Choice of method

The general approach for calculating CO2 emissions from titanium dioxide production is the same irrespective of the product because the emissions are based on the quantity of reducing agent or carbothermal input. The choice of a good practice method depends on national circumstances as shown in the decision tree in Figure 3.6. Process emissions of carbon dioxide in TiO2 production take place primarily as a result of anode carbon oxidisation in the production of titanium slag, coal oxidisation in the process of producing synthetic rutile using the Becher process, and petroleum coke oxidisation in the process of producing rutile TiO2 via the chloride route.

Methods are classified according to the extent of plant-level data that are available.

TIER 1 METHOD

The Tier 1 method uses a default emission factor per unit of output multiplied by activity data obtained from national statistics. The basic equation for estimating CO2 emissions is:

Equation 3.12

CO2 emissions from titanium slag, synthetic rutile and rutile TlO2 production -

Tier 1

Where:

EC02 = emissions of CO2, tonnes

ADi = production of titanium slag, synthetic rutile or rutile TiO2 (product i), tonnes

EFi = CO2 emissions per unit of production of titanium slag, synthetic rutile or rutile TiO2 (product i), tonnes CO2/tonne product

TIER 2 METHOD

Emissions can be calculated from the consumption of the reducing agent for electrode carbon (titanium slag), and coal (synthetic rutile) in the Becher process, and the carbothermal input (petroleum coke) for rutile TiO2 from the chloride rout process. The Tier 2 method uses plant-level data on the quantities of reducing agent and carbothermal input to derive emissions as follows:

Equation 3.13

CO2 emissions from titanium slag, synthetic rutile and rutile TlO2 production -

Tier 2

Where:

ECO2 = emissions of CO2, kg

ADi = amount of reducing agent or carbothermal input i, GJ

CCFj = carbon content factor of reducing agent or carbothermal input i, kg C/GJ

COFj = carbon oxidation factor for reducing agent or carbothermal input i, fraction

To achieve the highest accuracy, good practice is to apply Equation 3.13 at the plant-level with all data inputs obtained from plant operators.

Where plant-level information is not available, good practice provides default CO2 emission factors for synthetic rutile and rutile TiO2 as shown in Table 3.9. A default factor for titanium slag is not available because of the small number of plants.

Box 3.6

Double counting

In order to avoid double counting, the quantities of electrode carbon, coal used as a reductant, and petroleum coke used in the chloride route process, must be subtracted from the quantity reported under energy and non-energy use in the Energy Sector.

Was this article helpful?

0 0
Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

Get My Free Ebook


Post a comment