Drying and gas or vapor contact with solids – Process – Gas or vapor pressure is subatmospheric
Reexamination Certificate
2001-07-09
2003-03-18
Lazarus, Ira S. (Department: 3749)
Drying and gas or vapor contact with solids
Process
Gas or vapor pressure is subatmospheric
C034S437000, C034S092000, C034S104000
Reexamination Certificate
active
06532684
ABSTRACT:
1. Field of Invention
The present invention relates to a system for cleaning pressurized containers having chemicals contained therein. Specifically, the present invention relates to a system for cleaning pressurized containers such as, for example, rail tank cars, mobile tanks or the like. Further, the chemicals may comprise any material stored under pressure that may be difficult to collect and dispose of due to the hazardous characteristics thereof. Moreover, the chemicals may further be highly reactive to moisture and may form damaging acids or other reaction products when contacting water.
2. Background of the Invention
It is, of course, generally known to store and/or transport chemicals having hazardous characteristics via pressurized containers. Further, it is also generally known to clean these containers using a variety of methods and systems. In the past, cleaning pressurized containers entailed venting excess gaseous material to the atmosphere. Further, unpressurized containers contained bottom hatches or valves for draining liquid chemicals. However, many hazardous chemicals escaped into the environment thereby causing health risks for humans, vegetation and wildlife. With the advent of environmental standards and compliance, however, venting or draining hazardous chemicals to the environment has generally become illegal.
Moreover, some chemicals that may be stored within pressurized containers may be highly reactive in the presence of water and may form acids that may be damaging to equipment as well as the environment. Although a flare may be useful to dispose of chemicals that are flammable, some chemicals do not incinerate easily or may form extremely hazardous substances upon incineration. Typically, scrubbers or sparge tanks are necessary to dispose of these chemicals or byproducts of these chemicals.
While some of the gases contained within the containers may be relatively easy to recover and dispose of by venting the pressurized containers to a flare or to a sparge tank, it is difficult to remove all of the gases contained therein. Further, liquid product may remain inside a container after cleaning. Typical systems and methods of cleaning pressurized containers may involve injecting the container with a quantity of steam that may aid in bringing the liquid chemicals to the gaseous phase and removing the steam/gaseous chemical product combination for incineration or disposal. However, problems may occur using steam to remove chemicals from pressurized containers since steam may condense within the container forming liquid water or ice. The liquid water or ice may mask the presence of the chemicals from detectors or otherwise encapsulate the chemicals. Further, the liquid water or ice may interfere with the removal of the chemicals from the container. Moreover, liquid water or steam may react with certain chemicals, such as for example, chlorine gas or sulfur dioxide gas to form hazardous byproducts, such as acids, that may damage equipment or the environment if released. For example, chlorine gas and sulfur dioxide gas may react with water according to the following reaction:
Cl
2
+H
2
O→HCl+HOCl 1.
2 SO
2
+2 H
2
O+O
2
→2 H
2
SO
4
2.
In addition, steam or liquid water may be difficult to remove from the container since water droplets may stick to the inside surfaces of the container, piping and/or equipment. A further step would be required for drying the container and/or the equipment, thereby requiring additional time, equipment and expense.
Another method of removal may include entering the container to manually remove the chemical and/or any other debris, such as, for example, scaling, that may be contained within the container. While this may be a relatively thorough way to remove the chemical from the container, it may be very dangerous, as it requires an individual to actually enter the container thereby exposing the individual to any chemicals that may be contained therein. Further, by opening the container, there may be a significant risk that some of the chemicals may escape into the environment.
Therefore, an improved system of cleaning pressurized containers is necessary. Particularly, a system is needed that overcomes the problems associated with typical cleaning systems. Further, a system is needed that cleanly and efficiently removes chemicals from a pressurized container and transports the waste product to a proper disposal system such as a flare or a reaction tank to incinerate or otherwise safely dispose of the chemicals.
SUMMARY OF THE INVENTION
The present invention relates to a system for cleaning a pressurized container having chemicals therein. More specifically, the present invention allows mobile containers such as, for example, rail tank cars, to be cleaned safely and efficiently without risking exposure of the chemicals to people or the environment. The invention entails injecting heated and pressurized nitrogen gas or ambient air into the container thereby purging the container of any chemical therein and forming a nitrogen/chemical mixture. The nitrogen/chemical mixture may then be sent to a flare for incineration or a reaction tank for neutralization of the chemical. Further, the heated nitrogen gas may aid in pulling the chemical out of the container and transporting the chemical to the flare for incineration. In addition, a vacuum pump may be utilized to further aid in the removal of the nitrogen/chemical mixture from the container.
To this end in an embodiment of the present invention, a system for cleaning pressurized containers containing chemicals is provided. The system comprises: a container having a quantity of chemicals therein wherein the container has a plurality of valves for attaching a plurality of pipes thereto; a nitrogen gas storage tank wherein the nitrogen gas storage tank is attachable to a first valve on the container; a heat exchange means wherein the first pipe is heated by the heating means; a tank containing a caustic material connected to the container via a pipe; and a vacuum pump disposed between the container and the tank.
Further, a system is provided wherein the plurality of valves regulates a flow of nitrogen gas from the nitrogen gas storage tank and the container. Still further, the container is a railcar. Alternatively, the container is disposed on a vehicle.
Moreover, the present invention provides a system that further comprises a heating means connected to the heat exchange means for feeding a fluid to the heat exchange means for heating nitrogen gas that flows through the heat exchange means. Moreover, the system comprises a nitrogen vaporizer attached to a second section of the first pipe for vaporizing the nitrogen from the nitrogen storage tank.
In addition, a pipe within the container is attached to a valve wherein the first pipe within the container extends to a bottom of the container. Additionally, a pipe within the container is attached to a valve and extends partially within the container.
In a further embodiment of the present invention, the system comprises a controller interconnected with the plurality of valves for controlling the opening and closing of the valves. Moreover, the controller controls the vacuum pump. Moreover, the controller controls the opening and closing of the plurality of valves in synchronization with the vacuum pump.
In addition, the system further comprises a gauge attached to the container for measuring the internal pressure of the container. In addition, the tank comprises a quantity of a material selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium carbonate, calcium hydroxide, sodium sulfite, sodium thiosulfite, ferrous chloride and solid bed absorbents. Further, the tank neutralizes chlorine gas and sulfur dioxide gas. Still further, a first pipe extends from the container to the vacuum pump and a second pipe extends from the vacuum pump to the tank containing the caustic material.
In an alternate embodiment of the present invention, a system for cleaning pressuri
Buchan Paul
Davis Thomas J.
Tunney Joseph P.
Vermette Raymond Blaine
General Electric Company
Lazarus Ira S.
Rinehart K. B
LandOfFree
System for cleaning pressurized containers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System for cleaning pressurized containers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System for cleaning pressurized containers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3061244