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Tuesday, April 2, 2019

What Is Green Diesel Environmental Sciences Essay

What Is b everypark Diesel Environmental Sciences EssayGreen Diesel, much called renewable diesel engine motor engine or second generation diesel, refers to petrodiesel- deal burn d professs gain groundd from biologic sources boundinates derived from biological resources (bio-resources) that atomic number 18 chemicly not esters and thus distinct from biodiesel. The jet plane diesel is chemically homogeneous as petrodiesel nevertheless it is made from bio-resources. Bio-resources refers to the living things (plants, savages, and some early(a)s aspects of nature). It is Coperni scum bag to society for the variant services they render, as well as problems they whitethorn create. Biological resources be grouped into those that affect agriculture, such(prenominal)(prenominal) as obliging plants, pollinators, and pests those that be sources of scientific inputs, such as agricultural plant varieties that provide genetic resources and those that provide natural fulls and services, such as wildlife, fish, and scenic beauty. tralatitious measures of agricultural ingatheringivity do not capture all the benefits of preserving biological resources on private stains. Because of this, private degradeowners whitethorn not deplete enough incentives to consider the full range of goods and services contractd by the biological resources at a lower place their control. Since common land diesel is defecated by bio-resources, thus it is the eco-friendly and sustainable sources of give the sack for vehicles.Green diesel ruffles follow the same nomenclature as biodiesel. Green diesel in its pure form is designated R100 term a blend comprised of 20% grand diesel and 80% petrodiesel is called R20. Because blue jet diesel is chemically the same as petrodiesel, it whoremongerful be mixed with petrodiesel in any residual that users may command to add an running(a) to address lubricity abridge associated with compounds with no type O. Th e reference workistic of verdure diesel compared with some other fuel are sightn at a lower placeBiodieselDieselOxygen, %0110Specific gravity0.780.880.84Sulphur, ppmHeating order, C443843Cloud point, C-20 to 20-5 to 15-5Cetane70-9050-6540Table 1.1(1) Characteristics of Green Diesel compared with other fuel.Green diesel tidy sum be made from the same feedstock as biodiesel since twain are required the tricylglycerol containing material from bio-resources. date 1.1(1) Brief renewable Fuel Creation Process Pathway merely the terminations gullible diesels draw been further distinguished establish on the changeing order to create the fuel. The primary differences between putting surface diesel and biodiesel are the technologies utilize to contact the fuel and the molecules that are ultimately produced. Whereas, biodiesel is made apply a chemical response called transesterfication. There are three divers(prenominal) subr turn outinees for creating green diesel, hydr otreating, caloric depolymerisztion, and biomass-to-liquid (BTL). Green diesel blends follow the same nomenclature as biodiesel. Green diesel in its pure form is designated R100 while a blend comprised of 20% green diesel and 80% petrodiesel is called R20. Because green diesel is chemically the same as petrodiesel, it can be mixed with petrodiesel in any proportion but users may need to add an additive to address lubricity issue associated with compounds with no oxygen. The differences between green diesel and biodiesel are shown belowGreen DieselBiodieselPure hydro degree CelsiusOxygenated hydrocarbon crosswayion routineHydrotreating caloric depolymerisationBiomass-to liquid (BTL) achievement sourTranesterficationChemically same with petrodieselChemically different than petrodiesel.Table 1.1(2) Comparison of Green Diesel and Bio-dieselThe hydrotreating solve is a function utilized by petroleum refineries today to re geological fault elaborate contaminants such as sulphur, ni trogen, condensed ring aromatics, or coats.1.1.2 Importance of Green Diesel from Malaysia Chemical manufacture Point of ViewDiesel anele has good commercial value as it serve many an(prenominal) purposes. It has many functions as belowTo apparent movement the heavy road vehicles such as buses, lorries and trucks.To move motors and carsFor oerland conveyanceTo move mili lurchy vehicles, such as tanksCan be use in the water transportation as an alternative might sources to move engines such as in the ships, boats and yachtAs electricity sculptural relief talent sourcesPower generationConstruction and farming equipmentRemoval of tar from bitumen burnsThey derived the diesel from sodding(a) rock crude, which is called petrodiesel. With sharply rising use of non-renewable feedstock (crude oil) to derive diesel has a meaning(a) impact on the toil of biofuels based on the conventional order. A projected futurity shortage of crude oil coupled with the growing worldwide aim for transportation fuels has increase the interest in the green diesel, which chemically has the same properties as the petrodiesel but with fall apart cetane number, which mean reduce the expelling of CO2 and NOx, emission, and thus brings large improvement on greenhouse effect, global warming and pollutions.Figure 1.1(2) period and Future Trend of merchandise for PetroleumFor recent studies and ripening of technologies show that the performance of green diesel can be competitive or cost less than petroleum fuels yield to a capitaler extent oil per hectare of land sequester CO2 from the flue gasolinees emitted from fossil fuel power plants or other resources able to same or even awaystanding public presentation than petroleum fuels improvement of cold flow properties so that it cause least(prenominal) problem to use during winter. The advantages of green diesel compared with others type of diesel can be summarised as belowGreen diesel does appear to have many advantag es everyplace the other bio-based diesels. Some of these potential advantages are summarized belowThe process utilizes existing refining trading operations thereby eliminating the need for the big capital investment required in the United States to produce a significant amount of biodiesel capable of truly displacing significant amounts of petroleum diesel.The fuel is produced by refineries with a broad track record of safely producing lavishly grade products thereby eliminating the uncertainty of a fuel produced by a large number of in interdependent producers with limited experience in fuels takings.The producers can utilize existing transportation and storage capacity (pipelines, tankage, trucks, etc.) thus eliminating the need for establishing a separate system. It should be noted that overdue to the detergent character of biodiesel, it cannot be transported or stored in existing petroleum facilities.This industry places production of a fuel in the hands of companies wi th significant experience with the trade and distribution of fuel products.The process utilizes a spirited portion of the lipids, such as the glycerin conversion to propane.Currently green diesel appears to have quasi(prenominal) processing cost as biodiesel.The resulting fuel appears to have more(prenominal) stable fluid and burn properties at low temperaturesMalaysia too has her own biofuel policy. The government has announced the introduction of a National Biofuel Policy on 10 August 2005. The policy is primarily aimed at reducing the countrys fuel import bill, promoting further the read for palm oil which go forth be the primary commodity for biofuel production (alongside regular diesel). One of the four strategies in Malaysias National Biofuel Policy is to encourage the use of biofuel among the public, which will involve good-looking out incentives for oil retail companies to provide biodiesel pumps at stations 6. From this policy, we can conclude that our country start ed to pay attention to biofuels.However, with the green diesel stands out to be having more advantages than bio-diesel, the forecast of green diesel in Malaysia would be off the bright star. With all the bio-resources readily on hand(predicate) as feedstock in the production of green diesel, definitely green diesel will be maven of the virtually potential alternative energies utilized in the land of Malaysia.1.1.3 The World Green Diesel Production PlantsGreen diesel is a new breed of fats-and-oils based renewable diesel is now change magnitude its presence in the global biofuels market as major players stared up new production facilities this year. Efforts are being made all over the world to replace fossil fuel. We are belatedly realized that non-renewable efficiency is cause us serious problems and that is the main cause to develop more alternative talent resources. Green diesel can be produced either by hydrotreating process, BTL reaction or thermal depolymerization proc esses. Its chemical properties are analogous to petroleum diesel as compared with bio-diesel.The demand of green diesel is so much interesting but to a fault challenging. In Malaysia, the usage of green diesel is not much significant. But, recently, there is new renewable brawniness pilot plant being launched by Saham Utama Sdn. Bhd. in Sungai Batu Pahat near Kangar, Perlis. The diesel is made from unwavering extravagance malleable. This can reduce the amount of plastic barrens, thereby helping to combat the effect of global warming. They have claimed that the added features would be installed to transform plastic bottles into diesel fuel. The goal is to convert any domesticated waste including organic waste and liquid into commercial fuels. The engineering method used could be thermal depolymerization which similar to cracking of crude oil.In Asia, the most nearest country which recently alert about these efforts is capital of Singapore. In November 2010, Finland-based Neste rock oil started the world largest renewable diesel plant in Singapore, with a sum capacity of 725 760 tonnes per year. The diesel produced is feeln as NExBTL, a premium-quality product with knotty production engineering science and likewise more expensive than bio-diesel. It is produced by hydrotreating of the feedstock. The byproducts of the process are bio-gasoline, biogas and water. The feedstock being used is palm oil. However, Neste Oils NExBTL can too use rapeseed oil and waste animal fat from food industry. This make the technology becomes more flexible due to availability of feedstocks in the future. Neste Oil also has an intensive research on new materials for future needs.In Europe, the renewable diesel is experiencing oversupply and Neste Oil exacerbate their plant at Rotterdam in 2011. The renewable plants also could be exacerbated rising fats and oil prices because of the feedstock demand including in US. Researchers claimed that the global renewable diesel cap acity totals about 665 meg gallon per year today and this will grow up to 2.5 cardinal gallon per year in 2015, a 33% annual growing. under is the summary make of companies that produce green diesel (worldwide) technologyFeedstockProduct commercialised EntityCommercial StatusOutstanding Commercial IssuesHydrotreatingAnimal fats or vegetable oils co-processed with petroleum dieselHydrocarbon mixture- meets ASTM D975Conoco Philips/ TysonIreland refinery producing since Dec. 2006.US announced production of clxxv million gals/year judge by 2009EPA registrationToxicity and biodegradabilityHydrocarbon mixture- meets case fuel quality standards in AustraliaBPAustralian refinery producing 5% renewable blendAnimal fats/ vegetable oilsHydrocarbon mixture- meets ASTM D975Neste oilFirst plant in Finland with capacity of 58 million gals/yearThe largest plant available in Singapore with production of 0.8 million tons/yearAlso located in US and NetherlandsEPA registrationToxicity and biodegr adabilityMarketplace useHydrocarbon mixturePetrobras (Brazil,H-Bio Technology) pay off at several refineries since end of 2007Animal fatsHydrocarbon mixtureDynamic fuels (Syntroleum/Tyson)Commercial pilot started I n 2008Production start in 2010 metre developmentEPA registrationEconomicsLife-cycle outlineToxicity and biodegradabilityVegetable oilsUOP TechnologyPlant constructed in 2009Production of 95 million gals/yearBiomass-to-Liquid (BTL) via gasification or Fischer-TrophsBiomassHydrocarbon mixtureJV with Choren/ Daimler-Chrysler/VWPilot plant opened in 2007Production 0f 4.7 million gals/yearStandard developmentEPA registrationEconomicsLife-cycle analysisToxicity and biodegradabilityNeste Oil/ Stora EnsoPre-commercializationSyntroleumPyrolysis-Rapid thermic ProcessingBiomass, municipal and industrial wasteHydrocarbon mixtureIn research formIn research stageStandard developmentEPA registrationEconomicsLife-cycle analysisToxicity and biodegradabilitybutchery waste (animal waste), carbon containing wasteHydrocarbon mixture- meets ASTM D396, can be refined to ASTM D975ever-changing World TechnologiesCommercial pilot plant in MissouriProduction of 250 000 gals/moles of slaughterhouse wasteMarketplace useTable 1.1(3) Summary list of companies in worldwide that produce green diesel1.1.4 Emerging pushing Demands for next 10 yearsMalaysia is currently in the midst of rapid development. One significant sign of rapid development is the increasing trending of faculty demands in the future. Not alone in Malaysia, the global energy beautify is changing tremendously, but most of it is showing an upward trend. Global energy demands will be about 30 percent advanceder in 2040 compared to 2010, as economical output more than doubles and prosperity expands crosswise a world whose population will grow by more than 25 percent, reaching to nearly 9 billion people. 1 Global demand for the least carbon-intensive fuels natural gas, nuclear and renewables will rise at a faster-than-average rate.CUsersDellDesktopDesignfuture trendCapture8.PNGFigure 1.1(3)Global energy demand increases by tercet from 2010 to 2035, with China and India accounting for 50 percent of the growth in the sunrise(prenominal) Policies Scenario 2In the above graph, the main growth of energy demands more significant in China and Asia due to the increasing population and fast-paced development of the countries. Malaysia falls under the category of Other developing Asia. Similarly it also shows an incline trend due to the rapid development of industrial and economic activities in Malaysia.In order to cope with the in high spirits rising of energy, respective(a) energy policies and plan were carried out by the government. Go Green is one of the most popular concept practice in the world wide, and the term renewable and sustainable is now related to oil and gas by having renewable diesel (green diesel). Many countries in the world often started on the production of green diesel using various types of technologies such as hydro-treating or thermal depolymerisation.CUsersDellDesktopCapture.PNGFigure 1.1(4) United State production of petroleum and other liquids by source, 2010-2035 (millions lay per day) 3By referring to the graph above, the total production of petroleum and other liquids grows rapidly, from 9.7 million barrels per day in 2010 to 12.1 million barrels per day in 2020. Focusing on renewable sources, prediction shows that the biofuel productions grows by 0.8 million barrels per day from 2010 to 2035 as a result of the EISA2007 RFS (Renewable Fuel Standard Program), with ethanol and biodiesel accounting for 0.7 and 0.1 billion barrels per day, respectively, of the increase in the Reference case. 3 In addition, incline trending of next-generation xTL production (including both biomass-to-liquids and CTL) contributes greatly to the growth in total production of petroleum and other liquids in U.S., especially significant after the year 2020. The s ignificant growth of BTL reflects a good potential in the future market, and yet it is a convincing and promising source of renewable diesel.Not simply on the growing capacity of green diesel production giving desires to mankind, the straight researches done by scientists also bring upon the increasing quality of green diesel. Before that, economic crisis and technological hurdles delay the start of many researches and projects on advanced biofuels, especially on cellulosic biofuel projects. However in the futures, it is expected that, EPA (Environment Protection Agency) will year-to-year evaluate the status of biofuel capacity and also edict on the production mandates for the following year. By the continuous efforts from researchers, it is foresee that BTL will reach the EISA2007 Renewable Fuel Standard after 2030. This providing a better quality or standard of green diesel produced.CUsersDellDesktopCapture2.PNGFigure 1.1(5) EISA2007 Renewable Fuel Standard credits earned in selected years, 2010-2035 (billion credits) 3However in Malaysia, a sad scenario is that the production of green diesel slake in an infant stage. Researches and developments in experimental scales had been carried out so far, but as yet the production in large industrial scale is still underdeveloped. By taking reference of the forecast on oil and gas field in U.S., rough estimation on the future hope of green diesel production in Malaysia for the next 10 years can be done. The potential of green diesel in the future 10 years of view in Malaysia is consider as a bright one, and to be believed that it will slowly increasing in demands over the next 10 years. Green diesel production in Malaysia is what we are looking for in the future. Scientists and fuel specialists optimistically believe that green or renewable diesel will be one of the future trends in oil and gas production, not only in Malaysia but also in the nationwide.1.2 PROCESS ALTERNATIVEGreen diesel is being super looke d up to as one of the great hope, with its similar chemical properties similar to diesel. New ways and technologies for improvement in green diesel production are improved as time go by. Of these, three processes of green diesel production will be suggested and discussed from different aspects.1.2.1 Production of green diesel via biomass to liquid technology and Fisher-Tropsch ProcessOne of the alternative processes is to produce green diesel is by using Fischer-Tropsch process. It is basically a homely to produce liquid hydrocarbons from mixture of syngas, carbon monoxide gas and hydrogen using metal and cobalt catalysts. The liquid hydrocarbon mentioned here is referred to the paraffin. Normally right in the first place the Fischer-Tropsch process is a series of gasification process of feedstock, to convert the biomass into the biogas that can be utilized to become liquid hydrocarbons, the green diesel.Let us adjudge a look at the gasification of biomass to syngas. The biomass may undergo low temperature gasification (800 grand piano C) to produce product gas which later on converted to bio-syngas by means of reforming and tar cracking steps. On the other hand, the product gas (CO, H2, CH4, CxHy) may be used to reach electricity. When the organic material inside the biomass burned-over, it may undergo complete combustion to produce carbon dioxide and water, or it may undergo partial combustion to carbon monoxide and hydrogen. What we need for the feeds of the Fischer-Tropsch process is the carbon monoxide and hydrogen and it can be achieved by control the amount of oxygen during combustion process (gasification). Several reactions are used to control the H2/CO ratio. Most important one is water gas shift reactions, in which the water is reacted with carbon monoxide to produce sources of hydrogen that requisite in the Fischer-Tropsch process. The chemical reaction of the Fischer-Tropsch process is shown as belowhttp//www.fischer-tropsch.org/primary_d ocuments/presentations/acs2001_chicago/slide03.gifFigure 1.2(1) Fischer-Tropsch Process 1For the Fischer-Tropsch reception, it is normally operated with temperature range of 150 300C. juicyer temperature will have high rate of conversion but also lead to the production of methane. Thus, the temperature is unceasingly maintained at low to middle temperature in order to take a breather yield of the green diesel. On the other hand, the pinch of the process is ranging from one to several tens atmospheric oblige. Higher tweet will help the reaction faster but also required more costs of operations such as high pressure equipment. We also need to know that too high pressure also can cause the metal or cobalt catalysts that used in the reaction to deactivate due to coke formation. A variety of catalysts can be used for the process such as iron, ruthenium and cobalt, depending on the aims of the operations.Figure 1.2(2) A open concept on Fischer-Tropsch ReactionGreen Chemistry and SustainabilityIn term of green chemistry, the use of renewable feedstock such as biomass is a sustainable way to overcome the depletion of crude oil. Biomass can be easily obtained from animal fats, agricultural wastes, soybean, woods, etc. The green diesel produced is im elanratelow sulfur content and the properties of the green diesel produced is very chemically similar with petrodiesel but better than it. The emission of the hazardous pollutant such as carbon dioxide, nitrogen dioxide is also 60-70% lesser. overly that, the product off-gas produced from the process can be used in twain ways1) addition recovery process to recover the chemicals from the byproducts and export them to other company, or 2) generate electricity which is sufficient to supply for some operations in within the plants.Environmental ImpactFischer-Tropsch process basically produces ultra clean green diesel which help in reduce the environmental issue such as global warming, greenhouse effect by reduce the emission of carbon dioxide and nitrogen oxide. It seems to be a great potential of alternatives to the non-renewable energy resources, the crude oil.The side products here are truly airy products and also heavy products like waxes which also have high market demand and can be exported out along with the green diesel.Flexibility of exertionThe production line is actually not only produce green diesel but also heavy products like waxes and also gasoline. By adjusting the operation condition, we may adjust the need to upgrade the production of desired productsThere are two favored nuclear reactor types which can be chosen depends on the operator Multitubular fixed retire reactor with internal cooling and also slurry bubble column reactor with internal cooling tubes.The process not only limited to the oil as feedstock but also may use the renewable feedstock such as biomass and animal fats.Energy ConsumptionThe energy consumption of this technology is mostly depends on the gasific ation process whereby it consumed 60-70% of the energy of the whole plant.For high temperature mode (HTFT), the direct temperature is between 300 and 350C while operating pressure can be ranging from one to several tens of atmospheric pressure.On the other hand, for low temperature mode (LTFT), the operating temperature is between 200 and 240 C with operating pressure of 1 to 10atm.AdvantagesNo nitrogenous, sulfur compounds formed during the reactionHigh cetane number can be obtained (75 90% higher than that required for petrochemical derived diesel fuel)Carbon neutral processProducts off-gas can be used to generate electricity which enough for the operation of the plant.DisadvantagesFT process is very complex in its reaction mechanism and several studies need to be fill out to maximize the productivity of green diesel from the process life-size number of species involved in the reaction and extra care is needed in the plant designThe present catalyst is not good enough to maximi ze the yield of the green dieselExtra process needed to convert the waxes formed from the FT process into green diesel (which mean extra cost)The cost of green diesel produced from the process may be more expensive than the diesel produced from the crude oilTable 1.2 (1) Key Components of Fischer-Tropsch Reaction1.2.2 Production of green diesel via Thermal Depolymerisation ProcessThermal depolymerisation (TDP) is an industrial process that able to break put down and convert various type of biomass or other carbon-containing material into a bio-oil product that is then refined into a petrodiesel-like fuel. Thermal depolymerisation involves a depolymerisation process using hydrous pyrolysis for the reduction of complex organic materials (usually waste products of various sorts, often biomass and plastic) into light crude oil. The process is found to be similar to the natural geological processes thought to be involved in the production of fossil fuels. Long chain polymers of hydroge n, oxygen, and carbon decompose into short-chain petroleum hydrocarbons with a maximum length of around 18 carbons under the application of modifying system and pressure. 1 The list of TDP suitable feedstocks are extensive and flexible, including waste plastic, tires, wood pulp, medical checkup waste, and rather unsavoury byproducts such as turkey offal and sewerage sludge.ever-changing World Technologies ( centner) are currently utilizing this method to process slaughterhouse waste and other carbon containing solid waste to create a fuel that can meet the standards of both ASTM D396 and ASTM D975. 2cusersdelldesktopdesigntdtcp.gifFigure 1.2(3) Thermal depolymerisation process to produce renewable diesel.In the method used by CWT, the water improves the inciteing process and contributes hydrogen to the reactions. The feedstock material is first break down into dwarfish chunks, and mixed with water (if it is dry). Then it is fed into a pressure vessel reaction chamber, heated to around 250 C at eonian volume (similar principal to a pressure cooker). Steam naturally raises the pressure to 4 MPa (near the point of saturated water) and is held for approximately 15 minutes to heat the mixture completely. After this, the pressure is rapidly released to flash off most of the water content in the feedstock, resulting a mixture of crude hydrocarbons and solid minerals. The minerals are later removed, and the hydrocarbons are channel to a second-stage reactor to heat up to 500 C in order to further prisonbreak down the longer hydrocarbon chains. The hydrocarbons are then sorted by fragmental distillation, in a process similar to conventional oil refining.CWT claims that 15 to 20% of feedstock energy is used to provide energy for the plant. The be energy is available in the converted product. Working with turkey offal as the feedstock, the process proved to have yield efficiencies of approximately 85% in other words, the energy contained in the end products of t he process is 85% of the energy contained in the inputs to the process (most notably the energy content of the feedstock, but also including electricity for pumps and natural gas or woodgas for heating).The process breaks down or so all materials that are fed into it. TDP even efficiently breaks down many types of hazardous materials, such as poisons and difficult-to-destroy biological agents such as prions. The light hydrocarbons that are produced by TDP can be used fuel sources, filters and fertilizers. It can be used a s a substitute for combust and also in quelling the alarming rise of carbon dioxide ingress in the air. CO2 is one of the chief greenhouse gases that are answerable for global warming.Green Chemistry and SustainabilityThe best part of using thermal depolymerisation (TDP) is that, it can break down substances such as plastic which takes long time to decompose. By using TDP, renewable diesel can be produce from plastic, not only save up waste to be buried, but al so getting useful green diesel out of unwanted waste.Methane in the feedstock is recovered and burned to heat the water, or burned in a combined heat and power plant to betray back electricity to the power gridEnvironmental Impact electric discharge of foul odors and unpleasant smell to the surrounding area of operating factory, causing nausea and uncomfortable feeling to resident nearbyFlexibility of OperationExtensive and flexible choice of feedstocks (waste plastic, tires, wood pulp, medical waste, and unsavory byproducts such as turkey offal and sewerage sludge)Energy ConsumptionRequire high energy consumption. High energy input requirements to produce green diesel made it not favorable among industry.Safety Factor and Waste chargeMethane gas produce can be treated by hot to heat up water to produce electricity.The process not only cleans up wastes but also generate new sources of energy.AdvantagesAble to break down strong chemical bonds of organic poison, making huge benefits to ecosystem balance.safely deal on heavy metals by converting them into stable oxides of their original ionised forms.Recycling the energy content of organic products while retaining the water content. (avoid drying while producing liquid fuel that separates from water in thermal depolymerisation, energy saving).The enormous bulk of waste content can be utilized to produce green diesel. Not only make good use of all the non-bio-degradable waste but also help in producing useful oil. 3The light hydrocarbons produced can be used fuel sources, filters and fertilizers.DisadvantagesOnly long molecular chains compound can be broken into shorter ones, so small molecules such as carbon dioxide or methane cannot be converted to oilIf taking biomass as the feedstock, most of the biomass is already being used as animal feed or fertilizers and so are not authentically available in plenty for TDPHigh processing costs, low yield, slag of yield, high energy input requirements making the proc ess not practicable and viable for large scale production.Table 1.2(2) Key Components of Thermal Depolymerisation Reaction1.2.3 Production of green diesel via Hydrotreating ProcessProduction of renewable energy is expanding at rapid pace worldwide. This phenomenon gives increasing petroleum prices, government formula and commitment in reducing greenhouse gases. In future, renewable dependent could be increasing as a new technology in producing high quality of renewable energy was invented. These new renewable diesel should be compatible to substitute conventional diesel for transportation. One of the available production processes of green diesel is hydrotreating

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