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INTERNATIONAL MARITIME ORGANIZATION
SUB-COMMITTEE ON DANGEROUS GOODS, SOLID CARGOES AND CONTAINERS 14th session Agenda item 4
DSC 14/4 19 June 2009 Original: ENGLISH
AMENDMENTS TO THE IMSBC CODE, INCLUDING EVALUATION OF
PROPERTIES OF SOLID BULK CARGOES
Report on data, information and experiences on high moisture (up to 12%) content DRI(C) (by-product fines)
Submitted by the Bolivarian Republic of Venezuela and Trinidad and Tobago
Executive summary: This docement contains a report on the data, information and experiences discussed and analysed by the Bolivarian Republic of Venezuela and Trinidad and Tobago for further exploring the effects of high-mositure content DRI under inert conditions.
Strategic direction: 5.2 High-level action: 5.2.3 Planned output: - Action to be taken: Paragraph 6 Related documents: DSC 12/4/1; DSC 12/4/2; DSC 13/4/8; DSC 13/INF.11;
DSC 13/WP.1; MSC 85/26, paragraph 13.6 and DSC 14/INF.3 Background 1 It is recalled that at the discussions held during DSC 13, the delegation of Venezuela (Bolivarian Republic of) drew the attention of the Sub-Committee to paragraphs 13, 14 and 15 of the report of the working group (document DSC 13/WP.1) which stated that the main difficulty identified in drafting the schedule for inerting DRI Fines, which normally have a moisture content of up to 12%, was that no information was available on the form on how this wet cargo would behave under inert conditions. 2 In this sense, the working group accepted the proposal made by the delegations of Venezuela (Bolivarian Republic of) and Trinidad and Tobago to coordinate data, information and experiences through a voluntary correspondence group, in order to submit, to DSC 14, a document with a draft proposal for a DSC circular based on document DSC 12/4/1 submitted by Venezuela and in accordance with section 1.5 of the IMSBC Code. Venezuela (Bolivarian Republic of) will coordinate this joint effort under the chairmanship of Dr. Oscar Dam (firstname.lastname@example.org).
DSC 14/4 - 2 -
3 The main issues raised during the DSC 13 were the definition of DRI(C) (by-product fines) as a new cargo, besides its physical and chemical characteristics and moisture content of less than 0.3%, and whether or not DRI(C) high moisture cargo shall be carried under either mechanical ventilation or inert conditions. 4 During the meetings of DSC 11, DSC 12 and DSC 13, the following issues were discussed on the mechanical ventilation issue, which are the most relevant ones regarding the cargo:
.1 the porous character of the DRI(C) (by-product fines) cargo; .2 if mechanical ventilation was used, fresh wet and salty air will come into the
holds and the possibility of the fresh air to circulate through the porous cargo; .3 the possibility of triggering the iron re-oxidation and in consequence of the self
heating of the cargo and the Hydrogen release; and .4 the assessment of whether the hydrogen release rate of the cargo or the hydrogen
gas accumulation in the holds are the real hazard for the safe transport of the cargo.
5 The joint report produced by Venezuela (Bolivarian Republic of) and Trinidad and Tobago is set out in the annex to this document. Action requested of the Sub-Committee 6 The Sub-Committee is invited to note the information provided and take action as appropriate.
REPORT ON DATA, INFORMATION AND EXPERIENCES OF HIGH-MOISTURE CONTENT IN DRI FINES
Background 1 This report contains new technical information for:
.1 DRI(C) shipments conducted by Trinidad and Tobago, and Venezuela (Bolivarian Republic of) with mechanical ventilation (May 2005 up to March 2009); total tonnage, number of shipments, moisture content (greater than 0.3%), temperature, grain size (below 12 mm), bulk density, etc.;
.2 DRI Fines shipments destination: geographical area, %, voyage-day; .3 Safety index: 104 shipments carried safely under mechanical ventilation; and .4 Results of high moisture (up to 12% moisture) DRI(C) (by-product fines)
laboratory, pilot and shipments monitoring. 2 In order to solve the main issues presented during DSC 11, DSC 12 and DSC 13, several new tonne-scale tests were carried out by means of Test Drums and Test Tanks aiming to assess the following:
.1 the porous character of the DRI(C) (by-product fines) with moisture content over 0.3% and up to 12%; and
.2 the effect of inerting on this cargo.
3 One of the Drum Tests consisted in the measurement of the pressure drop measurement when allowing the flow of nitrogen gas through the DRI(C) (by-product fines) bed inside a 55-gallon capacity drum. 4 The other tests in drums (55-gall-cap.), one, and in a tank (4.3 m3), another, the following parameters were monitored: temperature of the DRI(C) (by-product fines) bed, the composition of the gases including Hydrogen, Oxygen and Nitrogen in percent volume. 5 All test details were presented in documents DSC 14/INF.3.
DSC 14/4 ANNEX Page 2
DRI(C) fines (by-product fines) characterization 6 The materials tested were DRI(C) fines (by-product fines) obtained from the processing and handling of DRI(A) and DRI (B). The characteristics of both materials are shown in Table I.
Tested DRI(C) DRI(C) (by-product fines) Characteristics from DRI(A) from DRI(B) Metallic iron 1-75% 1-75% Grain size up to 12 mm up to 12 mm Moisture content >0.3 - 12% >0.3 - 12% Aging minimum 30 days minimum 30 days Bulk density (Kg/m3) 1850-3300 1850-3300 Stowage Factor 0.3-0.54 0.3-0.54 Total Iron 64-90 62-90 Carbon 0.2-2.0 0.2-2.5 Phosphorus 0.07-0.1 0.03-0.1 Sulphur 0.01-0.03 0.01-0.03 Total Gangue 4.5-6.0 4.5-6.5 Typical grain size: >12 mm 6% max 6% max >6.35 mm 10-20% 10-20%
DSC 14/4 ANNEX
.5 temperature condition monitoring; and
.6 Hydrogen release rate in closed drum with some level of natural ventilation. 8.2 The results of the Drum Tests were as follows: 8.2.1 Test I
.1 The DRI(C) sample (Mexico Blend) had the following physical characteristics:
Moisture content: 7 % Bulk density: 2,550 kg/m3 Open porosity: 30% max.
.2 Sealed environment
.1 The sample was placed in an open drum and then sealed. After about 15 minutes the gas contained in the drum was analysed. It showed oxygen level below 2% without introduction of any external gases. The LEL at this point was 0.
.2 This low Oxygen content showed that the DRI(C) has the capability to
rapidly consume the oxygen from the environment to produce an inert atmosphere once system is sealed properly. The reactions taking place here is re-oxidation of metallic iron. This is confirmed through temperature profile of tests.
.3 The highest hydrogen evolution rate was 0.00052 lt/Kg.Hr at first,
averaged out to 0.00012 lt/Kg.Hr over 45-hour period and then went practically to zero. The reduction in hydrogen evolution after rate went to zero was most likely due to sampling which would remove hydrogen from the environment and also allow some but very little circulation of gases (mechanical ventilation effect).
.4 The results can be seen on Figure 1.
MV AHMSA DRI(C) Barrel Test Gas Trends 2009
NuIron - Trinidad
5-Apr 7-Apr 9-Apr 11-Apr 13-Apr 15-Apr 17-Apr 19-Apr 21-Apr 23-Apr 25-Apr 27-Apr
LEL (%) O2 (vol %)
TOTAL Fe (%)
Start 80.48 36.62 2.73 6.91 Natural WaterEnd 81.03 39.32 2.77 3.25
Inerting with N2
DSC 14/4 ANNEX Page 4
.3 Natural venting
.1 The top valve on drum test was opened for a period of approximately one hour with no driving force. The Oxygen came up to 4% and Hydrogen LEL went to zero. The valve was then left open and we moved to the inerting stage.
.1 Even though labelled inerting in graph 1 above, the inerting only
occurred for a period of about 15 minutes maximum. The Oxygen was brought back down to less than 1% Oxygen in the drum and then the top valve was closed making the system sealed again. Inerting had an effect of allowing the forward reaction to proceed. However it was at a much slower rate.
.2 The rate of H2 at this point after inerting was calculated
at 0.000093 lt/Kg.Hr. The cycling of results is most likely due to sampling. However the LEL was always showing an upward trend indicating if left for an extended period without testing the LEL would have accumulated.
.3 The material quality specs did not show much change. However
the moisture content before and after test showed a decrease of about 50%. This is not due to inerting since only 15 minutes of nitrogen was introduced. The fact that the drum was sealed resulted in a very humid environment and sampling and natural ventilation together with inerting provided the drive to remove the moisture from the containment. Other drum tests with longer inerting periods exceeding 1 hour each day did not show similar drop in moisture %.
8.2.2 Test II
.1 The DRI(C) sample (China Blend) had the follow