Updated: July 2002

1. Purpose

CT-242 (Chiyoda Thoroughbred 242) contributes to keep the water environment clean by removing oil, soluble organic compounds, hazardous substances, color matters, malodor substances, and so on, in wastewater discharged from petroleum refinery, petrochemical plant, chemical plant, steelworks, paper-pulp plant, and others.

2. Performance

Typical examples of the substances to be treated and their economically applied ranges are listed below.
Figures show concentration in mg/l.

Substances to          Available         After Treatment
be Treated              Range
Oil                      <10                   <1
COD                    100-200                 <15
BOD                    100-200                 <15
Sulfides                 <3                    <1
Phenol                   <25                   <0.5
ABS                      <1                    <0.1

3. Process Configuration

This is a continuous wastewater treatment process using granular activated carbon as an adsorbent, which is composed of Adsorption Section, Regeneration Section and Off-gas Treatment Section. Activated carbon is recirculated between the Adsorption Section and the Regeneration Section. The adsorber has several trays for multi-stage fluidization, and the activated carbon moves through the trays by pulse-transporting method. Wastewater is introduced from the bottom of the adsorber to contact countercurrently with activated carbon. The Regeneration Section is composed of regenerator, combustor, and others. The regenerator has two fluidizing beds, a drying/desorbing bed at 300 to 400ºC, and an activating bed at 700 to 800ºC. There are two types of regenerators, internal heating and external heating. Off-gas emitted from the regenerator, which contains various kinds of organics and other substances removed from the wastewater, is treated in the Off-gas Treatment Section.

4. Characteristics

1) Total inventory of charged activated carbon is minimal, because the continuous and countercurrent contact is applied in the adsorber.
2) Due to the pulse-transporting method for activated carbon in the adsorber, a back mixing does not occur and the efficiency of activated carbon usage per 1 cycle is very high.
3) Operating cost with the regeneration section is lower, compared with contacted regeneration by outside factories.
The merit becomes larger, as the capacity increases.
4) Operation of the regenerator with the fluidizing method is easy.
5) Loss of activated carbon through regeneration can be minimized by optimizing operation temperature and residence time in the regenerator, depending on the properties of the adsorbed substances.

5. Process Flow

Process Flow Sheet of CHIYODA THOROUGHBRED-242 (CT-242) for Water Treatment (with Internal-Heating Regenerating System)

6. Application

Petroleum refinery
Chemical and petrochemical plant
Iron and steel manufacturing plant
Paper pulp plant
Municipal water treatment and Sewage treatment plant
Others

7. Experience

Petroleum refining wastewater treatment at domestic petroleum refineries
Plant wastewater treatment at domestic chemical plants
Plant wastewater treatment at domestic research institutes
Plant wastewater treatment at domestic steelworks
Plant wastewater treatment at domestic food plants
Oily wastewater treatment at overseas petroleum refineries
(The process is licensed to SHINKO PANTEC.)