint method

Natural gas distributed energy systems have developed rapidly owing to their high efficiency, low environmental impact, high energy supply reliability, and good economic returns. As the main users of natural gas distributed energy, industrial parks account for 67.7% of the total installed capacity of the industry. Therefore, disrupted gas supply to industrial parks during gas shortage periods results in decreased production and consequently huge economic losses. This study addresses this issue by attempting to develop an optimized design for distributed energy systems and natural gas allocation in multiple industrial parks under gas shortage conditions. A multi-objective mathematical programming (MOMP) model is established to minimize the total construction investment and operation costs of each industrial park considering emission, energy balance and other technical constraints. Using the augmented ε-constraint method, optimal configurations of distributed energy systems, operation strategy, and economic and emission performance of each industrial park are determined. The distributed energy system design for three industrial parks in Jinan, China, is taken as an example to verify the model. Compared with the non-cooperation case, the annual total cost of full-cooperation can be reduced by 8.29%, and the annual total carbon emission of full-cooperation can be reduced by 427.55 t. Additionally, sensitivity analyses of energy price and total input natural gas are conducted to provide further insights into the optimization of distributed energy system for each industrial park. The results show that electricity price has the strongest impact on the economic performance of the industrial parks, followed by natural gas price and biomass price, but natural gas price does not affect the gas allocation ratio. Moreover, when the total input natural gas is increased by 10–90%, the total cost can be reduced by 0.69%–7.83%.

An improved optimization method in gas allocation for continuous flow gas-lift system

The primary objective in the continuous flow gas-lift operations is to inject an optimal gas volume for a group of wells to maximize oil production. Due to the gas supply constraint in an oilfield, optimization of gas injection plays an important role in achieving this goal. In this work, for modeling of gas-lift operation, the potential application of an Artificial Neural Network (ANN) using Bayesian Regularization (BR) is investigated and the results are compared with Levenberg–Marquardt (LM) back-propagation training algorithm. For the optimization, Teaching–Learning-Based Optimization (TLBO) algorithm is applied to simultaneously solve the well-rate and gas-lift allocation problems under the injection capacity constraint. The efficiency of the TLBO is investigated based on (a) convergence rate and (b) the best solution, by comparing its performance with Genetic Algorithm (GA). Extensive published data are used in model development and comparison. The proposed prediction and optimization model is tested in a gas-lift system for a given period of reservoir life. The prediction accuracy produced by the BRNN and the LMNN were 99.9% and 99.5% respectively. Results indicate that the two models have good predictive capability. Also, results show that the BR model appears more robust and efficient than the LM model and for the optimization algorithms, TBLO outperforms GA in the gas allocation mapping for continuous gas-lift system. The simulation results demonstrate the effectiveness of the proposed model on continuous flow gas-lift operations.

Further Insights into the Allocation of Greenhouse Gas Emissions to Shipments in Road Freight Transportation: The Pollution Routing Game

At present, there is no globally accepted standard for the allocation of greenhouse gas (GHG) emissions to shipments in road freight transportation. The only official international standard for emission calculation of transport operations is the European Norm EN-16258. However, even this norm still allows choosing from several alternative emission allocation schemes. This research aims to harmonize the process of GHG declarations for supply chains by identifying among all allocation units specified by EN-16258 the one that describes a shipment's contribution to GHG emissions best. For this purpose, concepts of the cooperative game theory are used. First, we develop three transport scenarios that allow studying a shipment's effect on GHG: a vehicle routing problem, a network flow model, and a mixed scenario. Our approach extends previous research projects because we take into account that shipment characteristics in terms of origin, destination, weight, and volume consume transport capacities to different degrees, impact the routing of the commercial vehicles and, thus, determine GHG. Second, we present the results of a computational study that bases on the introduced transport scenarios and that compares the allocation vectors resulting from the EN-16258 allocation rules with the Shapley value, which serves as a benchmark for a shipment's contribution to GHG. Furthermore, we show how often the EN-16258 allocation principles are in line with a set of game theoretical fairness criteria. The results indicate that the allocation unit ‘distance’ is the closest to the game theory benchmark and most often in line with game theoretical fairness criteria.

Effect of biologicall active preparations on growth, resistance, and chlorophyll content of Garden cosmos in South Yakutia

We represented the effects of biologically active preparations (BAP), which were extracted from South Yakutia plants by the author's technology. The substances were tested in the open ground in Neryungri town (South Yakutia) on Cosmos bipinnatus Cav. The proposed method of obtaining BAS is aims to increase content in plant raw materials of physiologically active compounds through processes of gradual fermentation without rapid gas allocation. This effect was achieved through periodic short-term heat extraction system to 70 °С (Patent RU 2607013). Some four substances were obtained and applied in our research communities. is the mix of Melilotus officinalis L. and Melilotus albus Medikus.; 2 - the mix of Oberna behen L., Sanguisorba officinalis L. , Plantago major L.; 3 - the mix of Ribes fragrans Pall., Ledum palustre L., Artemisia lagocefala (Bess.) DC; - the mix of meadow’s plants ( Chamaenerion angustifolium (L.) Scop., Trifolium pratense L., Tanacetum vulgare L., Rubus idaeus L., Artemisia vulgaris L., Artemisia integrifolia L., Equisetum arvense L., Galium album Mill.). We got the working solutions from these compositions by method of decimal dilutions and dynamization. We applied BAS solutions for the of Cosmos bipinnatus seeds pre-soaking. The application of compositions 1-4 contributed to the increase in number of plants on plots at 10-24% compared with the control variant. Most significant growth stimulating activity was observed in the case of using. For this variant noted the greatest plant height, maximum number of leaves on 1 plant, the maximum value of the indicators of the leaf surface of the plant and Leaf Area of all plants in 1 plot. Analysis of the photosynthetic apparatus properties shows significant increase chlorophylls a, b, and carotenoids in the tissues of treated plants, excepting the variant with application of 3. The maximum number of pigments ware observed in plants treated by Compositions 4 and 2. Under the influence of the studied treatments of BAP increased the resistance of plant tissues to the frost. The destructions after autumn frost in the control plants ware in averaged 46.2 %; but in plants, treated with preparations 2 and Composition 3, was destructed only 32-36% tissues from the whole plant. The smallest damage, at the level of 10.5%, registered for plants, which treated with 4. The reason for the increase of plant stability, in our opinion, is in a high concentration of sugars in cellular juice and increase of content of yellow pigments in the tissues.

Dynamic allocation of surplus by-product gas in a steel plant by dynamic programming with a reduced state space algorithm

ABSTRACTSurplus by-product gas (SBPG) in a steel plant is the difference between gas production and consumption. Dynamic programming (DP) has been observed to be a useful method for SBPG dynamic allocation. However, in the SBPG allocation problem, standard dynamic programming (SDP) usually suffers from dimensionality. In this study, a novel dynamic programming method with a reduced state space algorithm (RSS-DP) is proposed. By decomposing the amount of SBPG into the reference and subsequent allocation, RSS-DP reduces the state space of the SDP model significantly such that the computation time is significantly reduced. An example of a five-boiler allocation of SBPG and a real-world online allocation of SBPG in these five boilers of a steel plant are implemented to exhibit the effectiveness of the proposed algorithm. In both cases, the solutions obtained using the proposed method are better than those obtained by traditional methods, in both computation time and energy benefit.

Optimization methods for petroleum fields development and production systems: a review

In this review, we survey the widespread use of numerical optimization or mathematical programming approaches to develop and produce petroleum fields for design and operations; lift gas and rate allocation; and reservoir development, planning, and management. Early applications adopted linear programming alongside heuristics. With continuous advancements in computing speed and algorithms, we have been able to formulate more complex and meaningful models including nonlinear programs and mixed-integer linear and nonlinear programs. Various formulations and solution strategies have been used including continuous and discrete optimization, stochastic programming to handle uncertainty, and metaheuristics such as genetic algorithms to increase solution quality while reducing computational load.

Optimal allocation of surplus gas and suitable capacity for buffer users in steel plant

Byproduct gases are an important secondary energy source in the iron and steel industry. A novel mathematical programming model was established in this paper to study the optimal allocation of surplus gas in buffer users in the byproduct gas system, on the basis of which a new method for calculating the suitable capacities of gasholders and boilers was also proposed. The validity and practicability of the model and the design method were tested in an iron and steel enterprise. The results show that gas emissions were controlled, boiler efficiency was improved, and surplus gas-related power generation was increased by approximately 5×104kWh in each hour compared with the actual data from the iron and steel enterprise. Finally, fitting curves of the relationship between the designed fuel load of the boiler and the capacity of the gasholder were obtained. Scientific guidance is thus provided for the improvement of buffer users in steel plants in the future.

Interactive effects of waterlogging and atmospheric CO2 concentration on gas exchange, growth and functional traits of Australian riparian tree seedlings

AbstractThe ability to survive and thrive in repeatedly waterlogged soils is characteristic of plants adapted to riparian habitats. Rising atmospheric CO2 has the potential to fundamentally alter plant responses to waterlogging by altering gas exchange rates and stoichiometry, modifying growth, and shifting resource‐economic trade‐offs to favor different ecological strategies. While plant responses to waterlogging and elevated CO2 individually are relatively well characterized, few studies have asked how the effects of waterlogging might be mediated by atmospheric CO2 concentration.We investigated interactive effects of elevated (550 ppm) atmospheric CO2 and waterlogging on gas exchange, biomass accumulation and allocation, and functional traits for juveniles of three woody riparian tree species. In particular, we were interested in whether elevated CO2 mitigated growth reduction under waterlogging, and whether this response was sustained following a refractory “recovery” period during which soils were re‐aerated.We found species‐specific effects of atmospheric CO2 concentration and waterlogging status on growth, gas exchange, and functional traits between species, and no evidence for a general effect of elevated CO2 in mediating plant responses to flooding. For one specie, Casuarina cunninghamiana, elevated CO2 substantially increased growth, but this effect was entirely removed by waterlogging, and there was no recovery following a refractory period.Differential responses to combined waterlogging and elevated CO2 among species may result in compositional changes to riparian plant communities and associated changes in ecosystem functioning.

On the systematic allocation of natural gas under footprint constraints in industrial clusters

On the systematic allocation of natural gas under footprint constraints in industrial clusters

Estimation of natural gas optimum allocation to consuming sectors in year 2025 in Iran

ABSTRACTDue to a large number of rich natural gas reserves in Iran, and considering the acceptable income from the exports of oil products, the consumption of gas instead of oil products in different consuming sectors seems to be rational. Therefore, in this article, the allocation of natural gas to different sectors such as residential, industries, power plants, transportation, reinjection to oil wells, export, and so forth is estimated based on the three scenarios using a linear programming method for the year 2025 in Iran. The results indicate that if there is no planned consumption management, the allocation of gas in future years will certainly have deficiencies in some sectors in Iran. Consequently, the feasible limit for unit replacement revenue of injection to oil wells is also calculated by sensitivity analysis on the coefficients of linear programming.

Fast-growing Acer rubrum differs from slow-growing Quercus alba in leaf, xylem and hydraulic trait coordination responses to simulated acid rain.

We investigated the effects of historic soil chemistry changes associated with acid rain, i.e., reduced soil pH and a shift from nitrogen (N)- to phosphorus (P)-limitation, on the coordination of leaf water demand and xylem hydraulic supply traits in two co-occurring temperate tree species differing in growth rate. Using a full-factorial design (N × P × pH), we measured leaf nutrient content, water relations, leaf-level and canopy-level gas exchange, total biomass and allocation, as well as stem xylem anatomy and hydraulic function for greenhouse-grown saplings of fast-growing Acer rubrum (L.) and slow-growing Quercus alba (L.). We used principle component analysis to characterize trait coordination. We found that N-limitation, but not P-limitation, had a significant impact on plant water relations and hydraulic coordination of both species. Fast-growing A. rubrum made hydraulic adjustments in response to N-limitation, but trait coordination was variable within treatments and did not fully compensate for changing allocation across N-availability. For slow-growing Q. alba, N-limitation engendered more strict coordination of leaf and xylem traits, resulting in similar leaf water content and hydraulic function across all treatments. Finally, low pH reduced the propensity of both species to adjust leaf water relations and xylem anatomical traits in response to nutrient manipulations. Our data suggest that a shift from N- to P-limitation has had a negative impact on the water relations and hydraulic function of A. rubrum to a greater extent than for Q. alba We suggest that current expansion of A. rubrum populations could be tempered by acidic N-deposition, which may restrict it to more mesic microsites. The disruption of hydraulic acclimation and coordination at low pH is emphasized as an interesting area of future study.

System design and control for waste heat recovery of automotive engines based on Organic Rankine Cycle

In this study, a novel and practical design for an ORC (Organic Rankine Cycle) system is presented. It can be applied to waste heat recovery of unsteady heat sources, such as exhaust gas of automobile engines. According to the variation characteristics of exhaust gas temperature and mass flow rate, the EGMR (Exhaust Gas Mixture Recirculation) loop is designed. The exhaust gas flowing out of the evaporator is partially recovered and mixed with the real-time engine exhaust gas, and then led to recirculation in the evaporator. Moreover, an energy storage module is also introduced, which is simplified as a metal block with internal tubes. A control approach based on ADRC (Active Disturbance Rejection Control is established. It is composed of an outer sub-loop controller for the evaporating pressure, a control allocator for mass flow rate allocation of the exhaust gas, and an inner sub-loop controller for the valve openings. The system is evaluated according to the numerical simulations. The results show that it can work steadily and reliably. The control error of the evaporating pressure is lower than 0.1%, and the fluctuation of the superheating is less than 1 °C. Compared with the conventional ORC system, both the cycle and the overall energy efficiencies are increased significantly. Furthermore, since no extra thermodynamic cycle or working fluid is demanded, the system architecture is more practical and simpler than most previous designs of system improvement.

Sexual differences in morphology and aboveground biomass allocation in relation to branch number in Morus alba saplings

The effect of branch number on crown size and biomass accumulation has been reported for many trees, but knowledge about sexual differences in growth and aboveground biomass allocation related to branch number is still limited. Morus alba L. is a dioecious plant of economic importance, and was employed as a model species in our study. Thirty male and 30 female 1-month-old M. alba saplings with single or multiple (five) primary branches were cultivated for one growing season. Sexual differences in gas exchange, morphology, biomass accumulation and allocation, and relationships among morphological and biomass traits were investigated. Branch multiplication significantly increased the total leaf number, total leaf area, total leaf mass, aboveground mass, leaf : stem biomass ratio and specific leaf area at the plant level but decreased net photosynthetic rate (Pn), leaf number, mean single-leaf area, stem length, basal diameter and branch biomass at the branch level. Five-branch male saplings exhibited a significantly higher Pn, total leaf number, total leaf area, total leaf mass and aboveground biomass than did female ones. No such between plant sex differences were found in single-branch saplings. Further, branch number was positively correlated with aboveground mass in male saplings only. Our results demonstrate that branch multiplication might result in sexual differences in morphology and biomass accumulation and male saplings may allocate greater resources than females to aboveground parts for vegetative growth.

连续气举井组优化配气研究

连续气举井组优化配气研究

Development of a time-dependent economic method with start time consideration to optimise gas-lift allocation and scheduling

The gas lift allocation optimisation is an important operational problem. In this paper, we present a method to optimise the lift gas allocation profile and determine the best time to start the gas-lift operation for each well. To tackle the nonlinear optimisation, an estimation of distribution algorithm (EDA) is employed based on Gaussian Bayesian networks and Gaussian kernels and the results are compared with those obtained by particle swarm optimisation (PSO) and genetic algorithms (GAs). Gas-lift performance for all the wells along with estimated cumulative production data are correlated over time to develop a model to show the field production behaviour as a function of the gas injection rates and initiation parameters. The developed model is coupled with an economic model to maximise the net present value of the gas-lift process for the field. [Received: 7 September 2014; Accepted: 30 September 2015]

Numerical Study of the Reduction Process in an Oxygen Blast Furnace

Based on computational fluid dynamics, chemical reaction kinetics, principles of transfer in metallurgy, and other principles, a multi-fluid model for a traditional blast furnace was established. The furnace conditions were simulated with this multi-fluid mathematical model, and the model was verified with the comparison of calculation and measurement. Then a multi-fluid model for an oxygen blast furnace in the gasifier-full oxygen blast furnace process was established based on this traditional blast furnace model. With the established multi-fluid model for an oxygen blast furnace, the basic characteristics of iron ore reduction process in the oxygen blast furnace were summarized, including the changing process of the iron ore reduction degree and the compositions of the burden, etc. The study found that compared to the traditional blast furnace, the magnetite reserve zone in the furnace shaft under oxygen blast furnace condition was significantly reduced, which is conducive to the efficient operation of blast furnace. In order to optimize the oxygen blast furnace design and operating parameters, the iron ore reduction process in the oxygen blast furnace was researched under different shaft tuyere positions, different recycling gas temperatures, and different allocation ratios of recycling gas between the hearth tuyere and the shaft tuyere. The results indicate that these three factors all have a substantial impact on the ore reduction process in the oxygen blast furnace. Moderate shaft tuyere position, high recycling gas temperature, and high recycling gas allocation ratio between hearth and shaft could significantly promote the reduction of iron ore, reduce the scope of the magnetite reserve zone, and improve the performance of oxygen blast furnace. Based on the above findings, the recommendations for improvement of the oxygen blast furnace design and operation were proposed.

Stabilizing gas lift optimization with different amounts of available lift gas

One of the problems that sometimes occurs in gas lift operations is the instability phenomenon. This phenomenon reduces the oil production and damages down hole and surface facilities. There are many studies on different aspects of this problem but none of them have focused on this phenomenon in a gas allocation optimization problem. Here, as a new approach, instability has been prevented by considering it in the design stage of a gas allocation optimization problem. In this paper, six wells of the Iranian oil field were selected and different amounts of lift gas were allocated among them in a way that the total production was maximized. In each case, the effect of the considering stability was discussed. In addition, about 2000 other wells were investigated to see whether there is any safe situation in which gas allocation optimization can be carried out without any concern about instability. The results indicated that in any case (no matter how much gas is available), it is probable that the optimum point be in an unstable region (of course with different probability). However, by using the method of this study, considering instability as a constraint for the optimizer can lead the optimum point to a stable region with a very small production loss.

A Nonlinear Programming Approach to Gas Lift Allocation Optimization

An attempt is made to model a gas lift allocation problem as a nonlinear optimization form with a wide range of constraints covering deficiencies carried out by past studies. In this article, a rigorous nonlinear ‎programming approach is used to maximize daily cash flow of a group of production wells under ‎gas lift operation. First, an appropriate model is prepared for gas lift performance curve of each well by use of nonlinear logarithmic and polynomial regression. Afterward, a model is constructed and solved for daily cash flow under capacity and pressure constraints. Results show a significant increase in cash flow for an optimized case compared with the current gas allocation plan. Moreover, sensitivity analysis was performed for different variables showing that oil price and compressing cost must be considered in long-term gas lift allocation optimization.

Optimal and Coordinated Functioning of Oil and Gas Wells

Typical production objectives in the lift gas assisted oil wells include stable and optimal production that meets demands on oil and gas. The attainment of these objectives in a typical production facility involving depletion of oil and gas, from a diversity of reservoirs that have different pressures, compositions, gas to oil ratios and natural flows. The objectives are also bound by constraints on compression and its costs, specifications on the export gas for pressure, volume and composition as per different customer end demands. While optimal allocation of the limited lift gas is desirable, an enterprise-wide, coordinated view of the production from the diverse gas or oil reservoirs would facilitate greater flexibility towards meeting the customer demands in an optimal manner. In this paper, we consider a smaller prototype of a production facility involving a low pressure, medium pressure and high pressure gas reservoirs, which also exhibit varying compositions, gas to oil ratios and natural flows. We propose a formulation that promotes co-ordination between these diverse reservoirs so as to honor the constraints on export gas or liquid pressures, compositions or natural flows. The results have been verified on a prototype of a three well production facility using a simulation model adapted from Jahanshahi et al. (2012).