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PIECE Program for North American Mobility In Higher Education MODULE 14. “Life Cycle Assessment (LCA)” 4 steps of LCA, approaches, software, databases,

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1 PIECE Program for North American Mobility In Higher Education MODULE 14. “Life Cycle Assessment (LCA)” 4 steps of LCA, approaches, software, databases, subjectivity, sensitivity analysis, application to a classic example.

2 PIECENAMP Module 14 – Life Cycle Assessment 2 Tier III Open-ended problem

3 PIECENAMP Module 14 – Life Cycle Assessment 3 What are the prerequisites for this tier? It is further assumed that students already have an introductory- level background in Life Cycle Assessment (LCA) (from Tier I and Tier II) and the basic knowledge in petrochemical processes, such as would normally be part of any undergraduate engineering curriculum. Prerequisites for tier III

4 PIECENAMP Module 14 – Life Cycle Assessment 4 What is the purpose of this module? Open-Ended Design Problem. Is comprised of an open- ended problem to solve real-life application of LCA to the oil and gas sector. The global aim of that problem is to quantify the total environmental benefits and drawback of a process. Statement of intent

5 PIECENAMP Module 14 – Life Cycle Assessment 5 Spath and Mann. (2001) ”Life Cycle Assessment of Hydrogen Production via Natural Gas Steam Reforming“. National Renewable Energy Laboratory. Spath and Mann. (2001) ”Life Cycle Assessment of Hydrogen Production via Natural Gas Steam Reforming“. National Renewable Energy Laboratory. Spath and Mann. (1999) “Life Cycle Assessment of Coal-fired Power Production”. National Renewable Energy Laboratory. Spath and Mann. (1999) “Life Cycle Assessment of Coal-fired Power Production”. National Renewable Energy Laboratory. Mann and Spath. (1997) “Life Cycle Assessment of Biomass Gasification Combined-Cycle System”. National Renewable Energy Laboratory. Mann and Spath. (1997) “Life Cycle Assessment of Biomass Gasification Combined-Cycle System”. National Renewable Energy Laboratory. Rojey A., Minkkinen A., Arlie J.P. and Lebas E. “Combined Production of Hydrogen, Clean Power and Quality Fuels”. Institut Français du Pétrole (IFP). Rojey A., Minkkinen A., Arlie J.P. and Lebas E. “Combined Production of Hydrogen, Clean Power and Quality Fuels”. Institut Français du Pétrole (IFP). References

6 PIECENAMP Module 14 – Life Cycle Assessment 6 D. Gray, G. Tomlinson, “Opportunities For Petroleum Coke Gasification Under Tighter Sulfur Limits For Transportation Fuels,” Presented at the Gasification Technologies Conference, San Francisco, California, October 8–11, 2000 D. Gray, G. Tomlinson, “Opportunities For Petroleum Coke Gasification Under Tighter Sulfur Limits For Transportation Fuels,” Presented at the Gasification Technologies Conference, San Francisco, California, October 8–11, 2000 H. Baumann, A.M. Tillman(2004). ‘’The hitch Hicker’s Guide to LCA. An orientation in life cycle assessment methodology and application’’. Studentlitteratur AB. Lund, Sweden H. Baumann, A.M. Tillman(2004). ‘’The hitch Hicker’s Guide to LCA. An orientation in life cycle assessment methodology and application’’. Studentlitteratur AB. Lund, Sweden The Environmental Foundation Bellona :http://www.bellona.no/en/energy The Environmental Foundation Bellona : University of Newbrunswick (Canada) (Petroleum and Natural Gas Processing): University of Newbrunswick (Canada) (Petroleum and Natural Gas Processing): References

7 PIECENAMP Module 14 – Life Cycle Assessment 7 Tier III is broken in six parts: Description of the context: Hydrogen production via natural gas steam reformingDescription of the context: Hydrogen production via natural gas steam reforming Problem statementProblem statement Statement of the intentStatement of the intent Report StructureReport Structure RecommendationsRecommendations IndexIndex Unlike the previous two sections, this section does not have a quiz. The student must interpret the results of the above work and elaborate a succinct project report ( pages). Tier III: Content

8 PIECENAMP Module 14 – Life Cycle Assessment 8 Metric units of measure are used. Therefore, material consumption is reported in units based on the gram (e.g., kilogram or metric tonne), energy consumption based on the joule (e.g., kilojoule or megajoule), and distance based on the meter (e.g., meter). When it can contribute to the understanding of the analysis, the English system equivalent is stated in parenthesis. The metric units used for each parameter are given below, with the corresponding conversion to English units. Mass:kilogram (kg) = pounds Metric tonne (T) = ton (t) Distance: Meter (m) = 6200 mile = 3281 feet Area: hectare (ha) = 10,000 m2 = 2.47 acres Volume: cubic meter (m 3 ) = gallons normal cubic meters (Nm 3 ) = standard cubic feet (scf) at a standard temperature & pressure of 15.6°C (60°F) and kPa (14.7 psi), respectively Tier III: Units of measure

9 PIECENAMP Module 14 – Life Cycle Assessment 9 Pressure: kilopascals (kPa) = pounds per square inch Energy:kilojoule (kJ) = 1,000 Joules (J) = Btu Gigajoule (GJ) = MMBtu (million Btu) Terajoule (Tj) = 1.0 x 10 9 Joules (J) kilowatt-hour (kWh) = 3,414.7 Btu Gigawatt-hour (GWh) = 3.4 x 109 Btu Power: megawatt (MW) = 1 x 106 J/s Temperature:°C = (°F - 32)/1.8 Hydrogen Equivalents: 1 kg H 2 = scf gas = Nm 3 gas Tier III: Units of measure

10 PIECENAMP Module 14 – Life Cycle Assessment 10 Btu - British thermal units CO2-equivalence- Expression of the GWP in terms of CO2 for the following three components CO2, CH4, N2O, based on IPCC weighting factors EIA - Energy Information Administration GWP - global warming potential HHV - higher heating value HTS - high temperature shift IPCC- Intergovernmental Panel on Climate Change kWh - kilowatt-hour (denotes energy) LCA - life cycle assessment LHV - lower heating value LTS - low temperature shift MMSFCD - million standard cubic feet per day MW - megawatt (denotes power) N2O - nitrous oxide Nm3 - normal cubic meters NMHCs - non-methane hydrocarbons NOx - nitrogen oxides, excluding nitrous oxide (N2O) NREL - National Renewable Energy Laboratory PSA - pressure swing adsorption SMR - steam methane reforming SOx - sulfur oxides, including the most common form of airborne sulfur, SO2 Stressor - A term that collectively defines emissions, resource consumption, and energy use; a substance or activity that results in a change to the natural environment Stressor category - A group of stressors that defines possible impacts wt% - percentage by weight Tier III: Abbreviations and Terms

11 PIECENAMP Module 14 – Life Cycle Assessment 11 1.Description of the context: Hydrogen production via natural gas steam reforming Description of the context: Hydrogen production via natural gas steam reformingDescription of the context: Hydrogen production via natural gas steam reforming 2.Problem statement Problem statementProblem statement 3.Statement of the intent Statement of the intentStatement of the intent a.System boundaries System boundariesSystem boundaries b.Major assumptions Major assumptionsMajor assumptions c.Data Data 4.Report Structure Report StructureReport Structure 5.Recommandations Recommandations 6.Index Index Tier III: Outline

12 PIECENAMP Module 14 – Life Cycle Assessment 12 1.D escription of the context: Hydrogen production via natural gas steam reforming Tier III: Outline

13 PIECENAMP Module 14 – Life Cycle Assessment 13 1.Description of the context: Hydrogen production via natural gas steam reforming 1.1. Hydrogen (H 2 ) HydrogenHydrogen is used in a number of industrial applications, with today’s largest consumers being ammonia production facilities (40.3 %), oil refineries (37.3%), and methanol production plants (10.0%). Because such large quantities of hydrogen are required in these instances, the hydrogen is generally produced by the consumer, and the most common method is steam reforming of natural gas. The figure below shows a simplified flowsheet of the process utilised in this context for hydrogen production. steam reforming of natural gas. Hydrogensteam reforming of natural gas.

14 PIECENAMP Module 14 – Life Cycle Assessment 14 1.Description of the context: Hydrogen production via natural gas steam reforming 1.2. The process Hydrogen can be produced from natural gas, oil or coal. Synthesis gas production is a key step, as it gives access to a wide range of options. Synthesis gas which is formed mainly by a mixture of CO and H2 is obtained either by steam-reforming, in the case of natural gas or by partial oxidation. Steam methane reforming is the most common and least expensive method of producing hydrogen. About half of the world's hydrogen is produced from SMR (Gaudernack, 1998). The process can be used also with other light hydrocarbon feedstocks, such as ethane and naphtha. The process is endothermic and synthesis gas is typically produced in a tubular reformer furnace. natural gasSynthesis gas SMRnatural gasSynthesis gas SMR

15 PIECENAMP Module 14 – Life Cycle Assessment 15 1.Description of the context: Hydrogen production via natural gas steam reforming 1.Description of the context: Hydrogen production via natural gas steam reforming Inlet temperatures are within the range °C and the product gas leaves the reformer at °C, depending on the applications (Rostrup-Nielsen, 1993). The desulphurized feedstock is mixed with process steam and reacted over a nickel based catalyst contained in high alloy steel tubes. Although the plant requires some stream for the reforming and shift reactions, the highly exothermic reactions results in an excess amount of steam produced by the plant. Due to the high operating temperature in the reformer, the reformer effluent contains about vol % CO (dry basis). A high-temperature shift (HTS) operating at an inlet temperature of 343 to 371°C makes possible to convert about 80 to 90% of the CO. This step uses a catalyst which is typically composed of copper oxide-zinc oxide on alumina. A Pressure Swing Adsorption unit (PSA) is used for removing CO and other contaminants present with hydrogen. Pressure Swing Adsorption unit (PSA)Pressure Swing Adsorption unit (PSA)

16 PIECENAMP Module 14 – Life Cycle Assessment 16 1.Description of the context: Hydrogen production via natural gas steam reforming 1.Description of the context: Hydrogen production via natural gas steam reforming If the CO2 which is present typically at the level of 15-20% has to be recovered, it may be more appropriate to use a specific step for separating CO2 from hydrogen by solvent scrubbing. An amine solvent is typically used for such a separation step. The hydrogen thus obtained, can be exported. Refining is presently the main consumer of hydrogen. It can be used also in a combined cycle for generating electricity. Such a scheme provides therefore an attractive option for producing electricity, without emitting CO2. Synthesis gas produced during the initial step, can also be used for producing liquid hydrocarbon fuels, through Fischer-Tropsch synthesis. Thus, it is possible to transform any fossil fuel or biomass into hydrogen, electricity and liquid fuels.

17 PIECENAMP Module 14 – Life Cycle Assessment 17 1.D D eeee ssss cccc rrrr iiii pppp tttt iiii oooo nnnn o o o o ffff t t t t hhhh eeee c c c c oooo nnnn tttt eeee xxxx tttt :::: H H H H yyyy dddd rrrr oooo gggg eeee nnnn p p p p rrrr oooo dddd uuuu cccc tttt iiii oooo nnnn v v v v iiii aaaa n n n n aaaa tttt uuuu rrrr aaaa llll g g g g aaaa ssss s s s s tttt eeee aaaa mmmm r r r r eeee ffff oooo rrrr mmmm iiii nnnn gggg 2.P roblem statement Tier III: Outline

18 PIECENAMP Module 14 – Life Cycle Assessment 18 2.Problem Statement An oil & gas plant seeks to modernize by looking at 3 process options: improving the environmental aspects, improving the performance of some units of production to maximize the hydrogen production and finaly to install a better system of electronic control of the process. Your are the process engineer in this firm. Your boss, the plant manager, wants you to do a study on the the total environmental aspects (quantification and analysis) of producing 48 MMscfd of hydrogen via natural gas steam reforming for the intern study. In recognition of the fact that upstream processes required for the operation of the Steam Methane Reforming (SMR) plant also produce pollutant and consume energy and natural resources. The data colletion and validation have already been done by another engineer.

19 PIECENAMP Module 14 – Life Cycle Assessment 19 1.D D eeee ssss cccc rrrr iiii pppp tttt iiii oooo nnnn o o o o ffff t t t t hhhh eeee c c c c oooo nnnn tttt eeee xxxx tttt :::: H H H H yyyy dddd rrrr oooo gggg eeee nnnn p p p p rrrr oooo dddd uuuu cccc tttt iiii oooo nnnn v v v v iiii aaaa n n n n aaaa tttt uuuu rrrr aaaa llll g g g g aaaa ssss s s s s tttt eeee aaaa mmmm r r r r eeee ffff oooo rrrr mmmm iiii nnnn gggg 2.P P rrrr oooo bbbb llll eeee mmmm s s s s tttt aaaa tttt eeee mmmm eeee nnnn tttt 3.S tatement of the intent Tier III: Outline

20 PIECENAMP Module 14 – Life Cycle Assessment 20 1.Description of the context: Hydrogen production via natural gas steam reforming Description of the context: Hydrogen production via natural gas steam reformingDescription of the context: Hydrogen production via natural gas steam reforming 2.Problem statement Problem statementProblem statement 3.Statement of the intent a.System boundaries Tier III: Outline

21 PIECENAMP Module 14 – Life Cycle Assessment 21 3.Statement of the intent 3.1. System boundaries This LCA should be performed in a cradle-to-grave manner, for this reason, natural gas production and distribution, as well as electricity generation, were included in the system boundaries. The steps associated with obtaining the natural gas feedstock are drilling/extraction, processing, and pipeline transport. The next figure shows the System Boundaries for Hydrogen Production via Natural Gas Steam Reforming.

22 PIECENAMP Module 14 – Life Cycle Assessment 22 3.Statement of the intent 3.1. System boundaries For this study, the plant life was set at 20 years with 2 years of construction. In year one, the hydrogen plant begins to operate; plant construction takes place in the two years prior to this (years negative two and negative one). In year one the hydrogen plant is assumed to operate only 45% (50% of 90%) of the time due to start-up activities. In years one through 19, normal plant operation occurs, with a 90% capacity factor. During the last year the hydrogen plant is decommissioned. Therefore, the hydrogen plant will be in operation 67.5% (75% of 90%) of the last year.

23 PIECENAMP Module 14 – Life Cycle Assessment 23 1.Description of the context: Hydrogen production via natural gas steam reforming Description of the context: Hydrogen production via natural gas steam reformingDescription of the context: Hydrogen production via natural gas steam reforming 2.Problem statement Problem statementProblem statement 3.Statement of the intent a.System boundaries System boundariesSystem boundaries b.Major assumptions Tier III: Outline

24 PIECENAMP Module 14 – Life Cycle Assessment 24 3.Statement of the intent 3.2. Major assumptions A pretreatment on the natural gas is necessary to avoid emposoinment of the catalysts with the sulphur. The H2S is removed in a hydrogenation reactor and then in a ZnO bed. After pretreatment, the natural gas and 2.6 MPa steam are fed to the steam reformer. The resulting synthesis gas is then fed to high temperature shift (HTS) and LTS reactors where the water gas shift reaction converts 92% of the CO into H2. Hydrogen Plant Block Flow Diagram

25 PIECENAMP Module 14 – Life Cycle Assessment 25 3.Statement of the intent The hydrogen is purified (to 99.9% mol.) using a pressure swing adsorption (PSA) unit. The reformer is fueled primarily by the PSA off-gas, but a small amount of natural gas is used to supply the balance of the reformer duty. The PSA off-gas is comprised of CO2 (47.06 mol%), H2 (24.26 mol%), CH4 (19.59 mol%), CO (7.8 mol%), N2 (0.55 mol%), and some water vapor. The steam reforming process produces 4.8 MPa steam. Electricity is purchased from the grid to operate the pumps and compressors. The hydrogen plant energy efficiency is defined as the total energy produced by hydrogen plant divided by the total energy into the plant, determines by the following formula: The base case of this analysis assumed that 1.4% of the natural gas that is produced is lost to the atmosphere due to fugitive emissions.

26 PIECENAMP Module 14 – Life Cycle Assessment 26 1.Description of the context: Hydrogen production via natural gas steam reforming Description of the context: Hydrogen production via natural gas steam reformingDescription of the context: Hydrogen production via natural gas steam reforming 2.Problem statement Problem statementProblem statement 3.Statement of the intent a.System boundaries b.Major assumptions Major assumptionsMajor assumptions c.Data  Construction material Requirement Tier III: Outline

27 PIECENAMP Module 14 – Life Cycle Assessment 27 3.Statement of the intent Construction material requirement: Construction Plant Materials Requirements and pipeline The next table list materials requirements used for the plant in this study. A sensitivity analysis was performed how changing these numbers would affect the results. MaterialAmount required (Mg) Concrete Steel Aluminum Iron Hydrogen Plant Material Requirement (Base Case)

28 PIECENAMP Module 14 – Life Cycle Assessment 28 3.Statement of the intent To move the natural gas from the oil or gas wells to the hydrogen plant, we use pipelines. Because the main pipeline is shared by many users, only a portion of the material requirement was allocated for the natural gas combined-cycle plant. For this analysis, the total length of pipeline transport for the natural gas combined-cycle plant is assumed to be 425 km, it was sized so that the total pressure drop in the pipe is of 0.05 psi/100 feet (0.001 MPa/100 meters). The pipe has a diameter of 31 inches assuming a wall thickness of 1 inch. The steel used for the pipe construction has a density of 7700 kg/m3.

29 PIECENAMP Module 14 – Life Cycle Assessment 29 3.Statement of the intent Air Emissions due to materials’ construction Air emissiong of emission/Kg of H2 produced Benzene(C6H6) 1.4 CO CO 5.46 CH NO N2O NMHCs Particulate SO The construction of materials requirements also produce a lot of air emissions. Because of lack of data, we will suppose that those constructions emit ton of particulate/hectare of the mill/month of activity. You can suppose that NMHCs = 50% mass. benzene + 50% mass. Toluene. Air emissions due to the plant construction

30 PIECENAMP Module 14 – Life Cycle Assessment 30 1.Description of the context: Hydrogen production via natural gas steam reforming Description of the context: Hydrogen production via natural gas steam reformingDescription of the context: Hydrogen production via natural gas steam reforming 2.Problem statement Problem statementProblem statement 3.Statement of the intent a.System boundaries b.Major assumptions c.Data  Construction material Requirement Construction material Requirement Construction material Requirement  Natural gas composition and lost Tier III: Outline

31 PIECENAMP Module 14 – Life Cycle Assessment 31 3.Statement of the intent Natural gas composition and loss While natural gas is generally though of as methane, about 5-25% of the volume is comprised of ethane, propane, butane, hydrogen sulfide, and inerts (nitrogen, CO2 and helium). The relative amounts of these components can vary greatly depending on the location of the wellhead. The next table gives the composition of the natural gas feedstock use in this analysis, as well as typical pipeline and wellhead compositions. The composition used in this study (first column) assumes that the natural gas has undergo a pretreatment before entering the desulphurization reactor. The natural gas feedstock contains up to 7 ppmv total sulfur, max. 5 ppmv in the form of hydrogen sulphide (H2S) and max. 2 ppmv organic sulfur as mercaptane.

32 PIECENAMP Module 14 – Life Cycle Assessment 32 3.Statement of the intent Natural Gas Composition Natural gas feedstock used in analysis Typical range of wellhead components (mol%) ComponentMol % (dry)Low valueHigh value Methane (CH 4 ) Ethane (C 2 H 6 ) Propane (C 3 H 8 ) Nitrogen (N 2 ) Carbon Dioxide (CO 2 ) Iso-butane (C 4 H 10 ) N-butane (C 4 H 10 ) Pentanes (C 5 + ) N-pentane N- +(C6) Hydrogen (H2)

33 PIECENAMP Module 14 – Life Cycle Assessment 33 3.Statement of the intent In extracting, process, transmitting, storing and distributing natural gas, some is lost to the atmosphere. Over the past two decades, the natural gas industry and others have tried to better quantify the losses. There is a general consensus that fugitive emissions are the largest source, accounting for about 38% of the total, and that nearly 90% of the fugitive emissions are a result of leaking compressor components. The second largest source of methane emissions comes from pneumatic control devices, accounting for approximately 20% of the total losses. The majority of the pneumatic losses happen during the extraction step. Engine exhaust is the third largest source of methane emissions due to incomplete combustion in reciprocating engines and turbines used in moving the natural gas through the pipeline. These three sources make up nearly 75 % of the overall estimated methane emissions. The remaining 25% come from sources such as dehydrators, purging of transmissions/storage equipment, and meter and pressure regulating stations in distribution lines.

34 PIECENAMP Module 14 – Life Cycle Assessment 34 1.Description of the context: Hydrogen production via natural gas steam reforming Description of the context: Hydrogen production via natural gas steam reformingDescription of the context: Hydrogen production via natural gas steam reforming 2.Problem statement Problem statementProblem statement 3.Statement of the intent a.System boundaries System boundariesSystem boundaries b.Major assumptions Major assumptionsMajor assumptions c.Data  Construction material Requirement Construction material Requirement Construction material Requirement  Natural gas composition and lost Natural gas composition and lost Natural gas composition and lost  Production and distribution of electricity Tier III: Outline

35 PIECENAMP Module 14 – Life Cycle Assessment 35 3.Statement of the intent production and distribution of electricity Electricity is purchased from the grid to operate the pumps and compressors. The production was assumed to be the generation mix of coal, lignite (hard coal), oil and fuel/natural gas. The process consume approx. 129,104 Mj/day. Each fuel provide respectively 3%, 2%, 72% and 23% of the total energy needed by the process. The stressors associated with this mix should also determined in a cradle-to-grave manner. The table below presents the quantity (in kg) of air emissions for each fossil fuel used for electricity production. Those data relate to a functional unit of 1 Tj net electricity delivered from the power plant. CoalFuel gasOilLignite CO CO NOx SO Particulates N2O

36 PIECENAMP Module 14 – Life Cycle Assessment 36 1.Description of the context: Hydrogen production via natural gas steam reforming Description of the context: Hydrogen production via natural gas steam reformingDescription of the context: Hydrogen production via natural gas steam reforming 2.Problem statement Problem statementProblem statement 3.Statement of the intent a.System boundaries System boundariesSystem boundaries b.Major assumptions Major assumptionsMajor assumptions c.Data  Construction material Requirement Construction material Requirement Construction material Requirement  Natural gas composition and lost Natural gas composition and lost Natural gas composition and lost  Production and distribution of electricity Production and distribution of electricity Production and distribution of electricity  H 2 Production plant Tier III: Outline

37 PIECENAMP Module 14 – Life Cycle Assessment 37 3.Statement of the intent H 2 Production plant Hydrogenation and Desulphurization As the reformer catalyst is sensitive to poisoning from sulfur, sulfur in the natural gasis processed in a Hydrogenation Reactor. Sulfur is totaly converted to hydrogen sulfide in this Hydrogenation reactor and will be absorbed on the zinc oxide by conversion of ZnO to ZnS in the desulphurization reactor. Natural gas leaving the reactor will have a residual sulfur content of less than 0.2 ppmv. The total adsorption capacity of the desulphurization catalyst, based on total 7 ppmv sulfur in the feedstock will be for minimum 2 years of uninterrupted operation. A small amount of hydrogen, which is recycled from the product stream, is used in the Hydrogenation step to adjust the pressure in the reactor. The table below gives the caractheristics of the inflow of the hydrogenation reactor. The flow in Kg/hKmol/h Natural gas feedstock Hydrogen (H2)5728 Inflows to the hydrogenation reactor

38 PIECENAMP Module 14 – Life Cycle Assessment 38 3.Statement of the intent H 2 Production plant Steam reforming In the steam reforming, the mixture of desulphurized natural gas and process steam (3358 kmol/h at 2.6 MPa (380 psi)) is reformed under application or external heat. The principle chemical reactions taking place in the steam reformer are as follows: Steam reforming Water-gas Shift reaction (which is highly exothermic) The effluent contains besides the products CO2 and residual CH4 and H2O. The reformed gas leaves the SR at 810ºC and approx. 25 kg/cm2 abs.. All reactions take place simultaneously at about 560ºC. However, the reaction as a whole is endothermic. Those reactions take place over a nickel-based catalyst. The waste heat contained in the furnace flue gas is utilized for superheating of the reformer feedstock, generating of medium pressure steam, superheating of the medium pressure steam and preheating of the combustion air. Those gases leave the reformer at approx. 1000ºC.

39 PIECENAMP Module 14 – Life Cycle Assessment 39 3.Statement of the intent Components% mol. CO2 6.2 H N C C2 0 C3 0 i-C4 0 N-C4 0 i-C5 0 N-C5 0 N-C6 0 H2O CO 7.08 The reformed gas composition

40 PIECENAMP Module 14 – Life Cycle Assessment 40 3.Statement of the intent The combustion air given is based on 5% excess air and enters the burner at 380ºC and approx. 1.2 kg/cm2, at a rate of kg/h. It is composed of 20.4% mol. O2, 76.77% mol. N2 and 2.83% of H2O. Waste heat is recovered from the flue gas as well as from the reformed gas to preheat and superheat process streams and for steam production. The natural gas utilized as fuel for the burner contains 5 ppmv of H2S and 2 ppmv of mercaptane and has the following composition and characteristics: Molar mass (kg/mol)18.38 Flow in kmol/h26.4 Pression (kg/cm2)2 Temperature ( º C) 20

41 PIECENAMP Module 14 – Life Cycle Assessment 41 3.Statement of the intent Components% mol. CO20.8 N21.02 C186.1 C210.5 C31.18 i-C40.11 N-C40.17 i-C50.04 N-C50.04 N-C60.04 The table below presents the composition of the flue gas at the outlet of the burners. Components% mol. CO O21.05 N H2O19.38 Molar composition of of the natural gas used in the burner

42 PIECENAMP Module 14 – Life Cycle Assessment 42 3.Statement of the intent H 2 Production plant High Temperature Shift (HTS) The carbon monoxide, which is produced in the steam reformer, is converted by means of water vapor on a catalyst in a HTS reactor to hydrogen and carbon dioxide, according to the following reaction: This reaction is highly exothermic, which leads to temperature rise of about 50ºC. The CO-content at the outlet of the Shift reactor is less than 2 mol-%. Subsequently the shifted gas is cooled down in different exchangers to approx. 36ºC. Process condensate is separated in multiple liquid-gas separators. The gas is then routed to the PSA Unit.

43 PIECENAMP Module 14 – Life Cycle Assessment 43 3.Statement of the intent H 2 Production plant Separators The outflow gas from the HTS passes by different exchangers and liquid-gas separators. At the outlet of the last separator, we obtain two flows. On flow of 481 kg/h of liquid water at 35ºC and a gaseous flow principally composed of hydrogen (H2) and carbon dioxide (CO2) at a rate of kg/h (3945 kmol/h). The table bellow gives the molar composition of this gaseous flow: Component% mol. CO CO2.8 H272.7 H2O0.27 N20.24 CH47.07 Molar composition of the gaseous outflow of the last separator before the PSA unit

44 PIECENAMP Module 14 – Life Cycle Assessment 44 3.Statement of the intent H 2 Production plant Pressure Swing absorption (PSA) For final purification a Pressure Swing Adsorption process is used. The reminder of undesired components are removed from the bulk of hydrogen by means of adsorption on molecular sieves using a PSA. The purification of hydrogen is based on selective adsorption of gas components such as CH4, CO, CO2, N2 and H2O. Hydrogen does not absorb and leaves the PSA unit as a product gas with high purity. Subsequently the pure hydrogen product is compressed and a small amount is recycled to upstream of the Hydrogenation Reactor. The adsorbed gases in the PSA are released and routed as off-gases to the off gas which ensures a stable and constant supply of fuel gas to the burners of the reformer. The Hydrogen (H2) obtained from the PSA has a 99% molar purity. It leaves the PSA Unit at 40ºC at 5149 kg/h (2525 kmol/h).

45 PIECENAMP Module 14 – Life Cycle Assessment 45 3.Statement of the intent H 2 Production plant Steam Generation System Waste heat from the process is utilized for steam generation. As the main source of energy, the sensible heat of the reformed gas downstream Steam Reformer is used for steam production in Reformed Gas Waste Heat Boiler. An other source of heat for steam generation is the waste heat of the flue gas leaving the steam reformer. Here additional steam is produced in Flue Gas Waste Heat Boiler.

46 PIECENAMP Module 14 – Life Cycle Assessment 46 3.Statement of the intent H 2 Production plant Shut down The process is shuted down for 24 hours every 2 years to change the catalysts. During start-up of the process or PSA Unit failure, we use a burners’ fuel (for the SR) composed in majority of natural gas (12.88 the mole rate of the natural gas used in normal operation case) completed with Raffinery fuel. The mole ratio of thoses two fuels is 8.5.

47 PIECENAMP Module 14 – Life Cycle Assessment 47 1.D D eeee ssss cccc rrrr iiii pppp tttt iiii oooo nnnn o o o o ffff t t t t hhhh eeee c c c c oooo nnnn tttt eeee xxxx tttt :::: H H H H yyyy dddd rrrr oooo gggg eeee nnnn p p p p rrrr oooo dddd uuuu cccc tttt iiii oooo nnnn v v v v iiii aaaa n n n n aaaa tttt uuuu rrrr aaaa llll g g g g aaaa ssss s s s s tttt eeee aaaa mmmm r r r r eeee ffff oooo rrrr mmmm iiii nnnn gggg 2.P P rrrr oooo bbbb llll eeee mmmm s s s s tttt aaaa tttt eeee mmmm eeee nnnn tttt 3.S S tttt aaaa tttt eeee mmmm eeee nnnn tttt o o o o ffff t t t t hhhh eeee i i i i nnnn tttt eeee nnnn tttt a.S S yyyy ssss tttt eeee mmmm b b b b oooo uuuu nnnn dddd aaaa rrrr iiii eeee ssss b.M M aaaa jjjj oooo rrrr a a a a ssss ssss uuuu mmmm pppp tttt iiii oooo nnnn ssss c.D D aaaa tttt aaaa 4.R eport structure Tier III: Outline

48 PIECENAMP Module 14 – Life Cycle Assessment 48 4.Report structure 4.1. Questions for discussion 1- Quantify the environmental loads - resource use and pollutant air emissions - of the system. 2- Make the results more environmentally relevant by translating the emissions using environmental themes method. Identify and evaluate the environmental impacts of the process by making an impact assessment by calculating the total impact. The index list is in the Index towards the end of the problem.

49 PIECENAMP Module 14 – Life Cycle Assessment 49 4.Report structure 4.1. Questions for discussion 3- Make a sensitivity study and identify the most important parameters toward their influence on the results of this study. 4- Examine the net emission of greenhouse gases, as well as the major environmental consequences. greenhouse gasesgreenhouse gases 5- Substitutions scenarios: What possible improvements on the system could we do ? 7- Make a cost-benefit Analysis, typically involves an economic ROI study. 8- Since Risk is another matter not dealt with in LCA, we won’t ask you about it but you should write a short paragraph about the Ecological Risk Assessment (ERA) related to this process.

50 PIECENAMP Module 14 – Life Cycle Assessment 50 4.Report structure 4.2. Suggestion for Report Table of Contents 1.Executive summury 2.Introduction 3.Objectives 4.Summury of results 5.Sensitivity Analysis 6.Impact Assessment 7.Impovement Opportunities 8.Conclusions

51 PIECENAMP Module 14 – Life Cycle Assessment 51 1.D D eeee ssss cccc rrrr iiii pppp tttt iiii oooo nnnn o o o o ffff t t t t hhhh eeee c c c c oooo nnnn tttt eeee xxxx tttt :::: H H H H yyyy dddd rrrr oooo gggg eeee nnnn p p p p rrrr oooo dddd uuuu cccc tttt iiii oooo nnnn v v v v iiii aaaa n n n n aaaa tttt uuuu rrrr aaaa llll g g g g aaaa ssss s s s s tttt eeee aaaa mmmm r r r r eeee ffff oooo rrrr mmmm iiii nnnn gggg 2.P P rrrr oooo bbbb llll eeee mmmm s s s s tttt aaaa tttt eeee mmmm eeee nnnn tttt 3.S S tttt aaaa tttt eeee mmmm eeee nnnn tttt o o o o ffff t t t t hhhh eeee i i i i nnnn tttt eeee nnnn tttt a.S S yyyy ssss tttt eeee mmmm b b b b oooo uuuu nnnn dddd aaaa rrrr iiii eeee ssss b.M M aaaa jjjj oooo rrrr a a a a ssss ssss uuuu mmmm pppp tttt iiii oooo nnnn ssss c.D D aaaa tttt aaaa 4.R R eeee pppp oooo rrrr tttt s s s s tttt rrrr uuuu cccc tttt uuuu rrrr eeee 5.R ecommendations Tier III: Outline

52 PIECENAMP Module 14 – Life Cycle Assessment Recommendations 1.When reporting the final results of your work it is important to thoroughly describe the methodology used in this analysis. The report should explicitly define the system analyzed and the boundaries that were set. 2.All assumptions or decisions made in performing the work should be clearly explained and reported along side the final results of this project. 3.The results should not be oversimplified solely for the purposes of presentation. 4.All the environnemental data needed to do this work are given towards the end of the problem (in the Index). 5.You should respect the international standards for LCA (ISO ) when performing the different steps of the analyze.

53 PIECENAMP Module 14 – Life Cycle Assessment 53 End of Tier III This is the end of Module 14. Please submit your report to your professor for grading.This is the end of Module 14. Please submit your report to your professor for grading. We are always interested in suggestions on how to improve the course. You may contact us at are always interested in suggestions on how to improve the course. You may contact us at

54 PIECENAMP Module 14 – Life Cycle Assessment 54 INDEX

55 PIECENAMP Module 14 – Life Cycle Assessment 55 To meet the needs of this study, categorization and less-is-better approaches have been taken. The next table summarizes the stressors categories and main stressors from the natural gas steam reforming, hydrogen production system. Impact Categories SubstanceStatic reserve life (years) Natural gas kg Sb eq /m 3. Hard coal kg Sb eq /kg Soft coal kg Sb eq /kg Fossil energy4.81 x kg Sb eq /Mj 1. Depletion of abiotic resources Depletion equivalents for abiotic resources, expressed relative to antimony (Sb) and based on ultimate reserves.

56 PIECENAMP Module 14 – Life Cycle Assessment 56 Impact Categories 2. Global warming Trace gasGWP 100 years (kg CO 2 eqv /kg) CO 2 1 CH 4 25 N2ON2O310 NO Acidification SubstanceAP (g SO 2 eqv /g) SO 2 1 NO x 0.7 Global warning potentials for 100 years expressed in relative to CO2 Generic acidification equivalents expressed relative to SO2 (CML/NOH 1992; in CML 2002)

57 PIECENAMP Module 14 – Life Cycle Assessment 57 Impact Categories 4. Photochemical ozone creation potential (contribution to smog) SubstanceHigh NOx POCPs (kg ethylene/kg) CO NO Methane Ethane Propane N-butane N-pentane N-C Benzene Toluene Photochemical ozone creation potentials (POCPs) for high NOx background concentrations expressed relative to ethylene (CML 2002)

58 PIECENAMP Module 14 – Life Cycle Assessment 58 Impact Categories 5. Human toxicity Human toxicity potentiels, HTPinf, for infinite horizon and global scale. The indicators are expressed relative to 1,4-dichlorobenzene 6. Eutrophication Generic eutrophication equivalents for emissions to air, water and soil. Indicators are expressed relative to PO3-4 (CML/NOH 1992; CML 2002). SubstanceHTP for emissions to air NO SO Benzene1900 Toluene0.33 Substance(g PO 3- 4 /g) PO H 3 PO P3.06 NH NH N0.42

59 PIECENAMP Module 14 – Life Cycle Assessment 59 Impact Categories Impacts Associated with Stressor Categories

60 PIECENAMP Module 14 – Life Cycle Assessment 60 Economic data The reactor The catalyst Description Quantity (m 3 ) Price Desulphurisation reactor Zinc Oxide Desulphurisation Catalyst (ZnODs) Zinc Oxide based catalyst having specific physical and textural properties blended with suitable binders in the form of pellets US/lb SR Nickel Based A nickel based catalyst on alpha alumina carrier or calcium aluminate compound in the form of rings/high geometric surface rings US/L HTS Copper Oxide-Zinc Oxide on Alumina An iron chrome and copper promoted iron chrome based catalyst US/L Hydrogenation reactor Catalysts Due to lack of data, we suppose that all these catalysts have the same density than water.

61 PIECENAMP Module 14 – Life Cycle Assessment 61 Economic data EquipmentDescription/UtilityQuantityVessel For water 1 Compressor Centrifugal; Emotor; Isentropic; Combustion Air Fan 3 Compressor Centrifugal; Emotor; Isentropic; Flue gas Fan 2 Compressor H2 compressor, Reciprocating, Isentropic 2 Drum Steam condensate 1 Drum Tank and deaerator 1 Drum For flare gas 1 Drum Gas separator 1 Drum Shifted gas separator 1 Drum 1 Drum For fuel gas 1 Shell- tube HE Feed preheater 1 Equipment

62 PIECENAMP Module 14 – Life Cycle Assessment 62 Economic data Shell- tube HE BFW-Preheater1 Reformed gas final cooler 1 Plate HE Blow down cooler 1 Air Cooler Reformed gas air cooler 1 Static Mixer At the feed 1 Pumps Centrifugal; team turbine 2 Pumps Flare condensate; Drum pump 2 Reactor Hydrogenation with jacket 1 Reactor Desulphurization, jacket 1 ReactorHTS1 Steamturbine For BFW pump; back-pressure turbine 1 Steamturbine Turbine for Fluegas Fan; back-pressure turbine 2 TOTAL TOTAL25 Also consider that you need 3 feeds for the alimentation and the effluents and that you have 2 purges. Consider also that we use a Straightline depreciation during 10 years with a resale price of 0$.

63 PIECENAMP Module 14 – Life Cycle Assessment 63 Economic data H 2 price Gray and Tomlinson (2000) proposed equations to calculate the hydrogen costs based on the prices of fuels in the world-wide market, in these equations it is assumed that the value of hydrogen is equal to the cost of producing it from reformation. Based on this the cost of sale of hydrogen is given by: CSH = 0.45CGN Where: Where: CSH = Cost of Hydrogen Duty ($/MPCSD) CGN = Cost of Natural Gas ($/MMBtu) Gray y Tomlinson (2000) also established a simple equation to estimate the cost of the natural gas in function of the price of petroleum in the world, which is: CGN = 0.13PPM Where: Where: PPM = Price of the Petrol in the World ($/BBL) Most of the hydrogen produced at the present time is consumed in its site of production. When it is sold in the market, to its production cost is added the cost of liquefying it and of transporting it.

64 PIECENAMP Module 14 – Life Cycle Assessment 64 Economic data Electricity cost In order to calculate the cost of the electricity used to produce hydrogen, Gray and Tomlinson (2000) assumed that the value of the electricity is determined by the cost of producing it with a advanced plant of combined cycle of natural gas. It was assumed that the cost of capital of this type of plants is of $494/kw and an amount of specified energy of BTU/KW. Based on these estimations the sale price required of the electricity it is given by the following equation: CEPH = CGN Where: CEPH = Cost of electricity for produce hydrogen ($/KWh)...the end.

65 PIECENAMP Module 14 – Life Cycle Assessment 65 Complementary information Hydrogen Energy Hydrogen is the simplest element. It’s also the most plentiful element in the universe. Despite its simplicity and abundance, hydrogen doesn’t occur naturally as a gas on the Earth- it’s always combined with other elements. Hydrogen is produced from sources such as natural gas, coal, gasoline, methanol or biomass through application of heat; from bacteria or algae Through photosynthesis; or by using electricity or sunlight into hydrogen and oxygen. Hydrogen is high in energy, yet an engine that burns pure hydrogen produces almost no pollution. Hydrogen fuel cells power the shuttle’s electrical system, producing a clean byproduct-pure water, which the crew drinks.

66 PIECENAMP Module 14 – Life Cycle Assessment 66 Complementary information Hydrogen Energy A fuel cell combines hydrogen and oxygen to produce electricity, heat and water. Fuel cells are often compared to batteries. Both convert the energy produced by a chemical reaction into usable electric power. However, the fuel cell will produce electricity as long as fuel (hydrogen) is supplied, never losing its charge. In the future, hydrogen could also join electricity as an important energy carrier. Some experts think that hydrogen will from the basic energy infrastructure that will power future socie replacing today’s natural gas, oil, coal and electricity infrastructures. They see a new hydrogen econor our current energy economies, although that vision probably won’t happen until far in the future.

67 PIECENAMP Module 14 – Life Cycle Assessment 67 Complementary information Steam Reforming of Natural Gas Steam reforming of natural gas is currently the least expensive method of producing hydrogen, and used for about half of the world’s production of hydrogen. Steam, at a temperature of 700 – 1100 o C is mixed with methane gas is a reactor with a catalyst at 3 – 25 bar pressure. Thirty percent more natural gas in required for this process, but new process are constantly being developed to increase the rate of production. It is possible to increase the efficiency to over 85% with a economic profit at higher thermal integration. A large steam reformer which produces tons of hydrogen a year can supply roughly one million fuel cell cars with an annual average driving range of km. There are two types of steam reformers for small-scale hydrogen production: Conventional reduced-scale reformers and specially designed reformers for fuel cells. The latter operates under lower pressure and temperatures than conventional reformers and is more compact.

68 PIECENAMP Module 14 – Life Cycle Assessment 68 Complementary information Steam Reforming of Natural Gas The formula for this process is: CH4 + H2O -> CO + 3 H2 It is usually followed by the shift reaction: CO + H2O -> CO2 + H2 1 mol methane -> 4 mol hydrogen The percentage of hydrogen to water is 50% In steam reforming of natural gas, 7.05 kg CO2 are produced per kg hydrogen.

69 PIECENAMP Module 14 – Life Cycle Assessment 69 Complementary information Greenhouse gases Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases: Carbon dioxide is released to the atmosphere when solid waste, fossil fuels (oil, natural gas, and coal), and wood and wood products are burned. Methane is emitted during the production and transportation of coal, natural gas and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills and the rising of livestock. Nitrous oxide is emitted during agricultural and industrial activities, as well as during combustion of solid waste and fossil fuels.

70 PIECENAMP Module 14 – Life Cycle Assessment 70 Complementary information Greenhouse gases Very powerful greenhouse gases that are not naturally occurring include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6), which are generated in a variety of industrial processes. Each greenhouse gas differs in its ability to absorb heat in the atmosphere. HFCs and PFCS are the most heat-absorbent. Methane traps over 21 times heat per molecule than carbon dioxide, and nitrous oxide absorbs 270 times more heat per molecule than carbon dioxide. Often, estimates of greenhouse gas emissions are presented in units of millions of metric tons of carbon equivalents (MMTCE), which weights each gas by its GWP value, or Global Warming Potential.

71 PIECENAMP Module 14 – Life Cycle Assessment 71 Complementary information Natural Gas Natural gas is a combustible, gaseous mixture of simple hydrocarbon compounds, usually found in deep underground reservoirs formed by porous rock. Natural gas is fossil fuel composed almost entirely of methane, but does contain small amounts of other gases, including ethane, propane, butane and pentane. The prevailing scientific theory id that natural gas was formed millions of years ago when plants and try sea animals were buried by sand and rock. Layers of mud, sand, rock and plant and animal matter continued to build up until the pressure and heat from the earth turned them into petroleum and natural gas.

72 PIECENAMP Module 14 – Life Cycle Assessment 72 Complementary information Steam Methane Reformer (SMR) Refineries have a voracious appetite for hydrogen. Depending on the refinery operations, it may necessary to have a hydrogen plant. In a hydrogen plant, hydrogen is produced by the reforming of a hydrocarbon feedstock with steam. The best feedstock for this is methane. Reformer. The reformer is basically a huge furnace that contains tubes filled with nickel catalyst. The feed is a mixture of steam and methane and the reaction in the reformer is carried out at 650 to 1000 o C and 600 psi. the primary reforming reaction is: CH4 + H2O -> 3H2 + CO CH4 + H2O -> 3H2 + CO However, some CO2 is also formed in the reformer. Typical yields in the reformer effluent are 75% H2, 15% CO and 10% CO2.

73 PIECENAMP Module 14 – Life Cycle Assessment 73 Complementary information Steam Methane Reformer (SMR) Shift Convert. The shift converter is designed to produce more hydrogen by reacting the CO from the reformer with more steam according to the following reaction: CO + H2O -> CO2 + H2 CO + H2O -> CO2 + H2 This is a classical reaction that you may have seen referred to as the “water gas shift”. It is carried out at 425 oC over an iron-oxide catalyst. Frequently, the shift convert consists of a high temperature and low temperature and low temperature section. The low temperatures section converts the remainder of the CO to CO2 by taking advantage of favorable equilibrium for this exothermic reaction. Amine Contactor. The CO2 is removed from the shift convert effluent by scrubbing in an amine contractor like that described in the section on Natural Gas Processing. The product of the Scrubber contains traces of CO and CO2 in a highly concentrated hydrogen stream.

74 PIECENAMP Module 14 – Life Cycle Assessment 74 Complementary information Steam Methane Reformer (SMR) Methanator. Even traces of CO and CO2 in the hydrogen product can poison the catalyst of downstream processes or build up in recycle streams. Therefore, the CO and CO2 must be converted to CH4 in the methanator according to: CO + 3H2 -> CH4 + H2O CO + 3H2 -> CH4 + H2O CO2 + 4H2 -> CH4 + 2H2O The effluent stream from the methanator is about 98% H2 and 2% CH4 and is ready to be used in processes where hydrogen is required.

75 PIECENAMP Module 14 – Life Cycle Assessment 75 Complementary information Synthesis gas A mixture of carbon dioxide, carbon monoxide and hydrogen formerly made by using water gas and reacting to with steam to enrich the portion of hydrogen for use in the synthesis of ammonia. The synthesis gas can be used for producing power and/or hydrogen, methanol, Fischer-Tropsch liquids, etc. In a gasification process, a feedstock is heated to very high temperatures (100 oC to 1500 oC) under pressure (20 bar to 85 bar) in the presence of controlled amounts of stream and pure oxygen. Two sets of reactions occur in the gasifier. CnHm + (n2)O2 -> nCO + (m/2)H2 CO2 + C -> 2CO CO2 + C -> 2CO C + H2O -> CO + H2 C + H2O -> CO + H2 CO + H2O -> CO2 + H2 CO + H2O -> CO2 + H2 In addition to CO, H2 and CO2, small amounts of CH4, HCL, HF, COS, NH3 and HCN are also formed. H2S is also formed with the amount dependent on the sulfur content of the feedstock.

76 PIECENAMP Module 14 – Life Cycle Assessment 76 Complementary information Pressure Swing Adsorption (PSA) Combined with our engineering upgrades, this field experience has enabled PSA units that are flexible and reliable. They have a high turndown ratio and can maintain both recovery and product purity by automatically adjusting cycle times. Absorbents are selected according to the nature of the impurities that need to be removed from the hydrogen-containing streams and their capacity to offer a long cycle life. PSA units can be designed to achieve up to % hydrogen purity. Hydrogen recovery can vary between 50% and over 95%. The result is a function of the purity of the incoming stream, off-gas pressure and recycling. Operating pressures range between 5 and 50 bar. Hydrogen is usually recovered with a minimal pressure loss of 1 bar.


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