Apparatus and method for improved hydrate formation and improved efficiency of recovery of expansion agent in processes for expanding tobacco and other agricultural products

A method for recovering additional expansion agent in a batch process for the expansion of tobacco or another agricultural product, the batch process having a means for depressurizing an impregnation vessel, comprising the steps of:

• withdrawing substantially all of an amount of expansion agent in the impregnation vessel during the depressurization of the impregnation vessel;
• transmitting, without collection, substantially all of said amount of expansion agent to at least one compressor;
• and
• compressing substantially all of said amount of expansion agent to a pressure sufficient to condense the expansion agent.

A method for recovering additional expansion agent in a process for the expansion of tobacco or another agricultural product, the process having a multi-step depressurization sequence including at least first and second depressurization steps for depressurizing an impregnation vessel, comprising the steps of:

• withdrawing substantially all of an amount of expansion agent in the impregnation vessel at about the end of the second depressurization step during the multi-step depressurization sequence;
• compressing at least a portion of said amount of expansion agent to a pressure sufficient to condense the expansion agent;
• and
• determining an optimum depressurization mass flowrate for maximum hydrate formation over a range of pressures of depressurization from an initial impregnation pressure to a pressure where the expansion agent ceases to form water hydrate.

A batch process for the expansion of tobacco or another agricultural product wherein the batch process includes a method for recovering additional expansion agent, the batch process having a means for depressurizing an impregnation vessel, comprising the steps of:

• withdrawing substantially all of an amount of expansion agent in the impregnation vessel during the depressurization of the impregnation vessel;
• transmitting, without collection, substantially all of said amount of expansion agent to at least one compressor;
• and
• compressing substantially all of said amount of expansion agent to a pressure sufficient to condense the expansion agent.

A method for recovering additional expansion agent in a process for the expansion of tobacco or another agricultural product, the process having a multi-step depressurization sequence including at least first and second depressurization steps for depressurizing an impregnation vessel, comprising the steps of:

• withdrawing substantially all of an amount of expansion agent in the impregnation vessel at about the end of the second depressurization step during the multi-step depressurization sequence;
• compressing at least a portion of said amount of expansion agent to a pressure sufficient to condense the expansion agent;
• and
• determining an optimum depressurization mass flowrate for maximum hydrate formation over a range of pressures of depressurization from an initial impregnation pressure to a pressure where the expansion agent ceases to form water hydrate by
• (a) setting the mass flowrate of the expansion agent at a selected mass flowrate;
• (b) determining an amount of expanding agent present in an impregnated product at about the end of an impregnation cycle;
• (c) adjusting by an incremental amount the mass flowrate of the expansion agent;
• and
• (d) repeating (b), (c) and (d) until a maximum amount of expanding agent is determined to be present in the impregnated product.