Equipment for conveying solid and gaseous carbon dioxide

Abstract

This document provides an apparatus for delivering solid and gaseous carbon dioxide, comprising: (i) a liquid carbon dioxide source including a tank containing liquid carbon dioxide; (ii) a first conduit including a proximal end operatively connected to the liquid carbon dioxide source and a distal end operatively connected to an orifice; (iii) a second conduit operatively connected to the orifice to guide a mixture of gaseous and solid carbon dioxide to a desired destination; and (iv) a third conduit operatively connected to the second conduit, wherein the third conduit includes a portion configured to sufficiently slow the flow of solid carbon dioxide through that portion of the third conduit to cause the solid carbon dioxide to agglomerate before exiting the third conduit through an opening. The apparatus is capable of delivering a precise dose of carbon dioxide at a desired solid-to-gas ratio under low-dose conditions and / or intermittent conditions.

Description

[0001] This application is a divisional application of Chinese national phase patent application No. 201980030698.2, which entered the Chinese national phase on November 6, 2020 from PCT application No. PCT / US2019 / 066407, with an international filing date of December 13, 2019, and an international application title of “Methods and Combination Structures for Delivering Carbon Dioxide”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Patent Application No. 62 / 779,020, filed December 13, 2018, which is incorporated by reference herein in its entirety. This application is related to U.S. Patent Application No. 15 / 650,524, filed July 14, 2017, and U.S. Patent Application No. 15 / 659,334, filed July 25, 2017, both of which are incorporated by reference herein. TECHNICAL FIELD

[0004] This application relates to the delivery of carbon dioxide, and in particular to devices for delivering solid and gaseous carbon dioxide. BACKGROUND

[0005] It is well known to use a snow cone to produce a mixture of gaseous and solid carbon dioxide from liquid carbon dioxide. Snow cones are typically used to deliver relatively large doses of carbon dioxide as solid carbon dioxide, and in general, it is not necessary or possible to achieve precise or reproducible doses of carbon dioxide from a snow cone in the desired ratio of solid to gaseous carbon dioxide, especially at low doses and / or under intermittent conditions. SUMMARY

[0006] In one aspect, provided herein are methods.

[0007] In certain embodiments, provided herein is a method for intermittently delivering a dose of carbon dioxide in solid and gaseous forms to a destination, the method comprising (i) passing liquid carbon dioxide from a source of liquid carbon dioxide to an orifice via a first conduit, wherein (a) the first conduit comprises a material capable of withstanding the temperature and pressure of the liquid carbon dioxide, and (b) the pressure drop through the orifice and the configuration of the orifice cause solid and gaseous carbon dioxide to be produced as the carbon dioxide exits the orifice; (ii) passing the solid and gaseous carbon dioxide through a second conduit, wherein the ratio of the length of the second conduit to the length of the first conduit is at least 1:1; and (iii) directing the carbon dioxide exiting the second conduit to a destination. In certain embodiments, the length, diameter, and material of the first conduit are such that, after a transition period, when the ambient temperature is less than 30°C, the liquid carbon dioxide entering the first conduit arrives at the orifice as at least 90% liquid carbon dioxide. In certain embodiments, the second conduit has a slip joint. In certain embodiments, the first conduit is not insulated. In certain embodiments, the method further comprises: directing the solid and gaseous carbon dioxide from the end of the second conduit into a third conduit, wherein the third conduit comprises a portion configured to sufficiently slow the flow of the carbon dioxide through the portion of the third conduit so that solid carbon dioxide agglomerates before it exits the third conduit through an opening. In certain embodiments, the portion of the third conduit configured to slow the flow of carbon dioxide is an enlarged portion compared to the second conduit. In certain embodiments, the ratio of the length of the third conduit to the length of the second conduit is less than 0.1:1. In certain embodiments, the third conduit has a length of between 1 and 10 feet. In certain embodiments, the third conduit has an inner diameter of between 1 inch and 3 inches. In certain embodiments, the ratio of the length of the second conduit to the length of the first conduit is at least 2:1. In certain embodiments, the first conduit has a length of less than 15 feet. In certain embodiments, the first conduit has an inner diameter of between 0.25 and 0.75 inches. In certain embodiments, the first conduit comprises an inner material of braided stainless steel. In certain embodiments, the second conduit has a length of at least 30 feet. In certain embodiments, the second conduit has an inner diameter of between 0.5 and 0.75 inches. In certain embodiments, the second conduit comprises an inner material of PTFE. In certain embodiments, the third conduit comprises a rigid material and is operably connected to a fourth conduit comprising a flexible material. In certain embodiments, the combined length of the third and fourth conduits is between 2 and 10 feet.In certain embodiments, the first conduit includes a valve for regulating the flow of carbon dioxide, wherein the method further comprises determining the pressure and temperature between the valve and the orifice, and determining the flow rate of the carbon dioxide based on the temperature and the pressure. In certain embodiments, the flow rate is determined by comparing the pressure and temperature to a set of calibration curves of flow rate at a plurality of temperatures and pressures. In certain embodiments, the destination to which the carbon dioxide is directed is within a mixer. In certain embodiments, the mixer is a concrete mixer. In certain embodiments, the carbon dioxide is directed to a location in the mixer where a wave of concrete is superimposed on the mixing concrete as the mixer is mixing the concrete mixture. In certain embodiments, the concrete mixer is a stationary mixer. In certain embodiments, the mixer is a transportable mixer. In certain embodiments, the mixer is a drum of a ready-mix truck. In certain embodiments, the total thermal capacity of the first and / or second conduit does not exceed the thermal capacity consumed by the first and / or second conduit to cool from the liquid carbon dioxide flowing through the conduit to the ambient temperature in less than 30 seconds. In certain embodiments, the orifice is such that solid and gaseous carbon dioxide exit the orifice in a mixture comprising at least 40% solid carbon dioxide. In certain embodiments, the conduit is directed to add carbon dioxide to a concrete mixer, and wherein cement is added to the mixer through a cement conduit comprising a first portion comprising a rigid chute connected to a second portion comprising a flexible sheath configured to allow a ready-mix truck to move a hopper on the ready-mix truck over the sheath such that the sheath is suspended into the hopper, allowing cement and other ingredients to fall through the sheath into a drum of the ready-mix truck, wherein the third conduit is positioned alongside the first portion of the cement conduit, and the fourth conduit is positioned to self-move and direct with the second portion of the cement conduit. In certain embodiments, aggregate is added to the mixer through an aggregate chute adjacent to the cement chute, and wherein a first portion of the third conduit is positioned to reduce contact with the aggregate as the aggregate exits the aggregate chute. In certain embodiments, the first portion of the third conduit extends to the bottom of the first portion of the cement chute, and the fourth conduit is attached to an end of the third conduit and extends from the end of the third conduit to the bottom of, or near the bottom of, a rubber sheath when the rubber sheath is positioned within the hopper of the ready-mix truck.In certain embodiments, the fourth conduit is generally positioned within x cm of the center of the rubber boot when the rubber boot is positioned to load concrete material into the drum of the ready-mix truck, wherein x = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, or 90 cm.

[0008] In another aspect, provided herein are apparatuses.

[0009] In certain embodiments, provided herein is an apparatus for delivering solid and gaseous carbon dioxide, the apparatus comprising (i) a source of liquid carbon dioxide; (ii) a first conduit, wherein the first conduit comprises a proximal end operably connected to the source of liquid carbon dioxide, and a distal end operably connected to an orifice, wherein the first conduit is configured to transfer liquid carbon dioxide under pressure to the orifice, and wherein the orifice opens to atmospheric pressure, or a pressure close to atmospheric, and is configured to convert the liquid carbon dioxide to a mixture of solid and gaseous carbon dioxide as the liquid carbon dioxide passes through the orifice; (iii) a second conduit operably connected to the orifice to direct the mixture of gaseous and solid carbon dioxide to a desired destination, wherein the second conduit has a slipstream, and wherein the ratio of the length of the first conduit to the length of the second conduit is less than 1 : 1. In certain embodiments, the ratio of the length of the first conduit to the length of the second conduit is less than 1 :2. In certain embodiments, the ratio of the length of the first conduit to the length of the second conduit is less than 1 :5. In certain embodiments, the length of the first conduit is less than 20 feet. In certain embodiments, the length of the first conduit is less than 15 feet. In certain embodiments, the length of the first conduit is less than 12 feet. In certain embodiments, the length of the first conduit is less than 5 feet. In certain embodiments, the first conduit comprises a valve before the orifice for regulating the flow of the liquid carbon dioxide. In certain embodiments, the apparatus further comprises a first pressure sensor between the valve and the orifice. In certain embodiments, the apparatus further comprises a second pressure sensor between the source of liquid carbon dioxide and the valve. In certain embodiments, the apparatus further comprises a third pressure sensor after the orifice. In certain embodiments, the apparatus further comprises a temperature sensor between the valve and the orifice. In certain embodiments, the apparatus further comprises a control system operably connected to the first pressure sensor and the temperature sensor. In certain embodiments, the controller receives a pressure from the first pressure sensor and a temperature from the temperature sensor, and calculates a flow rate of carbon dioxide in the system from the pressure and temperature. In certain embodiments, the controller calculates the flow rate based on a set of calibration curves for the apparatus. In certain embodiments, the set of calibration curves are generated with a calibration setup comprising: a source of liquid carbon dioxide; a first conduit; an orifice; a valve in the first conduit before the orifice; a pressure sensor between the valve and the orifice; and a temperature sensor between the valve and the orifice, wherein the material of the first conduit, the length and diameter of the first conduit, and the material and configuration of the orifice are the same as or similar to those of the apparatus.In certain embodiments, the set of calibration curves is generated by determining the flow of carbon dioxide at a plurality of temperatures as measured at the temperature sensor and a plurality of pressures as measured at the pressure sensor. In certain embodiments, the apparatus further comprises a third conduit operably attached to the second conduit, wherein the third conduit has a larger inner diameter than the second conduit, and wherein the diameter and length of the third conduit are configured to slow the flow of the gaseous and solid carbon dioxide and cause agglomeration of the solid carbon dioxide. In certain embodiments, the first conduit is not insulated.

[0010] In certain embodiments, provided herein is an apparatus for delivering low doses of solid and gaseous carbon dioxide in an intermittent manner of repeated doses of solid and gaseous carbon dioxide, the apparatus comprising (i) a source of liquid carbon dioxide; (ii) a first conduit, wherein the first conduit comprises a proximal end operably connected to the source of liquid carbon dioxide, and a distal end operably connected to an orifice, wherein the first conduit is configured to transfer liquid carbon dioxide under pressure to the orifice, and wherein the orifice is open to atmospheric pressure and configured to convert the liquid carbon dioxide to a mixture of solid and gaseous carbon dioxide as the liquid carbon dioxide passes through the orifice; (iii) a valve in the conduit between the source of carbon dioxide and the orifice for regulating the flow of liquid carbon dioxide; (iv) a heat source operably connected to a section of the conduit between the valve and the orifice, and operably connected to the orifice, wherein the heat source is configured to warm the conduit and orifice between doses to convert liquid or solid carbon dioxide to a gas that is vented through the orifice. In certain embodiments, the apparatus further comprises a heat sink operably connected to the heat source. In certain embodiments, the apparatus further comprises (v) a second conduit operably connected to the orifice to direct the mixture of gaseous and solid carbon dioxide to a desired destination. In certain embodiments, the second conduit has a slip joint. In certain embodiments, the ratio of the length of the first conduit to the length of the second conduit is less than 1 : 1.

[0011] In another aspect, provided herein is a system.

[0012] In certain embodiments, provided herein is a system for delivering solid and gaseous carbon dioxide in intermittent fashion at a dose of less than 60 pounds of carbon dioxide, wherein the time between doses is at least 5 minutes, wherein the system is configured to deliver repeated doses of carbon dioxide at an average ratio of solid to gaseous carbon dioxide of at least 1 : 1.5 in each dose, in less than 60 seconds per dose, at an ambient temperature of 35 °C or less. In certain embodiments, the system is configured to deliver repeated doses of carbon dioxide with a coefficient of variation of less than 10%. In certain embodiments, the system is configured to deliver repeated doses of carbon dioxide with a coefficient of variation of less than 5%. In certain embodiments, the system comprises a source of liquid carbon dioxide and a conduit from the source to a device configured to convert liquid carbon dioxide to solid and gaseous carbon dioxide, wherein the conduit need not be insulated. In certain embodiments, the conduit is not insulated. In certain embodiments, the system further comprises a second conduit connected to the device for converting the liquid carbon dioxide to solid and gaseous carbon dioxide, wherein the second conduit delivers the solid and gaseous carbon dioxide to a desired destination. In certain embodiments, the ratio of the length of the first conduit to the second conduit is less than 1 : 1.

[0013] incorporated by reference

[0014] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. BRIEF DESCRIPTION OF DRAWINGS

[0015] The novel features of the application are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present application will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the application are utilized, and the accompanying drawings of which:

[0016] Figure 1 A direct injection assembly for carbon dioxide is shown that does not require a gas line to keep the assembly free of dry ice between runs. DETAILED DESCRIPTION

[0017] The methods and assemblies of the present invention provide reproducible dosing of solid and gaseous carbon dioxide under intermittent conditions and at low dosages and short delivery times without the use of equipment and methods that would result in significant loss of carbon dioxide during the process. The methods and equipment as provided herein can allow very precise dosing, for example, a coefficient of variation (CV) of less than 10%, less than 8%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% of the dosing when performing repeated batch dosing of less than, for example, 200, 150, 100, 90, 80, 70, 60, 50, 40, 30, 20, or 10 pounds of carbon dioxide per batch, wherein the carbon dioxide is delivered as a liquid in a first conduit of the system and exits through an orifice into a second conduit of the system, wherein the carbon dioxide flows to the destination as a mixture of solid and gaseous carbon dioxide. In particular, the methods and assemblies of the present invention are useful when the dosage of carbon dioxide is low and the delivery time is short, but a mixture of solid and gaseous carbon dioxide is desired to be delivered at a high solid / gas ratio, even in the presence of significant pauses between runs and even at relatively high ambient temperatures. For example, the methods and assemblies of the present invention can be used to deliver carbon dioxide in intermittent fashion in a dosage of at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, or 120 pounds and / or not more than 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, or 120, such as 5 to 120 pounds, or 5 to 90 pounds, or 5 to 60 pounds, or 5 to 40 pounds, or 10 to 120 pounds, or 10 to 90 pounds, or 10 to 60 pounds, or 10 to 40 pounds, wherein the average time between doses is at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 40, 50, 60, 80, 100, or 120 minutes, wherein the delivery time of the doses is less than 180, 150, 120, 100, 90, 80, 70, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, or 10 seconds. The ratio of solid / gas carbon dioxide delivered to the target can be at least 0.3, 0.32, 0.34, 0.36, 0.38, 0.40, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, or 0.49. The reproducibility of the dosage between runs can be such that the coefficient of variation (CV) is less than 20%, 15%, 12%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1%.These values can be maintained even at relatively high ambient temperatures, such as average temperatures above 10°C, 15°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, or 40°C.

[0018] For example, using the methods and combination structures of the present application, it is possible to deliver intermittent doses of carbon dioxide from 5 to 60 pounds at an average solids / gas ratio of at least 0.4, where the delivery time is less than 60 seconds and the run interval time is at least 2, 4, 5, 7, or 10 minutes, where the ambient temperature is at least 25°C, where the CV is less than 10%, or even where the CV is less than 5%, 4%, 3%, 2%, or 1%. This short delivery time, high solids / gas ratio, and high reproducibility achieved during intermittent low doses is not possible with current equipment without substantial waste of carbon dioxide, for example, by continuously venting gaseous carbon dioxide from the line between runs. The methods and systems provided herein can allow for accurate, precise, and reproducible dosing of low doses of carbon dioxide, for example, as described above, where liquid carbon dioxide is converted to a mixture of solids and gaseous carbon dioxide without venting gaseous carbon dioxide in the line carrying the liquid carbon dioxide.

[0019] In current conventional installations where carbon dioxide is converted to solid and gas, a source of liquid carbon dioxide is connected via a conduit to an orifice, where the orifice opens to the atmosphere. Generally, the conduit extends a relatively short distance, such as 1 to 4 feet, beyond the orifice to direct the combination of solid and gaseous carbon dioxide to a desired destination. In typical current operations, the conduit from the source of liquid carbon dioxide to the orifice is well insulated; however, in intermittent operations, the conduit will warm to some extent depending on ambient temperature and the interval of use. If the interval of use is sufficiently long, the conduit can warm sufficiently so that when a new round of liquid carbon dioxide is released into the conduit, the carbon dioxide in the conduit has converted to gas between runs, and some of the carbon dioxide released into the conduit will convert to gaseous carbon dioxide, and typically, the first carbon dioxide out of the orifice is gaseous carbon dioxide. This can continue until the liquid carbon dioxide cools the conduit to a sufficiently low temperature so that the carbon dioxide remains in liquid form from its source to the orifice, and at this time, the desired mixture of solid and gaseous carbon dioxide is delivered. However, the first portion of carbon dioxide will be all or almost all gaseous carbon dioxide, and will be relatively large because of the length of the conduit extending from the source of carbon dioxide to the point of use. For use in, for example, food manufacturing processes and other such processes, this initial round of gaseous carbon dioxide is not problematic because precise dosing of the solid / gas mixture is not required, and because the application is done at intervals that allow little time for the conduit to equilibrate with the outside temperature.

[0020] However, there are applications that require precise dosing of carbon dioxide delivered at low dosages and in an intermittent manner at the desired ratio of solid to gaseous carbon dioxide. This requires that the carbon dioxide from the source to the orifice remain in liquid form, with the formation of a sufficiently small amount of gas so that the gas does not significantly affect the batching. It is possible to achieve this with cumbersome equipment, such as a liquid-gas separator in the line, or a counterflow mechanism in the snow cone itself for keeping the carbon dioxide in liquid form before it reaches the orifice (see, for example, U.S. Patent No. 3,667,242). However, such methods require venting of gas or re-liquefaction, both of which are wasteful, inefficient, and expensive to implement. This is especially wasteful in cases where the distance from the carbon dioxide source to the orifice, which is typically placed near the desired target for the snow cone to produce snow, is long, as this provides sufficient opportunity for the liquid carbon dioxide to convert to gas. There are many applications where the configuration of the various equipment on site does not allow for a short distance between a source of liquid carbon dioxide, such as a tank of liquid carbon dioxide, and the final destination of the carbon dioxide. For example, in concrete operations such as ready-mix concrete operations or precast operations, if it is desired to deliver a dose of carbon dioxide to the concrete mix in a mixer, the tank of liquid carbon dioxide will necessarily be located some distance from the point of delivery, such as typically 50 feet or more from the point of delivery.

[0021] Provided herein are methods and combinations that 1) allow for the transfer of liquid carbon dioxide from a source, such as a tank, to an orifice, where the liquid carbon dioxide is converted to solid and gaseous carbon dioxide, while maximizing the percentage of carbon dioxide that reaches the orifice as a liquid, without venting carbon dioxide or using insulated lines; 2) maximize the amount that remains solid as the carbon dioxide travels from the orifice to its point of use; and 3) allow for repeatable, reproducible batching under various environmental conditions and at low dosages of carbon dioxide.

[0022] In the methods and combination structures provided herein, a first conduit (also referred to herein as a transfer conduit or transfer line) carries liquid carbon dioxide from a reservoir to an orifice open to atmospheric pressure or a pressure close to atmospheric, the orifice being configured to convert the liquid carbon dioxide to solid and gaseous carbon dioxide. The first conduit is configured to minimize the amount of gaseous carbon dioxide produced initially in operation, and during the course of operation. Thus, the length of the first conduit from the source of liquid carbon dioxide to the orifice where the mixture of solid and gaseous carbon dioxide is produced is kept short, preferably as short as possible and / or kept to a set calibration length, and the diameter is kept to a value that allows the first conduit to achieve a small total volume without being so narrow as to induce a pressure drop of a value sufficient to cause conversion of the liquid to gaseous carbon dioxide within the conduit. The first conduit is typically not insulated and is made of a material such as woven stainless steel that can withstand the temperature and pressure of the liquid carbon dioxide. Because the length is short, the total heat capacity of the first conduit is low and the conduit rapidly equilibrates with the temperature of the liquid carbon dioxide as it initially enters the conduit. It will be appreciated that at very low ambient temperatures, i.e., ambient temperatures below the temperature of the carbon dioxide in the reservoir (which can vary depending on the pressure in the reservoir), the conduit will be at a temperature low enough that there will be little to no conversion of the liquid carbon dioxide to gas at the start of operation, but at ambient temperatures above the temperature at which the carbon dioxide will remain liquid in the conduit, some gas formation will inevitably occur; how much gas is formed depends on the temperature to which the conduit has reached between operations and the heat capacity of the conduit. However, even if the ambient temperature is relatively high (e.g., above 30°C) and the interval between operations is sufficient for the conduit to equilibrate with the ambient temperature, it only takes a very short time, e.g., less than 10, 8, 7, 6, 5, 4, 3, 2, or 1 second, to cool the conduit to the temperature of the liquid carbon dioxide flowing through it. As the liquid carbon dioxide flows through the conduit, further heat is lost to the outside air through the walls of the conduit during the flow time (assuming the ambient temperature is higher than the temperature of the liquid carbon dioxide), but because the diameter and length of the conduit are kept small, the flow is rapid and relatively little heat is lost by the time the carbon dioxide reaches the orifice. Thus, within a few seconds, e.g., within 10 seconds, or within 8 seconds, or within 5 seconds, a substantial portion, such as at least 80%, 90%, 92%, 95%, 96%, 97%, 98%, or 99% of the carbon dioxide will remain liquid by the time it reaches the orifice. Because the ratio of solid to gaseous carbon dioxide that exits the orifice is at least partially related to the proportion of the carbon dioxide that is liquid by the time it reaches the orifice, a ratio of solid to gas (by weight) close to 1 : 1 can be achieved within a few seconds.

[0023] The first conduit can have any suitable length, but must be short enough that a substantial amount of gas does not accumulate in the conduit (and needs to be removed before liquid carbon dioxide can reach the orifice). Thus, the first conduit can have a length of less than 30, 25, 20, 17, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, or 0.25 feet, and / or no more than 25, 20, 17, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.25, 0.1, or 0.01 feet, such as 0.1 to 25 feet, or 0.1 to 15 feet, or 0.1 to 10 feet, or 1 to 15 feet. Different systems, e.g., systems provided to different customers, can all include first conduits of the same length, diameter, and / or material, e.g., 10 feet long, or any other suitable length, so that calibration curves generated using the same length and type of conduit can be applied to different systems.

[0024] The inner diameter (I.D.) of the first conduit can be any suitable diameter; generally, a smaller diameter is preferred to reduce mass and travel time to the orifice, but the diameter cannot be so small that it causes a sufficient pressure drop over the length of the conduit to convert the liquid carbon dioxide to gas. The I.D. of the first conduit can thus be at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 inch, and no more than 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, or 2 inches, such as 0.1 to 0.8, or 0.1 to 0.6, or 0.2 to 0.7, or 0.2 to 0.6, or 0.2 to 0.5 inches, for example about 0.25 inches, or 0.30 inches, or 0.375 inches, or 0.5 inches. The first conduit that delivers the carbon dioxide to the orifice need not be highly insulated, and in fact can be made of a material with a high thermal conductivity, for example a metal conduit with a thin wall. For example, a woven stainless steel tube such as would be found inside a vacuum jacketed line (but without the vacuum jacket) can be used. The conduit can be rigid or flexible. Because the conduit is short and small diameter, it has a low thermal capacity, and thus, when liquid carbon dioxide is released into the conduit, the conduit is cooled very rapidly to the temperature of the liquid carbon dioxide, and the liquid carbon dioxide also travels rapidly through the length of the conduit, such that the time from the start of carbon dioxide delivery to the carbon dioxide delivered to the orifice is essentially all liquid carbon dioxide, or at least 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% liquid carbon dioxide, with only a short lag time. The lag time can be less than 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 second. The lag time will depend on the ambient temperature and the run interval; at low ambient temperatures and / or short run intervals, very little or no time will be needed for the first conduit to reach the temperature of the liquid carbon dioxide. At sufficiently low ambient temperatures, i.e., at or below the temperature that the liquid carbon dioxide achieves at the pressure being used, little or no time will be needed for the first conduit to reach equilibrium, as it is already at a temperature that will not produce any gaseous carbon dioxide as the liquid carbon dioxide passes through. An exemplary conduit is a 3 / 8 inch X 120 inch OA 321 SS braided hose, including St. steel MnPt fittings attached at each end.

[0025] Typically, the first conduit will contain a valve for starting and stopping the flow of carbon dioxide to the orifice, where the valve is located near the orifice. The section of the conduit between the valve and the orifice and / or the conduit after the orifice can experience freezing between runs. In certain embodiments, a separate gas conduit extends from the carbon dioxide source to the section of the first conduit between the valve and the orifice, and carries carbon dioxide gas through this section and the orifice to remove residual liquid carbon dioxide between runs.

[0026] In alternative embodiments, a gas conduit is not required. In these embodiments, the heat source is positioned such that the section of the conduit between the valve and the orifice, the orifice itself, and / or the section of the conduit after the orifice can be heated sufficiently between runs such that any liquid or solid in these sections and / or the orifice is converted to gas (this is typically only required if the solenoid is closed and the pressure drops, causing the carbon dioxide to drop to the gas / solid portion of the phase diagram, thereby causing some gas and solid snow that needs to be converted to gas by the introduction of heat before the next cycle). Further, the heat source can be comprised of a sufficient suitable material such that a heat sink can be created with sufficient capacity to sublimate any dry ice that forms between the valve and the orifice between cycles. When liquid carbon dioxide flows through the valve, the valve temperature approaches the equilibrium temperature of the liquid; closing the valve effectively causes the liquid to be trapped between the solenoid and the orifice, converting to gas and dry ice in approximately a 1 : 1 ratio, with the dry ice at, for example, -78.5°C. This causes more cooling of the valve, but in order to work, there must be sufficient mass in the heat sink to accept this cooling and still have capacity to sublimate the dry ice, which has a sublimation enthalpy of 571 kJ / kg (25.2 kJ / mole) before reaching -78.5°C. An exemplary heat sink can be constructed in a finned design, and comprised of any suitable material, such as aluminum. The fins assist the heat sink in quickly obtaining heat from the surrounding environment, and aluminum can be used due to its rapid heat conducting properties, allowing heat to quickly move to the valve and sublimate the dry ice. In certain embodiments, inductive heating can be used. This design allows for cycling at short intervals, such as a minimum interval of 10, 8, 7, 6, 5, 4, 3, 2, or 1 minute, such as a minimum interval time of about 5 minutes. Heating tape can be used in colder areas, and give a certain redundancy, such as a tape subject heater, for example a first tape subject heater wrapped around the heat sink below the liquid valve, and a second tape subject heater wrapped around the orifice. In certain embodiments, one or more inductive heaters can be used. In certain embodiments, one or more (e.g., 2) redundant pressure sensors can be included, such as so that if one pressure sensor fails, the other pressure sensor can start reading.

[0027] In these embodiments, the need for a gas line is avoided, reducing materials in the system. Further, since no gaseous carbon dioxide source is needed in addition to the liquid carbon dioxide source, the system can operate with smaller tanks that are not configured to pull gaseous carbon dioxide, such as mizer tanks or even portable dewars, which are not designed to output very high gas flow rates, e.g., soda fountain style tanks. These tanks are readily available to be installed immediately in such facilities, eliminating the need for custom committee tanks that are small enough to operate to assemble, but are assembled with gas lines.

[0028] In Figure 1 An example of a system that does not require a separate gas line is shown in FIG. 1. The CO2 piping assembly 100 includes a fitting 102 (e.g., ½” MNPT to ¼” FNPT), a valve 104 (e.g., ½” FNPT stainless steel solenoid valve rated for cryogenic liquids), a fitting 106 (e.g., ½” MNPT x ½” 2 FNPT tee), a nozzle 108 (e.g., stainless steel orifice), a heater 110, a fitting 112 (e.g., ½” MNPT thermocouple), a probe 114 (e.g., ½” MNPT temperature probe), a transmitter 116 (e.g., ¼” MNPT pressure sensor and transmitter), a fitting 118 (e.g., ½” MNPT x 4” nipple), a fitting 120 (e.g., ½” FNPT x ¾” FNPT), a transmitter 122 (e.g., temperature transmitter that can allow the probe to read temperatures below 0°C), and a heat sink 124.

[0029] The apparatus can include various sensors, which can include pressure sensors and / or temperature sensors. For example, there can be a first pressure sensor before the valve indicating the tank pressure, a second pressure sensor after the valve but before the orifice, and / or a third pressure sensor immediately after the orifice. For example, one or more temperature sensors can be used after the valve but before the orifice and / or after the orifice. Feedback from one or more of these sensors can be used, for example, to determine the flow rate of carbon dioxide. The flow rate can be determined by calculating using one or more of the pressure or temperature values. See, e.g., U.S. Patent No. 9,758,437.

[0030] Additionally or alternatively, the flow rate can be determined by comparison to a calibration curve, where such a curve can be obtained by measuring the flow, for example, measuring the change in weight of a liquid carbon dioxide reservoir using conduits and orifices similar or identical to those used in operation at various ambient temperatures and reservoir pressures, or any other suitable method. In either case, measurements of appropriate pressure and / or temperature in the system can be taken at intervals, such as at least every 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 3, 4, or 5 seconds and / or no more than every 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 3, 4, 5, or 6 seconds. The control system can also calculate the amount of carbon dioxide delivered based on the flow rate and time. In certain embodiments, such as for concrete operations, the control system can be configured to send a signal to a central controller of the concrete operation whenever a certain amount of carbon dioxide has flowed through the system; the central controller can be configured to, for example, count the signals and stop the flow of carbon dioxide after a predetermined number of signals corresponding to a required dose of carbon dioxide has been received. This is similar to the way such a controller regulates the amount of admixture added to a concrete mix. In some systems, the admixture is weighed by volume, in which case the system simulates the batching until a given weight by mimicking the weigh sensor output, and then when a signal is sent to drop the carbon dioxide into the mixer, the system uses the actual carbon dioxide discharged to count back from the target dose. This involves receiving a signal, and providing a feedback voltage based on the weight of the simulated (ghost) scale.

[0031] Alternatively, the temperature and pressure of the system can be matched to one or more appropriate calibration curves, or a series of curves generated by interpolation of the injection equation, and for a given dose, the time to deliver the dose is based on one or more appropriate injection equations. The control system can shut off the carbon dioxide flow after the appropriate time has elapsed. The calibration curve used at any given time can vary according to the temperature and / or pressure reading at that time.

[0032] In certain embodiments, a temperature sensor is used that gives instantaneous or near instantaneous feedback of the temperature of the liquid carbon dioxide and allows for increased accuracy in metering. The temperature sensor can also quickly detect when only gas is flowing through the system or if the tank is near empty. Without being limited by theory, it is believed that after the orifice, at temperatures less than -70°C, snow formation occurs and the solid formation region begins to affect the temperature of the liquid before the orifice, increasing the flow rate. This temperature sensor flow model can also indicate when the tank is deviating from equilibrium (e.g., after the tank is filled, when the ambient temperature is less than the liquid temperature, when a pressure builder on the tank is turned off, etc.). This model can allow for very low CV, for example less than 5%, or less than 3%, or less than 2%, or less than 1%. This model allows for elimination of the assumption of equilibrium between the carbon dioxide tank and the pressure and temperature of the liquid carbon dioxide. This model reads the pressure of the tank at the start of the shot and calculates the expected temperature of the liquid carbon dioxide based on the boiling curve equation derived from the carbon dioxide phase diagram. The system also takes an initial temperature reading and calculates the transition time, which is the time from when the liquid valve opens for liquid flow to start. During the transition time, a mixture of gas and liquid carbon dioxide is expected and a gas / liquid flow equation is used; after this, a liquid flow equation is used to calculate the flow of carbon dioxide. The model uses a linear equation derived from multiple shots across a range of tank pressures (e.g., more than 10, 100, 500, or more than 1000 shots) and is dependent on the upstream pressure. The model also has a pressure multiplier, where the pressure multiplier calculates the pressure drop from the inlet liquid pressure sensor to the upstream pressure sensor and changes the flow if the difference between these two sensors deviates. The multiplier adjusts the flow accordingly if there is any obstruction in the tubing of the system. A temperature multiplier takes readings from the temperature sensor and compares the temperature read to the calculated temperature of the liquid carbon dioxide. The temperature multiplier changes the flow accordingly if the sensor reads a temperature that is lower or higher than the calculated value. Existing systems can have new pressure sensors; a higher valve housing for quick and easy repair; and new inspection and hydraulic mounting brackets on the downstream pressure sensor for increased durability to eliminate the sensor in the cold region where snow formation exists after the orifice. Hydraulic brackets have been proven to significantly reduce the failure rate of the downstream pressure sensor.

[0033] The carbon dioxide is converted at the orifice into a mixture of gaseous and solid carbon dioxide; the ratio of solid to gas produced at the orifice depends on the proportion of carbon dioxide arriving at the orifice as a liquid. If the carbon dioxide arriving at the orifice is 100% liquid, the proportion of solid to gaseous carbon dioxide in the mixture of solid and gaseous carbon dioxide exiting the orifice can approach 50%. The orifice can be any suitable diameter, such as at least 1 / 64, 2 / 64, 3 / 64, 4 / 64, 5 / 64, 6 / 64, or 7 / 64 inch and / or no more than 2 / 64, 3 / 64, 4 / 64, 5 / 64, 6 / 64, 7 / 64, 8 / 64, 9 / 64, 10 / 64, 11 / 64, or 12 / 64 inch, such as about 5 / 64 inch, or about 7 / 64 inch. The length of the orifice must be sufficient that the liquid carbon dioxide passing therethrough does not freeze; further, the orifice can be flared to prevent clogging. In certain systems, a dual orifice manifold block is used, which allows one valve to feed two orifices and two discharge lines.

[0034] In a dual orifice system, a given flow of carbon dioxide can be delivered to a destination in a shorter time, and / or the flow can be delivered to two different destinations, and / or the flow can be delivered to a single destination at two different points in the destination (e.g., two different points in a mixer, such as a concrete mixer), which can allow more efficient uptake of the carbon dioxide at the destination. This can avoid reliability and accuracy issues in certain systems, e.g., dual axle or dual roller mixers for concrete, or other systems with very short cycle times. Thus, a dual orifice system can allow up to twice the delivery (e.g., up to 1.8 times a single orifice system; the delivery does not reach theoretical 2 times due to thermodynamic changes within the system) in a given time, as well as more targeted delivery (to, e.g., two different points in a mixer), allowing, e.g., greater uptake efficiency. A dual orifice system can be made and used in any suitable manner. For example, a steel manifold, such as a steel or stainless steel manifold, can be fully machined and contain one inlet and two outlets with suitable orifices, e.g., orifices of the sizes described herein, such as 7 / 64" orifices. The manifold can have connections for two downstream pressure sensors and a tee for a temperature sensor and an upstream pressure sensor to reduce the mass of the system and the time of liquid and metal contact. A dual injection system calculates the flow rate through both orifices. A dual injection system can also have an additional slipstream discharge hose (a second conduit as described herein), an additional injection nozzle, an additional downstream pressure sensor with a bracket, and / or two discharge points in a mixer.

[0035] The mixture of gaseous and solid carbon dioxide is then directed from the orifice through a second conduit to its point of use, for example to a location to deliver the mixture to a mixer containing a cement mix comprising hydraulic cement and water, such as a drum of a ready-mix truck or a central mixer, in the case of a concrete operation such as a ready-mix operation or a precast operation, the second conduit also being referred to herein as a delivery conduit or delivery line. The second conduit is configured to deliver the mixture of solid and gaseous carbon dioxide to its point of use with very little conversion of solid to gaseous carbon dioxide, such that the mixture of solid and gaseous carbon dioxide at the point of use is still at a high ratio of solid to gas, for example, the proportion of solid carbon dioxide in the mixture can be at least 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48% or 49% of the total.

[0036] The second conduit is generally configured to minimize friction along its length, and also to minimize heat exchange with the ambient atmosphere, and additionally to provide a small overall volume so that the flow rate is maximized. For example, the second conduit can be a slip-fit conduit having a relatively small diameter. Any suitable means can be used to provide a slip fit for the second conduit, such as ensuring that there are no irregularities on the inner surface of the conduit and that there is no crimping of the conduit. A material having a coating such as polytetrafluoroethylene (PTFE) can be used, which serves to keep the conduit lumen smooth, so long as there are not a large number of irregularities or crimping. The thermal mass of the hose is low due to the thin PTFE and small amount of stainless steel braid. The hose can be insulated, for example, with conventional pipe insulation. The conduit should generally be smooth (not crimped) to allow for smooth flow, and the conduit must be able to withstand low temperatures; that is, the dry ice (snow) passing through the hose will be at a temperature of -78°C. An exemplary second conduit is a conduit of the SmoothFlex series produced by PureFlex, Kentwood, MI. The materials and weights used in the SmoothFlex series make these conduits good candidates for ensuring minimal warming during transport of the carbon dioxide from the orifice to its destination. This maximizes the solid carbon dioxide fraction while the sublimation rate remains low. The second conduit can be flexible or rigid or a combination thereof; in certain embodiments, at least a portion can be flexible to facilitate positioning or changing location. The second conduit can direct the mixture of solid and gaseous carbon dioxide over long distances with little conversion of solid to gas, because the transport time through the conduit is relatively short, due to the force generated in the sudden conversion of liquid carbon dioxide to gas and the subsequent 500-fold or more expansion that will force the mixture of gas and solid through the conduit. The inner diameter of the second conduit can be any suitable inner diameter that allows for rapid passage of carbon dioxide, for example at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0 inch, and / or no more than 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, or 2 inches, such as 0.5 inches, or 0.625 inches, or 0.750 inches. The length of the second conduit can be, for example, at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 80, 90, or 100 feet, in order to reach the final point at which the carbon dioxide will be used; the length of the second conduit will generally depend on the particular operation set-up in which the carbon dioxide is being used.Because the first conduit is generally kept as short as possible, and the second conduit must be of a length suitable to reach the point of use, often far from the injector orifice, the ratio of the length of the second conduit to the first conduit can be at least 0.5, 0.7, 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6, 7, 8, 9, or 10, or greater than 10. For example, the length of the first conduit can be no more than 10 feet, while the length of the second conduit can be at least 20, 30, 40, or 50 feet. The second conduit can be placed inside another conduit, such as a loosely fitted plastic hose, for example, to prevent kinking during installation. The second conduit can be further insulated, for example, with pipe insulation, to further minimize heat gain from external sources between injections.

[0037] In certain embodiments, an admixture can be added to the carbon dioxide stream as it is being delivered. The admixture can be, for example, a liquid. A small amount of liquid admixture can be mixed into the discharge line after the orifice. The liquid can freeze rapidly into a solid form and be carried along with the carbon dioxide into the mixer. The frozen admixture is carried along with the carbon dioxide into the concrete mix and melts or sublimates in the concrete mix. This method is particularly useful when the admixture has a synergistic effect with the carbon dioxide, and / or is capable of affecting the carbonation reaction of the carbon dioxide. For example, the admixture TIPA provides benefits at very small dosages, but it is typically added as a liquid mixture, so a small dosage is accompanied by a large amount of carrier liquid. If only the active ingredient is added, a small amount of active ingredient can be distributed over the dosage of carbon dioxide. If the chemical does not need to be added as a dilute solution, the admixture system can be smaller.

[0038] The second (delivery) conduit can be attached to a third conduit, which is also referred to herein as a target-aiming conduit. The third conduit can be of a larger diameter than the second conduit to allow the solid / gaseous carbon dioxide to slow down and mix so that the solid carbon dioxide clumps together into larger pellets. This is useful, for example, in concrete operations where the carbon dioxide is added to a mixing cement mixture so that the pellets are large enough to be incorporated into the mixing cement before significant sublimation. The third conduit can be of any suitable internal diameter, so long as the internal diameter allows sufficient slowing and clumping to achieve the desired use, for example, at least at least 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.2, 3.4, 3.8, or 4 inches, and / or no more than 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.2, 3.4, 3.8, or 4 inches.

[0039]

[0040] 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.2, 3.4, 3.8, 4, or 4.5 inches, such as 0.5 to 4 inches, or 0.5 to 3 inches, or 0.5 to 2.5 inches, or about 2 inches. The third conduit can be any suitable length to allow for the desired agglomeration without excessive deceleration of the carbon dioxide, or too long so that material sticks to the wall or sublimates significantly, for example at least 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 32, 36, 40, 44, or 48 inches, and / or no more than 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 32, 36, 40, 44, 48, 54, 60, 72, 84 inches, for example 2 to 8 feet, or 2 to 6 feet, or 3 to 6 feet, or 3 to 5 feet. The third conduit is typically made of a material that is rigid, and sufficiently durable to withstand the conditions in which it is used. For example, in a concrete mixing operation, the third conduit is typically positioned in a chute through which material including aggregate is funneled into a mixer, and is in repeated contact with moving aggregate, and should have sufficient strength and durability to withstand repeated contact with aggregate on a daily basis. There can be up to 20 tons of material per truck, and 400 to 500 trucks per month. Conventional snow cone material cannot withstand this environment. A suitable material is stainless steel with a suitable diameter, such as 1 / 8 to 1 / 4 inch. In some cases, it can be desirable to install armor, for example at high wear locations, to increase the thickness to, for example, 1 / 2 inch or even thicker. The third conduit is typically a high wear item, and can be serviced regularly, for example every 3 to 6 months depending on production. In certain operations, for example where the third conduit is not moved, or is moved only slightly or rarely between runs, the third conduit can be the final conduit in the system. This is the case, for example, in a stationary mixer, such as a central mixer used in, for example, a ready mix operation.

[0041] In some operations, such as a concrete mixing operation in which mixed material is dropped into a drum of a ready mix truck, the material is dropped through a chute that terminates in a flexible section, to allow the chute to be placed in the hopper of the drum, and then removed. In this case, a fourth conduit of flexible material, also referred to herein as an end conduit, can be attached to the third conduit so as to move with the flexible chute used to drop the concrete material. The inner diameter of the flexible conduit is such that it fits closely over the outer diameter of the third conduit. Any material with suitable flexibility and durability can be used in the fourth conduit, such as silicone.

[0042] In certain embodiments, a token system is used as a security measure. For example, every so often (e.g., every month), a unique key (or "token") is generated and distributed to the customer if the customer has no unpaid fees; if there are unpaid fees or other violations, the token can be withheld. The customer enters the token into the system, e.g., via a touchscreen or on a web interface display (serves the same function as a touchscreen, but is displayed on the batching computer, i.e., is suitable for potential installation of the system without a touchscreen). At the end of the time interval (e.g., one month), the system program disables the system unless the unique key has been entered; e.g., without the unique key, the system will enter idle mode, and even if a start-spraying signal is sent to the system, it will be ignored. This can also occur if, e.g., the system loses network connection for a period of time (e.g., if the customer disables the network signal in order to run the system without a unique key). Additionally or alternatively, an external connector can be used for input and output on the housing, which allows the provider to manually or automatically disable the system if any attempt to tamper with the housing has occurred. Neither the customer nor the installer has a reason to open the housing; in the event of a failed component, the customer can be asked to remove the external connection and a replacement component can be sent to replace the failed component.

[0043] Example 1

[0044] Pre-mix concrete plants provide dry ingredients in their trucks; that is, the dry concrete ingredients are placed in the truck's drum with water and the concrete is mixed in the truck. It is desirable to deliver carbon dioxide to the truck while the concrete is mixing, where the carbon dioxide is in a high ratio of solid carbon dioxide, such as at least 40% solid carbon dioxide, a mixture of solid and gaseous carbon dioxide. There is no room in the batching facility for a liquid carbon dioxide storage tank to feed the truck's line, so the liquid carbon dioxide storage tank is located 50 feet or more from the final destination. Over the course of a day, it is desirable to deliver a dose of 1% carbon dioxide by weight of cement (bwc) to successive concrete batches in different trucks. The trucks can be full of 10 cubic yards of concrete, or partially loaded with as little as 1 cubic yard of concrete. A typical concrete batch uses 15% cement by weight, and a certain typical cubic yard of concrete has a weight of 4000 pounds, so 1 cubic yard of concrete will contain 600 pounds of cement. Thus, the minimum dose of carbon dioxide will be 6 pounds, and the maximum dose will be 60 pounds. The average time between doses is at least 10 minutes.

[0045] Liquid carbon dioxide is directed from a storage tank to an orifice configured to convert the liquid carbon dioxide into solid and gaseous carbon dioxide as it is released to atmospheric pressure via a 10 foot 3 / 8 inch ID braided stainless steel line. As the mixture of solid and gaseous carbon dioxide is released through the orifice, it is directed toward the drum of a ready mix truck via a 50 foot 5 / 8 inch ID slip cavity and insulated line. This line terminates in a 2 inch ID ¼ inch thick and 2 foot long stainless steel tube that is contained inside a chute that directs the concrete ingredients from their respective storage containers to the drum of the truck; the stainless steel line in turn terminates in a flexible section that is fitted on the stainless steel tube that moves with the rubber boot at the end of the chute that hangs into the hopper of the ready mix truck.

[0046] The system is calibrated against a calibration system that tests flow rates at various temperature and pressure conditions using an initial conduit of the same length, diameter, and material. The appropriate pressure and temperature are acquired for a given batch during operation of the system and are matched to the appropriate calibration curve or curves to determine the flow rate and length of time required to deliver the desired dose, and the carbon dioxide flow is stopped when the system has determined that 1% of the bwc has been delivered to the truck.

[0047] The ambient temperature range throughout the day is between 10°C and 25°C. Each truck remains in the loading area while the material is loaded in a time of up to 90 seconds, and the delivery time of carbon dioxide is less than 45 seconds.

[0048] The system delivers the appropriate dose to achieve 1% carbon dioxide bwc in a time of 8 hours with a ratio of solid / total carbon dioxide of at least 0.4, with an average of 5 loads per hour (40 loads in total), with a precision of less than 10% coefficient of variation.

[0049] While the preferred embodiments of the application have been shown and described herein, it will be apparent to those skilled in the art that many changes, modifications, and substitutions can be made thereto without departing from the application. It is to be understood that various alternatives to the embodiments of the application described herein can be employed in practicing the present application. It is intended that the following claims define the scope of the application and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

1. An apparatus for delivering solid and gaseous carbon dioxide, the apparatus comprising: (i) a source of liquid carbon dioxide, the source of liquid carbon dioxide comprising a reservoir filled with liquid carbon dioxide; (ii) a first conduit, wherein the first conduit comprises a proximal end operably connected to the source of liquid carbon dioxide, and a distal end operably connected to an orifice, wherein (a) the first conduit comprises a material capable of withstanding the temperature and pressure of the liquid carbon dioxide, (b) the first conduit is configured such that when the ambient temperature is less than 30°C, the liquid carbon dioxide entering the first conduit reaches the orifice as at least 90% liquid carbon dioxide, and (c) the orifice opens to atmospheric pressure, or near atmospheric pressure, and is configured to convert the liquid carbon dioxide to a mixture of solid and gaseous carbon dioxide as it passes through the orifice; (iii) a second conduit operably connected to the orifice to direct the mixture of gaseous and solid carbon dioxide to a desired destination, wherein (a) the second conduit is at least 10 feet in length, (b) the ratio of the length of the second conduit to the length of the first conduit is at least 2: 1, and (c) the second conduit comprises a slipstream; and (iv) a third conduit operably connected to the second conduit, wherein the third conduit comprises a portion configured to substantially slow the flow of the solid carbon dioxide through the portion of the third conduit, such that the solid carbon dioxide agglomerates before it exits the third conduit through an opening.

2. The apparatus of claim 1, wherein the first conduit is not insulated.

3. The apparatus of claim 1, wherein the ratio of the length of the third conduit to the length of the second conduit is less than 0.1:

1.

4. The apparatus of claim 1, wherein the third conduit has a length of between 1 and 10 feet.

5. The apparatus of claim 1, wherein the third conduit has an inner diameter of between 1 inch and 3 inches.

6. The apparatus of claim 1, wherein the first conduit has a length of less than 15 feet.

7. The apparatus of claim 1, wherein the first conduit has an inner diameter of between 0.25 and 0.75 inches.

8. The apparatus of claim 1, wherein the first conduit comprises an internal material of braided stainless steel.

9. The apparatus of claim 1, wherein the second conduit has a length of at least 30 feet.

10. The apparatus of claim 1, wherein the second conduit has an inner diameter of between 0.5 and 0.75 inches.

11. The apparatus of claim 1, wherein the second conduit comprises an internal material of polytetrafluoroethylene.

12. The apparatus of claim 1, wherein the third conduit comprises a rigid material, and is operably connected to a fourth conduit comprising a flexible material.

13. The apparatus of claim 12, wherein the combined length of the third conduit and the fourth conduit is between 2 and 10 feet.

14. The apparatus of claim 1, wherein the first conduit includes a valve to regulate the flow of carbon dioxide, a first sensor to determine pressure between the valve and the orifice, and a second sensor to determine temperature between the valve and the orifice.

15. The apparatus of claim 14, further comprising a control system, the first sensor and the second sensor communicating information about pressure and temperature to the control system, and the control system determining a flow rate of carbon dioxide based at least in part on the information.

16. The apparatus of claim 1, further comprising a mixer, a flow of carbon dioxide from the third conduit flowing into the mixer.

17. The apparatus of claim 16, wherein the mixer is a concrete mixer.

18. The apparatus of claim 17, wherein the concrete mixer is a stationary mixer.

19. The apparatus of claim 17, wherein the mixer is a transportable mixer.

20. The apparatus of claim 19, wherein the mixer is a drum of a ready-mix truck.

21. The apparatus of claim 12, wherein the first conduit, the second conduit, the third conduit, and the fourth conduit are directed to add carbon dioxide to a concrete mixer, and wherein cement is added to the mixer through a cement conduit, the cement conduit including a first portion comprising a rigid cement chute, the rigid cement chute first portion connected to a second portion comprising a flexible sheath, the second portion configured to allow a ready-mix truck to move a hopper on the ready-mix truck onto the sheath such that the sheath is suspended into the hopper, allowing cement and other ingredients to fall through the sheath into a drum of the ready-mix truck, wherein the third conduit is positioned alongside the first portion of the cement conduit, and the fourth conduit is positioned to self-move and direct with the second portion of the cement conduit.

22. The apparatus of claim 21, wherein aggregate is added to the mixer through an aggregate chute adjacent to the rigid cement chute, and wherein a first portion of the third conduit is positioned to reduce contact with the aggregate as the aggregate exits the aggregate chute.

23. The apparatus of claim 22, wherein the first portion of the third conduit extends to a bottom of the first portion of the rigid cement chute, and the fourth conduit is attached to an end of the third conduit and extends from the end of the third conduit to a bottom of a rubber sheath, or near the bottom of the rubber sheath, when the rubber sheath is positioned within the hopper of the ready-mix truck.

24. The apparatus of claim 23, wherein the fourth conduit is normally positioned within x cm of the center of the rubberized boot when the rubberized boot is positioned to load a concrete material into the drum of the ready-mix truck, wherein x = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, or 90 cm.

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