Techno-Economic Analysis and Life Cycle Assessment for the Typical Intermediate Crude Refining Scheme in China

The integration of refinery and petrochemical units(IRPUs)has become an inevitable choice for the sustainable development of petrochemical industry.The utilization efficiency of petroleum resources could be improved obviously through IRPUs.However,integrating economic and environmental impacts into the model of IRPUs is still a grand challenge.Herein,a model called TEA-GHG-OPWM(Techno-Economic Analysis and GreenHouse Gases Oriented Plant-Wide Model)has been established on Aspen HYSYSTM platform to calculate the energy consumption,the technoeconomic performance,and the GHG emissions for two different kinds of schemes,viz,:VRHCU(Vacuum Residue Hydrocracking Unit)and VRDS-RFCC(Vacuum Residue Desulfurization and Residue Fluid Catalytic Cracking).Furthermore,a novel processing pathway named VGOHDT-HTMP-DC(Vacuum Gas Oil Hydrotreating,Hydrogenation and TMP coupling process and Delayed Coking)has also been developed to find methods to improve the economic performance based on a ten-million-CNY output value(TMYOV)and a reduced GHG emissions.Our results demonstrate that VRHCRU could consume more energy and emit more GHG(877.11 t of CO2 eq·TMYOV^-1·h^-1)than VRDS-RFCC(817.03 t of CO2 eq·TMYOV^-1·h^-1)and VGOHDT-HTMP-DC(721.96 t of CO2 eq·TMYOV^-1·h^-1),while obtaining a higher mass yield of petrochemicals.The VGOHDT-HTMP-DC process exhibits the lowest feedstock consumption,hydrogen consumption,energy consumption,and GHG emissions,indicating that VGOHDT-HTMP-DC has both well economic and environmentally friendly performance.

Techno-Economic Analysis of Power Production by Using Waste Biomass Gasification

Energy recovery from waste biomass can have significant impacts on the most pressing development challenges of rural poverty and environmental damages. In this paper, a techno-economic analysis is carried out for electricity generation by using timber and wood waste (T & WW) gasification in Iceland. Different expenses were considered, like capital, installation, engineering, operation and maintenance costs and the interest rate of the investment. Regarding to revenues, they come from of the electricity sale and the fee paid by the Icelandic municipalities for waste collection and disposal. The economic feasibility was conducted based on the economic indicators of net present value (NPV) and discounted payback period (DPP), bringing together three different subgroups based on gasifier capacities, subgroup a: 50 kW, subgroup b: 100 kW and subgroup c: 200 kW. The results show that total cost increases as the implemented power is increased. This indicator varies from 1228.6 k€ for subgroups a to 1334.7 k€ for subgroups b and 1479.5 k€ for subgroups c. It is worth mentioning that NPV is positive for three subgroups and it grows as gasifier scale is extended. NPV is about 122 k€ (111,020 $), 1824 k€ (1,659,840 $) and 4392 k€ (3,996,720 $) for subgroups a, b and c, respectively. Moreover, DPP has an inversely proportional to the installed capacity. It is around 5.5 years (subgroups a), 9.5 months (subgroups b) and 6 months (subgroups c). The obtained results confirm that using small scale waste biomass gasification integrated with power generation could be techno-economically feasible for remote area in Iceland.

Techno-Economic Analysis of a Grid-Connected Waste to Energy Gasification Plant:A Case Study

With population growth around the world,municipal waste disposal and continued energy demand becomes some of the major challenges to deal with.In order to address these,an approach is required for an optimal waste management system that offers the population benefit with a lower environmental impact.This study evaluates the technical-economic and environmental impact analysis of a grid-connected waste to energy(WtE)plant to power a Univerisiti Teknologi Malaysia(UTM)community.The energy recovery potential of the waste stream was assessed using the life cycle assessment(LCA)method with GaBi^(TM) software(version 4).A technical,economic and environmental analysis was then carried out for the grid-connected WtE system using HOMERPro software with gasification conversion technology.The cash flow analysis was based on levelized costs of energy(LCOE)and total net present value(NPV).The results gave an NPV for the system at USD 1.11×10^(7),with most of the effects resulting from the grid operating costs and the LCOE of USD 0.43/kWh compared to the grid unit price of USD 0.7/kWh which corresponds to a saving of$0.27/kWh in energy purchase.From an environmental point of view,the results showed a significant reduction in carbon dioxide emissions from around 2,000 tons per year to around 400 tons per year.With regard to the amount of waste sent to landfills,the results show a significant improvement from 142,605.5 kg/year to 0.13 kg/year.

Techno-economic analysis of single U-tube and double U-tube heat exchangers in Chongqing area

On the basis of practical projects in Chongqing,the thermal performance of heat exchangers (single U-tube type and double U-tube type) of the ground-source heat pump (GSHP) system in the hot summer was obtained and analyzed. The data obtained from test could match with the result deduced from theoretical calculation. From the test results,the cooling capacity of double U-tube is 1.6 times that of single U-tube. Taking cost per depth per watt Clq as the evaluation standard,Clq of single U-tube is 4.69 RMB$/W,and Clq of double U-tube is 3.14 RMB$/W. The double U-tube heat exchangers usage should be prioritized.

Techno-economic Analysis of Distributed Hydrogen Production from Natural Gas

It is well established that hydrogen has the potential to make a significant contribution to the world energy production.In U.S.,majority of hydrogen production plants implement steam methane reforming(SMR) for centralized hydrogen production.However,there is a wide lack of agreement on the nascent stage of using hydrogen as fuel in vehicles industry because of the difficulty in delivery and storage.By performing technological and economic analysis,this work aims to establish the most feasible hydrogen production pathway for automotives in near future.From the evaluation,processes such as thermal cracking of ammonia and centralized hydrogen production followed by bulk delivery are eliminated while on-site steam reforming of methanol and natural gas are the most technologically feasible options.These two processes are further evaluated by comprehensive economic analysis.The results showed that the steam reforming(SR) of natural gas has a shorter payback time and a higher return on investment(ROI) and internal rate of return(IRR).Sensitivity analysis has also been constructed to evaluate the impact of variables like NG feedstock price,capital of investment and operating capacity factor on the overall production cost of hydrogen.Based on this study,natural gas is prompted to be the most economically and technologically available raw material for short-term hydrogen production before the transition to renewable energy source such as solar energy,biomass and wind power.

Modifying Plant Oils for Use as Fuel in Rural Contexts Tanzania: Techno-Economic Analysis

Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.

Thermodynamic and Techno-economic Analysis of a Triple-pressure Organic Rankine Cycle: Comparison with Dual-pressure and Single-pressure ORCs

Investigation of a triple-pressure organic Rankine cycle(TPORC) using geothermal energy for power generation with the net power output of the TPORC analyzed by varying the evaporation pressures, pinch temperature differences(tpp) and degrees of superheat(tsup) aimed to find the optimum operation conditions of the system. The thermodynamic performance of the TPORC was compared with a dual-pressure organic Rankine cycle(DPORC) and a single-pressure ORC(SPORC) for geofluid temperatures ranging from 100°C to 200°C, with particular reference to the utilization of a hot dry rock(HDR) geothermal resource. Thermodynamic performances of the TPORC system using eight different organic working fluids have also been investigated in terms of the net power outputs. Results show that a higher geofluid mass flow rate can make a considerable contribution to shortening the payback period(PBP) as well as to decreasing the levelized electricity cost(LEC), especially when the geofluid temperature is low. For the temperature range investigated, the order from high to low based on thermodynamic and techno-economic performances is found to be TPORC > DPORC > SPORC. In terms of using geothermal resources within the given temperatures range(100°C–200°C), the TPORC system can be a better choice for geothermal power generation so long as the wellhead geofluid temperature is between 140°C and 180°C.

Thermal pyrolysis conversion of methane to hydrogen(H_(2)):A review on process parameters,reaction kinetics and techno-economic analysis

Hydrogen(H_(2))is a promising renewable energy which finds wide applications as the world gears toward low-carbon economy.However,current H_(2) production via steam methane reforming of natural gas or gasification of coal are laden with high CO_(2) footprints.Recently,methane(CH_(4))pyrolysis has emerged as a potential technology to generate low-carbon H_(2) and solid carbon.In this review,the current state-of-art and recent progress of H_(2) production from CH_(4) pyrolysis are reviewed in detail.Aspects such as funda-mental mechanism and chemistry involved,effect of process parameters on the conversion efficiency and reaction kinetics for various reaction media and catalysts are elucidated and critically discussed.Temper-ature,among other factors,plays the most critical influence on the methane pyrolysis reaction.Molten metal/salt could lower the operating temperature of methane pyrolysis to<1000℃,whereas plasma technology usually operates in the regime of>1000℃.Based on the reaction kinetics,metal-based cata-lysts were more efficient in lowering the activation energy of the reaction to 29.5-88 kJ/mol from that of uncatalyzed reaction(147-420.7 kJ/mol).Besides,the current techno-economic performance of the pro-cess reveals that the levelized cost of H_(2) is directly influenced by the sales price of carbon(by-product)generated,which could offset the overall cost.Lastly,the main challenges of reactor design for efficient product separation and retrieval,as well as catalyst deactivation/poisoning need to be debottlenecked.

Techno-economic Analysis of Wind Curtailment/Hydrogen Production/Fuel Cell Vehicle System with High Wind Penetration in China

Wind curtailment/hydrogen production/fuel cell vehicle system(WCHPFCVS)is the use of curtailment to electrolyze water to produce hydrogen,which then provides energy for hydrogen fuel cell vehicles.In this paper,a techno-economic analysis of WCHPFCVS is proposed using the HOMER software.Large-scale wind power penetration is expected to lead to serious wind curtailment,and therefore,the hydrogen fuel cell vehicle will play an important role in future renewable energy storage,energy internet sharing,and electric transport areas.A system model of wind curtailment/hydrogen production/fuel cell vehicle is presented and analyzed using HOMER software to optimize the capacity and cost of the system.An annual revenue and profit of the system is then calculated and analyzed for energy conservation,emissions reduction,and environmental benefits.A technoeconomical evaluation of the system when cost of producing hydrogen and hydrogen load(fuel cell vehicle quantities)changes is also presented,taking into consideration the future progress of the technology and its market development.Techno-economic analysis of WCHPFCVS is shown as an effective method through a case study using actual data of curtailment from a wind farm in Jilin province in northeast China.

Techno-economic analysis of the adoption of electric vehicles

Significant advances in battery technology are creating a viable marketspace for battery powered passenger vehicles.Climate change and concerns over reliable supplies of hydrocarbons are aiding in the focus on electric vehicles.Consumers can be influenced by marketing and emotion resulting in behaviors that may not be in line with their stated objectives.Although sales of electric vehicles are accelerating,it may not be clear that purchasing an electric vehicle is advantageous from an economic or environmental perspective.A technoeconomic analysis of electric vehicles comparing them against hybrids,gasoline and diesel vehicles is presented.The results show that the complexity of electrical power supply,infrastructure requirements and full life cycle concerns show that electric vehicles have a place in the future but that ongoing improvements will be required for them to be clearly the best choice for a given situation.

Comparative techno-economic analysis of large-scale renewable energy storage technologies

Energy storage is an effective way to address the instability of renewable energy generation modes,such as wind and solar,which are projected to play an important role in the sustainable and low-carbon society.Economics and carbon emissions are important indicators that should be thoroughly considered for evaluating the feasibility of energy storage technologies(ESTs).In this study,we study two promising routes for large-scale renewable energy storage,electrochemical energy storage(EES)and hydrogen energy storage(HES),via technical analysis of the ESTs.The levelized cost of storage(LCOS),carbon emissions and uncertainty assessments for EESs and HESs over the life cycle are conducted with full consideration of the critical links for these routes.In order to reduce the evaluation error,we use the Monte Carlo method to derive a large number of data for estimating the economy and carbon emission level of ESTs based on the collected data.The results show that lithium ion(Li-ion)batteries show the lowest LCOS and carbon emissions,at 0.314 US$kWh-1 and 72.76 g CO_(2) e kWh^(-1),compared with other batteries for EES.Different HES routes,meaning different combinations of hydrogen production,delivery and refueling methods,show substantial differences in economics,and the lowest LCOS and carbon emissions,at 0.227 US$kWh^(-1) and 61.63 gCO_(2) e kWh^(-1),are achieved using HES routes that involve hydrogen production by alkaline electrolyzer(AE),delivery by hydrogen pipeline and corresponding refueling.The findings of this study suggest that HES and EES have comparable levels of economics and carbon emissions that should be both considered for large-scale renewable energy storage to achieve future decarbonization goals.

Preliminary techno-economic analysis of three typical decentralized composting technologies treating rural kitchen waste:a case study in China

This study was designed to evaluate whether the decentralized rural kitchen waste(KW)composting technologies used in China can be widely applied.To this end,we completed a techno-economic analysis of three typical types of KW compositing,namely solar-assisted(SAC),bio-enhanced(BEC),and heat-dewatering composting(HDC).These evaluations revealed that all three technologies produce composting products that meet China’s organic fertilizer standard and that both SAC and BEC are economically self-sustaining and generate net profits(18824.94 and 17791.52 US$/a)and positive net present values(32133.11 and 25035.93 US$).Subsequent sensitivity analysis demonstrated that the KW-handling subsidy plays a critical role in making decentralized composting economically attractive.Based on these analyses,we believe that reducing the coverage area of SAC,reducing the operating cost of BEC and HDC,upgrading composting products,and strengthening secondary pollution control would aid in supporting the technological improvement of these processes.Moreover,providing appropriate subsidies and promulgating specific standards and policies for KW fertilizer are key strategies for decentralized rural KW composting management.

Life-cycle assessment and techno-economic analysis of the production of wood vinegar from Eucommia stem: a case study

This research undertook a case study of the life-cycle assessment and techno-economic analysis of the slow pyrolysis of Eucommia stem for the production of wood vinegar and activated carbon.The results showed that the production of one ton of wood vinegar via the slow pyrolysis of Eucommia stem show comparatively low global warming potential(2.37×10^(2) kg CO_(2) eq),primary energy demand(3.16×10^(3) MJ),acidification potential(2.19 kg SO2 eq),antimony depletion potential(3.86×10^(–4) kg antimony eq),and ozone depletion potential(7.46×10^(–6) kg CFC-11 eq)and was more environmentally friendly than the production of dilute acetic acid(12 wt%)via petrochemical routes.Meanwhile,the total capital investment,total product cost,and cash flowsheet were provided in the techno-economic analysis.Then,the net present value,internal rate of return,and dynamic payback period of the production process were evaluated.The findings indicated that while this production process is cost-effective,it might not be economically attractive or could generate investment risks.An increase in the added value of the wood vinegar and the activated carbon could remarkably improve the economic feasibility of this production process.

Prognostics and health management of alkaline water electrolyzer: Techno-economic analysis considering replacement moment

Recently,considerable attention has been paid to the installation of renewable energy capacity to mitigate global CO_(2) emissions.H_(2) produced using water electrolysis and renewable energy is regarded as a clean energy carrier,generating electricity without CO_(2) emissions,called‘Green H 2’.In this paper,a prognostics and health man-agement model for an alkaline water electrolyzer was proposed to predict the load voltage on the electrolyzer to obtain the state of health information.The prognostics and health management model was developed by training historical operating data via machine learning models,support vector machine and gaussian process regression,showing the root mean square error of 1.28×10^(−3) and 8.03×10^(−6).In addition,a techno-economic analysis was performed for a green H_(2) production system,composed of 1 MW of photovoltaic plant and 1 MW of alkaline water electrolyzer,to provide economic insights and feasibility of the system.A levelized cost of H_(2) of$6.89 kgH_(2)−1 was calculated and the potential to reach the levelized cost of H_(2) from steam methane reforming with carbon capture and storage was shown by considering the learning rate of the photovoltaic module and elec-trolyzer.Finally,the replacement of the alkaline water electrolyzer at around 10 years was preferred to increase the net present value from the green H_(2) production system when capital expenditure and replacement cost are low enough.

Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling Systems

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and petroleum.To achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is required.This study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling equipment.The study specifically investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency stick-slip.These events not only hinder the efficiency of drilling but also lead to exhaustion and harm to the system’s components since they are difficult to be detected and controlled in real time.The study investigates the dynamic interactions of these vibrations,specifically in their high-frequency modes,usingfield data obtained from measurement while drilling.Thefindings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem performance.The obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control systems.Therefore,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect damage.Moreover,by exploiting thesefindings,the assessment of structural resilience in rotary drilling systems can be enhanced.Furthermore,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efficiency of rotary drilling systems in the petroleum industry.

Research status and prospects of the fractal analysis of metal material surfaces and interfaces

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine properties.Fractal analysis has been used to characterize the shapes of metal materials at various scales and dimensions.Conventional methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and interfaces.However,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal materials.From the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear surfaces.The relationship between the fractal dimensions and properties of metal material surfaces and interfaces is summarized.Starting from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be developed.It is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

Multilevel analysis of the central-peripheral-target organ pathway:contributing to recovery after peripheral nerve injury

Peripheral nerve injury is a common neurological condition that often leads to severe functional limitations and disabilities.Research on the pathogenesis of peripheral nerve injury has focused on pathological changes at individual injury sites,neglecting multilevel pathological analysis of the overall nervous system and target organs.This has led to restrictions on current therapeutic approaches.In this paper,we first summarize the potential mechanisms of peripheral nerve injury from a holistic perspective,covering the central nervous system,peripheral nervous system,and target organs.After peripheral nerve injury,the cortical plasticity of the brain is altered due to damage to and regeneration of peripheral nerves;changes such as neuronal apoptosis and axonal demyelination occur in the spinal cord.The nerve will undergo axonal regeneration,activation of Schwann cells,inflammatory response,and vascular system regeneration at the injury site.Corresponding damage to target organs can occur,including skeletal muscle atrophy and sensory receptor disruption.We then provide a brief review of the research advances in therapeutic approaches to peripheral nerve injury.The main current treatments are conducted passively and include physical factor rehabilitation,pharmacological treatments,cell-based therapies,and physical exercise.However,most treatments only partially address the problem and cannot complete the systematic recovery of the entire central nervous system-peripheral nervous system-target organ pathway.Therefore,we should further explore multilevel treatment options that produce effective,long-lasting results,perhaps requiring a combination of passive(traditional)and active(novel)treatment methods to stimulate rehabilitation at the central-peripheral-target organ levels to achieve better functional recovery.

Application and progress of techno-economic analysis and life cycle assessment in biomanufacturing of fuels and chemicals

To reduce the dependency on petroleum-based products and emission of greenhouse gas,renewable biofuels and chemicals play an important role to meet the unmatched energy demands of the rapidly growing population.However,most biofuel and chemical products do not reach the commercialization stage,mainly hindered by incomparable economics to petroproducts.Techno-economic assessment(TEA)is a useful tool to estimate eco-nomic performance,and identify bottlenecks for the development of biofuel and chemical production technology,meanwhile,life cycle assessment(LCA)is applied to assess sustainability by reducing the environmental impact of biofuel and chemical production.This present review covers TEA and LCA research progress in the manufacturing of biofuels and biochemical,and discusses the impacts of TEA and LCA results on the development and optimi-zation of biofuel and chemical production.In addition,challenges associated with TEA and LCA of biofuel and biochemical production were briefly overviewed,and potential approaches that may overcome such challenges were discussed enabling viable and sustainable biomanufacturing of fuels and chemicals.Future integrated TEA and LCA studies could significantly promote the economic and sustainable development of the biomanufacturing process.

Techno-Economic Feasibility Analysis of Solar Photovoltaic Power Generation: A Review

With the rapid depletion of fossil fuel reserves, it is feared that the world will soon run out of its energy resources. This is a matter of concern for developing countries whose economy heavily leans on its use of energy. Under the circums-tances it is highly desirable that renewable energy resources should be utilized with maximum conversion efficiency to cope with the ever increasing energy demand. Furthermore, the global economic and political conditions that tend to make countries more dependent on their own energy resources have caused growing interest in the development and use of renewable energy based technologies. In terms of its environmental advantages, renewable energy sources generate electricity with insignificant contribution of carbon dioxide (CO2) or other greenhouse gases (GHG) to the atmosphere and they produce no pollutant discharge on water or soil and hence power generation from renewable becomes very important. Major types of renewable energy sources include solar, wind, hydro and biomass, all of which have huge potential to meet future energy challenges. Solar photovoltaic technology in one of the first among several renewable energy technologies that have been adopted worldwide for meeting the basic needs of electricity particularly in remote areas. In this paper literature review pertaining to techno-economic feasibility analysis of solar photovoltaic power generation is discussed. The literature is basically classified into the following three main category design methods, techno-economic feasibility of solar photovoltaic power generation, performance evaluations of various systems.

Techno-economic analysis on oxy-fuel based steam turbine power system using municipal solid waste and coals with ultrasonicator sulfur removal

Municipal solid waste(MSW)is a carbon–neutral energy source and possesses a moderate heating value;hence,it can be used as an alternative fuel for coal.To use high ash and high sulfur Indian coals efficiently,a techno economic analysis is performed for electricity generation using supercritical and subcritical based steam turbines operating in the oxy-fuel co-combustion mode of MSW with Indian coals.The impact of the capture of direct and indirect greenhouse gasses such as CO_(2),NO_(x)and SO_(x)on the net thermal efficiency of the power plants is assessed.The supercritical based steam turbine achieved a higher net thermal efficiency by 8.8%using MSW based feedstock compared to sub-critical conditions.The co-combustion mode reduced the levelized cost of electricity(LCOE)by 48–73$/MWh.Techno-economic analysis for sulfur removal in coal using ultrasonication technology has not yet been reported in the literature.The incorporation of an ultrasonicator(a pre-combustion sulfur remover)and a duct sorbent injector(a post-combustion SO_(x)absorber)increased the LCOE by 1.39–2.75$/MWh.In high sulfur coals,the SO_(x)emissions decreased from 224.79 mg/m^(3)to 9.2 mg/m^(3).