Quenched Granular Absorbent and System and Method for Making Quenched Granular Absorbent

Patent metadata

Field	Value
Publication number	US-2016346981-A1
Application number	US-201515114069-A
Country	US
Kind code	A1
Filing date	Jan 26, 2015
Priority date	Jan 25, 2014
Publication date	Dec 1, 2016
Grant date	—

Abstract

A system and method of extruding self-clumping granular absorbent having cold water soluble amylopectin starch binder formed from starch-containing admixture sufficient for extruded sorbent pellets to produce flowable binder flowing between pellets clumping them together producing clumps of pellets that become hard when substantially dry that have a crush strength of at least 25 PSI and clump retention of at least 80% and preferably at least 90%. As a result, dried pellet clumps are easy to pick up leaving behind unspent pellets for continued sorbent use. A pellet quenching apparatus and method rapidly cools and dries pellets before leaving the extruder preventing loss of cold water soluble starch and binder, preventing pellet shrinkage, and preventing pellet densification. An air conveyor transporting quenched pellets removed from the extruder further cools and dries the pellets producing pellets ready for sorbent use.

First claim

What is claimed is:

1 . A method of making granular sorbent comprising:
(a) providing an extruder and a starch-containing admixture; and (b) extruding the starch-containing admixture at or above (i) an extruder temperature, and (ii) extruder pressure forming sorbent pellets extruded from the extruder each having at least 15% cold water soluble starches by pellet weight including cold water soluble starch binder sufficient to produce clumps each comprised of a plurality of pairs of the adjacent sorbent pellets when the sorbent pellets forming the clump are wetted with water.

2 . The granular sorbent method of claim 1 wherein each clump has a clump crush strength of at least 25 pounds per square inch when the clump is substantially dry.

3 . The granular sorbent method of claim 2 wherein each clump has a clump crush strength of at least 25 pounds per square inch when the clump has a moisture content no greater than 15% by clump weight.

4 . The granular sorbent method of claim 3 wherein each clump has a clump crush strength of at least 25 pounds per square inch when the clump has a moisture content of between 6% and 12% by clump weight.

5 . The granular sorbent method of claim 1 wherein each clump has a clump crush strength of at least 25 pounds per square inch and a clump retention rate of at least 95% when the clump is substantially dry.

6 . The granular sorbent method of claim 1 wherein each sorbent pellet has at least 10% cold water soluble starch binder by uncoated pellet weight producing clumps each formed of a plurality of pairs of wetted pellets having a clump crush strength of at least 25 pounds per square inch and a clump retention rate of at least 80% when the clump is substantially dry.

7 . The granular sorbent method of claim 1 wherein each sorbent pellet has at least 15% cold water soluble starch binder by uncoated pellet weight producing clumps each formed of a plurality of pairs of wetted pellets having a clump crush strength of at least 30 pounds per square inch and a clump retention rate of at least 90% when the clump is substantially dry.

8 . The granular sorbent method of claim 1 wherein each sorbent pellet has at least 15% cold water soluble starch binder by uncoated pellet weight producing clumps each formed of a plurality of pairs of wetted pellets having a clump crush strength of at least 40 pounds per square inch and a clump retention rate of at least 95% when the clump is substantially dry.

9 . The granular sorbent method of claim 1 wherein the sorbent pellets are extruded from the extruder at a pellet extrusion temperature and comprising the further step of quenching each pellet by reducing pellet temperature to a temperature that is at least 15 degrees Celsius less than the pellet extrusion temperature by the time the sorbent pellet is removed from the extruder.

10 . The granular sorbent method of claim 9 wherein each pellet removed from the extruder after quenching is completed has a temperature no higher than 83 degrees Celsius.

11 . The granular sorbent method of claim 10 further comprising a quenching chamber disposed at a discharge end of the extruder in which the sorbent pellets extruded from the extruder are received, the quenching chamber in fluid flow communication with a pellet discharge that removes each pellet from the extruder when pellet quenching is completed.

12 . The granular sorbent method of claim 11 wherein the extruder comprises: (a) a rotary cutter that cuts sorbent pellets discharged from an extruder die in extruding the sorbent pellets, (b) a knife cage enclosing the rotary cutter and extruder die, the knife cage forming at least part of the quenching chamber, and (c) a quenching air mover that delivers quenching air into the knife cage at a sufficient volumetric flow rate, low enough temperature and low enough humidity to cool each sorbent pellet during quenching by at least 15 degrees Celsius from the pellet extrusion temperature to a temperature no greater than 83 degrees Celsius when quenching is completed.

13 . The granular sorbent method of claim 12 wherein the knife cage is substantially gas-tight and wherein the quenching air received in the knife cage pressurizes at least the knife cage above ambient pressure.

14 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber retrogrades amylose starch in each pellet.

15 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber retrogrades amylose starch in each pellet hardening each pellet.

16 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber prevents moisture vaporizing in each pellet from solubilizing or dissolving water soluble starches in each pellet.

17 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber prevents moisture vaporizing in each pellet from solubilizing or dissolving cold water soluble starches in each pellet.

18 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber prevents moisture vaporizing in each pellet from solubilizing or dissolving cold water soluble starch binder in each pellet.

19 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber prevents moisture vaporizing in each pellet from solubilizing or dissolving cold water soluble amylopectin starch binder in each pellet.

20 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber prevents moisture vaporizing in each pellet from changing the state of amorphous water soluble starches in each pellet.

22 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber prevents moisture vaporizing in each pellet from changing the state of amorphous water soluble amylopectin starch binder in each pellet.

23 . The granular sorbent method of claim 11 wherein quenching of each sorbent pellet in the quenching chamber prevents moisture vaporizing in each pellet from changing the state of amorphous cold water soluble amylopectin starch binder in each pellet.

24 . A granular absorbent extrusion system for producing extruded granular sorbent comprising an extruder having a perforate extruder die disposed at a discharge end of the extruder from which sorbent pellets are extruded from a starch-containing admixture during extruder operation.

25 . The extrusion system of claim 24 wherein the sorbent pellets are extruded by the extruder having sufficient water soluble binder in each sorbent pellet formed from starch in the starch-containing admixture during extrusion for a plurality of pellets wetted with water to form a clump containing at least a plurality of pairs of the pellets having a clump crush strength of at least 25 pounds per square inch and a clump retention rate of at least 80% when the clump is substantially dry.

26 . The extrusion system of claim 25 wherein each sorbent pellet extruded from the starch-containing admixture contains at least 10% water soluble starch in each sorbent pellet.

27 . The extrusion system of claim 26 wherein each sorbent pellet extruded from the starch-containing admixture contains at least 10% cold water soluble starch binder in each so

Assignees

• Pioneer Pet Products Llc

Inventors

• Lipscomb John M

Classifications

• B01J20/3042

  Use of binding agents; addition of materials ameliorating the mechanical properties of the produced sorbent · CPC title

• B01J20/3028

  Granulating, agglomerating or aggregating · CPC title

• B01J20/3007 Primary

  Moulding, shaping or extruding · CPC title

• A01K1/0154

  comprising inorganic material · CPC title

• B29B9/16 Primary

  Auxiliary treatment of granules · CPC title