224:
122:
25:
238:
Almost all fluids can undergo supercritical drying as a physical chemistry process, but the harsh conditions involved will often make it impractical as part of an industrial process. Fluids which do see industrial application of supercritical drying include
295:
is unavailable. The liquid carbon dioxide is then heated until its temperature goes beyond the critical point, at which time the pressure can be gradually released, allowing the gas to escape and leaving a dried product.
279:
is inconvenient due to possible heat damage to a sample at its critical point temperature (647 K, 374 °C) and corrosiveness of water at such high temperatures and pressures (22.064 MPa, 3,212 psi).
207:. Supercritical drying, on the other hand, goes around the line to the right, on the high-temperature, high-pressure side (red arrow). This route from liquid to gas does not cross any
199:
To avoid this, the sample can be brought via two possible alternate paths from the liquid phase to the gas phase without crossing the liquid–gas boundary on the phase diagram. In
215:
region, where the distinction between gas and liquid ceases to apply. Densities of the liquid phase and vapor phase become equal at critical point of drying.
196:, and the tiny machinery of microelectromechanical devices, tend to be broken apart by this surface tension as the liquid–gas–solid junction moves by.
361:
336:
42:
129:
of the working fluid in order to avoid the direct liquid–gas transition seen in ordinary drying (green arrow) or the two phase changes in
203:, this means going around to the left (low temperature, low pressure; blue arrow). However, some structures are disrupted even by the
108:
89:
61:
244:
126:
291:
of these two fluids. The acetone is then washed away with high pressure liquid carbon dioxide, the industry standard now that
204:
149:
46:
68:
223:
388:
173:
188:
in the liquid body pulls against any solid structures the liquid might be in contact with. Delicate structures such as
260:
75:
383:
57:
393:
184:
at a finite rate, while the amount of liquid decreases. When this happens within a heterogeneous environment,
35:
276:
212:
82:
357:
332:
326:
208:
185:
240:
231:
161:
377:
305:
268:
252:
227:
200:
177:
130:
288:
24:
193:
189:
272:
284:
256:
157:
267:(≈300 K at 3.5–4 MPa or 25–0 °C at 500–600 psi).
248:
145:
148:
in a precise and controlled way. It is useful in the production of
328:
Modern Drying
Technology, Volume 3: Product Quality and Formulation
271:
has similar physical behavior to carbon dioxide, but is a powerful
292:
264:
153:
121:
120:
287:
is first used to wash away all water, exploiting the complete
181:
18:
164:
of coffee and in the preparation of biological specimens.
325:
Evangelos
Tsotsas; Arun S. Mujumdar (29 August 2011).
354:
Scanning electron microscopy and X-ray microanalysis
49:. Unsourced material may be challenged and removed.
230:showing the supercritical region (light blue) of
125:Supercritical drying (red arrow) goes beyond the
8:
275:in its supercritical state. Supercritical
172:As the substance in a liquid body crosses
109:Learn how and when to remove this message
331:. John Wiley & Sons. pp. 185–.
222:
317:
7:
47:adding citations to reliable sources
14:
23:
174:the boundary from liquid to gas
34:needs additional citations for
211:, instead passing through the
150:microelectromechanical systems
1:
180:), the liquid changes into
410:
356:. John Wiley & Sons.
144:, is a process to remove
283:In most such processes,
16:Process to remove liquid
352:Grahame Lawes (1987).
235:
152:(MEMS), the drying of
134:
58:"Supercritical drying"
226:
142:critical point drying
124:
389:Industrial processes
176:(see green arrow in
156:, the production of
138:Supercritical drying
43:improve this article
192:, the dendrites in
236:
205:solid–gas boundary
135:
363:978-8-126-5-17305
338:978-3-527-31558-1
119:
118:
111:
93:
401:
384:Drying processes
368:
367:
349:
343:
342:
322:
140:, also known as
114:
107:
103:
100:
94:
92:
51:
27:
19:
409:
408:
404:
403:
402:
400:
399:
398:
394:Microtechnology
374:
373:
372:
371:
364:
351:
350:
346:
339:
324:
323:
319:
314:
302:
221:
186:surface tension
170:
115:
104:
98:
95:
52:
50:
40:
28:
17:
12:
11:
5:
407:
405:
397:
396:
391:
386:
376:
375:
370:
369:
362:
344:
337:
316:
315:
313:
310:
309:
308:
301:
298:
245:critical point
241:carbon dioxide
232:carbon dioxide
220:
217:
209:phase boundary
169:
166:
162:decaffeination
127:critical point
117:
116:
31:
29:
22:
15:
13:
10:
9:
6:
4:
3:
2:
406:
395:
392:
390:
387:
385:
382:
381:
379:
365:
359:
355:
348:
345:
340:
334:
330:
329:
321:
318:
311:
307:
306:Freeze-drying
304:
303:
299:
297:
294:
290:
286:
281:
278:
274:
270:
269:Nitrous oxide
266:
262:
259:at 1072
258:
255:or 31.1
254:
251:at 7.39
250:
246:
242:
233:
229:
228:Phase diagram
225:
218:
216:
214:
213:supercritical
210:
206:
202:
201:freeze-drying
197:
195:
191:
187:
183:
179:
178:phase diagram
175:
168:Phase diagram
167:
165:
163:
159:
155:
151:
147:
143:
139:
133:(blue arrow).
132:
131:freeze-drying
128:
123:
113:
110:
102:
91:
88:
84:
81:
77:
74:
70:
67:
63:
60: –
59:
55:
54:Find sources:
48:
44:
38:
37:
32:This article
30:
26:
21:
20:
353:
347:
327:
320:
282:
247:304.25
237:
198:
171:
141:
137:
136:
105:
96:
86:
79:
72:
65:
53:
41:Please help
36:verification
33:
289:miscibility
378:Categories
312:References
194:silica gel
190:cell walls
99:April 2017
69:newspapers
300:See also
273:oxidizer
285:acetone
158:aerogel
83:scholar
360:
335:
263:) and
219:Fluids
160:, the
154:spices
146:liquid
85:
78:
71:
64:
56:
293:freon
277:water
265:freon
90:JSTOR
76:books
358:ISBN
333:ISBN
62:news
261:psi
253:MPa
182:gas
45:by
380::
257:°C
366:.
341:.
249:K
243:(
234:.
112:)
106:(
101:)
97:(
87:·
80:·
73:·
66:·
39:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.