Adding gas from biomass to the gas grid - SGC

More documents

Recommendations

Info

A second difference between coal and biomass is the reactivity. Biomass readily reacts with oxygenat temperatures starting at 600 °C. Coal needs at least 800 - 1200 °C to obtain a useful rate ofconversion. Biomass also readily hydrolyses with water. Pyrolysis of biomass can also beconducted at moderate temperatures.Newly designed biomass gasification plants have a modest size (5 - 50 ton/day) and applymoderate temperature and pressure processes. Pyrolysis and hydrogenation improve the quality ofthe syngas.Considering the addition of gas from biomass to the grid, most attention has to be given to smallscalehydro-pyrolysis gasifiers. The cleaning and upgrading of the rich syngas from these reactorsis much easier than the utilisation of the lean syngas from ‘classic’ gasification processes. A recentIGU publication [lit.7] shows that from new biomass and waste gasification plants fifty utilise classiccoal gasification processes and only seven utilise a pyrolysing reactor.page: 25
4 PIPELINE QUALITY GAS FROM BIOGAS4.1 INTRODUCTIONBiogas from anaerobic digestion consists primarily of methane (typically 60 - 70%) and carbondioxide. Other components can be oxygen and nitrogen, originating from air, sulphur compounds, inparticular hydrogen sulphide and water. In order to obtain pipeline quality gas the biogas must passtwo major processes:• A cleaning process, in which trace components harmful to the natural gas grid, appliances orend-users are removed.• An upgrading process, in which the calorific value, Wobbe index and other parameters areadjusted in order to meet the pipeline specifications.Furthermore, the gas must be odorised before it is added to the natural gas grid.The relevance and feasibility of the different types of cleaning and upgrading processes depends onthe specific biogas composition, which again is a result of the biomass feedstock and the digestionprocess. The two major steps are not always totally separated. Some membrane separationprocesses, e.g., do not only remove carbon dioxide from the methane, but also hydrogen sulphide.This chapter describes processes that are capable of upgrading the biogas to pipeline quality.However, in some cases the upgraded gas may not have to meet the pipeline specificationscompletely. The gas quality of the mixture of natural gas and upgraded gas downstream of the pointwhere the upgraded gas enters the gas grid is a function of:• The composition of the upgraded gas• The composition of the natural gas• The ratio between the flows of natural gas and upgraded gasIf e.g. the Wobbe index of the natural gas is somewhat higher than the minimum limit, the mixture ofnatural gas and upgraded gas can meet this specification even if the Wobbe index of the upgradedgas is lower than the limit. If lower qualities can be allowed as output from the upgrading process,the efficiency and methane yield of the upgrading process can be improved, and the investment andoperating costs can be reduced.If biogas is distributed in a closed biogas network or in a town gas network, only the cleaning ofbiogas is necessary. This option has been demonstrated in Sweden and Denmark. § 4.5 givessome details of this approach.page: 26
Page 1 and 2: Report SGC 118Adding gas from bioma
Page 3 and 4: CONTENTS1 INTRODUCTION 32 IMPORTANC
Page 5 and 6: 2 IMPORTANCE OF ADDING GAS FROM BIO
Page 7 and 8: Incentives by eco-labelingBy adding
Page 9 and 10: is mixed with coal in a combustor p
Page 11 and 12: Comparing efficiency data is a diff
Page 13 and 14: Figure 1: Energy flow diagram and i
Page 15 and 16: The product revenues are the most u
Page 17 and 18: 3.1.2 Survey of technologiesThis pa
Page 19 and 20: 3.1.3 Table of biogas compositionsD
Page 21 and 22: Aspect Unit ValueManure M 3 /day 6B
Page 23 and 24: Technologies for syngas upgradingTh
Page 25: CompositionProcesscalorific value M
Page 29 and 30: Removal of hydrogen sulphide with m
Page 31 and 32: Parameter Unit Process Plant exampl
Page 33 and 34: Parameter Unit Process valueCapacit
Page 35 and 36: 600.9500.840Wobbe index [MJ/m 3 n]R
Page 37 and 38: Figure 4 illustrates reported inves
Page 39 and 40: 4.3.4 Upgrading by absorption of ca
Page 41 and 42: Removal of carbon dioxide by water
Page 43 and 44: Selexol from the flash tank is depr
Page 45 and 46: poisonous and aggressive liquid wit
Page 47 and 48: Parameter Unit ProcessCapacity rang
Page 49 and 50: gas system is maintained by a contr
Page 51 and 52: In the gasification process the fir
Page 53 and 54: A catalytic process requires a feed
Page 55 and 56: In all countries gas in a distribut
Page 57 and 58: 6 SUPPLYING GAS FROM BIOMASS TO THE
Page 59 and 60: In Europe only two kinds of natural
Page 61 and 62: Component or quality Unit Limit or
Page 63 and 64: The directive thus also provides po
Page 65 and 66: Figure 13: Maximum range of permitt
Page 67 and 68: Figure 16: Wobbe index for differen
Page 69 and 70: 6.2.5 Discrepancies between standar
Page 71 and 72: 6.2.7 Description of national or de
Page 73 and 74: Figure 17:Arrangement of the contro
Page 75 and 76: Measurement methodDetection tubes f
Page 77 and 78:
Descriptioncalculation of propertie
Page 79 and 80:
The possibility of adding off-spec
Page 81 and 82:
Europe among countries relying on e
Page 83 and 84:
7.1.3 FinlandBiogas is mainly produ
Page 85 and 86:
Figure 18: Distribution of capacity
Page 87 and 88:
Calorific Availability Market price
Page 89 and 90:
Many landfills are equipped with ga
Page 91 and 92:
the type and volume of the respecti
Page 93 and 94:
7.2.4 FranceThere are currently no
Page 95 and 96:
7.2.7 SwedenBiogas as a fuel for ve
Page 97 and 98:
Policy on renewable energyThe gener
Page 99 and 100:
Danish energy policy is to contribu
Page 101 and 102:
Carbon dioxide taxApplication€/to
Page 103 and 104:
CHP FundThe CHP Fund is an incentiv
Page 105 and 106:
Taxation and incentivesFeed-in tari
Page 107 and 108:
Subsidies and fundingThere are seve
Page 109 and 110:
Figure 20:Impact of the energy tax
Page 111 and 112:
TargetsParallel with the target on
Page 113 and 114:
Sweden has no actual program dedica
Page 115 and 116:
Swedish energy taxesThe Swedish ene
Page 117 and 118:
8 CONCLUSIONS AND RECOMMENDATIONSCo
Page 119 and 120:
14 Upgrading Landfill Gas to Natura
Page 121 and 122:
46 ISO 15971: “Natural gas - Meas
Page 123 and 124:
APPENDIX 1:DefinitionsBiogasBiomass
Page 125 and 126:
fixed bed gasification: BIONEERProc
Page 127 and 128:
Final cooling is accomplished by me
Page 129 and 130:
used for direct drying applications
Page 131 and 132:
fluidised bed gasification:EISENMAN
Page 133 and 134:
fluidised bed gasification:SELTECpr
Page 135 and 136:
The Battelle biomass gasification p
Page 137 and 138:
Primary heat exchangerThe primary h
Page 139 and 140:
active coal filter and cooled. The
Page 141 and 142:
• Kärnten (Austria)pyrolysis:Pro
Page 143 and 144:
Quality Value UnitComponents• Car
show all

Adding gas from biomass to the gas grid - SGC

Create successful ePaper yourself

Delete template?

Save as template?