(BAT) Reference Document for the Production of Chlor-alkali ...

2.6.12.1 Purpose ...................................................................................................................55
2.6.12.2 Chemical reactions..................................................................................................57
2.6.12.3 Use and treatment of the produced bleach..............................................................58
2.7 Caustic processing production, storage and handling...............................................................59
2.8 Hydrogen processing production, storage and handling...........................................................61
2.9 Production of caustic potash.....................................................................................................62
3 CURRENT PRESENT EMISSION AND CONSUMPTION LEVELS ......................................63
3.1 Introduction ..............................................................................................................................63
3.2 Overall Overview of emission and consumption levels of all cell plants .................................64
3.3 Consumption levels of all cell plants Inputs in the production line ..........................................67
3.3.1 Sodium chloride/potassium chloride ..............................................................................67
3.3.2 Water ..............................................................................................................................67
3.3.3 Ancillary materials .........................................................................................................69
3.3.4 Energy ............................................................................................................................71
3.3.4.1 Overview ................................................................................................................71
3.3.4.2 Energy consumption for preparation and purification of raw materials .................72
3.3.4.3 Energy consumption for the electrolysis.................................................................72
3.3.4.3.1 General considerations....................................................................................72
3.3.4.3.2 Energy consumption of mercury cells ............................................................74
3.3.4.3.3 Energy consumption of diaphragm cells.........................................................75
3.3.4.3.4 Energy consumption of membrane cells.........................................................75
3.3.4.3.5 Comparison of electrolysis cells .....................................................................76
3.3.4.3.6 Production of caustic potash ...........................................................................77
3.3.4.4 Energy consumption for caustic soda concentration...............................................77
3.3.4.5 Energy consumption for auxiliary equipment.........................................................78
3.3.4.6 Comparison of the three cell techniques.................................................................78
3.4 Emissions and waste generation from all cell plants Emissions from auxiliary processes .......82
3.4.1 Emissions from the storage and handling of solids salt unloading and storage..............82
3.4.2 Emissions and waste generation from the brine circuit ..................................................82
3.4.2.1 Overview ................................................................................................................82
3.4.2.2 Emissions to air Air emissions................................................................................82
3.4.2.3 Emissions to water Water emissions.......................................................................83
3.4.2.3.1 Overview.........................................................................................................83
3.4.2.3.2 Sulphate ..........................................................................................................84
3.4.2.3.3 Chloride ..........................................................................................................85
3.4.2.3.4 Free oxidants...................................................................................................86
3.4.2.3.5 Chlorate and bromate......................................................................................88
3.4.2.3.6 Heavy metals Metals.......................................................................................90
3.4.2.3.7 Halogenated organic compounds Chlorinated hydrocarbons..........................92
3.4.2.3.8 Sulphite...........................................................................................................93
3.4.2.4 Generation of wastes...............................................................................................93
3.4.3 Emissions and waste generation from chlorine processing, gas production, cooling,
drying, liquefaction and storage and handling................................................................95
3.4.3.1 Overview ................................................................................................................95
3.4.3.2 Emissions to air Air emissions................................................................................95
3.4.3.2.1 Carbon dioxide................................................................................................95
3.4.3.2.2 Chlorine ..........................................................................................................95
3.4.3.2.3 Chlorine dioxide .............................................................................................97
3.4.3.2.4 Carbon tetrachloride .......................................................................................97
3.4.3.2.5 Refrigerants.....................................................................................................98
3.4.3.3 Emissions to water Water emissions.......................................................................98
3.4.3.4 Generation of wastes...............................................................................................98
3.4.3.4.1 Spent sulphuric acid from chlorine drying......................................................98
3.4.3.4.2 Carbon tetrachloride .......................................................................................99
3.4.3.4.3 Bleach .............................................................................................................99
3.4.4 Emissions and waste generation from sodium and potassium hydroxide processing...100
3.4.5 Emissions from hydrogen processing...........................................................................101
3.4.6 Emissions during other than normal operating conditions............................................101
3.4.6.1 Emissions during start-up and shutdown operations.............................................101
3.4.6.2 Emissions during malfunctions.............................................................................101
3.4.6.3 Emissions during accidents...................................................................................102
3.4.6.4 Emissions during decommissioning .....................................................................102
WORKING DRAFT IN PROGRESS
iv December 2011 TB/EIPPCB/CAK_Draft_1