Tipton Gas Works 1954-1960
By David Humphries
The Works from the top of No. 4 Holder
Tipton Gas Works produced town gas. It was situated in Alexandra Road on part of the site now
occupied by the redundant gas from oil plant. The last coal gas plant was a Woodall Duckham
vertical retort plant opened in 1954 and closed in 1960. It replaced an earlier Glover West
vertical retort installation. The remains of this old works stood alongside the new for many
years.
Stock Piling
Coal in the form of washed singles and washed doubles was delivered into the stockyard by rail.
It was unloaded and stockpiled using a Jones KL44 mobile crane. It was essential not to pile it
excessively high because of the danger of spontaneous combustion within the heap. It was
therefore customary practice to sink steel tubes into the heap. Maximum/minimum
thermometers were kept permanently in these tubes to carefully monitor any temperature
changes.
The Production Process
Rotary Tipper
Coal was tipped from the railway waggon by a rotary tippler, passing into a receiving hopper
below and dropping into a crushing machine which reduced large pieces to a suitable size.
Production Process (continued)
A conveyor belt then transferred the coal to the
basement level of the retort house, discharging
it into one of two continuous bucket conveyors
which ran longitudinally around the building.
These conveyors carried the coal to the top of
the works where the coal storage bunkers were
situated. From here the coal passed at regular
intervals through a gas-tight valve into a much
smaller hopper below, which opened directly
into a retort.
The coal passed into the retort where it was
heated to a high temperature (up to 1300° C)
and the gas given off was taken off through pipes
for purification. As the coal passed down
through the retort at a controlled rate it lost all
of its volatile content until it became a residue of
hot coke. At the base of the retort this red hot
coke was quenched by a steam jet to cool it. This
had the added advantage of chemically
manufacturing water gas by reacting with the
coke - increasing the yield of the gas.
Producer landing and gas off-take necks to retorts odd side
Producer access covers can be seen in the floor. The chalk figures on the necks are
original damper opening details.
Production Process (continued)
At the bottom of the retort a helical screw cut
off the descending coke which collected below in
a gas-tight hopper which was discharged at
intervals. The discharged coke dropped into one
of the two longitudinal conveyors which could be
controlled to direct the coke into the screening
plant. Here it was graded into sizes and stored,
for sale, in large bunkers.
Coke Hoppers and Drive to No. 4 Even Side
The drive to the wheel controlling the helical screw
inside No. 4 retort shows that pair 3 and 4 are empty
for de-scaling. The inspection cover is lying on the steel
mesh floor. The pipe on the floor confirms an internal
flue leak is being welded. The rod running horizontally
controlled the rate of throughput. The “odd side” is
similar.
Purification
At Tipton there were eight purifiers, four
large units in one set, and four smaller units
installed as part of the Glover West
installation.
The impure coal gas was taken off the retort
through a cast-iron off-take pipe. To flush
out any solids which condensed there, tar
was sprayed into the pipe.
From the retort house the hot foul gas was
passed down through the primary
condenser where the bulk of the tar and
some of the ammonia were removed for
further processing. The partially clean gas
was then pumped through the remaining
stages of purification by one of a number of
steam driven exhausters (manufactured by
Bryan Donkin.)
Testing for tar in gas stream
Purification (continued
The gas then passed into a
large cast-iron ammonia
scrubber. Inside the scrubber
were layers of wooden grids
which were sprayed with
softened water creating a
large wet surface that readily
dissolved any remaining
ammonia in the gas. (The
water softener was a
Kennicot by John Thompson
of Wolverhampton.)
Ammonia Concentration Plant
From the scrubber the gas was passed down through secondary condensers to remove any
carried over ammonia. At this point the major remaining impurity was hydrogen sulphide – all
traces of which had to be removed by law. The gas was passed through layers of iron-oxide in
the form of a peat-like bog-ore contained on slatted wooden racks in large steel tanks supported
on a steel framework above ground (to facilitate emptying.) The chemical reaction between the
iron oxide and the hydrogen sulphide resulted in the deposition of sulphur. As this was an
exothermic reaction, the process had to be carefully monitored.
The gas was now sufficiently purified for use and after passing through the station meter, was
stored in one of Tipton’s four gasholders.
Waste Reduction
The by-products recovered at the Tipton works were all saleable.
Tar: was collected in a tar well where the ammonia which may still be present in it was
separated out. The tar was pumped into a storage tank to await collection by canal boat by
Midland Tar Distillers.
Ammonia: was pumped to the ammonia concentration plant. After processing it was stored to
await collection by rail by Brothertons.
Coke: a ready market was found for both domestic and industrial purposes. Part of the coke
output was kept in the retort house as fuel for the producer gas plant which made the gas for
heating the retorts. Some coke was also used for standby steam-raising on the works. Two
Lancashire boilers were installed for this purpose although under normal operating conditions
the waste-heat boiler was more than capable of meeting the demand for steam.
Sulphur: there were two customers for this – Albright and Wilson at Oldbury and I.C.I. at the
Willingsworth works. A greater yield of recoverable sulphur could be obtained if oxygen in the
form of air was introduced into the gas stream at the inlet to the purifiers. At Tipton a small
electrically powered blower was installed. When the iron oxide was saturated with sulphur in
the first purifier in the “stream” it could be rejuvenated by changing the sequence of the
purifiers. Eventually however the oxide would fail to react further and the affected purifier
would be taken out of stream, and opened. The spent-oxide was sampled and analysed to
determine its sulphur content. If the sulphur content was near 50% it was sold for the
manufacture of sulphuric acid. If the sulphur content was low then the oxide was mechanically
broken up and mixed with fresh bog-ore and used a second time.
Control
It was necessary to control the temperature in each of the “passes” (or flues) in
the retort on a daily basis. A low temperature gave a low gas yield of high
calorific value and a high proportion of impurities, whilst a high temperature
gave a high yield of gas at a lower calorific value with proportionally lower
impurity content. Sliding refractory brick dampers controlled:
• the volume of producer gas admitted
• the volume of hot primary air admitted
• the volume of secondary air admitted
• back pressure in the heating flues
By manipulating the damper openings it was relatively easy to control:
• the length of the heating flame
• the temperature
• the area within the flue where the temperature was highest
Bottom Passes (Even Side)
Temperatures are taken by flipping open viewing flaps in the small cast iron covers.
The covers rested in tapered guides to give a gastight seal. They were easily lifted off
to give access for removal of dust from the heating flues. The trolley arrangement
was used by the technician when taking the heating flue temperatures.
Control (continued)
The rate at which coal passed into the retorts
from the individual bunkers was monitored
from the outside by a simple indicator device
consisting of a chain passing over a pulley. On
the end in the bunker was a weight which
rested on top of the coal. On the outside was a
“D” shaped handle. The position of this handle
was marked at hourly intervals, with chalk, on
a cast-iron panel bolted to the outside of each
bunker. It is known that coal swells when
heated. For gas making it was necessary to use
a coal which caked well to make good coke but
with a minimum of swelling. Because of the
tendency to swell the charge passing down the
retort tended to “stick” and as a matter of
operating routine plugs were removed from
the top casting and long poker inserted to
assist the coal to travel smoothly. This was
known as “rodding”.
Len Mayo Rodding on Even Side c1958
The marker board and “D” ring for checking coal feed is seen on the right. The thin vertical pipe is the tar spray supply. The rodding holes are
sealed with cast iron plugs. The poker is some 12/14 feet long. The heavy timbers lying below the (always) open windows suggests Duckhams
are on site doing major re-lining. This was summer time work when gas demand was low.
Joe Atkins Cleaning the Producer Grate