Methods for delivery of carbon dioxide to a flowable concrete mix

摘要

Compositions and methods are provided for a system in which liquid carbon dioxide, or a mixture of liquid and gaseous carbon dioxide, is converted to solid carbon dioxide by exiting an orifice at a sufficient pressure drop, e.g., for delivery of carbon dioxide to a concrete mixture in a mixer.

主权项

1. A method of carbonating a flowable concrete mix comprising:
(i) delivering carbon dioxide to the concrete mix; wherein the carbon dioxide is delivered as a mixture of gaseous and solid carbon dioxide for at least part of the delivery time, and wherein the carbon dioxide is delivered by a method comprising:
a. delivering the carbon dioxide via a delivery line with diameter Dp to an orifice with diameter Do, and through the orifice, optionally also through a conduit attached to the orifice, to the concrete mix,b. supplying carbon dioxide to the delivery line by flowing pressurized gaseous carbon dioxide to the delivery line via a carbon dioxide gas line and/or flowing pressurized liquid carbon dioxide to the delivery line via a carbon dioxide liquid line, so that at least part of the carbon dioxide reaching the orifice during delivery of the carbon dioxide to the concrete mix is liquid carbon dioxide, so thatc. the carbon dioxide exits the orifice as a gas, a solid, or a mixture thereof, (ii) determining a total amount of carbon dioxide delivered to the concrete mix by a method comprising:
a. determining a pressure of the carbon dioxide, Pu, in the delivery line proximal to the orifice at a plurality of times,b. determining a first temperature of the carbon dioxide, T, in the delivery line proximal to the orifice at the plurality of times,c. determining a second temperature of the carbon dioxide, TD, as it exits the orifice at the plurality of times; wherein, for each time of the plurality of times, all of Pu, T, and TD are measured at the same time,d. determining from TD for each time whether the carbon dioxide in the delivery line when it reaches the orifice is 100% gas or 100% liquid, or a mix of gas and liquid,e. calculating an instantaneous flow rate for each time, wherein
1. when the carbon dioxide in the delivery line as it is delivered to the orifice for a time is 100% gas or 100% liquid, the flow rate is calculated from Dp, Do, Pu and T for that time, andwhen the carbon dioxide in the delivery line as it is delivered to the orifice for a time is a mixture of gas and liquid, the flow rate is calculated from Do, Pu, T, and TD for that time, andf. integrating the flow rates for the plurality of times to obtain a total amount of carbon dioxide delivered; and (iii) modulating the delivery of the carbon dioxide to the concrete mix based at least in part on the total amount of carbon dioxide delivered determined in step ii) f).