Method for treating process condensate
First Claim
1. A method for treating an ammonia production plant process effluent stream of dilute ammonia contaminants and an ammonia production plant low pressure purge gas stream of dilute ammonia contaminants, said method comprising the following steps:
- stripping at least a portion of ammonia contaminants from a process effluent obtained from an ammonia production plant, wherein said stripping is conducted in a stripping section to obtain an ammonia contaminant-rich vapor stream and an aqueous bottom stream of reduced ammonia contaminant content;
rectifying said ammonia contaminant-rich vapor stream in a rectification section to obtain a concentrated overhead stream;
condensing said concentrated overhead stream to obtain ammonia contaminant-rich overhead condensate and non-condensed gases comprising trace amounts of the ammonia contaminates;
scrubbing said non-condensed gases and a purge gas stream of dilute ammonia contaminates with water so as to recover a portion of said trace amounts of the ammonia contaminates from the non-condensed gases and said dilute ammonia contaminates from the purge gas stream into said ammonia contaminant-rich overhead condensate;
recycling said overhead condensate to said rectifying step to form a closed loop so as to build up the concentration of ammonia contaminants in said overhead condensate;
separating and withdrawing from said closed loop a fraction of said overhead condensate; and
reusing said fraction of the overhead condensate in the ammonia production plant.
3 Assignments
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Accused Products
Abstract
An apparatus and method for treating chemical production plant process condensate and low pressure purge gas such that a contaminant-rich stream is recoverable from the condensate and purge gas, wherein the contaminants are substantially removed from the condensate by steam stripping and subsequent rectification in a relatively low pressure stripping/rectification tower. The tower overhead is then condensed, and any non-condensed gases are subjected to water scrubbing, along with the low pressure purge gas to further recover contaminates from the non-condensed gas. A portion of the condensed overhead and scrubbing water containing contaminates is returned to the top of the rectification section of the tower as reflux and the balance being withdrawn as a concentrated stream for reuse in the plant. The apparatus may be used in conjunction with existing low pressure equipment, avoiding costly major modifications, and is particularly adapted to use in conjunction with ammonia and methanol plants.
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Citations
23 Claims
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1. A method for treating an ammonia production plant process effluent stream of dilute ammonia contaminants and an ammonia production plant low pressure purge gas stream of dilute ammonia contaminants, said method comprising the following steps:
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stripping at least a portion of ammonia contaminants from a process effluent obtained from an ammonia production plant, wherein said stripping is conducted in a stripping section to obtain an ammonia contaminant-rich vapor stream and an aqueous bottom stream of reduced ammonia contaminant content; rectifying said ammonia contaminant-rich vapor stream in a rectification section to obtain a concentrated overhead stream; condensing said concentrated overhead stream to obtain ammonia contaminant-rich overhead condensate and non-condensed gases comprising trace amounts of the ammonia contaminates; scrubbing said non-condensed gases and a purge gas stream of dilute ammonia contaminates with water so as to recover a portion of said trace amounts of the ammonia contaminates from the non-condensed gases and said dilute ammonia contaminates from the purge gas stream into said ammonia contaminant-rich overhead condensate; recycling said overhead condensate to said rectifying step to form a closed loop so as to build up the concentration of ammonia contaminants in said overhead condensate; separating and withdrawing from said closed loop a fraction of said overhead condensate; and reusing said fraction of the overhead condensate in the ammonia production plant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for treating a methanol production plant process effluent stream of dilute methanol contaminants and a methanol production plant low pressure purge gas stream of dilute methanol contaminants, said method comprising the following steps:
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stripping at least a portion of methanol contaminants from a process effluent obtained from a methanol production plant, wherein said stripping is conducted in a stripping section to obtain a methanol contaminant-rich vapor stream and an aqueous bottom stream of reduced methanol contaminant content; rectifying said methanol contaminant-rich vapor stream in a rectification section to obtain a concentrated overhead stream; condensing said concentrated overhead stream to obtain methanol contaminant-rich overhead condensate and non-condensed gases comprising trace amounts of the methanol contaminates; scrubbing said non-condensed gases and a purge gas stream of dilute methanol contaminates with water so as to recover a portion of said trace amounts of the methanol contaminates from the non-condensed gases and said dilute methanol contaminates from the purge gas stream into said methanol contaminant-rich overhead condensate and a scrubbed purge gas; recycling said overhead condensate to said rectifying step to form a closed loop so as to build up the concentration of methanol contaminants in said overhead condensate; separating and withdrawing from said closed loop a fraction of said overhead condensate; and reusing said fraction of the overhead condensate in the methanol production plant. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification