Method for monitoring organic deposits in papermaking

Abstract

A method for monitoring the deposition of organic deposits from a liquid or slurry in a papermaking process is disclosed. Also disclosed is a method for measuring the effectiveness of inhibitors that decrease the deposition of organic deposits in a papermaking process. The method may involve monitoring the deposition of organic deposits of a liquid or slurry that simulates the conditions of a papermaking process. The methods may comprise the steps of monitoring the rate of deposition of organic deposits; adding an inhibitor that decreases the deposition of organic deposits from the liquid or slurry; and optionally re-measuring the rate of deposition of organic deposits from the liquid or slurry onto the quartz crystal microbalance, with the rates of deposition determined by measuring the vibration frequency of the quartz crystal microbalance.

1 . A method for monitoring and controlling a rate of deposition of organic deposits from a liquid or slurry in a papermaking process, the method comprising:
 providing a quartz crystal microbalance, the quartz crystal microbalance having a top side in contact with the liquid or slurry and a bottom side isolated from the liquid or slurry, the quartz crystal microbalance measuring a vibration frequency;   monitoring the rate of deposition of the organic deposits from the liquid or slurry by measuring the vibration frequency; and   adding an inhibitor to the liquid or slurry, the inhibitor decreasing the rate of deposition of the organic deposits from the liquid or slurry, wherein the adding is based upon the monitoring.   
     
     
         2 . The method of  claim 1  wherein the top side of the quartz crystal microbalance comprises at least one conductive material selected from the group consisting of: platinum, titanium, silver; gold; lead; cadmium; diamond-like thin film electrodes with or without implanted ions; silicides of titanium, niobium and tantalum; lead-selenium alloys; mercury amalgams; and silicon. 
     
     
         3 . The method of  claim 1  wherein the method is performed at a location selected from the group consisting of: a pulp mill; a papermaking machine; a tissue making machine; a repulper; water loop; wet-end stock preparation; and a deinking stage. 
     
     
         4 . The method of  claim 1  wherein the organic deposits are selected from the group consisting of at least one of the following: wood extractives; related natural materials in virgin raw material; redeposited lignin; defoamers; surfactants; mixtures of organic insoluble salts; unsaponifiable organics; wood fibers; poorly soluble polymeric paper additives; waxes; stickies, optionally wherein the stickies are selected from the group consisting of sizing chemicals and adhesives; and microbiological deposits. 
     
     
         5 . The method of  claim 1 , wherein the liquid or slurry is a pulp slurry. 
     
     
         6 . A method for measuring the effectiveness of at least one inhibitor that decreases a rate of deposition of organic deposits in a papermaking process, the method comprising:
 providing a quartz crystal microbalance, the quartz crystal microbalance having a top side in contact with a liquid or slurry and a bottom side isolated from the liquid or slurry, the quartz crystal microbalance measuring a vibration frequency;   monitoring the rate of deposition of the organic deposits from the liquid or slurry by measuring the vibration frequency;   adding the at least one inhibitor that decreases the rate of deposition of the organic deposits to the liquid or slurry, wherein the adding is based upon the monitoring step; and   re-measuring the rate of deposition of the organic deposits from the liquid or slurry on to the quartz crystal microbalance by measuring the vibration frequency.   
     
     
         7 . The method of  claim 6  wherein the papermaking process occurs at location selected from the group consisting of: a pulp mill; a papermaking machine; a tissue making machine; a repulper; water loop; wet-end stock preparation; and deinking stages. 
     
     
         8 . A method for measuring the effectiveness of at least one inhibitor that decreases a rate of deposition of organic deposits in a papermaking process simulation, the method comprising:
 providing a quartz crystal microbalance, the quartz crystal microbalance having a top side in contact with a liquid or slurry and a bottom side isolated from the liquid or slurry, the quartz crystal microbalance measuring a vibration frequency; the liquid or slurry simulating that of a liquid or slurry found in a papermaking process;   monitoring the rate of deposition of the organic deposits from the liquid or slurry by measuring the vibration frequency;   adding the at least one inhibitor to the liquid or slurry, wherein the adding is based upon the monitoring; and   re-measuring the rate of deposition of the organic deposits from the liquid or slurry by measuring the vibration frequency.   
     
     
         9 . The method of  claim 4 , wherein the surfactants are silicon surfactants and optionally wherein the organic deposits are silicon surfactants and the papermaking process is a tissue repulping process. 
     
     
         10 . The method of  claim 1  wherein the top side of the quartz crystal microbalance is coated with at least one material selected from the group consisting of: polymeric films; monolayers; polylayers; surfactants; polyelectrolites; thiols; silica; aromatic sorbates; self-assembled monolayers; and molecular solids.