A new onslaught of proposals to cripple the Federal Trade Commission, including one that would gut the agency's controversial Exxon case, are expected to be considered Tuesday by the Senate Commerce Committee.

With growing congressional support, as many as a dozen previously undisclosed amendments to the agency's funding bill will be the focus of next week's showdown, as industry lobbyists continue to press for a curtailment of the FTC's far reaching authority.

The new legislative activity comes on the heels of this week's House vote curbing the agency's authority to continue to press for funeral industry rules.

The House voted 223 to 147 to cripple the commission's ongoing funeral industry study, handing consumer and agency advocates a stunning defeat.

Now, the debate is heating up in the Senate. The most significant initiative there is an amendment by Sen. Howell Heflin (D-Ala.) that would bar the FTC from ordering divestiture "or other similar relief" in antitrust cases.

Enactment of such a proposal would end the five-year old Exxon case, in which eight major oil companies have been charged with anti-competitive practices in their refining operations. The FTC staff has proposed that the oil companies be forces to divest refineries and pipelines in the Exxon case.

In addition, the FTC's cereal industry case, which charges the nation's three leading cereal manufacturers with monopolistic practices, would also be halted.

As evidence of the cereal industry's clout, Heflin's staff has circulated a position paper outlining their case, which quotes consistently, and without attribution, from a 1974 motion filed by attorneys before the FTC for General Mills Inc. in an effort to kill the commission's complaint.

Besides the Heflin amendment, Sen. Howard Cannon (D-Nev.), the Commerce Committee's chairman, is expected to propose that the FTC be barred from investigating the insurance industry, in light of state regulation of insurance activites.

Sen. Wendell Ford (D-Ky.), chairman of the Senate Consumer subcommittee, last week proposed limiting amendments to the FTC authorization bill, causing the FTC and the Carter administration to respond with counterattacks.

All the time, key FTC officials viewed the Ford proposal as a "disaster," claiming that it would have effects far beyond those realized by Ford.

But now, faced with this new series of even tougher proposals, top commission officials are beginning to bank on Ford to stem the tide.

"I think Ford is trying to walk what he sees as the middle line," said a top FTC official. "In large part, we are now in his hands."

"Every lobby wants its piece of the action," said one FTC source.

Some of the new proposals would:

Prevent the agency from regulating professionals, such as doctors and lawyers. The FTC has actively fought the powers of the trade associations in the professions, seeking to reduce their powers by ending such things as bars against advertising.

Limit the subpoena power of the FTC in all of its investigations and allow earlier and more court challenges to subpoenas that are issued.

Eliminate all, or some, of the funding earmarked for public participation. This would end the practice of subsiding the appearance of consumer organizations in FTC proceedings.

In an interview, subcommittee chairman Ford said his staff "is making some changes," and acknowledged that he has come under "some heat" from colleagues in the Senate to take a tougher line against the commission.