Cost Reduc­tion by Impro­ve­ments of Was­te Gas Treat­ment at a Sili­con Thin Film Solar Cell Mass Pro­duc­tion Line

Due to the pres­su­re for cost reduc­tion in a thin­film PV pro­duc­tion line an effort to redu­ce the run­ning cost of the was­te gas treat­ment sys­tems was started.

Impro­ved Was­te Gas treatment

As a pre­con­di­tion the DRE (Des­truc­tion Remo­val Effi­ciency) should not be redu­ced. Inten­ded impro­ve­ments for main­te­nan­ce and media con­sum­ptions were tes­ted on-site under pro­duc­tion con­di­tions over a 6‑month time frame.

Over­view of the thin­film PV pro­duc­tion line at Bao­ding Tianwei 
Point-of-use Abgasentsorgungskonzept Tianwei

The a‑Si/μc-Si CVD-pro­cess tools use lar­ge amounts of SiH4, H2, NF3 and TMB, PH3 as doping gases. The pro­cess gases are pyropho­ric, explo­si­ve or harm­ful to the envi­ron­ment. The­re­fo­re the pro­cess exhaust is trea­ted by com­bus­tion and wet scrub­bing point-of-use aba­te­ments in con­nec­tion with wet elec­tros­ta­tic dust collec­tors. Each day appro­xi­ma­tely 100 kg of SiO2 dust and 180 kg of HF are gene­ra­ted and retai­ned in the aba­te­ment sys­tems. The exhaust gases from the TCO tools con­tain DEZ, ZnO par­ti­cles and hydro­car­bons. Each TCO tool is con­nec­ted to a burn/wet was­te gas treat­ment sys­tem which oxi­di­zes com­bus­ti­ble com­pounds and retains particles.

Cost Reduc­tion Main­te­nan­ce: Main cau­ses and achie­ved improvements

Planmäßige Wartung Abgasentsorgung

KAI — Was­te gas treat­ment with GIANT/EDC

  • Par­ti­cle depo­sits in the reac­tor and con­nec­tion pipe to elec­tros­ta­tic dust collector 
    • Depo­sits in the reac­tor were much less than expec­ted → main­te­nan­ce inter­val extended
    • Added a self-clea­ning and main­te­nan­ce free pre-fil­ter to the con­nec­ting pipe → no more main­te­nan­ce of the con­nec­tion pipe required
  • Sedi­men­ta­tion of par­ti­cles in the cir­cuit tank → pre­ven­ted by increa­sed circulation/agitation of the washing fluid
  • Salt sca­ling tur­ned out the main cau­se of pro­blems → com­ple­tely eli­mi­na­ted by small chan­ges in the tank

 

ESCAPE — Main­te­nan­ce inter­vals befo­re begin­ning of tes­ting: same as for TCO tools

  • Obser­ved very small par­ti­cle depo­sits during maintenance
  • Mea­su­re: main­te­nan­ce inter­vals extended
  • Result: no nega­ti­ve impact on uptime

Uti­lity Savings at point-of-use was­te gas treatment

Was­te Gas Treat­ment Sys­tem GIANT

  • Opti­mi­za­tion of pH regi­me → redu­ced lye consumption
  • Pre­ven­tion of sedi­men­ta­tion and impro­ved fil­tra­tion of the scrub­bing liquid → higher con­cen­tra­tion of par­ti­cles in the liquid pos­si­ble, redu­ced water consumption

 

Was­te Gas Treat­ment Sys­tem ESCAPE

  • Redu­ced water con­sum­ption → no nega­ti­ve impact
Medienverbrauch für Abgasentsorgung

Con­clu­sion Cost Reductions

Based on sim­ple but con­se­quent impro­ve­ments the run­ning costs of the was­te gas treat­ment sys­tems can be redu­ced significant.

DAS Headquarter in Dresden

Your Con­tact for Was­te Gas Treat­ment in the Solar Industry:

Mr. Ray Morgan
Sr. Sales Manager